Materials Literature
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Biodegradable films were prepared by casting acetone solutions of mixtures of a high molecular weight poly(DL-lactic acid) (HMW-PLA50) with 0, 10, and 30% w/w poly(DL-lactic acid) oligomers (LMW-PLA50), before drying. From size exclusion chromatography (SEC) it was shown that degradation occurred during film processin…
Bacillus subtilis has duplicate isochorismate synthase genes, menF and dhbC. Isochorismate synthase is involved in the biosynthesis of both the respiratory chain component menaquinone (MK) and the siderophore 2,3-dihydroxybenzoate (DHB). Several menF and dhbC deletion mutants were constructed to identify the contribut…
A new poly(L-)lactic acid (PLLA) thread was tested by applying it in fascial closures of male Wistar rats. The tissue reactions around the thread and in the fascial union, and the changes on the surface and the mechanical properties of the thread were evaluated at 1, 3, 6, 12, 28, and 52 weeks following surgery. Histo…
Serpentinite from Lancaster County, Pennsylvania, consists of a variety of fme-grained serpentine minerals, chlorite, randomly interstratified serpentine-chlorite, and a series of phases based on regular interstratification of serpentine and chlorite (SxCy, where x and y are integers). Within the resolution of the AEM…
X-ray absorption spectroscopy is widely employed in the structural analysis of disordered systems. In the standard extended x-ray absorption fine structure (EXAFS) analysis the coordination of the photoabsorber is usually defined by means of Gaussian shells. It is known that this procedure can lead to significant erro…
Abstract The general crystallization behavior of amorphous polyamides during heating treatment was measured by wide angle X‐ray scattering (WAXS) and differential scanning calorimetry (DSC) to get information on (1) the temperature range where the crystallization in an anisothermic process takes place and (2) the type…
Application of a microwave dissolution technique for plant tissues using hydrofluoric acid (HF), nitric acid (HNO3), and hydrogen peroxide (H2O2) as reagents was studied. It was found that the use of all reagents in the mixture followed by the microwave heating in many cases does not lead to complete dissolution. The…
We demonstrate a spherical diffractive lens fabricated in fused quartz for use at the 632.8-nm wavelength. The lens is constructed by use of a modulated two-dimensional binary grating with a high transmitted zerothorder efficiency. Rigorous eigenmode analysis is used to correlate the desired phase modulation with the…
Melt-textured (Y123) containing fine particles of (Y211) has been prepared from Y123/Y211 powder that was attrition milled with 1 wt% addition, and the microstructure has been examined. Fine and spherical Y211 particles (less than 1 m in size) are found to be homogeneously dispersed within the melt-textured Y123 domai…
Two types of novel aromatic copolyesters were synthesized from 11-phenoxyundecanoic acid (11-POU) as the sole carbon source and the cosubstrates 11-POU and octanoate, respectively, by isolated Pseudomonas putida BM01 that is known to accumulate high concentrations of medium-chain-length polyesters. Insoluble 11-POU wa…
A new technique for synthesizing small batches of oxide-based ceramic and glass materials from high purity powders is described. The method uses continuous wave CO2 laser beam heating of material held on a water-cooled copper hearth. Contamination which would normally result during crucible melting is eliminated. Deta…
The local magnetic moments and hyperfine fields, the intersublattice exchange fields, the electric field gradients, and the crystal field parameters are calculated for the technologically important hard-magnetic compound ${\mathrm{Nd}}_{2}$${\mathrm{Fe}}_{14}$B by the full-potential linear-muffin-tin-orbital method in…
Lamivudine can be obtained as acicular crystals (form I, 0.2 hydrate) from water or methanol and as bipyramidal crystals (form II, nonsolvated) from many nonaqueous solvents. Form II is thermodynamically favored in the solid state (higher melting point and greater density than form I) at ambient relative humidities. S…
Abstract Blends of polypropylene (PP), the triblock copolymer polystyrene‐ block ‐poly(ethylene‐ stat ‐butylene)‐ block ‐polystyrene (SEBS), and processing oil were found to form thermoplastic interpenetrating polymer network (IPN) structures in a composition range from about 10 to 55% by weight polypropylene. The IPN…
The temperature dependence of the dc conductivity of electrochemically polymerized films of polypyrrole, poly(N-methyl pyrrole) and their copolymers, poly(N-methyl pyrrole-pyrrole), having different percentage of BF−4 ions has been investigated in the temperature range 77–350 K. The observed behavior could be explaine…
Abstract Helvetic sediments from the northern margin of the Alps in eastern Switzerland were studied by clay mineralogical methods. Based on illite “crystallinity” (Kübier index), the study area is divided into diagenetic zone, anchizone and epizone. Data on the regional distribution of the following index minerals ar…
Aims to evaluate the effectiveness of 2‐amino 4‐phenyl thiazde (APT) and its three anils as inhibitors for the corrosion of mild steel in 1M HCl. Discusses the variation of inhibition efficiency with temperature. Gives account of experimental procedures on mild steel strips for weight loss measurements and potentiodyn…
The anodic polarization behavior of copper in 1 M NaI at ∼24°C was compared with calculations based on thermodynamic equilibria and shown to be consistent with the potential‐pH diagram for the system. An active region was predicted and observed where cuprous complexes, , are formed. The active region exhibited a Tafel…
Freshly produced red, yellow and green emitting porous Si specimens have been studied by NEXAFS and EXAFS (near edge and extended x-ray absorption fine structure). The emission peaks are at 690, 580, and 520 nm, which almost covers the full visible range that direct anodization can achieve. The correlation between the…
The electrochemical behavior of hydrated manganese‐substituted nickel hydroxides in Ni/Cd cells was studied. Partial substitution of manganese for nickel was shown to induce stabilization of the discharge capacity during long‐term cycling. Such behavior is related to the very small discrepancy between the interslab di…