Materials Literature
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Benzylation of benzo[b]thiophene (1) with benzyl chloride catalyzed by metal-doped K-10 montmoril-lonite clays is described. Whereas ZnQ2 dissolved in either nitromethane or nitrobenzene solution promoted benzylation of (1) only very slowly and resulted in a mixture of mono- and poly-substituted products, ZnCl2-modifi…
Abstract The electrochemical behavior and surface chemistry of sputter‐deposited non‐equilibrium stainless Al–Ta alloys have been investigated. These alloys exhibit enhanced passivity over a pH range of 2–12 even though the passive film chemistry varies considerably over this range. This enhanced passivity can be expl…
Abstract Porphyrin oligomers (Pn, n = 2, 3, 4, 5) were prepared by the nucleophilic substitution of amino porphyrin monomers to cyanuric chloride. In this method, two different porphyrins can be joined stepwise to 1,3,5-triazine ring in one-pot by choosing appropriate reaction temperatures. The reaction proceeded unde…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTheoretical Prediction of the Optical Waveguiding Properties of Self-Assembled Block Copolymer FilmsJ. T. Chen, E. L. Thomas, C. G. Zimba, and J. F. RaboltCite this: Macromolecules 1995, 28, 17, 5811–5818Publication Date (Print):August 1, 1995Publication History Published on…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTParadigms and Paradoxes in Modeling Adsorption and Chromatographic SeparationsDaniel TondeurCite this: Ind. Eng. Chem. Res. 1995, 34, 8, 2782–2788Publication Date (Print):August 1, 1995Publication History Published online1 May 2002Published inissue 1 August 1995https://pubs.…
Comparou-se as características químicas, físicas e mineralógicas de Latossolos Roxos desenvolvidos de rocha alcalina (LRe) e de rocha eruptiva básica (LRd), da região de Jaboticabal, SP. Os resultados indicaram que o LRe apresenta-se num estádio de desenvolvimento, comparativamente, menos evoluído que o LRd, enquanto…
Single crystals of KMnPO 4 grown in a KCl flux show ferroelastic domains. The structure was determined on an optically controlled single domain crystal by X-ray diffraction methods. The cell is triclinic with dimensions a = 5.4813(5), b = 8.627(1), c = 8.887(1), in Å, α = 87.73(1)°, β = 89.10(1)°, γ = 88.01(1)°, Vᴍ =…
Abstract The fraction <20 μ m of a bentonitic material was selected to study the transformation of smectite into illite under hydrothermal conditions. Powder XRD showed that the studied material was composed of 97% dioctahedral smectite and 3% of quartz, cristobalite and plagioclase. The XRD analysis of the oriente…
A novel gene, roaA (ribosomal operon-associated gene), encoding a potential RNA-binding protein has been identified in the rpl23 ribosomal protein operon of the Euglena gracilis chloroplast genome. The roaA gene is interrupted by one group III and three group II introns. Introns 1 and 2 of roaA can be interpreted as a…
Abstract Fluorescence of several new polyimides in which neighboring imides are linked by a N‐N bond was examined in chloroform solutions. For the naphthalene‐containing polyimide 1 , analysis of the emission, excitation, and absorption spectra at different concentrations showed the existence of a ground‐state intermo…
We have studied morphological changes of an interface in a strong electric field which is normal to the initially planar interface. Electromigration along the interface in a two phase metallic system A-B of the immiscible components has been considered. The stresses arising during electromigration of the components we…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTModification of Crystallization Properties of Poly(ethylene terephthalate) by Copolymerization with Arylate Units. 1. Preparation and Isothermal Crystallization of 4,4'-Biphenol-Containing CopolymersYoshimitsu Sakaguchi, Masami Okamoto, and Itsuro TanakaCite this: Macromolec…
A detector has been devised able to measure with high resolution the primary ionisation yield in tissue-equivalent gas volumes of a few nanometres equivalent length. The sensitive ionisation volume is a wall-less millimetric region defined by a properly shaped electric field. Free electrons creased by the radiation in…
A two-dimensional computational model is used to evaluate the potential for cavitation to occur inside the brain material during head impact. The model represents a simple water-filled 14-cm-diameter, 5-cm-deep cylinder. For the purpose of our study, this cylinder represents the skull while the water inside the cylind…
The stability and high reversibility of the polyiodide equilibrium results in a positive redox couple useful in fuel, battery, and photoelectrochemical solar cells I − + I 2 ⇆ I 3 − ; I 3 − + 2 e − ⇒ 3 I − ; E 0.01 m I 2 , 1 m NaI = 298 mV vs . Ag / AgCl A further positive shift of polyiodide redox couples which can m…
We have studied the structure of a side chain cholesteric macromolecule by transmission electron microscopy. Up to now, the structure of cholesteric polymers has usually been studied by optical microscopy, and sometimes by scanning electron microscopy, but rarely by transmission electron microscopy, because of the dif…
PURPOSE: To assess the effectiveness and safety of normal and high doses of Gadobutrol versus a standard dose of Gadolinium DTPA in the MR evaluation of patients with brain metastases. MATERIAL AND METHODS: In a clinical phase-II study 20 patients who had been diagnosed as having brain metastases with CT or MRT were s…
Microporous carbons have been prepared by thermal treatment of poly (4-styrenesulfonate) derivative of MgAl hydrotalcites and subsequently the carbons extracted from the matrix. The interlayer carbonization process and the characteristics of the carbonaceous materials were studied by X-ray diffraction, inverse gas ch…
Landau-Devonshire theory1 is a useful phenomenological model to describe the properties of ferroelectric phase transitions. Below the transition temperature, the Landau model can be generalized to describe the thermodynamic stability of a ferroelectric crystallite in a bistable polarized configuration, and to predict…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNew Metal Carbonyl Complexes of Mixed Group 15/16 Anions: Structural Characterization of [Fe(As3Se3)2(CO)]2-, [Mn(As3Se5)(CO)3]2-, and [Fe2(AsTe4)2(CO)4]2-Thomas M. Martin, Paul T. Wood, George L. Schimek, William T. Pennington, and Joseph W. KolisCite this: Inorg. Chem. 199…