Materials Literature
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The recombination kinetics of charged carriers in GaAs have been investigated on a picosecond time scale. A pump-probe technique was used to measure reflectivity changes as a function of time up to 900 ps. Initially, (1.2±0.2)×1020 carriers/cm3 were excited into the conduction band. The decay curve indicated dominance…
The authors prove a theorem that relates the energies of unit transmission through a finite, repeated one-dimensional structure to the band structure of the associated infinite lattice formed by periodic repetition of the one-dimensional structure.
We have experimentally discovered that in a nematic liquid crystal subjected to an ac electric field, the first convective structure at low frequencies is in fact a set of oblique rolls, contrary to the accepted picture. We show that it is a new structure with a helical flow motion, and thus lower in symmetry than the…
The origins and development of the concept of carbonaceous mesophase, as derived from discotic aromatic nematic liquid crystals, enable applications to be made to industrial processes. The world availability of pitch materials is such that there is an abundance of pitch which produces cokes of little commercial value.…
A new approach to Preisach's hysteresis model, which emphasizes its phenomenological nature and mathematical generality, is briefly described. Then the theorem which gives the necessary and sufficient conditions for the representation of actual hysteresis nonlinearities by Preisach's model is proven. The significance…
A pulsed plane-wave technique was used to measure the thermophysical properties of the sodium halides under pressure. The thermal conductivity lambda was found to increase with pressure in the 0-4 GPa. The experimental results are compared with the values estimated from the Leibfried-Schlomann model.
A new method for the investigation of methyl group rotation dynamics in free radicals in solids is described, based on the temperature dependence of the methyl protons ENDOR enhancement. The method is shown to work for hindering barriers of any height, and for both radicals trapped in single crystals and in powdered s…
Temperature dependence (4.2-300K) of the static dielectric constant epsilon is reported for two antiferromagnets namely MnF 2 (T N approximately=67.3K) and MnO (T n approximately=118K) for the electric field E parallel and perpendicular to the spin easy axis. Comparison with the temperature variation of epsilon in the…
Two compounds have been synthesized that feature a photosensitive o-nitrobenzyl moiety attached directly to the carbamate nitrogen of carbamoylcholine. The well-characterized acetylcholine analogue, carbamoylcholine, was released from these derivatives in response to laser light pulses at wavelengths between 300 and 3…
Received 15 November 1985DOI:https://doi.org/10.1103/PhysRevLett.56.1509©1986 American Physical Society
The technique of polarization-dependent near-edge x-ray absorption is applid to an interface by taking advantage of core-level and Auger energy shifts for interface atoms. For epitaxial Ca${\mathrm{F}}_{2}$/Si(111) several unoccupied Ca- and F-derived interface states are found. The orientation of the corresponding or…
Speciation calculations for aluminum, in water samples taken from a drainage basin containing acid mine waters, demonstrate a distinct transition from conservative behavior for pH below 4.6 to nonconservative behavior for pH above 4.9. This transition corresponds to the pK for the first hydrolysis constant of the aque…
A Landau-model free energy describing possible ${\mathrm{TaTe}}_{4}$ and ${\mathrm{NbTe}}_{4}$ distorted states resulting from transverse columnar distortions is constructed and analyzed, and solutions corresponding to various commensurate and incommensurate states are found. The possibilities of accounting for the ex…
Abstract In the approach to a cycle‐invariant state in the forced feed concentration cycling of the CO oxidation over a NiO catalyst, a very long transient has been observed lasting 80 ks or more. This transient appears to be associated only with CO pretreatment of the catalyst and is not a general phenomenon. The slo…
Streptomyces hygroscopicus var. jinggangensis produces validamycin, an important antibiotic used in agriculture. It was found that there was a positive correlation between the specific activity of mycelial glutamine synthetase (GS) and validamycin biosynthesis in our laboratory. So, in this paper, the purification, ch…
Abstract Quantitative estimation of matrix‐filler interaction in highly loaded ferrite filled Styrene‐isoprene‐styrene block copolymer has been attempted through dynamic viscoelastic melt studies. A correlation between the interaction parameter in the melt state and that in the solid state at comparable frequency of d…
Основные представления Рѕ переходах металл–диэлектрик РІ соединениях 3d-металлов, Зайцев Р .Рћ., РљСѓР·СЊРјРёРЅ Р•.Р’., Овчинников РЎ.Р“.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTKinetics and equilibria of silver(1+) and lead(2+) cryptates in dimethyl sulfoxideB. G. Cox, J. Garcia-Rosas, H. Schneider, and Ng Van TroungCite this: Inorg. Chem. 1986, 25, 8, 1165–1168Publication Date (Print):April 1, 1986Publication History Published online1 May 2002Publ…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFurther morphological studies of trans-1,4-polyisoprene crystallized from solutionJiarui Xu and Arthur E. WoodwardCite this: Macromolecules 1986, 19, 4, 1114–1118Publication Date (Print):April 1, 1986Publication History Published online1 May 2002Published inissue 1 April 198…
Abstract With a view to discovering new electron donors for low-dimensionally metallic materials, the title compounds were prepared via the corresponding 1,8-dichalcogen-bridged naphthalenes. Their donor characters were examined by cyclic voltammetry, as compared with those of the reference compounds.