Materials Literature
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The mechanical properties of polymers are strongly influenced not only by the structure of the material but by the magnitude of the molecular orientation. Thus a great deal of interest exists in information about the molecular orientation in samples introduced by drawing or other forming processes. Several techniques…
Abstract Based on experimental data, changes of properties of plasticized PVC containing stearates of Ca, Zn, Cd, and Pb stabilizers during thermal degradation are discussed. The mechanism of action of these stabilizers is described in kinetic form.
K2SnBr 6 at room temperature, monoclinic, P2~/n, a = 10.621 (2), b = 7.427 (2), c = 7.442 (2) fi~, fl = 90.18 (2) °, D x = 3.825 Mg m -3 for Z = 2. The crystal structure is a distorted KEPtCI 6 structure. The
Published information on the performance of 90/10 copper-nickel-iron alloy in sea water environments is reviewed, covering the effect of iron content and of different heat treatments, behaviour in quiescent sea water and in polluted sea water, resistance to impingement attack (effect of water velocity), crevice corros…
Photoemission spectroscopy (u.p.s. and X.p.s.) and Auger Spectroscopy (X-ray induced) have been used to study the oxidation of clean evaporated zinc films. At 300 K, two oxygen species coexist throughout the adsorption process. The major species [O(1s) b.e. 530.0 eV] is characteristic of oxide and is considered repres…
Craig E. Williamson, An Ultrastructural Investigation of Algal Symbiosis in White and Green Spongilla lacustris (L.) (Porifera: Spongillidae), Transactions of the American Microscopical Society, Vol. 98, No. 1 (Jan., 1979), pp. 59-77
AbstractCorrosion trials have been carried out using cast nickel aluminium bronze alloy in the as cast, heat treated and welded states, and the specimens examined using optical and electron optical techniques. It has been shown that selective phase corrosion can occur near the heat affected zone of welded cast nickel…
The recrystallization textures of copper and different Cu‐Zn alloys as well as the rolling and recrystallization textures of silver of varying purity were investigated as a function of the rolling temperature. In all cases in which the pure copper type rolling texture was present the cube texture was found as recrysta…
A transmission electron microscope (TEM) was used to study the neutron irradiation-induced defect structures in zirconium from various sources irradiated to fluences up to 1.3 × 1025 neutrons (n)/m-2 > 0.1 MeV and temperatures in the range 478 to 823 K. Below 673 K the predominant form of damage consists of ⅓ 〈…
The number and properties of carbamyl phosphate synthetases in Bacillus subtilis have been uncertain because of conflicting genetic results and instability of the enzyme in extracts. The discovery of a previously unrecognized requirement of B. subtilis carbamyl phosphate synthetases for a high concentration of potassi…
L'étude de la conductivité alternative σ(ω) des chalcogénures massifs non cristallins (Se, As2S3, As2Se 3, (As2Te3)1-xGex, Se 1-xGex) a été effectuée dans de grands domaines de fréquence (1 kHz-35 GHz) et de température (100-300 K). Deux effets de contact, l'un observable aux basses fréquences et l'autre au-dessus de…
The paper presents an analysis of WAXS (wide-angle X-ray scattering) data which aids an understanding of the structure of non-crystalline polymers. Experimental results are compared with calculations of scattering from possible models. Evidence is presented which supports the view that the chains in molten PE do not l…
Pressure–composition–temperature relationships are presented for the titanium–cobalt + hydrogen and the titanium–nickel + hydrogen systems for the ranges 10 kPa to 2 MPa and 325 to 600 K. The TiCo + H system exhibits three distinct two-phase regions, whereas the TiNi + H system contains no two-phase regions in this ra…
In this review the authors cover both the scientific and practical aspects of the metallurgy of galvanized coatings. They begin the review by considering the current iron—zinc equilibrium phase diagram; special emphasis is placed on the correlation between the actual phases found in galvanized coatings and those which…
Specimens of 99·9 %purity copper were deformed initially by torsion up to €=200. Their mechanical properties were determined from tensile tests. The extreme values of mechanical properties were observed in a range of strain €=3−200. Changes in microstructure reflecting the mechanicalproperties of the specimens were in…
The occurrence and stereochemistry of a rapid reversible C–H fission in [[graphic omitted]But2)] is established by n.m.r. spectroscopy, including triple resonance INDOR, and by X-ray crystallography.
It has been demonstrated that self‐concentration quenching mechanisms can be determined from luminescence intensity measurements as a function of activator concentration if the excitation of a powdered phosphor screen is made with the directly and weakly absorbed radiation.
Casting alloys of eutectic composition are of great practical importance. Good microstructural control of these alloys is essential in obtaining the required properties in the cast state. Primary phases present in a eutectic matrix may have either a beneficial or a detrimental effect on these properties. Therefore, th…
Characteristic features of isothermal growth, thickening and melting behaviour of melt grown single crystals of low molecular weight poly(ethylene oxide) fractions are described and discussed in terms of their relevance to basic concepts of polymer crystal growth. In the narrow temperature interval where transition fr…
УСПЕХИ ФИЗИЧЕСКИХ Η Λ У К 535.44 ОПТИКА ХОЛЕСТЕРИЧЕСКИХ ЖИДКИХ КРИСТАЛЛОВ В. А. Беляков, В, Е. Дмитриеико, В. П. Орлов СОДЕРЖАНИЕ 1. Введение 221 2. Кинематическое рассмотрение 224 а) Сечение рассеяния (225).б) Поляризационные характеристики (226).3. Случай нормального падения 227 а) Собственные волны (227).б) Решение…