Materials Literature
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ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPorphyrin sponges. Inversion disorder and inversion twinning in lattice clathrates based on five-coordinate metallotetraarylporphyrin complexesMarianne P. Byrn and Charles E. StrouseCite this: J. Am. Chem. Soc. 1991, 113, 7, 2501–2508Publication Date (Print):March 1, 1991Pub…
Klebsiella pneumoniae catabolizes both 4-hydroxyphenylacetic acid and 3-hydroxyphenylacetic acid via meta-cleavage of 3,4-dihydroxyphenylacetic acid, ultimately yielding pyruvate and succinate. The organism can synthesize two hydroxylases catalysing 3,4-dihydroxyphenylacetic acid formation, which differ in substrate s…
Abstract Cationic ring‐opening polymerization of e‐caprolactone using triethyloxonium hexafluorophosphate initiator in the presence of alcohol to produce low molecular weight polyester glycol was examined. The polymerization proceeded by an activated monomer mechanism; thus the polymer molecular weight increased direc…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTComplexation, luminescence, and energy transfer of cerium(3+) with a series of multidentate aminophosphonic acids in aqueous solutionSteven T. Frey and William D. Horrocks Jr.Cite this: Inorg. Chem. 1991, 30, 5, 1073–1079Publication Date (Print):March 1, 1991Publication Hist…
Abstract A review of relevant microscopic processes, both chemical and physical, which occur during suspension, bulk and emulsion polymerization (both before and after pressure drop) is given. The state of the art of kinetic modelling of monomer consumption rate, reactor pressure, molecular weight and short and long c…
We present a derivation of the microscopic expressions for the elastic constants of nematic liquid crystals within the density functional formalism. We recover the expressions of Poniewierski and Stecki for molecules with three planes of symmetry, but our general expression includes the effects of the relaxation in th…
Continuous stoichiometric silicon nitride fiber was produced by the pyrolysis of perhydropolysilazane. This high‐purity silicon nitride fiber is colorless and has high strength, modulus of elasticity, and thermal stability which are properties suitable for reinforcing plastics, metals, glasses, and even ceramics. The…
As-polymerized poly(L-lactide) test rods were sterilized by seven different specially designed computer-operated autoclaving programs. As a control, common hospital sterilization was performed. In all cases, the molecular weight decreased after sterilization. A short time high-temperature sterilization led to less mol…
At high temperatures in clean oxidizing environments, SiC forms a very protective SiO 2 film, but, in environments containing low levels of gaseous alkali salt contaminants or where condensed salts may deposit on the surface, the resistance of the film is significantly reduced. Oxidation kinetics of SiC were measured…
Albumin and fibrinogen were competitively adsorbed onto dimethyldichlorosilane-coated glass (DDS-glass) and platelet activation was examined as a function of the surface fibrinogen concentration. The weight ratio of albumin to fibrinogen in the adsorption solution was varied from 10 to 700. Platelet activation was qua…
We compared the relative toxicities of standard concentrations of two magnetic resonance imaging (MRI) contrast agents, ionic gadolinium diethylenetriaminepentacetic acid (DTPA) and low-osmolar gadolinium-1, 4, 7 tris (carboxymethyl)-10-(2'-hydroxypropyl)-1, 4, 7, 10 tetra-azacyclododecane (HP-DO3A) with that of the c…
The photoredox behavior of various iron meso-tetraarylporphyrins in ethanol-containing solvents is examined. The reduction of Fe(III) to Fe(II) is observed in every case under irradiation with light of 350-450 nm. The electron-drawing or -repelling power of the meso-aryl substituents are found to have a scarce influen…
The aqueous gel forming properties of three series of block copolymer surfactants, poloxamers, poloxamines, and Butronic® polyols, are briefly reviewed and compared. The differences in their gel formation properties are explained. Aqueous gel formation of these polymers is attributed to the aggregation of extended lin…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAsymmetric synthesis of the corynantheine alkaloids via an intramolecular Blaise reaction. (-)-Corynantheidol and (-)-dihydrocorynantheolRichard L. Beard and A. I. MeyersCite this: J. Org. Chem. 1991, 56, 6, 2091–2096Publication Date (Print):March 1, 1991Publication History…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA study of colloidal crystal morphology and orientation via polarizing microscopyYiannis Monovoukas and Alice P. GastCite this: Langmuir 1991, 7, 3, 460–468Publication Date (Print):March 1, 1991Publication History Published online1 May 2002Published inissue 1 March 1991https…
Electrochemical impedance spectroscopy measurements were conducted on rotating disk specimens of pure copper and commercial 90‐10 and 70‐30 copper‐nickel alloys over a 28 day period while immersed in an aerated aqueous 3.4% NaCl solution, after vapor deposition of a Pd layer and finally after stripping the detachable…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTConvenient syntheses of carboxylic acid functionalized fluoropolymer surfacesMolly S. Shoichet and Thomas J. McCarthyCite this: Macromolecules 1991, 24, 5, 982–986Publication Date (Print):March 1, 1991Publication History Published online1 May 2002Published inissue 1 March 19…
The softening of phonon modes is sensitive to stress. Both the internal tensile stress formed by Ti11Ni14 precipitates in Ni-rich Ti-Ni alloy and the internal stress introduced by thermal cycling in equiatomic Ti-Ni alloy have strong effects on the softening of phonon modes, especially on phonons with <111> polarizati…
The effects of exposures to high‐temperature gaseous atmospheres on the strength of Nicalon SiC fibers were investigated. The exposure conditions were as follows: (1) H 2 with various P H2O for 10 h at 1000° and 1200°C, and (2) air for 2 to 100 h at 800° to 1400°C. Individual fibers were tested in tension following ea…
Elastic modulus E 1 of crystalline regions in the direction parallel to the chain axis has been measured for various kinds of polyethylene (PE) with different microstructures, such as ultrahigh-modulus PE, linear low-density PE, high-pressure-crystallized PE, and a heat-drawn PE whose crystallite size exceeds its long…