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Abstract A torque rheometer method has been developed to evaluate the melt behavior of biopolyesters. The main features of this technique include: (i) a modified equipment configuration, so as to maintain the melt temperature within ± 1°C pf the set temperature after the first few minutes of polymer melting and therma…
The structural and electronic properties of the zinc-blende, beta -Sn and rock-salt phases of BP are calculated within the local-density approximation. Two competing methods-LMTO and the pseudopotential plane-wave method-have been used. The agreement between the two electronic structure methods is excellent. We obtain…
Abstract Generation of the molecular electrostatic potential (MEP) profiles, in color‐coded form, on the solvent‐accessible contact surfaces of the two main conformations that sucrose adopts in vacuo as well as in aprotic solvents (e.g. DMF), clearly shows the secondary glucosyl‐2‐OH to be the most electropositive of…
The six-dimensional framework developed by Stroh to treat the elasticity theory of dislocations in crystals has been extended to a twelve-dimensional formalism in quasicrystals. The elastic fields induced by a straight dislocation line in quasicrystals are given in terms of integral representations, which may be suita…
The microfocus X-ray beamline at the European Synchrotron Radiation Facility has been used to investigate the variation in molecular orientation and crystallinity in spherulites of the organic polymer poly-3-hydroxybutyrate (PHB). This is the first report of the correlation of optical and X-ray measurements on spherul…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPoly(ureidosilazanes): Preceramic Polymeric Precursors for Silicon Carbonitride and Silicon Nitride. Synthesis, Characterization, and Pyrolytic Conversion to Si3N4/SiC CeramicsDietmar Seyferth, Carsten Strohmann, Neal R. Dando, and Anthony J. PerrottaCite this: Chem. Mater.…
An iterative algorithm has been developed that takes starting values derived by an envelope method but then minimizes the influence of the envelopes and emphasizes the actual measured data. This combination avoids the difficulties inherent in the accurate drawing of the envelopes and makes it possible to extract the t…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis of Colloidal Polypyrrole Particles Using Reactive Polymeric StabilizersM. R. Simmons, P. A. Chaloner, and S. P. ArmesCite this: Langmuir 1995, 11, 11, 4222–4224Publication Date (Print):November 1, 1995Publication History Published online1 May 2002Published inissue…
The mid-infrared absorption spectra (400–1200 cm −1 ) of four TiO 2 -bearing crystalline solids, in the form of rutile (TiO 2 ), Na-titanates (Na 2 Ti 6 O 13 / Na 2 Ti 3 O 7 ), and natisite (Na 2 TiOSiO 4 ), are presented, providing a clear illustration of their differences in IR band structure (band pattern). Two sha…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNew Lariat Ether-Type Macrocycles with Cyclophosphazene SubunitsKrystyna Brandt, Iwona Porwolik, Teobald Kupka, Anna Olejnik, Robert A. Shaw, and David B. DaviesCite this: J. Org. Chem. 1995, 60, 23, 7433–7438Publication Date (Print):November 1, 1995Publication History Publi…
The flightless locus of Drosophila melanogaster has been analyzed at the genetic, molecular, ultrastructural and comparative crystallographic levels. The gene encodes a single transcript encoding a protein consisting of a leucine-rich amino terminal half and a carboxyterminal half with high sequence similarity to gels…
We report on the optical reflective properties of the planar texture of cholesteric liquid crystal reflective displays. The reflecting liquid-crystal medium is partitioned into many distinguishable domains, each of which is characterized by its local dielectric anisotropy. Such a multidomain cholesteric liquid crystal…
Wheat germ agglutinin isolectin 3 (WGA3) was crystallized from 10 mM acetate buffer at pH 4.9 containing 6 mM CaCl(2) and 4%(v/v) ethanol. The crystal belongs to monoclinic space group P2(1) with unit-cell dimensions a = 44.86, b = 91.02, c = 44.86 A, and beta = 110.22 degrees. The asymmetric unit contains two molecul…
Abstract The infrared and Raman spectra of L ‐asparagine and ND 3 + , ND 2 ‐ L ‐asparagine as solid samples were recorded. The data obtained were used to propose a general assignment of the fundamental vibrational modes on the basis of the measured isotopic shifts and correlations with previous data reported for other…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTApplication of Secondary Nucleation Theory to Semirigid Macromolecules: PEEK, PET, and PENF. J. Medellin-Rodriguez, P. J. Phillips, and J. S. LinCite this: Macromolecules 1995, 28, 23, 7744–7755Publication Date (Print):November 1, 1995Publication History Published online1 Ma…
Elastic instabilities have been used to explain the occurrence of amorphization in both \ensuremath{\alpha}-quartz (${\mathrm{SiO}}_{2}$) and \ensuremath{\alpha}-berlinite (${\mathrm{AlPO}}_{4}$). However, there is a dynamical instability at (1/3,1/3,0) in the Brillouin zone preceding the elastic instability for both…
The low-temperature specific heat of the organic conductors \ensuremath{\alpha}-(BEDT-TTF${)}_{2}$MHg(SCN${)}_{4}$ (M=K, Rb, and ${\mathrm{NH}}_{4}$) has been measured at temperatures down to 0.25 K and under magnetic field up to 8 T. The electronic specific-heat coefficient \ensuremath{\gamma} is estimated at 7.0\ifm…
A new type of vanadium oxide ( V 2 O 5 ‐ n H 2 O ) with a structure intermediate between the amorphous and the crystalline state is synthesized by a reaction of metallic vanadium with hydrogen peroxide. Its electrochemical properties in relation to lithium intercalation have been investigated in a 1 M LiClO 4 / propyl…
Results from a plasma chemistry model provide predictions of spatially and temporally averaged plasma properties. Application of the model to chlorine-etch process conditions, typical of a high plasma-density transformer coupled plasma reactor, provides plasma composition dependence on reactor operating parameter such…
Abstract Verglichen werden die kristallographischen Eigenschaften der Auride M 3 AuO und der Alkalimetallhalogenidoxide M 3 XO (M = K, Rb, Cs; × = Br, I). Rb 3 BrO, Rb 3 IO, Cs 3 BrO und Cs 3 IO werden erstmals dargestellt und strukturell charakterisiert: Rb 3 BrO (a = 5,465(1) Å) kristallisiert als kubischer anti‐Per…