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 information contained in an Auger-electron-photoelectron coincidence spectroscopy (AEPECS) experiment for $\mathrm{XXV}$, $\mathrm{XYV}$, and $\mathrm{XYZ}$ Auger processes when a single $X$ level is involved is discussed. For finite systems AEPECS gives information about the spatial character of the excited state…
Abstract PE spectral comparisons of the title compounds with the corresponding O ‐ and N ‐methyl fixed derivatives show that both 2‐ and 4‐quinolone exist as the NH forms in the vapour phase: none of the OH tautomers could be detected.
Evidence for superconductivity in the organic conductor di-(tetramethyltetraselenafulvalenium)-perchlorate [${(\mathrm{TMTSF})}_{2}$Cl${\mathrm{O}}_{4}$] has been found by resistance measurements in the absence of applied pressure. For different crystals the transitions are approximately 0.3 K wide and are centered ar…
Polarised Raman spectra of chloro- and bromo-sodalite (Na 4 Al 3 (SiO 4 ) 3 Br) 2 single crystals have been recorded, and 28 of the predicted 32 Raman-active phonon modes observed. A full group-theoretical analysis of the zone-centre phonons is given. The internal modes are assigned using as a basis the normal mode fr…
Abstract A historical survey about the development of Ziegler‐Natta catalysts for polymerization of propylene is given. After having employed catalysts based on titaniumtrichloride for several years, in the 70's catalysts of the so‐called second generation were introduced, which are more effective and yield products o…
New developments in Cu2S thin-film technology allow, in principle, the combination of Cu2S with semiconductors other than CdS or Cd1−xZnxS for solar cell purposes. We discuss here a pn+-type Cu2S-ZnO structure that offers some basic advantages over existing structures. Our analysis predicts a practically achievable ef…
Natural ultramarine and alkali borate glasses doped with sulphur are investigated by means of ESR and optical spectroscopy. A comparison of optical and ESR spectra makes it possible to conclude that the blue colouring (absorption band within the range 585 nm) and the anisotropic ESR signal (g1 = 2.003, g2 = 2.032, g3…
The macroscopic properties of the plastic deformation of a simple model crystal which obeys the Friedel relation are compared with computer simulation data and some in the literature unnoticed differences are discussed. It is pointed out that the random distribution of obstacles causes on average activation energy ΔG0…
There is increasing interest in the measurements of the dielectric absorption of compressed solid powders. A theoretical analysis is reported which highlights the problems which may arise due to “lack of contact” between the material and the electrodes. It is demonstrated, both theoretically and experimentally, that s…
It is observed that a reversible step period rearrangement on clean nickel single-crystal surfaces occurs in the immediate vicinity of the Curie temperature. Reversible carbon segregation is observed on the same crystal surfaces below the Curie point. The segregated carbon is carbidic, not graphitic, and indicates a c…
Magnetic and crystallographic nature of the compounds NiMnGe1−nSin (0 ≦ n ≦ 1) are studied in the temperature range from 80 to 1000 K by X-ray and neutron diffraction, magnetometric and DTA measurements. On the basis of these experimental data, crystallographic and magnetic phase diagram are constructed. The compounds…
A theoretical study of topological excitations (kinks) in a one-dimensional one-third-filled Peierls system is presented. The charges associated with the kinks are found to be fractional $Q=\ifmmode\pm\else\textpm\fi{}\frac{1}{3}e,\ifmmode\pm\else\textpm\fi{}\frac{2}{3}e$. Calculations of the spatial widths and electr…
A theory for geminate electron-hole recombination in amorphous semiconductors is given, which includes the effects of both diffusion and tunneling. The exact solution of the model is obtained neglecting the Coulomb interaction, which is included later in the prescribed diffusion approximation. It is shown that any com…
A comprehensive study of the Rayleigh–Brillouin scattering spectra of o-terphenyl in the liquid and supercooled liquid state has been carried out. Anomalies in the Brillouin frequency and linewidth data are observed at the glass transition temperature (Tg) and at a temperature (TK) about 36 K higher than the melting p…
The gaseous molecules VC, NbC, NbC2, MoC, and MoC2 have been identified in a mass spectrometric study of the Knudsen effusate from the niobium–graphite and vanadium–niobium–molybdenum–graphite systems at high temperatures. Third-law enthalpies of the various reactions involving these species were determined from the e…
We report static magnetization measurements on the compositionally modulated ferromagnetic alloy Cu/Ni, which, contrary to earlier ferromagnetic resonance measurements, show the moment per Ni atom is reduced relative to pure Ni. The low-temperature magnetization is found to vary linearly with modulation amplitude, but…
Sensitivity analysis is considered for kinetics problems defined in the space–time domain. This extends an earlier temporal Green’s function method to handle calculations of elementary functional sensitivities dui/daj where ui is the ith species concentration and aj is the jth system parameter. The system parameters i…
We show that the spontaneous decay of a phonon by anharmonic processes of any order into a set of phonons of higher phase velocity is impossible for both $N$ and $U$ processes. The result is valid for crystals of arbitrary symmetry and anisotropy and in the presence of frequency and angular dispersion. The implication…
Extended-x-ray-absorption-fine-structure (EXAFS) data on the normal and superionic phases of AgI and the cuprous halides have been analyzed using four structural models: harmonic oscillator, displaced site, anharmonic oscillator, and excluded volume. The most satisfactory description is obtained with the last model, b…
Structural defects in glassy ${\mathrm{As}}_{2}$${\mathrm{Se}}_{3}$ are classified and labeled according to the constituent like-atom bonds and malcoordinated atoms. A selection rule is formulated to reduce the number of allowed Fermi-level pinning reactions. An elementary Bethe-lattice model is introduced as a starti…