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。
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTBonding in dye aggregates. Energetics of the dimerization of aqueous cobalt(II)-4,4',4'',4'''-tetrasulfophthalocyanine ionZ. A. Schelly, D. J. Harward, Paul Hemmes, and Edward M. EyringCite this: J. Phys. Chem. 1970, 74, 16, 3040–3042Publication Date (Print):August 1, 1970Pu…
A method has been developed for calculating the effective complex permittivity of a solid dielectric arising from the motion of charge carriers which are blocked at the electrodes. The method makes use of computer simulation of the motion of the charge carriers and is valid for high voltages. Results are given of calc…
Abstract A new class of high molecular weight polyarylsulfones is described. Polymer synthesis and structure–property relationships are discussed. The polymers are prepared by Friedel‐Crafts type polycondensation of aromatic sulfonyl chlorides with aromatic hydrocarbons. A number of Lewis acids in small quantities are…
The Green's function method developed by Mahan for excitons is extended to the case that the interaction is not instantaneous. Energy corrections to the exciton due to recoil effects, retardation effects, renormalization constants and vertex parts arising from the interactions of an electron and a hole forming an exci…
The elastic properties of Mn${\mathrm{F}}_{2}$ have been investigated in the temperature range $4.2<T<330$ K using a cw transmission technique. The measured values at $T=300$ K of the six adiabatic elastic constants in units of ${10}^{11}$ dyn/${\mathrm{cm}}^{2}$ are ${c}_{11}=10.24$, ${c}_{33}=16.55$, ${c}_{44}…
Results are presented of a study of x-ray and electron excited luminescence in all alkali halides in the temperature range 4K to 300K. Details are given of the spectral distribution and lifetimes associated with the luminescence bands at about 5K. The lifetime and peak intensities of some bands have been measured as a…
Nickel self-diffusion and semiconductivity in single-crystal NiO have been measured as functions of temperature and O2 pressure over ranges of 1182–1762°C and from one to 5 × 10−7 atm. Atmospheres of pure O2, pure CO2, O2–Ar mixtures, and CO–CO2 mixtures have been used. In pure O2 and in pure CO2 the results can be ex…
Infrared spectroscopy has been used to show that the surface hydroxyl groups on highly dehydrated silica will exchange with 18 O-labeled water. The degree of exchange depends on the sample temperature and is a maximum at about 400 °C, where approximately 65% of the silanol groups contain 18 O. The use of the 18 O exch…
Low carbon 10-19% Ni-Fe alloys become considerably more resistant to hydrogen cracking after severe cold rolling. The observed resistance decreases with increasing carbon content. The improvement is directional, the optimum effect applying to specimens stressed parallel to the rolling direction. Other iron alloys, e.g…
Abstract The Diels‐Alder homopolycycloaddition of 2,5‐diphenyl‐3,4‐(5,6‐acenaphthylenylene)‐cyclopentadienone (VIII) affords a low molecular weight soluble ladder polymer having reduced specific viscosities between 0.17 and 0.25 dl/g in benzene and an insoluble fraction of higher molecular weight. The ladder polymers…
The energy levels of the I5 ground term of Ho3+ in single crystals of CaWO4 were established by absorption and fluorescence spectra measurements. The measurements were made using crystals at temperatures near 2, 20, and 85°K. Most of the observed transitions can be accounted for by the electric dipole selection rules.…
Measurements of the Mn 55 nuclear magnetic resonance, high-field susceptibility, magnetic anisotropy and electrical resistivity have been performed on intermetallic compound MnB 2 . It is proposed that MnB 2 is an antiferromagnet with a magnetic moment of about 3 µ B per Mn atom and a Néel point of 760°K. The weak fer…
Abstract Certain monocyclic and polycyclic tertiary amines initiate polymerization of, and copolymerize with, pivalolactone. These comprise three‐, four‐, and five‐membered monocyclic amines and 1‐azapolycyclic amines. The polymerization proceeds in three steps: (a) initiation to form a cyclic amine/pivalate betaine,…
The zero-field NMR of Mn 55 in ferromagnetic MnBi has been observed in the temperature range 4.2°K to 500°K. Resonance signals from nuclei in the domain and domain wall are separately observed at 225.01 MHz, and 206 MHz, respectively, at 294°K. As the temperature is decreased, the quadrupole splitting and the frequenc…
The pressure coefficient of the Curie temperature of CuCr 2 X 4 was obtained from the result of measurement of the variation with pressure in the self inductance of search coil wounded on the specimen vessel. The coefficients, d T c /d p , were founded to be -11.3×10 -4 °Kkg -1 cm 2 for CuCr 2 S 4 , -4.1×10 -4 °Kkg -1…
It is proposed that the various localized forms of corrosion (pitting, stress corrosion cracking, intergranular corrosion, crevice corrosion, filiform corrosion, tuberculation, and exfoliation) have the common feature of local acidification by hydrolysis. The acidity is viewed as having a responsible role in the self-…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEffects of central and terminal groups on nematic mesophase stabilityMichael J. S. Dewar and Ronald S. GoldbergCite this: J. Org. Chem. 1970, 35, 8, 2711–2715Publication Date (Print):August 1, 1970Publication History Published online1 May 2002Published inissue 1 August 1970h…
Abstract Critical miscibility data obtained from measurements of phase‐volume ratios have been used to calculate the concentration dependence of the pair interaction parameter for the system polystyrene–cyclohexane. The measured temperature and concentration ranges are 11–30°C and 4–18% polymer by weight, respectively…
Electrical conductivity and Hall effect measurements have been made on a series of synthetic p-type semiconducting diamonds in the temperature range 80 to 450K. The dominant conductivity mechanism at low temperatures is shown to be impurity conduction, and effects have been isolated due both to impurity-band conductio…
Abstract The thioketo and thioenol tautomers of thioacetone have been separated by gas chromatography and characterized by infrared and NMR spectra at low temperatures. The pure thioketo tautomer polymerizes rapidly at room temperature, but the thioenol tautomer does not. At room temperature, the thioenol gradually di…