Materials Literature
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Abstract Pyrolysis capillary gas chromatography (Py-GC) was used to compare thirty black polyvinylchloride (PVC) tapes. A 0.5-mm square of tape (about 25 μg) was found to be an adequate sample size. Tests of within-roll homogeneity showed sufficiently consistent pyrogram patterns throughout to allow correct matches to…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSolid-state organometallic chemistry of molecular metal oxide clusters: carbon-hydrogen activation by an iridium polyoxometalateA. R. Siedle, R. A. Newmark, K. A. Brown-Wensley, R. P. Skarjune, L. C. Haddad, K. O. Hodgson, and A. L. RoeCite this: Organometallics 1988, 7, 9,…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNitrogen atom activation: the influence of porphyrin ring structure on the kinetics of the reaction of trifluoroacetic anhydride with nitrido manganese(V) porphyrinsLawrence A. Bottomley and Frank L. NeelyCite this: J. Am. Chem. Soc. 1988, 110, 20, 6748–6752Publication Date…
Simultaneous grain growth of the lime (CaO) and periclase (MgO) phases was studied in a synthetic, hydroxide‐derived doloma over the temperature range 1400° to 1700°C. The grain growth kinetic exponents were 5 and 6 and the activation energies 333±45 and 437±47 kJ/mol for the CaO and MgO phases, respectively. The larg…
Abstract The incorporation of a range of iron‐containing inorganic and organometallic compounds into a semi‐rigid PVC formulation has been investigated. Limiting Oxygen Index and Smoke Density data were obtained across a wide range of formulations and the effects of the compounds on flammability and smoke generation a…
Abstract The crystal structure of [AsPh 4 ] 2 [Pb(N 3 ) 6 ] 2- has been determined by X-ray diffraction. The structure of [Pb(N 3 ) 6 ] 2- (C i symmetry) is analogous to that of [Sn(N 3 ) 6 ] 2- with covalent Pb-N bonds (222-226 pm) and angles Pb-N-N between 115 and 121°. Irridiation (daylight) of [AsPh 4 ] 2 [Pb(N 3…
A systematic procedure using the effective index method and impedance matching has recently been developed Appl. Opt. 26, 3123 (1987)] for the design of antireflection high-spatial-frequency rectangulargroove gratings on lossy materials including high conductivity metals. The design procedure in turn can be used as a…
Whereas titanium is a getter material mainly suitable for the long-term storage of tritium, zirconium cobalt alloy can also be employed for the interim storage and transport of this gas. Activated zirconium cobalt alloy reacts within minutes with hydrogen at room temperature. At the composition of ZrCoH0.8 the dissoci…
The application of ferroelectric liquid-crystal devices to optical processing is discussed. Our current activity in silicon photoaddressed ferroelectric liquid-crystal spatial light modulators is reported.
Abstract A fully-predictive mathematical model has been developed for the peroxide promoted degradation of polypropylene in a plasticating single-screw extruder. The model is based on a free radical kinetic mechanism for the degradation reaction and on conventional plasticating extrusion theory. Solids conveying, melt…
Endeavoring to develop a method to biosynthesize proteins substituted with nonprotein amino acids, we attempted the incorporation of L-2-aminohexanoic acid (Ahx) into human epidermal growth factor (hEGF). Escherichia coli YK537 strain harboring plasmid pTA1522, which has the phoA promoter-phoA signal peptide-hEGF gene…
A study was undertaken to define better the concept of the statistical grain. A cube having edges of 52·1 mm was cut from a slowly cooled β-brass ingot which had equiaxed grains. The distributions of sizes and shapes of grain sections on the faces of the cube were determined. The grains were then separated in a soluti…
Abstract— The rate constant k 5 / > for physical quenching of singlet oxygen O 2 (δ 1 ;) by the sensitizer in dye‐sensitized photooxygenations is determined in the case of chlorophylls a and b (7.3 times 10 8 , 4.2 times 10 8 M ‐1 s ‐1 respectively), pheophytins a and b (7.4 times 10 7 , 3.0 times 10 7 M ‐1 s _1 re…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe preparation and structure of a dinuclear .eta.2-H2 complex (P-N)(.eta.2-H2)Ru(.mu.-Cl)2(.mu.-H)Ru(H)(PPh3)2, P-N = Fe[.eta.-C5H3(CHMeNMe2){P(iso-Pr)2}-1,2](.eta.-C5H5)Cashman. Hampton, William R. Cullen, Brian R. James, and Jean Pierre. CharlandCite this: J. Am. Chem. So…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTUmuhengerin, a New Antimicrobially Active Flavonoid from Lantana trifoliaP. C. Rwangabo, M. Claeys, L. Pieters, J. Corthout, D. A. Vanden Berghe, and A. J. VlietinckCite this: J. Nat. Prod. 1988, 51, 5, 966–968Publication Date (Print):September 1, 1988Publication History Pub…
X-ray diffraction measurements have been made on the nematic phase of T15 (4-cyano-4′-n-pentyl-p-terphenyl), as well as on the nematic and smectic A phases of RNO2 [4′-nitrophenyl-4-(4′-n-hexyloxy-benzoyloxy)-cinnamate]. The x-ray equipment used allows comparably high resolution measurements of liquid crystals. The in…
Abstract We have reexamined the parallel Avrami model recently proposed by Velisaris and Seferis (1) to describe the non‐Isothermal crystallization of poly(etheretherketone), PEEK. We show that, based on considerations of morphology development, the crystallization process with the larger Avrami exponent has the highe…
Details are given of a new organic electro-optic crystal, 3-(1,1-dicyanoethenyl)-1-phenyl-4,5-dihydro-1H-pyrazole, having a reduced half-wave voltage of 370 V (approximately 8 times lower than lithium niobate). The molecular design, synthesis, and molecular characterization of this compound are outlined and a descript…
Analysis of the pH dependence of the kinetic parameters and competitive inhibitor Ki values for tryptophan indole-lyase suggests two enzymic groups must be unprotonated in order to facilitate binding and catalysis of tryptophan. The V/K for tryptophan and the pKi for oxindolyl-L-alanine, a putative transition state an…
Experiments were conducted on samples of depleted uranium and on intermetallic compounds of zirconium-cobalt and lanthanum-nickel-aluminide to evaluate the pyrophoricity of the activated materials and their hydrides and deuterides on exposure to air. None of the materials spontaneously ignited when exposed to room tem…