Materials Literature
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The S matrix is first introduced within the framework of the angular spectrum representation of wave fields interacting with linear dielectric bodies of arbitrary shape. By using some universal properties of the S matrix, a number of relations involving certain generalized reflection and transmission coefficients are…
The shapes of two- , four- , and five-dimensional linear and ring polymers, with and without excluded volume, are investigated numerically via Brownian dynamics. It is found that the asphericity of nonexcluded volume linear polymers is in agreement with theoretical predictions in all dimensions. Agreement with availab…
Abstract Imogolite, though achiral, forms cholesteric spherulites in the anisotropic phase as shown by the regular striations arranged in a swirl‐like or fingerprint pattern observed through a polarizing microscope. Electron microscopy revealed the raft‐like imogolite sheet floating in the anisotropic phase. The struc…
Hydrogenated amorphous carbon films with high contents of sp 3 bonds have been prepared by a glow-discharge-decomposition of CH 4 and H 2 mixture. The film thickness and the optical gap of the films were gradually reduce up to annealing at 350°C by the densification of the film; they rapidly reduce above 350°C. The hy…
The drapemeter is a useful method for characterizing the behavior of fabrics, and the drape coefficient has been empirically related to bending and shear stiffness. As part of a wider study of complex buckling, we have found that the geometric form of deformation can be related to two dimensionless groups, relating be…
Abstract The sorption and diffusion of a series of liquids in a segmented polyurethane have been studied to determine how the behavior is affected by the choice of solvent and the heterophase nature of the polymer. The polyurethane was composed of methylene‐di‐para‐phenylene isocyanate (MDI) butanediol, and poly(tetra…
Abstract Aqueous sodium polysulfide of composition in the range Na 2 S 2.0 to Na 2 S 4.6 undergoes autoxidation by either air or pure oxygen at temperatures of between 23 and 40 °C according to the equation [xxx] Iodometric determination, vibrational spectra and ion-pair chromatography showed that neither sulfate, sul…
Abstract The calculated carbon 1s (C1s) core energy‐level positions of PMDA‐ODA polymide and of its polyamic acid precursor are compared with the level positions inferred from XPS measurements. For the polyamic acid, calculation and experiment both yield a difference of approximately 1 eV between the carboxylic acid a…
Raman scattering and infrared absorption studies of ferroelectric SbNb${\mathrm{O}}_{4}$, antiferroelectric BiNb${\mathrm{O}}_{4}$, and the solid solution $({\mathrm{Sb}}_{1\ensuremath{-}x}{\mathrm{Bi}}_{x})\mathrm{Nb}{\mathrm{O}}_{4}$ for $0<x<1$ in the range 20-1200 ${\mathrm{cm}}^{\ensuremath{-}1}$ are report…
The dielectric constant of dipolar hard sphere mixtures is calculated from the analytic solution of the mean spherical approximation (MSA) and using Monte Carlo simulation. The MSA is solved using the factorization technique pioneered by Wertheim and Baxter and extended to nonspherical interactions by Blum. The simula…
SUMMARY Potassium was extracted from samples of 21 surface soils and nine subsoils using a calcium‐saturated cation exchange resin and concentrated HCI under reflux. Most of the important arable soils of England and Wales were represented in the samples. The two methods permitted determination of the amounts and rates…
Abstract A series of polyurethane block copolymers based on hydroxybutyl terminated poly(chloropropylmethyl‐dimethylsiloxane) and poly(tetramethylene oxide) soft segments of molecular weights 2100 and 2000, respectively, were synthesized. The hard segments consisted of 4,4′‐methylenediphenylene diisocyanate (MDI) that…
The authors investigate optical bistability in CdS, induced by photo-electronic non-linearities. Varying the photon energy and the temperature of the sample they find three different types of optical bistability. The switching times are always around 1 ns or below, notably 300 ps for dispersive optical bistability. Op…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFunctionalized Keggin- and Dawson-type cyclopentadienyltitanium heteropolytungstate anions: small, individually distinguishable labels for conventional transmission electron microscopy. 1. SynthesisJohn F. W. Keana and Marc D. OganCite this: J. Am. Chem. Soc. 1986, 108, 25,…
Abstract The XPS peak shape from inhomogeneous transition metals is studied theoretically under variation of the path length R travelled by the photoelectron in the solid, the XPS peak energy E p , and the particular metal M . The variation in peak shape is characterized by a single parameter D = A p / B which is the…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFunctionalized Keggin- and Dawson-type cyclopentadienyltitanium heteropolytungstate anions: small, individually distinguishable labels for conventional transmission electron microscopy. 2. ReactionsJohn F. W. Keana, Marc D. Ogan, Yixin. Lu, Michael. Beer, and J. VarkeyCite t…
Abstract New data are reported on the crystallization kinetics of potassium sulfate solutions in a laboratory‐scale continuous MSMPR cooling crystallizer. Population density distributions determined down to 1 μm by laser light scattering and sieve analysis are corrected for the effects of crystal agglomeration and sha…
Six cell-free extracts have been used to characterize the nature of DNA signals and trans-acting factors responsible for the transcription enhancement of the Bombyx mori fibroin gene. The upstream element of the fibroin gene involved in the enhancement can be divided into two regions. The proximal region, -72 to -32,…
The ligand L, which is ideally suited for octahedral coordination, forces this coordination geometry upon Pd11 in the diamagnetic complexes 1 (green) and 2 (blue) and also serves in 3 (orange-brown) as a tridentate ligand. In all three cases, however, the axial PdS bonds are significantly longer than the equatorial.
Six species of ruminal bacteria were surveyed for the phosphoenolpyruvate (PEP)-dependent phosphorylation of glucose. Selenomonas ruminantium HD4, Streptococcus bovis JB1, and Megasphaera elsdenii B159 all showed significant activity, but Butyrivibrio fibrisolvens 49, Bacteroides succinogenes S85, and Bacteroides rumi…