Materials Literature
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Abstract The effect of the annealing temperature on the structure of unoriented polyamide 6 was studied by swelling in methanol and small‐angle X‐ray scattering. The observed values of mean‐square fluctuations of scattering density can be explained by using a model with an inhomogeneously swelling amorphous phase. An…
Abstract CHClF2 has been found to be effective as a surface treatment agent of SiO2–Al2O3 and Al2O3, as well as chlorofluorocarbons (CFCs) such as CCl2F2 and CClF3, to enhance its catalytic activity and/or activity maintenance for the alkylation of benzene with propene. The CHClF2-treatment may be performed at tempera…
It is proposed in this work, to evaluate experimentally: thermal diffusivity, or, and thermal conductivity, k, of poorly conductive materials. The method selected is based on transient heat conduction in solid media and seeks to determine the conditions under which the power series solution characterizing the transien…
Abstract Conformation of viologen-linked porphyrins (p-PCnV, n=4–7), which are capable of intramolecular electron transfer, was studied by 1H NMR in order to gain insight into the relative geometry of the donor and acceptor during the electron transfer process. The orientation of the viologen with respect to the porph…
Three photographic studies are presented which capture the behaviour of material specimens as they are taken to and beyond their failure point by impact and other loading conditions. One is of a polymer sphere impacting onto a rigid flat surface and depending upon the impact velocity, the sphere can fail in different…
The thermodynamic interaction parameter, χφ, for a low-density polyethylene in p-xylene, ethylbenzene, and n-octane has been determined over a range of segment fraction, φ2, from 0.2 to 0.7 using the melting point depression method. Taking advantage of a unique feature of polyethylene, a new procedure has been propose…
In situ laser deposition was used to fabricate YBa 2 Cu 3 O 6.8 (YBCO) films on amorphous glasses. Yttrium stabilized zirconia (YSZ) and conducting indium-tin-oxide (ITO) were used as the buffer layers to improve the transport properties of YBCO films. There was negligible interdiffusion occurring at the interfaces. Y…
Chemical behavior of nitrogen species in intense radiation fields was studied. Simulation models and a N/H/O reaction scheme were developed and verified with a series of experiments. The following results and suggestions were obtained: 1. Ammonium formation rates in water pressurized with H2 and N2 gases at temperatur…
In order to protect them from environmental degradation, as well as to increase their reflection efficiency in some instances, metallic gratings are often coated with dielectric materials. This practice introduces the effects of waveguide modes in the reflection characteristics. Here, we study the alteration of the pl…
The intermediate phase of the aluminate sodalite Ca8[Al12O24](WO4)2, stable between 653 and 617 K, has been studied by X-ray single crystal, X-ray powder and neutron powder methods, and its structure determined. The phase is difficult to detect by diffraction methods, mainly because of its similarity with the cubic ph…
Comparative analysis of main optical characteristics of KDP crystals grown by traditional technique at growth rates up to 1 mm/day and by rapid growth technique at growth rates ranging from 15 to 40 mm/day is carried out. The results on anomalous biaxiality absorption ard scattering of light effective nonlinear suscep…
ABSTRACT The influence of ternary solvent composition on mass adsorbed and on surface forces between adsorbed polystyrene layers was investigated. Polystyrene (M, = 500 000 and 3.84 X lo6) was adsorbed onto silicon oxide and mica from dilute solution (0.15 mg mL-1) in mixtures of cyclopentane and n-pentane at 23 OC. S…
A photoemission study of formation and oxidation of rare earth/magnesium interfaces is presented. Our results indicate that a thin, rare earth rich amorphous surface alloy forms when the rare earths Ce or Pr are evaporated onto a magnesium substrate at room temperature. When these systems subsequently were exposed to…
Abstract In a study of “rana” soils of central Spain, hydroxy-interlayered 2:1 clay minerals were identified in the upper horizons and high-charge smectite in the lower horizons, with kaolinite the most abundant phyllosilicate. The high-charge smectite showed a basal spacing of 18 Å on Mg-saturation and glycerol solva…
There was few post irradiation examination data on the mechanical properties of domestic fuel cladding tubes used for light water reactors, then those data obtained abroad have been often used in the fuel design or fuel performance codes. Although, many reports discussed the deformation mechanism of the tube, almost a…
The effect of controlled heterogeneous nucleation by platinum on the crystallization of a ZrF 4 ‐BaF 2 ‐LaF 3 ‐AlF 3 ‐NaF (ZBLAN) glass was studied. Various levels of platinum were incorporated into this glass by a combination of PtCl 2 ‐doping and melting‐atmosphere variation. The effect of doping levels and melting…
A simplified method for the analysis of hysteresis characteristics in a transformer under nonsinusoidal excitation is discussed. The nonsinusoidal sin m (wt) waveforms are used in the experiments. The hysteresis analysis is treated as a shape identification problem and is solved using the piecewise curve fitting techn…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTModeling the heteroleptic equilibria of organized molecular systems by using a double-titration technique: a novel determination of the fundamental equilibrium constants in a ternary system involving a macrocyclic cobalt(II) complex, dioxygen, and competing axial ligandsNaid…
Abstract Catalysts for environmental protection. The main emitters of anthropogenic air pollution are internal combustion engines, power plants, and production processes. Components of exhaust gases which are regarded as pollutants are hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NO x ), sulfur dioxide (S…
Experimental techniques are described for determining the eutectic composition of multicomponent mixtures of nematic liquid crystals. These techniques were applied to the formulation of nematic esters, when the idealized eutectic composition calculated by the Schroeder-Van Laar relationship did not give a good melting…