Band 9, Heft 1

The locally-exact homogenization theory is further extended to investigate the homogenized and localized electric behavior of unidirectional composite and porous materials. Distinct from the classical and numerical micromechanics models, the present technique is advantageous by developing exact analytical solutions of repeating unit cells (RUC) with hexagonal and rhomboid geometries that satisfy the internal governing equations and fiber/matrix interfacial continuities in a point-wise manner. A balanced variational principle is proposed to impose the periodic boundary conditions on mirror faces of an RUC, ensuring rapid convergence of homogenized and localized responses. The present simulations are validated against the generalized Eshelby solution with electric capability and the finite-volume direct averaging micromechanics, where excellent agreements are obtained. Several micromechanical parameters are then tested of their effects on the responses of composites, such as the fiber/matrix ratio and RUC geometry. The efficiency of the theory is also proved and only a few seconds are required to generate a full set of properties and concomitant local electric fields in an uncompiled MATLAB environment. Finally, the related programs may be encapsulated with an input/output (I/O) interface such that even non-professionals can execute the programs without learning the mathematical details.

In order to meet the increasing engineering requirements, the ultra-early strength of sulphoaluminate cement (SAC)-based materials need to be improved to achieve road repair, engineering rescue and other objectives. Graphene oxide (GO) of 0.04 wt% was incorporated into SAC mortar to prepare GO enhanced SAC mortar (GO-SAC). It was found that the compressive strength of GO-SAC was increased by 46.9% at the age of 6 hours, and the flexural strength of GO-SAC was increased by 121.4% at the age of 100 minutes, compared with the control SAC mortar. The mechanism analysis based on the characterization results derived from XRD, BET, in situ ATR-FTIR, hydration heat measurement, TG–DSC and SEM showed that, the addition of minute quantities of GO led to the formation and growth of ribbon-like AFt,which further resulted in the improvement of the ultra-early strength of GO-SAC. This work indicates that GO has great potential for practical application in the preparation of high-performance SAC-based materials with ultra-early strength.

The carbon nanofibers and molybdenum disulfide (CNF-MoS 2 ) nanohybrid material was fabricated and incorporated into epoxy resin to form the nanocomposite coating. Firstly, microstructure observation shows that each CNF was uniformly wrapped up with MoS 2 nanosheets, and the nanohybrids were well dispersed in the coating. Then, nanoindentation experiments were carried out to explore the effect of the CNF-MoS 2 nanohybrids on the mechanical properties of the epoxy resin coating. The results demonstrate that elastic modulus, hardness and creep deformation resistance of the CNF-MoS 2 epoxy resin coating are greatly increased in comparison with both pure epoxy resin and MoS 2 epoxy resin coatings. Finally, the underlying mechanism of high-performance tribological behavior of the nanocomposites is analyzed accordingly. It can be concluded that the wrapped structure with MoS 2 sheets growing on the surface of CNF increases the contact area and reduces the friction coefficient of the composite coating, while the wear resistance of the nanocomposite coating is also greatly improved due to the superior high hardness of CNF.

Reinforcing polymers with nanofillers is an advanced approach to improve and manage the thermal behaviors of polymeric nanocomposite materials. Among the proposed nanofillers, graphene and carbon nanotube (CNT) with superior thermal conductivity are two advanced nanofillers, which have extensively been utilized to enhance the heat transfer responses of host polymeric materials. In this work, the impacts of randomly oriented graphene and CNT to steady state and transient heat transfer behaviors of functionally graded (FG) nanocomposite cylinders have been investigated using an axisymmetric model. Nanocomposite cylinders have been assumed to be under heat fluxes, heat convections or temperatures as different types of thermal boundary conditions. The thermal properties of the resulted nanocomposite materials are estimated by micromechanical model. Moreover, the governing thermal equations of axisymmetric cylinders have been analyzed using a highly consistent and reliable developed mesh-free method. This numerical method predicts temperature fields via MLS shape functions and imposes essential boundary conditions with transformation approach. The effects of nanofiller content and distribution as well as thermal boundary conditions on the heat transfer responses of nanocomposite cylinders are studied. The results indicated that the use of nanofiller resulted in shorter stationary times and higher temperature gradients in FG nanocomposite cylinders. Moreover, the use of graphene in nanocomposites had stronger impact on thermal response than CNT. Graphical abstract

A novel, scalable methacrylated graphene oxide (MeGO) nanostructured polyaniline (PANI) nanocomposite was synthesized and electrodeposited on the surface of fluorine-doped tin oxide electrode (FTOE). The two-dimensional support maintained a suitable substrate and arrayed in a conductive polymer matrix, creating an ultra-superconductive platform with extraordinary characteristics. The versatility of the nanocomposite performance was corroborated by altering the amount of MeGO coated on FTOE and changing the charge density of electro-polymerized PANI on the substrate. This exceptional nanostructure material enabled a robust platform design that demonstrated the extraordinary performance with enhanced conductivity and stability. Charge transfer resistance ( R ct ) was dramatically decreased from 11,000 (for bare FTOE) to 65 (for MeGO/PANI).

The ultrasmall nanoparticles easily lead to a more seriously response than larger nanoparticles because of their physicochemical features. It is essential to understand their cytotoxicity effects for their further application. Here, we used ultrasmall 9 nm Fe 3 O 4 NPs to explore its cytotoxicity mechanism on breast cancer cells. We demonstrated 9 nm Fe 3 O 4 NPswas effectively internalized into cells and located in nucleus, subsequently, it inhibited DNA synthesis through inducing S-phase arrest.Moreover, 9 nm Fe 3 O 4 NPs induced ROS production and oxidative damage by disturbing the expression of antioxidant-related genes (HMOX-1, GCLC and GCLM), which resulted in the enhancement of cells apoptosis and inhibition of cell proliferation, suggesting its potential to be used as therapeutic drug.

In this paper, the Cu-0.52Ag-0.22Cr alloy was prepared by hot horizontal continuous casting. The effects of aging process on micro-hardness, electrical conductivity, and nanoscale precipitates of Cu-0.52Ag-0.22Cr alloy were studied. The electrical conductivity and micro-hardness increase significantly in the early aging time. With the extension of aging time, the electrical conductivity is basically unchanged and remains at a high level. While, the micro-hardness increases slowly, the change trend is different at 623 K, 723 K, and 773 K. The optimisation of process parameters occurs in 723 K for 2 h. At this time, the electric conductivity is 95.8% IACS and the hardness is 104.1 HV0.1. The XRD result shows that the Ag and Cr are precipitated in elemental form copper matrix. Further TEM shows that, Cr exists at the sub-boundary in the form of larger nanoscale precipitates (100-200 nm). While a large number of Ag nanoscale precipitates (8-10 nm) is dispersed on the copper matrix. The synergistic effect of Ag and Cr nanoscale precipitates significantly improved the properties of the alloy.

Influence of nano-strengthening immersion on the properties of recycled aggregate (RA) and recycled aggregate concrete (RAC) and the microstructure of interfacial transition zones (ITZs) between mortar and aggregate were studied in this paper. Results showed that nano-strengthening immersion was helpful to reduce the crushing value and total pore area of RA, to significantly improve the mechanical strength of RAC, and to modify the bond strength between RAC and steel rebar and the structural properties of RAC beams. Mercury intrusion porosimetry (MIP), micro-hardness (MH) and scanning electron microscope (SEM) observation were conducted in order to reveal the enhancement mechanism of nano-strengthening immersion. Results showed that the density and mechanical properties in ITZs were obviously improved by nano-strengthening because the coating and penetration of nano-materials was helpful to block the pores and cracks in ITZs, to avoid the directed gathering of CH crystal, and to accelerate the hydration of cement and mineral additions.

Multi-walled carbon nanotubes (MWCNTs) have been added in the plain cementitious materials to manufacture composites with the higher mechanical properties and smart behavior. The uniform distributions of MWCNTs is critical to obtain the desired enhancing effect, which, however, is challenged by the high ionic strength of the cement pore solution. Here, the effects of methylcellulose (MC) on stabilizing the dispersion of MWCNTs in the simulated cement pore solution and the viscosity of MWCNT suspensions werestudied. Further observations on the distributions of MWCNTs in the ternary cementitious composites were conducted. The results showed that MC forms a membranous envelope surrounding MWCNTs, which inhibits the adsorption of cations and maintains the steric repulsion between MWCNTs; thus, the stability of MWCNT dispersion in cement-based composites is improved. MC can also work as a viscosity adjuster that retards the Brownian mobility of MWCNTs, reducing their re-agglomerate within a period. MC with an addition ratio of 0.018 wt.% is suggested to achieve the optimum dispersion stabilizing effect. The findings here provide a way for stabilizing the other dispersed nano-additives in the cementitious composites.

With the rapid development of electronics and information technology, electronics and electrical equipment have been widely used in our daily lives. The living environment is full of electromagnetic waves of various frequencies and energy. Electromagnetic wave radiation has evolved into a new type of environmental pollution that has been listed by the WHO (World Health Organization) as the fourth largest source of environmental pollution after water, atmosphere, and noise. Studies have shown that when electromagnetic wave radiation is too much, it can cause neurological disorders. And electromagnetic interference will cause the abnormal operation of medical equipment, precision instruments and other equipment, and therefore cause incalculable consequences. Therefore, electromagnetic protection has become a hot issue of concern to the social and scientific circles.

With molecular dynamics simulations, nanocomposites were characterized that are comprised of a polyimide (PI) polymer and carbon nanotubes (CNTs) with the same outer diameter but with one, two, or three walls. The simulations indicate that the PI/CNT interaction is strong, regardless of the number of CNT walls, and that there is some degree of alignment of the PI chains near the CNT interface. As the number of CNT walls increased, the density of PI chains near the CNT interface also increased and the average radius of gyration of the PI chains decreased, and these observations were attributed to changes due to the intertube van der Waals interactions. From simulations of the constant force pullout process of the CNT from the PI matrix, the limiting pullout force was calculated to be higher for the triple-walled CNT than for the single-walled one. The interfacial shear strength of the nanocomposites was also calculated from the pullout energy, and the results indicate that increasing the number of walls is a critical factor for enhancing the interfacial stress transfer during tension.

In this paper, the 3D pore structure of CuCr powders were obtained by pre-press shaping process, and finally the 3D interconnected carbon nanotubes/copper (CNTs/Cu) composites with excellent properties were insitu synthesized by chemical vapor deposition (CVD) and spark plasma sintering (SPS) technique. The morphology and structure of CNTs/ Cu composites are characterized by scanning electron microscopy (SEM), Raman spectra, transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), and the results showed that the quality of CNTs and the interfacial bonding strength of CNTs/ Cu composites can be improved owing to the 3D pore structure. Meanwhile, the 3D pore structure was favorable to avoid pollution of CNTs during the synthesis process. The tensile strength of CNTs/ Cu composites increased to 421.2 MPa, with 47.6% enhancements compared to CuCr. Furthermore, the coefficient of friction (COF) reduced to 0.22 and the corrosion resistance were increased by 51.86% compared to CuCr. Consequently, our research provides a novel and an effective method for the synthesis of high quality CNTs/ Cu composites.

The surface activity of carbon black (CB) is an important factor affecting the reinforcement of rubber. The quantitative determination of the surface activity (surface free energy) of CB is of great significance. A simplified formula is obtained to determine the free energy of CB surface through theoretical analysis and mathematical derivation. The surface free energy for four kinds of industrial CBs were measured by inverse gas chromatography, and the influential factors were studied. The results showed that the aging time of the chromatographic column plays an important role in accurate measurement of the surface free energy of CB, in comparison with the influences from the inlet pressure and carrier gas flow rate of the chromatographic column filled with CB. Several kinds of industrial CB were treated at high temperature, and the surface free energy of CB had a significant increase. With the increase of surface free energy, the maximum torque was decreased significantly, the elongation at break tended to increase, the heat generation of vulcanizates was increased, and the wear resistance was decreased.

Nano-silica modified phenolic resin film is prepared using different mass fractions of nano-silica by liquid composites molding (LCM). The effects of nano-silica on the rheology and curing of phenolic resin are studied by rheometer and differential scanning calorimeter (DSC). The results show that the viscosity of nano-silica modified phenolic resin decreases with the increase of temperature, and the viscosity is lowest between 70°C and 90°C. The appropriate resin film infusion (RFI) process is investigated, and the stepped curing process system is established. In addition, the microstructures of modified phenolic film and composites are tested by scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). Nano-silica can be uniformly dispersed in phenolic resin when the amount of nano-silica added is ≤ 4%. And the mechanical properties of nano-silica modified phenolic composites are tested by universal material testing machine. The optimum nano-silica mass loading for the improvement of mechanical properties is found. This work provides an effective way to prepare the modified phenolic resin film suitable for resin film infusion (RFI) processes, and it maybe become a backbone of thermal protection material in aerospace.

The photocatalytic mixed crystal nano-TiO 2 particles were incorporated with concrete by means of the internal doping method (IDM) and spraying method (SPM) in this paper. To evaluate the photocatalytic degradation efficiency of mixed crystal nano-TiO 2 concrete, the methyl orange (MO) was chosen to simulate pollutants. The physicochemical characteristics and photocatalytic performance of mixed crystal nano-TiO 2 concrete prepared by above two different methods were experimentally investigated under UV irradiation and solar irradiation. Furthermore, the effects of two key influential factors including pollutant concentration and irradiation condition were also analyzed and discussed. Experimental results indicate that the nano-TiO 2 concrete prepared by the spraying method (SPM) exhibits maximum photocatalytic degradation efficiency of 73.82% when the sprayed nano-TiO 2 slurry concentration is 10mg/L. The photocatalytic degradation efficiency of unpolished nano-TiO 2 concrete is much higher than that of polished nano-TiO 2 concrete under the same exposure time of UV irradiation. Moreover, the photocatalytic degradation efficiency of nano-TiO 2 concrete decreases with the increase of pollutant concentration. The irradiation condition has an obvious influence on the photocatalytic degradation efficiency of nano-TiO 2 concrete. In the aspect of applications, the practical recommendations for the nano-TiO 2 concrete with self-cleaning capacity were presented according to the experimental results.

Halloysite nanotubes (HNTs) are natural tubular materials, which show a number of attractive advantages such as the unique micro-spatial structure, large length-diameter ratio, high lumen volume, nontoxicity and widespread. The development of HNTs-based polymer composites expanded their applications in the fields of energy, catalysis, biomedicine, environmental protection and many others. This review will briefly summarize the purification, characterization and modification methods upon HNTs, in which the preparation and application of the HNTs-based polymer composites are emphasized. This paper may be beneficial for the development of novel strategies for the preparation of new libraries of HNTs-based polymer composites and the exploration of their applications.

