Materials Literature
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Size-quantization effects (short-wavelength shift of the structure and broadening) in low-temperature absorption spectra of PbI 2 and HgI 2 nanocrystals embedded in porous sodium borosilicate glass matrix with pores ranging in size from 2 to 50 nm have been observed and studied. The nanocrystal size was evaluated in t…
Porous silicon was formed using highly phosphorous-diffused n-type silicon. Dislocation generation mechanisms due to the force caused by marked volume expansion at the early stage of porous silicon oxidation and strain generation caused by oxidation are investigated. The height of the step produced by oxidation and th…
Abstract The stability of some heterocyclic poly(amide imide)s in acidic and alkaline medium was compared to the structurally related polyimide and poly(amide imide)s without other heterocyclic groups. All the polymers have high stability in acidic medium. The introduction of additional heterocycles such as 1,3,4‐0xad…
Abstract A high‐performance trifunctional epoxy resin based on the triglycidyl ether of tris (4‐hydroxyphenyl)‐methane (TETM) was synthesized by the condensation of 4‐hydroxybenzaldehyde with phenol followed by epoxidation with epichlorohydrin. The structure of TETM was confirmed by mass spectra, infrared and nuclear…
A new, nickel-based alloy resistant to a very wide range of corrosive media is described. The main alloying additions are chromium and molybdenum; however, the alloy also contains {approximately} 1.6% copper, which significantly enhances its resistance to dilute sulfuric and hydrochloric acids. The safe operating regi…
Single tuyère wear tests of MgO‐C and burnt magnesia bricks were performed to study relations between tuyère characteristics and refractory wear parameters, with emphasis on the wear zone geometry. Either Ar or N 2 was used as injected gas and the test temperature for liquid metal was 1400, 1550 and 1700°C. A bubble e…
A series of fluoromethylene cyanate ester resins have been synthesized and studied as potential low dielectric resins for microelectronics. Physical properties were observed to change with the fluoromethylene segment length in the monomer. The polymer can be formed from a stable oligomer that is thermally converted in…
General methods for the analysis of step‐current measurements on intercalation devices are applied to an aqueous, protonic, tungsten oxide‐based device. Plots of the built‐in potential as a function of the passed charge, , are generated. Methods are demonstrated for extracting a useful indicator of the intercalation l…
Wood-plastic composites (WPCs) were prepared with low-grade wood (simul and mango) using methylmethacrylate (MMA) and butylmethacrylate (BMA) as the impregnating monomers under high-energy ionizing radiation from a Co-60 gamma source. Water absorption of both wood and WPC was studied in a stagnant water bed. Water abs…
An ongoing revolution in the development and implementation of new materials has placed new demands on the ability to join these materials into devices, parts and components, and devices, parts and components into packages, assemblies and structures for both electrical and mechanical applications. Looks at the past su…
Effects of oxidation on mechanical properties have been investigated for Y 2 O 3 /5 vol% SiC nanocomposite. The roomtemperature fracture strength and toughness substantially increased after oxidation around 900–1000°C for 5 h. On the other hand, little improvement was identified for specimens treated in an inert atmos…
This paper summarizes methods conventionally used to prepare thin foil samples of powder materials for transmission electron microscopy (TEM) and introduces another variant, ultramicrotomy, for the preparation of TEM samples of industrial dust powder. The choice of ultramicrotoming in the present work was based on two…
While a single ferroelectric liquid-crystal (FLC) cell with a retardation of half a wave can be used as a switchable polarization rotator with monochromatic light, the variation of its retardation with wavelength results in a significant deterioration in its performance with white light. We show how a broadband respon…
The electron field emission, from silicon tip arrays with layer structures on their surfaces, was investigated. The main task of the study was to enhance field emission. The n–Si–SiO2, n–Si–Cs–SiO2,n–Si–SiO2–Si*–SiO2,n–Si–Si3N4–Si*–SiO2, etc., were among the different prepared layered structures. The thicknesses of di…
The crude dry latex of Calotropis procerapossesses a potent antiinflammatory activity. The antiinflammatory activity of petroleum ether, acetone, methanol and aqueous extracts of dry latex of Calotropis procera was tested in the carrageenan induced rat paw oedema model. All the fractions exhibited antiinflammatory act…
An overview of progress and implications of recent technological advances in mechanochemical processing of ferrites is presented. We discuss the potential for applications of mechanical activation by induced phase transformations and chemical reactions in soft and hard ferrite materials through enhancement of structur…
Micromagnetic Barkhausen emissions have been measured from a number of specimens of Cr-Mo steel in order to study the effects of creep. Creep causes changes in the microstructure of materials as a result of exposure to a high temperature and pressure. Scanning electron micrographs showed that all the specimens were at…
Trimethylamine has been used in the growth of compound semiconductors either through the formation of an adduct, as in trimethylamine allane, or as a possible growth reactant. The kinetics of the gas‐phase decomposition and dominant reaction products relevant to these applications were determined in this study. The mu…
A comprehensive geochemical and palaeobotanical study of the lacustrine sediments of Lake Nôm mejärv from industrialized NE Estonia establishes the links between the nature and intensity of human activities and their impacts on the state and structure of the lake ecosystem. In cores of sediment formed during the last…
A series of compounds LaCr1—xNixO3 (x = 0 to 1) with perovskite structure are synthesized by a citrate process and the crystal structures of these compounds are determined. A phase transition in this series of compounds occurs in the region of x = 0.6 to 0.7. The valence states of chromium and nickel ions in LaCrO3, L…