Materials Literature
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Laser excited photoluminescence of InSe single crystal shows three peaks at 1.311, 1.272, and 1.227 eV. The relative intensity of these peaks variation from point to point on the surface of the crystal. The high-energy peak is assigned to impurity to band transitions, the 1.277 eV to donor-acceptor type transition and…
As in conventional high temperature technology, the qualification of metallic materials for high temperature reactor (HTR) applications is based on creep behavior, fatigue properties, corrosion resistance, and thermal stability. Of specific interest are the effects of the primary coolant helium, which contains trace i…
Abstract The environmental stress crazing and cracking (ESC) behavior of an aromatic polyetherimide (PEI) has been characterized in a wide spectrum of organic liquids and compared to the behavior of several other glassy thermoplastics. PEI's response is qualitatively similar to that of the other resins for each of whi…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTProperties of low molecular weight block copolymers. 4. Differential scanning calorimetry and refractive index-temperature measurement on styrene-butadiene diblock copolymers and styrene-butadiene-styrene triblock copolymersSonja Krause, Zhonghe Lu, and Magdy IskandarCite th…
The specific heat of antiferromagnetic ${\mathrm{Cs}}_{2}$Fe${\mathrm{Cl}}_{5}$ \ifmmode\cdot\else\textperiodcentered\fi{} ${\mathrm{H}}_{2}$O between 1 and 30 K is reported. The long-range ordering temperature is 6.54\ifmmode\pm\else\textpm\fi{}0.02 K. A careful examination of the possible superexchange paths, and th…
Abstract The degree of dispersion of carbon black in rubber is known to be a determining factor in the physical properties of the composite. It is important, therefore, to have a reliable, quantitative technique for assessing carbon black dispersion. It has been known for some time that the degree of dispersion of car…
Hot‐pressed Si 3 N 4 materials containing 1 and 5 wt% MgO were oxidized for 1000 h at 1000°, 1100°, and 1200°C in helium at 0.4 to 0.8 Pa total oxidants. Transition from passive to active oxidation occurred between 1000° and 1100° C, in agreement with published theoretical calculations for pure Si 3 N 4 . The amounts…
Abstract The seven coordinate adducts of [Ln(fod)3]chelates are described. The NMR spectra of diamagnetic and paramagnetic adducts have been discussed. The europium, praseodymium and ytterbium adducts have been scanned as potential shift reagents and these seven coordinate adducts produce large dipolar shifts in the p…
Factor analysis has been used to resolve the overlapping XPS spectra obtained in the x-ray-induced transformation of Pt(en) 2 (OH) 2 Cl 2 to Pt(en) 2 Cl 2 . This is achieved without prior knowledge of the data set nor the establishment of any initial curve fitting criteria.
Abstract The primary fragmentation processes in the thermal decomposition of polymers were studied in detail on a series of structurally related polyureas by direct pyrolysis with a mass spectrometer. Our results indicate that polyureas I–III undergo a quantitative depolycondensation process analogous to that observed…
Central full-thickness perforating excision wounds were made in rabbit corneas and were examined by light and scanning electron microscopy at various times after wounding to study the three-dimensional morphologic changes in the tissue during healing and remodeling. Formation of a fibrin clot soon after wounding seals…
The excited-state absorption cross section\sigma_{2a}(E)in the gain wavelength region of alexandrite has been determined and is shown to limit the vibronic laser range at both high and low energy. The maximum in vibronic laser emission is due to a minimum in\sigma_{2a}(E)near 13 000 cm-1.\sigma_{2a}(E)is less than 10-…
True magnetoplumbite structures, e.g. Na l/2 La l/2 Al 1/2 O 19 , differ significantly from β‐alumina structures in leach resistance and thermal stability against volatilization. Na, K, Rb, and Cs can be safely immobilized in magnetoplumbite structures.
Abstract Reduction of carbon dioxide at p-type GaP photocathodes was investigated in lithium carbonate electrolytes. The reduction occurs in competition with hydrogen evolution and its current efficiency is enhanced by dissolving crown ether such as 15-crown-5 in the electrolyte. It is proposed that a chemical reactio…
A method for the characterization of coincidence cells is proposed for hexagonal crystals. It is based on a simple formulation of the orientation relationships for coincidence site lattices. Therefore tables of coincidence orientation are established for different axial ratios with rational values of (c/a)2. Possible…
Enzymes are often immobilized on the internal surfaces of porous solid by immersing enzyme-free particles in a well mixed solution of enzyme. The ensuing impregnation process involves coupled transient mass transfer and surface attachment of enzyme. A mathematical model is employed to explore the influences of process…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTUltradrawing at room temperature of high molecular weight polyethyleneMasaru Matsuo and R. St. John ManleyCite this: Macromolecules 1982, 15, 4, 985–987Publication Date (Print):July 1, 1982Publication History Published online1 May 2002Published inissue 1 July 1982https://pub…
A simplified procedure for the fractionation and purification of different collagen types from various tissues is described which is particularly efficient in separating type-V from type-IV collagen, and high-mol.-wt. (HMW) aggregates from 7 S collagen. Uterus and maternal villi contain 2 forms of type-V collagen - [a…
A new silicon-on-insulator (SOI) structure has been achieved by utilizing silicon molecular beam epitaxial (Si-MBE) growth on porous silicon, silicon island patterning, and the subsequent laterally enhanced oxidation of the porous silicon. The surface of Si-MBE film grown on porous silicon at 770 °C without high-tempe…
The gravimetric method was used to study the reaction between fused silica and silicate glasses with HF acid solution. The reaction was found to be transport‐controlled. Additions of Al 2 O 3 , CaO, or both to fused silica caused a reduction in corrosion resistance of the resulting glasses.