Materials Literature
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Abstract A recent method, which contains no adjustable parameters, is used to deconvolute the background intensity of inelastically scattered electrons from the XPS spectrum of silver in the 200–900 eV kinetic energy range. The inelastic background signal is found to match the measured spectrum in the energy regions b…
The eigensolutions of the Maxwell equations for light propagation in a perfect cholesteric liquid crystal are considered. They are Bloch waves having, in principle, infinitely many Fourier components. The relative amplitudes of these components are studied as a function of the angular frequency \ensuremath{\omega} and…
The structure of individual liposomes of both biological and synthetic amphiphiles is shown to be a single family of Dupin cyclides. Such a family consists of closed, parallel surfaces with a conjugate ellipse and hyperbola as the loci of the centres of curvature. The structure is established by comparing freeze-fract…
Abstract The polymerization of p ‐cresyl glycidyl ether catalyzed by imidazoles has been investigated as a model reaction for the polymerization of technical epoxy resins. The dependence of oligomer yield on time, temperature, and imidazole concentration, the distribution of the polymerization degrees, and the influen…
The tracer diffusion coefficients of 22 Na and 86 Rb and electrical conductivity were measured in a series of 0.56(Na, Rb) 2 S.0.44SiS 2 glasses as a function of the Rb/Na ratio and temperature. The data were used to calculate the Haven ratio as a function of the Rb/Na ratio. The Haven ratio at 149.6°C increases from…
Order–disorder transitions occurring in the Ag 2 SO 4 –K 2 SO 4 system were investigated by reaction kinetics, thermal analyses, X-ray diffraction, and electrical conductivity techniques. Solid–liquid and solid–solid phase diagrams are reported.The conductivity data in the high temperature phase of the solid resemble…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPicosecond photodissociation of six-coordinate iron(II) porphyrinsDabney White Dixon, Christine Kirmaier, and Dewey HoltenCite this: J. Am. Chem. Soc. 1985, 107, 4, 808–813Publication Date (Print):February 1, 1985Publication History Published online1 May 2002Published inissu…
Nitrooctaethylporphyrins readily undergo nucleophilic aromatic substitution in the presence of HCl or HBr. In the presence of methoxide, nucleophilic addition to give a porphodimethane occurs, followed by autoxidation to the methoxyporphyrin. Unlike the nitrated complexes, the chlorosubstituted porphyrins exhibit redo…
Experiments in which a long vertical, heated wire is surrounded by concentric annuli of a melt and its crystalline solid show that the convection state changes from a stable unicell surrounded by a stationary cylindrical solid–liquid interface, to a complex time-dependent flow surrounded by a rotating, helical solid–l…
We report the feasibility of x-ray scattering studies of freely suspended strands of discotic liquid crystals of triphenylene hexa-n-dodecanoate (HATH) and of hexa-alcoxy derivatives of triphenylene (HET11). With use of a pin and cup configuration, we are able to grow strands, which are stable for days, of diameter >…
Kristallines Silber(III)‐oxid , das bei −20°C längere Zeit beständig ist, wurde durch anodische Oxidation von AgCIO 4 , AgBF 4 oder AfPF 6 (nicht AgNO 3 ) in wäßriger Lösung erhalten. Definiertes Ag 2 O 3 war bisher nicht bekannt. Es interessiert als möglicher Bestandteil der Anoden in Zink/Silberoxid‐Primärzellen. Na…
An undisturbed site under forest cover near Breton, Alberta was chosen to study the characteristics of a typical Gray Luvisol. Smectite and to a lesser extent mica were dominant in the clay fraction of the Bt. This horizon contained higher levels of organic C, pyrophosphate-extractable Fe and Al and dithionite-citrate…
The root growth of an Al sensitive barley (Hordeum vulgare L.) was used to evaluate the influence of surface applied amendments on the properties of an acid subsoil. Soil columns were packed with 10 cm of A horizon over 45 cm of an acidic Bt horizon from a Gilpin silt loam. Prior to planting of the barley the columns…
We present the results of Monte Carlo simulations of the equation of state of hard ellipsoids of revolution with axial ratio's a/b = 3, 2.75, 2, 1.25, 0.8, 0.5, 0.3636 and 0.3333. We identify four distinct phases, viz. isotropic fluid, nematic fluid, ordered solid and plastic solid. In all cases the thermodynamic phas…
High resolution replica materials are routinely used in scanning electron microscopy. A systematic evaluating procedure for replica combinations is proposed which details fourteen points to be recorded. These points include quantitative and qualitative information useful when assessing a replica combination for a part…
In this study, the glass transition temperature is determined from thermal expansion measurements in a series of glass compositions prepared by bulk fusion of a phosphosilicate matrix to which oxides of boron, germanium, or arsenic are added. On a per‐molar basis, addition of boron was observed to be the most effectiv…
Abstract Research relevant to the understanding of polymer–metal adhesion led us to an oxygen Auger (KLL) study on metal oxide surfaces. This was done in order to analyse the ionicity and strength of ‘Lewis sites’ on oxide surfaces grown on metals as compared to their bulk metal oxide counterparts. Following some sugg…
A generalized model of plain woven fabric is proposed, based on a more realistic approximation of yarn bending behavior than that previously used. Peirce's rigid thread model is a special case. Approximate formulae for calculating the ratio of crimp height to thread spacing and weave angle are developed.
The intensity and spectrum of light scattered by a nematic liquid crystal of positive dielectric anisotropy (5CB) in the presence of an ac squarewave electric field have been measured. The results for the twist-bend mode agree well with the theory developed by the Orsay Group and lead to satisfactory values for elasti…
The differences in frictional forces acting between fabrics woven from filament yarns are dependent on the morphology of the fabrics and the rubbing direction. When one fabric is moved across a second stationary fabric and the projecting yarn waves of one of the fabrics is rubbed perpendicular to the yarn axes orienta…