Materials Literature
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By introducing a set of auxiliary equations representing a many-body system, we have derived an extension of the Kohn-Sham scheme for the density functional theory. These equations consist of a Kohn-Sham-type equation determining single-particle orbitals and an eigen-value equation for an effective many-body problem.…
A series of calculations on MgB2 and related isoelectronic systems indicates that the layer of Mg(2+) ions lowers the non-bonding B "pi" (p_z) bands relative to the bonding "sigma" (sp_xp_y) bands compared to graphite, causing sigma --> pi charge transfer and sigma band doping of 0.13 holes/cell. Due to their two dime…
The physical mechanisms for damage formation in graphite films induced by femtosecond laser pulses are analyzed using a microscopic electronic theory. We describe the nonequilibrium dynamics of electrons and lattice by performing molecular dynamics simulations on time-dependent potential energy surfaces. We show that…
The correlation between prepatterned catalyst film thickness and carbon nanotube (CNT) growth by selective area chemical vapor deposition (CVD) was studied using Fe and Ni as catalyst. To eliminate sample-to-sample variations and create a growth environment in which the film thickness is the sole variable, samples wit…
Natural fiber–reinforced polyester matrix composite materials are evaluated both for strength performance and cost. The flexural strength of composites fabricated with untreated chopped natural fibers is comparable only to the performance of low-strength wooden agglomerates and plywood. Nevertheless, it is shown here…
Copolymers of aniline and N-ethylaniline were prepared by chemical oxidation with ammonium peroxodisulphate in aqueous acidic medium under nitrogen atmosphere. The products have been characterized by solubility, spectroscopic method, and electrical conductivity measurement. The solubility and spectroscopic analysis su…
Hybrid composites were made using oil palm empty fruit bunch (EFB) and glass fibres (GF) as reinforcing agents in polypropylene (PP) matrix. Three types of coupling agents were incorporated in the composites, i.e. maleic anhydride–modified polypropylene (commercial name Epolene, E-43), polymethylene (polyphenyl isocya…
M ferrites (M = Ni and Cu) were prepared for the CO 2 decomposition reaction. The mechanisms of reduction and oxidation of M ferrites were investigated by thermogravimetric analysis and X-ray diffraction experiments. Cu ferrite showed excellent redox properties compared to those of Ni ferrite. Cu ferrite lost its oxyg…
The Peierls stress for a [111]-screw dislocation in bcc Tantalum is calculated using an embedded atom potential. More importantly, a method is presented which allows accurate calculations of the Peierls stress in the smallest periodic cells. This method can be easily applied to ab initio calculations, where only the s…
T(3)-gauge model of defects based on the gauge Lagrangian quadratic in the gauge field strength is considered. The equilibrium equation of the medium is fulfilled by the double curl Kroner's ansatz for stresses. The problem of replication of the static edge dislocation along third axis is analysed under a special, tho…
Depending on the temperature, the C70 solid crystallizes in several structures. At high temperature (T > 340K), the ellipsoidal C70 molecule rotates freely in all directions and may be treated as a uniform thick spherical shell with inner and outer radii as the minimum and the maximum distance of C-atom from the cente…
We calculate the pyrocoefficient, static dielectric susceptibility profiles and its thickness dependence of ferroelectric thin films. Also, the temperature dependences of above quantities have been calculated. For the calculations we use Landau phenomenological theory, leading to Lame equations. These equations subjec…
PEG-diacrylamide was synthesized and utilized to make materials for tissue engineering. Acrylamide groups readily react with thiol groups, and peptides containing a single thiol group were coupled to the PEG-diacrylamide in aqueous solution at room temperature in about 2 h. If only a portion of the acrylamide groups w…
Abstract In this work a morphological description of poly(vinyl alcohol) (PVA)/poly(vinyl acetate) (PVAc) incompatible blends was carried out combining scanning electron microscopy, epifluorescence microscopy, and fluorescence microspectroscopy, and using anthracene and fluorescein probes dissolved in the polymer blen…
Abstract The crystallization behavior of polyamide 66 under high pressure up to 2500 bar was investigated by the use of dilatometric and calorimetric techniques in nonisothermal and isothermal conditions. The solid–solid Brill transition is detected from the evolution of the specific volume in the PVT diagram. The var…
Two new vanadoselenites, [SeV(3)O(11)](3)(-) and [Se(2)V(2)O(10)](2)(-), were synthesized by reacting SeO(2) with VO(3)(-). Single-crystal X-ray structural analyses of [(n-C(4)H(9))(4)N](3)[SeV(3)O(11)].0.5H(2)O [orthorhombic, space group P2(1)2(1)2, a = 22.328(5) A, b = 44.099(9) A, c = 12.287(3) A, Z = 8] and [[(C(6…
Abstract The influence of vinyl ester/styrene network structure on thermal and mechanical properties was investigated. The crosslink density of the resins was altered by changing the molecular weight of the vinyl ester oligomer and by varying the amount of styrene used during the crosslinking reaction leading to varia…
An irreversible trans→cis isomerization of the imino group occurs during the irradiation of the new ferrocenyl Schiff-base polychlorotriphenylmethyl radical 1 by light. Low-temperature ESR investigations of frozen solutions revealed that the cis isomer exists as the (cis-1)2 dimer with strong antiferromagnetic interac…
A number of bacteria have been identified that aggravate corrosion of metals such as carbon steels, cast irons, stainless steels, aluminum alloys, and copper alloys. These are classified as aerobic and anaerobic according to their ability to grow in the presence or absence of air. They survive under a wide range of te…
Supported, air stable, and reusable hydroformylation catalysts have been prepared by immobilizing dinuclear rhodium(II) complexes bearing ortho-metalated arylphosphane ligands on amorphous silica and mesoporous MCM-41 supports by phosphane tethers. The oligosilsesquioxane model complex of the catalytic site 1 has been…