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。
The elastic constants K11, K22, and K33 of some members of two homologous series of nematic liquid crystals, the p,p′-di-n-alkyl and p,p′-di-n-alkoxy azoxybenzenes, are reported. Both K11 and K33 become greater with increasing alkyl chain length, while the ratio K33/K11 decreases along the series. For small alkyl chai…
The effects of compositional, vibrational, long-range positional, and topographical disorders upon the angle-resolved photoemission spectra of tightly bound valence electrons are investigated. In order to take into account the strong potential sensed by the electron in the vicinity of the atomic core, an augmented-pla…
Raman and far-infrared reflectivity spectra have been obtained for both stoichiometric and nonstoichiometric Ti${\mathrm{Se}}_{2}$ above and below the transition temperatures corresponding to formation of the $2{a}_{0}\ifmmode\times\else\texttimes\fi{}2{c}_{0}$ superlattice. In the normal phase above ${T}_{c}$ Raman-a…
A first-principles energy-band study of the metallic rutile phase of V${\mathrm{O}}_{2}$ using a general crystal potential and an expansion of the Bloch functions in a linear combination of atomic orbitals is reported. The results are compared with previous work and experimental optical, x-ray absorption and emission,…
The transport properties of the linear-chain metal Nb${\mathrm{Se}}_{3}$ are anomalous. Giant increases in the dc resistivity appear at 145 and 59 K, suggestive of charge-density-wave (CDW) formation. These anomalies show breakdown effects with applied electric fields as low as 0.1 V ${\mathrm{cm}}^{\ensuremath{-}1}$.…
The polarized reflectance at room temperature of potassium-tetracyanoquinodimethane (K-TCNQ) has been measured. Analysis using the Kramers-Kronig transforms gives the response functions (dielectric function and conductivity) between 300 and 23 000 ${\mathrm{cm}}^{\ensuremath{-}1}$. Attempts have been made to fit these…
The resonance of the Raman scattering by ${E}_{2}, {A}_{1T}, {E}_{1L}$, and ${E}_{1T}$ phonons, and several second-order features, has been studied for ZnO for photon energies between 1.6 and 3 eV. The results are interpreted with a dielectric theory based on the first and second derivatives of the dielectric constant…
Hair samples from 31 learning disabled and 22 normal children were analyzed for content of 14 elements. Significant group differences were determined and a discriminant function was completed which separated the groups with 98 per cent accuracy. Elevated lead and cadmium content in the learning disabled group is viewe…
The relevance of a high-temperature mechanism for vacancy migration, the double jump, has been established by molecular dynamics in Al and Na. Migration energies for single jumps are 0.42 \ifmmode\pm\else\textpm\fi{} 0.1 eV and 0.12 \ifmmode\pm\else\textpm\fi{} 0.02 eV, respectively, while for double jumps they are ab…
Thin-film lenses, mirrors, and diffraction gratings have been fabricated from electon-beam-generated masks. These masks were used to make iron oxide working masks for photolithographic fabrication of these passive components in Nb2O5 optical waveguides. The optical-waveguide characteristics of these components are dis…
Unusual band images observed by dynamical diffraction X-ray topography in nickel single crystals are elucidated by a model of very thin magnetic domains which extend obliquely through the thickness of the crystal. These thin domains have a magnetization direction which would cause free-pole formation on the crystal su…
New bands assigned to scandium hydride have been observed in emission in the green (5580 Å) and near infrared (8603 Å) regions. The identity of the carrier as ScH is established on the basis of the observed deuteride spectrum.
Polarized absorption spectra of centrosymmetric neodymium hexakis-antipyrine tri-iodide single crystals at 77 and 20\ifmmode^\circ\else\textdegree\fi{}K have been discussed. The spectrum is complicated by the appearance of a large number of vibronic lines. A phase transition destroying the inversion symmetry occurs be…
Abstract and Summary Lactitol was oxyalkylated with propylene or ethylene oxide. The resulting ether‐alcohols were transesterified with a series of fatty acid esters in order to produce long chain ether‐esters of lactitol. These compounds were found to be more water soluble than related lactitol derivatives prepared b…
The threshold fields of laser-induced breakdown in dielectric liquids (dimethyl silicon oil and linear hydrocarbon liquids) were experimentally studied as the functions of increasing molecular weight and decreasing temperature and found to decrease. By comparison, slightly increase. From these results, laser-induced b…
Longitudinal and transverse magnetostrictions along the a , b and c axes of SmFeO 3 and YFe 1- x Co x /2 Ti x /2 O 3 (0.004≦ x ≦0.012) were measured. In both of the orthoferrites, the magnetostriction increases in magnitude near the spin reorientation temperature region, reaching maximum value of Δ l / l ∼15×10 -6 und…
An apparatus is described for the investigation of chemically stimulated, photostimulated and tribostimulated exoelectron emission. Emphasis was placed on tribostimulated emission from uniaxially deformed oxide-covered metals (aluminium, titanium and nickel). Experiments were performed in either ultra-high vacuum or a…
Major types of defects appearing in calendered films and sheets are described. The conditions for the appearance of air bubbles and mattness were studied for the particular case of calendering crystal-clear, rigid, toughened PVC. A correlation was found between the presence of air bubbles in the film and a distributio…
A climb model of extended dislocations based on jog pair nucleation is proposed. The energy of an extended jog pair is computed for different stacking fault energies. The results show a critical jog size from which the extended jog pair may develop by glide. This critical size is related to the stacking fault energy.…
Using a power-law viscosity, then connecting power-law fluid and thermo-dependence of the viscosity, we compute the applied stresses between the rollers during calendering (pressure curve-maximum pressure and shear stress-roll separating force and the applied opposing torque) as well as the temperature evolution of th…