Materials Literature
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ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTViscoeleastic properties of solutions of star-branched polystyreneKunihiro Osaki, Eiichi Takatori, Michio Kurata, Hiroshi Watanabe, Hirotsugu Yoshida, and Tadao KotakaCite this: Macromolecules 1990, 23, 20, 4392–4396Publication Date (Print):October 1, 1990Publication History…
A Brookfield RVTD mixer viscometer was used to gelatinize 5.5, 6.4, and 7.3% (d.b.) native corn starch solutions, and a 6% bean starch solution. Torque, the dependent variable, was used to estimate parameters in a generalized viscosity model. The independent variables were impeller speed, temperature (50–95°C), concen…
Impact ionization rates for electrons and holes in (100) A10.48In0.52As were determined from photo multiplication measurements using AIInAs / FaInAsp +-i-ndiodes grown by metal-organic vapor phase epitaxy (MOVPE). The impact ionization rate ratio (prop; / beta;) was derived as being 2.0 ~ 3.5 over the electric field r…
Alloy sheets of Ni–49·2at% Ti were cold rolled at room temperature. The microstructure of a 60% reduced sample showed the formation of amorphous bands within the finely twinned crystalline matrix. Sample fracture was observed for reductions of more than 65%. The fracture surface extended straight and inclined 30° to 5…
Abstract Thermoluminescence spectra have been recorded for crystals of pure KMgF3, KMgF3:Pb2+ and KMgF3:Eu3+, with the aim of identifying new phosphors for radiation dosimetry. Glow peaks, due to thermal activation of colour centres formed by ß or ? irradiation, were measured in both pure and doped materials. Typical…
The domain structure self-assembled under a steady Couette flow was investigated on a semidilute solution of polymer mixture (polymer A + polymer B + solvent) at a composition near the critical one by use of the in situ light scattering method. This method permits a quantitative analysis of the scattering profile I(qy…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTriangulanes: stereoisomerism and general method of synthesisN. S. Zefirov, S. I. Kozhushkov, T. S. Kuznetsova, O. V. Kokoreva, K. A. Lukin, B. I. Ugrak, and S. S. TratchCite this: J. Am. Chem. Soc. 1990, 112, 21, 7702–7707Publication Date (Print):October 1, 1990Publication…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDimerization of metalloporphyrin .pi. cation radicals. Characterization of two novel dimers: [Zn(OEP.cntdot.)(OH2)]2(ClO4)2 and [Ni(OEP)]2(ClO4)2Hungsun Song, Robert D. Orosz, Christopher A. Reed, and W. Robert ScheidtCite this: Inorg. Chem. 1990, 29, 21, 4274–4282Publicatio…
The rumen entodiniomorphid ciliate protozoon Polyplastron multivesiculatum was shown, by biochemical and electron microscopic techniques, to possess hydrogenosomes. After differential centrifugation of whole cell homogenates the hydrogenosomal marker enzymes pyruvate:ferredoxin oxidoreductase and hydrogenase were reco…
A computer model of blood plasma which has allowed the effect of Gd(III) contrast agents to be simulated has been developed. Initial binding of Gd(III) is to transferrin. At high concentration the metal ion binds to citrate and salicylate. At a concentrate of 10(-3) M, GdCl3 is predicted to effect a redistribution of…
A field-emission-gun scanning electron microscope (FEG SEM) has been fitted with a back-scattered electron detector in order to image dislocations by the electron channelling contrast mechanism. By using an efficient detector, optimizing its orientation with respect to the specimen and the incident beam, and applying…
Abstract By using optical microscopy, small‐angle X‐ray scattering and differential scanning calorimetry, the melting behaviour and the structural parameters of poly(ethylene oxide)/poly(methyl methacrylate) (PEO/PMMA) blends are determined. The equation that relates the observed melting temperature, T m ′, to the lam…
Computer simulations of cellular pattern growth (domain growth) have been carried out for two- and three-dimensional vertex model. Geometrical properties beyond the edge-number distribution have been studied for a two-dimensional cellular pattern in the scaling regime. The method of simulation is shown in three dimens…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSpin transition in iron Fe(py)2L(NCS)2 complexes where py = pyridine and L = 2,2'-bipyrimidine (bpym) and 1,10-phenanthroline (phen): magnetic, calorimetric, and Moessbauer-effect investigation. Crystal structure of [Fe(py)2bpym(NCS)2].0.25pyRenee Claude, Jose Antonio Real,…
Colloidal polyaniline has been prepared in acidic aqueous media by a modified chemical polymerization of aniline in the presence of a tailor-made polymeric surfactant. The surfactant which acts as a steric stabilizer used in this study is derivatized poly(vinyl alcohol-co-vinyl acetate). This surfactant contains penda…
Abstract We have been studying crystallization and melting behavior of high performance semicrystalline polymers to increase our understanding of the effects of processing on microstructure. Questions on development of morphology center around whether single or dual populations of crystals exist after melt processing,…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthetic nickel-iron NiFe3Q4 cubane-type clusters (S = 3/2) by reductive rearrangement of linear [Fe3Q4(SEt)4]3- (Q = sulfur, selenium)Stefano Ciurli, Shi Bao Yu, R. H. Holm, K. K. P. Srivastava, and E. MunckCite this: J. Am. Chem. Soc. 1990, 112, 22, 8169–8171Publication D…
The host-vector system for an extreme thermophile, Thermus thermophilus HB27, was developed. The host strain has a mutation in tryptophan synthetase gene (trpB), and the mutation was determined to be a missense mutation by DNA sequence analysis. A Thermus-E. coli shuttle vector pYK109 was constructed. pYK109 consists…
Abstract To determine the mechanisms of the electron-hole processes in a-Al2O3:C crystals, characteristics of their thermo- and photo-stimulated exoelectron emission (TSEE, PSEE) and luminescence have been studied. It is shown that the emission of F+ centres takes place with the temperature shift relative to the emiss…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAn unprecedented, bridged dihydrogen complex of a cofacial metallodiporphyrin and its relevance to the bimolecular reductive elimination of hydrogenJames P. Collman, James E. Hutchison, Paul S. Wagenknecht, Nathan S. Lewis, Michel Angel Lopez, and Roger GuilardCite this: J.…