Materials Literature
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Abstract The temperature dependence of 35 C1, 81 Br, and 127 I NQR frequencies and 1 Hspin-lattice relaxation times (T 1 ) for CH 3 NH 3 PbX 3 (X = Cl, Br, I) was measured through the successive phase transitions in these solids. The isotropic reorientation of the CH 3 NH 3 ions takes place in the higher-temperature p…
Abstract A mild acid attack of the Llano vermiculite produces porous materials suitable for use as cracking catalysts and/or catalysts supports. After HCl attack at 80°C (1 m ), the number of acid sites measured by the Hammett indicator method is ∼0·50/nm 2 , and the specific surfaces are 245 m 2 /g after calcination…
The effect of green density on both the densification rate and the creep rate was measured simultaneously during sintering by loading dilatometry. The experiments were performed on zinc oxide powder compacts with five different green densities covering a range of 0.39 to 0.73 of theoretical. The samples were heated at…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTExtractive crystallization of salts from concentrated aqueous solutionDavid A. Weingaertner, Scott Lynn, and Donald N. HansonCite this: Ind. Eng. Chem. Res. 1991, 30, 3, 490–501Publication Date (Print):March 1, 1991Publication History Published online1 May 2002Published inis…
High-technology electronic devices are based on highly specialized core materials that make their operation pos sible : semiconductors. Unfortunately, the range of mate rial properties that make high-technology devices work is extremely narrow, since the sheer number of useful semiconductors is small. Hence, a major c…
Polymer chains adsorbed on rough impenetrable surfaces have been investigated analytically and by simulations. The cases of physical and chemical roughness of surfaces are identified and their distinctive effects on the adsorption characteristics are studied. For the chemically rough surface the adsorption temperature…
ABSTRACT The apparent permeability constants for potassium sorbate and sorbic acid through an edible film composed of methylcellulose and palmitic acid (weight ratio 3:1) were evaluated as a function of water activity (a w ) and pH. For films with thickness 55–66 μm, potassium sorbate permeability increased from 2.3 ×…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTModulation of valence orbital levels of metalloporphyrins by .beta.-substitution: evidence from spectroscopic and electrochemical studies of 2-substituted metallo-5,10,15,20-tetraphenylporphyrinsRobert A. Binstead, Maxwell J. Crossley, and Noel S. HushCite this: Inorg. Chem.…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThermodynamic and kinetic studies of lanthanide complexes of 1,4,7,10,13-pentaazacyclopentadecane-N,N',N'',N''',N''''-pentaacetic acid and 1,4,7,10,13,16-hexaazacyclooctadecane-N,N',N'',N''',N'''',N'''''-hexaacetic acidMutsuo Kodama, Tohru Koike, Anung Budhi Mahatma, and Eii…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStable polyradicals with high-spin ground states. 1. Synthesis, separation, and magnetic characterization of the stereoisomers of 2,4,5,6-tetrachloro-.alpha.,.alpha.,.alpha.',.alpha.'-tetrakis(pentachlorophenyl)-m-xylylene biradicalJaume Veciana, Concepcio Rovira, Maria I. C…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHost-guest complexation. 55. Guest capture during shell closureJudi A. Bryant, Michael T. Blanda, Marco Vincenti, and Donald J. CramCite this: J. Am. Chem. Soc. 1991, 113, 6, 2167–2172Publication Date (Print):March 1, 1991Publication History Published online1 May 2002Publish…
The assembly of type I collagen molecules into native fibrils can be accomplished in vitro in solutions at physiological ionic strength and pH by raising the temperature above 30 degrees C. The thermal self-assembly reaction exhibits a distinct lag phase. This lag phase has been proposed to be evidence for a conformat…
We propose a model embedded-atom (many-body) potential and test it against an effective, density-independent, pairwise-additive potential in a variety of nonequilibrium molecular-dynamics simulations of plastic deformation under high stress. Even though both kinds of interactions have nearly the same equilibrium equat…
Abstract We hypothesize that the decomposition of organic debris derived from plants, planktonic animals, and algae by sulfate-reducing bacteria, and specifically by the enzymatic degradation of protein, is vital to organogenic dolomitization. The role of this degradation is to increase both alkalinity and pH of the p…
We developed engineering models that predict forces and penetration depth for long, rigid rods with spherical noses and rate-independent, strain-hardening targets. The spherical cavity expansion approximation simplified the target analysis, so we obtained closed-form penetration equations that showed the geometric and…
Three techniques were evaluated as soil P tests for western Canadian soils: anion‐exchange membrane (AEM), water, and bicarbonate extraction. The AEM, water, and bicarbonate‐extractable total P represented novel approaches to compare to the widely used bicarbonate‐extractable inorganic P (traditional Olsen) soil test.…
Possible phases in a nematic liquid crystal confined to a spherical submicrometer droplet embedded in a solid polymer are analyzed in terms of a Landau--de Gennes theory. For a droplet with a radial structure we show that the strength of the nematic-polymer interfacial interaction affects the nematic-paranematic (part…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis of nonionic gadolinium chelates useful as contrast agents for magnetic resonance imaging: 1,4,7-tris(carboxymethyl)-10-substituted-1,4,7,10-tetraazacyclododecanes and their corresponding gadolinium chelatesD. D. Dischino, E. J. Delaney, J. E. Emswiler, G. T. Gaugha…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNuclear magnetic resonance studies on electrochemically prepared poly(3-dodecylthiophene)Masaaki Sato and Hisayuki MoriiCite this: Macromolecules 1991, 24, 5, 1196–1200Publication Date (Print):March 1, 1991Publication History Published online1 May 2002Published inissue 1 Mar…
A series of segmented polyurethanes (SPUs) containing various polyol soft segments was prepared and their resistance to oxidative degradation was investigated after aging in AgNO3 solution. The SPU with the polyether soft segment showed a large reduction in mechanical strength after exposure to the oxidative environme…