Materials Literature
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Revue portant sur les applications de ces alliages a solidification rapide a partir des feuilles metalliques amorphes pour dispositifs magnetiques jusqu'aux composants consolides par metallurgie des poudres pour applications structurales; on passe aussi en revue les modeles mathematiques appropries au processus de sol…
A comprehensive summary is provided on the subject of heavy metal fluoride glasses. This includes discussions on glass compositions, preparation, structure, fiber drawing characteristics, and intrinsic and extrinsic optical properties. Other relevant glass and fiber characteristics such as strength, durability, and th…
XPS techniques have been used to characterize electrically conducting films of polypyrrole and polybithiophenes as grown electrochemically. These techniques have yielded information not only on the nature of the polymeric cation and its counter anion but also on the structural disorder in these polymers. In particular…
Abstract The structure and chemistry of thin solid films are best studied by transmission electron microscopy (TEM) when they are viewed in cross‐section—that is, when the surface normal of the film is made perpendicular to the electron beam. In this orientation, the substrate, the thin film layers, and the interfaces…
Hitherto unobtainable Raman solution data for [Ru3(CO)12], [Os3(CO)12], and [Ru4H4(CO)12] in the carbonyl stretching region are presented. The results were obtained by careful choice of solvent and specialist instrumentation. They are shown to confirm previous assignments, by examining the special vibrational properti…
We consider a lattice dynamics model of a straight screw dislocation moving in a simple cubic lattice with nearest-neighbour « snapping bonds ». The effect on the lattice of the dislocation motion is described by a dynamic source-force, or Kanzaki-force, and the lattice response by the phonon Green's function. A rando…
The first molecular weight determination for a pyrrole based conducting polymer indicates that poly(β,β′-dimethylpyrrole) consists of chains of up to ca. 1000 pyrrole units.
Soluble conducting poly(acetylene)–poly(isoprene) block copolymers have been synthesized by using the polymeric catalyst formed by the reaction of poly(isoprenyl-lithium) with tetrabutoxytitanium in toluene at room temperature; an instantaneous polymerization of acetylene is observed leading to the formation of a bloc…
Novel heterocyclic systems in which a porphyrin pyrrole has been ring-expanded to a morpholine derivative (5), ring-contracted to an azetine derivative (6), and converted into the oxazolone derivatives (4) and (9) result from selective oxidation of 2-amino-5,10,15,20-tetraphenylporphyrin (1).
Germs of cholesteric liquids were studied in classical mixtures of nematic compounds (MBBA, PAA) with a twisting substance (cholesterol benzoate). These germs were also studied with different polymers of biological interest : synthetic polypeptides (PBLG), nucleic acids (DNA) and polysaccharides (xanthan). Germs are e…
Nickel oxides characterised by electron microscopy and with different defect concentrations have been studied by X-ray photoelectron spectroscopy. Oxides preannealed in air at 700, 1100 and 1450 °C were examined after heating in vacuo in the spectrometer between 20 and 500 °C. High-binding-energy components of O(1s) s…
We propose and investigate the properties of a model of pattern formation in crystal growth. The principal dynamical variables in this model are the curvature of the solidification front and the thickness (or heat content) of a thermal boundary layer, both taken to be functions of position along the interface. This mo…
ABSTRACT AN experimental dryer was designed and fabricated for thin layer drying studies of pecans. Thin layer drying data were obtained for in-shell pecans for 16 drying conditions involving four dry bulb temperatures (29.4, 35.0, 40.5 and 46.1 C) and four dew point temperatures (8.9, 13.3, 17.8 and 22.2 C). Four mat…
Abstract The thermodynamic properties of isotactic polypropylene in the fully crystalline, glassy, and molten state are established from 0 to 500 K based on data bank heat capacities and the vibrational frequency spectrum. The seven skeletal vibrations are described by θ 3 and θ 1 of 91 and 714 K for crystalline polyp…
Abstract
The development of texture and plastic anisotropy (γ-value) during the annealing of low-carbon steel is described. The effects of various industrial processing parameters are considered as well as effects of steel chemistry and microstructure. Comparison is made of box-annealing and continuous annealing technologies.
Tribology in metalworking: friction, lubrication, and wear , Tribology in metalworking: friction, lubrication, and wear , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی
During the last few decades fluorescence spectroscopy has developed into an important and widely used technique in the physical, chemical, and biological sciences. The increasing sophistication of theory and methodology has permitted us to apply fluorescence techniques profitably to a variety of complex problems. A fu…
We have studied Raman scattering from 〈100〉 GaAs samples implanted with 270-keV As+ ions with various fluences up to 3.2×1014 cm−2. In addition to phonon density of states effects, we observe a softening and asymmetric broadening of the allowed LO phonon while the small symmetry forbidden TO phonon remains almost unch…
In any particular clay stratum the ratio of the plasticity index to the clay fraction content is approximately constant, and may be defined as the “activity” of the clay. Values of activity are given for many clays and also for the more common minerals. It is shown that activity is related to the mineralogy and geolog…