Materials Literature
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Determination of the structure of biological particles, randomly oriented in solution, from spatial correlation analysis of fluctuations in x-ray scattering has recently been proposed. The feasibility of scattering fluctuation measurements was evaluated by using an x-ray synchrotron radiation camera to obtain the spat…
Isotropic tensors play an important role in the theory of many physical processes, which take place in gases and liquids. In such systems it is usually necessary to perform a rotational average on products of direction cosines relating the space-fixed and molecular coordinate frames. The average is generally expressib…
Kinematic and dynamic conditions for the existence, or otherwise, of viscous eddies due to point, ring or a line distribution of stokeslets near no-slip boundaries are investigated. Boundaries considered are (i) a single plane boundary, (ii) two parallel plane boundaries, (iii) an infinite cylinder, and (iv) a finite…
Abstract The microstructure of polyvinyl chloride (PVC) controls much of its processing and property behavior. A model put together from X‐ray diffraction and small‐angle scattering data, swelling data, and processing data shows that PVC crystallites, of a wide melting range and spaced at 0.01 micron, act as crosslink…
Abstract The reinterpretation of the EPR investigations of electron irradiated and doped zinc oxide reveal that the EPR signal with the g ‐factor near 1.96 has to be attributed to the conduction electron. Oxygen vacancies with the EPR signal near 1.99 solely can be created by electron irradiation or strong mechanical…
Abstract The processes taking place during decomposition of montmorillonite by percussive grinding have been studied by IR, X-ray and DTA methods. Destruction can be described as a series of parallel changes in the montmorillonite structure which proceed at various rates. The fastest is a change in status of the excha…
Abstract Well-dispersed fine and stable colloidal platinum is easily prepared by refluxing the solution of chloroplatinic acid in alcohol (and water) in the presence of poly(vinyl alcohol) or polyvinylpyrrolidone under air. The catalytic activity of the colloidal platinum for light-induced hydrogen evolution from wate…
Abstract In many emulsion systems, creaming occurs during the first stage of emulsion breakdown. To reduce the rate of creaming, emulsions having small and uniform droplets are desirable. In this work, types and HLB of nonionic surfactants, emulsification methods, and combinations of oils and nonionic surfactants were…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFacile reduction of carbon dioxide by anionic Group 6b metal hydrides. Chemistry relevant to catalysis of the water-gas shift reactionDonald J. Darensbourg, Andrzej Rokicki, and Marcetta Y. DarensbourgCite this: J. Am. Chem. Soc. 1981, 103, 11, 3223–3224Publication Date (Pri…
Thin SiO2 layers prepared by oxidizing an organo-silane in an Ar/O2 rf plasma discharge produce parallel alignment for nematic liquid crystals with essentially zero tilt. In addition, if the rf plasma system is arranged to produce an Ar/O2 beam, uniform parallel alignment can now be obtained with the director in the s…
X-ray diffraction was used to monitor the effects of electron microscope fixation, staining, and embedding procedures on the preservation of the three-dimensional crystalline order in collagen fibrils of rat tail tendon. A procedure is described in which the characteristic 3.8-nm lateral spacing is preserved, with inc…
Abstract We report structural changes in commercial multifilament poly(ethylene terephthalate) (PET) yarn when it is heat set in silicone oil over a range of temperatures between 100 and 220°C for times ranging from 1 min to 1 hr, while the yarn was (1) free to relax, and (2) held taut at constant length. In one case,…
An assay for the adhesion of Amphora coffeaeformis (Bacillariophyceae) to glass is described. Ca and Sr promoted adhesion, but Ba and Mn were ineffective. Adhesion was inhibited by cycloheximide, carbonyl cyanide 3-chlorophenyl hydrazone, and alpha-isopropyl-alpha-[(N-methyl-N-homoveratryl)-gamma-amino- propyl]-3,4,5-…
We have derived an approximate expression for the threshold pressure for transient acoustic cavitation and have used this result with published expressions for the thresholds for gas bubble nucleation and for rectified diffusion in synthesizing cavitation prediction charts for water covering a frequency range from 10…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMetalloporphyrins with unusual geometries. 1. Mono-, di-, triatom-bridged porphyrin dimersKazuyuki Tatsumi and Roald HoffmannCite this: J. Am. Chem. Soc. 1981, 103, 12, 3328–3341Publication Date (Print):June 1, 1981Publication History Published online1 May 2002Published inis…
Abstract Collagen exists in at least five genetically distinct forms and the relative abundance of these is determined by the type and age of the tissue. Methods are presented for the detection and estimation of these collagens based on appropriate chemical, physical, histochemical and immunological techniques. The sp…
Abstract An experimental and theoretical study was carried out to achieve a better understanding of bubble growth during the filling of gas‐charged molten polymers into a rectangular mold cavity. For the experimental study, a rectangular mold cavity (15.24 × 4.55 × 0.64 cm) was constructed, with glass windows on both…
The oxidation kinetics of sintered α‐ and hot‐pressed SiC were investigated over the temperature range 1200° to 1500°C. Oxide thicknesses were measured by ellipsometry, interferometry, and profilometry. The two materials behaved similarly, exhibiting parabolic behavior for short times (up to 100 min) followed by decre…
Summary The adsorption of Zn 2+ , Pb 2+ , Cu 2+ , Co 2+ , and Cd 2+ (M 2+ ) by soils was measured at concentrations ranging from 10‐ 7 to 10‐ 2 M in 10‐ 3 to 10‐ 2 M CaCI 2 . Exchange between Ca 2+ and M 2+ , and solubility products [M 2+ ][OH − ] 2 indicate that M 2+ is not precipitated as hydroxide but is adsorbed o…
An extensive infrared investigation of the CO/Rh/Al2O3 system has revealed the presence of eight different CO/Rh species including two which have not been observed previously. It has been shown that Rh loading on an alumina support is more critical than reduction temperature in effecting infrared spectral changes in t…