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 emission spectrum of Tb3+ substituted in YAG to various concentrations (x in Y3−xTbxAl5O12 ranges from 3×10−5 to 3×10−1) has been measured on samples prepared by two different methods. These methods are powder preparation by coprecipitation and growth of crystalline layers by liquid-phase epitaxy. The spectrum con…
The previously postulated production of holes during the electrical breakdown of varistors has been directly verified. In some compositions band-gap (3.2 eV) luminescence from the recombination of these holes with free electrons has been observed. The intensity of this luminescence is greater in varistor compositions…
We have performed an extended x-ray-absorption fine-structure (EXAFS) measurement of ${\mathrm{Cd}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{Mn}}_{\mathrm{x}}$Te solid solutions for various concentrations x in the single-phase range 0\ensuremath{\le}x\ensuremath{\le}0.7. Data have been collected on the Mn K, Cd…
The physical and electronic properties of poly(isothianaphthene) PITN, are reported, including initial characterization, electrochemical cyclic voltammetry, spectroscopy, and transport properties. PITN has the smallest energy gap of any known conjugated organic polymer, Eg≂1 eV. This novel conjugated polymer exhibits…
The light stabilization of polypropylene (PP) fibers places special requirements on the stabilization system due to the high surface to volume ratio, the severe processing conditions, and the post spinning treatments. Earlier systems provided only moderate performance lifetimes thus limiting the markets for PP fibers.…
The properties of hindered diazacycloalkanones were evaluated as light stabilizers and antioxidants for polypropylene. A totally hindered piperazinone was found to be excellent light stabilizer with many other desirable properties as a polymer additive. Partially hindered decahydroquinoxalinone derivatives were found…
Since their initial production by our laboratories about ten years ago, hindered amine light stabilizers (HALS) have become established as excellent light stabilizers of polymers. This review deals with their synthesis, evaluation and development.
Although polyethylene is essentially nonbiodegradable, it was found that copolymers of ethylene and 2-methylene-1,3-dioxepane prepared by a high pressure free radical solution polymerization were indeed biodegradable. Most synthetic polymers are not biodegradable because they have not been on the earth long enough to…
The absolute energy of the Lyman- alpha 1 line of hydrogen-like krypton has been measured with an accuracy of 36 p.p.m. The ions were produced at GANIL (Caen) and the X-rays emitted in flight detected with a flat crystal spectrometer. The (1s) Lamb shift of hydrogen-like krypton has been found to be 11.95+or-0.5 eV in…
Absolute elastic and inelastic differential cross sections for electrons scattered from methane and ethane have been measured for incident electron energies from 7.5 to 20 eV and scattering angles from 32 degrees to 142 degrees . The measurements were made using an electron spectrometer, incorporating hemispherical el…
The hindered amine story is an interesting success story involving participation by scientists throughout the world. The success of hindered amines has partly been due to the free exchange of information among scientists, so that the accomplishments of one group, studying stable free radicals, could be picked up by th…
It is shown that a decaying vacancy is able to give an isolated line in an atomic or molecular photoelectron spectrum although the usual condition of validity of the quasi-particle approximation is violated. A more general condition is proposed which is based on the ability of the one-hole Green's function expansion i…
The authors have developed an arbitrary-collision sampling technique for Monte Carlo calculations of the diffusion term in the density gradient expanded energy distribution functions. The technique is shown to provide for an alternative and accurate Monte Carlo calculation of the diffusion coefficients. Comparisons of…
The mechanism of irreversible thermoinactivation of an enzyme has been quantitatively elucidated in the pH range relevant to enzymatic catalysis. The processes causing irreversible inactivation of hen egg-white lysozyme at 100 degrees C are deamidation of asparagine residues, hydrolysis of peptide bonds at aspartic ac…
Recent studies of the adsorptive and catalytic properties of magnetite (Fe 3 O 4 ) are discussed with respect to the water-gas shift reaction (WGS) in this review article. Proposed mechanisms are examined, and the properties of the active sites required for these mechanisms are considered. Kinetic relaxation measureme…
Alkali and barium hydroxide promotion of the Cu/ZnO methanol synthesis catalysts has been investigated with the following results: (i) at low temperatures, high H 2 /CO ratios, water-free and CO 2 -free synthesis gas, the alkali promote methanol synthesis rates in the order Cs>Rb>K>Na>Li; (ii) the alkali hydroxides ar…
Abstract 11,11,12,12‐Tetracyan‐9,10‐anthrachinodimethan [ 3a , X = C(CN) 2 ] besitzt im Kristall eine stark von der Planarität der Stammverbindung Anthrachinon abweichende Geometrie. Der Winkel zwischen den beiden Benzoanellanden beträgt 145°; die Dicyanmethylen‐Einheiten sind entgegengesetzt gefaltet und schließen ei…
A microdynamic theory for the self-diffusion coefficient, which involves a wave-number-dependent viscosity, eta (q), is successfully tested on a hard-sphere system. The models the authors introduce for eta (q) are adapted to the Lennard-Jones fluid. New molecular dynamics data for the relative diffusion coefficient, i…
Stage purity and staging transitions of potassium-graphite intercalation compounds have been investigated in situ by high-resolution x-ray scattering. The positions and profiles of ($00L$) Bragg reflections indicate staging disorder in thermal equilibrium for all compounds larger than stage 2, which increases with inc…
We report electron-microscopy and high-resolution x-ray-scattering measurements of rapidly quenched ${\mathrm{Al}}_{6}$Mn. The electron-diffraction pattern shows icosahedral symmetry. Peaks in the x-ray-diffraction pattern can be indexed to a mixture of fcc Al and a phase whose reciprocal lattice is described by a sum…