Materials Literature
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Volume crystallization of this glass is nucleated by Li 3 PO 4 . On heating from room temperature, Li 2 SiO 3 appears around 650°C and then converts to Li 2 Si 2 O 5 around 850°C by reaction with SiO 2 from the melt. Preheating the glass at 1000°C forms larger Li 3 PO 4 nuclei that promote additional crystallization o…
A commercial lithium aluminosilicate glass‐ceramic material is investigated by high‐resolution transmission electron microscopy after different heat treatments. Evidence is presented that epitaxy of β‐quartz crystals on ZrTiO 4 ‐type crystallites is the critical step initiating silicate crystallization.
Recently the problem of the glass transition has been further complicated by the discovery of a phase which forms under conditions similar to those required by the formation of metallic glasses. This new phase (the “quasicrystal”) seems to be structurally intermediate between the glass and the crystal phase, being cha…
A formal expansion in spherical harmonics or Cartesian tensors of the pair correlation function of a liquid subjected to a shear rate is discussed. Expressions for the coefficients to tensor rank 4 are evaluated via a nonequilibrium molecular-dynamics simulation of an inverse twelve soft-sphere liquid undergoing Couet…
The insulation from six 5 kV power cables, which has been in service underground for 6 to 8 years, was examined by infrared (IR) spectroscopy and oxidation induction time (OIT) analysis. Sections of insulation containing water trees were found to contain high levels of ionic contaminants. All insulation samples showed…
Abstract We found 10 miscible pairs of dissimilar polymers that rendered birefringence‐free polymer blends. Each pair consists of a positive birefringence polymer and a negative one. Zero birefringence in the blend is attained as the result of compensation of positive and negative contributions to the overall birefrin…
(Ca,Mg) carbonates have been studied by solution calorimetry at 85C in an acid solvent (lM IJ)I) that was saturated at room temperature with NaCl and contained 0.7 5M CaCl, and 0.25M MgClr. The enthalpy of formation of ordered dolomite from calcite and mag' nesite at 85C is -5.74 + 0.25 kJ/mol, for a formula unit of d…
Abstract Copolymerizations of glycolide with L , L ‐dilactide were conducted in chloroform, 1,2‐dichloroethane and nitrobenzene. Chlorosulfonic acid, triflic acid, boron trifluoride, triethyloxonium tetrafluoroborate, but mainly methyl triflate, were used as initiators. 50°C was found to be an optimum reaction tempera…
Single crystals of copper-based manganese alloys (Cu−1.05, 1.3, 3.3, 5.05 and 11.6 at.%Mn) were grown and deformed in tension at room temperature. The weakbeam method of electron microscopy has been used to resolve the partial dislocations and to determine the stacking-fault energy γ. Contrary to most other Cu alloys,…
Abstract The crystallization behavior of three molecular weight samples of poly(ε‐caprolactone) has been studied as a function of temperature. Crystallization begins in the form of axialities and changes to spherulite growth as time progresses, presumably owing to the molecular weight distribution. Determinations of e…
An electrochemical series of redox couples, originally developed for Savannah River Laboratory glass frit 131 (SRL‐131) as a reference composition, has been extended to two other alkali borosilicate compositions that are candidate glasses for nuclear waste immobilization. Because no dramatic differences were ascertain…
Slow strain rate tests (SSRTs) on differently shaped tensile specimens machined from two heats of Alloy 600 tubing were conducted at 350 C in deaerated aqueous solutions containing small amounts of lithium hydroxide and boric acid at different partial pressures of hydrogen, using a recirculating autoclave system. In a…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTBlends of polycarbonate and poly(methyl methacrylate) and the determination of the polymer-polymer interaction parameter of the two polymersWoo Nyon Kim and Charles M. BurnsCite this: Macromolecules 1987, 20, 8, 1876–1882Publication Date (Print):August 1, 1987Publication His…
High-resolution x-ray measurements have been performed at the synchrotron of LURE (Orsay) to study both uniaxial (discotic and calamitic) and biaxial nematic lyomesophases of the mixture K-laurate, 1-decanol, and D2O. The variations of the densitometric profiles of the diffracted bands are analyzed vs temperature. The…
The formation of oxide layers from porous silicon layers formed on P substrates which present different and well-controlled porous textures is studied in detail. It is shown that the overall process leading to oxides with properties similar to standard thermal oxides consists of two steps: the oxidation of silicon in…
The relation between grain size and grain‐boundary microcracking during cooling in aluminum titanate ceramics was studied. Microcracking temperature was determined by the measurement of thermal contraction and expansion, which was accompanied by acoustic emission. When the ceramics were cooled at a rate of 6°C/min, st…
The effects of experimental parameters on surface-enhanced Raman scattering (SERS) for silver-coated microsphere substrates were investigated. The parameters included sphere size, silver thickness, and excitation wavelength. The SERS signal intensity varied as each of these parameters was changed. The potential for in…
Using a generalized Landau type of free-energy density, we develop a theoretical model which, in a unified way, describes the general features of the tilt, polarization, pitch, dielectric susceptibility, and heat capacity of ferroelectric liquid crystals. Rewriting the equations into dimensionless form, we show that s…
The processing of interstellar dust grains by strong shock waves is studied, with the emphasis on the effects of grain-grain collisions. Such collisions provide the high pressures required to transform interstellar graphite and amorphous carbon grains into diamonds. Diamond metamorphism is as important for the destruc…
A phenomenological model of a vibrating 90°-domain wall in an electric and mechanic stress field is presented. The model allows to separate the domain wall and the volume contribution to the complex dielectric, piezoelectric and elastic constants. The results are compared with representative measurements of the above…