Materials Literature
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The main characteristics of a PZT ceramic, such as the piezoelectric charge coefficient or the permittivity, may change drastically when the ceramic undergoes a high uniaxial stress along its polar axis in the 10 to 150 MPa range. A special device has been built to measure accurately and directly the d33 and ϵT 33 par…
Mixtures of alumina and silica containing 68–78 wt% alumina react above 600°C with 0.5 mol of SiF 4 per mole of alumina to form fluorotopaz. High‐resolution X‐ray powder diffraction data were used to determine very accurate cell parameters of fluorotopaz as a function of 1 wt% compositional increments. The samples con…
Abstract The synthesis and thermal properties of a new type of side‐chain liquid‐crystalline polysalts are described. The polymers are first obtained by partial or complete alkylation of a linear poly(ethyleneimine) with 6‐(4‐methoxy‐4′‐biphenylyloxy)hexyl bromide or 12‐(4‐methoxy‐4′‐biphenylyloxy)dodecyl bromide. In…
We present experimental results on the study of the length dependence of molecular second-order nonlinear optical responses based on a new class of heteroaromatic compounds. We observed a power-law dependence of the second-order molecular susceptibility on the length of the molecule with an exponent of 2. The exponent…
This paper presents results of the Monte Carlo simulation of dense melts of symmetric diblock copolymer rings using the cooperative motion algorithm. Due to topological constraints, i.e., the entire absence of entanglements prevents the self-avoiding ring melts from adopting Gaussian statistics, and the scaling expone…
A new layered compound, Fe(H2O)2Ni(CN)4·2G (G=1,4-dioxane) has been characterized by single crystal X-ray analysis and 57Fe Mossbauer spectroscopy. The host layer comprises a close-2D network of [FeNi(CN)4]∞, from which a pair of water ligands protrude above and below the layer at Fe(II). The guest molecules, 1,4-diox…
Abstract Vented extruder devolatilization (DV) of PS melt containing 6,000 ppm styrene was studied by scanning electron microscopy (SEM) and video photography. Vacuum DV of a polymer is accompanied by foaming, which starts instantaneously upon supersaturation of the stretched melt and is enhanced at higher speeds of t…
Voidites in purely type IaB diamonds, in which the former are found in random distributions not associated with transformed {001} platelets, have been studied in detail. The evidence from extra, subsidiary spots seen in the electron diffraction patterns from volumes of crystal containing voidites, and from Moiré fring…
The central feature of the complicated structure of Na[Eu3(p-sulfonatocalix[4]arene)2(OH2)18(ONC5H5)3]·14 H2O is the coordination sphere of one of the three independent europium atoms. Its first coordination sphere consists of seven water molecules, the oxygen atom of a pyridine N-oxide molecule, and a sulfonate oxyge…
O comportamento térmico de diferentes materiais de cobertura foi estudado através dos índices de conforto. Para as condições de verão, estudou-se o efeito do índice de Temperatura de Globo e Umidade (ITGU) e da Carga Térmica Radiante (CTR) no interior de abrigos. As telhas de fibra transparente, alumínio e zinco foram…
A discussion is given of all possible two-dimensional (2D) quasicrystal structures with a six-dimensional (6D) embedding space. Such quasicrystals have some properties different from the properties of known 2D quasicrystals. It is predicted that the diffraction pattern of the quasicrystal structures considered here ca…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTriphenylcarbinol Derivatives as Molecules for Second-Order Nonlinear OpticsE. Kelderman, W. A. J. Starmans, J. P. M. van Duynhoven, W. Verboom, J. F. J. Engbersen, D. N. Reinhoudt, L. Derhaeg, T. Verbiest, K. Clays, and A. PersoonsCite this: Chem. Mater. 1994, 6, 4, 412–417…
The feasibility of using selected hardwoods and a hardwood pulp in wood-cement composites was investigated by determining the effects of hydration time, mild chemical modification, and the cement-to-wood ratio. The results indicated that as hydration time increased, the compressive strength increased. Some of the inhi…
The healing characteristics of polymer-coated Dacron grafts with or without heparin-bonding and collagen-coated Dacron grafts are compared with standard knitted Dacron grafts by implanting eight of each graft into pig iliac arteries. The grafts were implanted at random bilaterally with end-to-side anastomoses. The gra…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHigh-Temperature Single-Crystal X-ray Diffraction Studies of Potassium and (Cesium, Potassium) Titanyl ArsenatesPaul A. Northrup, John B. Parise, L. K. Cheng, L. T. Cheng, and E. M. McCarronCite this: Chem. Mater. 1994, 6, 4, 434–440Publication Date (Print):April 1, 1994Publ…
Abstract Pseudomonas oleovorans was grown separately on the methyl, ethyl and tert ‐butyl esters of octanoic, nonanoic and decanoic acid in attempts to obtain poly(β‐hydroxyalkanoates), PHAs, with ester groups at the terminal position of the β‐substituent. The growth rate increased from methyl to tert ‐butyl esters, b…
Abstract Tri- and dibromination of methyl-, dimethyl-, and trimethylbenzenes with N-bromosuccinimide were accomplished by photothermal reaction with a tungsten lamp in carbon tetrachloride or benzene. (Dibromomethyl)arenes and (tribromomethyl) derivatives were produced depending upon a solvent used and a substituent o…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLuminescence Spectroscopy of Europium(III) Nitrate, Chloride, and Perchlorate in Mixed Ethanol-Water SolutionsM. J. Lochhead, P. R. Wamsley, and K. L. BrayCite this: Inorg. Chem. 1994, 33, 9, 2000–2003Publication Date (Print):April 1, 1994Publication History Published online…
Novel functional biodegradable polyesters and polycarbonates have been prepared by copolymerization of either succinic anhydride or carbon dioxide with the glycidyl ethers of protected alditols, such as glycidylisopropyl ideneglycerol and glycidyldiisopropylidenepentitols, and their mixtures with propylene oxide in th…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructural characterization of 1,3-cyclodisiloxanesHonglae Sohn, Robin P. Tan, Douglas R. Powell, and Robert WestCite this: Organometallics 1994, 13, 4, 1390–1394Publication Date (Print):April 1, 1994Publication History Published online1 May 2002Published inissue 1 April 199…