Materials Literature
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The Poincaré sphere representation, a geometrical method for solving problems involving the propagation of polarized light through birefringent and optically active media, is applied to several electrooptic liquid crystal problems. The emphasis is on the twisted nematic case, for which the quiescent state solution was…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDetection and characterization of the long-postulated iron-dioxygen-iron intermediate in the autoxidation of ferrous porphyrinsDer-Hang Chin, John Del Gaudio, Gerd N. La Mar, and Alan L. BalchCite this: J. Am. Chem. Soc. 1977, 99, 16, 5486–5488Publication Date (Print):August…
In a preliminary study of the enzyme-polymer interactions, the role of 15 enzymes in the in vitro hydrolysis of polyglycolic acid has been investigated. Carboxypeptidase A, alpha-chymotrypsin, clostridiopeptidase A and ficin increase the rate of hydrolysis of this synthetic polymer, illustrating the ability of enzymes…
Ionic and electronic conductivity has been measured in and . Ionic conductivity was measured by using as a blocking electrode for electronic conduction. Transference numbers were confirmed by cells of the type . Ionic conductivities were for and , respectively, at room temperature. The conductivity of increases abrupt…
The authors performed optical measurements consisting of near normal incidence reflectance (2-11 eV) and multiangle reflectance measurements (11-15 eV) on gallium films condensed on cooled glass substrates in a vacuum of 2*10 -10 Torr. Optical constants were determined with the help of a Kramers-Kronig analysis of the…
The ESR spectra of single crystals and amorphous thin films of W${\mathrm{O}}_{3}$ have been measured in the temperature range 77-300\ifmmode^\circ\else\textdegree\fi{}K. In the case of single crystal the observed resonance lines were identified as due to ${\mathrm{Mo}}^{5+}$ ions. The observed values are: ${g}_{\math…
Normal incidence measurements of single-layer gradient refractive-index antireflection films, produced by a chemical etch-leach process on glass sensitized by a phase-separating heat treatment, indicate very low reflection over a broad wavelength regime, 0.35–2.5 μm. First-surface measurements of the reflectance of th…
Many of the physical properties of crystalline solids depend on the presence of native or foreign point def ects. In pure compound crystals the native defects are atoms missing from lattice sites where, according to the crystal structure, atoms should be (vacancies); atoms present at sites where atoms should not be (i…
The spin waves in a Heusler alloy Cu 2 MnAl were investigated at several temperatures by neutron inelastic scattering. The spin wave dispersion relations along three principal directions were systematically explored across the whole magnetic Brillouin zone at 4 K. The results were analysed using the Heisenberg Hamilto…
Abstract Photochromism of N-salicylideneanilines and related compounds was studied by measuring the electronic and vibrational spectra of the transient species. The rise time of the transient electronic spectra of the photochromic colored species was measured by picosecond time-resolved spectroscopy and was found to b…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOrganic alloys: synthesis and properties of solid solutions of tetraselenafulvalene-tetracyano-p-quinodimethane (TSeF-TCNQ) and tetrathiafulvalene-tetracyano-p-quinodimethane (TTF-TCNQ)E. M. Engler, B. A. Scott, S. Etemad, T. Penney, and V. V. PatelCite this: J. Am. Chem. So…
Urease was purified 24-fold from extracts of Klebsiella aerogenes. The enzyme has a molecular weight of 230,000 as determined by gel filtration, is highly substrate specific, and has a Km for urea of 0.7 mM. A mutant strain lacking urease was isolated; it failed to grow with urea as the sole source of nitrogen but did…
The partitioning of NaAlSi/sub 3/O/sub 8/ between coexisting microcline and plagioclase solid-solutions is modeled using published Margules parameters for microcline-low albite solid-solutions. Variations in the structural state of the alkali feldspar may shift the temperature calculated from coexisting feldspar pairs…
lnfrared spectra ofthe coordinated water in palygorskite were studied at different degrees of exchange of deuterons and protons. The single peaks observed for the bending fundamental of isotopically diluted HrO and DzO show that all the coordinated water molecules are equivalent, as suggested by Bradley's structure de…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSystematic synthesis design. 6. Yield analysis and convergencyJames B. HendricksonCite this: J. Am. Chem. Soc. 1977, 99, 16, 5439–5450Publication Date (Print):August 1, 1977Publication History Published online1 May 2002Published inissue 1 August 1977https://doi.org/10.1021/j…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectronic structure of low-spin cobalt(II) Schiff base complexesM. A. HitchmanCite this: Inorg. Chem. 1977, 16, 8, 1985–1993Publication Date (Print):August 1, 1977Publication History Published online1 May 2002Published inissue 1 August 1977https://pubs.acs.org/doi/10.1021/i…
A new experimental approach is presented for studying the charge-transfer process involved in the chemisorption on polar semiconductors. This approach utilizes the surface piezoelectric effect, contact potential difference measurements, and surface photovoltage spectroscopy. From the study of oxygen adsorption on ZnO…
The single-crystal material has a resistivity at 300 degrees C of 4.7 Omega cm and an activation energy of 0.13 eV. In the polycrystalline case it has been possible to separate out the bulk and grain boundary contributions to the total electrolyte resistance. These have activation energies of 0.15 and 0.26 eV respecti…
Hot corrosion is a form of accelerated oxidation of alloys which can occur in combustion gases in the presence of impurities. The characteristics of the reaction are defined by describing practical examples, and then the results of a variety of laboratory experiments are considered in relation to the practical process…
A technique is presented for the simultaneous determination of thermal conductivity and thermal diffusivity of biomaterials. Measurements are derived from the transient power supplied to a thermistor probe operated in a self-heated mode. The thermal properties are extracted through the use of an appropriate thermal mo…