Materials Literature
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A rigorous electromagnetic theory of the diffraction of light by blazed lamellar gratings has been developed. It is applied to calculate the diffracted power distribution of four gratings (R1 − R4) whose grooves have the following depths and widths (b,l) in units of grating period a: (0.433, 0.750), (0.333, 0.667), (0…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTApplication of secondary .alpha.-deuterium kinetic isotope effects to studies of enzyme catalysis. Glycoside hydrolysis by lysozyme and .beta.-glucosidaseF. W. Dahlquist, Tsafrira Rand-Meir, and Michael A. RafteryCite this: Biochemistry 1969, 8, 10, 4214–4221Publication Date…
Abstract Poly( p ‐phenylene sulfide), a poly(arylene sulfone), and a poly(arylene sulfonate) were subjected to thermal degradation in vacuo , at temperatures between 250 and 620°C. The volatile and solid degradation products were analyzed by mass spectroscopy, infrared spectroscopy, and elemental analysis. The major d…
Phase relationships in the system are first presented on P-T projections of three different composition joins. Crystalline phases encountered include albite, analcite, coesite, jadeite, nepheline, and quartz. Vapor-saturated melting curves proceed with negative dP/dT slopes to invariant points of pressures between 10…
Simultaneous hydrolytic decomposition of barium bis isopropoxide and titanium tetrakis tertiary amyloxide was used to produce stoichiometric BaTiO 3 . The particle size range was 50 to 150 Å. The purity was 99.98+%, the major contaminant being silicon from the glass apparatus. The homogeneity and stoichiometry of the…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDerivatization of cross-linked polyacrylamide beads. Controlled introduction of functional groups for the preparation of special-purpose, biochemical adsorbentsJohn K. Inman and Howard M. DintzisCite this: Biochemistry 1969, 8, 10, 4074–4082Publication Date (Print):October 1…
The pyroelectric coefficient (at constant stress) of a 95 wt% BaTiO3, 5 wt% CaTiO3 ceramic composition (Clevite Ceramic B) was measured over the temperature range from 4.9° to 400°K. Extrema in the pyroelectric coefficient were observed at the rhombohedral-orthorhombic transition point (150°–170°K), the orthorhombic-t…
Increasing industrial uses of platinum and its associated metals – palladium, rhodium, ruthenium, iridium and osmium – have occasionally given rise to doubts as to the future availability of adequate supplies. This has sometimes discouraged research workers from considering the advantages of these metals in their sear…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthetic spectroscopic models related to coenzymes and base pairs. III. A 1,1'-trimethylene-linked thymine photodimer of cis-syn structureNelson J. Leonard, Krzysztof Golankiewicz, Robert S. McCredie, Suzanne M. Johnson, and Iain C. PaulCite this: J. Am. Chem. Soc. 1969, 91…
Diatoms are usually the major component of the algal flora in many streams, although green and blue-green algae may be present. These experiments were designed to determine if high temperature or a shift in the chemical composition of the water might bring about a dominance of blue-green algae and/or green algae rathe…
Absorption and fluorescence spectra of Co2+ in the tetrahedral (Td) site of ZnAl2O4 spinel (gahnite) at low temperatures have been observed and analyzed. The resulting energy-level diagram includes four quartet states and nine doublets, and has been interpreted first in terms of a weak field formalism without spin–orb…
Abstract The infrared absorption of poly(ethylene glycol) was measured in the molten state. Characteristic bands of the molten state were identified. Normal vibrations and frequency distributions were treated for various conformation models with CH 2 CH 2 O repeat units. The infrared absorption peaks of the molten sta…
A study has been made of the stress-strain behaviour, secondary slip geometry and slip line morphology of niobium single crystals purified by annealing in ultra-high vacuum. Within favourable limits of orientation, temperature and strain rate the stress—strain curves exhibit well-defined three-stage hardening. The pri…
Studies of the x-ray diffraction pattern from different potassium graphites have shown that intercalation of graphite by potassium is accompanied by an expansion of the carbon layers. This expansion is uniform within a single layer and is constant for all n carbon layers separating successive intercalate layers in the…
SUMMARY In order to obtain data comparable to those of B iscaye (1965) on the Atlantic Ocean, the authors carried out quantitative X‐ray determinations of clay minerals in the sediments of the Indian and Pacific oceans using the Biscayemethod.
Abstract Polyethylene, polypropylene, poly(vinyl fluoride) (Tedlar), polystyrene, nylon 6, poly(ethylene terephthalate) (Mylar), polycarbonate, cellulose acetate butyrate, and a poly(oxymethylene) copolymer were treated with activated helium and with activated oxygen. Mechanical strengths of adhesive‐bonded specimens…
An apparatus has been designed and constructed that will allow determination of the mechanical behavior of polymer specimens subject to applied tensile and compressive loading, while the sample is simultaneously subject to a hydrostatic pressure environment. The moduli of high-density polyethylene and polypropylene de…
The six lowest excited states of benzene have been investigated in the gas-phase free molecule at low pressure by electron-impact spectroscopy. Incident electron energies of 13.6 and 20.0 eV and scattering angles from 9° to 80° were used. Three singlet–singlet transitions at 5.0, 6.2, and 6.9 eV were identified. These…
Abstract Most thermoplastics far below their glass transition give a brittle fracture when de‐formed in uniaxial tension. Bisphenol‐A polycarbonates are an exception and deform in a ductile manner. However, it has been observed in Izod impact studies of notched samples that the mode of failure changes from a ductile t…
Abstract The glass transition temperature, dynamic shear moduli, and bulk viscosities of Phenoxy PKHH (a thermoplastic polymer made from bisphenol‐A and epichlorohydrin) filled with glass beads and Attapulgite clay were investigated. The glass temperature of the polymer increased with increasing filler concentration a…