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。
Dislocation behaviour as a function of applied stress has been studied in the stressed state in a zone-refined aluminium single crystal at room themperature using the Lang X-ray topography technique. The ends of moving primary dislocations make an angle to the surface according to the angle found by solving Lothe's en…
The observation of faint fringe patterns between 1/2 〈110〉 dislocations in electron micrographs of a lightly deformed Cu-15.6 at% Al alloy is attributed to the destruction of short-range order giving AlAl nearest neighbours across the slip plane with consequent expansive dilation. The expansive dilation is estimated…
Using a localized-electron model it is shown that the spontaneous and foreced volume magnetostriction, ωm and ∂ωm/∂H can be consistently interpreted assuming a volume dependence of the exchange interaction. This is expressed by J′1, the first derivative of the exchange intergal I1(r) with respect to the interatomic di…
The photoluminescence of Se single crystals was investigated at 4 K under the influence of ac and dc electric fields. From the results followed a classification of the seven lines into two groups with different behaviour. The luminescence of one group is quenched in an electric field while that of the other group is a…
The magnetic circular dichroism (MCD) of the aqueous solution of potassium trismalonatoferrate (III) is measured at room temperature over the region 400–750 nm. The MCD of the spin-forbidden d-d transitions of high-spin iron (III) complexes is analyzed on the basis of ligand field theory. The electric dipole transitio…
The primary oxidation and reduction products produced by ionizing radiation in single crystals of barbituric acid irradiated at 4.2 °K have been identified from their ESR and ENDOR spectra. The primary reduction product is an anion formed by electron addition. The primary oxidation product is a neutral radical resulti…
The usual phonon Boltzmann equation is solved by using two mean relaxation times, ${\ensuremath{\tau}}_{N}$ for normal and ${\ensuremath{\tau}}_{R}$ for resistive processes. For a Debye solid with three polarizations, an explicit expression for the Fourier transform of the local temperature in a heat-pulse experiment…
Vibronic wavefunctions for trimers are used to calculate the A and B parameters characteristic of MCD spectra. In the weak-coupling limit both the A and the B parameters are zero for s = 0 states and nonzero for s = ±1 states. In the strong-coupling limit, the vibrationally induced 0–1 transition has nonzero A and B p…
The solution absorption spectrum of Es3+ has been measured in the region 10 000–34 000 cm−1. The observed band structure has been interpreted in terms of free-ion energy levels calculated using parameters that are consistent with those obtained in analyses of the specta of earlier members of the 5fN-series. The correl…
Crystals of DL-aspartic acid (C4NO4H7) were grown at room temperature from an aqueous solution of the commercially available sample. The crystals be- long to the monoclinic system with cell dimensions a= 18.947+0.002, b= 7.433 + 0.001, c=9.184 + 0.001 A and fl=123.75+0-02 °. The systematic absences are: hkl, h + k = 2…
Single crystals of silicon telluride, which has an unusual 2:3 stoichiometry, have been grown by a chemical vapor deposition technique. A photoluminescence level at 1.3 eV has been found as well as strong EPR signals, suggesting defects in the crystal which also could explain other unusual features. Thin films and bul…
α-VPO 5 crystallizes in the tetragonal space group P4/n with a = 6.014(7) and c = 4.434(2) Å. The structure, isotypic with that of α-VSO 5 , was refined by full-matrix least-squares method to an R value of 0.089 using 239 independent reflections. The vanadium ion lies on a crystallographic four-fold axis, as does one…
The Seebeck coefficient $\ensuremath{\alpha}$ for pure and V-doped ${\mathrm{Ti}}_{2}$${\mathrm{O}}_{3}$ single crystals has been measured between 54 and 500 K. A very strong peak in $\ensuremath{\alpha}$ near 75 K for ${\mathrm{Ti}}_{2}$${\mathrm{O}}_{3}$ is interpreted as arising from phonon-drag effects; this peak…
The electron spin resonance of the Gd3+ ion has been studied in two series of glasses having the molar compositions 6SiO2:5Na2O: x (Gd2O3 + Y2O3) with 0 ≤ x ≤ 0.5 and 500SiO2: x Na2O:1Gd2O3 with 2.5 ≤ x ≤ 494. The spectra were nearly independent of temperature and sample composition, but varied strongly with microwave…
The evolution with $x$ of the monoclinic-to-tetragonal transition temperature and of the room-temperature monoclinic structures of the system ${\mathrm{V}}_{1\ensuremath{-}x}{\mathrm{Cr}}_{x}{\mathrm{O}}_{2}$ have been reexamined and extended to cover the entire solid-solution range $0\ensuremath{\le}x<0.20$. The s…
We report the preparation of intercalation compounds of 2H–TaS2 with post transition period elements. In general we find that elements to the left of the metalloid line in the periodic table will intercalate TaS2. Crystallographic lattice parameters, the maximum amount intercalated per Ta, magnetic susceptibility, and…
A phenomenological dielectric approximation is proposed for studying the response of metal surfaces to external charge distributions and is illustrated by detailed calculations using the Thomas-Fermi model. The procedure is based on the replacement of the dielectric-response kernel in a constitutive relation by its as…
By using the techniques of wavelength-modulation spectroscopy, we have measured the reflectivity $R(\ensuremath{\omega})$ and the derivative of the reflectivity, $\frac{(\frac{1}{R})dR}{d\ensuremath{\omega}}$, for PbTe, PbSe, and PbS from 1.5 to 6 eV. We have independently calculated the band structure, frequency-depe…
We discuss the threshold conditions for the nucleation of a static Helfrich distortion of a planar cholesteric structure under a magnetic field or an ac electric field applied parallel to the helical axis. In opposition to the case of nematics, the magnetic threshold in cholesterics is definitely lower than the thresh…
We observe a second-order nematic to smectic-$A$ phase transition in $p$-nitrilebenzylidene-$p$-octyloxyaniline using the Rayleigh scattering technique. The twist elastic constant ${K}_{22}$ diverges at the transition, with the critical exponent $\ensuremath{\nu}=0.66\ifmmode\pm\else\textpm\fi{}0.05$ in agreement with…