Materials Literature
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X‐ray absorption spectra at Zr‐ K , Ce‐L 111 and Ge‐ K edges in ZrO 2 –CeO 2 and ZrO 2 –GeO 2 solid solutions have been measured at 10 K. Both Ce and Ge substitute for Zr in the cation network, but CeO 8 and GeO 4 polyhedra are maintained around the dopants. The oversized CeO 8 is compressed to a Ce–O distance of 2.30…
Theor. models for the action spectrum and the current-voltage characteristics of microporous (colloidal) semiconductor films in photoelectrochem. cells were derived. The derivation is based on the assumptions that the charge carrier transport in the semiconductor occurs via diffusion, and that the diffusion length is…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDoped LaGaO3 Perovskite Type Oxide as a New Oxide Ionic ConductorTatsumi Ishihara, Hideaki Matsuda, and Yusaku TakitaCite this: J. Am. Chem. Soc. 1994, 116, 9, 3801–3803Publication Date (Print):May 1, 1994Publication History Published online1 May 2002Published inissue 1 May…
Abstract A new tetraphenylated heterocylic diol, 2,5‐bis(4‐hydroxyphenyl)‐3,4‐diphenylpyrrole, was synthesized in three steps starting from 4‐methoxydeoxybenzoin. The tetraphenylpyrrole‐containing polyarylates having inherent viscosities of 0.28–0.88 dL/g were prepared from the diol and various aromatic dicarboxylic a…
Abstract Packing density and gas permeability of a three‐component copolymide series is presented. The three‐component polyimides are prepared a via “stepwise” synthesis procedure that goes through the acid anhydride terminated pre‐polymer. The procedure ensures the statistical distribution of segments of the polymers…
Abstract Formation of SiO 2 –B 2 O 3 gel fibers and oxides was investigated by the sol‐gel method using tetraacetoxysilane (TAS) and boron tri‐ n ‐butoxide (BTB). Low molecular weight borosiloxanes (BS) were formed by the reaction of TAS with BTB in THF. Partial alkoxylation and hydrolysis of BS followed by further co…
Abstract The curing of epoxidized natural rubber with p ‐phenylenediamine catalyzed by bisphenol A was investigated. The curing reaction was found to be first order with respect to the amine and to have an activation energy of 67.5 kJ/mol. Vulcanizates of tensile strength 12.5–16.0 MPa were obtained at cure times of 3…
Abstract Glycine/glycolic acid based biodegradable copolymers have been prepared by ring‐opening homopolymerization of morpholine‐2,5‐dione, and ring‐opening copolymerization of morpholine‐2,5‐dione and glycolide. The homopolymerization of morpholine‐2,5‐dione was carried out in the melt at 200°C for 3 min using stann…
Abstract The crystallization kinetics of polypropylene (PP), polyamide (PA66), and poly(ethylene terephthalate) (PET) were studied, using a pressure dilatometer (to 200 MPa) to follow the volume changes associated with the crystallization process. The commonly used Avrami equation fitted the isothermal/isobaric crysta…
Abstract Chemical reactivity of β‐chitin isolated from squid pens has been examined in various reactions to elucidate the possibility of facile modifications in simple manners leading to the preparation of derivatives with well‐defined structures. β‐Chitin swelled in common solvents such as methanol and pyridine unlik…
Abstract The a posteriori error estimates based on the post‐processing approach are introduced for elastoplastic solids. The standard energy norm error estimate established for linear elliptic problems is generalized here to account for the presence of internal variables through the norm associated with the complement…
A central question in molecular biology concerns the means by which a regulatory protein recognizes different targets. IIIGlc, the glucose-specific phosphocarrier protein of the bacterial phosphotransferase system, is also the central regulatory element of the PTS. Binding of unphosphorylated IIIGlc inhibits several n…
Abstract The compression creep behavior was monitored at constant temperature and/or relative humidity for two slabstock foams with different hard‐segment content. The tests were performed by applying a constant load (free falling weight) and then monitoring the strain as a function of time over a 3‐h time period. A n…
In soft-mode structural phase transitions the Ginzburg temperature interval in which fluctuations and the interactions between them become important is often observed to be small on the scale of the transition temperature. We consider the size of the Ginzburg interval (GI) in framework and 'cogwheel' structures using…
Abstract A semi crystalline polymer, polyamide, was processed using a new technique. The technique is that of mechanically grinding the material using large inputs of energy at temperatures below the glass‐transition temperature and then later reconstituting the material by applying pressure and holding at a temperatu…
X-ray, M\"ossbauer spectroscopy, and extended x-ray absorption fine structure studies provide an atomic-scale description of the pressure-amorphized ${\mathrm{Ge}}_{4}$. At P>12 GPa a gradual onset of structural disorder accompanied by a molecular-association process is observed. An amorphized state concurring with…
Results from magnetically induced birefringence measurements on pentylcyanobiphenyl in Vycorlike porous glass are reported. We find that the Cotton-Mouton coefficient exhibits sigmoidal behavior with temperature, consistent with changes in the direction and possibly the magnitude of a nonzero tensor order parameter, e…
The photovoltaic behavior and spectral response of n-type (nitrogen-doped) tetrahedral amorphous carbon (ta-C)/p-type crystalline silicon heterojunction photodiodes are reported. Abrupt step junction type characteristics are observed with ta-C films ranging in thickness from 40 to 160 nm. The photovoltage increases an…
Abstract The relaxation behavior of the load in compression and the stress in tension was monitored at constant temperature and/or relatively humidity for a set of four slabstock foams with varying hard‐segment content as well as two of the compression molded plaques of these foams. The majority of the compression rel…
An understanding of heteroepitaxy between perovskite and alkaline earth oxides is developed in terms of ion size and interfacial electrostatics. Interfacial energy minimization at the first atomic layers is the basis for a commensurate, unit-cell stability. This unit-cell stability presents the opportunity to study re…