Materials Literature
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In order to describe the local orientation of a macroscopic medium with broken rotational symmetries, an orientational field that consists of three orthonormal vectors is introduced. Next, the deformation free-energy density is constructed and a detailed acount is given of the form and number of the appearing surface…
Abstract A series of chromium‐promoted copper catalysts with various Cr to Cu molar ratios were prepared with the co‐precipitation method. The promotional effects of chromium on copper catalysts were examined by X‐ray powder diffraction (XRD), nitrous oxide decomposition, and the dehydrogenation reaction of ethanol. T…
Abstract through sequential copolymerization of appropriate ethylene‐propene mixtures into a preformed polypropene, or sligthly modified polypropene matrix (PP), it was possible to achieve and optimize some important property balances of the resulting multiphase copolymers, by finely tuning both the nature of the vari…
Abstract Pronounced relaxation peaks occurring in the magnetic after‐effect (MAE) spectra of low‐temperature electron‐irradiated single‐crystalline magnetite (Fe 3 O 4 ) are numerically analyzed and associated with anisotropic point defect configurations. As basic defects, cation interstitials and octahedral vacancies…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOrthocyclophanes. 3. Ketonands, Novel Ketonic Crowns of Polyoxo[1n]orthocyclophane ConstitutionWoo Young Lee, Chang Hee Park, Hyo-Joong Kim, and Sangsoo KimCite this: J. Org. Chem. 1994, 59, 4, 878–884Publication Date (Print):February 1, 1994Publication History Published onl…
The defects induced by high-dose (10 MGy) gamma irradiation (60Co) are studied in various types of high-purity silica glasses [including synthetic crystal (α-quartz)]. While the defects induced by gamma irradiation of up to 1 MGy have been reported to be generated through the bond breaking of manufacturing-method-depe…
The crystal and molecular structures together with the magnetic susceptibilities of a series of [M(en)3]3+ (M = Cr, Co) derivatives are reported. The space group and unit cell dimensions of [Cr(en)3]3[FeCl6]Cl6·H 2O (1), [Co(en)3]3[FeCl6]Cl6·H 2O (2), and [Cr(en)3] [FeCl4]Cl2·9H2O (3) are as follows: (1) R3, a = 15.44…
The martensitic transformation and the shape memory effect in Fe-Mn-Si alloys received great attention recently due to its potential commercial value. In this paper, the mechanisms for the martensitic transformation and various parameters influencing the shape memory effect like alloy composition, applied stress, pres…
This study investigates new techniques for measuring the influence of fiber, type on fabric surface vapor pressure and temperature, which are related to sensations of cloth ing comfort. Microfine hygrometry and thermometry are used to measure dynamic changes in moisture vapor pressure and temperature on both surfaces…
The diketonate Schiff-base complexes shown below were investigated, and the square planar derivatives (M=Ni, Cu, Pd) were found to display discotic hexagonal disordered phases (Dhd). The M=VO analogs are not liquid crystalline. None of the complexes can exhibit a disc-shape independently, and in the mesophase they mus…
Abstract The photo‐ and thermooxidative degradation of different grades of high‐impact polystyrene (HIPS) has been studied by FT‐IR spectroscopy. The oxidized films were treated with NH 3 and SF 4 for the rapid identification and resolution of the various carbonyl species, alcohols, and hydroperoxides. All the sample…
Abstract Hydration behavior of Na-smectite crystals synthesized at a pressure of 5.5 GPa and temperatures of 1400°–1500°C was examined by X-ray powder diffraction at various relative humidities (RH) in the range of 0–100%. The basal spacing of the Na-smectite crystal increased stepwise with increase in RH. The reflect…
Readily available chiral aldehydes and pyrrole provide porphyrins like 1 in a single step. Mn-Cl derivatives of such compounds are effective catalysts for the enantioselective epoxidation of nonfunctionalized olefins. The design of chiral porphyrin ligands should receive new impetus, since in the synthesis of 1, the D…
Two new protein kinase C inhibitory glycosides, vanicosides A [1] and B [2] were isolated from Polygonum pensylvanicum (Polygonaceae) by chromatographic techniques guided by bioassays for PKC inhibition. The structures of these glycosides were established primarily by analysis of 1H- and homonuclear correlated nmr and…
Abstract The synthesis and spectroscopic characterization of several benzoanellated [5.5.5]‐, [5.5.5.6]‐, and [5.5.5.5]fenestranes, including the parent difuso ‐centrotriindan 7 , the parent tetrafuso ‐centrotetraindan 8 (“fenestrindan”) as well as the tribenzo[5.5.5.6]‐ and tribenzo[5.5.5.5]fenestranes 27 and 35 , ar…
The gamma-aminobutyric acid (GABA) receptor is an abundant neuronal receptor in the mammalian and invertebrate nervous systems and is associated with an inhibitory chloride ion channel. GABA is the endogenous neurotransmitter for the receptor and can trigger both fast activation and a reversible desensitization of the…
Electrical properties of different compositions of lead vanadate glasses are reported in the temperature range 80--500 K. The experimental results are analyzed with reference to theoretical models existing in the literature. It has been observed that at high temperatures, Mott's model of phonon-assisted small polaron…
ADVERTISEMENT RETURN TO ISSUEPREVArticleIn Situ Synthesis of Ferrites in CellulosicsLouise Raymond, J.-F. Revol, D. H. Ryan, and R. H. MarchessaultCite this: Chem. Mater. 1994, 6, 2, 249–255Publication Date (Print):February 1, 1994Publication History Published online1 May 2002Published inissue 1 February 1994https://p…
Lattice defects in five wurtzite crystals, ZnO, BeO AlN GaN and InN, have been studied by high-resolution electron microscopy for samples pulverized at room temperature. High-density stacking faults were produced in BeO and GaN. With the weak-beam technique, dissociation of basal dislocations was observed in BeO. By h…
Molecular dynamics simulations have been carried out for sinple point charge (SPC) water, in normal, compressed, and stretched states. A detailed analysis of local structures using both pair correlation and Voronoi polyhedra distribution, which describes the information about the multiparticle distribution, was report…