Cellulose is the most abundant natural polymer on earth, which has obtained increasing interest in the field of functional materials development for its renewable, high mechanical performance and environmental benign. In this study, the traditional processing method (wet spinning and film production) of cellulose-based materials was applied by using cellulose solution for 3D printing, which can directly build complex 3D patterns. Herein, a natural cellulose is dissolved in an effective mixed aqueous solution of dimethyl sulfoxide (DMSO) and tetrabutylammonium hydroxide (TBAH). The cellulose solution extrusion was controlled by a modified fused deposition modeling (FDM) 3D printer. During the controlled extrusion 3D printing process, the viscous cellulose solution will gelifies and further solidifies into a predetermined 3D pattern at room temperature in air. Subsequently, a cellulose hydrogel skeleton was obtained, when the 3D pattern was solvent-exchanged with deionized water. Finally, the mechanical and swelling performance of the cellulose hydrogel scaffold was improved by a cross-linking agent treatment method. With treatment of the 3D printed scaffolds in 0.8 wt% cross-linking agent solution, the obtained cellulose hydrogel could absorb 28 g/g water, and the compression strength was 96 kPa. This work provided an efficient way to prepare natural cellulose hydrogel by 3D printing under room temperature.

In this study, an experimental investigation was conducted to assess the flexural tensile strength and crack-closing performance of mortar beams containing short shape memory alloy (SMA) fibers, randomly distributed only on the tensile side. The SMA fibers were mainly composed of titanium (Ti), nickel (Ni), and niobium (Nb). In addition, the effect of tensile steel wires on the flexural strength and crack-closing performance was evaluated. A four-point bending test was performed to evaluate the post-cracking tensile strength. This study also suggested a proper model to calculate the ultimate flexural moment of the SMA fiber–embedded beams. Subsequently, a heating plate that could be installed at the bottom of the beam was used to induce the shape memory effect and measure the closed crack width. This study assessed the crack-closing performance induced by the SMA fibers at the bottom side of the beams and the resistance of the tensile wires in the beams.

The curing and cellular structure of natural rubber (NR)/silica composite foams were investigated. The presence of an activator in the rubber formulation significantly lowered the decomposition temperature of the azodicarbonamide foaming agent, which allowed foaming before NR curing. Therefore, two foam methods were designed: foaming initially at 90°C and then curing at 140°C, and foaming and curing simultaneously at 140°C. Two-step foaming generated a lower cell density and higher cell size. Incorporation of nano silica into NR increased the foam density, but decreased the cell size. The higher foaming temperature restricted the bubble growth because of a higher curing rate and inhibited cell coalescence.

Recycling of red mud (RM) has attracted more attention in recent years due to severe environmental problems caused by landfilling. The effect of composition optimization and Nano-strengthening on the properties of a binder based on RM was studied in this paper. Results showed that modifying ratios of main oxides and adding Nano-SiO 2 could obviously affect the mechanical properties and microstructure of the binder. Specimens with high SiO 2 /Al 2 O 3 molar ratio (S/A) displayed considerable increase in compressive strength, while decreasing Na 2 O/Al 2 O 3 molar ratio (N/A) improved the workability of the fresh mix. The compressive strength was developed significantly to be 45 MPa at 28 days by adding Nano-SiO 2 with 0.4 wt.% of RM. Phase transformation and microstructure change at different stages of RM decomposition and binder geopolyerization were investigated by X-ray diffraction (XRD), Fourier transformation infrared (FTIR) and Scanning electron microscopy (SEM). The results of this study may provide a prospective method to use RM more widely in construction applications. Graphical abstract

Supercritical hydrothermal synthesis of nanosized metal oxides is of great interest for scholars due to its one-pot and readily realizing commercial production process. Hydrothermal synthesis of nanosized TiO 2 in subcritical and supercritical water was investigated with different reaction temperatures (250–450°C), time (3–10 min), precursor species (Ti(SO 4 ) 2 , TiCl 4 ), and the addition of a surfactant (CH 3 (CH 2 ) 5 NH 2 ). TiO 2 synthesized under supercritical state has a higher degree of crystallinity when compared with TiO 2 obtained from subcritical state, which is attributed to a higher reaction rate. Extending reaction time from 3 to 10 min leads to the growth of crystal and broader size distribution (36.66 ± 8.5 nm). More uniform products can be obtained when Ti(SO 4 ) 2 acting as the precursor compared with TiCl 4 being the precursor. The application of surfactant CH 3 (CH 2 ) 5 NH 2 in the synthesis makes chemical bonding between the particle surface and organic ligand. It affects the growth direction of TiO 2 crystal; as a result, rod-like TiO 2 crystal is obtained.

Two-photon polymerization direct laser writing (TPP DLW) is an emerging technology for producing advanced functional devices with complex three-dimensional (3D) micro-structures. Tremendous efforts have been devoted to developing two-photon polymerizable photo-sensitive nanocomposites with tailored properties. Light-induced reconfigurable smart materials such as liquid crystalline elastomers (LCEs) are promising materials. However, due to the difficulties in designing two-photon polymerizable liquid crystal monomer (LCM) nanocomposite photoresists, it is challenging to fabricate true 3D LCE micro-structures. In this paper, we report the preparation of photo-sensitive LCE nanocomposites containing photothermal nanomaterials, including multiwalled carbon nanotubes, graphene oxide and gold nanorods (AuNRs), for TPP DLW. The printability of the LCE nanocomposites is assessed by the fidelity of the micro-structures under different laser writing conditions. DLW of GO/LCM photoresist has shown a vigorous bubble formation. This may be due to the excessive heat generation upon rapid energy absorption of 780 nm laser energy. Compared to pure LCM photoresists, AuNR/LCM photoresists have a lower laser intensity threshold and higher critical laser scanning speed, due to the high absorption of AuNRs at 780 nm, which enhanced the photo-sensitivity of the photoresist. Therefore, a shorter printing time can be achieved for the AuNR/LCM photoresist.

Expanded graphite embedded with amorphous carbon-coated aluminum particle (C@Al–EG) composites were in situ synthesized by chemical vapour deposition (CVD) and ball-milling methods using EG and metallic aluminum as raw materials. Using the characterization and analysis of scanning electron microscopy, X-ray diffraction, alternating current impedance and first charge–discharge curves, the different Al contents in C@Al–EG composites were studied, and the experimental results show that the best performing content for Al was 30 wt%. The C@Al–EG composites exhibited high capacity, excellent cycle stability and rate performance as anode materials for lithium-ion batteries. At a current density of 100 mA h/g, the first reversible capacity of C@Al–EG composites was 401 mA h/g, and the decreasing speed of capacity was slow, with the specific capacity remaining at 381 mA h/g after 50 cycles. The retention rate was up to 95%.

In this study, the pressure sensitivity and temperature sensitivity of the diphasic electric conduction concrete were investigated by measuring the resistivity using the four-electrode method. The diphasic electric conduction concrete was obtained by mixing nano and micro conductive materials (carbon nanofibers, nano carbon black and steel slag powder) into the carbon fiber reinforced concrete (CFRC). The results indicated that, with the increase of conduction time, the resistivity of CFRC decreased slightly at the initial stage and then became steady, while the resistivity of CFRC containing nano carbon black had a sharp decrease at the dosage of 0.6%. With the increase of compression load, the coefficient of resistivity variation of CFRC containing nano carbon black and steel slag powder changed little. The coefficient of resistivity variation increased with the increase of steel slag powder in the dry environment, and CFRC had preferable pressure sensitivity when the mass fractions of carbon fiber and carbon nanofiber were 0.4% and 0.6%, respectively. Besides, in the humid environment, the coefficient of resistivity variation decreased with the increase of steel slag powder, and the diphasic electric conduction concrete containing 0.4% carbon fibers and 20% steel slag powder had the best pressure sensitivity under the damp environment. Moreover, in the dry environment, CFRC containing nano and micro conductive materials presented better temperature sensitivity in the heating stage than in the cooling stage no matter carbon nanofiber, nano carbon black or steel slag powder was used, especially for the CFRC containing steel slag powder.

This work investigated the effect of nanodiamond (ND) additives on the tribological properties of CrN-coated piston ring mating with the chromium-plated and BP alloy iron cylinder liners, which is one of the key friction pairs in the internal combustion engines. To enhance the dispersion of the NDs in the base oil, the surface of ND particles was modified with polyaniline via in situ polymerization. The friction and wear as well as the scuffing characteristics of the friction pair lubricated with different contents of ND composite-added base oil were evaluated by using the reciprocating tribotests, which are close to the actual conditions. The wear surface morphologies and elements distribution were analyzed to explore the wear behaviors and the associated mechanisms of friction pairs under the lubrication incorporated with the ND composites. The results show that the ND additive is beneficial for the pair of Cr liner and CrN-coated piston ring in the friction and wear as well as scuffing properties, and the best concentration of ND additive is expected to be around 1 wt%. But for the BP liner, the developed nanocomposite has a negative impact. The friction force and the wear loss of the pair lubricated by the ND composite-added oil are even worse than that tested with the base lubricating oil.

Electroactive hydrogels have received increasing attention due to the possibility of being used in biomimetics, such as for soft robotics and artificial muscles. However, the applications are hindered by the poor mechanical properties and slow response time. To address these issues, in this study, supramolecular ionic polymer–carbon nanotube (SIPC) composite hydrogels were fabricated via in situ free radical polymerization. The polymer matrix consisted of carbon nanotubes (CNTs), styrene sulfonic sodium (SSNa), β-cyclodextrin (β-CD)-grafted acrylamide, and ferrocene (Fc)-grafted acrylamide, with the incorporation of SSNa serving as the ionic source. On applying an external voltage, the ions accumulate on one side of the matrix, leading to localized swelling and bending of the structure. Therefore, a controllable and reversible actuation can be achieved by changing the applied voltage. The tensile strength of the SIPC was improved by over 300%, from 12 to 49 kPa, due to the reinforcement effect of the CNTs and the supramolecular host–guest interactions between the β-CD and Fc moieties. The inclusion of CNTs not only improved the tensile properties but also enhanced the ion mobility, which lead to a faster electromechanical response. The presented electro-responsive composite hydrogel shows a high potential for the development of robotic devices and soft smart components for sensing and actuating applications.

Based on field geological surveys of two deep-water sedimentary outcrops in the Yanchang formation of the Ordos Basin, X-ray diffraction analysis, elemental geochemical analysis, and polarizing microscope observations were conducted to investigate the causes of various sedimentary structures inside the massive sand bodies from deep-water debris flow. A genesis model of deep-water debris-flow sandstone is established: during the handling of the mass transport complexes in the basin slope, the soft sandy sedimentary layer with relatively strong shear resistance tears the soft muddy sedimentary layer with weak shear resistance and pulls various clumps inside the muddy layer. Finally, debris-flow massive sandstones with rich sedimentary structures are formed. Through argon ion polishing and field emission scanning electron microscopy, the debris-flow sandstones mainly develop micron-scale pores, and the pore radius is mainly distributed in the range of 1–8 µm. The sedimentary rocks from the semi-deep lake to deep lake facies only have a small number of nano-scale pores, and the pore radius is distributed between 20 and 120 nm. Graphical Abstract

In this study, the influence of nano-CaCO 3 (NC) and nano-SiO 2 (NS) on engineering properties of cementitious composites reinforced with polyvinyl alcohol (PVA) fibers was investigated including slump and fracture properties as well as compressive, flexural, tensile, and strengths. The influence mechanism of NS content on properties of cementitious composites was revealed. The combined effects of NS and NC were evaluated on the composites made with 0.9% volumetric PVA fiber addition. The experimental results showed that the addition of nanoparticles decreased the workability of fresh cementitious composites reinforced with PVA fibers. Higher NS content deceased more workability and NC reduced more workability than NS for the composites. There was an initial increase and later decrease in compressive and flexural strengths as NS content alters from 0% to 2.5%, while the continuous increase was found in tensile strength. 1.5% NS maximally increased compressive strength and flexural strength, while 2.5% NS is optimal for tensile strength. The composite containing NC exhibited lower strengths than the composite containing the same content of NS. The fracture energy, initiation, and unstable fracture toughness slightly increased with the NS content varying from 0% to 1.5%, while they reduced when NS content was higher than 1.5%. The effects of NS and NC on fracture energy and toughness were inapparent. The failure mode of PVA fibers in the tensile strength test was changed from pull-out to fracture with the addition of NS based on microstructure characterization.

In this study, band gaps of SH-waves (horizontally polarized shear waves) propagating in a thermal-sensitive viscoelastic matrix are investigated. Metallic films acting as heat sources are periodically embedded into the matrix, which establishes a periodically inhomogeneous thermal field. The homogenous matrix is therefore transformed into functionally gradient phononic crystals (PCs). A three-parameter solid model is employed to describe the viscoelasticity of the present matrix. By virtue of a transfer matrix method incorporated within a laminated model, the dispersion equation of SH-waves is finally obtained, from which the band gaps are determined. The transmission spectra of a finite-periodic PC are also solved to validate the band gaps. In numerical examples, the influences of incident angles of SH-waves and viscoelasticity of matrix on band gaps are discussed first. Then the research focuses on the means to tune the band gaps by manipulating the inputted powers of heat sources. Numerical examples demonstrate that such a strategy is effective and convenient in tuning the positions and widths of band gaps. A viscous parameter, i.e., the ratio of initial-state to final-state storage moduli, significantly affects the band locations and bandwidths, while the locations of low-order band gaps hardly move with the incident angle of SH-waves. Band gaps of several orders are expected to locate in lower-frequency domain, and the total bandwidth becomes larger as the inputted heat flux increases. This paper lays theoretical foundation to manufacture viscoelastic functionally graded PCs which can be used in frequency-selective devices. Graphical abstract

Bamboo particle (BP)-reinforced poly(lactic acid) (PLA) biocomposites were fabricated. The effect of the BP particle size distribution on the pyrolysis and mechanical properties of PLA biocomposites was evaluated. The optimum particle size of BP for improving the tensile strength PLA biocomposites is 200 mesh (16.6–84.5 µm). The pyrolysis mechanism and kinetics were studied according to the Coats–Redfern method. The addition of BP inhibited the pyrolysis process of PLA. The activation energy of biocomposites ranged from 120.7 to 151.5 kJ/mol, which is significantly higher than that of the neat PLA. The pyrolysis mechanisms of biocomposites are attributed to the chemical reaction at low pyrolysis temperature (270–400℃) and ash layer diffusion control at high pyrolysis temperature (400–600℃). Crystallization behavior of biocomposites showed that small BPs in PLA biocomposites generated more cross-linking points in the PLA matrix, which constrained the movement of the molecular chain and acted as an effective nucleating agent in promoting the crystallization process. The pyrolysis behavior and mechanical properties analysis provide critical information for potential large-scale production of the PLA biocomposites. Graphical abstract

To achieve an efficient conductive network while preserving the properties of carbon nanofillers is a challenging and essential issue for the fabrication of highly conductive polymeric nanocomposites. The present paper reports a facile approach to manipulate the network formation in the polymer matrix via introducing the tetrapod ZnO whisker (T-ZnO) in the carbon nanotube (CNT)-reinforced epoxy composite. The influence of T-ZnO on the CNT dispersion was evaluated by UV-Vis spectroscopy, rheological measurement, scanning electron microscopy (SEM), and electrical and mechanical properties of the bulk composite. The results showed that the CNTs tend to disperse more uniformly with an increase in T-ZnO loading. An optimized ratio of 1:2 between CNTs and T-ZnO was found to significantly enhance the electrical conductivity by 8 orders of magnitude. A low percolation threshold of 0.25 wt% CNTs was achieved in this hybrid CNTs/T-ZnO composite, which is only 40% of the threshold value in the pure CNTs/epoxy. The flexural strength and modulus of the hybrid composite were also improved noticeably in comparison to the CNTs/epoxy. The mechanism for increasing the performance of the nanocomposite was analyzed. These results indicated that the T-ZnO can assist to efficiently improve the dispersion and the formation of the conductive network, which is beneficial to the enhancement of the mechanical and electrical performance of the nanocomposite.

