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 hydrolysis of aluminum-tri-(sec-butoxide), ASB, in ionic and nonionic media is shown to be a useful method for the synthesis of aluminum minerals. Infrared and X-ray analysis were used to identify the reaction products. Pseudoboehmite is formed at low water to aluminum ratios. At higher water content, tra…
Abstract The carotenoids astaxanthin, lutein and zeaxanthin form high molecular weight aggregates in aqueous solvent systems. The absorption spectra of the aggregates, compared to those of the monomer molecules, show significant bandwidth narrowing and blue shifts of 600–800 Å. The resonance Raman spectra of these agg…
The ultraviolet absorption cross sections of HgI2, HgBr2, and tin (II) halide vapors in the region 200–400 nm have been measured. The cross sections for the tin (II) halides are higher than the mercury (II) halides. The various ground and excited state HgX, SnX radicals, and X atoms (X=I, Br, Cl) produced as a result…
Measurements of the efficiencies of electromagnetic generation and detection of ultrasonic Lamb waves in Armco iron, 1018 steel, nickel, and Invar are presented as a function of both the static and dynamic magnetic field strengths in a geometry in which both are parallel to the surface. Three distinct coupling mechani…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTChromium(III) porphyrins. Chemical and spectroscopic properties of chloro-meso-tetraphenylporphinatochromium(III) in nonaqueous solutionsDavid A. Summerville, Robert D. Jones, Brian M. Hoffman, and Fred BasoloCite this: J. Am. Chem. Soc. 1977, 99, 25, 8195–8202Publication Da…
Raman backscattering from oxidized GaAs and InAs yielded two anomalous peaks of large scattering strength which we have concluded to be from excess As in the interface between the oxides and underlying semiconductors. Similarly, we concluded that the two anomalous peaks from GaSb and InSb are from excess interface Sb.…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTBinuclear complexes of macrocyclic ligands. A mixed-valence copper(II)-copper(I) complex which exhibits unusual temperature-dependent behaviorRobert R. Gagne, Carl A. Koval, and Thomas J. SmithCite this: J. Am. Chem. Soc. 1977, 99, 25, 8367–8368Publication Date (Print):Decem…
Infrared spectra of some poly(methylene terephthalates) and some poly(methylene 2,6-naphthalates) were compared. To interpret the spectral changes during drawing and heat treatment, the concept of rotational isomerism of the O-(CH2)M-O part, which was fairly successful in poly(ethylene terephthalate) (C2T), was trie…
The redox reaction of 1,1′‐diheptyl‐4,4′‐dipyridinium dibromide in water was investigated by means of linear potential sweep voltammetry. It was found that aging of the radical salt film or the occurrence of the second reduction step results in an additional oxidation peak. This additional oxidation peak is accompanie…
The tunnel splitting of the librational ground state of a NH+4 ion in (NH4)2 SnCl6 has been analyzed by ’’incoherent’’ inelastic neutron scattering. Ground state splittings of 2.96±0.04 and 1.51±0.03 μeV have been observed at T=6 K and are interpreted as transitions between A?T and T?E spin symmetry states, respective…
Dipole oscillator strength distributions (DOSDs) have been constructed for ground state Li, N, O, H 2 , N 2 , O 2 , NH 3 , H 2 O, NO, and N 2 O by using experimental and theoretical photoabsoiption and high energy electron inelastic scattering cross sections. Each DOSD is required to satisfy the Thomas–Reiche–Kuhn sum…
Abstract In most low‐strength applications, plastics offer cost, maintenance, and density advantages over metals. Major deficiencies of plastics, however, are low thermal and electrical conductivities. Various studies have dealt with these problems, and it has been found that thermal conductivity and electrical conduc…
Abstract The intensity distribution of the N K‐emission band of hexagonal boron nitride samples with partially oriented crystallites is found to be strongly dependent upon the take‐off angle of the emitted radiation. The obserbed emission bands can be separated unambiguously into a σ‐ and a ‐subband. On the basis of t…
Abstract Amorphous hydroxides of Al, Fe, Mn, Mg, Zn, Co, Ni, etc., are capable of coprecipitating SiO 2 even from very dilute (weathering) solutions. Silica minerals form only in those precipitates from solutions undersaturated with respect to amorphous silica (100 ppm SiO 2 at 20°C). With higher SiO 2 concentrations…
An electric-field-induced cholesteric-nematic transition on a sample containing a europium chelate guest molecule of little or no polarization shows contrast ratios as high as 9 : 1 for its brilliant red (612 nm) fluorescence.
Coefficients of linear thermal expansion are reported, in the range 60 K to room temperature, for eight optical materials: Polytran potassium chloride and Polytran calcium fluoride-Harshaw; chemical-vapor-deposited (CVD) zinc sulfide and zinc selenide-Raytheon; germanium (single-crystal and polycrystal); crystalline m…
Raman scattering in single crystals of ${\mathrm{V}}_{2}$${\mathrm{O}}_{3}$ has been studied in the range from \ensuremath{\sim}20 K to room temperature. Metal to insulator, crystallographic, and antiferromagnetic-ordering transitions take place concurrently at ${T}_{t}\ensuremath{\sim}150$ K. The observed spectra sho…
Charge transfer between two insulators, or between a metal and an insulator, is not influenced by previous identical contacts. Since it has recently been shown that material transfer occurs to a large extent on the first contact and to a much smaller extent on subsequent contacts, it can be concluded that material tra…
Abstract A mixing‐reaction model (MIRE) is used to develop criteria, readily accessible by experiment, which permit the chemist to decide whether and when mixing effects influence the product distribution in competitive consecutive or parallel reactions. The validity of these criteria is demonstrated by comparison of…
Radial expansion and subsequent fracture into segments of thin-walled cylindrical shells at large initial strain rates are studied analytically and experimentally. The theory of probability along with a description of relief wave propagation away from each fracture is used to formulate a theory which predicts the numb…