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。
Issues concerning powder consolidation methods compatible with the colloidal approach and issues associated with other powder processing steps, viz., densification and microstructural control, are presented with regard to research directions leading to more reliable ceramics.
Volume 13 of Reviews in Mineralogy presents much of our present-day knowledge of micas. Since 1984 was too much material available to attempt to cover all of the hydrous phyllosilicates in one volume, the micas were treated first because of their abundance in nature and the fact that many detailed studies had been car…
The temperature dependence of Cr 3+ photoluminescence has been measured in the garnets Y 3 Ga 5 O 12 , Gd 3 Sc 2 Al 3 O 12 and Gd 3 Sc 2 Ga 3 O 12 . The observed intensities in the 2 E g to 4 A 2g and 4 T 2g to 4 A 2g emission transitions are interpreted using a model based on the effects of small changes in unit-cell…
Successful growth of (100)ErAs single-crystal films on (100)GaAs has been demonstrated. Reflection high-energy electron diffraction, low-energy electron diffraction (LEED), and Rutherford backscattering with channeling indicate single-crystal growth. LEED from the ErAs shows a (1×1) structure. Overgrowth of GaAs on Er…
Deuterium NMR of nematic droplets in a polymer matrix reveals the effect of confinement on molecular orientational ordering near the nematic-isotropic ($N\ensuremath{-}I$) phase transition. For large droplets of 0.35 \ensuremath{\mu}m in diameter, the $N\ensuremath{-}I$ transition is first order. For droplets of less…
A perovskite-like single-crystal substrate material has been investigated that simultaneously permits epitaxial growth of 1-2-3 superconductor films and possesses desirable rf properties of low dielectric constant and loss tangent. The lattice constant of 3.792 Å provides a lattice match to within 1% of the a axis of…
Abstract The interdependence of electrode wetting and electrode corrosion rate is studied by measuring electrode corrosion rates, passive‐active transition current oscillation amplitudes, and electrode‐electrolyte contact angles for iron electrodes in aqueous H2SO4 solutions of various concentrations and in 1 M H2SO4…
Monte Carlo simulations of diffusion in a lattice gas with both long-range (mean-field) and short-range interactions are presented. Deviations from the conventional site-blocking model are observed, in agreement with experimental data for hydrogen diffusion in Pd. Simulations of multi-site lattice gases, with site-dep…
Superhard boron suboxides, with hardness close to that of diamond, were synthesized from boron/boron oxide mixtures. Such hardness is expected when a material’s molar volume approaches the value characteristic for diamond. These materials consist of boron-rich phases belonging to the boron-oxygen system. The phase whi…
An empirical interatomic potential is introduced, which gives a convenient and relatively accurate description of the structural properties and energetics of carbon, including elastic properties, phonons, polytypes, and defects and migration barriers in diamond and graphite. The potential is applied to study amorphous…
Sufficient work has been made until now on the grain boundaries (GBs) multi-junctions in different polycrystalline cubic materials by using electron microscopy. In the present work the main characteristics of the majority of the junctions reported are theoretically investigated. In fact triple junctions (TJs) show a v…
Electron paramagnetic resonance measurements are reported for Eu2+ ions occupying trigonal sites in Cs2NaYCl6 single crystals. Spin–Hamiltonian parameters are reported at room temperature. A tentative model for the location of the impurity in the lattice is discussed.
The microdynamics of orientational motion (the tumbling of the symmetry axis and the spinning about the axis) of nitrate ions has been investigated in a molecular dynamics simulation of molten LiNO3. Simple Coulomb potential with Born type repulsion has been adopted and all degrees of freedom of vibrating nitrate ions…
The present paper reports the steady-state and transient photoconductivity (${\ensuremath{\sigma}}_{\mathrm{ph}}$) in amorphous thin films of ${\mathrm{Ge}}_{\mathrm{x}}$${\mathrm{Se}}_{100\mathrm{\ensuremath{-}}\mathrm{x}}$. It is observed that the photosensitivity (${\ensuremath{\sigma}}_{\mathrm{ph}/{\ensuremath{\s…
Prolonged exposure to strongly absorbed light increases the ac conductivity (${\ensuremath{\sigma}}_{\mathrm{ac}}$) of well-annealed amorphous ${\mathrm{As}}_{2}$${\mathrm{S}}_{3}$ films, suggesting that new localized states are induced in the band gap. This change is enhanced by low-temperature illumination. Although…
To understand the isotope effect in the ferroelectric phase transition of CsH 2 PO 4 and CsD 2 PO 4 , a quasi-one-dimensional model is proposed. In contrast to the existing models which consider only either the proton's degree of freedom or the polarization dipoles, both of them are regarded as essential elements of t…
The phonon dispersion relations in ferromagnetic Invar alloys, Fe 3 Pt and Fe 65 Ni 35 , have been measured along the high-symmetry directions. The temperature as well as wave number ( q ) dependence of the phonon frequency shift, the linewidth in [110] TA 1 mode, have been observed. The results of these observations…
The electronic states of AlN with excitation energies below about 35 000 cm−1 have been studied at the CASSCF and MRCI levels of theory. Less elaborate calculations have been performed for the low-lying states of AlN+. Although the results are not definitive, they strongly suggest a 3Π ground state for AlN with a very…
The reversible disordering transition of the Ge(111) surface near 1050 K (160 K below the bulk melting temperature) has been studied by low-energy electron diffraction (LEED). Measurements were made using a position-sensitive detection system with the following characteristics: maximum speed, ${10}^{5}$ electrons/sec;…
[C 2 H 10 N 2 ] [CuBr 4 ] cristallise dans P2 1 /a avec a=7,511, b=7,803 et c=8,334 A, β=92,12 o , Z=2; affinement jusqu'a R=0,0392. [C 3 H 12 N 2 ] [CuBr 4 ] cristallise dans P2 1 /n avec a=8,086, b=7,566 et c=17,622 A, β=96,75 o , Z=4; affinement jusqu'a R=0,0359