Materials Literature
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The angular intensity distribution of He beams scattered from compact clusters and from diffusion limited aggregates, epitaxially grown on metal surfaces, is investigated theoretically. The purpose is twofold: to distinguish compact cluster structures from diffusion limited aggregates, and to find observable {\em sign…
Abstract Dibutyrylchitin was prepared by treatment of krill chitin with butyric anhydride in the presence of perchloric acid as a catalyst of reaction carried out at 25 to 30°C. Dibutyrylchitin is easily soluble in several organic solvents, such as acetone, alcohols, methylene chloride, and dimethylformamide. Samples…
We have measured the nondipolar contribution to the Ar $1s$ photoelectron angular distribution over the 30--2000 eV electron-energy range. The nondipolar interaction results in a forward or backward asymmetry with respect to the photon beam. The asymmetry is directed backward near threshold, is symmetric near 230 eV,…
This study reports UV-photoemission (UPS) measurements made on boron nitride crystals and thin films. The materials examined are commercial grade c-BN powder and thin films of BN deposited with ion beam assisted e-beam evaporation and laser ablation. The thin film samples examined exhibited varying amounts of sp3 (cub…
By focusing on entire bubbles rather than films or vertices, a simple model is proposed for the deformation and flow of foam in which dimensionality, polydispersity, and liquid content can easily be varied. Simulation results are presented for the linear elastic properties as a function of bubble volume fraction, show…
Electro-optical characteristics related to the threshold behavior of liquid crystals when using the in-plane switching (IPS) mode were investigated with interdigital electrodes. In order to analyze the switching behavior of liquid crystals, an equation, which expresses the threshold transition, was derived using the c…
The Fukui function for a neutral atom is expressed as its LDA approximation plus a one-parameter gradient correction, and the resultant formula is numerically tested. Expressing hardness as a density functional involving this Fukui function, global hardness values are determined for several atoms. Estimates also are m…
An ab initio method for calculating electron-phonon coupling parameters is presented. The method is an extension of the plane-wave-based linear-response method for the calculation of lattice dynamics. Results for the mass enhancement parameter and the electron-phonon spectral function for Al, Pb and Li are presented.…
Understanding the effect of pressure on aluminosilicate glass and liquid structure is critical to understanding magma flow at depth. Aluminum coordination has been predicted by mineral phase analysis and molecular dynamic calculations to change with increasing pressure. Nuclear magnetic resonance studies of glasses qu…
We present pseudo-potential coefficients for the first two rows of the periodic table. The pseudo potential is of a novel analytic form, that gives optimal efficiency in numerical calculations using plane waves as basis set. At most 7 coefficients are necessary to specify its analytic form. It is separable and has opt…
Perlite of composition SiO 2 73.6%, Al 2 O 3 12.4%, Fe 2 O 3 1.25%, MgO 0.15%, Na 2 O 2.99%, K 2 O 4.18%, H 2 O + 3.17%, H 2 O - 0.2%, and found to contain 89.4% of amorphous phase and 10.6% of crystalline phase, the latter consisting of feldspars, biotite, quartz, magnetite and chlorite, was studied. Due to its large…
Phenomenological models of the "colossal magnetoresistance" manganites have emphasized a local picture for the Mn ion, and little attention has been given to the effects of Mn d -O p hybridization. We present self-consistent local spin-density electronic-structure studies that properly account for hybridization, and f…
In this paper the statistical mechanical properties are investigated of a simple analytical model which is based loosely on a cluster of atoms. The model has a phase transition from a solid-like to a liquid-like phase. Particular interest is paid to the dependence of the nature of this phase transition on the number o…
The morphology of epitaxial structures formed in solidification of liquid Au films on the Au(110) surface was studied by molecular dynamics simulation based on a many--body interatomic potential. The (1x2) reconstructed and smooth phase at the temperature T=500 K, as well as a deconstructed and rough phase of the Au(1…
Abstract Electrically conductive polypyrrole (PPy)/poly( p ‐phenylene terephthalamide) (PPTA) composite fibers have been prepared by continuous vapor phase polymerization at a speed of 0.5 ∼ 1.5 m/min. The main parameters have been examined, and the conducting fibers with the best properties of electrical conductivity…
Abstract Blends of polycarbonate (PC) with poly(butylene terphthalate) (PBT) were characterized using density measurements, DSC, IR, and TGA. Addition of PBT increases the density values of blends linearly. All the blends show a single glass transition temperature, indicating the miscibility of the two polymers in the…
Abstract To establish relationships among the blend composition, processing history, and the resultant properties of starch‐based thermoplastics, three varieties of corn starch: (1) Waxy Maize, (2) Native Corn, and (3) high‐amylose Hylon VII were extrusion‐blended with poly(ethylene‐vinyl alcohol) (EVOH) containing 56…
Abstract Viscosity and density of homogeneous one‐phase solutions (1 wt %) of polyethylenes with narrow molecular weight distributions ( M w = 2150, 15,520, 108,000, and 420,000) in n ‐pentane were determined at 398, 413, and 428 K over a pressure range from 20 to 60 MPa. Measurements were done with a special falling…
The use of molecular genetics to introduce both a metal ion binding site and a nitroxide spin label into the same protein opens the use of paramagnetic metalnitroxyl interactions to estimate intramolecular distances in a wide variety of proteins. In this report, a His-Xaa3-His metal ion binding motif was introduced at…
Mercury has perhaps the strangest behavior of any of the metals. Although the other metals in column IIB have an $hcp$ ground state, mercury's ground state is the body centered tetragonal $β$Hg phase. The most common phase of mercury is the rhombohedral $α$Hg phase, which is stable from 79K to the melting point and me…