Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
Changes in shear elastic constant, long-range order, and lattice parameter were measured during disordering and eventual amorphization of ${\mathrm{Zr}}_{3}$Al by ion irradiation. Large (\ensuremath{\simeq}50%) elastic softening was observed during disordering, and anomalies occurred in all three measured parameters o…
An Introduction to Polyurethanes Making Polyurethanes The Chemistry and Materials of Polyurethane Manufacture Low Density Flexible Foams High Density Flexible Foams Reaction Injection Moulding Rigid Polyurethane Foams Polyurethane Elastomers Polyurethane Adhesives, Binders, Paints, Lacquers, Cellular Coatings and Othe…
We report measurements of the solid-solid thermal boundary resistance Rbd, spanning the temperature range from 1 to 300 K. Below 30 K, Rbd is found to be in agreement with the prediction of the acoustic mismatch model. The influence of diffuse scattering at the interface is found to have a very minor influence on Rbd.…
Abstract The preparation of strongly luminescing sols of Q‐CdS (Q indicates size quantization effect) and of co‐colloids of CdS and ZnS.
We report the first experimental evidence for the existence of free polyexcitons ($n>2$) in a semiconductor. Resolved polyexciton lines, together with the biexciton line, were observed in the green photo-luminescence spectrum of ultrahigh-purity silicon. We propose that the unresolved luminescence of these polyexci…
A quasiperiodic pattern (or quasicrystal) is constructed in real four-dimensional Euclidean space, having the non-crystallographic reflection group (3, 3, 5) of order 14 400 as its point group. It is obtained as a projection of the eight-dimensional lattice E 8 , and has as a cross section a three-dimensional quasicry…
High-resolution electron microscopy shows the coexistence of several distinct core structures for coincident-site lattice boundaries in NiO bicrystals near $\ensuremath{\Sigma}=5, (310)$, and $\ensuremath{\Sigma}=13, (510)$, where $\ensuremath{\Sigma}$ is the reciprocal density of coincident lattice sites. Lattice exp…
The authors consider the relationship between Newman's superposition-model formulae and the recently derived transformation matrices S k ( phi , theta ) for the extended Stevens operators. The coordination factors K k q ( theta , phi ) are shown to be the matrix elements (S k -1 ) 0q . A general expression for K k q i…
The use of solution mixing followed by gelation to make ultrahomogeneous glasses and ceramics of various oxide compositions for laboratory experimentation, with first organic and later principally colloidal inorganic, precursors was developed over 30 years ago. Major technologies that use the solution-sol-gel route ha…
Dipole-relaxation parameters for ${\mathrm{Ce}}^{3+}$-${\mathrm{F}}_{\mathrm{int}{}^{\mathrm{\ensuremath{-}}}}$ centers (${C}_{4v}$ symmetry) in ${\mathrm{CaF}}_{2}$ are calculated using the method of ionic thermocurrents (ITC). The data indicate concentration-dependent effects if analyzed using the traditional ITC eq…
The Raman spectrum of ammonia solid I in the lattice and intramolecular regions has been studied at temperatures between 93.6 and 213.5 K. The three most intense lines in the lattice region, one librational and two translational modes, have frequencies and linewidths whose temperature dependence can be explained by an…
Raman scattering from acoustic phonons in a GaAs/${\mathrm{Ga}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{Al}}_{\mathrm{x}}$As Fibonacci superlattice is reported. Peaks are observed at a set of frequencies that are found to be in good agreement with theoretical predictions based on an elastic continuum model. The…
The distinct variation of the surface enhanced Raman spectral pattern of piperidine under different applied voltages is analyzed with the Wolkenstein’s approximation to reveal its very molecular implication. The calculated effective polarizability derivatives show that there are both chemical and electromagnetic mecha…
An ion-assisted evaporation process is described for the formation of ITO films on substrates that cannot be heated beyond 150 degrees C. Refractive indices and absorption coefficients were measured in the visible part of the spectrum for some of the films. The resistivity of the films varied between 0.7 and 8 x 10(-3…
Site-selective laser spectroscopy has been used to investigate the defect structure of a 0.1 mol % ${\mathrm{Pr}}^{3+}$:${\mathrm{CaF}}_{2}$ crystal. Twenty-three distinct sites have been identified from the fluorescence spectra. Only three of the sites were found to be single-ion sites while the rest were assigned to…
Static electronic hyperpolarizabilities of alkali halide crystals are computed in a local-density-approximation scheme. It is found that the anion nonlinear susceptibilities are extremely sensitive to the crystalline environment while the cation values are not. Calculations using pseudopotentials to represent overlapp…
Structures and optical-absorption edges of ${\mathrm{As}}_{2}$${\mathrm{S}}_{3}$ glasses prepared by quenching at various temperatures have been studied. Raman scattering spectra show that the medium-range order decreases in the specimens rapidly quenched from temperatures higher than the glass-transition temperature,…
Stable microbubbles are a ubiquitous feature of natural waters, acting as sites for mechanical and acoustical cavitation and nucleii for bubble growth at low gas super‐saturations. Stable microbubble populations that have been determined acoustically in the past are not well explained by existing models of bubble stab…
An exact field theory is presented to describe a system of self-avoiding lattice polymer chains with arbitrary regularly branched architecture. Equivalently, the chains can be viewed as linear and as composed of structural units (monomers) having a chosen shape and size and therefore each occupying more than one latti…
Further insight into the structure and dynamics of amorphous water ice, at low temperatures, was obtained by trapping in it Ar, Ne, H2, and D2. Ballistic water-vapor deposition results in the growth of smooth, approximately 1 x 0.2 micrometer2, ice needles. The amorphous ice seems to exist in at least two separate for…