Materials Literature
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The molecular field theory of nematics is rephrased in density functional language. The free energy in the nematic state is expressed as a functional expansion around the isotropic state in powers of the nematic order parameters P l and the fractional density change eta at the isotropic-nematic transition. The crucial…
The authors present a band calculation for antiferromagnetic MnTe. MnTe is found to be a semiconductor with an indirect energy gap of 0.35 eV. The density of states and reflectivity spectra are presented and compared with experiment. As a result of comparison they conclude that optical properties of MnTe can be descri…
The interactions of tetrakis(4-N-methylpyridyl)-porphine (H2TMpyP-4) and its copper(II), nickel(II), zinc(II), cobalt(III), iron(III), and manganese(III) derivatives with several nucleic acids have been investigated. Spectrophotometric titrations of H2TMpyP-4 and Cu(II)TMpyP-4 with the synthetic polymer poly(dG-dC) co…
A strong case is made to show that the $F$-type color centers in oxide crystals are qualitatively different from the color centers of alkali halides. A semiquantitative discussion is followed by the results of an $X\ensuremath{\alpha}$ self-consistent-field calculation for the $\ensuremath{\alpha}$-${\mathrm{Al}}_{2}$…
Both elastic and inelastic electron scattering have been used to characterize and investigate the electronic properties of As${\mathrm{F}}_{5}$-doped polyparaphenylene. Evidence is presented for the existence of a polaron state slightly above the top of the valence band at low doping levels. An increase in the doping…
The local translational structure of a two-dimensional colloidal liquid is observed by use of cross correlation of the intensity fluctuations of light scattered by the liquid through two different wave vectors. The utility of multidetector scattering in probing multipoint correlations in disordered phases is thereby d…
Abstract Three-dimensional diffraction patterns of monochromatic electromagnetic waves contain moving line singularities where the magnitude of the transverse field is zero, and its direction is therefore indeterminate. They are called disclinations, by analogy with the corresponding linear features in liquid crystals…
Abstract TANTALOY 61 METAL is a tantalum-tungsten alloy of high density. It was developed for use as a spring material or for other elastic parts which must operate under chlorinating or severe acid conditions. Its combination of mechanical and anti-corrosion properties has led to extensive use for chlorinator valve s…
The paper comprises a theoretical and experimental investigation into the impulse breakdown voltage-time characteristics of a spherical- particle-contaminated coaxial-cylinder gap in compressed SF6and SF6-N2mixture. The experimental work was carried out on a 25/70-mm diameter coaxial-cylinder gap with a 3.2-mm spheric…
The description of current-induced failures in thin film metallizations used in microelectronic devices should not be limited to electron wind arguments. Several failure mechanisms such as grain boundary grooving, thermotransport and electrotransport, may contribute to matter transport under conditions normally encoun…
Alternative sandwich-panel decorative films were investigated as replace ments for the polyvinyl fluoride currently used in aircraft interiors. Candidate films were studied for flammability, smoke emission, selected toxic gas emis sion, flame spread, and suitability as a printing surface for the decorative acrylic ink…
Abstract The use of binary systems as accelerators in the vulcanization of rubber has received considerable attention, since many of them in suitable combinations, have been shown to provide efficient vulcanization systems. Dogadkin and co-workers and Skinner and Watson reported mutual activation with a number of popu…
Abstract Es wurde der Einfluß der Temperatur auf die Hydratation des Monocalciumaluminats, CaO · Al 2 O 3 , mittels der Differentialcalorimetrie, der Bestimmung der zeitlichen Änderung der aus 1 H‐NMR‐Messungen zu ermittelnden Spin‐Gitter‐Relaxationszeit T 1 der Protonen sowie durch röntgenographische Charakterisierun…
The potentiostatic scratch method has been systematically applied to rank the pitting corrosion (PC) resistance of commercial and laboratory austenitic, superaustenitic, and extra low interstitial ferritic stainless steels in chloride solutions simulating the aggressivity of the human body and seawater. This technique…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTRole of higher triplet states in the anthracene-sensitized photoisomerization of stilbene and 2,4-hexadieneJack Saltiel, David E. Townsend, and Alan SykesCite this: J. Am. Chem. Soc. 1983, 105, 9, 2530–2538Publication Date (Print):May 1, 1983Publication History Published onl…
The sorption rate of swelling penetrants in glassy polymers has been considered as controlled both by the swelling kinetics and the penetrant diffusion through the swollen layer. The stress exerted on the glassy core at the moving boundary is the driving force for the swelling, and results from an osmotic stress and a…
The effect of microstructure on failure initiation of sodium beta″‐alumina solid electrolytes have been investigated by acoustic emission detection. Mode I failure initiation follows Weibull statistics with a modulus of about 2.5. The observed average critical current densities were 145 and 640 mA/cm −2 for large and…
SUMMARY A high‐resolution electron‐microscopic study of sodium β′″‐alumina, a polytype of the more‐widely‐studied sodium β‐ and β″‐alumina, has been undertaken using the 600 kV instrument at Cambridge University. Images revealed the loss of sodium‐containing planes, which had caused crystals to collapse and shear into…
In a previous paper[8] breakdown strengths of c-C4F8/SF6/CO gas mixtures in various proportions were reported for a 30mm rod-sphere gap under ac and impulse voltages. A mixture of 1% c-C4F8 + 59% SF6 + 40% CO exhibited higher dielectric strength than pure SF6 in the pressure range between 350 and 400 kPa. The present…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPerhydroazulenes. 4. 6-tert-Butyl-4-oxoperhydroazulene systemHerbert O. House, Peter C. Gaa, Joseph H. C. Lee, and Don VanDerveerCite this: J. Org. Chem. 1983, 48, 10, 1670–1678Publication Date (Print):May 1, 1983Publication History Published online1 May 2002Published inissu…