Materials Literature
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Abstract IR transmission spectra are measured at (Bi 1− x Sb x ) 2 Te 3 single crystals with x = 0.5, 0.7, 0.9 near the absorption edge at 84 and 300 K. For the determination of the optical constants also the reflectivity of polarized infrared light is recorded in the plasma range at 300 K. The dependence of the free…
Complex values of the permittivity tensor of robber sheets which are manufactured by the rolling process were estimated by the least-squares method using the reflection coefficient measured for normal incidence. First, the frequency characteristics of the reflection coefficients of a rubber sheet backed by thin alumin…
Highly thermally conductive aluminum nitride ceramics were metalized by an electroless plated Ni‐P film for the purpose of utilizing them in practical electronic circuit substrates. Aluminum nitride substrates were effectively etched by solution, and the adhesion strength between and the Ni‐P film was found to increas…
Abstract Selective sulfation of the primary hydroxyl group of chitosan was performed by means of the pyridine‐SO 3 complex after the positions 2 and 3 of the aminoglucopyranosidic ring were protected by coordination with copper ions. The requirements for complexing copper ions were investigated as a function of the pH…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and characterization of a platinum-mercury "A-frame" clusterPaul R. SharpCite this: Inorg. Chem. 1986, 25, 23, 4185–4189Publication Date (Print):November 1, 1986Publication History Published online1 May 2002Published inissue 1 November 1986https://doi.org/10.1021/i…
This study was an attempt to develop implantable sustained release forms of drugs, based on formulations containing chitosan, a biodegradable polymer from a natural source, and hydroxypropylchitosan (HP-chitosan), its water-soluble derivative. The possibilities were explored using uracil as a model for anticancer drug…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThermal decomposition processes in aliphatic-aromatic polyamides investigated by mass spectrometryAlberto Ballistreri, Domenico Garozzo, Mario Giuffrida, Pietro Maravigna, and Giorgio MontaudoCite this: Macromolecules 1986, 19, 11, 2693–2699Publication Date (Print):November…
5-Pyridoxic-acid oxygenase, a cytoplasmic enzyme formed when Arthrobacter Cr-7 is grown with pyridoxine as a sole source of carbon and nitrogen, was purified about 190-fold to homogeneity from fully induced cells. The enzyme catalyzes Reaction a, (Formula: see text) the essential ring-opening step in the degradation o…
The photoabsorption and fluorescence cross sections of HBr were measured in the 105–235 nm region using synchrotron radiation as a light source. Sharp absorption bands were observed in the 105–120 nm region. These bands were classified into Rydberg series, and their oscillator strengths were measured. Fluorescence in…
Pure, crystalline, fine particulate calcium zincate was prepared. Its chemical composition, was established by chemical analysis, weight loss in thermogravimetric analysis, and by x‐ray powder diffraction pattern. Its solubility in different solutions at 298 K was determined. The solubility data were used to determine…
Liquid crystals were discovered about ninety years ago. The Austrian botonist Reinitzer [1] observed that cholesteryl benzoate has two sharp melting points at ∼145 and 179°C. At 145°C the solid crystalline material changed to a hazy anisotropic liquid which at 179°C became a clear, transparent, and isotropic phase. Th…
X-ray photoelectron spectroscopy with variable takeoff angles has been used to study the nitridation of Si(100). The air-oxidized layer on the silicon film has been cleaned off by an Ar radio frequency (rf) plasma, and nitridation was obtained at temperatures around 400 °C in a rf plasma of a NH3 (5%)-N2(95%) mixture.…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructure and magnetism in ACuCl3 salts containing bibridged chains with square-pyramidal coordination geometryU. Geiser, R. M. Gaura, R. D. Willett, and D. X. WestCite this: Inorg. Chem. 1986, 25, 23, 4203–4212Publication Date (Print):November 1, 1986Publication History Pub…
Abstract The role of organic ligands of different ability to complex with Al 3+ in affecting the formation of allophane and imogolite and the nature of the precipitation (>0.01 µm) and soluble (<0.01 µm) products was investigated at initial Si concentration of 1.6 × 10 −3 mol.L −1 , Si/Al molar ratios of 0.5 and…
Abstract The molecular order and mobility of two liquid‐crystalline polyacrylates with phenyl benzoate moieties as mesogenic side groups and (CH 2 ) m spacers ( m = 2 and m = 6) were investigated by pulsed 2 H NMR. The mesogenic side groups were isotopically labelled at the terminal phenylene ring. In the glassy state…
The dc conductivity of a sintered sample of Y 2 O 3 containing an excess of lower‐valent metal (Ml) impurities has been measured at 600° to 1100°C in air as a function of the water vapor pressure (0.4 to 3000 Pa). The logarithm of the p ‐type conductivity vs log P H2o has a slope of – 1/2 in certain regions of F H2o a…
When a nematic liquid-crystal cell is driven by a dc electric field, the capacitance of the cell increases in the first several tens of milliseconds, but after that the capacitance tends to decrease with a rather long relaxation time of the order of 1 s. This phenomenon can be explained by impurity ions which form the…
Densification of two‐dimensional arrays of nearly monosized copper spheres was examined by hot‐stage optical microscopy. The evolution of the particle arrangement was studied with computer methods, and statistical correlations were sought. Color graphics were found useful for displaying the spatial relationship of the…
Abstract Several classes of organosilicon polymers are effective precursors for silicon carbide ceramic compositions. These include polydimethylsilane (via a two‐step process), ‘polysilastyrene’, polycarbosilazanes or polysilazanes, and certain siloxanes, plus the branched polycarbosilanes, branched polysilahydrocarbo…
We report, for the first time to our knowledge, on high-resolution x-ray scattering measurements of the liquid crystal 4'-butoxyphenylester 4-decyloxybenzoic acid (4OP10OB) with emphasis on the smectic-C phase and the smectic-A to smectic-C phase transition. From angular scans in reciprocal space we found that the sme…