Materials Literature
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An overview of polymer dispersed liquid crystal (PDLC) materials, their physical properties, and potential applications in the optic and electrooptic industry is presented. These optoelectronic materials have unique properties which are expected to expand liquid crystal technology into new display and light shutter ap…
Eight mutants of Alcaligenes eutrophus defective in the intracellular accumulation of poly-beta-hydroxybutyric acid (PHB) were isolated after transposon Tn5 mutagenesis with the suicide vector pSUP5011. EcoRI fragments which harbor Tn5-mob were isolated from pHC79 cosmid gene banks. One of them, PPT1, was used as a pr…
The toughening behavior of whisker‐reinforced ceramics is analyzed in terms of a whisker bridging zone immediately behind the crack tip. This approach is consistent with microscopy observations which reveal that intact bridging whiskers exist behind the crack tip as a result of debonding of the whisker‐matrix interfac…
Pseudomonas oleovorans grows on C(6) to C(12)n-alkanes and 1-alkenes. These substrates are oxidized to the corresponding fatty acids, which are oxidized further via the beta-oxidation pathway, yielding shorter fatty acids which have lost one or more C(2) units. P. oleovorans normally utilizes beta-oxidation pathway in…
Abstract The relationships between the composition and the crystallization temperature of chlorites and illites have been investigated in different geothermal fields and in particular the Los Azufres system in Mexico, considered to be a natural analogue to experimental laboratories, as the main changes in physical and…
A Fortran program has been developed for the reduction of single-crystal diffraction data from a sequence of adjacent rotation pictures recorded at a fixed X-ray wavelength by an electronic area detector. The electronic pictures (data frames) covering the first 5° of crystal rotation are used to locate strong diffract…
The electronic structure of copper oxides has been investigated by photoelectron (x-ray photoemission, ultraviolet photoemission), Auger electron, and bremsstrahlung isochromat spectroscopies. The experimental results are compared with one-electron band-structure calculations as well as with a cluster configuration in…
We have developed a new technique, based on the standard Monte Carlo simulation method with Markov chain sampling, in which a set of three dimensional particle configurations are generated that are consistent with the experimentally measured structure factor. A(Q), and radial distribution function, g(r), of a liquid o…
The authors investigate the thermodynamics of a lattice gas model for intercalation, employing a nearest-neighbour intra-plane attraction and both attractive and repulsive forces which decrease with increasing distance between the planes. The free energy F is calculated within the mean-field approximation. The phase d…
The magnetic structures of the orthorhombic rear-earth manganates ErMn 2 O 5 and TbMn 2 O 5 have been studied by single-crystal neutron diffraction at temperatures between 1.5 and 25 K. Both materials exhibit amplitude-modulated magnetic structures with propagation vector (0.5, 0, 0.247) (Er) or (0.5, 0, 0.308) (Tb) a…
The current status of the physics of liquid-crystalline polymers is reviewed. Major attention is paid to the theory of the nematic state of solutions and melts of polymers of varying architecture, and also of polyelectrolytes. The conditions for phase equilibrium in solutions and melts and the elastic properties of sy…
Forced Rayleigh scattering is used to measure the self-diffusion of charged polyball suspensions driven far from equilibrium by an oscillating shear flow. Aside from the usual enhancement of the diffusion due to Taylor dispersion, we observe an additional isotropic contribution which increases linearly with the shear…
Studies by small-angle neutron scattering have been conducted on a main-chain thermotropic nematic polymer composed of alternating mesogens and flexible spacers. The anisotropy of chain conformation in the nematic phase was measured in the melt and in a dilute nematic solution. The variation as a function of degree of…
We compare for the first time gas-phase $3s$ and $3p$ spectra from atomic Mn with corresponding spectra from the solid compounds Mn${\mathrm{F}}_{2}$ and MnO. These spectra are found to be strikingly similar, indicating that the solid-state spectra have a dominant origin in unscreened intra-atomic multiplet splittings…
The phase diagram for liquid-crystal models of hard molecules is studied by use of a nonlocal density functional for the free energy. Nematic, smectic-$A$, and smectic-$C$ phases can be obtained from purely packing effects without any attractive interaction. A system of parallel hard spherocylinders shows a continuous…
In a directional solidification experiment on a moving nematic-isotropic interface, we observe solitary modes propagating across the interface. We also observe the Eckhaus instability. In the presence of solitary modes, the pattern-selection mechanism is dynamic.
Optical field induced first-order electric Freedericksz transition and electric bistability in a homogeneously aligned nematic film is first observed. It is experimentally demonstrated that an applied optical field can transform the electric Freedericksz transition from second order to first order. The molecular reori…
Photoemission spectra from potassium adsorbed on an Al{111} surface show a K $4s$-derived state just below the Fermi level, ${E}_{F}$, which is first observed just prior to the onset of ordering in the overlayer. The feature disperses upwards with increasing ${\mathbf{k}}_{\ensuremath{\parallel}}$ and crosses ${E}_{F}…
Loading a cantilevered bar allows studying the effect of a uniform, externally applied, and continuously variable strain field on the properties of surfaces. Straining a nominally flat Si(100) surface produces unequal populations of the 2 \ifmmode\times\else\texttimes\fi{} 1 and 1 \ifmmode\times\else\texttimes\fi{} 2…
A density-functional theory, based on the smoothed density approximation, is presented in order to study phase transitions in systems of hard spherocylinders with full translational and orientational degrees of freedom. We find both the nematic-isotropic and the $\mathrm{n}\mathrm{e}\mathrm{m}\mathrm{a}\mathrm{t}\math…