Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
The kinetics of adsorption and desorption of carbon monoxide on Ir(111) have been investigated using the well-defined and carefully calibrated IR absorption peak position of the CO intramolecular stretching vibration as a nonintrusive coverage probe. Experiments were performed with time-resolved Fourier transform infr…
Fire resistant sheet moulding compounds based on biofibre-glass hybrid reinforcements were developed and the efficacy of the fire retardancy was determined by the measurement of the limiting oxygen index and the results were correlated with the differential scanning colorimetric data.
A hydrogenation-disproportionation-desorption-recombination process (HDDR) was applied to Sm2Fe17−xGax (x=0.5, 1, and 2). The process was studied by means of temperature-pressure analysis, x-ray diffraction and scanning electron microscopy. It was shown that Ga not only stabilizes the interstitially modified compounds…
Abstract— A reaction sintering route is developed to produce, “in situ”, composites of alumina‐aluminium titanate using alumina and titania as starting powders. Aluminium titanate, can be formed by a solid state reaction between Al 2 O 3 and TiO 2 at temperatures above the eutectoid temperature of 1280°C. These compos…
Abstract Perpendicularly-linked pentamethinestreptocyanine dimers (1) in which the two cyanine moieties are linked at the center carbon atoms of the methine chains were prepared. The absorption spectra of 1 in solution showed two peaks at 446 and 406 nm, which are attributed to the splitting of the HOMO levels through…
The chemical and magnetic structures of neodymium/praseodymium superlattices grown by molecular-beam epitaxy have been determined using x-ray and neutron-diffraction techniques. The x-ray measurements show that the superlattices have a dhcp structure of high crystalline quality, and that the stacking sequence is coher…
Novel biphotochromic systems containing two norbornadiene moieties in one molecule or one norbornadienyl group in 2-N-(3-phenylnorbornadiene-2-carbonyl)]-N-arylaminomethylene-(2H) benzo[b]thiophenones have been prepared. Under UV/VIS irradiation the latter compounds undergo Z/E-isomerktion acompanied by N → O acyl rea…
Abstract The photoisomerization of trans ‐10b,10c‐dimethyl‐10b,10c‐dihydropyrene ( 1 ), its 2,7‐di‐ tert ‐butyl derivative 5 and a series of potassium sulfonate derivatives of 1 , in both [D 8 ]1,4‐dioxane and [D 2 ]dichloromethane as solvent, has been studied using λ = 420–570 nm irradiation. Irradiation of a deoxyge…
An investigation was made of the effect of the nature of elastomer, thickness of the membrane and its formulation, and the temperature and relative humidity of the surroundings, on the permeation of bis(2-chloroethyl)sulfide (SM), a well-known chemical warfare agent, through solution-cast elastomer membranes. The perm…
The difference in heat capacity of the LI2 and hP24 phases of Co3V was measured by calorimetry at temperatures from 80 to 320 K. Inelastic neutron scattering measurements were performed on Co3V with the LI2, hP24 and fcc phases at elevated temperatures, and the neutron-energy-loss spectra were converted into phonon de…
The higher order kinoform lens is a diffractive imaging lens for which the optical path length transitions between neighboring zones is an integral multiple of the design wavelength. Convenient expressions for diffraction efficiency, Seidel aberrations, and spherical aberrations of different orders are derived. It is…
The reactions of YCl3 with the polyalcohols (HOCH2)3CCH3 and (HOCH2)3CN(CH2CH2OH)2 in MeOH yielded [Y{(HOCH2-O3CCH3}2Cl2]Cl·MeOH (1) and [Y{(HOCH2)3CN(CH2CH2OH)2}Cl2(MeOH)]Cl (2), respectively. Similarly, the reaction of Y(NO3)3 with (HOCH2)3CCH3 in ethanol gave [Y{(HOCH2)3CCH3}Cl2(NO3)2 (3). In all cases, the ligands…
Important perfumery aldehydes such as 10-undecenal could be synthesized by Rosenmund reduction. This reduction by hydrogen is usually effected in the presence of a supported Pd catalyst. The main by-product is the alcohol, and it is formed by the subsequent reduction of the aldehyde. This can be prevented by the use o…
Abstract Hexamethyltiisilizane (HMDS) is an excellent method of chemical drying of hydrated specimens. There are several variables involved in its use, the most easily controlled being the number of transitional steps from 100% eihanol (EtOH) to 100% HMDS and the drying temperature. Fixation and dehydration are the sa…
Soils in the northwestern region of Rwanda developed from volcanic materials that originated from eruptions of six volcanoes during the Quaternary period. This study assessed primarily soil morphological, chemical, and physical property differences along a toposequence on the slopes of these volcanoes. Three represent…
Abstract Poly[ p ‐(4′‐cyanobiphenyl‐4‐yloxymethyl)styrene]s ( PCBMS ) were prepared by chemical modification of poly( p ‐chloromethylstyrene) with the sodium salt of 4‐cyano‐4′‐hydroxybiphenyl or free radical polymerization of p ‐(4′‐cyanobiphenyl‐4‐yloxymethyl)‐styrene ( CBMS ). The latter method appeared to be a goo…
We present a new molecular-level picture of chain dynamics for describing the viscoelasticity of crosslinked polymers. The associated mathematical model consists of a time-dependent momentum balance on a representative polymer segment in the crosslinked network, plus phenomenological expressions for forces acting on t…
Abstract As potential nonlinear optical material. 12‐nitro‐4,7‐bis(2‐ferrocenylvinyl)[2.2]paracyclophane ( 1 ) and 12‐nitro‐4,5,7,8‐tetrakis(2‐ferrocenylvinyl)[2.2]paracyclophane( 2 ) have been synthesized by pd‐catalyzed coupling reactions of vinylferrocene with the precursor cyclophanes 9 and 13 , respectively. The…
Tests were conducted on two fabrics intended for use in protective clothing: an aramid (used extensively in firefighter gear) and a modified viscose cellulosic fabric. Both were exposed to very high heat (temperatures above 400°C) and their performance as thermal insulators was assessed by the temperature transmitted…
We have studied end-linked polystyrene networks containing labeled (deuterated) free chains subjected to an uniaxial deformation using small-angle neutron scattering (SANS). The networks are made by end-linking protonated polystyrene precursor chains of a narrow size distribution. As for statistical networks investiga…