Materials Literature
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High-purity silicas synthesized by various manufacturing methods were studied by electron-spin resonance after being irradiated by ArF excimer laser (6.4 eV) at room temperature. E' centers (?Si\ensuremath{\cdot}) are induced in all samples, while nonbridging oxygen hole centers (?Si-O\ensuremath{\cdot}) appear only i…
Affinement dans P nam avec a=23,490, b=21,245, c=4,020 A, Z=4, R=0,077. Discussion de l'arrangement de base des atomes et de la distribution des cations determines par l'affinement d'occupation de site et par l'analyse des liaisons de valence. Comparaison avec les resultats obtenus auparavant
A computational technique is proposed for the analysis of optical absorption spectra for a variety of materials in terms of the well established power law for the optical absorption coefficient. Values of the power index n and optical energy gap E 0 can be obtained from a linear plot using the standard method of numer…
Fabrication and characterisation of photoelectrochemical solar cells employing flux-grown copper tungstate single crystals have been accomplished. Mott-Schottky plots have been drawn to provide a useful estimation of the properties of CuWO 4 from the measurements, and thus the nature and the values of the parameters N…
A synthetic five-part molecular device has been prepared that uses a multistep electron transfer strategy similar to that of photosynthetic organisms to capture light energy and convert it to chemical potential in the form of long-lived charge separation. It consists of two covalently linked porphyrin moieties, one co…
Introduction Molecules have been found to exist in a rich variety of astrophysical environments, including stellar atmospheres, comets, planetary atmospheres, and the dense and diffuse clouds in the interstellar medium. An understanding of molecular structure, spectroscopy, and photoabsorption processes is thus of cri…
The structural bovine eye lens protein alpha-crystallin was dissociated in 7 M urea and its four subunits, A1, A2, B1, and B2, were separated by means of ion-exchange chromatography. Homopolymeric reaggregates of these subunits were prepared by removal of the denaturant via dialysis. It was found that subunits were ex…
We have previously shown [Goto, Y., Calciano, L. J., & Fink, A. L. (1990) Proc. Natl. Acad. Sci. U.S.A. 87, 573-577] that beta-lactamase, cytochrome c, and apomyoglobin are maximally unfolded at pH 2 under conditions of low ionic strength, but a further decrease in pH, by increasing the concentration of HCl, refolds t…
Hydrogen passivation of deep traps in diamond is demonstrated. Current-voltage (I-V) characteristics of polycrystalline thin film and bulk diamond were studied before and after hydrogenation. On hydrogenation, all the samples showed several orders of magnitude increase in conductivity. Hydrogenation was carried out un…
Abstract Understanding the rate dependencies of the tensile strength of reinforcing fibres is a key for the understanding of the rate dependencies of the properties of the corresponding composite materials. Hence, in this study it is attempted to clarify the mechanical responses of aramid and carbon fibres at differen…
Ultraviolet photoelectron spectra (UPS) have been measured for bare unsupported copper clusters in the 1--410 atom size range as mass selected from a supersonic, negatively charged, cluster ion beam. Using an ${\mathrm{F}}_{2}$ excimer laser at 7.9 eV, the UPS patterns display the evolution of the 3d band structure as…
Theoretical and experimental results are reported which provide the first evidence for biexciton states in semiconductor quantum dots. The theory predicts an increasing biexciton binding energy with decreasing dot size. Unlike bulk semiconductors, quantum dots have excited biexciton states which are stable. These biex…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotosensitized electron-transfer reactions and hydrogen evolution in organized microheterogeneous environments: separation of ground-state xanthene-bipyridinium complexes by silica colloidsI. Willner, Y. Eichen, and E. JoselevichCite this: J. Phys. Chem. 1990, 94, 7, 3092–3…
Abstract Composite latex particles based on natural rubber latex have been synthesized to yield materials which may be formally regarded as interpenetrating polymer networks and semiinterpenetrating polymer networks. Methyl methacrylate was added to a carefully stabilized natural rubber latex and polymerized in situ u…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOptical nonlinearities of organometallic structures: aryl and vinyl derivatives of ferroceneSaswati. Ghosal, Marek. Samoc, Paras N. Prasad, and Joseph J. TufarielloCite this: J. Phys. Chem. 1990, 94, 7, 2847–2851Publication Date (Print):April 5, 1990Publication History Publi…
Abstract Catalytic dehydrochlorination (100%) of solid poly(vinyl chloride) (PVC) in the presence of AlCl 3 at 200°C gives a product which has a similar structure to the product of catalytic dehydrochlorination of 1,2‐dichloroethane in the presence of AlCl 3 at 60°C. Both products have brown‐black color, are completel…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructure and reactivity of bimetallic cobalt-vanadium (ConVm) clustersS. Nonose, Y. Sone, K. Onodera, S. Sudo, and K. KayaCite this: J. Phys. Chem. 1990, 94, 7, 2744–2746Publication Date (Print):April 5, 1990Publication History Published online1 May 2002Published inissue 5…
Abstract The dynamic‐mechanical properties of high density polyethylene filled with 20% by volume of untreated glass spheres or glass spheres treated with a silane‐based coupling agent were studied as a function of temperature and imposed tensile deformation. The coupling agent used is capable of providing covalent bo…
Abstract Colorless single crystals of the title compound are grown from mixtures of CsNO 3 , Sb 2 O 3 , and NH 4 H 2 PO 4 at 1173 K. The new compound belongs to the monoclinic space group C2/m with Z = 8. Its crystal structure consists of corner‐ or edge‐sharing SbO 6 octahedra and PO 4 tetrahedra linked to the octahe…
The enzymatic decarboxylation of orotidine 5'-monophosphate may proceed by an addition-elimination mechanism involving a covalently bound intermediate or by elimination of CO2 to generate a nitrogen ylide. In an attempt to distinguish between these two alternatives, 1-(phosphoribosyl)barbituric acid was synthesized wi…