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。
Abstract Oriented amylose fibers in the V form were prepared and subjected to x‐ray analysis. Unit cells and the probable space group of P2 1 2 1 2 1 were determined for the V anhydrous and V hydrate forms of amylose; the analysis confirms previous predictions of these structures based on x‐ray powder patterns. Chain…
Abstract The thermal stability and degradation process for a specific poly(aryl ether) system have been studied. In particular, the polymer which is available from Union Carbide Corporation as Bakelite polysulfone has been examined in detail. Polysulfone can be prepared from 2,2‐bis(4‐hydroxyphenyl)propane and 4,4′‐di…
The concentration of argon in sputtered nickel films has been obtained as a function of the film-growth temperature, the discharge pressure, and of the energy (bias voltage) with which the argon ions bombard the growing film. The concentrations vary from about 10−1 argon atoms/Ni atom to 10−4 argon atoms/Ni atom, depe…
Abstract Stabilization of metastable aragonite and Mg-calcites is an inevitable process and constitutes a large and important part of carbonate diagenesis. Stabilization can occur in only a limited number of ways. "Solid state" stabilization takes place by inversion or exsolution for aragonite and Mg-calcite, respecti…
Not available
Not available
Not available
Not available
Not available
Not available
Not available
The temperature dependence of the second-order Raman spectrum of SrTiO3 and KTaO3 has been observed over the temperature range 4°—473°K using the mercury 4358-Å exciting line. From group-theoretical arguments for cubic perovskite lattices the spectra have been interpreted in terms of phonon pairs at critical points in…
The electron spin resonance of F 3+ in single crystals of SrTiO 3 has been studied in the low temperature phase below 110°K. The resonance lines exhibited small splitting in addition to the usual tetragonal splitting. The orientation dependence of the splitting was measured at 77°K and at 4.2°K. The whole spectrum is…
Abstract A series of new aromatic polyethers have been prepared by solution condensation polymerization. The synthesis involves the condensation of a dialkali metal salt of a dihydric phenol with an “activated” or negatively substituted aromatic dihalide in an anhydrous dipolar aprotic solvent at elevated temperatures…
Abstract The frequencies of normal modes propagating in the high symmetry directions, [001], [110] and [111], of lead sulphide have been measured by inelastic neutron scattering techniques. A marked decrease in the value of the longitudinal optic mode frequency has been observed at small wavevectors. A similar effect…
In the morphogenesis of embryonic feather germs the formation of dermal cell groupings is associated with the development of a highly regular pattern of birefringence in the dermis. This birefringence is due to a lattice-like system of collagenous tracts along which dermal cells become progressively aligned and groupe…
The cross section for production of electron pairs by unpolarized photons in the field of an electron is calculated. The total cross section is obtained by numerical integration. The contributions to the total cross section from different diagrams (exchange and $\ensuremath{\gamma}\ensuremath{-}e$ terms) are calculate…
Compared to homologous tissues from adult animals, rapidly growing embryonic and fetal tissues contain large amounts of collagen proline hydroxylase. Lung and skin from scorbutic guinea pigs contain one-third as much enzyme as normal tissues do. A rapid increase in proline hydroxylase occurs on the 2nd day of formatio…
The self-consistent charge distribution in covalently bonded crystals and molecules is divided into two components, an atomic and a bonding part. Both can be calculated in elemental crystals from macroscopic dielectric properties. The theory is easily generalized to treat heteropolar and anisotropic effects, lattice v…