Materials Literature
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From the rhizomes of HYPOXIS OBTUSA two monoglucosides having the same aglycone as hypoxoside, 1-(3',4'- dihydroxyphenyl)-5-(3'',4''-dihydroxyphenyl)-1-pen-ten-4-yne, have been obtained. By methylation followed by hydrogenation they have been transformed into the same compound, 1-(3'-methoxy-4'- O-beta- D-glucopyranos…
Abstract The Raman spectrum of sulphonated copper phthalocyanine on a silver electrode surface is reported for four excitation wavelengths in the Q ‐band region at voltages between +0.6 and −0.6 V (vs SCE). SERS activity is observed and the bonding and orientation of the surface species are voltage dependent and are i…
Abstract Polyamic acid films interact as ion‐exchange substrates for dilute aqueous cation solutions. Three conditions were evaluated: basic solutions which form soluble amic acid salts and dissolve the film, weakly acidic solutions which encourage classical weak acid cation exchange, and strongly acidic solutions whi…
Abstract The mathematical relationships are developed which are pertinent to the quantitative analysis of powder mixtures for the case of diffraction from the surface of a flat powder specimen. These formulas relate the diffracted intensity to the absorptive properties of the sample. Three important cases are treated:…
We report on the response of three scientific charge-coupled devices (CCD), the RCA SID501, the Tektronix TK512M, and the Texas Instruments 4849, to direct electron bombardment. A scanning electron microscope is used to provide a temporally gated, focused electron source of precise energy and current. Both the detecti…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSkeletally stabilized triphosphazanes: new classes of linear phosphazanesJoseph M. Barendt, Elizabeth G. Bent, R. Curtis Haltiwanger, and Arlan D. NormanCite this: Inorg. Chem. 1989, 28, 12, 2334–2339Publication Date (Print):June 1, 1989Publication History Published online1…
CuMg 1,425 Cr 0,611 Si 1,964 O 6 cristallise dans P2 1 /c avec affinement jusqu'a 0,032, la structure etant similaire a celle du mineral clinoenstatite
Abstract In the present work blends between poly(methylmethacrylate) (PMMA) and poly(ethylene‐co‐vinylacetate) (EVA) or its derivative EVA‐g‐succinic anhydride (EVA‐g‐SA) have been investigated by linear elastic fracture mechanics (LEFM) with Charpy impact tests and by scanning electron microscopy (SEM). Blends prepar…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSupersaturation and crystallization kinetics of potassium chlorideRuying Qian, Xianshen Fang, and Zhikeng WangCite this: Ind. Eng. Chem. Res. 1989, 28, 6, 844–850Publication Date (Print):June 1, 1989Publication History Published online1 May 2002Published inissue 1 June 1989h…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe unusually slow hydrolysis rate of silyl methyl ketals in benzoquinone systems. The question of siloxy stabilization of an adjacent positive charge and stereoelectronic effects on ketal hydrolysisAlan J. Stern and John S. SwentonCite this: J. Org. Chem. 1989, 54, 12, 2953…
Cingulum and valve morphology of the marine epizoic diatom Falcula hyalina Takano, collected from Choctawhatchee Bay, northeastern Gulf of Mexico, were studied with scanning electron microscopy. The cingulum is composed of four incomplete ligulate bands. The apical pore fields are interpreted as ocellulimbi. Its taxon…
Phase development as a function of hot‐pressing temperature was studied in alkoxide‐derived titanate‐based ceramics doped with a 10 wt% loading of a sodium‐rich (NAR) and a sodiumpoor (NAP) simulated high‐level waste. Pyrochlore was found to be the most abundant phase in both calcine powders. A pseudobrookite phase ex…
Abstract Samples of Narmco Rigidite 5208/WC3000 carbon‐epoxy prepreg were exposed to ambient temperature (22°C) and 50% relative humidity for different periods up to 66 days. They were analyzed in depth using various techniques to determine the extent of the chemical changes occurring. The physicochemical techniques u…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSolid-state chemistry of molecular metal oxide clusters. Reactions of microporous dihydridobis(triphenylphosphine)iridium-tungsten complex [(Ph3P)2IrH2]3PW12O40 with small organic moleculesA. R. Siedle and R. A. NewmarkCite this: Organometallics 1989, 8, 6, 1442–1450Publicat…
Cristallisation dans P6 3 /mmc avec affinement jusqu'a 0,044. La structure consiste en une alternance de couches de structure spinelle ou de structure perovskite
Abstract The fundamental aspects of PVC degradation and stabilization are discussed. The primary process of thermal degradation (initiation, zip‐elimination of HCl and simultaneous formation of polyene sequences, and termination of unzipping) is reevaluated in the light of results obtained with PVCs containing increas…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTChemical kinetics and reaction mechanism of thermal decomposition of aluminum hydroxide and magnesium hydroxide at high temperature (973-1123 K)Ienwhei Chen, Shuh Kwei Hwang, and Shyan ChenCite this: Ind. Eng. Chem. Res. 1989, 28, 6, 738–742Publication Date (Print):June 1, 1…
The absolute efficiency of Gd 2 O 2 S:Tb screens under fluoroscopic conditions was studied and found to vary between 0.5 and 9.0*10 -5 W m -2 mR -1 s depending on the X-ray tube voltage and on the screen's weight. Theoretical calculations based on the uniform screen model gave results in close agreement with experimen…
We have conducted wearer trials demonstrating that human subjects can perceive the heat of sorption of water vapor by wool garments in typical winter conditions. We found that this heat of sorption causes wearers to rate wool garments as warmer under certain conditions than materials with little or no heat of sorption…
Abstract This paper reviews research since 1980 on the equilibria and kinetics of transport of small organic molecules in rigid and plasticized PVC. The forms of both the solubility isotherms and the sorption kinetics are shown to change as the PVC/penetrant system undergoes a glass‐rubber transition with an increase…