Materials Literature
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Abstract Thermal characteristics of radiation‐grafted FEP‐g‐polystyrene copolymer films were evaluated using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The grafting of polystyrene onto FEP film introduced a two‐step degradation pattern where polystyrene degradation occurred in the ra…
The fluorescence of ${\mathrm{Pr}}^{3+}$:${\mathrm{LaCl}}_{3}$, ${\mathrm{PrCl}}_{3}$ and ${\mathrm{Nd}}^{3+}$:${\mathrm{LaCl}}_{3}$, ${\mathrm{NdCl}}_{3}$ has been measured up to pressures of 10 GPa. In addition the structural parameters of ${\mathrm{PrCl}}_{3}$ and ${\mathrm{GdCl}}_{3}$ have been obtained up to 8 GP…
The reaction of (E)-4,5-epoxy-(E)-2-heptenal with butylamine and glycine methyl ester produced brown macromolecular pigments, which showed fluorescent characteristics similar to lipofuscins. This polymerization reaction implies in the first step the formation of 1-alkyl-2-(1'-hydroxyalkyl)pyrroles (IV, VI). Compounds…
In disordered fractal or nonfractal systems, the disorder induces rapid fluctuations of the acoustical vibrational wave functions, so that statistics can be used to resolve the problem of Raman scattering from localized low-energy vibrations. We derive the expressions of light-vibration coupling coefficient, C(ω), as…
Remarkably aromatic are the diaza[26]annulenes of type 1, which are stabilized by pyrrole rings positioned at the corners. This has been proven by 1H NMR spectroscopy, crystal structure analysis, and by electrophilic substitution reactions. In contrast, for the simple annulenes (CH)n, the aromaticity “stops” at the 22…
Cristobalite is formed when borosilicate glass (Corning Code 7740) is sintered at temperatures ranging from 700 o to 1000 o C. The precipitation kinetics, determined by XRD analysis, exhibit a characteristic incubation period which decreases with increasing sintering temperature, from 60‐120 min at 700 o C to 3‐5 min…
A selective film‐formation technology using liquid‐phase deposition (LPD) around room temperature for fully planarized multilevel interconnections is developed. The LPD technique utilizes supersaturated hydrofluosilicic acid aqueous solution as a source liquid. The films can be selectively formed on chemical vapor dep…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and magnetic properties of a binuclear copper(II) complex with a .mu.-1,2-squarato coordination mode. Crystal structure of (.mu.-1,2-squarato)bis[(N-(2-(diethylamino)ethyl]salicylidenaminato)aquacopper(II)] hydrateC. E. Xanthopoulos, M. P. Sigalas, G. A. Katsoulos,…
Thermally stimulated depolarization current (TSDC), thermal sampling (TS) TSDC, and dielectric spectra of poly(p-phenylene sulfide) (PPS) were measured in the vicinity of the glass transition temperature Tg. The global TSDC spectra of amorphous PPS with varying the poling temperature revealed the presence of two TSDC…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSoluble polyimides with polyalicyclic structure. 2. Polyimides from bicyclo[2.2.1]heptane-2-exo-3-exo-5-exo-6-exo-tetracarboxylic 2,3:5,6-dianhydrideMasao Yamada, Masatoshi Kusama, Toshihiko Matsumoto, and Toshikazu KurosakiCite this: Macromolecules 1993, 26, 18, 4961–4963Pu…
The crystal structures of 13 alkali amphiboles have been refined to R values of 1-2% using single-crystal MoKα x-ray data. Crystals used in the collection of the intensity data were subsequently analyzed by elecrton and ion micrprobe. Site occupancies were assigned by site-scattering refinement and stereochemical cons…
The crystal structure of the enzyme-substrate complex of p-hydroxybenzoate hydroxylase from Pseudomonas fluorescens shows that the hydroxyl group of 4-hydroxybenzoate interacts with the side chain of Tyr201, which is in close contact with the side chain of Tyr385. The role of this hydrogen bonding network in substrate…
Measurements have been made of the temperature dependence of CH3, CH4, and C2H2 very near the substrate during filament-assisted diamond growth. CH3 was detected using (2+1) resonance-enhanced multiphoton ionization (REMPI), and CH4 and C2H2 concentrations were measured using sampling mass spectrometry. A strong depen…
The in vivo folding of subtilisin is dependent on a 77 amino acid propeptide, which is eventually cleaved from the N-terminus of subtilisin to create the 275 amino acid mature form of the enzyme (Ikemura et al., 1987). We have cloned, expressed, and purified large quantities of the 77 amino acid subtilisin propeptide.…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis of gold [Au3]3+, gold-silver [Au2Ag]3+, and gold-copper [Au2Cu]3+ loose clustersJose Vicente, Maria Teresa Chicote, and Maria Cristina LagunasCite this: Inorg. Chem. 1993, 32, 17, 3748–3754Publication Date (Print):August 1, 1993Publication History Published online1…
In this paper concerning the synthesis of microporous ceramic membranes, we focus on the preparation and ther‐ mal stability of unsupported microporous TiO 2 ‐ZrO 2 , mixed‐oxide membranes. It has been observed that, by add‐ ing up to 20% ZrO 2 , into TiO 2 , or up to 10% TiO 2 , into ZrO 2 , these microporous membran…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMorphology of a lamellar diblock copolymer aligned perpendicular to the sample plane: transmission electron microscopy and small-angle X-ray scatteringKaren I. Winey, Sanjay S. Patel, Ronald G. Larson, and Hiroshi WatanabeCite this: Macromolecules 1993, 26, 16, 4373–4375Publ…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHeterolytic oxygen-oxygen bond cleavage of peroxy acid and effective alkane hydroxylation in hydrophobic solvent mediated by an iron porphyrin coordinated by thiolate anion as a model for cytochrome P-450Tsunehiko Higuchi, Kousei Shimada, Naho Maruyama, and Masaaki HirobeCit…
The development of toughened ceramics over the past 10 to 15 years is arguably one of the most important materials breakthroughs of this century. Monolithic and composite ceramic materials having fracture toughnesses up to an order of magnitude higher than those available 20 years ago have been produced using technolo…
In Substanz explosiv ist der Bis(η 2 ‐peroxo)‐Komplex 1 , der in Lösung die aktive Spezies bei der Epoxidation von Olefinen mit [CH 3 ReO 3 ] ist und als Diglyme‐Addukt 2 auch röntgenstrukturanalytisch charakterisiert werden konnte. Unter Katalysebedingungen (H 2 O 2 ‐Überschuß) ist 1 ungleich beständiger als im freie…