Materials Literature
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Valence and conduction state distributions in a series of Al-Cu-Fe and Al-Cu-Fe-Cr alloys of different structural states and nominal compositions have been investigated by means of soft X-ray emission and photoabsorption spectroscopies. A complete description of the valence band is obtained. The DOS at E F is observed…
The alpha - beta , beta - gamma and gamma - delta transitions in Na 2 CO 3 are observed through frequency changes in the carbonate ion internal modes. The incommensurate phase shows particularly interesting behaviour, as the nu 4 mode splits into two components at the beta - gamma transition which represent edge singu…
The electron-energy distribution in a gold film was measured with \ensuremath{\sim}700 fs time-resolved photoemission spectroscopy following laser heating by a 400 fs visible laser pulse. The measured distribution can be fitted by the Fermi-Dirac function at an elevated temperature except within 800 fs of the heating…
The electronic structure for graphene monolayer tubules is predicted as a function of the diameter and helicity of the constituent graphene tubules. The calculated results show that approximately 1/3 of these tubules are a one-dimensional metal which is stable against a Peierls distortion, and the other 2/3 are one-di…
A guide to the properties and uses of the different alginate dressings available today.
Article Re-Investigation of the Gd - Co Binary System / Untersuchungen im binären System Gd —- Co was published on May 1, 1992 in the journal International Journal of Materials Research (volume 83, issue 5).
Navicula geisslerae sp. nov. is described from the river Spree on the basis of LM, TEM and SEM studies. N. geisslerae is compared with similar taxa, e.g. N. absoluta Hustedt, and its generic status in relation to the species previously placed in sub-genera of Navicula are discussed.
The effect of vanadium (0–4%) on the morphology and amount of eutectic and eutectoid carbides in high speed steels has been investigated using scanning electron microscopy and image analysis. It was found that vanadium promotes the formation of MC carbide and M2C carbide, but inhibits the formation of M6C carbide. In…
During recent years, various hydantoin based heterocyclic glycidyl amine resins have been developed. In these resins the presence of nitrogen containing heterocycle provides extensive variation in polarity, viscosity and hydrophobicity by the choice of alkyl groups. Most of these resins have low viscosity, high polari…
This paper discusses the use of Rietveld analysis to solve crystal structures of titanyl phthalocyanines. Rietveld analysis is based on whole pattern fitting in which every point in the x-ray powder diffraction pattern is used as a measure of one or more Bragg diffraction peaks. Thus the refinement of relatively compl…
It is shown that fatty acids such as the arrachidic and the lauric acids and their mixtures with cholesterol exhibit nonlinear optical properties. The effects of a 20 mW He-Ne laser (λ= 6328 Å) on such mixtures exhibiting smectogenic mesomorphism were examined and the optical activity dependence on the cholesterol per…
Heat capacities and thermodynamic properties of a number of poly(chlorotrifluoToethylene) samples subjected to various thermal treatments, to achieve crystallinities ranging from approximately 10 to 90%, have been studied from 2.5 to 370 K by automated adiabatic calorimetiy and from 250 to 620 K by differential scanni…
Abstract Three of the six possible stereoisomers of dodecahydroacenaphthylene, t,t,t ‐ufolane ( 1 ), c,c,t ‐ufolane ( 3 ), and c,c,c ‐ufolane ( 5 ), have been synthesized for the first time. The configurations have been confirmed inter alia by an X‐ray analysis of the precursors 11, 14 , and 23 and the bromine adduct…
In situ observation of the growth of isotactic polystyrene has been carried out under a transmission electron microscope. Bundles of lamellar crystals first emerge from the melt, and then a planar crystal parallel to (001) grows out from one end of each bundle. The planar crystal assumes the shape of a hexagon faceted…
Backscattering of radiation incident on a solid medium has been treated with some success as a reflection phenomenon. The concept of albedo has been used in the literature to deal with this problem. A Monte Carlo program has been used in this study to simulate the generation of bremsstrahlung beams from medical linear…
Some effective uses of the radial gradient-index (GRIN) lens in zoom lens systems are presented and lens design examples are shown. Also the effective Abbe number of a cemented GRIN lens is discussed and it is shown that a radial GRIN lens with uncommon dispersion can be replaced by a cemented radial GRIN lens with co…
Abstract Understanding the dynamics of soil K is important for the formulation of a sound fertilizer management strategy. Two experiments were conducted to determine the behavior of K in the soil after fertilization. Five rates of K (0 to 120 kg ha −1 ) were applied to two Typic Paleudults, a loam and a sandy loam, in…
Fouling cannot always be prevented; it is important to consider the design of fouling‐resistant heat exchangers. To examine these exchangers, a test fluid whose fouling behaviour is understood should be used. Experiments have been conducted to examine the response of two model systems, a pulsatile flow and a fluid bed…
Abstract Amorphous Nb 2 O 5 thin films are obtained by vacuum evaporation of high‐purity Nb 2 O 5 powders onto NESA glass substrates. These films were found to exhibit both photochromism and electrochromism. Reasonably good photochromic responses were observed in ethanol and in the N 2 atmosphere, but no photochromism…
The synthesis and nonlinear optical properties of a series of chiral pyrrolo[1,2-a]quinolines la-e is presented. The microscopic hyperpolarizabilities (beta(z)) were determined by EFISH measurements and the macroscopic susceptibilities (X2) were estimated by the Kurtz powder test. A small fixed angle of the annelated…