Materials Literature
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The structure of 4-aminopyridine hemiperchlorate, C5H6N2⋅1/2HClO4, has been determined from three-dimensional neutron diffraction data. The crystals are monoclinic, space group P21/n, with cell dimensions a=11.224 (7) Å, b=9.325 (6) Å, c=16.631 (9) Å, β=102.72 (3) ° and Z=4. The structure was refined to an R(F02) =0.1…
It will be demonstrated that the determination of pore structures of chemically modified silica gels is possible by simple chromatographic measurements. Silica gels with different mean pore diameters (60–300Å) have been modified by bonding silanes to their surface. Silanes with different alkyl chain lengths and differ…
Abstract Seven kaolins from Georgia (southeastern U.S.A.), ranging from high to low commercial grade, were characterized by X-ray powder diffraction and chemical techniques to establish that the variation in quality was caused by impurities. The Ca and Cs cation-exchange capacities (CEC) varied from 2.67 to 8.17 and f…
Following a very brief historical review, x-ray diffraction by nematic and smectic liquid crystals is critically examined in terms of the data available and the structural models and molecular theories that have been proposed to explain it. Studiesof TBBA are used to illustrate some of the principal mesophases that ha…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEvaluation of a New Zeolitic Catalyst for NOx Reduction with NH3Joseph R. Klovsky, Pramod B. Koradia, and Charles T. LimCite this: Ind. Eng. Chem. Prod. Res. Dev. 1980, 19, 2, 218–225Publication Date (Print):June 1, 1980Publication History Published online1 May 2002Published…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDistances of electron transfer to and from metalloprotein redox sites in reactions with inorganic complexesA. Grant Mauk, Robert A. Scott, and Harry B. GrayCite this: J. Am. Chem. Soc. 1980, 102, 13, 4360–4363Publication Date (Print):June 1, 1980Publication History Published…
Abstract Direct pyrolysis in the mass spectrometer (MS) yielded unequivocal evidence regarding the mechanism of thermal decomposition of N ‐monosubstituted and N ‐disubstituted polyurethanes. It was ascertained that direct pyrolysis in the MS detects the primary thermal fragments that originate from polyurethane pyrol…
Abstract Botryoidal and fan-shaped masses of polycrystalline calcite pseudospar from Permian biohermal limestones in New Mexico and Texas are interpreted as replacements of radially-divergent, acicular marine cements. The mosaic consists of composites of and individual ray-crystals, with included relicts of square-tip…
Abstract Annealing of poly(ethylene terephthalate) samples crystallized under isothermal conditions above the crystallization temperature has a marked influence on their morphology and results in increased thermal stability of the crystalline structure as indicated by the melting point increase of the samples. The mor…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTReactions of superoxide with iron porphyrins in aprotic solvents. A high spin ferric porphyrin peroxo complexElizabeth McCandlish, Andrew R. Miksztal, Mario Nappa, Alice Q. Sprenger, Joan S. Valentine, John D. Stong, and Thomas G. SpiroCite this: J. Am. Chem. Soc. 1980, 102,…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMicroemulsions, micelles, and vesicles as media for membrane mimetic photochemistryJanos H. FendlerCite this: J. Phys. Chem. 1980, 84, 12, 1485–1491Publication Date (Print):June 1, 1980Publication History Published online1 May 2002Published inissue 1 June 1980https://pubs.ac…
Abstract A detailed description of the morphology and the complex melting behavior of poly(ethylene terephthalate) crystallized isothermally in the range 100–245°C is presented. Double or single melting endotherms can deliberately be obtained by varying the heating rate in the differential scanning calorimeter (DSC).…
A recent theory of two-dimensional melting is applied to freely suspended liquid-crystal films with a tilt degree of freedom. As many as seven distinct phases are possible, including those we identify with smectic-$A$, -$B$, -$C$, and -$H$ liquid crystals. Some of these phases may survive when stacked to form bulk sme…
The kaolin minerals in the Amazon upland soils vary ranging from the well-crystallized triclinic/b-axis disordered kaolinite intermediate in a red yellow latosol and a red yellow podzolic soil to the disordered kaolinite/halloysite (7 Å) intermediate in a “Terra Roxa Estruturada” soil and a reddish brunizem. The parti…
Uranium aluminide powder production, fuel plate fabrication development, and irradiation performance of more than 1700 fuel elements during 10 yr of operational service at Idaho National Engineering Laboratory are discussed. The UAlx dispersion fuel system has performed well in extended service in the high flux test r…
A theoretical treatment is presented for the determination of the screw sense of a cholesteric substance in a Grandjean-Cano-wedge by observing the sample in a polarizing microscope. For comparison some experimental measurements are given
The controversial phase transitions in barium and bismuth were studied with a manganin coil sensor. The transition in barium proposed at 80 kbars by Bastide etal. was confirmed at 95 kbars. For bismuth, the transition reported first by Bridgman around 45 kbars was confirmed at 40 kbars, but that around 65 kbars could…
Abstract Lamellar single crystals of cellulose were obtained from dilute solutions of low‐DP cellulose triacetate, by deacetylation followed by precipitation. At temperatures between 150 and 160°C, pure cellulose IV II crystals were obtained whereas at temperatures between 90 and 150°C, hybrid crystals, having cellulo…
Observations of cathodoluminescence in ZnS single crystals using scanning transmission electron microscopy exhibit a dependence on crystal orientation indicating that about 20% of the signal originates in localized excitations. This figure can be explained in terms of energy transfer to valence excitations from energe…
Stress enhancement due to the migration of charges can be a critical factor in the design of solid insulation for high voltage DC systems. The effect of bulk currents on surface and internal charge accumulation is discussed; and equations are formulated which predict steady-state conditions in arbitrary configurations…