Materials Literature
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Abstract Thermal analysis and wide‐angle x‐ray diffraction were used to assess the crystallinity for a series of poly(vinyl chloride) (PVC) samples, and the use of two complementary techniques was found beneficial. Two polymers were studied; a commercial suspension grade PVC, and an experimental grade of higher syndio…
The thermopower of the organic superconductor \ensuremath{\kappa}-(BEDT-TTF${)}_{2}$Cu[N(CN${)}_{2}$]Br single crystals has been measured in two crystallographic directions a and c within the most conducting organic donor molecule plane. [Here BEDT-TTF represents bis(ethylenethio)-tetrathiafulvalene.] While the thermo…
In the KTiOPO4 (KTP) structure, it is shown that there are hole sites related by pseudosymmetry to the inequivalent potassium sites K(1) and K(2). The formation of twin domains is through a twofold rotation with the principal feature of the twinning being the displacements of the K atoms onto their respective hole sit…
Abstract The clay mineralogy of the Miocene Monterey Formation was determined for onshore and offshore sequences in the Santa Maria basin area, California. The <0.1- μ m fraction of clayey, opal-CT porcelanites, siliceous mudstones, and dolostones from the Pt. Pedernales area consists of mixed-layered illite/smecti…
Previous studies have shown the effectiveness of partially resorbable arterial prostheses in the rabbit. This study compares these same compound prostheses with commercial graft materials in the dog. Conduits 4 mm inner diameter X 50 mm in length were woven from composite yarns containing 69% polyglactin 910 (PG910)/3…
Microstructural and compositional changes during heat treatment of sol–gel‐derived mullite fibers with additions of 2 wt% B 2 O 3 , 2 wt% P 2 O 5 , 2 wt% Cr 2 O 3 , and (1 wt% P 2 O 5 + 1 wt% Cr 2 O 3 ) were compared with those of undoped mullite fibers. For all compositions the sequence of phase development was the c…
Abstract Liquid‐crystalline silsesquioxanes were synthesized by combining mesogens with spherical silsesquioxanes. Most of the synthesized compounds exhibit smectic phases. Lateral connection of a mesogen results in a nematic phase. All phases are optical uniaxial positive, i.e. calamitic structures are favoured. LC‐s…
Chinese NiTi wire was compared with Nitinol and stainless steel wires in a combined laboratory and clinical examination. In the laboratory test, the loading and unloading-deflection properties of the wires were determined in a three-point bending test and their surface properties were studied in a scanning electron mi…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCage escape yields in the quenching of tris (2,2'-bipyridine)ruthenium(II) by methylviologen: presence of triethanolamine as a sacrificial electron donorMikhael Georgopoulos and Morton Z. HoffmanCite this: J. Phys. Chem. 1991, 95, 20, 7717–7721Publication Date (Print):Octobe…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotochemically controlled ion permeability of liposomal membranes containing amphiphilic azobenzeneTomoo Sato, Masato Kijima, Yoshihiro Shiga, and Yoshiro YonezawaCite this: Langmuir 1991, 7, 10, 2330–2335Publication Date (Print):October 1, 1991Publication History Published…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPentacoordinate dihydridosilicates: synthesis, structure, and aspects of their reactivityRobert J. P. Corriu, Christian Guerin, Bernard J. L. Henner, and Qunjie WangCite this: Organometallics 1991, 10, 10, 3574–3581Publication Date (Print):October 1, 1991Publication History…
The current status of cobalt-59 NMR spectroscopy is reviewed including historical perspectives and application to various areas of coordination chemistry. Chemical shift data are summarized and tabulated for about 800 complexes from values in the literature and our experimental data. Spin-spin coupling constants are a…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTIncorporation of aluminum into silicate anions in aqueous and methanolic solutions of TMA silicatesR. F. Mortlock, A. T. Bell, and C. J. RadkeCite this: J. Phys. Chem. 1991, 95, 20, 7847–7851Publication Date (Print):October 1, 1991Publication History Published online1 May 20…
Abstract Permeation and separation characteristics for aqueous alcoholic solutions through a modified silicone rubber membrane containing poly(propylene glycol) in the polymer chain were studied by both pervaporation and evapomeation. Both the permeation rates in pervaporation and evapomeation increase, and the select…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSwitching the mechanism of spin-exchange coupling in (.mu.-oxo)bis(.mu.-carboxylato)divanadium(III) complexes by protonation of the oxo bridgePetra Knopp and Karl WieghardtCite this: Inorg. Chem. 1991, 30, 21, 4061–4066Publication Date (Print):October 1, 1991Publication Hist…
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A theory based on an energy method is proposed for the mechanics of a fiber mass under general deformation, including compression, extension, and shearing. The mass , is treated as a network composed of many fiber segments, each bounded by two neigh boring fiber contact points, and the individual mechanical behaviors…
We report a first-principles simulation study of phase transitions in ${\mathrm{KNO}}_{3}$, using our recently developed method for treating ionic molecular solids. With the interionic potentials calculated from ab initio electron charge densities of the ions, our structural static relaxation gave close fits to both t…
The genes encoding the enzymes of IMP biosynthesis in Bacillus subtilis constitute the pur operon, whereas the genes encoding GMP biosynthetic enzymes, guaA (GMP synthetase) and guaB (IMP dehydrogenase), and the purA gene encoding adenylosuccinate (sAMP) synthetase all occur as single units. The purB gene encodes an e…
High transparent and conductive CdO films were prepared using the activated reactive evaporation technique on Corning 7059 glass substrates. The film resistivity and transmittance were found to be influenced by the glow power of the discharge. Electron mobilities of 4-28 cm 2 V -1 s -1 and carrier density in the range…