Volume 48, Issue 12

Starting from the ideal magnetohydrodynamic (MHD) equations, we consider the following axisymmetric configuration: a current-carrying plasma torus in a homogeneous magnetic field that is aligned parallel to the torus axis. At a certain field strength this configuration is in equilibrium without need of external current singularities such as wires or walls.The magnetic flux function is expanded in small inverse aspect ratio. The geometry of this configuration is completely determined to second order as a function of the profile parameters.

The gravitational force is assumed to be mediated by spin 2 gravitons which are composed of four spin 1/2 (sub-) fermions. The dynamics is governed by a nonlinear spinorfield equation with nonperturbative Pauli-Villars regularization and canonical quantization. On the quantum level the fermion dynamics is expressed by a functional equation for algebraic state functionals, and the "graviton" (functional) states are defined to be solutions of the diagonal part of this equation. The effective interaction between such graviton states and fermions is studied by means of a weak mapping between the original functional equation and an effective functional equation for gravitons and fermions. In the low energy limit this mapping produces for the effective fermion dynamics (apart from selfinteractions) a Dirac equation in anholonomic coordinates coupled to the anholonomic connections of a gravitational field, i.e. the usual phenomenological expression for a gravitational force acting on spin 1 /2 fermions.

We study in detail the evolution of fractal structure within a two dimensional hyperbolic baker's map with a complete set of unstable orbits. The evolution of fractal structure within the phase space of the map is related to changes in an associated Cantor set, and this evolution is studied via their corresponding /(a) spectra. Numerical calculations of unstable periodic orbits for a related baker's map, with an incomplete set of unstable orbits, is investigated and directly related to, and characterized by, a pruned Cantor set. The effect of the pruning on the associated /(a) spectrum of the baker's map is analyzed.

The effect of 2-phenylindole (2PI) concentration in p-xylene upon the fluorescence decay time was investigated by frequency-domain fluorometry. The fluorescence decay of a dilute (10~ 5 M) 2PI solution in p-xylene at 20 °C is single exponential with the mean decay time t = 1.87 ns and practically independent of the observation wavelength (A obs) in the fluorescence band. The fluores-cence decay in a highly concentrated solution (6 x 10" 3 M) is heterogenic and depends on A obs . For a given modulation frequency (~ 200 Hz), the fluorescence phase shifts at the longwave observation (440-480 nm) distinctly exceed 90°, thus clearly indicating that the observed (excimer) fluorescence results from a process taking place in the excited state. The fluorescence decays were measured at seven values of A obs (360-480 nm), and all the results were analyzed comprehensively (tj and t 2 are equal for all A obs ; the amplitudes are different). The lifetimes of the excimer state is relatively short (~3.5 ns). Radiative (r e) and non-radiative (t,) rate constants for monomer fluorescence of 2PI in p-xylene were determined using appropriate data from photo-and radioluminescence measure-ments.

Photoisomerization of 1,4-diphenyl-1,3-butadiene (DPB), 1,6-diphenyl-1,3,5-hexatriene (DPH) and 1,8-diphenyl-1,3,5,7-octatetraene (DPO) in poly(vinyl alcohol) (PVA) films was studied unter daylight and direct irradiation. The most efficient photoisomerization occurs in the DPB molecule, the smallest among the compounds investigated. For the greatest, DPO, molecule no distinct isomerization was observed in daylight and only a temperature effect was noted. Therefore, the DPO molecule in the PVA film heated to 423 K may serve as a fluorescence standard.

We apply the Unsymmetrized Self-Consistent-Field-Method (USCFM) to a linear infinite chain of identical atoms with a quartic pair interaction potential. We show that an exact solution of the USCFM can be found in terms of a single auxiliary function ℒ 1 which is studied here in details. We use it to calculate the partition function, the energy and the free energy, the moments of the position, the corrections due to quantum effects and higher terms of the potential, the specific heat and the thermal expansion. An anharmonic approximative approach, based on the self-consistent potential of the used method, is developed also. We apply these two approaches to the study of the thermoelastic properties of a one dimensional system (krypton). It is demonstrated that the approximate approach is very effective when dealing with pairwise potentials of positive second derivative. The Lennard-Jones potential is used in our calculations.

Åbstract The spectra of the out-of-plane fundamental band of furane (C 4 H 4 O) centered at 744 cm -1 and of thiophene (C 4 H 4 S) at 712 cm -1 were measured in Doppler-limited resolution with a diode-laser spectrometer at Köln and with a high-resolution Fourier transform spectrometer at the University of Gießen. An interactive Loomis-Wood program was applied to identify the c-type transitions of furane and thiophene. The molecular parameters were determined from the observed line positions and the available microwave data by least-squares-fits using Watson's A-reduced Hamiltonian. Some relations among parameters appearing in different formulations of the Hamiltonian are represented explicitly in connection with the derivation of the unreduced constants. The unreduced constants were derived for both molecules using the planarity relations. We determined the inertial defects to be ≈ 0.05 amuÅ 2 in the ground state and ≈ -0.2 amuÅ 2 in the excited state for both furane and thiophene.

Using a neutron double crystal spectrometer, thin amorphous Ni-Pd-P-samples were investi-gated at very small Q-values (10 -5 Å -1 ≦Q≦10 -3 Å -1 ). The immersion method shows that the small angle scattering effect is mainly caused by surface scattering.

