Materials Literature
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Flavocytochrome b2 from Saccharomyces cerevisiae acts physiologically as an L-lactate dehydrogenase. Although L-lactate is its primary substrate, the enzyme is also able to utilize a variety of other (S)-2-hydroxy acids. Structural studies and sequence comparisons with several related flavoenzymes have identified the…
Abstract A series of new poly(arylene ether phenyl‐s‐triazine)s was prepared by the nucleophilic aromatic substitution polymerization of the potassium salt of bisphenols with 2,4‐bis (halophenyl)‐6‐phenyl‐s‐triazine in N ‐methyl‐2‐pyrrolidone at elevated temperature. The polymers with inherent viscosities exceeding 0.…
We reexamine the problem of a nematic fluid trapped between two concentric cylinders with different anchoring conditions on each of the cylinders. If the splay constant ${\mathit{K}}_{\mathit{s}}$ is less than the bend constant ${\mathit{K}}_{\mathit{b}}$, the director varies monotonically between the plates. If, howe…
ADVERTISEMENT RETURN TO ISSUEPREVArticleRole of Entanglements on the Fracture Toughness of Incompatible Polymer InterfacesV. Janarthanan, Richard S. Stein, and Paul D. GarrettCite this: Macromolecules 1994, 27, 17, 4855–4858Publication Date (Print):August 1, 1994Publication History Published online1 May 2002Published…
We investigate the moiré fringe pattern of two concentric-circle gratings with the aim of measuring the relative two-dimensional planar displacement induced between the gratings. In the first stage we give a comprehensive mathematical approach for the analysis of fringe patterns. Then we suggest a fast computational m…
We present the first small angle neutron scattering studies on liquid crystal polymer composite systems, where small amounts of polymers are dispersed in liquid crystals. A recent study (A. Jákli, D. R. Kim, L. C. Chien and A. Saupe, 1992, Appl. Phys. 72, 3161) showed that even 1 wt% of polymer can induce phase separa…
Abstract In this paper, scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and wide‐angle X‐ray diffraction (WAXD) were used to study the structure and compatibilization of poly(propylene) (PP)/nylon‐12 (PA 12) blends. The compatibilization of maleated PP(PP‐MA) and graft copolymer (PP‐MA‐ g ‐…
The chemical and physical properties of AgelessR oxygen absorber, a commercial oxygen scavenger, are described. The active ingredient in Ageless is finely divided iron, but the key to its use as a practical method of removing oxygen is the method of preparation, additives and packaging. Criteria for museum use are put…
Deposition of silicon from chlorosilanes is studied. Based on a model for gas‐phase reactions involving , , , and , the reaction constants for relevant gas‐phase reactions are determined. Deposition is analyzed in two ways: one (effusive flux model) using the surface reaction probabilities of surface reactions, and th…
An optical band-gap shrinkage was found in highly transparent and conducting thin films deposited by the Pyrosol process. The narrowing appears at carrier concentrations which are consistent with a metal-semiconductor transition. The gap-shrinkage dependence on carrier concentration is consistent with the model propos…
Current studies on the fatigue lifetime of ceramics are mostly focused on the relation between the stress amplitude (or maximum Stress) and cycles to failure. For a more compliant and plastic ceramic which has a pronounced nonlinear stress–strain relation, the role of plastic strain in the fatigue damage is investigat…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAccurate Mixture-Model Densities for D2OMary Vedamuthu, Surjit Singh, and G. Wilse RobinsonCite this: J. Phys. Chem. 1994, 98, 34, 8591–8593Publication Date (Print):August 1, 1994Publication History Published online1 May 2002Published inissue 1 August 1994https://pubs.acs.or…
In Parts I and II, we reported that during nonsteady-state transport of water vapor through layered fabrics, the temperature between two fabrics rose. In this study, we measure the surface temperature of the first-layer fabrics in similar experiments. The mass of the first layer is changed by tightly stacking the same…
A high density polyethylene homopolymer was blended with a linear low density ethylene hexene copolymer over the composition range of 0–100%. The resistance to slow crack growth was measured by a notched tensile test under constant load at 42, 60 and 80°C. The morphology was varied by slow cooling, quenching and annea…
Abstract Crystallinities of films of copolymers of chlorotrifluoroethylene with 0 to 4% vinylidene fluoride, different molecular weights and thermal histories were calculated from differential scanning calorimetry (DSC), X‐ray diffraction (XRD), and density measurements. The crystallinities for these films range betwe…
A detailed electrochemical evaluation of Sn‐modified LaNi 5 was performed to evaluate its performance as a negative electrode in alkaline rechargeable cells. Substituting small amounts of Sn for Ni provides a large improvement in the initial capacity and cycle lifetime of the electrode, and also serves to improve the…
An experimental set-up designed for in situ Raman analysis during the growth of diamond films in a microwave plasma reactor is described. A gated multichannel detection synchronized with a pulsed YAG laser is used to discriminate the Raman signals from the plasma emission. The in situ detection of a diamond film durin…
Gallium is a metal that literally melts in your hand. It has low toxicity, near-zero vapor pressure, and a viscosity similar to water. Despite possessing a surface tension larger than any other liquid (near room temperature), gallium can form nonspherical ...Read More
ABSTRACT: Theoretical and experimental evidence for the occurrence of multiple relaxation regimes in polymers far above the glass transition temperature is presented and interpreted in terms of the Kohlrausch-Williams-Watts (KWW) stretched exponential expression. Intramolecular effects responsible for the observation…
Vibrational Raman spectroscopy was used successfully for the quantitative determination of the cubic and monoclinic phases of zirconia. Pressed pellets with known composition were prepared using monoclinic and cubic powders from different manufacturers and were used as standard mixtures. An intensity ratio plot of the…