Materials Literature
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A novel polyborosilazane was synthesized by reacting per‐hydropolysilazane with trimethyl borate. The chemical structure of this polymer was investigated by the techniques of infrared spectroscopy and nuclear magnetic resonance measurements. Amorphous silicon nitride was obtained by pyrolysis of this polymer in a stre…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStudy of the melting and crystallization behavior of binary poly(.epsilon.-caprolactone)/poly(hydroxy ether of bisphenol A) blendsR. De Juana and M. CortazarCite this: Macromolecules 1993, 26, 5, 1170–1176Publication Date (Print):March 1, 1993Publication History Published on…
Molecular-dynamics calculations are carried out on quartz, ${\mathrm{AlPO}}_{4}$, and ${\mathrm{LiKSO}}_{4}$, which are composed of corner-linked tetrahedra and are known to display crystalline-to-amorphous transitions at 15, 12, and 13 GPa, respectively, at 300 K. The transition occurs when the ${\mathit{T}}_{1}$O${\…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA new photoreceptor molecule from Stentor coeruleusNengbing Tao, Mario Orlando, Jae Seok Hyon, Michael Gross, and Pill Soon SongCite this: J. Am. Chem. Soc. 1993, 115, 6, 2526–2528Publication Date (Print):March 1, 1993Publication History Published online1 May 2002Published i…
A distinction has been made experimentally between the effect on conductivity and tensile strength caused by 1-D mechanical alignment of parent polyaniline films and the effect produced by the combination of physical crosslinking by crystalline domains and associated 1-D nematic-type alignment of amorphous material. A…
Using a lactose permease mutant devoid of Cys residues (C-less permease), Asp237 and Lys358 were replaced with Cys or other amino acids to pursue the proposal that the two residues form a charge pair [King, S. C., Hansen, C. L., & Wilson, T.H. (1991) Biochim. Biophys. Acta 1062, 177-186]. Individual replacement of Asp…
We apply the rigorous electromagnetic grating theory and an electromagnetic wave-propagation model with Kirchhoff boundary conditions to analyze and optimize the performance of arrays of cylindrical dielectric multilevel diffractive lenses. We show that the diffraction efficiency of a high-numerical-aperture lens arra…
To investigate the safety, patient tolerance, and efficacy with 0.3 mmol/kg gadopentetate dimeglumine in magnetic resonance (MR) imaging of the central nervous system (CNS), a phase 3 trial was conducted in 199 patients with suspected CNS lesions. Patients received either 0.1 or 0.3 mmol/kg gadopentate dimeglumine (in…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe first ferromagnetic tetranuclear nickel(II) complex with a .mu.-azido bridge. Structure and magnetic properties of [Ni4(.mu.-N3)4(2-oxo-1,3-diaminopropane)2(2-hydroxo-1,3-diaminopropane)2](ClO4)2Joan Ribas, Montserrat Monfort, Ramon Costa, and Xavier SolansCite this: Ino…
Nitrogen-rich films of carbon nitride were prepared for the first time on silicon wafers and tungsten carbide plates by means of the ion-assisted dynamic mixing (or ion and vapor deposition, IVD) method. The thickness of the films was 1.0 µm and the composition ratio, C/N, was changed from 0.2 to 2.0. The energy of ni…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPressure-induced melting and crystallization of poly(ethylene oxide)Weisheng Li and Maciej RadoszCite this: Macromolecules 1993, 26, 6, 1417–1423Publication Date (Print):March 1, 1993Publication History Published online1 May 2002Published inissue 1 March 1993https://pubs.acs…
This work proposes a method for measureing the diffusion coefficients of water in the ECR (electron cyclotron resonance) plasma CVD SiO 2 used for inter-metal dielectrics. The diffusion coefficients are calculaterd from TPD (temperature programmed desorption) spectra of water measured for a sample SiO 2 /SOG (spin of…
Abstract Eleven cations, Na + , NH + 4 , Cs + , Ag + , Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ , Cu 2+ , Pb 2+ , and Al 3+ , were used individually to extract K from clay fractions of a Korean Ultisol in order to provide information on nonexchangeable K in a 1.4‐nm mineral and mica. The 1.4‐nm mineral and mica. The 1.4‐nm miner…
An application of a magnetostatic 3-D nonlinear finite-element code to the computation of the axial forces on the windings of a large-power autotransformer due to short-circuit currents is described. The analyzed five-limb core autotransformer has an internal tertiary delta-connected winding. A comparison between the…
Abstract There are relatively few well‐documented reports about the mineralogy of Aridisols. A Durorthid and two Haplargids were sampled in the Mojave Desert, California. The soils formed in alluvial deposits estimated to be >300 000, 200 000, and 100 000 yr old, respectively, and were examined for factors influenc…
Abstract The network structure of TBSI-accelerated vulcanization of cis -polyisoprene was studied using C-13 solid-state NMR. The initial crosslink products consisted of A1c ( cis ) and A2c ( cis ) polysulfides. As the percent cure is increased, the A1c and A2c structures reduce in rank to monosulfides, and polysulfid…
For those PTCR materials with higher Pb content, the thermodynamic derivation of increasing values for “inversion temperature” and cation vacancy diffusion rate accounts for the increases in the calculated acceptor‐state densities N s (cm −2 ). The influence of frequency‐dependent properties for the dielectric constan…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHigh-pressure studies of photoluminescence properties of ruthenium(II) polypyridyl complexesJ. M. Lang, Z. A. Dreger, and H. G. DrickamerCite this: J. Phys. Chem. 1993, 97, 10, 2289–2294Publication Date (Print):March 1, 1993Publication History Published online1 May 2002Publi…
Abstract The capture of HCl from cumyl chloride, a model compound for degrading PVC, by epoxidized soybean oil, yielding the related chlorohydrin, is relatively inefficient. The reaction is much accelerated by the presence of metal salts that are primary stabilizers, in particular by zinc carboxylates. In such instanc…
Abstract This work deals with the conductivity of polymer/filler‐mixtures, with the conductive filler particles of colloid size. For the interpretation of the conductivity course in such systems Wessling recently proposed a new thermodynamical percolation model, the so‐called “dynamic boundary model.” A consequence of…