Materials Literature
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The gas transport of hydrogen, oxygen, nitrogen, carbon dioxide, and methane gases in a series of poly(aryl ether ketone)s was examined. The polymer membranes have a wide range of permeability coefficients and permselectivity coefficients, showing excellent gas-transport properties. The enhanced interchain interaction…
Pineapple leaf fiber (PALF) which is rich in cellulose, relatively inexpensive, and abundantly available has the potential for polymer reinforcement. The present study investigated the tensile, flexural, and impact behavior of PALF-reinforced polyester composites as a function of fiber loading, fiber length, and fiber…
The transport properties of carbon dioxide, water, and different organic solvents in bacterial poly(3-hydroxybutyrate) (PHB) at 30°C were investigated. CO2 sorption was measured by the gravimetric method using a recording microbalance at subatmospheric pressures. Results were adequately interpreted in terms of Henry's…
Wood fiber-reinforced composites were prepared from poly(hydroxybutyrate) (PHB) and poly(hydroxybutyrate-co-hydroxyvalerate) (PHB/HV) copolymers containing 9 and 24% valerate. The effects of fibers on crystallization were investigated. Thermomechanical pulp, bleached Kraft fibers, and microcrystalline cellulose filler…
Pineapple leaf fiber (PALF) which is rich in cellulose, relatively inexpensive, and abundantly available has the potential for polymer reinforcement. The present study investigated the tensile, flexural, and impact behavior of PALF-reinforced polyester composites as a function of fiber loading, fiber length, and fiber…
The synthesis, properties and applications of polypyrrole (PPy), a representative of conducting polymers, are reviewed. Chemical and electrochemical methods for the preparation of PPy and PPy films and the effect of the reaction conditions on the properties of the polymer produced are discussed. The mechanisms of elec…
A sonoluminescing bubble has been modeled as a thermally conducting, partially ionized, two-component plasma. The model shows that the measured picosecond pulse widths are due to electron conduction and the rapidly changing opacity of the plasma and that these mechanisms are also responsible for the absence of an “aft…
We present a systematical method for obtaining analytical long-range embedded-atom potentials based on the lattice-inversion method. The potentials converge faster (exponentially) than Sutton and Chen's power-law potentials (Philos. Mag. Lett. 61, 2480(1990)). An interesting relationship between the embedded-atom meth…
Dense periodic arrays of holes and dots have been fabricated in a silicon nitride–coated silicon wafer. The holes are 20 nanometers across, 40 nanometers apart, and hexagonally ordered with a polygrain structure that has an average grain size of 10 by 10. Spin-coated diblock copolymer thin films with well-ordered sphe…
BACKGROUND: Genetically modified cells have been used in several animal models for the in vivo delivery of therapeutic proteins. One of the problems encountered is early cell death after the implantation of cells. MATERIALS AND METHODS: To improve the survival of implanted cells, we have developed a system in which tr…
Particle conservation equations for electrons and positive ions, together with Poisson"s equation to account for space-charge effects on the electric field, have been solved for the electrode sheath regions of electric arcs. For thermionic cathodes and the anode, we find that the ambipolar diffusion approximation is g…
Electron scattering cross sections (elastic, rotational and vibrational excitation) for a number of atomic and (relatively) simple molecular systems are examined. Particular reference is made to the level of agreeement which is obtained from the application of the completely different measurement philosophies embodied…
We have performed a relativistic treatment at low energy of electron–argon scattering which includes both polarisation and dynamic distortion effects. Our results are in excellent agreement with the experimentally derived momentum transfer cross section and scattering length, as well as with very recent measurements o…
Diffusion of symmetric diblock copolymer chains in macroscopically oriented lamellar block copolymers are studied in a molecular dynamics simulation. Results for diffusion constant both parallel $D_\parallel$ and perpendicular $D_\perp$ to the lamellar planes are compared to results in the disordered one phase region.…
Animal fatty acid synthase (FAS; EC 2.3.1.85) is a homodimer of a multifunctional subunit protein and catalyzes the synthesis of palmitate from acetyl-CoA, malonyl-CoA, and NADPH. The subunit (Mr approximately 270,000) carries seven distinct component activities and a site for the prosthetic group 4'-phosphopantethein…
We have synthesized La0.83Na0.11MnO2.93 by heating La2O3 and MnCO3 in NaCl melt at 900 °C. The exact composition was arrived by analyzing each ion by an independent chemical method. The compound crystallized in a rhombohedral structure and showed an insulator-to-metal transition at 290 K. Epitaxial thin films were fab…
The transition-metal dichalcogenides (X = S or Se) and with a electron configuration have distorted and structures, respectively, with the Re(Tc) atoms in each layer forming parallelogram-shaped connected clusters (diamond chain). Ab-initio band-structure calculations were performed for and , and the hypothetical undi…
To study the shape formation process of carbon nanotubes, a string equation describing the possible existing shapes of the axis curve of multishell carbon tubes (MCTs) is obtained in the continuum limit by minimizing the shape energy. It is shown that there exists a threshold relation of the outmost and inmost radii t…
Many properties of glass-forming systems can be explained in terms of their multidimensional potential energy landscape. Here the total potential energy landscape of a small glass-forming system with periodic boundary conditions is determined numerically. An appropriate one-dimensional projection is introduced. It all…
First-principles calculations show that the defect pair $({2V}_{\mathrm{Cu}}^{\ensuremath{-}}+{\mathrm{In}}_{\mathrm{Cu}}^{+})$ in CuInS${\mathrm{e}}_{2}$ has an unusually low formation energy, due both to the relative ease of forming Cu vacancies $({V}_{\mathrm{Cu}})$ and to the attractive interactions between ${V}_{…