High-density WC–Ni composite ceramics were prepared by cold isostatic pressing–vacuum pressureless sintering–hot isostatic pressing with tungsten carbide (WC) powder and NiCl 2 ·6H 2 O as a binder. Results show that with an increase in the contents of Ni in the metal binder phase, the relative density of WC–Ni composite ceramics is improved, and the formation of the carbon-deficient W 2 C phase is reduced. There is no W 2 C generated in the WC–1 wt% Ni material. At high temperatures, the Ni phase changes into the liquid phase and enters between the WC particles, thereby promoting the close alignment of the WC particles. Moreover, the WC particles will be more closely aligned under their own surface tension and capillary action, thereby promoting the densification of WC–Ni composite ceramics. The WC–0.5 wt% Ni composite ceramics are fully dense and show the best comprehensive performance with a microhardness of 23.0 GPa, a fracture toughness of 5.28 MPa m 1/2 , and a flexural strength of 1,396.58 MPa. WC–Ni composite ceramics are mainly composed of elongated triangular prism WC particles and Ni phase. Transgranular fracture was the main fracture mode of WC–Ni multiphase ceramic materials with a small amount of intergranular fracture due to the existence of the Ni phase. Such a fracture mode can increase the flexural strength of the composite material. Graphical abstract

CdS/TiO 2 composite photocatalysts were made by the method of secondary ball milling at different ball milling speeds, milling time, and material ratios. After the secondary ball milling process, parts of the samples were calcined at high temperatures. X-ray diffraction (XRD) and UV-Vis diffuse reflectance spectroscopy (DRS) were used to observe the powder particle size, structural defect, bandgap, and absorption spectrum of the samples. Combined with the observation results, the effects of ball milling speed, time, material ratio, and high-temperature calcination on the photocatalytic performance of CdS/TiO 2 composite samples were analyzed. Furthermore, the methyl orange (MO) was chosen to simulate pollutants, and the photocatalytic degradation rate of CdS/TiO 2 composite photocatalysts for MO was evaluated under sunlight and UV irradiation conditions. The photocatalytic degradation efficiency of CdS/TiO 2 photocatalyst under UV irradiation is much higher than that under sunlight irradiation. The experimental results reveal that secondary ball milling can effectively promote the formation of CdS/TiO 2 composite nanostructure and the high-temperature calcination can reduce the bandgap width, which makes the samples easier to be excited. When the ball milling speed, time, and material ratio were respectively 400 rpm, 10 h, 25:75, and then calcined at high temperature, after 2 h of irradiation under UV light, CdS/TiO 2 composite photocatalysts exhibited maximum photocatalytic degradation efficiency of 57.84%.

In the past decade, biomimetic calcium phosphate (CaP) ceramics have been considered as practicable grafts and biomaterial substitutes in repairing jaw bone defect after tumor resection or traffic accident. Nowadays, increasing incidence of biomedical material-associated infection has raised a concern when applying these materials. In this work, a new porous CaP scaffold with antibacterial coating was proposed. This biomimetic scaffold was composited with berberine (BBR), Ag nanoparticles (nAg), and silk fibroin (SF). The microstructures and phase composition of the scaffolds were analyzed. The cytocompatibility and osteogenic potential of the prepared samples were evaluated in vitro . The scaffolds held hierarchical structure: the first-level porous CaP ceramic with micron pores ranged from 250 to 600 µm; the second-level spongy-like structure with abundant capillary pores ranged from 500 nm to 10 µm; and the third-level structure was achieved by filling BBR, nAg, and SF gel coatings into the above porous structures. The experimental results showed that the antimicrobial capability of single BBR coating is inconspicuous. However, the introduction of nAg could significantly promote the antibacterial effect of scaffolds. At the same time, such scaffolds showed improved osteoinductivity. This new biomimetic CaP scaffold with antibacterial and osteoinductive properties may be a promising candidate for bone tissue engineering.

In this study, nonequiatomic Co 28.5 Cr 21.5 Fe 20 Ni 26 Mo 4 medium-entropy alloys (MEAs) were prepared using hot isostatic pressing. The effect of annealing heat treatment on microstructure and mechanical properties of MEAs was investigated. The results showed that the microstructure of as-sintered alloys was mainly composed of the face-centered cubic (FCC) phase and μ phase. The presence of the μ phase could improve the compressive strength of Co 28.5 Cr 21.5 Fe 20 Ni 26 Mo 4 MEAs. Meanwhile, the ductile FCC phase matrix could effectively suppress the propagation of cracks to improve its ductility. Hence, as-sintered MEAs possessed excellent compression properties, and the average compressive strength value was 2,606 MPa when the strain was 50%. Compared with as-sintered MEAs, the phase composition of as-annealed MEAs did not change. The micro-hardness of annealed MEAs was stable compared to as-sintered MEAs (342 HV), and its fluctuation was about ±30 HV. The compressive strength of the annealed MEAs did not alter greatly, and the maximum fluctuation value was only about 6.5%. Hence, Co 28.5 Cr 21.5 Fe 20 Ni 26 Mo 4 MEAs had excellent thermal stability. Graphical Abstract

Chromium nitride coatings prepared by physical vapour deposition (PVD) show high hardness, high strength and good thermal conductivity, which makes them useful for cutting and forming tools. In this article, the microstructure and corrosion resistance of multilayer Cr/CrN coatings deposited by arc evaporation and hybrid high power impulse magnetron sputtering (hybrid HIPIMS) after oxidation between 500 and 800°C were examined. The average thickness of the coatings was about 3.5 µm. By means of the surface morphology analysis, elemental energy spectrometry and potentiodynamic polarization tests, the performances of the two groups of coatings have been compared. The results revealed that the coating deposited by the hybrid HIPIMS has stronger binding force with substrate, fewer surface defects and a denser structure. Also, the hybrid HIPIMS coatings have a better oxidation resistance and a better corrosion resistance compared to the arc evaporated coatings.

Hierarchical structures have attracted considerable interest due to their super-oleophobic/super-hydrophobic behavior. However, it is rare to present a novel additive manufacturing (AM) approach to fabricate hierarchical metal structures (HMSs). A micro/nano mixture ink was deposited on a substrate and a laser was used to selectively scan the ink layer. A new layer of ink was deposited on the previous consolidation layer during manufacturing. The surfaces of the as-sintered HMSs exhibit inherently super-hydrophilic and super-oleophobic behavior with a 155° contact angle (CA) with oil. Furthermore, the HMSs were successfully turned into super-hydrophobic and super-oleophilic mode (with a 152° CA) after surface modification with a solvent-free, electrostatic polytetrafluoroethylene particle deposition. They can be used as oil/water separation media by the functional surfaces existing in the pore channels. The experimental study of HMSs shows an effective removal of oil contaminants from water. The developed process also possesses an advantage of AM of HMSs with complex shapes in ambient air under the protection of an organic ink. Importantly, the present approach could be extended to a vast number of HMSs, for the preparation of highly durable functional materials for various applications.

The article describes an experimental study on the bond–slip performance between the pultruded glass fiber-reinforced polymer (GFRP) tube and the nano-CaCO 3 concrete. Taking the nano-CaCO 3 concrete strength and GFRP tube thickness as primary parameters, nine specimens were designed and tested to study the influence of these parameters on the bond strength of the specimens. Besides, three specimens filled with the ordinary concrete were also tested by using the push-out tests to make comparisons with the bond performance of the specimens filled with nano-CaCO 3 concrete. A total of four push-out tests were conducted on each specimen. The experimental results indicate that there are two types of axial load–slip curves for each specimen in four push-out tests. Moreover, comparison of the results of the push-out tests in the same direction shows that the bond failure load of the specimen decreases with the increase in the number of push-out tests. Based on the analysis of the test results, it is shown that the bond performance between the GFRP tube and the nano-CaCO 3 concrete is better than that between the GFRP tube and the ordinary concrete. Furthermore, as the nano-CaCO 3 concrete strength increases, the bond strength of the specimens decreases, indicating that the concrete strength has a negative effect on the bond strength. When the nano-CaCO 3 concrete strength is relatively smaller (C20), the bond strength of the specimens decreases with the increase in the thickness of the GFRP tube. However, when the nano-CaCO 3 concrete strength is relatively larger (C30 and C40), the bond strength of the specimens increases as the thickness of the GFRP tube increases.

To solve the bio-inertness of widely used polypropylene (PP) mesh for treating pelvic floor dysfunction (PFD), a novel strategy of incorporation with elastin gene-transfected bone marrow stem cells (BMSCs) and antibacteria drug-loaded polylactic acid (PLA) nanofibrous mat covering layer was proposed to overcome the limitation of the pristine PP mesh. Then, a series of physicochemical and in vitro experiments were applied to investigate the improvement of the as-prepared material. The elastin protein expression was proved to be upregulated without obvious cytotoxicity influence after the gene transfection and also improved the cell migration rate. In addition, the antibacteria drug-loaded PLA nanofibrous mat on the PP mesh could efficiently inhibit bacteria and showed no significant impact on cell adhesion and proliferation. Thus, we believe that the incorporation of the elastin gene-transfected BMSCs and nanofiber-coated PP mesh would be a potential candidate in the application of female PFD.

Ag nanoparticles/Mo–Ag alloy films with different Ag contents were prepared on polyimide by magnetron sputtering. The effects of Ag contents on the microstructure of self-grown Ag nanoparticles/Mo–Ag alloy films were investigated using XRD, FESEM, EDS and TEM. The Ag content plays an important role in the size and number of uniformly distributed Ag nanoparticles spontaneously formed on the Mo–Ag alloy film surface, and the morphology of the self-grown Ag nanoparticles has changed significantly. Additionally, it is worth noting that the Ag nanoparticles/Mo–Ag alloy films covered by a thin Ag film exhibits highly sensitive surface-enhanced Raman scattering (SERS) performance. The electric field distributions were calculated using finite-difference time-domain analysis to further prove that the SERS enhancement of the films is mainly determined by “hot spots” in the interparticle gap between Ag nanoparticles. The detection limit of the Ag film/Ag nanoparticles/Mo–Ag alloy film for Rhodamine 6G probe molecules was 5 × 10 −14  mol/L. Therefore, the novel type of the Ag film/Ag nanoparticles/Mo–Ag alloy film can be used as an ideal SERS-active substrate for low-cost and large-scale production.

Functionalized graphene-based nanocomposites have opened new windows to address some challenges for increasing the sensitivity, accuracy and functionality of biosensors. Polyaniline (PANI) is one of the most potentially promising and technologically important conducting polymers, which brings together the electrical features of metals with intriguing properties of plastics including facile processing and controllable chemical and physical properties. PANI/graphene nanocomposites have attracted intense interest in various fields due to unique physicochemical properties including high conductivity, facile preparation and intriguing redox behavior. In this article, a functionalized graphene-grafted nanostructured PANI nanocomposite was applied for determining the ascorbic acid (AA) level. A significant current response was observed after treating the electrode surface with methacrylated graphene oxide (MeGO)/PANI nanocomposite. The amperometric responses showed a robust linear range of 8–5,000 µM and detection limit of 2 µM ( N = 5). Excellent sensor selectivity was demonstrated in the presence of electroactive components interfering species, commonly found in real serum samples. This sensor is a promising candidate for rapid and selective determination of AA.

To explore the spectral radiation characteristics of carbon nanofibers, a finite-difference time-domain method has been applied to study and calculate the scattering/absorption factors of carbon nanofibers with various arrangements, while the filler contents are 61.15%, 53.81%, 48.92%, 44.03% and 39.13% in the spectrum band of 2.5–15 µm. The effects of the nanofiber content, 2D/3D random arrangement and nanofiber radius on scattering/absorption characteristics have been analyzed. The analytical results show that the spectral radiation characteristics of carbon nanofibers have been significantly increased with an increase in the filler content. When the nanofiber content reduced to 48.92%, the random arrangement structure of carbon nanofiber plays an essential role in determining the spectral radiation characteristics. Analytical results prove that the prediction accuracy has been significantly improved by 30.12% by sing the 3D random arrangement model than by using the 2D uniform arrangement model. This study proposed a 3D model to predict the spectral radiation characteristics of carbon nanofibers and their aggregates in engineering nanocomposites.

Nano-materials modified cement-based materials have attracted wide attention due to their advantages of improving strength and durability. In this paper, the effect of nano-SiO 2 (NS) with particle sizes of 15 and 50 nm on the mechanical properties and microstructure of cement paste was studied. The results showed that 50 nm NS provided a greater compressive strength than that of 15 nm NS, while 15 nm NS afforded a denser microstructure than that of 50 nm NS. A fluctuation in the compressive strength was revealed using a physicochemical reaction equation, and the microstructure was interpreted by a pore structure analysis. In addition, the orientation index of calcium hydroxide (CH) with 15 nm NS could be reduced significantly in the early stages (the early stages refer to the first three days from the maintaining of specimens) compared with when the 50 nm NS was used. The experimental results also showed that NS helped increase the mechanical strength of cement paste, advance the endothermic peak of CH, and refine the size of the CH crystals. The microstructural changes at different stages of cement paste with different particle sizes of NS were investigated by X-ray diffraction, scanning electron microscopy, mercury intrusion porosimetry and differential thermal analysis. This study is expected to promote the research and application of nano-materials in the cement industry by clarifying the performance of NS with different particle sizes. Graphical abstract

Although Fe–N/C catalysts have received increasing attention in recent years for oxygen reduction reaction (ORR), it is still challenging to precisely control the active sites during the preparation. Herein, we report Fe x N@RGO catalysts with the size of 2–6 nm derived from the pyrolysis of graphene oxide and 1,1′-diacetylferrocene as C and Fe precursors under the NH 3 /Ar atmosphere as N source. The 1,1′-diacetylferrocene transforms to Fe 3 O 4 at 600°C and transforms to Fe 3 N and Fe 2 N at 700°C and 800°C, respectively. The as-prepared Fe x N@RGO catalysts exhibited superior electrocatalytic activities in acidic and alkaline media compared with the commercial 10% Pt/C, in terms of electrochemical surface area, onset potential, half-wave potential, number of electrons transferred, kinetic current density, and exchange current density. In addition, the stability of FGN-8 also outperformed commercial 10% Pt/C after 10000 cycles, which demonstrates the as-prepared Fe x N@RGO as durable and active ORR catalysts in acidic media.

