Materials Literature
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Electrical conductivity and the ionic and electronic transference numbers were determined for two types of unintentionally doped single crystalline sapphire for current directions perpendicular to the r plane (1102). One was acceptor dominated and the other was initially donor (H i x ) dominated, changing to acceptor…
The microstructure of the built-up edges of a number of alloys has been examined using both optical and electron microscopy. The built-up edges of the two ferrific steels examined showed that these were significantly different to those formed in austenitic stainless steel and Cu–40Zn brass. The built-up edge deformati…
Typical Bs type phase solubility diagrams were obtained for α-and β-cyclodextrins (α-CyD and β-CyD) with methyl cinnamate, ethyl cinnamate, and cinnamaldehyde in water at 25°. Solid complexes for α-and β-CyDs with three guest molecules were obtained and their molar ratios were found to be 2 : 1 (α-CyD/guest molecule)…
The existence of compounds between Si 3 N 4 ‐CeO 2 and Si 3 N 4 ‐Ce 2 O 3 was investigated for firing temperatures of 1600° to 1700°C. The two new monoclinic compounds found were Ce 2 O 3 ·2Si 3 N 4 with lattice parameters a = 16.288, b = 4.848, and c =7.853 Å and β=91.54° and Ce 4 Si 2 O 7 N 2 with lattice parameters…
Abstract A static platelet adhesion test using whole human blood was employed to assess the affinity of various bare polymer (sulfonated polystyrene, acetal resin, Teflon FEP, polystyrene) surfaces as well as various surfaces of glass and polymers that were coated with plasma proteins. Platelet adhesion to the bare po…
In this paper, an evaluation of the methods of finite elements and finite differences, as applied to nonlinear magnetic field problems in electrical machines, is presented. The evaluation covers the aspects of effectiveness, numerical accuracy, modeling implementation considerations as well as computer storage and exe…
The phase relations in the system HfO 2 ‐Sm 2 O 3 were studied by high‐temperature and room‐temperature X‐ray diffraction. The areas of existence of the solid solutions based on HfO 2 , Sm 2 Hf 2 O 7 , and Sm 2 O 3 were determined using the lattice parameter method. Also, the influence of small additions of Sm 2 O 3 o…
Emission and excitation spectra for Ce 3+ in CaS have been observed at 75 K. They exhibit sharp phonon replicas due to pseudolocalized lattice vibrations. The observed frequencies of the pseudolocalized vibrations are 293 and 209 cm -1 in the emission spectra, and 282 and 206 cm -1 in the excitation spectra. Peak posi…
Abstract Graft polymerizations of vinyl acetate onto granular corn starch were initiated by cobalt‐60 irradiation of starch‐monomer‐water mixtures, and ungrafted poly(vinylacetate) was separated from the graft copolymer by benzene extraction. Conversions of monomer to polymer were quantitative at a radiation dose of 1…
Abstract Die ternären Selenide Rb 3 Cu 8 Se 6 und Cs 3 Cu 8 Se 6 konnten durch Umsetzungen von Alkalimetallcarbonaten mit Kupfer und Selen in der Schmelze synthetisiert werden. Röntgenbeugungsuntersuchungen an Einkristallen führten zur Struktur der isotypen Verbindungen. Die monoklinen Elementarzellen enthalten zwei F…
Polygonal defect arrays in lipid liquid crystals prepared from dipalmitoyl-, dimyristoyl-, and dilaurylphosphatidylcholine with various concentrations of water have been observed and characterized using optical microscopy. These arrays appear similar to the polygonal arrays previously observed in thermotropic smectic…
Abstract The most important techniques of those currently used in Home Office forensic science laboratories for the analysis of fiber dyestuffs are thin-layer chromatography and visible absorption spectroscopy of dye solutions. To obtain useful discrimination 20 to 50 ng of each dye component must be extracted. In mos…
Mono and diesters of itaconic acid have been pi'epared using linear , branched or cyclic alkane structures . These have been homo and copolymerized to produce a wide range of polymers with differing properties. These range from polyacids to polydiesters to ionomeric structures. Their physical behaviour has been examin…
A review of six years operational experience in using the slow strain test procedure has indicated several unique advantages associated with dynamic strain techniques and also identified an area of limitation. The chief advantage of the dynamic slow strain test procedure is that it is much more aggressive in producing…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructural Selectivities in the Reduction of Poly(vinyl chloride) with Lithium Aluminum Hydride and Tri-n- butyltin HydrideW. H. Starnes Jr., F. C. Schilling, K. B. Abbås, I. M. Plitz, R. L. Hartless, and F. A. BoveyCite this: Macromolecules 1979, 12, 1, 13–19Publication Dat…
A V.G. Microscopes' HB5 STEM has been used to study a segregated copper-bismuth alloy. It is shown that the Z contrast mechanism due to Crewe (1970 a, b) is not valid for such crystalline materials. Attempts to use the energy loss spectrometer, with which the microscope is fitted, to detect the bismuth spectrum from t…
We study in detail the defect structure observed in a cylindrical geometry near the smectic A-cholesteric transition. The orientation of the molecules at the capillary surface is radial. We propose that the cholesteric phase grows from the smectic A phase via a spiralling S = + 2 disclination. Unlike a nematic which r…
Both forward angle and 90 degrees light-scattering measurements have been used for cell sizing with stream-in-air flow systems with very little theoretical base for the measurements. Mie theory calculations are compared with measurements on plastic microspheres. Detector response for homogeneous spheres is shown to be…
Thermotropic liquid crystals offer uniquely ordered media for intermolecular reactions such as polymerization. Unlike the recently investigated topochemical polymerizations where molecules are rigidly constrained on lattice points [l], the liquid crystalline state permits full two-dimensional (nematic and cholesteric)…
The anchoring energy of a nematic liquid crystal can be evaluated from measurements of the tilt angle at the boundary of its substrate. The equilibrium between surface and elastic energies determines the geometric structure of the distortion. For an obliquely evaporated SiO film, the energy value is about 10-3 erg/cm2.