Materials Literature
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Abstract The 14 N nuclear quadrupole relaxation time and resonance frequencies v + , v - , and v d of N,N-dimethylnitramine were measured between 14 and 313 K. The frequency increase of v + and v - observed below T c (108 K) is explained by the increase of p π electrons in the amino nitrogen caused by the deformation…
Abstract Einkristalle von Ba 25 Cu 14 2+ Cu 4 3+ Zn 4 O 49 wurden mit einer Kombination von Feststoff‐ und Schmelzmittel‐reaktionen dargestellt. Diese Substanz kristallisiert tetragonal, Raumgruppe D 7 4th –P4/nmm mit a = 18,2146, c = 9,3230 Å, Z = 2. Der bisher unbekannte Strukturtyp zeigt Kupfer in tetragonal pyrami…
Field measurements of beta ray energy spectra have been carried out at various locations in CANDU nuclear generating stations operated by Ontario Hydro. The beta ray energy spectrometer consists of a 5 cm diameter x 2 cm thick BC-404 plastic scintillator situated behind a 100 µm thick, totally depleted, silicon detect…
By means of high pressure differential thermal analysis we measured the pressure/temperature phase diagrams of several nematic compounds with different molecular structures. Using pressures up to about 500 M Pa we found strongly nonlinear clearing curves. This behaviour is interpreted as changes from ‘weak’ intermolec…
Free and moving boundary problems require the simultaneous solution of unknown field variables and the boundaries of the domains on which these variables are defined. There are many technologically important processes that lead to moving boundary problems associated with fluid surfaces and solid-fluid boundaries. Thes…
Abstract Reactive polymer blending of poly(β‐hydroxybutyrate) (PHB) and its valerate copolymers (PHBV) are reported, following two different methodologies, namely polymerization of rubber inclusions in the preformed matrix or reactive melt blending of preformed polymers. As second phase, poly(butyl acrylate) (PBA) and…
Crystallization behavior of cordierite-based glass with excess SiO 2 and Al 2 O 3 (CM glass) was studied at the initial crystallization stage. Two kinds of glass-in-glass phase separation occurred during the heat treatment of glass powder. The secondary glass-in-glass phase separation, which consists of an SiO 2 -rich…
Using Green's functions, we reformulate Kirchhoff's laws for a two-component random resistor network in which a fraction p of the resistors has conductance ${\mathrm{\ensuremath{\sigma}}}_{\mathrm{\ensuremath{-}}}$ and the remainder have conductance ${\mathrm{\ensuremath{\sigma}}}_{+}$. In this Green's-function formul…
Wave phenomena in intensely loaded bodies are often paradoxical and unexpected. They are evoked by stress wave interactions and depend substantially on actual material properties, body shapes and dimensions, friction, etc. Their proper understanding is indispensable for the reliable evaluation of the quality of variou…
Potassium permanganate/sodium bisulphite redox system induced polymerization of methacrylic acid (MAA) with viscose fabric was studied under a variety of conditions. The polymerization reaction was studied with respect to graft yield, homopolymer, total conversion and graft efficiency. Results obtained indicated that…
It was found for the first time that the electrical conductivity of Y-substituted Cd 2 Sb 2 O 7 , Cd 2(1- x ) Y 2 x Sb 2 O 7 , with the pyrochlore structure, is larger than at least 3.3×10 0 Scm -1 and the optical band gap of the sample is wider than 3.5 eV. These values indicate that Cd 2(1- x ) Y 2 x Sb 2 O 7 pyroch…
Chemithermomechanical pulps (CTMP) were produced from Eastern black spruce chips in a two-stage pilot plant using different conditions of chemical pretreatment and refining intensity. The conventional CTMP was produced by impregnating chips with sulfite liquor at a pH of approximately 10 and the conducting the first-s…
The fact that business is good in aluminum welding is a sure sign that more manufacturers and fabricators are using GMA and GTA welding to build new products out of this lightweight nonferrous metal. Among the most widely specified weldable grades are Alloys 6061, 5083, 5052 and 5454. A rundown on these four alloys, i…
Abstract The pyrolysis of polyvinyl chloride (PVC) has been described in terms of a relatively simple kinetic model, based on a large number of laboratory tests. The model predictions are in a good agreement with experimental data, regarding hydrochloric acid and non‐condensable combustible gases. Therefore, the propo…
Consolidation of highly degraded silk artifacts is difficult because there is no entirely satisfactory treatment. One option recently introduced to the field of conservation is parylene-C, a polymer whose unique gas-phase deposition method allows extremely thin (below lμm), highly conformal coatings to be applied. The…
Abstract The reconstructive high-temperature transformation of NaAlSiO 4 nepheline to carnegieite, stuffed derivatives of the SiO 2 phases tridymite and cristobalite, has been studied by light microscopy and X-ray precession photographs. X-ray precession patterns of single crystals heattreated between 1543 K and 1593…
The initiation and propagation of hydrogen cracks in a pure iron single crystal have been investigated via notched tensile tests with simultaneous cathodic charging of hydrogen. The notch opening displacement for hydrogen crack growth when the tensile direction was parallel to [001] was much smaller than for [110] ten…
In situ observations by the synchrotron white beam X-ray topographic method are carried out during the directional solidification of thin samples (0.2-0.3 mm) of a Al-0.73 wt% Cu alloy. Stresses associated to morphological instability and pattern formation are analysed. Due to compressions and dilatations induced by t…
Abstract A method is developed for the calculation of the saturation temperature of a KCI‐NaCI aqueous solution, based on the measurement of the density and temperature of a sample solution, and prior knowledge of the NaCl concentration. Experimental density and solubility data for solutions saturated with KCI in the…
A new method to measure the elastic anisotropy of liquid crystals is presented. The method is based on the determination of the transverse spatial decay of the molecular director profile across the shadow region of a truncated laser beam intense enough to reorient the sample. The effective optical Kerr constant due to…