Uniform and continuous Al 2 O 3 thin films were prepared by the chemical liquid deposition (CLD) method. The breakdown field strength of the amorphous CLD-Al 2 O 3 film is 1.74 MV/cm, making it could be used as a candidate dielectric film for electronic devices. It was further proposed to use the CLD-Al 2 O 3 film as an electron blocking layer in a triboelectric nanogenerator (TENG) for output performances enhancement. Output voltages and currents of about 200 V and 9 µA were obtained, respectively, which were 2.6 times and 3 times, respectively, higher than TENG device without an Al 2 O 3 . A colloidal condensation-based procedure controlled by adjusting the pH value of the solution was proposed to be the mechanism of CLD, which was confirmed by the Tyndall effect observed in the growth liquid. The results indicated that the CLD could serve as a low-cost, room temperature, nontoxic and facile new method for the growth of functional thin films for semiconductor device applications.

Acrylic acid-modified polyhedral oligomeric silsesquioxane (AC-POSS) was synthesized by the reaction between the amine groups in polyhedral oligomeric silsesquioxane (POSS) and acrylic acid, which could dissolve in water and can be easily purified. Free-radical copolymerization was applied to synthesize azobenzene liquid crystalline polymer silsesquioxane (LCP-POSS) with different proportions of AC-POSS and liquid crystalline monomers. The trans -isomers of azobenzene moieties in LCP-POSS were gradually transformed to cis -isomers with increasing ultraviolet irradiation time. The photoisomerization reaction of liquid crystalline polymer (LCP) and LCP-POSS showed the first-order dynamic reaction. Compared with the LCP, the photoisomerization rate constant of LCP-POSS was decreased due to the space steric hindrance of the POSS as a rigid segment. The phase transition temperature of liquid crystalline in LCP-POSS increased with increasing POSS content, and the liquid crystalline texture in LCP-POSS became smaller under the polarized light. With further increasing the POSS content (>50 wt%) in LCP-POSS, the ordered structure of the liquid crystalline phase was gradually affected, resulting in one-way liquid crystal (LC) phase behavior. The synthesized LCP-POSS has LC properties, light-responsive properties, and thermal stability. When the POSS is introduced into the LC material, the phase state of the LC material will become more abundant and the LC phase will become more stable. The significance of this study is to develop and extend its applications as stimuli-responsive materials and devices.

Oil leak from vehicles is one of the most common pollution types of the road. The spilled oil could be retained on the surface and spread in the air voids of the road, which results in a decrease in the friction coefficient of the road, affects driving safety, and causes damage to pavement materials over time. Photocatalytic degradation through nano-TiO 2 is a safe, long-lasting, and sustainable technology among the many methods for treating oil contamination on road surfaces. In this study, the nano-TiO 2 photocatalytic degradation effect of road surface oil pollution was evaluated through the lab experiment. First, a glass dish was used as a substrate to determine the basic working condition of the test; then, a test method considering the impact of different oil erosion degrees was proposed to eliminate the effect of oil erosion on asphalt pavement and leakage on cement pavement, which led to the development of a lab test method for the nano-TiO 2 photocatalytic degradation effect of oil pollution on different road surfaces.

A pairwise coupling of 0D Super-P (SP), 1D carbon nanotubes (CNTs), and 2D graphene nanosheets (GNs) into binary carbon-based conductive additives was used here for the LiFePO 4 cathode in lithium-ion batteries. For comparison, the LiFePO 4 cathode with SP, CNT, or GN unitary conductive agent was also examined. Electrochemical test results suggest that the cathodes with binary conducting additives present greatly improved electrochemical performance than the traditional cathode system (only SP used). Especially, the LiFePO 4 cathode containing 3% CNT component exhibits the highest specific capacity and the best cycling stability among all the cathodes with binary conducting additives, indicating that an appropriate amount of CNTs is critical in enhancing the conductivity and practical capacity output. However, an excess of CNTs leads to entangling with each other, hampering the uniform distribution of active materials and resulting in poor electrode performance. Furthermore, the combination of CNT and GN can effectively improve the capacity and cycling stability of the LiFePO 4 cathodes due to the synergistic effect of 3D conductive networks constructed by the two.

Sub-µm CaCO 3 (calcite; CC) particles were converted to calcium monohydrogenphosphate dihydrate (DCPD) and hydroxyapatite (HAp) via soaking treatments in K 2 HPO 4 solutions with varied pH (3–12) and concentrations (0.1–1.5 M) at 37°C for up to 10 days. DCPD was derived from the solutions with pH ≤ 6; while hollow HAp was yielded when pH ≥ 7 in assemblies of petal-like crystallites. Results of magic angle spinning (MAS) and cross-polarization magic angle spinning (CP-MAS) NMR studies have shown that the HAp lattice has only PO 4 2− but no HPO 4 2− at B (phosphate) sites. Trace amounts of CO 3 2− have occupied both A (OH) and B (PO 4 ) sites, and H 2 O is adsorbed on surface crystallites. The primary crystallite size of HAp derived from Scherrer equation increases quickly in a 12 h period and becomes gradually stable afterward. Samples of particles soaked within 3 h in a temperature range of 20–80°C were analyzed by X-ray diffraction. It is shown that the rate constant of 1 M solution is about an order of magnitude greater than that of 0.1 M solution and the apparent activation energy is 33 kJ/mol. In this work, the conversion of CC to HAp can be quantitatively controlled to solve the problem of slow degradation of HAp. Graphical abstract

At the nanolevel, a classical continuum approach seems to be inapplicable to evaluate the mechanical behaviors of materials. With the introduction of scale parameter, the scale effect can be reasonably described by the modified continuum theory. For boron nitride nanotubes (BNNTs), the scale effect can be reflected by the curvature and the dangling bonds at both ends, mainly the former for a slender tube. This study aims to achieve a good capability of classical Euler–Bernoulli theory to directly predict the bending behaviors of single-walled BNNTs without introducing scale parameters. Elastic properties of BNNTs involving the scale effect have been first conducted by using an atomistic-continuum multiscale approach, which is directly constructed based on the atomic force field. The well-determined hexagonal boron nitride sheet is inherited in the present study of single-walled BNNTs which can be viewed as rolling up a boron nitride sheet into a seamless hollow cylinder. Euler–Bernoulli theory solution of bending deflection on the basis of the present thickness is found to be much closer to the atomistic-continuum simulation results than the commonly used interlayer space. Case studies with different tubular lengths, radii and constraints are investigated, and from which the yielded scattered scale parameters in modified continuum theories are discussed.

This article studies two different sputtering methods for depositing Ag–Mo and Ag–Zr alloy films on single crystal silicon (Si), flexible polyimide (PI) and soda-lime glass substrates. The phase structure and the surface morphology of the Ag–Mo(Zr) alloy films were characterized by XRD, SEM and EDS. The effects of substrate properties and sputtering methods on the self-grown Ag particles on the Ag–Mo(Zr) alloy films were investigated. As the result of the experiment, nanoscale Ag particles were formed on the surface of Ag–Mo(Zr) alloy films. However, the size and the number of self-formed Ag particles on the Ag–Mo(Zr) alloy film on the PI substrate are significantly different from that on the Si substrate and glass substrate. This outcome is closely related to the different thermal stress evolution behaviors of the alloy films on different substrates during annealing.

Three nano-CaCO 3 (NC) replacement levels of 1, 2, and 3% (by weight of cement) were utilized in autoclaved concrete. The accelerated carbonation depth and Coulomb electric fluxes of the hardened concrete were tested periodically at the ages of 28, 90, 180, and 300 days. In addition, X-ray diffraction, thermogravimetry, and mercury intrusion porosimetry were also performed to study changes in the hydration products of cement and microscopic pore structure of concrete under autoclave curing. Results indicated that a suitable level of NC replacement exerts filling and accelerating effects, promotes the generation of cement hydration products, reduces porosity, and refines the micropores of autoclaved concrete. These effects substantially enhanced the carbonation and chloride resistance of the autoclaved concrete and endowed the material with resistances approaching or exceeding that of standard cured concrete. Among the three NC replacement ratios, the 3% NC replacement was the optimal dosage for improving the long-term carbonation and chloride resistance of concrete.

To study the effect of improved adsorption property of tetrapod-like ZnO (T-ZnO) on its photocatalytic performance, a new composite was prepared by loading silica aerogels (SiO 2 (AG)) on the surface of T-ZnO via the sol–gel method. Various characterization methods showed that SiO 2 (AG) was uniformly loaded on the surface of T-ZnO, and the morphology as well as structural characteristics of SiO 2 (AG) and T-ZnO were not changed. Nitrobenzene (NB) was selected as the model pollutant, and the adsorption and photocatalytic properties of T-ZnO and SiO 2 (AG)/T-ZnO for NB were studied. The photocatalytic degradation processes of NB using T-ZnO and SiO 2 (AG)/T-ZnO followed the first-order reaction. Considering the initial moment reaction kinetic, the photocatalytic kinetic of SiO 2 (AG)/T-ZnO and T-ZnO was consistent with the Langmuir–Hinshelwood kinetic model, and reaction rate constant k SiO 2 AG / T-ZnO ′ > k T-ZnO ′ {k}_{{\text{SiO}}_{2}\left(\text{AG}\right)/\text{T-ZnO}}^{^{\prime} }\gt {k}_{\text{T-ZnO}}^{^{\prime} } , adsorption rate constant K ad SiO 2 ( AG ) / T-ZnO {K}_{\text{ad}{\text{SiO}}_{2}(\text{AG})/\text{T-ZnO}} > K ad T-ZnO , which demonstrated that SiO 2 (AG) loading could increase T-ZnO adsorption to NB, then promoted its photocatalytic performance.

Electron beam irradiated sheep wool with absorbed radiation doses ranging from 0 to 165 kGy showed good adsorption properties toward copper cations. The Cu( ii ) being Lewis acid generated several types of complex salts based on carboxylates or cysteinates with ligands available in keratin. Under these conditions, cross-links were formed between the keratin chains. Experimental data obtained from Cu( ii ) adsorption using the concentration of 800–5,000 mg/L were tested for fitting to 10 isotherm models. Various compositions and architectures of the Cu( ii )-complexes were specified to be responsible for different isotherm model fittings. The copper cation showed adherence to Langmuir, Flory–Huggins, and partially Redlich–Peterson models. The latter clearly distinguished the native wool from the modified ones. Another aim is to investigate the conditions for the adsorption of anti-microbial nanoparticles in addition to the redox-active metals on radiation-modified wool taking into account that the diffusion of nanoparticles into the modified wool is governed by electrostatic interactions.

High belite cement has a wide application potential due to its low energy consumption, low CO 2 emission, and excellent durability performance. Due to the low hydration rate and strength development at an early age, the activation of beta-dicalcium silicate (β-C 2 S) crystallographic structure is essential to improve the early strength of high belite cement. In this study, the β-C 2 S phase is activated by dissolving Ba 2+ ions into the crystal lattice to improve the hydration rate. Unlike the traditional analysis methods of thermodynamics and dynamics theory, the first principle and density functional theory were applied to study the effect of Ba 2+ ions on the activation of β-C 2 S, especially on the crystallographic structure, lattice parameters, and electronic structure change. The crystallographic structure of β-C 2 S can be activated by doping Ba atom and the crystal formation energy increases and the bandgap between VBM and CBM become narrow in the activated β-C 2 S crystallographic structure. Comparing the Ca 2+ substitution in [CaO 6 ] or [CaO 8 ], the lattice deformation and hydraulic reactivity is more significant in Ba 2 -C 2 S and Ba 22 -C 2 S. The first principle and density functional theory explains the change of the electronic structure of the activated crystallographic structure and provides a theoretical basis for the purposeful design of material structures. Graphical abstract

In this article, environmental friendly BAg25Cu40Zn34Sn (BAg-25) and BAg30Cu37Zn32Sn (BAg-30) flux-core solder metal capable of facilitating automatic production of brazing manufacturing processes were prepared. The butt and lap induction brazing tests were carried out on the substrate with BAg-25 and BAg-30. Wettability, microstructure and mechanical properties of the solders on the base metal were studied by field emission scanning electron microscope (SEM-EDS), electron backscattering diffraction (EBSD), tensile testing machine and microhardness tester. Results indicated that the wetting property of BAg-30 with 30% silver content was better than that of BAg-25 with 25% silver content. At the same time, besides copper and silver-based solid solutions, the brazed joint of BAg-30 solder also contain Cu + Ag eutectic phase. In the brazed joint of BAg-25 solder, the grain size is smaller, which makes the tensile strength and the shear strength of the joints better. Therefore, the BAg-25 flux-core solder metal will further reduce the industrial cost and meet the requirements of mechanical properties.

We report, for the first time to our knowledge, on the polymer nanocomposite sunlight spectrum down-converters made by the concurrent multi-beam multi-target pulsed laser deposition (CMBMT-PLD) of phosphor and polymer in ambient air. Phosphor PLD targets were made of down-converting rare-earth (RE)-doped fluorides NaYF 4 :Yb 3+ ,Er 3+ , and NaYF 4 :Yb 3+ ,Tm 3+ with a Stokes shift of 620 nm (from 360 to 980 nm), minimizing the effect of re-absorption. The phosphors were synthesized by the wet method. Polymer target was made of poly (methyl methacrylate) known as PMMA. Target ablation was conducted with 1,064 nm beams from an Nd:YAG Q-switched laser. Beam intensity was 2.8 × 10 16  W/cm 2 for both targets. The substrate was a microscope glass slide. Phosphor nanoparticles with a size ranging from 10 to 50 nm were evenly distributed in the polymer matrix during deposition. The nanoparticles retained the crystalline structure and the fluorescent properties of the phosphor target. There was no noticeable chemical decomposition of the deposited polymer. The products of laser-induced reaction of the polymer target with atmospheric gases did not reach the substrate during PLD. Post-heating of the substrate at ∼90°C led to fusion of separate polymer droplets into uniform coating. Quantum yield of the down-conversion polymer nanocomposite film was estimated to be not less than ∼5%. The proposed deposition method can find its application in making commercial-size down-converter coatings for photo-voltaic solar power applications.

