Materials Literature
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Variations in lamination conditions, such as pressure, temperature, and time, changed the laminated density of multilayered alumina but had no effect on the sintered density. The present results showed that sintering shrinkage values differ with lamination conditions and vary inversely with laminated density. When lam…
A novel experimental technique has been developed that allows the recovery of specimens within which an adiabatic shear band has been grown as the result of a single torsional pulse. The technique uses a new device called the compression-torsion Kolsky bar; this is an adaptation of the classical torsional Kolsky bar i…
This paper presents high-resolution synchrotron X-ray powder diffraction data at 290 K on two Fe-bearing. polycrystalline silicate perovskite samples with approximate compositions (Mg 0.95 Fe 0.05 )SiO 3 synthesized at 25 GPa and 1920 K in a multi-anvil press at different oxygen fugacity conditions. Mössbauer smdies…
Evidence of soil degradation impeding soil tillage and irrigation in cultivated soils in Pakistan is identified, described and represented in a general process of degradation. Based on a chemical analysis of soil characteristics, it is shown that a more general geochemical degradation process may occur in these soils.…
The room temperature IR-and Daman spectra of the different M3RE(PO4)2 (M = K, Rb; RE = La, Eu, Gd) double phosphates were analysed and used to interpret the vibronic side band structure in the photoluminescence spectra.The intraconfigurational 4f-4f electronic transitions in the photoluminescence spectra of the Eu3+ d…
Co-sputtered C-Cu thin film depositions have been performed in the temperature range 80-873 K, the atomic carbon concentration varying from 16% to 96%. To characterize the microstructure of the C-Cu thin films, transmission electron microscopy, extended X-ray absorption fine structure and grazing incidence small angle…
Preface * Part I: Mechanical Properties of Materials: The First Materials (Stone Age and Copper-Stone Age). Fundamental Mechanical Properties of Materials. Mechanisms. The Bronze Age. Alloys and Compounds. Atoms in Motion. The Iron Age. Iron and Steel. Degradations of Materials (Corrosion) * Part II: Electronic Proper…
1H NMR spectra of a series of high-spin (meso-tetraalkylporphyrinato)iron(III) chlorides, [Fe(TRP)Cl] where R = Me, Et, Pr, or (i)Pr, have been measured at various temperatures in CD(2)Cl(2) solution. In the case of the Et, Pr, and (i)Pr complexes, either the methyl or the methylene signal split into two signals with…
The effects of initial particle size on the microstructure of silicon nitride ceramics produced by pressureless sintering have been investigated. The microstructures of the silicon nitride ceramics varied considerably with the size of the initial powder. With decreasing powder size, abnormal grain growth was enhanced,…
The interfacial states in adsorbed PEO layers on silica were probed through the self-exchange of coumarin-tagged chains and native analogues. New evidence for nonequilibrium interfacial behavior is presented, though prior studies supported local equilibrium for adsorbed PEO. Results suggest that entanglements or high…
We study two-dimensional binary mixtures of parallel hard squares as well as of disks. A recent cluster algorithm allows us to establish an entropic demixing transition between a homogeneously packed fluid phase and a demixed phase of a practically close-packed aggregate of large squares surrounded by a fluid of small…
A cotton-bound serine protease inhibitor of elastase (fiber-inhibitor) has been formulated for in vitro evaluation in chronic wound fluid. As a model to understand the properties of the inhibitor in wound dressings, the kinetic profile and in vitro release of the fiber-inhibitor formulation have been examined. The ela…
Structure-property relations in meaoscopic BaTiO3 and PbTiO3 are reviewed from the stand-point of effects of crystallite size on intrinsic behavior using the Landau-Ginzburg-Devonshire formalism. Experimental results based on x-ray diffrdctometry and quantitative calorimetry indicate that the critical crystallite size…
Epitaxial LaNiO3 (LNO) thin films were grown on (001) SrTiO3 substrates by laser molecular-beam epitaxy. The growth process of the LNO films was monitored by in situ reflection high-energy electron diffraction (RHEED). Clear RHEED patterns and the intensity oscillation of RHEED were observed during the epitaxial growt…
Polarized ir spectra of oriented films of α-helical poly(l-alanine) (α-PLA) have been obtained as a function of residual solvent dichloroacetic acid (DCA). The amide A, B, II, and V regions exhibit multiple bands whose structure depends on the residual DCA content, and those associated with the αI-PLA structure have b…
The Rosenburg method has been applied to determine physicochemical properties of at 900–1000°C and oxygen pressures from 0.005 to 0.1 atm. The defect concentration was proportional to , whereas the defect diffusion coefficient was essentially independent of the ambient oxygen pressure. This is interpreted to reflect t…
The local coordination environments of alkali cations (Li + and Na + ) in single- and mixed-alkali silicate glasses have been investigated by using cluster model calculations at the Hartree−Fock/6-31G(d) level. The optimized structural parameters obtained for the model clusters are in good agreement with the observed…
Unidirectional liquid crystal (LC) alignment produced by a polarized ultraviolet-light (UV) exposure was examined using various polyimides (PIs) which consist of different tetracarboxylic dianhydrides and diamines. The photosensitivity and anchoring energy of the LC alignment as a function of UV dosage are summarized…
The laser-induced nonlinear optical response of micellar lyotropic liquid crystals in the nematic and isotropic phases is presented. The Z-scan technique is used to measure the amplitude and the sign of the nonlinear refractive indices of the lyotropic mixture. The amplitude of the nonlinear refractive indices $(\ensu…
Because of their inherent toughness and flexibility, low density, thermal stability, radiation resistance and mechanical strength, aromatic polyimides have excellent potential for use as advanced materials on large space structures. Polyimides were uniaxially and biaxially oriented to further enhance their dimensional…