Materials Literature
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Abstract In this contribution, the X‐ray diffraction (XRD) pattern of a highly oriented sample of syndiotactic polystyrene in the mesomorphic form, collected by an automatic diffractometer, is presented, thus providing quantitative and more complete information relative to the diffracted intensity. The structural chan…
TiCl3-induced coupling of meso-forrnylporphyrins provides cofacial porphyrin dimers such as 1 (M Cu, Ni) with bridging cis-CHCH units. These compounds show strong interactions between the porphyrin rings; in the case of M Ni, the dimer can be easily transformed into the corresponding trans isomer. Similar reactio…
The effects of both polymer hydrophobicity and addition of stabilizers on the release and integrity of polymer-encapsulated proteins were studied. By using very hydrophobic poly[1,3-bis(p-carboxyhydroxy)hexane anhydride] with sucrose as an excipient, both recombinant bovine somatotropin and zinc insulin were released…
Lead magnesium niobate (Pb(Mg 1/3 Nb 2/3 )O 3 , PMN) was prepared by a molten salt synthesis method. Powder characteristics were greatly influenced by the processing parameters, such as amount of salt, species of salt, and the presence of excess PbO. Grown in sulfate salts, PMN crystallites showed faceted morphology w…
A dense and isotropic Si 3 N 4 composite body containing 25 vol% of α‐SiC platelets, with average particle size of 24μm and aspect ratio of 8 to 10, was fabricated by hot isostatic pressing without any addition of sintering aids. In this composite, desirable properties for structural ceramics to be used in long‐term h…
Abstract Dendrimers with bulky repeating units containing up to 43 benzene rings (in 9 ) have been obtained by using a repetitive divergent synthetic strategy (three generations). The new functional dendrimer 13 containing six azobenzene units at the periphery was synthesized allowing a reversible switching of the sha…
Frequency dependent representations of eddy currents in laminated cores of power transformers are developed. One representation is based on a continued fraction expansion for the frequency dependent magnetizing impedance while the other is based on a discretization of flux distribution within the lamination. Both mode…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEnantioselective epoxidation of unfunctionalized olefins catalyzed by threitol-strapped manganese porphyrinsJames P. Collman, Virgil J. Lee, Xumu Zhang, James A. Ibers, and John I. BraumanCite this: J. Am. Chem. Soc. 1993, 115, 9, 3834–3835Publication Date (Print):May 1, 199…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and processing of heterocyclic polymers as electronic, optoelectronic, and nonlinear optical materials. 3. New conjugated polyquinolines with electron-donor or -acceptor side groupsAshwini K. Agrawal and Samson A. JenekheCite this: Chem. Mater. 1993, 5, 5, 633–640P…
Abstract Gypsum (CaSO 4 ·2H 2 O) is used in agriculture both as a source of calcium (Ca 2+ ) and sulfate (SO 2− 4 ) and as an amendment to improve soil structure. We examined the effect of Ca 2+ on the adsorption of SO 2− 4 in variable‐charge soils. Sulfate adsorption measurements from batch and column experiments sho…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEffect of component oxide interaction on the adsorption properties of mixed oxidesXiaoguang Meng and Raymond D. LettermanCite this: Environ. Sci. Technol. 1993, 27, 5, 970–975Publication Date (Print):May 1, 1993Publication History Published online1 May 2002Published inissue…
Two new sensitizers are introduced for a potential use in photodynamic therapy: Zn(2+)- and MG(2+)-tetrabenzoporphyrin (ZnTBP and MgTBP). A comparative study of the quantum yields of singlet oxygen generation (phi delta) of hematoporphyrin derivative (HpD), Photofrin II (PF-II), Zn(2+)-phthalocyanine tetrahydroxyl [Zn…
The sensitivity of the transfer function to finite-wordlength-effect errors in the implementation of the coefficients of both shift operator and delta operator parameterizations is analyzed. The relationships between optimal realization sets in shift and delta operator are established. It is shown that the optimal rea…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDistorted manganese cubane [Mn4O3Cl]6+ complexes with arenecarboxylate ligation: crystallographic, magnetochemical, and spectroscopic characterizationMichael W. Wemple, Hui Lien Tsai, Kirsten Folting, David N. Hendrickson, and George ChristouCite this: Inorg. Chem. 1993, 32,…
The propagation of indentation radial cracks in soda—lime silicate glass is measured as a function of time after indentation. Rapid lift‐off of the indenter from the specimen surface causes a step‐function perturbation in the radial crack mechanical energy release rate, thus providing access to a large range of observ…
The electro-optic properties of 2-cyclooctylamino-5-nitropyridine and 2-(N-prolinol)-5-nitropyridine single crystals have been evaluated. The dependence of the electro-optic coefficients on the optical wavelength and the frequency of the applied electric field was determined. Enhancements of these coefficients near ac…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTObservation of a noncovalent ribonuclease S-protein/S-peptide complex by electrospray ionization mass spectrometryRachel R. Ogorzalek Loo, David R. Goodlett, Richard D. Smith, and Joseph A. LooCite this: J. Am. Chem. Soc. 1993, 115, 10, 4391–4392Publication Date (Print):May…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInteraction of tetradecyltrimethylammonium bromide with poly(acrylic acid) and poly(methacrylic acid). Effect of charge densityJ. J. Kiefer, P. Somasundaran, and K. P. AnanthapadmanabhanCite this: Langmuir 1993, 9, 5, 1187–1192Publication Date (Print):May 1, 1993Publication…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDesign and evaluation of an echelle grating optical system for ICP-OESThomas W. Barnard, Michael I. Crockett, Juan C. Ivaldi, and Peter L. LundbergCite this: Anal. Chem. 1993, 65, 9, 1225–1230Publication Date (Print):May 1, 1993Publication History Published online1 May 2002P…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThiophene oligomers as polythiophene models. 2. Electrochemistry and in situ ESR of end-capped oligothienyls in the solid state. Evidence for .pi.-dimerization of hexameric polarons in polythiopheneGianni Zotti, Gilberto Schiavon, Anna Berlin, and Giorgio PaganiCite this: Ch…