Hardened layers are commonly required for automotive components after their production using a machining process in order to enhance the service life of these components. This study investigates the possibility of producing a nanostructured machined surface which can increase the hardness of the machined surface by varying the machining parameters under cryogenic conditions in end milling of AISI 4340. The end milling experiments were performed using multi-layered TiAlN- and AlCrN-coated carbide. Prior to the experiment, a finite element method (FEM) was used to simulate the cutting temperature generated and it had been found that at cutting speed of 200–300 m/min, feed rate of 0.15–0.3 mm/tooth, axial depth of cut of 0.3–0.5 mm, and radial depth of cut of 0.2–0.35 mm, the temperature generated can be sufficiently high to cause austenitic transformation. A field emission scanning electron microscope (FESEM) equipped with angle selective backscattered (AsB) detection analysis was used to investigate the microstructure and machined-affected layers of the machined surfaces. The crystallographic orientation/phase change and nano-hardness were analysed through X-ray diffraction (XRD) and a nano-hardness testing machine. The results showed that the cryogenic machining had significantly affected the surface integrity characteristics of the AISI 4340 alloy due to refined microstructure, favourable phase structure, and higher hardness near the surface layer. The results of this study may be useful in providing an insight into a potential technological shift from conventional surface case hardening processes to the present technique. Graphical abstract

Braided composite stent (BCS), woven with nitinol wires and polyethylene terephthalate (PET) strips, provides a hybrid design of stent. The mechanical performance of this novel stent has not been fully investigated yet. In this work, the influence of five main design factors (number of nitinol wires, braiding angle, diameter of nitinol wire, thickness and stiffness of the PET strip) on the surface coverage, radial strength, and flexibility of the BCS were systematically studied using computational models. The orthogonal experimental design was adopted to quantitatively analyze the sensitivity of multiple factors using the minimal number of study cases. Results have shown that the nitinol wire diameter and the braiding angle are two most important factors determining the mechanical performance of the BCS. A larger nitinol wire diameter led to a larger radial strength and less flexibility of the BCS. A larger braiding angle could provide a larger radial strength and better flexibility. In addition, the impact of the braiding angle decreased when the stent underwent a large deformation. At the same time, the impact of the PET strips increased due to the interaction with nitinol wires. Moreover, the number of PET strips played an important role in the surface coverage. This study could help understand the mechanical performance of BCS stent and provides guidance on the optimal design of the stent targeting less complications.

The effect of different cinnamon essential oil (CEO) contents on flammability, thermal stability and morphological characteristics of nanocellulose fibre–reinforced starch biopolymer composites was studied. This sugar palm nanocellulose reinforced with sugar palm starch, containing 0–2% CEO, was prepared through solution casting technique. From scanning electron microscopy analysis, the cross-sections of the CEO-containing films showed appearance of micro-porous spots as micro-porous holes because of the occurrence of partial evaporation on the cryo-fractured surface as a result of the vacuum condition. Increment in CEO concentration resulted in increasing trend of the number and size of the micro-porous holes. Significant increase was observed in the thermal stability with the CEO loading when compared with neat composites. Besides that, increasing CEO loading also resulted in decrement of linear burning rate of the composites.

In this study, a high-energy ball mill was used to composite nano-TiO 2 and CdS, and three kinds of nanocomposite photocatalysts TiO 2 , CdS/TiO 2 -R400, and CdS/TiO 2 -R600 were prepared, which can respond to visible light. The photocatalytic concrete test block was prepared by mixing the nanocomposite photocatalyst and other masses with cement by incorporation method. To study the effect of the photocatalyst content on the photocatalytic performance of nanoconcrete, a total of four catalyst contents (0, 2%, 5%, and 8%) were set. The effects of high-temperature treatment (400°C) and different light sources (ultraviolet and visible light) on photocatalytic efficiency were also considered. The results show that the catalytic efficiency of CdS/TiO 2 -R400 under two light sources is higher than that of the other two photocatalysts. Compared to ultraviolet light sources, the photocatalytic efficiency of CdS/TiO 2 nanocomposite concrete under visible light is lower, and the efficiency is below 9%. The optimal amounts of CdS/TiO 2 nanocomposite photocatalyst under ultraviolet and visible light are 2% and 5%, respectively. The high-temperature treatment can improve the photocatalytic performance of CdS/TiO 2 nanocomposite photocatalyst by 2% to 3%. Graphical abstract

The electrospray deposition method was used to deposit carbon nanotubes (CNT) onto the surfaces of woven carbon fiber (CF) to produce woven hybrid carbon fiber–carbon nanotubes (CF–CNT). Extreme high-resolution field emission scanning electron microscopy (XHR-FESEM), X-ray diffraction (XRD), Raman spectroscopy and Fourier transform infrared spectroscopy (FT-IR) were used to analyze the woven hybrid CF–CNT. The results demonstrated that CNT was successfully and homogenously distributed on the woven CF surface. Woven hybrid CF–CNT epoxy composite laminates were then prepared and compared with woven CF epoxy composite laminates in terms of their flexural and dielectric properties. The results indicated that the flexural strength, flexural modulus and dielectric constant of the woven hybrid CF–CNT epoxy composite laminates were improved up to 19, 27 and 25%, respectively, compared with the woven CF epoxy composite laminates.

Development of stretchable wearable devices requires essential materials with high level of mechanical and electrical properties as well as scalability. Recently, silicone rubber-based elastic polymers with incorporated conductive fillers (metal particles, carbon nanomaterials, etc.) have been shown to the most promising materials for enabling both high electrical performance and stretchability, but the technology to make materials in scalable fabrication is still lacking. Here, we propose a facile method for fabricating a wearable device by directly coating essential electrical material on fabrics. The optimized material is implemented by the noncovalent association of multiwalled carbon nanotube (MWCNT), carbon black (CB), and silicon rubber (SR). The e-textile sensor has the highest gauge factor (GF) up to 34.38 when subjected to 40% strain for 5,000 cycles, without any degradation. In particular, the fabric sensor is fully operational even after being immersed in water for 10 days or stirred at room temperature for 8 hours. Our study provides a general platform for incorporating other stretchable elastic materials, enabling the future development of the smart clothing manufacturing.

In this work, a strain-based degradation model was implemented and validated to better understand the dynamic interactions between the bioresorbable vascular scaffold (BVS) and the artery during the degradation process. Integrating the strain-modulated degradation equation into commercial finite element codes allows a better control and visualization of local mechanical parameters. Both strut thinning and discontinuity of the stent struts within an artery were captured and visualized. The predicted results in terms of mass loss and fracture locations were validated by the documented experimental observations. In addition, results suggested that the heterogeneous degradation of the stent depends on its strain distribution following deployment. Degradation is faster at the locations with higher strains and resulted in the strut thinning and discontinuity, which contributes to the continuous mass loss, and the reduced contact force between the BVS and artery. A nonlinear relationship between the maximum principal strain of the stent and the fracture time was obtained, which could be transformed to predict the degradation process of the BVS in different mechanical environments. The developed computational model provided more insights into the degradation process, which could complement the discrete experimental data for improving the design and clinical management of the BVS.

An easy and facile hydrothermal method is presented to synthesize hybrid materials of hollow mesoporous Zn 0.76 Co 0.24 S nanospheres anchored on reduced graphene oxide (rGO) sheets (Zn 0.76 Co 0.24 S@N/S-rGO), in which the obtained Zn 0.76 Co 0.24 S nanospheres are composed of numerous nanoparticles. Being evaluated as anode materials for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs), the Zn 0.76 Co 0.24 S@N/S-rGO composites exhibited a high reversible capacity of 804 and 605 mA h g −1 at the current density of 1 A g −1 after 500 cycles for LIBs and SIBs, respectively. The excellent electrochemical performance of Zn 0.76 Co 0.24 S@N/S-rGO composites originates from the synergistic effect between hollow Zn 0.76 Co 0.24 S nanospheres and reduction graphene, as well as the void spaces between the neighbouring nanoparticles of Zn 0.76 Co 0.24 S providing large contact areas with electrolyte and buffer zone to accommodate the volume variation during the cycling process.

Despite the development of pharmacy, there are still incurable diseases for which the medicine has not been found yet. Because many diseases are asymptomatic in their first stage of development, often early detection is the crucial factor in combating them. The article describes the process of synthesis of carbon nanotubes (CNTs) which can be useful in medical diagnostics. CNTs were synthesized by chemical vapor deposition. The obtained material was subjected to functionalization – attaching fluorescent markers. In order to check the usefulness of the obtained structures in diagnostics, their fluorescent properties were examined. The results of fourier transform infrared spectroscopy thermogravimetric analysis and scanning electron microscopy prove that, after proper functionalization, CNTs could be used as fluorescents markers.

High molar mass materials (nano-silica slurry [NSS] and aggregate of steel furnace slag [ASFS]) can improve concrete shielding properties. However, only a few studies have been reported in this regard. Hence, this paper aims to determine the effect of NSS and ASFS on the properties of the resulting steel slag heavyweight concrete (SSHWC). The use of NSS in this study is a novel contribution. Furthermore, the maximum percentage of NSS to be introduced into the concrete for maximum effect was also optimized. This study also implemented an investigation program with six concrete mixtures prepared using ASFS as the primary by-product aggregate. The engineering, X-ray, and γ-ray attenuation characteristics of the SSHWC were evaluated. The results showed that the addition of NSS in SSHWC at the optimal content of 3% by weight of cement improved the X-ray shielding by 6.4%. Besides, all the concrete’s engineering and γ-rays’ properties were enhanced correspondingly.

Commercial LiFePO 4 (LFP) electrode still cannot meet the demand of high energy density lithium-ion batteries as a result of its low theoretical specific capacity (170 mA h g −1 ). Instead of traditional electrochemical inert polyvinylidene fluoride (PVDF), the incorporation of multifunctional polymeric binder becomes a possible strategy to overcome the bottleneck of LFP cathode. Herein, a novel polyimide (PI) binder was synthesized through a facile hydrothermal polymerization route. The PI binder exhibits better connection between active particles with uniform dispersion than that of PVDF. The multifunctional PI binder not only shows well dispersion stability in the organic electrolyte, but also contributes to extra capacity because of the existence of electrochemical active carbonyl groups in the polymer chain. Besides, the high intrinsic ion conductivity of PI also results in promoted ion transfer kinetic. Consequently, the LFP cathode using PI binder (LFP–PI) shows larger capacity and better rate capability than LFP cathode with PVDF binder (LFP–PVDF). Meanwhile, the superior binding ability also endows LFP–PI with great cycling stability compared to the LFP–PVDF electrode.

The Cu–20 wt% Ag alloy wire rod was prepared using three-chamber vacuum cold mold vertical continuous up-casting followed by multi-pass continuous drawing. The evolution of microstructure, mechanical property, and electrical property of the Cu–20 wt% Ag alloy wire during multi-pass continuous drawing was studied. After multi-pass continuous drawing, the continuous network eutectic structure in the longitudinal section of the as-casted rod was gradually drawn into long fibers that approximately parallel to the axial direction, while the space of the continuous network eutectic structure in the transverse section is getting smaller and smaller. Both the preferred orientation of copper and silver grains are (1,1,1). With the increase of drawing strain ( η ), the tensile strength of Cu–20 wt% Ag alloy wire gradually increases while the elongation gradually decreases. When the diameter is drawn to 0.02 mm ( η = 11.94), the tensile strength of the alloy is 1,682 MPa and elongation is 2.0%. The relationship between tensile strength, elongation, and diameter conforms to Allometric and Boltzmann functions, respectively.

This work proposes an approach to fabricate flexible transparent ultraviolet (UV)-shielding membrane by casting method, which uniformly disperses pristine zinc oxide nanoparticles (NPs) in low-density polyethylene (LDPE). The critical conditions for film fabrication, such as casting temperature, LDPE concentration in the solution, dissolution time, NP concentration, and post hot press cooling processes, are systematically studied. It is found that the casting temperature needs to be close to the melting temperature of LDPE, namely, 115°C, so that transparent film formation without cracks can be guaranteed. NP agglomerates are suppressed if the polymer concentration is controlled below 6%. For good dispersion of NPs, LDPE has to be swelled or unentangled enough in the solution (close to 200 h dissolution time), and then the NP agglomerates can be diminished due to the diffusion of the NPs into the polymer gel (322 h dissolution time). When the NPs are well-dispersed in the LDPE film, the film can completely shield UV light while allowing high transmissivity for the visible light. As the concentration of NPs in the film increases from 4 to 6%, the transmissivity of the film decreases, the tensile strength increases, and the tensile failure strain decreases.

Droplet microfluidic was devoted to design and fabricate robust devices in the field of biosensing, tissue engineering, drug delivery, cell encapsulation, cell isolation, and lab-on-a-chip. Chitosan was widely used for different biomedical applications because of its unique characteristics such as antibacterial bioactivities, immune-enhancing influences, and anticancer bioactivities. In this research, a model is used for investigating the formation and size of composite droplets in a microfluidic device. The role of the velocity flow ratio in the composite droplet characteristics such as the generation rate and composite droplet size is described. According to the results, a desirable protocol is developed to control the properties of the composite droplets and to compare the size and rate of the composite droplets in a micro device. Furthermore, the level set laminar two-phase flow approach is exploited for studying the composite droplet-breaking procedure. An experimental procedure is used for validation of the simulation process. Various sizes and geometries of the composite droplets are fabricated to depict a potential in biomedical applications such as bioimaging, biosensing, tissue engineering, drug delivery, cell encapsulation, cancer cell isolation, and lab-on-a-chip.

Water and sand were used as the medium of multiwall carbon nanotube (MCNT) and prepared MCNT aqueous suspension and MCNT suspension-coated sand, respectively; afterwards, they were introduced into cement mortar (MNT/CM, MNTSM), respectively. Next, mechanical strengths and piezoresistive properties (DC resistivities ( ρ v ), AC impedances ( Z r )) under cyclic loadings ( σ c ) of two types of MNT/CM and MNTSM nanocomposites were investigated to explore the intrinsic and self-sensing behaviors. Results reveal that MCNT can be evenly and well-coated on sand, which favors to achieve its intrinsic self-sensing property. Although the fraction changes in ρ v and Z r under the same σ c of MNTSM are both lower than those of MNT/CM, the stress sensitivity of MNTSM is only −1.16%/MPa (DC resistivity), −1.55%/MPa (AC impedance); its sensing linearity and stability (2.53, 2.45%; 2.73, 2.67%) are superior to those of MNT/CM (4.94, 2.57%; 3.78, 2.96%). Piezoresistivity using AC impedance technique is helpful to acquire balanced sensing sensitivity and stability while applied as intrinsic sensors in infrastructure.

