Materials Literature
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While the As-rich 2 × 4 reconstruction of GaAs(001) is well explained by the so-called β 2 structure, the atomic structure of the Ga-rich 4 × 2 phase has been discussed for a long time. In this review, the most important structural models for the GaAs(001) (4 × 2)/c(8 × 2) surface are compared from different theoretic…
Abstract Six organic volatile corrosion inhibitors (VCI) were synthesized using lauric hydrazide with various acids such as cinnamic acid, succinic acid, nitrobenzoic acid, phthalic acid, and maleic acid and evaluated as corrosion inhibitors of mild steel, copper, brass, zinc, and aluminum by weight loss and potentiod…
The formation mechanism of ZrSiO 4 in the cordierite‐ZrO 2 system was studied in the temperature range of 1250° to 1400°C by X‐ray diffraction analysis and discussed by analyzing experimental data using some reported reaction models. Nuclei growth models were found to describe the reaction well, and a satisfactory fit…
Non-chromate conversion films are formed on the surface of an Al-Z n-Mg-Cu alloy using a two step cerium salt treatment. The corrosion resistance of the alloy in chloride solution has been studied after the non-chromate treatment. It was found that the conversion film could greatly improve the corrosion resistance of…
We apply the boundary element method to the analysis of optical waveguides. After summarizing constant and linear element algorithms for both two- and three-dimensional simulations, we introduce a new recursive series procedure for constructing the diagonal matrix elements. We then demonstrate that our method can be e…
Author: Graat, P. C. J. et al.; Genre: Journal Article; Issued: 2002-06; Keywords: MPI für Metallforschung; Abt. Mittemeijer; 30-mi_2002; iron; iron nitride; oxidation; nitrogen; Title: On the kinetics of the initial oxidation of iron and iron nitride
Conductivity of Porous Silicon (PS) can be modulated significantly by controlling its formation parameters like anodization current density and HF concentration in the electro-chemical cell and the doping concentration of the silicon wafer. It is established that not only the porosity but also the uniformity of the PS…
Abstract The structure of a natural sample of chondrodite (Mg 4.89 Fe 0.07 Si 2.04 O 8 F 1.54 (OH) 0.46 ) was refined using powder neutron diffraction data and the Rietveld technique ( P 2 1 / b ; Z = 2; a = 4.7204(1)Å; b = 10.2360(3)Å; c = 7.8252(2)Å; α = 109.11(1)°; V = 357.26(2)Å 3 ). Hydrogen was found to occupy t…
Composition ( x )-temperature ( T ) phase diagrams obtained for the first time for single-crystalline (Na,Li)NbO 3 (system I) and (Na,K)NbO 3 (system II) niobates are compared with the known phase diagrams for ferroelectric niobate ceramics prepared by various techniques (standard firing and hot pressing). In system I…
Abstract The thermal property of HA/water solution was studied from the calorimetric data obtained using differential thermal analysis (DTA). The intensity of decomposition was studied from results of a mini closed pressure vessel test (MCPVT), and a pressure vessel test (PVT), in addition to the steel tube test. The…
In this paper, we describe variations in a boehmite (AlOOH) and oleic acid emulsion during the process of forming superfine α‐Al 2 O 3 crystallites from the mixture of oleic acid and a boehmite gel precursor. We also propose that the oleic acid decomposes under calcination, generating carbon, which can effectively pre…
Cluster calculations of the local adiabatic potential for an impurity atom in position A in Sr 1− x A x TiO 3 ( A =Mg, Ca, Ba, Pb, Cd, Zn), as well as for the Nb and O atoms in the Ta-O-Nb chain in KTa 1− x Nb x O 3 , were carried out in the nonempirical Hartree-Fock-Roothaan MO-LCAO formalism. For comparison, similar…
The synthesis, characterization and crystal structures of substituted imidazolate bridged binuclear copper(II) complexes, [Cu2(dien)2(L)](ClO4)3, where dien = diethylenetriamine, L = imidazolate (im—) (1), 2-methylimidazolate (mim—) (2) and benzimidazolate (bim—) (3), are reported. The copper(II) ions of 1—3 posses a…
As a part of an advanced volume reduction program for low level radioactive wastes in JAERI, melting tests of non-metallic solid wastes have been conducted with the aim of establishing the optimum melting condition for preparation of a stable solid that is suitable for disposal. Simulated non-metallic wastes containin…
V2O3 room and low temperature structures have been refined using PXRD and Rietveld procedures. At 15 K, in addition to the umbrella like opening of V—O bonds associated to the typical large V—V distance through the face shared octahedra (V—Vfsh) we have observed three different V—V distances through the edge shared oc…
The objective of this study was to establish the mechanism(s) controlling degradation of yttria‐tetragonally‐stabilized zirconia (Y‐TZP) powder in aqueous suspensions and determine the significance of this degradation to the aqueous physical chemistry of Y‐TZP. Experiments were performed on commercially available Y‐TZ…
Abstract A series of deeply coloured 5-methylmercapto and 5-dimethylamino substituted tris(2-thienyl)methinium perchlorates has been prepared by the reaction of 2-methylmercapto-5-lithiothiophene with methyl 2-dimetylamino-5-thiophenecarboxylate, bis(2-dimethylamino)ketone, or diethyl carbonate, respectively. The prod…
Abstract A generalized equation was derived to calculate the melting temperatures of homopolymers and copolymers. The Gibbs‐Thomson equation for homopolymers and a modified application to copolymers were derived using the proposed equation. The melting temperature T m 0 in the Flory equation corresponds to the melting…
A micromechanics method is developed for the effective magnetostrictive behavior of magnetostrictive composite materials. Explicit relations for determining the effective magnetostriction of the particulate composites with cubic magnetostrictive crystallites are derived and reduce to the well-known results in the case…
Abstract tert-Butoxy groups were introduced at 2 and 2′-positions of the thiophene rings of a dithienylperfluorocyclopentene to prepare a photochromic compound with a thermal cycloreversion reactivity and a low photocycloreversion quantum yield. The cycloreversion quantum yield was similar to the isopropyl-substituted…