Materials Literature
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Abstract Aqueous Al passes from octahedral to tetrahedral coordination over a narrow pH interval, or threshold. This interval is 5.5–6.5 at 25°C and shifts to lower pH as temperature increases. The concentration of aqueous tetrahedrally coordinated Al is a quasi-step function of the solution pH, and, by the mass-actio…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOrganometallic reactions of rhodium octaethylporphyrin species in pyridine. Heterolytic cleavage of [(OEP)Rh]2 and metalloanion activation of carbon monoxideBradford B. Wayland, Kenneth J. Balkus Jr., and Maria D. FarnosCite this: Organometallics 1989, 8, 4, 950–955Publicati…
A comparative study was performed of the essential oil extracted from the fruiting apex of Bupleurum gibraltaricum Lamarck (Umbelliferae) collected in different areas within the province of Granada, including the Cázulas mountains, the Balcón de Canales and the Quéntar Reservoir. All three essential oils were very sim…
Abstract Layer charge and cation-exchange characteristics of weathered biotite isolated from a Gray Luvisol in Saskatchewan showed that this product was a high-charge vermiculite. Cation-exchange capacity (CEC) of the sand-size (100–250 μ m) weathered biotite particles from different horizons, as determined by a 30-mi…
The organic charge-transfer (CT) complexes that have a mixed-stack structure, in which organic electron donors and electron acceptors stack alternately plane to plane, such as perylene/tetracyanoethylene, showed larger third-harmonic generation than poly-(2,4-hexadiyn-1,6-diol-bis(p-toluenesulfonate), which is known a…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMagneto-structural correlations and metal-metal bonding in exchange-coupled nonahalodimolybdate (A3Mo2X9; X = chlorine, bromine, iodine) complexesRobert Stranger, Peter W. Smith, and Ian E. GreyCite this: Inorg. Chem. 1989, 28, 7, 1271–1278Publication Date (Print):April 1, 1…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMacroscopic ordering of liquid-crystalline polymers with discotic mesogensB. Hueser, T. Pakula, and H. W. SpiessCite this: Macromolecules 1989, 22, 4, 1960–1963Publication Date (Print):April 1, 1989Publication History Published online1 May 2002Published inissue 1 April 1989h…
Abstract The gas transport and other pertinent properties of three aromatic polyesters, made by reacting phenolphthalein with terephthaloyl chloride (PPha‐tere), 50:50 terephthaloyl and isophthaloyl chlorides (PPha‐50:50), and isophthaloyl chloride (PPha‐iso), are reported. The glass transition temperatures of PPha‐te…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPolymerization of monomers containing functional silyl groups. 6. Anionic polymerization of 2-(trialkoxysilyl)-1,3-butadieneKatsuhiko Takenaka, Takashi Hattori, Akira Hirao, and Seiichi NakahamaCite this: Macromolecules 1989, 22, 4, 1563–1567Publication Date (Print):April 1,…
A model is proposed in which protons fluctuate between neighboring atomic shells either by thermal activation or by a tunneling process. The transition probability of the protons depends on the distance between the adjacent atoms. The characteristic pair distribution function of interatomic distances in the amorphous…
The plastic behaviour of α-Ti single crystals with a very low impurity content has been studied at temperature between 4 and 300 K. Comparison with previous results is made. This study shows that the low-temperature plastic behaviour of α-Ti is controlled by lattice friction. The importance of substitutional impuritie…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEnd capping of growing species of poly(2-oxazoline) with carboxylic acid: a novel and convenient route to prepare vinyl- and carboxy-terminated macromonomersMasatoshi Miyamoto, Kensuke Naka, Makoto Tokumizu, and Takeo SaegusaCite this: Macromolecules 1989, 22, 4, 1604–1607Pu…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSilver-coated fumed silica as a substrate material for surface-enhanced Raman scatteringA. M. Alak and . Vo Dinh TuanCite this: Anal. Chem. 1989, 61, 7, 656–660Publication Date (Print):April 1, 1989Publication History Published online1 May 2002Published inissue 1 April 1989h…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTIsodimorphism in synthetic poly(β-hydroxybutyrate-co-β-hydroxyvalerate): stereoregular copolyesters from racemic β-lactonesSteven Bloembergen, David A. Holden, Terry L. Bluhm, Gordon K. Hamer, and Robert H. MarchessaultCite this: Macromolecules 1989, 22, 4, 1663–1669Publicat…
The linear- and nonlinear-optical properties of 2-cyclooctylamino-5-nitropyridine (COANP) have been investigated. The refractive indices exhibit strong dispersion and a high birefringence (0.15–0.3) in the visible. The three main refractive indices at λ = 550 nm are na = 1.700, nb = 1.845, and nc = 1.683. The calculat…
Experimental and modeling studies of the free-radical-induced degradation of polypropylene (PP) in the melt phase have been carried out. Experiments have been performed in a single-screw plasticating extruder using a peroxide as the free-radical source. Concentration of the peroxide was in the range 0.01–0.6 wt%. Resu…
SiC‐monofilament‐reinforced SiC or Si 3 N 4 matrix composites were fabricated by hot‐pressing, and their mechanical properties and effects of filaments and filament coating layers were studied. Relationships between frictional stress of filament/matrix interface and fracture toughness of SiC monofilament/Si 3 N 4 matr…
The longitudinal piezoelectric effect induced by a direct current bias field was investigated in PMN:PT family of relaxor ferroelectric ceramics in the frequency range from 0. 1 Hz to 50 kHz. The piezoelectric d 33 coefficient was studied by measuring the strain induced by the applied electric field. Under the 10 kHz…
Our studies, which are aimed at understanding the catalytic mechanism of the alpha subunit of tryptophan synthase from Salmonella typhimurium, use site-directed mutagenesis to explore the functional roles of aspartic acid 60, tyrosine 175, and glycine 211. These residues are located close to the substrate binding site…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectron transmission and inner-shell electron energy loss spectroscopy of acetonitrile, isocyanomethane, methyl thiocyanate, and isothiocyanatomethaneA. P. Hitchcock, M. Tronc, and A. ModelliCite this: J. Phys. Chem. 1989, 93, 8, 3068–3077Publication Date (Print):April 1, 1…