In this work, an attempt is done to apply the eigenvalue approach as well as Donnell thin-shell theory to find out the vibrational analyses of an irregular single-walled carbon (ISWCNT) incorporating initial stress effects. The effects of surface irregularity and initial stresses on natural frequency of vibration of nano materials, especially for single-walled carbon nanotubes (SWCNTs), have not been investigated before, and most of the previous research have been carried for a regular and initial stress-free CNTs. Therefore, it must be emphasized that the vibrations of prestressed irregular SWCNT are novel and applicable for the design of nano oscillators and nanodevices, in which SWCNTs act as the most prevalent nanocomposite structural element. The surface irregularity is assumed in the parabolic form at the surface of SWCNT. A novel equation of motion and frequency equation is derived. The obtained numerical results provide a better representation of the vibration behavior of prestressed ISWCNTs. It has been observed that the presence of either surface irregularity or initial stress has notable effects on the natural frequency of vibration, particularly in the short-length SWCNTs. Numerical results show that the natural frequency of SWCNT decreases with increase in surface irregularity and initial stress parameters. To the authors’ best knowledge, the effect of surface irregularity and initial stresses on the vibration behavior of SWCNTs has not yet been studied, and the present work is an attempt to find out this effectiveness. In addition, the results of the present analysis may serve as useful references for the application and the design of nano oscillators and nanodevices, in which SWCNTs act as the most prevalent nanocomposite structural element.

This paper was focused on application of the perlite mineral as the filler for polymer nanocomposites in technical applications. A strong effect of the perlite nano-filler on high-density poly(ethylene) (HDPE) composites’ mechanical and thermal properties was found. Also found was an increase of the Young’s modulus of elasticity with the increasing filler concentration. Increased stiffness from the mechanical tensile testing was confirmed by the nondestructive vibrator testing as well. This was based on displacement transmissibility measurements by means of forced oscillation single-degree-of freedom method. Fracture toughness showed a decreasing trend with increasing perlite concentration, suggesting occurrence of the brittle fracture. Furthermore, ductile fracture processes were observed as well at higher filler concentrations by means of SEM analysis. There was also found relatively strong bonding between polymer chains and the filler particles by SEM imagining.

Indium tin oxide (ITO) is the most important transparent conducting electrode to date and the candidate for ultrafast signal processing in telecommunication region. ITO is normally selectively removed in a multiple-steps process for device application. In this work, we aimed to study single pulse removal of ITO-coated glass and PET by using a nanosecond (ns) laser (266 nm) and a femtosecond (fs) laser (1,025 nm) where each process is dominated by either linear or nonlinear process. For ns laser, ITO was removed from PET substrate at 0.01 J/cm 2 . Detachment likely occurred via thermal-induced process because of the high absorption by both ITO and PET and the thermomechanical properties of PET. At higher laser fluence (∼0.04 J/cm 2 ), the ITO films on both substrates were damaged, and at 1.34 J/cm 2 , ITO was ablated from the glass substrate. For fs laser removal via nonlinear process, ITO was removed from PET substrate at 0.3 J/cm 2 , but at 0.8 J/cm 2 , the PET substrate was also modified. ITO layer was partially removed from glass substrate by fs laser pulse at 0.3 J/cm 2 and full removal only occurred at 1.7 J/cm 2 . Thus, the fluence range for single fs pulse removal of ITO/PET was 0.3–0.8 J/cm 2 and >1.7 J/cm 2 for ITO/glass.

In this study, the effects of polyaniline (PANI) incorporation (3 wt% of PANI) and graphene nanoplatelets (GNPs) loading (0.1–0.7 wt%) on the mechanical, thermal, and electrical performance of epoxy matrix were investigated. The incorporation of 0.3 wt% GNPs optimally enhanced the bending strength, bending modulus, tensile strength, tensile modulus, and impact strength (90 MPa, 1422 MPa, 63 MPa, 602 MPa, and 8.29 kJm −2 , respectively). At 0.3 wt% GNPs, the hybridization effect optimally enhanced the glass transition behaviour of the epoxy nanocomposites. The electrical and thermal conductivities of epoxy were improved upon the inclusion of PANI, and this increase was further augmented when the GNPs content increased to 0.3 wt%. However, higher GNPs contents deteriorated the mechanical performance and electrical and heat conduction. Field emission scanning electron microscopy showed good filler distribution and effective interactions among the GNPs, PANI, and epoxy components with appropriate compositions.

The extraction of Li from the spent LiFePO 4 cathode is enhanced by the selective removal using interactions between HCl and NaClO to dissolve the Li + ion while Fe and P are retained in the structure. Several parameters, including the effects of dosage and drop acceleration of HCl and NaClO, reaction time, reaction temperature, and solid–liquid ratio on lithium leaching, were tested. The Total yields of lithium can achieve 97% after extraction process that lithium is extracted from the precipitated mother liquor, using an appropriate extraction agent that is a mixture of P507 and TBP and NF. The method also significantly reduced the use of acid and alkali, and the economic benefit of recycling is improved. Changes in composition, morphology, and structure of the material in the dissolution process are characterized by inductively coupled plasma optical emission spectrometry, scanning electron microscope, X-ray diffraction, particle size distribution instrument, and moisture analysis.

The performance of wound dressing determines the effect of wound closure and recovery. Water absorption and bacteriostasis of wound dressings play an important role in wound recovery and healing. In this study, an optimized chitosan wound dressing-tough chitosan dressing (TCS) with high water absorption, high bacteriostasis, and degradability was developed. The chemical structure of chitosan remained stable during the process of optimized treatment, and an increase in mechanical properties was obtained for the dressing. After optimization, the water absorption and antibacterial properties of the chitosan dressing were greatly improved, which is significantly better than sodium alginate dressing. The authors believe that TCS dressing with high hygroscopicity and high bacteriostasis has great potential application value in the field of wound recovery and healing.

In this work, a hybrid laminated plate is developed by changing ply orientations and stacking sequences. The hybrid laminated plate is composed of carbon nanotube reinforced composite and fiber reinforced composite layers. Negative Poisson’s ratio (NPR) is obtained for the case of [22 F /(22 C /−22 C ) 3T /−22 F ] laminate. A theoretical laminated model considering geometric nonlinearity and shear deformation is presented. Based on a two-step perturbation method, the solutions of the motion equations are obtained to capture the nonlinear frequencies and load–deflection curves. On this basis, the fourth-order Runge–Kutta method is used to obtain the dynamic response of hybrid laminated plates. The presented model is verified by comparing the results obtained analytically and numerically. Several factors such as loading and distribution of carbon nanotubes (CNTs), and foundation type are considered in parametric study. Numerical results indicate that the thermal-mechanical behavior of hybrid laminated plates significantly improved by properly adjusting the CNT distribution. In addition, the results reveal that changes in temperature and foundation stiffness have pronounced influence on the nonlinear vibration characteristics of hybrid laminate plates with NPR as compared to those with positive Poisson’s ratio.

Carbon nanomaterials, predominantly carbon nanofibers, carbon nanotubes, graphene, graphene nanoplates, graphene oxide and reduced graphene oxide, possess superior chemical, physical and mechanical properties. They have been successfully introduced into ordinary Portland cement to give enhancements in terms of mechanical properties, durability and electrical/thermal conductivity, and to modify the functional properties, converting conventional cement-based materials into stronger, smarter and more durable composites. This paper provides a comprehensive review of the properties of carbon nanomaterials, current developments and novel techniques in carbon nanomaterials enhanced cement-based composites (CN-CBCs). Further study of the applications of CN-CBCs at industrial scale is also discussed.

In recent years, with the higher requirements for the performance of cement-based materials and the call for energy conservation and environmental protection, a wave of research on new materials has set off, and various high-performance concrete and more environmentally friendly geopolymers have appeared in the public. With a view to solving the defects of energy consumption, environmental protection and low toughness of traditional cement-based materials. At the same time, nanomaterials have become a focus of current research. Therefore, the research on the properties of cement-based materials and geopolymers modified by graphene and its derivatives has aroused extensive interest of researchers. Graphene-based nanomaterials are one of them. Because of their large specific surface area, excellent physical properties have been favored by many researchers. This paper reviews the research progress of graphene-based nanomaterials in improving the properties of cement-based materials and geopolymer materials, and points out the main challenges and development prospects of such materials in the construction field in the future.

With the development of integrated circuit technology, especially after entering the sub-micron process, the reduction of critical dimensions and the realization of high-density devices, the flatness between integrated circuit material layers is becoming more and more critical. Because conventional mechanical polishing methods inevitably produce scratches of the same size as the device in metal or even dielectric layers, resulting in depth of field and focus problems in lithography. The first planarization technique to achieve application is spin on glass (SOG) technology. However, this technology will not only introduce new material layers, but will also fail to achieve the global flattening required by VLSI and ULSI technologies. Moreover, the process instability and uniformity during spin coating do not meet the high flatness requirements of the wafer surface. Also, while some techniques such as reverse etching and glass reflow can achieve submicron level regional planarization. After the critical dimension reaches 0.35 microns (sub-micron process), the above methods cannot meet the requirements of lithography and interconnect fabrication. In the 1980s, IBM first introduced the chemical mechanical polishing (CMP) technology used to manufacture precision optical instruments into its DRAM manufacturing [1]. With the development of technology nodes and critical dimensions, CMP technology has been widely used in the Front End Of Line (FEOL) and Back End Of Line (BEOL) processes [2]. Since the invention of chemical mechanical polishing, scientists have not stopped studying its internal mechanism. From the earliest Preston Formula (1927) to today’s wafer scale, chip scale, polishing pad contact, polishing pad - abrasive - wafer contact and material removal models, there are five different scale models from macro to the micro [3]. Many research methods, such as contact mechanics, multiphase flow kinetics, chemical reaction kinetics, molecular dynamics, etc., have been applied to explain the principles of chemical mechanical polishing to establish models. This paper mainly introduces and summarizes the different models of chemical mechanical polishing technology. The various application scenarios and advantages and dis-advantages of the model are discussed, and the development of modeling technology is introduced.

Nanocarbon materials (carbon nanotubes, graphene, graphene oxide, reduced graphene oxide, etc.) are considered the ideal toughening phase of ceramic matrix composites because of their unique structures and excellent properties. The strengthening and toughening effect of nanocarbon is attributed to several factors, such as their dispersibility in the matrix, interfacial bonding state with the matrix, and structural alteration. In this paper, the development state of nanocarbon-toughened ceramic matrix composites is reviewed based on the preparation methods and basic properties of nanocarbon-reinforced ceramic matrix composites. The assessment is implemented in terms of the influence of the interface bonding condition on the basic properties of ceramic matrix composites and the methods used to improve the interface bonding. Furthermore, the strengthening and toughening mechanisms of nanocarbon-toughened ceramic matrix composites are considered. Moreover, the key problems and perspectives of research work relating to nanocarbon-toughened ceramic matrix composites are highlighted.

Nanostructures are widely used in nano and micro-sized systems and devices such as biosensors, nano actuators, nano-probes, and nano-electro-mechanical systems. The complete understanding of the mechanical behavior of nanostructures is crucial for the design of nanodevices and systems. Therefore, the flexural, stability and vibration analysis of various nanostructures such as nanowires, nanotubes, nanobeams, nanoplates, graphene sheets and nanoshells has received a great attention in recent years. The focus has been made, to present the structural analysis of nanostructures under thermo-magneto-electro-mechanical loadings under various boundary and environmental conditions. This paper also provides an overview of analytical modeling methods, fabrication procedures, key challenges and future scopes of development in the direction of analysis of such structures, which will be helpful for appropriate design and analysis of nanodevices for the application in the various fields of nanotechnology.

As an emerging material, nanomaterials have attracted extensive attention due to their small size, surface effect and quantum tunneling effect, as well as potential applications in traditional materials, medical devices, electronic devices, coatings and other industries. Herein, the influence of nanoparticle selection, production process, grain size, and grain boundary structures on the mechanical properties of nanomaterials is introduced. The current research progress and application range of nano-materials are presented. The unique properties of nano-materials make them superior over traditional materials. Therefore, nanomaterials will have a broader application prospect in the future. Research on nanomaterials is significant for the development and application of materials science.

Hereby the possible applications of oxide nanoparticles in the cancer diagnostics and therapy are presented. Cancer diseases are nowadays one of the most common causes of death in the highly-developed countries. Discussed will be the current clinical cancer detection methods with their shortcomings. The role of nanomedicine in cancer medicine and the potential applications of nanoparticles debated in the literature will be critically evaluated. In the second part, the most common methods for the nanoparticle synthesis will be discussed. Finally, the system for cancer detection based on the enhanced permeation-retention of multimodal high-k oxide nanoparticles doped with lanthanides will be proposed for both for themagnetic resonance imaging (non-gadolinium contrast agents) and for fluorescence guided biopsy and surgery.

The behavior of cement-based materials is manipulated by chemical and physical processes at the nanolevel. Therefore, the application of nanomaterials in civil engineering to develop nano-modified cement-based materials is a promising research. In recent decades, a large number of researchers have tried to improve the properties of cement-based materials by employing various nanomaterials and to characterize the mechanism of nano-strengthening. In this study, the state of the art progress of nano-modified cement-based materials is systematically reviewed and summarized. First, this study reviews the basic properties and dispersion methods of nanomaterials commonly used in cement-based materials, including carbon nanotubes, carbon nanofibers, graphene, graphene oxide, nano-silica, nano-calcium carbonate, nano-calcium silicate hydrate, etc. Then the research progress on nano-engineered cementitious composites is reviewed from the view of accelerating cement hydration, reinforcing mechanical properties, and improving durability. In addition, the market and applications of nanomaterials for cement-based materials are briefly discussed, and the cost is creatively summarized through market survey. Finally, this study also summarizes the existing problems in current research and provides future perspectives accordingly.

Immunotherapy, which utilizes the patient’s own immune system to fight against cancer, further results in durable antitumor responses and reduces metastasis and recurrence, has become one of the most effective and important cancer therapies along with surgery, radiotherapy, and chemotherapy. Nanomaterials with the advantages of large specific surface, delivery function, and controllable surface chemistry are used to deliver antigens or adjuvants, or both, help to boost immune responses with the imaging function or just act as adjuvants themselves and modulate tumor microenvironment (TME). In this review, recent development and applications of nanomaterials for cancer immunotherapy including delivery systems based on nanomaterials, uniting imaging, self-adjuvants, targeting functions, artificial antigen presenting cells, and TME modulation are focused and discussed.

Adipose tissue reconstruction is an important technique for soft tissue defects caused by facial plastic surgery and trauma. Adipose tissue reconstruction can be repaired by fat transplantation and biomaterial filling, but there are some problems in fat transplantation, such as second operation and limited resources. The application of advanced artificial biomaterials is a promising strategy. In this paper, injectable biomaterials and three-dimensional (3D) tissue-engineered scaffold materials for adipose tissue reconstruction in plastic surgery are reviewed. Injectable biomaterials include natural biomaterials and artificial biomaterials, which generally have problems such as high absorptivity of fillers, repeated injection, and rejection. In recent years, the technology of new 3D tissue-engineering scaffold materials with adipose-derived stem cells (ADSCs) and porous scaffold as the core has made good progress in fat reconstruction, which is expected to solve the current problem of clinical adipose tissue reconstruction, and various biomaterials preparation technology and transformation research also provide the basis for clinical transformation of fat tissue reconstruction.

