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。
Time-resolved OH(X 2Πi,v=1–9) populations have been measured and analyzed to determine parameters relating to formation mechanisms and vibrational relaxation. OH(v) was formed in electron-irradiated Ar/H2/O3 mixtures containing added O2 or CO2 as relaxer species. OH(v→v−1,v−2) emission was observed using time-resolved…
The temperature dependence of dielectric dispersion in [N(C 2 H 5 ) 4 ] 2 ZnCl 4 single crystal, whose transition temperature is 220 K, was measured in the temperature range from about 200 K to 300 K. A notable dispersion is found only along the a -axis. The relaxation time, which increases as the transition temperatu…
The local geometric and electronic structure around a zirconium atom substituted for yttrium in ${\mathrm{Y}}_{2}$${\mathrm{O}}_{3}$ was investigated both experimentally and theoretically. X-ray-absorption measurements were performed at the Y and Zr K and ${\mathit{L}}_{\mathrm{II}}$ edges, in the extended x-ray-absor…
Minimal-basis tight-binding theory, using free-atom term values and nearest-neighbor universal 1/${\mathit{d}}^{2}$ coupling, and an A/${\mathit{d}}^{3}$+B/${\mathit{d}}^{12}$ repulsion, is used to calculate elastic properties without further approximations. Specifically, the shear constants (${\mathit{c}}_{11}$-${\ma…
A Fourier transform infrared study of the vibrational spectrum of Si2C produced by vaporizing mixtures of silicon and carbon-12 or carbon-13 and quenching the products in Ar at 13 K has confirmed a previously observed vibration at 1188.4 cm−1 as the ν″3(b2), antisymmetric Si–C stretching mode, and resulted in the iden…
Frequency-dependent conductivity measurements are reported in the charge-density-wave state of ${\mathrm{K}}_{0.3}$${\mathrm{MoO}}_{3}$ and ${\mathrm{K}}_{0.3}$${\mathrm{Mo}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{W}}_{\mathit{x}}$${\mathrm{O}}_{3}$ alloys in the radio-frequency, microwave, millimeter-wave, an…
The relationship between the anionic groups of \ensuremath{\beta}-barium borate and lithium borate nonlinear optical (NLO) crystals and their bonding, electronic structure, and transmission cutoffs has been studied using the discrete variational self-consistent multipolar X\ensuremath{\alpha} method [B. Delley and D.…
Theoretical calculations show that inhomogeneous doping can increase the efficiency of thermoelectric generators and refrigerators.
A combination of magnetic and electron microscopic measurements on iron deposited in chemically widened anodic aluminum oxide films has allowed us to relate the coercivity of these materials to the dimensions of the metal particles. The coercivity is found to be highly anisotropic and to depend on the aspect ratio of…
We provide a comprehensive analysis of the microstructure of the porous glass, vycor. Using transmission electron microscopy, small-angle x-ray scattering, molecular adsorption, and the dynamic process of direct energy transfer, a consistent picture of the mass, pore, and interfacial features of this material is prese…
We report the polarized absorption ${\mathrm{\ensuremath{\alpha}}}_{\mathrm{\ensuremath{\theta}}}$(\ensuremath{\Elzxh}\ensuremath{\omega}) and photoluminescence ${\mathit{L}}_{\mathrm{\ensuremath{\theta}}}$(\ensuremath{\Elzxh}\ensuremath{\omega}) spectra of gel-processed blends of poly(2-methoxy,5-(2'-ethyl-hexoxy)-p-…
We propose an approach to the calculation of the cohesive and the structural properties of solids. This approach is based on the second theorem of Hohenberg and Kohn and allows one to obtain directly the charge density and the total energy without determining, at the same time, the band structure of the system. The me…
The electronic structures, the charge-density distribution, and the total energies of boron nitrides (BN) in the hexagonal, cubic, and wurtzite structures are studied by first-principles self-consistent local-density calculations. For the ground-state properties, the band structures, the equilibrium lattice constants,…
We report on the first spin- and momentum-resolved photoemission studies on epitaxial f.c.c.-cobalt films above the Curie temperature. In order to obtain a thorough characterization of the electronic states, the photoelectrons have been excited by circularly polarized VUV synchrotron radiation and a vectorial spin ana…
The dielectric, pyroelectric and thermal properties of ferroelectric Bi 2 VO 5.5 (Bi 4 V 2 O 11 ) ceramic have been studied over a temperature range of 300-780 K. The sign of the pyroelectric coefficient is positive at room temperature. The dielectric constant, pyroelectric coefficient and specific heat exhibit anomal…
Self-trapping of holes and excitons in the bulk and on the surface of MgO has been simulated using the self-consistent semi-empirical intermediate neglect of differential overlap method within an embedded molecular cluster model. The authors results suggest that, while holes are not self-trapped in the bulk of MgO, th…
Infrared absorption spectra are presented for freshly evaporated lead phthalocyanine, oxygen doped lead phthalocyanine and material which has been vacuum annealed. The spectra allow characterization of films for utilization in gas sensors and FET structures.
A new phosphor, K 2 Ca 2 (SO 4 ) 3 :Eu, which is more sensitive than the widely used CaSO 4 :Dy has been recently reported. In this paper the authors present results which demonstrate the effect of various preparation procedures on thermoluminescence sensitivity, including the valence state of the impurity and its pos…
The authors give solutions for spin-lattice relaxation in NQR due to magnetic interactions, generalized for non-axial crystal fields with eta not=0. They find analytic expressions for I=3/2 and give numerical solutions for I=5/2, 7/2 and 9/2. They find that the relaxation curves change considerably with eta . Specific…
The authors present a method for the calculation of the scattering of light by a periodic two-dimensional array of spherical particles adsorbed on a uniform dielectric slab. Multiple scattering of light between the particles of the overlayer and between the overlayer and the substrate is taken fully into account. The…