Materials Literature
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Low- and high-angle X-ray diffraction patterns have been obtained from one-dimensional superlattice crystals prepared artificially by alternately depositing predetermined thicknesses of GaAs and AlAs, on the (001) face of a GaAs single-crystal by molecular-beam epitaxy. The positions and intensities of several superla…
Electrochemical polarization measurements were conducted on ASTM A517 Grade F constructional alloy steel in liquid anhydrous ammonia. This steel forms a passive film in ammonia contaminated with oxygen, as evidenced by a noble electrochemical potential. In ammonia free of oxygen, the steel assumes a more active (negat…
The electrical resistivity and elastic constants of slowly cooled single-crystal specimens of the ordered alloy Fe3Si (cubic, DO3 structure) were measured from 4.2 °K to room temperature. The residual resistivity (ρo) was determined to be 0.6 μΩ cm. We infer from this that had the composition been exactly stoichiometr…
The results of tree-initiation tests using impulse voltages show that the time required for the build-up of space charge at 25C is 30μs~80μs. The results of prestressing tests with DC and superimposing impulse voltages show that the space charges are homo-charges. An investigation of tree-initiation in polyethylene wa…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStereochemistry of manganese porphyrins. 2. The toluene solvate of .alpha.,.beta.,.gamma.,.delta.-tetraphenylporphinatomanganese(II) at 20 and -175.degree.CJohn F. Kirner, Christopher A. Reed, and W. Robert ScheidtCite this: J. Am. Chem. Soc. 1977, 99, 4, 1093–1101Publicatio…
The thermal conductivity λ, electrical resistivity ρ, and Seebeck coefficient S of a high-purity Cr specimen (ρ273/ρ4.2=380) were measured from 285 to 1000 K. The ρ and S of two other Cr specimens (ρ273/ρ4.2=380 and 58) were determined from 300 to 1300 K. The ρ and S results from the three specimens are in excellent a…
When used as photo-switches, in data processing technology, etc., photochromic compounds should exhibit a reversible photochromic effect that is as large as possible. The photoreaction (1)⇌(2) of rhodamine derivatives is strictly reversible.
Several previously unavailable parameters of adenosine 3':5'-monophosphate have been determined. The molar extinction coefficient at pH 7.0 is 1.38 X 10(-4), the aqueous solubility at pH 7.0 is 0.0236 M and the diffusion coefficient is 4.44 X 10(-6) cm2/s.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructure of hexaaquairon(III) nitrate trihydrate. Comparison of iron(II) and iron(III) bond lengths in high-spin octahedral environmentsNeil J. Hair and James K. BeattieCite this: Inorg. Chem. 1977, 16, 2, 245–250Publication Date (Print):February 1, 1977Publication History…
4-(trans-4-Alkylcyclohexyl)benzonitriles (1) form nematic phases with higher clearing points and wider temperature intervals than those of the industrially important 4′-alkylbiphenyl-4-carbonitriles
Hard conducting diamond layers were produced by carbon implantation. Above a threshold implantation dose (≃3×1016/cm2), these layers possess the high conductivity of graphite (≃10−2 Ω−1 cm−1) and a hardness intermediate between that of silicon and diamond.
Energy band structures of Gd-pnictides, GdX(X=N, P, As and Sb), known to show a transition from a semiconductor to a metal in the series from GdN to GdSb, are calculated using the APW method. It is found that the energy bands depend sensitively on a choice of the one-electron potential. Then, the calculation is carrie…
Abstract Infrared spectroscopy was used for the quantitative determination of the degree of crystallinity of semicrystalline crosslinked polymeric films with particular application to the characterization of poly(vinyl alcohol) (PVA) networks. The intensity of the 1141 cm −1 band of the IR spectrum of PVA is sensitive…
The experimental evidence for heat transport by magnons in magnetic insulators is reviewed. It is noted that in a thermally isolated system, the magnon temperature comes to equilibrium with the phonon temperature with a finite relaxation time ${\ensuremath{\tau}}_{\mathrm{mp}}$. Since a conventional thermal-conductivi…
The Rietveld profile-analysis refinement procedure [Rietveld, J. Appl. Cryst. (1969), 2 , 65–71] is here applied to microdensitometer-measured Guinier–Hägg X-ray powder film data (strictly monochromated Cu K α 1 radiation). Various functions for describing the profile form of an individual reflection are tested; the m…
Free radical-initiated copolymerization of N-phenyl maleimide (NPMI) with styrene (St), vinyl acetate (VAc) and methyl meth-acrylate (MMA) at 35°C in benzene solution initiated by AIBN was studied. The copolymerization of NPMI and St yields a “nearly equimolecular” alternating copolymer, irrespective of monomer feed.…
A simple model for a nematic liquid crystal is presented, in which the short-range intermolecular repulsions are represented by repulsions between hard spherocylinders, and the (anisotropic) intermolecular attractions are treated self-consistently in the mean field approximation. Using scaled particle theory, an expre…
A survey of the literature on the subject of treeing in solid dielectrics is presented. The purpose is to provide an introduction to the subject, some background for the current research work, and a list of references to some of the more rigorous treatments which in most cases have a narrower scope. The trees which gr…
It is well known that space charge accumulation has a great influence on both the short-time and long-time breakdown strengths of plastic insulation systems operating under direct voltages. In this paper, dc treeing phenomena initiated from the tip of a needle electrode inserted into a polyethylene specimen have been…
Abstract The electrical conductivity and Hall coefficient perpendicular to the c ‐axis of hexagonal MoS 2 , MoSe 2 , and WSe 2 are measured over the temperature ranges 120 to 1170 K and 140 to 820 K, respectively. The derived temperature‐dependent carrier densities are described by n ∼ exp ( –E/kT ) for temperatures l…