Emerging nanomaterials provide an invaluable opportunity for the development of cementitious materials. Many scholars have explored the influence of graphene (GP) and graphene oxide (GO) on the performance of the cementitious materials. This article reviews the previous research on the effect of GP and GO on the properties of cementitious materials. Detailed review of the mechanical properties and durability of cementitious materials containing GP or GO nanofilms is presented, and the mechanism is discussed. The mechanical properties of GO-cementitious materials are significantly enhanced. The optimal improvement of GO-modified compressive, flexural, and tensile strengths is 77.3%, 78.3%, and 78.6%, respectively. The durability of GO- and GP-modified cementitious material is compared with the control group. The incorporation of GP or GO significantly improves the sulfate attack resistance, and the transport properties can be decreased, while the frost resistance of GO- and GP-modified cementitious materials needs further research. This literature review shows that the microstructure of GO- and GP-modified cementitious material is improved in three aspects: accelerating the cement hydration, refining the pore structure, and hindering the crack propagation.

Triboelectric nanogenerators (TENGs) have attracted much attention as energy harvesting and sensor devices. Compared with experimental means, theoretical analysis is of low cost and time-saving for behavior prediction and structural optimization and is more powerful for understanding the working mechanism of TENGs. In this article, the theoretical system for performance simulation of TENGs has been reviewed systematically. The parallel-plate capacitor model, the distance-dependent electric field (DDEF) model, figures of merit (FOMs), and multi-parameter analysis are introduced. The parallel-plate capacitor model is the most fundamental model of TENGs, which is used to simulate the output of TENGs with planar configurations. For non-planar TENGs, the DDEF model is proposed, according to which the electric field is assumed to be distance-dependent rather than being uniform throughout the space. Further, to realize the standardization of TENGs, a series of FOMs are proposed as the standardized evaluation tools for TENGs’ output performance, which are used to reflect the influence of device parameters on the output from different aspects. Lastly, the multi-parameter analysis is introduced to consider the impact of multiple parameters on the output of TENGs simultaneously. These theories constitute the theoretical simulation system of TENGs, which could be used to guide the experimental work on TENGs and boost device optimization in commercial manufacturing.

Diamondoids are cage-like hydrocarbon materials with unique characteristics such as low dielectric constants, negative electron affinity, large steric bulk, and electron-donating ability. They are widely used for advanced functional materials in nanocomposite science. Surface modification of diamondoids also produces functional derivatives that broaden its applications. This article provides a concise review of the fundamentals of diamondoids, including their origin and functionalization, electronic structure, optical properties, and vibrational characteristics. The recent advances of diamondoids and their derivatives in applications, such as nanocomposites and thin film coatings, are presented. The fabrication of diamondoid-based nanostructured devices, including electron emitters, catalyst sensors, and light-emitting diodes, are also reviewed. Finally, the future developments of this unique class of hydrocarbon materials in producing a novel nanostructure system using advanced nanotechnologies are discussed. This review is intended to provide a basic understanding of diamondoid properties, discuss the recent progress of its modifications and functionalization, and highlight its novel applications and future prospects.

The rapidly increasing number of mobile devices, voluminous data, and higher data rate is pushing the development of the fifth-generation (5G) wireless communications. The 5G networks are broadly characterized by three unique features: ubiquitous connectivity, extremely low latency, and very high-speed data transfer via adoption of new technology to equip future millimeter band wireless communication systems at nanoscale and massive multi-input multi-output (MIMO) with extreme base station and device densities, as well as unprecedented numbers of nanoantennas. In this article, these new technologies of 5G are presented so as to figure out the advanced requirements proposed for the nanomaterials applied to antennas in particular. Because of massive MIMO and ultra-densification technology, conventional antennas are unable to serve the new frequency for smaller sizes, and the nanoantennas are used in 5G. The nanomaterials for nanoantennas applied in wideband millimeter waves are introduced. Four types of nanomaterials including graphene, carbon nanotubes, metallic nanomaterials, and metamaterials are illustrated with a focus on their morphology and electromagnetic properties. The challenges for the commercialization of 5G and nanomaterials are also discussed. An atomistic modeling approach is proposed for the development of novel nanomaterials applied in 5G and beyond. Graphical abstract

Recent advances in biomedicine largely rely on the development in nanoengineering. As the access to unique properties in biomaterials is not readily available from traditional techniques, the nanoengineering becomes an effective approach for research and development, by which the performance as well as the functionalities of biomaterials has been greatly improved and enriched. This review focuses on the main materials used in biomedicine, including metallic materials, polymers, and nanocomposites, as well as the major applications of nanoengineering in developing biomedical treatments and techniques. Research that provides an in-depth understanding of material properties and efficient enhancement of material performance using molecular dynamics simulations from the nanoengineering perspective are discussed. The advanced techniques which facilitate nanoengineering in biomedical applications are also presented to inspire further improvement in the future. Furthermore, the potential challenges of nanoengineering in biomedicine are evaluated by summarizing concerned issues and possible solutions. Graphical abstract

A sustainable power source is more and more important in modern society. Ocean wave energy is a very promising renewable energy source, and it is widely distributed worldwide. But, it is difficult to develop efficiently due to various limitations of the traditional electromagnetic generator. In recent years, the newly developed triboelectric nanogenerator (TENG) provides an excellent way to convert water wave energy into electrical energy, which is mainly based on the coupling between triboelectrification and electrostatic induction. In this paper, a review is given for recent advances in using the TENG technology harvesting water wave energy. We first introduce the four most fundamental modes of TENG, based on which a range of wave energy harvesting devices have been demonstrated. Then, these applications’ structure and performance optimizations are discussed. Besides, the connection methods between TENG units are also summarized. Finally, it also outlines the development prospects and challenges of technology.

Chromium (Cr) is a common toxic heavy metal that is widely used in all kinds of industries, causing a series of environmental problems. Nanoscale zero- valent iron (nZVI) is considered to be an ideal remediation material for contaminated soil, especially for heavy metal pollutants. As a material of low toxicity and good activity, nZVI has been widely applied in the in situ remediation of soil hexavalent chromium (Cr( vi )) with mobility and toxicity in recent years. In this paper, some current technologies for the preparation of nZVI are summarized and the remediation mechanism of Cr( vi )-contaminated soil is proposed. Five classified modified nZVI materials are introduced and their remediation processes in Cr( vi )-contaminated soil are summarized. Key factors affecting the remediation of Cr( vi )-contaminated soil by nZVI are studied. Interaction mechanisms between nZVI-based materials and Cr( vi ) are explored. This study provides a comprehensive review of the nZVI materials for the remediation of Cr( vi )-contaminated soil, which is conducive to reducing soil pollution.

The growth of the application of electronic devices has created a new form of pollution known as noise or radio frequency interference, electromagnetic radiation, or electromagnetic interference (EMI), which results in the malfunction of equipment. A new carbon-based polymer composite has been unlocked through the discovery of polymer composites. Carbon nanotubes (CNTs) have shown potential as reinforcement fillers in polymer to enhance an EMI shielding material owing to their large specific surface area, well-defined 3D networking structure, and unique electronic structure. The main focus of this review is the role of CNT as fillers in intrinsic conducting polymer and conducting polymer composite. The factors that influence EMI shielding performance are also included in this review. The roles of the size; shape; and electronic, mechanical, and chemical properties of nanomaterials in tuning the EMI shielding effectiveness of polymer hybrid are emphasized. The structural design of CNT polymer composite has been reviewed as well. Future research direction has been proposed to overcome the current technological limitations and realize the most advanced EMI shielding materials for future use. The composites have a potential to replace traditional shielding materials owing to their advantageous properties.

The use of functional material can help mitigate the pollution by heavy metals, which presents an array of risks to human production and life. This work provides a comprehensive review of the current knowledge on functionalized layered double hydroxide (LDH) as a heavy metal absorption material, by synthesizing the information from a total of 141 relevant publications published since 2005. LDH provides a potentially highly efficient method to adsorb heavy metal ions, which is simple to prepare and of low cost. The lack of functional groups and structural components of pristine LDH, however, limits the absorption capacity and widespread applications of LDH. Through intercalation, surface modification, or loading on substrates, functional groups or structural components are introduced into the pristine LDH to prepare functionalized LDH. In this process, the hydroxyl group and the valence state of [Mg(OH) 6 ] octahedrons play a crucial role. Functionalized LDH can be endowed with selective absorption capacity and enhanced stability and recyclability. After adsorbing heavy metal ions, functionalized LDH can be readily separated from the liquid phase. These aspects are discussed, along with the structure and composition, shape and size, and synthesis methods and research tools of LDH. This work concludes with the discussion of preparation and utilization and a look to the future in terms of identified research needs regarding the preparation, use, and recycling (or upcycling) of economical and environmental-friendly LDH.

Currently, advanced biomaterial design solutions often have more than two kinds of nanotechnology design strategies, but there is no suitable classification to describe these designs systematically. Based on the material design ideas and the modes of implementing functions, this article exemplifies and proposes a new nanotechnology classification that includes physical properties, the chemical reactions that respond to the microenvironment and bio-inspired incorporation. If two or more nanotechnology designs in the same classification are to be integrated into the same biological material, it is necessary to analyze the integration conflict between the designs. With the development of big data, this classification method may help researchers and artificial intelligence to realize automated integration of multiple designs and provide new material nanotechnology design integration solutions.

Natural fiber composites (NFCs) also termed as biocomposites offer an alternative to the existing synthetic fiber composites, due to their advantages such as abundance in nature, relatively low cost, lightweight, high strength-to-weight ratio, and most importantly their environmental aspects such as biodegradability, renewability, recyclability, and sustainability. Researchers are investigating in depth the properties of NFC to identify their reliability and accessibility for being involved in aircrafts, automotive, marine, sports’ equipment, and other engineering fields. Modeling and simulation (M&S) of NFCs is a valuable method that contributes in enhancing the design and performance of natural fibers composite. Recently many researchers have applied finite element analysis to analyze NFCs’ characteristics. This article aims to present a comprehensive review on recent developments in M&S of NFCs through classifying the research according to the analysis type, NFC type, model type, simulation platform and parameters, and research outcomes, shedding the light on the main applicable theories and methods in this area, aiming to let more experts know the current research status and also provide some guidance for relevant researches.

Buildings contribute to 40% of total global energy consumption, which is responsible to 38% of greenhouse gas emissions. It is critical to enhance the energy efficiency of buildings to mitigate global warming. In the last decade, advances in thermal energy storage (TES) techniques using phase change material (PCM) have gained much attention among researchers, mainly to reduce energy consumption and to promote the use of renewable energy sources such as solar energy. PCM technology is one of the most promising technologies available for the development of high performance and energy-efficient buildings and, therefore, considered as one of the most effective and on-going fields of research. The main limitation of PCM is its leakage problem which limits its potential use in building construction and other applications such as TES and textiles, which can be overcome by employing nano-/micro-encapsulation technologies. This paper comprehensively overviews the nano-/micro-encapsulation technologies, which are mainly classified into three categories including physical, physiochemical and chemical methods, and the properties of microcapsules prepared. Among all encapsulation technologies available, the chemical method is commonly used since it offers the best technological approach in terms of encapsulation efficiency and better structural integrity of core material. There is a need to develop a method for the synthesis of nano-encapsulated PCMs to achieve enhanced structural stability and better fracture resistance and, thus, longer service life. The accumulated database of properties/performance of PCMs and synthesised nano-/micro-capsules from various techniques presented in the paper should serve as the most useful information for the production of nano-/micro-capsules with desirable characteristics for building construction application and further innovation of PCM technology.

Cell adhesion is a basic requirement for anchorage-dependent cells to survive on the matrix. It is the first step in a series of cell activities, such as cell diffusion, migration, proliferation, and differentiation. In vivo , cells are surrounded by extracellular matrix (ECM), whose physical and biochemical properties and micromorphology may affect and regulate the function and behavior of cells, causing cell reactions. Cell adhesion is also the basis of communication between cells and the external environment and plays an important role in tissue development. Therefore, the significance of studying cell adhesion in vitro has become increasingly prominent. For instance, in the field of tissue engineering and regenerative medicine, researchers have used artificial surfaces of different materials to simulate the properties of natural ECM, aiming to regulate the behavior of cell adhesion. Understanding the factors that affect cell behavior and how to control cell behavior, including cell adhesion, orientation, migration, and differentiation on artificial surfaces, is essential for materials and life sciences, such as advanced biomedical engineering and tissue engineering. This article reviews various factors affecting cell adhesion as well as the methods and materials often used in investigating cell adhesion.

Hyaluronic acid (HA) is widely distributed in the human body, and it is heavily involved in many physiological functions such as tissue hydration, wound repair, and cell migration. In recent years, HA and its derivatives have been widely used as advanced bioactive polymers for bone regeneration. Many medical products containing HA have been developed because this natural polymer has been proven to be nontoxic, noninflammatory, biodegradable, and biocompatible. Moreover, HA-based composite scaffolds have shown good potential for promoting osteogenesis and mineralization. Recently, many HA-based biomaterials have been fabricated for bone regeneration by combining with electrospinning and 3D printing technology. In this review, the polymer structures, processing, properties, and applications in bone tissue engineering are summarized. The challenges and prospects of HA polymers are also discussed.

Currently, energy and environmental problems are becoming more serious. The use of solar energy to split water and produce clean, renewable hydrogen as an energy source is a feasible and effective approach to solve these problems. As the most promising semiconductor material for photocatalytic water splitting, TiO 2 -based nanomaterials have received increasing attention from researchers in academia and industry in recent years. This review describes the research progress in the theoretical calculations of TiO 2 -based photocatalysts in water splitting. First, it briefly introduces some commonly used theoretical calculation methods, the crystal structure of TiO 2 and its photocatalytic mechanism, and the principle of doping and heterojunction modification to improve the photocatalytic performance of TiO 2 . Subsequently, the adsorption state of water molecules with different coverages on the surface of TiO 2 , the rate-limiting steps of the splitting of water molecules on the surface of TiO 2 , and the transfer process of photogenerated current carriers at the interface between water molecules and TiO 2 are analyzed. In addition, a brief review of research into the theoretical calculations of TiO 2 -based commercial photocatalysts in the field of water splitting is also provided. Finally, the calculation of TiO 2 -based photocatalytic water-splitting simulations is summarized, and possible future research and development directions are discussed.

