Materials Literature
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Abstract The isothermal degradation of high cis ‐1,4‐polyisoprene vulcanizates having different crosslinking structures was investigated by a measurement of weight loss of sample, IR and NMR, gel permeation chromatography (GPC), and gas chromatography (GC). The degradation behavior of dicumy peroxide‐cured sample is s…
Studies have been carried out on the characteristic optical textures exhibited by mixtures of nematic and cholesteric compounds, namely, N-(P-propoxybenzylidene)p-pentylaniline (PBPA) and cholesteryl ethyl carbonate (CEC). Many of the textures are metastable and undergo a slow transformation at room temperature in the…
The different ways in which gold alloys can deteriorate are described. The principal alloys discussed are gold-copper, gold-silver and gold-copper-silver. Examples of South American gold alloys from Colombia and Panama are used to illustrate the different types of corrosive attack. Some problems related to the conserv…
A Miniaturized Disk Bend Test (MDBT) capable of extracting postirradiation mechanical behavior information from disk-shaped specimens no larger than those used for transmission electron microscopy has been successfully developed. Finite element analysis is performed to convert the experimentally measured data into use…
The depolarization behavior of ordered and disordered lead scandium-tantalate (PST) ceramics has been studied by Byer-Roundy and Chynoweth method. A sharp decrease of the spontaneous polarization takes place in a narrow temperature range very close to the Curie temperature Tc for the ordered PST materials. For the dis…
"Les Capteurs en Instrumentation Industrielle." Optica Acta: International Journal of Optics, 30(11), p. 1503
Contrast-enhancing agents for demonstrating abnormalities of the blood-brain barrier may extend the diagnostic utility of proton nuclear magnetic resonance (NMR) imaging. "TES," a nitroxide stable free radical derivative, was tested as a central nervous system contrast enhancer in dogs with experimentally induced unil…
Piezoelectric compositions Pb(MnuNbvNiwTixZry)O3 where u+v+w+x+y = 1.0 were studied by means of X-ray powder diffractometry, scanning electron microscopy and thermal analytical techniques. These studies showed that Mn is incorporated into the tetragonal lattice as trivalent ions at the Ti, Zr octahedral (B) sites.
Abstract The stability of common soil minerals found in Ultisols was studied relative to their natural soil solution composition. The mineralogy of the clay fraction (<2 µm) ranged from 22 to 60% in kaolinite, 0 to 20% in gibbsite, 17 to 57% in hydroxyinterlayered vermiculite (HIV), and 1 to 12% in quartz. Ion acti…
The effects of alloying elements on σ phase precipitation in δ–γ duplex phase stainless steels have been studied with particular emphasis on the partitioning of alloying elements. Sigma phase precipitation occurred mainly through the eutectoid decomposition of δ into σ and γ phases. The concentrations of Cr, Mo, W, an…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSinglet molecular oxygen in micellar systems. 1. Distribution equilibriums between hydrophobic and hydrophilic compartmentsPlato C. Lee and Michael A. J. RodgersCite this: J. Phys. Chem. 1983, 87, 24, 4894–4898Publication Date (Print):November 1, 1983Publication History Publ…
Films of polystyrene or polymethyl methacrylate were cast on oxidized silicon substrates, then detached by the application of gas or water pressure from the back side of the film through a hole in the substrate. Critical detachment pressures showed good repeatability and could be used to calculate the work of adhesion…
Abstract The formation and structure of chars produced on heating of cellulose, lignin, and wood have been investigated by FTIR and CP/MAS 13 C‐NMR, and the results have been discussed in conjunction with parallel permanganate oxidation studies reported before. These data show that when cellulose is heated for 5 min w…
Porous, multicomponent silicate gels were heated in flowing and pressurized ammonia. These treatments resulted in dense, homogeneous oxynitride (O‐N) glasses which were synthesized at low temperature (∼1000°C) without melting. The O‐N glasses exhibited increased microhardness and glass‐transition temperature and alter…
Exponentially growing cells of Bacillus subtilis and Escherichia coli were Gram stained with potassium trichloro(eta 2-ethylene)platinum(II) (TPt) in place of the usual KI-I2 mordant. This electron-dense probe allowed the staining mechanism to be followed and compared with cellular perturbations throughout the stainin…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotocatalytic conversion of primary amines to secondary amines and cyclization of polymethylene-.alpha.,.omega.-diamines by an aqueous suspension of titanium(IV) oxide/platinumSeiichi Nishimoto, Bunsho Ohtani, Tadao Yoshikawa, and Tsutomu KagiyaCite this: J. Am. Chem. Soc.…
Etude de l'influence de la structure du fer colloidal sur la croissance de la diatomee marine cotiere Thalassiosira pseudonana
The stability relations of prehnite and epidote were experimentally determined for the bulk composition of Ca2Al2FeSi3O12(0H) + excess H2O using conventional hydrothermal apparatus and solid oxygen buffer techniques. Three starting materials were used: (I) mixtures of natural prehnite and hematite, (II) mixtures of sy…
Filiform corrosion occurs on painted metals and cannot be prevented by conventional corrosion inhibitors. In order to better understand the corrosion phenomena, the literature was reviewed and the characteristics exhibited by filiform corrosion on different metals were cataloged. Calculations were performed to select…
The phase diagram of a one-dimensional many-electron system with site-diagonal electron-phonon(e-p) coupling and short-ranged inter-site electron-electron(e-e) repulsion as well as intra-site one is studied within the mean field theory for electrons and in the adiabatic limit for phonons. The theory covers the whole r…