Materials Literature
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A study has been made of the exudate provoked by intrapleural carrageenan in rats. Various parameters have been measured including volume of exudate, numbers and types of cells. Pharmacological assay has shown the early release of histamine and 5HT into the exudate followed at later times by a release of prostaglandin…
Relative quantum yields have been measured for O(1S), N(2D), and N2(A 3Σ+u) production from N2O over the wavelength range 1100–1500 Å. The measurements of O(1S) were made by observing the 1S0 → 1D2 emission at 5577 Å. N(2D) was measured via the intensity of NO β bands generated by N(2D)+N2O → N2+NO(B 2Πr) followed by…
Nominally undoped YAl${\mathrm{O}}_{3}$ shows broad intense absorption bands in the visible after irradiation with visible and near uv light at 77 K; they become especially strong after subsequent irradiation with near ir. The bands could be correlated with an ESR spectrum arising from holes, which are trapped at ${\m…
Susceptibility measurements over a wide range of temperatures on concentrated amorphous transition-metal aluminosilicate glasses (11.8-33.5-at.% Co, 12.3-41.7-at.% Mn) are reported. In the high-temperature regime (>\ensuremath{\sim}50 K), these glasses show Curie-Weiss behavior with large negative paramagnetic Curi…
A theoretical model for multilayer antireflection coatings is presented on the basis of the theory of all-dielectric Fabry-Perot interference filters. Effective interfaces are employed, and a new concept of a replacement pair consisting of two layers is introduced. It is shown that incorporation of this pair in a mult…
Abstract A promising technique emphasised in the proposed tannery waste treatment system is surface adsorption. Specific surface adsorption processes studied were foam separation without additives, adsorbing colloid flotation, carbon adsorption, and adsorption flotation. Results show that foam separation without addit…
The theory of voltage gradients in the insulation of high-voltage dc cables insulated with oil-impregnated paper is refined by including the effects of power losses within the insulation. The analysis is performed by means of perturbation theory, which yields formulas that are more convenient to use than the more exac…
The additives and contaminants which occur in textile fibers vary widely, depending on the type of fiber and the pretreatment which it has received. Synthetic fibers such as nylon and polyester contain trace amounts of contaminants such as catalysts and catalyst deactivators which remain after the synthesis of the bas…
Abstract A method has been developed for the solution and subsequent precipitation of chitin that renatures it in highly ordered, crystalline form closely similar to native chitin. Critical factors include the use of a high molecular weight, soluble chitin and an anhydrous precipitation and neutralization system. A mi…
This paper provides background on the basic chemical processes which can occur during the exposure of polymers to typical end-use environments such as air, sunlight, water vapor, and various atmospheric pollutant gases.
Abstract The phase diagram of the quasi‐binary Mn 3 O 4 Al 2 O 3 system in air has been redetermined at temperatures from 850 to 1550°C with the help of the X‐ray powder diffraction technique including high‐temperature diffractometry. Lattice constants of manganese aluminates and the powder diffraction patterns of Mn…
Summary Clay-like, hydrous nickel silicates from Niquelandia, Goias, Brazil, and from Jacupiranga, São Paulo, Brazil, arc examined by X-ray diffraction, chemical analysis, and thermogravimetric methods. The nickel silicates from Niquelandia are ferric iron montmorillonites, with nickel in the octahedral positions and,…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPotassium perchromate as a source of singlet oxygenJohn W. Peters, Paul J. Bekowies, Arthur M. Winer, and James N. Pitts Jr.Cite this: J. Am. Chem. Soc. 1975, 97, 12, 3299–3306Publication Date (Print):June 1, 1975Publication History Published online1 May 2002Published inissu…
Elastic constants are reported for several polycrystalline silicon nitrides with densities between 2.37 and 3.18 g/cm3 in the temperature range 0–1000 °C. The density dependence of the elastic constants is in approximate agreement with the prediction of a theory of composites.
Regions of different proton density in the low density lipoprotein (LDL) particle from human serum have been determined by neutron scattering. From measurements in various H2O/D2O mixtures, the LDL particle appears to be quasi-spherical, with the centers of gravity of the hydrocarbon and polar regions coinciding. The…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTIsotherms and energetics of carbon dioxide adsorption on .gamma.-alumina at 100-300.deg.Michael P. RosynekCite this: J. Phys. Chem. 1975, 79, 13, 1280–1284Publication Date (Print):June 1, 1975Publication History Published online1 May 2002Published inissue 1 June 1975https://…
SUMMARY The taxonomy, distribution, and ecology of the diatom genus Tabellaria Ehr. from a portion of the northcentral United States were studied from collections made from August 1968 to October 1971. Using the transmission electron microscope with carbon replicas of the frustule surfaces, taxonomically significant c…
Abstract DSC investigations on isotactic polypropylene ( it ‐PP) quenched from the melt and annealed over a range of temperatures are reported. The results confirm the existence of saturation levels of the ordered phase for different annealing temperatures, previously revealed by X‐ray diffraction methods. Thermal, X‐…
Bulk photoconductivity produced by the absorption of picosecond optical pulses in silicon transmission-line structures has been used to switch and gate microwave signals. The technique permits the generation of microwave and millimeter-wave pulses as short as a single cycle, and requires only a few microjoules of opti…
Abstract Poly(vinylidene fluoride) exists in three crystalline forms. Optimum conditions for preparing form III were established by infrared spectroscopy, differential scanning calorimetry, and x‐ray diffraction measurements. Form III is easily obtained by annealing mats of solution‐grown crystals of form II at 175–18…