Micro/nano-fabrication technology via two-photon polymerization (TPP) nanolithography is a powerful and useful manufacturing tool that is capable of generating two dimensional (2D) to three dimensional (3D) arbitrary micro/nano-structures of various materials with a high spatial resolution. This technology has received tremendous interest in cell and tissue engineering and medical microdevices because of its remarkable fabrication capability for sophisticated structures from macro- to nano-scale, which are difficult to be achieved by traditional methods with limited microarchitecture controllability. To fabricate precisely designed 3D micro/nano-structures for biomedical applications via TPP nanolithography, the use of photoinitiators (PIs) and photoresists needs to be considered comprehensively and systematically. In this review, widely used commercially available PIs are first discussed, followed by elucidating synthesis strategies of water-soluble initiators for biomedical applications. In addition to the conventional photoresists, the distinctive properties of customized stimulus-responsive photoresists are discussed. Finally, current limitations and challenges in the material and fabrication aspects and an outlook for future prospects of TPP for biomedical applications based on different biocompatible photosensitive composites are discussed comprehensively. In all, this review provides a basic understanding of TPP technology and important roles of PIs and photoresists for fabricating high-precision stimulus-responsive micro/nano-structures for a wide range of biomedical applications.

Microchannel heat sink (MCHS) is an advanced cooling technique to fulfil the cooling demand for electronic devices installed with high-power integrated circuit packages (microchips). Various microchannel designs have been innovated to improve the heat transfer performance in an MCHS. Specifically, the utilisation of nanotechnology in the form of nanofluid in an MCHS attracted the attention of researchers because of considerable enhancement of thermal conductivity in nanofluid even at a low nanoparticle concentration. However, a high-pressure drop was the main limitation as it controls the MCHS performance resulted from heat transfer augmentation. Therefore, this study aimed to critically summarise the challenges and limitations of both single and hybrid passive methods of MCHS. Furthermore, the performance of nanofluid as a coolant in the MCHS as affected by the type and concentration of nanoparticle and the type of base fluid was reviewed systematically. The review indicated that the hybrid MCHS provides a better cooling performance than MCHS with the single passive method as the former results in a higher heat transfer rate with minimal pressure drop penalty. Besides that, further heat transfer performance can be enhanced by dispersing aluminium dioxide (Al 2 O 3 ) nanoparticles with a concentration of less than 2.0% (v/v) in the water-based coolant.

The choosing of micromechanical environment is very important for the growth of bone-related cells. In this paper, bovine cancellous bone slices with 3D porous structures were used for 3D culturing of MC3T3-E1 cells (Mouse embryo osteoblast precursor cells) through a four-point-bending device due to their good biocompatibility and strength. Effects of micromechanical environment on the growth of MC3TC-E1 cells were investigated by immunofluorescent staining and alkaline phosphatase analysis, and the most positive microporous structures were found. In addition, a model of cell density vs stress was established through a specific normalization method and finite element simulation. The results showed that the micromechanical environment of the bone slices promoted cell proliferation, and the detail influence of stress on cell proliferation could be described by the mathematical model, which could provide a theoretical basis for the design of micromechanical environment in the bone tissue engineering scaffolds to stimulate cell proliferation.

At present, high-sensitivity, high-penetration-depth, and accurate tissue resolution clinical imaging effect are required, while computer transverse scanning, microwave imaging, and fluorescence imaging (FL) cannot meet the requirements of clinical imaging, but the magnetic resonance imaging (MRI) can meet the requirements of clinical dissecting details. The effect of MRI imaging is closely related to the contrast agent (CA). As an important type of CA, Fe 3 O 4 and its analogues have been widely concerned because of their low toxicity and relatively low price. In this review, we summarize the development and improvement of CAs based on Fe 3 O 4 and its analogues from T 2 imaging mode and development limitation in the initial single modulus imaging mode, to T 1 imaging mode overcoming the limitations of T 2 imaging and the limitations of its own in application, to the later development of dual modulus imaging form, and to the current multi-modulus imaging form. Simultaneously, we demonstrate the research progress, preparation methods, and future trends based on Fe 3 O 4 and its analogues CAs for MRI, the current application status is preliminarily summarized, and the future development trend is prospected.

Graphene is an advanced carbon functional material with inherent unique properties that make it suitable for a wide range of applications. It can be synthesized through either the top–down approach involving delamination of graphitic materials or the bottom–up approach involving graphene assembly from smaller building units. Common top–down approaches are exfoliation and reduction while bottom–up approaches include chemical vapour deposition, epitaxial growth, and pyrolysis. A range of materials have been successfully used as precursors in various synthesis methods to derive graphene. This review analyses and discusses the suitability of conventional, plant- and animal-derived, chemical, and fossil precursors for graphene synthesis. Together with its associated technical feasibility and economic and environmental impacts, the quality of resultant graphene is critically assessed and discussed. After evaluating the parameters mentioned above, the most appropriate synthesis method for each precursor is identified. While graphite is currently the most common precursor for graphene synthesis, several other precursors have the potential to synthesize graphene of comparable, if not better, quality and yield. Thus, this review provides an overview and insights into identifying the potential of various carbon precursors for large-scale and commercial production of fit-for-purpose graphene for specific applications.

Nanofluid is a colloidal mixture consisting of nano-sized particles dispersed in a liquid medium. It improves heat transfer properties and promotes high energy efficiency in a wide spectrum of engineering applications. In recent years, particularly in the automotive industry, the addition of nanofluid in diesel/biodiesel as an additive for ICE has become an attractive approach to promote enhanced combustion efficiency and emission reduction due to their superior thermophysical properties. Many researchers have previously demonstrated that the addition of nanoparticles in diesel/biodiesel fuel improved the overall engine combustion characteristics. As a whole, this study aims to summarize the recent research findings related to the effect of nanoparticles on the fuel properties and engine combustion efficiency. Furthermore, different types of additive blended with varying fuel properties are also compared and discussed. Lastly, the advantages and prospects of using nanofluid as an additive fuel are summarized for future research opportunities.

Recently, photocatalysis technology has been widely considered as an effective method for solving environmental pollution issues and addressing the energy crisis. Hybrids of layered double hydroxide (LDH) exhibit excellent photocatalytic properties for use in the field of wastewater treatment due to the large interlayer spaces, chemical stability, and low cost. However, pristine LDH suffers from numerous limitations, such as insufficient visible light utilization and a high recombination rate of electron–hole pairs, resulting in degradation of photocatalytic performance. Recent advancements have demonstrated that LDH-based hybrids are suitable nanocomposites for photocatalytic applications when combining LDH with other semiconductors. This article summarizes the progress in the field of LDH-based ternary composites with emphasis on the removal of organic pollutants and heavy metal ions from aqueous media. Moreover, the applications and synthesis of LDH-based ternary composites, including corresponding examples, are discussed. In addition, the interaction mechanisms between photocatalysts and contaminants in water are comprehensively explained. Finally, the review provides insights into the challenges and prospects for the advancement of LDH-based photocatalysts.

Functionally graded carbon nanotube-reinforced composite (FG-CNTRC) is a novel nanomaterial; the mechanical behavior of FG-CNRC has become a hot topic in the Materials Science and Engineering Science recently, thanks to its excellent mechanical and electrical properties after its fusion with matrix. In this paper, the review efforts for research progress on the modeling and analysis of FG-CNTRC structures are carried out. Firstly, the development background of FG-CNRC is presented, as well as some basic theories and main equations for mechanical analysis of FG-CNTRC structure. Then, the mechanical behaviors of FG-CNTRC beams, plates, and shells under loading conditions are comprehensively reviewed, with the emphasis on discussing the bending, buckling, and vibration behaviors of the structures. Finally, the future research orientation of the field is considered and prospected.

In the recent decades, traditional concrete poses a great challenge to the modernization of the construction industry because of low tensile strength, poor toughness, and weak resistance to cracking. To overcome these problems, ultra-high performance concrete (UHPC) with superior mechanical properties and durability is developed for broad application prospect in the future engineering construction. However, UHPC is less eco-friendly because it consumes more cement compared with the traditional concrete. The manufacturing of cement produces large amounts of carbon dioxide and therefore leads to the greenhouse effect. Nanomaterials consist of microstructural features that range from 0.1 to 100 nm in size, which exhibit the novel properties different from their bulk counterparts, including filling effect, surface activity, and environmental sustainability. This paper reviews the effect of various nanomaterials used in UHPC to partially replace the cement or as an additive on the microstructures, mechanical properties, and other properties of UHPC. In addition, the limitations and shortcomings of the current research are analyzed and summarized, and development directions are provided for future research on the application of nanomaterials in UHPC.

Skin cancer (SC) is the most common carcinoma affecting 3 million people annually in the United States and millions of people worldwide. It is classified as melanoma SC (MSC) and non-melanoma SC (NMSC). NMSC represents approximately 80% of SC and includes squamous cell carcinoma and basal cell carcinoma. MSC, however, has a higher mortality rate than SC because of its ability to metastasize. SC is a major health problem in the United States with significant morbidity and mortality in the Caucasian population. Treatment options for SC include cryotherapy, excisional surgery, Mohs surgery, curettage and electrodessication, radiation therapy, photodynamic therapy, immunotherapy, and chemotherapy. Treatment is chosen based on the type of SC and the potential for side effects. Novel targeted therapies are being used with increased frequency for large tumors and for metastatic disease. A scoping literature search on PubMed, Google Scholar, and Cancer Registry websites revealed that traditional chemotherapeutic drugs have little effect against SC after the cancer has metastasized. Following an overview of SC biology, epidemiology, and treatment options, this review focuses on the mechanisms of advanced technologies that use silver nanoparticles in SC treatment regimens.

Over the last decade, nickel nanoparticles (NiNPs) have been investigated for various potential applications due to their superior ferromagnetic properties such as magneto-crystalline anisotropy, high coercive forces, and chemical stability. Therefore, there has been a tremendous enhancement in the synthesis techniques, proposed reaction mechanisms, and applications of NiNPs. This paper presents a recent overview of the synthesis, reaction mechanisms, and applications of NiNPs. NiNPs in the size range of 1–100 nm are synthesized by various methods for research and commercial applications. The synthesis techniques are classified into three main types, namely, top-down, bottom-up, and hybrids of top-down and bottom-up protocols including solvothermal, physical, and chemical approaches. The detailed reaction mechanisms in the formation of NiNPs, especially for biosynthesis techniques, are extensively described. Trends in NiNP applications in fields such as biomedical, catalysis, supercapacitors, and dye-sensitized solar cells are explored. The basic advantages and role of NiNPs as a catalyst for various reactions are illustrated here. Graphical abstract

Superparamagnetic nanoparticles, exposed to an external variable magnetic field, undergo rapid excitation/relaxation. So-called soft magnets, typically iron-based, rapidly and completely relax when the magnetic field returns to zero. Instead, cobalt-based (CoB) hard magnets retain residual magnetization, a characteristic related with the procedure for nanoparticles (NPs) production. Many researchers are still attracted by the potential of CoB NPs for theranostics as multifaced signal probes for imaging, microrobots, enhanced thermo/radiation therapy, and drug release. Since iron oxide NPs are the only magnetic NPs approved for human use, they are of reference for analyzing the potential of the disregarded CoB NPs. In vitro observed toxicity of CoB NPs, largely attributable to cobalt ions and other chemical species released by dissolution, excluded them from further investigations in humans. Nevertheless, experimental evidences documenting the in vivo toxicity of engineered CoB NPs remain very few. The surface functionalization adds newer properties and could improve the biocompatibility of NPs, critical for the clinical exploitation. In our opinion, it would be worth to further exploit the potential of finely tunable properties of CoB NPs in in vivo systems in order to establish a systematic database of properties and effects suitable for human application. Graphical abstract

Bacteria are widely distributed in the natural environment and the surfaces of objects, bringing about much trouble in our lives. Varies nanomaterials have been demonstrated good effect on killing microbe, but the consistency and stability seem to be improved. Recently, antibacterial effect on surfaces of some natural nanostructures was recognized, and more and more evidences were provided as a new type of bactericidal mechanism, the physical sterilization. The dragonfly and cicada wings have been found to possess the most exceptional antibacterial properties because of the specific nanostructure. Inspired by the biofunctions, researchers began to build a series of physico-antimicrobial surfaces on different materials to avoid the abuse of antibiotics and the environmental pollution of organic antibacterial agents. The physico-antimicrobial structure does not rely on chemical components, and a series of physico-antimicrobial models have been established. To deeply understand the physically bactericidal effect, this article reviews a series of natural and biomimetic physical antibacterial surfaces and makes reasonable expectations for the application of such composite materials in constructing physical antibacterial surfaces.

Fused deposition modeling (FDM) uses computer-aided design to direct a 3D printer to build successful layers of product from polymeric materials to generate 3D devices. Many reviews have been reported recently on the cutting-edge FDM technology from different perspectives. However, few studies have delved into the advances in FDM technology from materials to 3D devices. Therefore, in this work, with a bottom-up approach from materials (including commodities and nanomaterials) to printing process (including effort for fast printing, effort for resolution improvement, and simulations) and from printing process to 3D devices (including biomedical implants, topological structures, and multifunctional devices), it aims at reviewing the FDM technology developed over the past decades.

As the most common energy storage technology on the market, lithium-ion batteries are widely used in various industries and have a profound impact on our daily lives, with the characteristics of high voltage, high capacity, good safety performance, and long cycle life. Lithium metal was first used in the anode of lithium-ion batteries. However, the inherent growth of lithium dendrites and the instability of the SEI film limit the practical application of lithium metal materials. Despite this, lithium metal is still an ideal anode material to meet the growing demands for electronic equipment and electric vehicles due to its extremely high theoretical specific capacity, low density, and the lowest negative electrochemical potential. With the urgent need to develop new energy storage technologies, the research on lithium metal anodes has once again received extensive attention. In this review, the research progress in the modification of composite lithium metal electrode materials is summarized, including lithium/alloy composite electrode, lithium/carbon-based materials composite electrode and artificial SEI film. The possible directions for future development of lithium metal electrode are also prospected.

Applications of carbon fiber reinforced epoxy-based composites have been highly restricted due to their high cost in the manufacturing process. Cellulose, a cheap and abundant material from nature, shows excellent mechanical property and structural stability. It shows huge potentials in substituting carbon fiber/epoxy with cellulose/epoxy composites to fulfill the great demands for composites with good performance and a reasonable price. This paper first reviews works about the preparation and regulation of cellulose materials based on the very basic concepts of top-down and bottom-up. Then research about the interfacial regulation between cellulose and epoxy has been discussed in two broad classes of covalent and non-covalent modification. Finally, the enhancement effect of cellulose reinforcement has been discussed in two broad classes of dispersive reinforcement and continuous phase reinforcement. The latter can be further divided into three classes according to the dimension feature (1D, 2D, and 3D). The results show that the nanolization of cellulose is necessary for guaranteeing the strength of composites, while the formation of macroscopic and continuous structures can ensure Young’s modulus of composites.