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 The crystal structure of poly( m ‐phenyulene isophthalamide) was determined by x‐ray analysis. The triclinic cell, with a = 5.27 Å, b = 5.25 Å, c (fiber axis) = 11.3 Å, α = 111.5°, β = 111.4° and γ = 88.0° and space group P 1, contains one monomeric unit. The crystal density is 1.47 g/cc. The molecules in the…
An energy-dispersive x-ray method for a rapid analysis of the broadening of diffraction lines in powder patterns has been developed. Experimental results are given for magnetite powders with sizes in the range 50–200 Å and compared with the results of standard angle-dispersive diffractometry and electron microscopy. T…
The room‐temperature mixed‐mode fracture of commercial hot‐pressed Si 3 N 4 was examined using controlled surface flaws in 4‐point bending, oriented at various angles 6 with respect to the outer fiber tensile stress direction. Catastrophic fracture paths were non‐coplanar with the initial flaw plane, and the stress in…
Free electrolyte was removed by ion exchange from monodisperse polystyrene latex. Non-Newtonian viscosities were measured at volume fractions from 0.05 to 0.50, at various electrolyte concentrations. Electrolytes included HCl, K2SO4, MgSO4, Al2(SO)4)3, and Th(NO3)4. Deionized latices exhibited yield stresses τ0 which…
An electron-spin-resonance (ESR) study has been carried out on γ-ray-induced color centers in a pure-SiO2-core B2O3⋅3SiO2-clad prototype optical fiber and in bulk glasses of the core and cladding compositions. Defects in the core material included the familiar silicon E′ center and other centers tentatively attributed…
Heat capacities of a series of mixed‐alkali glasses of composition (in mol%) 24.4(Na 2 O + K 2 O)‐75.6SiO 2 were measured in the transition region by differential scanning calorimetry. The glass heat capacities at 700 K and the equilibrium liquid heat capacities are the same for all glasses on a per‐g atom basis and e…
<P>Abstract copyright UK Data Service and data collection copyright owner.</P>The Scottish Young People Survey (SYPS), a cohort series, began in 1984, subsuming the Scottish Qualified School Leavers Surveys, (GN 33237). It is a postal survey in which questionnaires are initially sent to young people approximately nine…
Hole trapping in thermally grown silicon-dioxide films has been studied using optically induced hot-hole injection in p-channel polysilicon-SiO2-silicon field-effect-transistor structures. Analysis of the data assuming a uniform trap distribution and no detrapping gives 3.1×10−13 cm2 and 1.4×1018 cm−3 for the capture…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNitrosylmetalloporphyrins. III. Synthesis and molecular stereochemistry of nitrosyl-.alpha.,.beta.,.gamma.,.delta.-tetraphenylporphinato(1-methylimidazole)iron(II)W. Robert Scheidt and Paul L. PiciuloCite this: J. Am. Chem. Soc. 1976, 98, 7, 1913–1919Publication Date (Print)…
New measurements of the optical spectrum of trivalent neodymium in a hexagonal lanthanum chloride host have been made at 4 and 77 K at wavelengths down to 2500 Å (40 000 cm−1). Crystal quantum number assignments for new energy levels were derived from these results and for most of the earlier levels not already classi…
One of the important problems in the development of ac plasma panels is to produce panels that maintain stable characteristics for a long time. A new idea for using a protecting layer over the dielectric layer which isolates the electrodes from the gas was examined and good results were obtained. Moreover, besides sta…
The analysis of Rapini and Papoular for homeotropic and homogeneous geometries is extended to predict the effects of weak boundary coupling on liquid-crystal display performance. An implicit expression for deformation as a function of applied field is derived for the case of equal elastic constants. Steeper transition…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTChemistry of the Cure of Poly(p-phenylene sulfide)Richard T. HawkinsCite this: Macromolecules 1976, 9, 2, 189–194Publication Date (Print):March 1, 1976Publication History Published online1 May 2002Published inissue 1 March 1976https://pubs.acs.org/doi/10.1021/ma60050a001http…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPolyurethane Interpenetrating Polymer Networks. I. Synthesis and Morphology of Polyurethane-Poly(methyl methacrylate) Interpenetrating Polymer NetworksS. C. Kim, D. Klempner, K. S. Frisch, W. Radigan, and H. L. FrischCite this: Macromolecules 1976, 9, 2, 258–263Publication D…
No abstract available.
The 'transition' state in binary f.c.c. based systems is assumed to be characterized by the repetition of interpenetrating polyhedral clusters of atoms occupying lattice sites and having the macroscopic composition. Its mathematical formulation leads to relations between the short-range order (SRO) coefficients, which…
Summary The equilibria as well as the rates of adsorption and desorption of the ions Pb 2+ , Cu 2+ , Cd 2+ , Zn 2+ , and Ca 2+ by soil organic matter were determined in batch experiments as a function of the amount of metal ions added to an aqueous suspension of HCl‐washed peat. Simultaneous determination of the metal…
The withstand strength of contaminated insulators under practical field conditions depends on the type and distribution of contaminants as well as their conductivity. In this paper, the authors have investigated the dependence of flashover voltage on the chemical composition of multicomponent contaminants and have pro…
Mossbauer spectra on 57Fe and 119Sn in perovskite carbides with formula M3M'C (where M is Fe or Mn, and M', Al, Ga, Ge, Zn, Sn) have been observed. All those compounds are characterized by a large quadrupole coupling amounting to 1.3 mm s-1 and by low internal magnetic fields, around 70 kOe, at M atom. The effect of c…
The changes of the elastic shear moduli C 44 and C'=(C 11 -C 12 )/2 have been measured after electron irradiation of aluminium at 4.5K. Aside from dislocation pinning, a diaelastic effect which is proportional to the radiation-induced defect density has been observed. From these data the diaelastic polarizabilities un…