Materials Literature
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Cooled target collection techniques were used to study the formation of volatile products when samples of Cr, Ti, IN‐738, 713C, NASA‐TRW VIA, and B‐1900 were exposed at elevated temperatures to oxidizing environments containing and . Samples were heated to 1050°C in 1 atm of slowly flowing oxygen, saturated with water…
Abstract X‐ray diffraction, electron microscopic, and petrographic techniques have been employed to study the mineralogy of four soils developed on the Indo‐Gangetic alluvium in northwestern India. Sand and silt fractions are dominated by primary quartz. Other minerals present in these fractions include muscovite, pla…
The relationship between the growth of ductile cracks in pressure-vessel steels and the acoustic emissions produced during crack extension has been investigated. It has been shown that in some circumstances it is possible to detect the initiation of ductile cracking in laboratory specimens of a pressurevessel material…
The effect of pressure and temperature on peak energy and shape, intensity, and luminescence lifetime of a series of alkaline earth compounds doped with Eu2+ has been measured. The results are analyzed in terms of a quantum mechanical single configuration coordinate model. The quenching of the luminescence cannot be e…
The width of dislocations in grain boundaries is calculated by minimizing the interfacial energy of the boundary and the strain field energy of the dislocations. The calculations indicate that models, assuming equilibrium grain boundaries to consist of characteristic low energy structures with, if necessary, superimpo…
The leading LMFBR control rod material, B 4 C, was examined by SEM, TEM, and X‐ray diffraction after irradiation up to 80 × 10 20 captures/cm 3 between 500° and 920°C. Bulk swelling was found to be the result of elastic and plastic strains, rather than dilation of the unit cell. Microcracking was observed and explaine…
From 1971 to 1975, inclusive, 594 pronghorns (Antilocapra americana) were drive trapped in Alberta; subsequently, 74 of these animals were transported to enclosures. Deaths attributable to capture myopathy (CM) occurred in 20 of the trapped pronghorns and in 17 of the pronghorns that were trapped and subsequently tran…
Abstract A general thermodynamic relation between the Gapon and the Vanselow cation exchange equilibrium constants is derived and is shown to be violated by the expressions given traditionally in the soil chemistry literature for the Gapon and the Vanselow selectivity coefficients. This result suggests that the select…
Dormant spores of Bacillus megaterium were found to contain approximately 850 pmol of coenzyme A (CoA) per milligram of dry weight. Of this total, less than 1.5% was acetyl-CoA, 25% was CoA-disulfide, 43% was in disulfide linkage to protein, and the remainder was the free thiol. Dormand spores of Bacillus cereus and C…
A weak line at 969 cm−1 (941 cm−1) in the Raman spectrum of vitreous silica is shown to be due to the Si–O stretch vibration of OH (OD) groups. A triatomic molecular model for this defect accurately predicts the observed deuterated frequencies for both the Si–O and the O–D stretch vibrations bound to network silicon a…
Unsaturated fatty acid monolayers on silica gel have been autoxidized, and the rate of fatty acid disappearance and products obtained from those membrane-like assemblies have been studied. Fatty acid monolayers consisting of pure linoleic acid, linolelaidic acid, and oleic acid were autoxidized at 60 C. The rates of a…
The stable configurations of a dislocation in an infinite random array of point obstacles are analyzed using the mathematical methods of statistical mechanics. The theory provides exact distribution functions of the forces on pinning points and of the link lengths between points on the line. The expected number of sta…
The basic electrochemical properties of electrodes are described. The influence of the preparation techniques on the photoelectrochemical behavior of the electrodes is reported. The results are discussed in view of applications in solar energy conversion systems.
By comparison of the E.S.C.A. valence band spectra recorded in the solid phase for polyacenes (benzene, naphthalene, anthracene, and tetracene) with gas phase results, important energy parameters (energy gap, work function) of these compounds have been obtained. The trends observed in the evolution of the main C1 s sh…
The structure, phase diagram and compression behavior of polyethylene are studied by X-ray diffraction up to 11 kbar and 300°C. Distinct diffuse scattering on the non-equatorial line is first observed for the hexagonal phase of oriented polyethylene, revealing conformational disorder of the molecule. The phase diagram…
Abstract Three homologous cofacial diporphyrins that have interplanar distances ranging from 6.4Å to 4.2Å have been synthesized. Their absorption and emission spectra revealed strong exciton coupling in the diporphyrin. Magnesium complexes of diporphyrins were studied and their application as a model for P700 photoact…
Magnetic properties of the compounds RMn2 and RMn23 (R=Y, Lu, Gd, and Th) were studied before and after hydrogen absorption. Hydrogen-induced transitions from Pauli paramagnetism to ferromagnetism were observed in YMn2, LuMn2, and Th6Mn23. The reverse effect, i.e., changes from ferromagnetism to Pauli paramagnetism, w…
Abstract Ultraviolet and Fourier‐transform infrared spectroscopy are used to characterize the chain conformation of 2,6‐dimethyl poly(phenylene oxide) (2MPPO) in compatible 2MPPO‐polystyrene (PS) blends. Blending with PS increases the intramolecular energy of the 2MPPO. Atactic PS induces a greater distortion from the…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructure of Poly(1,4-benzamide) SolutionsM. Panar and L. F. BesteCite this: Macromolecules 1977, 10, 6, 1401–1406Publication Date (Print):November 1, 1977Publication History Published online1 May 2002Published inissue 1 November 1977https://pubs.acs.org/doi/10.1021/ma60060a…
Abstract Polyurethane elastomers are a numerous group of polymeric materials of wide practical application. They are usually formed by polyaddition of diisocyanates with hydroxyl-terminated polyesters or polyethers in the presence of low molecular weight diols or diamines as chain extenders. One may consider urethane…