Internal mobility ratios in the molten binary systems (Ag,Rb)NO 3 and (Ag,Cs)NO 3 have been measured by Klemm's countercurrent electromigration method at various temperatures and compositions. From these and the available data on the densities and conductivities, the cation internal mobilities b have been calculated. Over the investigated regions of temperature and composition b Ag is greater than b Rb and b Cs . The internal mobility of Ag + is well expressed by b Ag = [A/(V - V 0 )] • exp(-E/RT), where V is the molar volume of the mixtures, A, V 0 , and E being constants nearly independent of the coions. A comparison of the present data with those previously obtained by the EMF method certifies that the Klemm method yields more precise data.

The homogeneity range of Bi-Sr-Ca-Cu oxides with two-layers ("2212") structure has been investigated with X-ray powder diffraction and electron microprobe determination on materials with nominal Bi 2 Sr 3-x Ca x Cu 2 O 8+y ) , (x = 1÷ 2 in 0.1 steps) composition and being prepared at two different oxygen partial pressures. The results show Bi over-stoichiometry and a wide range of Sr/Ca substitution. DC resistivity measurements indicate that the hole concentration is controlled by both oxygen non-stoichiometry and cation molecularity. It is shown that a single phenomenological relation between hole concentration and electrical properties can explain in a consistent way the complex behaviour of the whole set of materials with different oxygen non-stoichiometry and cation molecularity.

We investigated the 33 S nuclear quadrupole coupling of thiazole- 33 S in natural abundance by molecular beam Fourier transform microwave spectroscopy. In addition the 14 N nuclear quadrupole coupling could be analyzed with high precision. We derived the rotational constants A = 8529.29268 (70) MHz, B = 5427.47098 MHz, and C = 3315.21676 (26) MHz, quartic centrifugal distortion constants and the quadrupole coupling constants of 33 S χ aa = 7.1708 (61) MHz and χ bb = -26.1749 (69) MHz and of 14 N χ aa = -2.7411 (61) MHz and χ bb = 0.0767 (69) MHz.

Internal mobility ratios of the two cations in the molten binary systems (Li, Na)Cl and (Na, K)Cl have been measured with Klemm's column method. From these and available data on the densities and conductivities the internal mobilities b Li , b Na and b K have been calculated. In (Li, Na)Cl, b Li is smaller than b Na in the investigated composition and temperature range, and in (Na, K)Cl, the Chemla effect occurs, that is a crossing of the isotherms is observed. The internal cation mobilities b M are well expressed by the empirical relation b M = [A/(V-V 0 )]exp(-E/RT), where A, E and V 0 are constants depending on the cation M and V is the molar volume of the mixture.

The set of relaxation times describing the dynamic dielectric properties of liquid polyethyleneglycol 200 at 20 and 40 °C is found to be practically independent of the admixture of polyvinylpyrrolidone, though the viscosity is appreciably increased. This is compared to the rather similar behaviour of small molecular solvents.

The dielectric spectrum of the title substance ('neohexanol') in its pure liquid state is reported for 293 K up to 71 GHz and, for a restricted frequency range, also for lower temperatures (down to 253 K). The room temperature spectrum resembles that of alicyclic alcohols, in particular cyclopentanol, with respect to spectral shape, main relaxation time and the relation of the latter to viscosity, which similarity may be connected with the fact that these alcohols are able to form 'plastic crystals'.

Using the discharge flow method, the kinetics of the gas phase reaction HOCO + O 2 products (1) was investigated at room temperature and pressures around p ≈ 2.0 mbar with Far Infrared Laser Magnetic Resonance (FIR-LMR) detection of HOCO, HO 2 , and OH. From the measured concentration- versus-time decay profiles of HOCO in the absence and presence of a large excess of O 2 , the overall rate constant of the reaction was found to be k 1 (296 K) = (9.9 ±1.5) • 10 11 cm 3 /mol • s. The main reaction channel, which leads to production of HO 2 + CO 2 , could be established.

With potential parameters adjusted to reproduce the experimental structure factor of molten MgCl 2 reasonably, molecular dynamics simulations of the molten NaCl-MgCl 2 were carried out. The structure of this system was investigated by comparison of experimental with computational results.

The theory of the magnetic circular dichroism (MCD) of cyclic re-electron systems with 4 N ± 1 electrons, such as the radical anion of [16] annulene, has been investigated in the perimeter model approximation. General solutions and formulas for the calculation of the Faraday parameters A, B, and C are derived analytically. The calculated and measured spectra of the 17 π-electron [16] annulene radical are in good agreement.

Experiments on threshold photoionization of benzene are performed which show very long lived neutral molecular states above the ionization threshold. These states are shown to have lifetimes of tens of microseconds and longer in the energy range of vibrational excitation of the molecular core as well as for electronic excitation in the range of 5 eV above the ionization potential (IP).

From the perspective of orthodox quantum theory, no meaning can be assigned to the notion of the "slit" through which the atom passed in the experiments under discussion in this paper. From a Bohmian perspective this notion does have meaning. Moreover, when we compare the answer provided by BM with the answer provided, not by orthodox quantum theory, but by a naive, largely incoherent operationalism, we obtain different answers. So what?

An indirect spectrofluorometric probe method is developed for calculating equilibrium constants for formation of heterogeneous solvent-solvent molecular complexes from measured fluorescence emission intensities in select systems that exhibit parabolic-shaped Stern-Volmer quenching plots.

Colour and fluorescence of lapis lazuli depend on its mineral components. UV-VIS-and fluorescence-spectra of specimen rich in lazurite differ from those rich in haüyne.