Materials Literature
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Closed nonlinear equations are derived for a self-consistent treatment of density propagation, self-diffusion and current relaxation in a classical monatomic fluid. The solution for a hard-sphere model system brings out a phase transition to a glass at the packing fraction 0.516. Approaching the transition from the gl…
The first observation of the nematic-smectic-$A$-smectic-$C$ multicritical point in a single-component liquid-crystal system is reported. High-resolution pressure-temperature data are presented, which support the view that the phase diagram is universal near the nematic-smectic-$A$-smectic-$C$ point.
We report high-precision measurements of the shear modulus, viscosity, and specific heat of cholesteryl nonanoate through its blue phases (BPI-BPIII). For BPI and BPII we find a shear modulus which remains finite as the frequency approaches zero, indicating that they are viscoelastic solids. We find that the cholester…
We show that the dynamically selected velocity and tip radius of dendrites in the boundary-layer model of solidification have the special values which permit the existence of steady-state needle-crystal solutions. This result, in conjunction with considerations of stability, provides new insight concerning the validit…
Plastic deformation and stability are investigated of the hardened and structural states of zinc single crystals with forest dislocations in the system {1122} 〈1123〉 by shearing in the slip system (0001) [2110]. It is found that at 293 and 77 K plastic deformation in such single crystals has a pronounced jump-like nat…
On the basis of the dynamical theory a new geometry of X-ray diffraction is suggested and analyzed in detail. Diffraction scattering occurs from the planes deviated by several degrees from the surface normal, the incident and diffracted beams forming small glancing angles with the surface. It is shown that the asymmet…
Structure peculiarities and disorderness of trigonal Ca3Ga2Ge4O14 and Sr3Ga2Ge4O14 crystals are considered. Absorption and luminescence characteristics and stimulated emission parameters of Nd3+ ions in said compounds are investigated. The luminescence intensity parameters of the activator are analyzed and the cross-s…
The transport equation is solved for a quantum-mechanical system in a transverse magnetic field. The solution gives the linear transport coefficients for electrostatic fields and temperature gradients for electrons in metals. In term of a small expansion parameter, the solution to lowest order confirms the existing se…
A linear, nonlocal continuum theory of dislocations is developed. The field equations are given for the dislocation density and the stress field due to continuous distribution of dislocations. Green’s functions are obtained for two- and three-dimensional media and an integral formula is given for line distribution of…
The Peltier heat of a charge carrier in a semiconductor is calculated for the situation in which the electronic energy levels are temperature dependent. The temperature dependences of the electronic energy levels, generally observed optically, arise from their dependences on the vibrational energy of the lattice (e.g.…
The copper salt of the amino acid α-amino isobutyric acid was synthesized and the crystal structure was determined by x-ray techniques. The crystals are monoclinic, space group P21/c (Z=2) with a=10.470(3) Å, b=5.335(1) Å, c=10.201(3) Å, and β=115.6(2)°. The magnetic susceptibility, measured between 1.4 and 12 K, show…
We investigated the diffusion of ion-implanted As in SiO2 with Rutherford backscattering spectrometry. By applying different annealing ambients and also encapsulating with a Si3N4 layer, we were able to distinguish three types of diffusion for implanted As in SiO2. These are correlated to two chemical states of As in…
The various electronic excitation channels which contribute to the production of photoelectrons and Auger electrons following x-ray absorption in a solid are discussed. In particular, we outline the contributions of elastic and inelastic photoelectrons and Auger electrons for the different electron-yield detection mod…
We derive a mathematical expression for the energy-loss spectrum or the energy distribution of electrons backscattered from a disordered film deposited on a substrate in terms of a primary scattering probability function corresponding to the elastic and inelastic scattering probabilities. Both single- and multiple-col…
We study linear polymer solutions containing different chemical species within the framework of the direct renormalization method introduced by des Cloizeaux. We study the osmotic pressure and polymer radii of dilute solutions containing two chemically different polymers A and B both in good and θ solvent when the int…
High‐velocity (∼2 to ∼5 km/sec) impacts into octahedrite iron meteorites (Gibeon, El Sampal, and Arispe), steel, and iron targets were made at the NASA‐Ames Vertical Gun Facility. The experiments clearly revealed the brittle behavior of meteorites at very low temperatures (<200° K) as indicated by spallation of the…
Polarized extended X-ray absorption fine structure (EXAFS) and near-edge spectra are measured on the Br K-edge for streteh-oriented trans -(CHBr y ) x . A large difference is observed in both the EXAFS and near-edge regions between the spectra with the polarization vector E parallel and perpendicular to the axis of or…
In compensated semiconductors, the occurrence of potential fluctuations which affect the local probability of ionization of deep levels cannot be ignored. These fluctuations strongly change the frequency and temperature dependence of the conductivity due to carriers in the bands. The expressions of ac and dc conductiv…
Metallic thermopower data on ${\mathrm{FeCl}}_{3}$-doped polyacetylene are presented. We compare the results with the data on iodine- and ${\mathrm{AsF}}_{5}$-doped polyacetylene in the heavily doped regime. General features of the results are consistent with those of a simple metal. However, details are different. We…
It is shown that a layer of liquid crystal molecules adsorbed on an evaporated SiO film plays an important role in aligning the bulk of the liquid crystal, apart from the topographical structure of the SiO film. On an SiO film evaporated from the substrate normal, various textural patterns were observed depending on h…