Materials Literature
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Inelastic neutron scattering studies have been performed on ferroelectric ${\mathrm{KNbO}}_{3}$ in its orthorhombic phase at room temperature. Dispersion curves up to 10 THz have been determined for phonons propagating along the [101], [010], and [111] pseudocubic directions. A detailed intensity map of the inelastic…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTConcerning the miscibility of PVC-PVAc blendsDorab E. Bhagwagar, Carl J. Serman, Paul C. Painter, and Michael M. ColemanCite this: Macromolecules 1989, 22, 12, 4654–4656Publication Date (Print):December 1, 1989Publication History Published online1 May 2002Published inissue 1…
Abstract Die Synthese von 2‐(9‐Anthryl)‐1,8a‐dihydro‐1,1‐azulendicarbonitril ( 1a ) über das Tetrahydroazulen 5a , ausgehend von 8‐Methoxyheptafulven ( 3 ) durch [8 + 2]‐Cycloaddition, wird beschrieben. Durch Bestrahlung mit sichtbarem Licht wird 1a in das Vinylheptafulven 2a umgelagert. Dieses wiederum kann unter the…
Abstract The electrochemical study clarified that ditetrazolium salts are reduced not only to the half-reduced “monoformazans” but also to the fully-reduced “diformazans” at the potential where the first electron is transferred to generate the “tetrazolinyl radical”. The key reaction leading to the simultaneous genera…
The three structural genes rhaA, rhaB and rhaD, that specify the enzymes rhamnose isomerase, rhamnulose kinase and rhamnulose 1-phosphate aldolase respectively, have been cloned from Escherichia coli K-12. The precise location of the genes has been determined by gene complementation analysis and by enzymatic assays of…
Cholesteric liquid crystals which have a helical arrangement of oriented chiral molecules are expected to show novel cross couplings between fluxes and forces. The most convincing demonstration of these couplings is through a dynamical effect on the structure. Though Lehmann found a rotation of the structure under a t…
The crystallization mechanism in Li 2 O‐Al 2 O 3 ‐SiO 2 (1 : 1 : 6) glasses was investigated with TiO 2 or Ta 2 O 5 as nucleation agents, by differential thermal analysis, X‐ray diffractometry, and transmission electron microscopy. Phase separation occurred prior to crystallization in all of the glasses studied. Both…
Spoilage by microorganisms growing on food surfaces is the shelf-life limiting factor for many food products. Previous publications have shown that this shelf-life limitation can be overcome by edible coatings lowering the diffusion rate into the food of antimicrobial agents applied on food surfaces. A permeability ce…
Aluminum-doped ZnO thin films were prepared by ionized deposition on glass substrates. The crystallinity and electrical properties of Al-doped ZnO films prepared by ionized evaporation depend on the deposition conditions. The c-lattice constant of ZnO films increases with ionization current and acceleration voltage. T…
The literature apertaining to XPS studies of three classes of organic coatings (polybutadiene, epoxy co-polymers, and fusion bonded epoxy) on steel are reviewed in the light of the current theories of cathodic disbondment. All three mechanisms (oxide reduction, polymer hydrolysis, and interfacial failure) are readily…
Phase transformations in Ti–50V alloys containing oxygen in the range <0·095–0·36 wt-% have been studied at 750 and 400°C for times up to 1000 h. Results of electron microscopy, X-ray diffraction, and hardness testing indicate that oxygen widens the α+β phase field at 750°C and the metastable β phase miscibility gap a…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCopper atomization mechanisms in graphite furnace atomizersPingxin. Wang, Vahid. Majidi, and James A. HolcombeCite this: Anal. Chem. 1989, 61, 23, 2652–2658Publication Date (Print):December 1, 1989Publication History Published online1 May 2002Published inissue 1 December 198…
Al 2 TiO 5 materials were sintered under different conditions to produce different grain sizes. The resultant microcracked materials exhibited a range of bulk thermal expansions which showed a strong correlation with average grain size. An Al 2 TiO 5 average grain size of 3 to 4 μm was the minimum at which the size an…
Aus Furfurylalkohol auf einfachem Wege konnte das überfällige Schwefel‐Analogon des Porphyrins, das Tetrathiaporphyrin‐Dikation 1 , als Perchlorat gewonnen werden. Den Schlüssel zur Synthese bildet der bemerkenswert glatt erfolgende O/S‐Austausch im Tetraoxaporphyrinogen. Das Ringgerüst von 1 ist nicht mehr planar. ma…
Calculations are performed on a series of p-substituted aniline for which corrosion activities have been reported, using semi-empirical molecular orbital method. Approximate ground-state electronic properties are obtained for each molecule studied. Significant correlations are obtained between corrosion rate and corro…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA cyclic octanuclear polyoxoalkoxy vanadate(IV) with an oxalate-binding cavity, [(n-C4H9)4N]2[V8O8(OCH3)16(C2O4)]. Structural comparison with the analogous polymolybdates(V) complex [(n-C4H9)4N]2[Mo8O16(OC2H5)8(C2O4)]Qin Chen, Shuncheng Liu, and Jon ZubietaCite this: Inorg.…
The application of X-ray absorption spectroscopy (XAS) to the study of diffusion properties of oxide glasses and glass surfaces is considered. Mixed alkali silicates, the chemical resistance of iron-lead-phosphate glasses and the surface structure of uranium in leached borosilicate glasses are discussed. Results are i…
Equilibrium binding studies demonstrate that purified Escherichia coli isocitrate dehydrogenase binds isocitrate, alpha-ketoglutarate, NADP, and NADPH at 1:1 ratios of substrate to enzyme monomer. The phosphorylated enzyme, which is completely inactive, is unable to bind isocitrate but retains the ability to bind NADP…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXT1,2,3,5-Diselenadiazolyls as building blocks for molecular metals. Preparation and structures of [PhCN2Se2]+PF6- and [PhCN2Se2]2Paul Del Bel Belluz, A. Wallace Cordes, Eva M. Kristof, Peter V. Kristof, Stephen W. Liblong, and Richard T. OakleyCite this: J. Am. Chem. Soc. 198…
This paper reviews the brittle fracture behavior of dielectric ceramics such as barium titanate, and describes some of the relationships between defects such as cracks and electrical degradation and failure of multilayer capacitors. Stresses arising from the ferroelectric phase transformation in these dielectric mater…