Materials Literature
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We investigate in detail the initial susceptibility, magnetization curves, and microstructure of ferrofluids in various concentration and particle dipole moment ranges by means of molecular dynamics simulations. We use the Ewald summation for the long-range dipolar interactions, take explicitly into account the transl…
The properties of dense granular systems are analyzed from a hydrodynamical point of view, based on conservation laws for the particle number density and linear momentum. We discuss averaging problems associated with the nature of such systems and the peculiarities of the sources of noise. We perform a quantitative st…
Large scale computer simulations are presented to investigate the avalanche statistics of sand piles using molecular dynamics. We could show that different methods of measurement lead to contradicting conclusions, presumably due to avalanches not reaching the end of the experimental table.
Abstract Preparation of the conducting composites of polystyrene/expanded graphite via in situ polymerization and investigation of the conductive mechanism were carried out. They are characterized by high conductivity and a low percolation threshold. The electrical conductivity reached 10 −2 S/cm with 3.0 vol % expand…
The H5PV2Mo10O40 polyoxometalate in a polyethylene glycol solvent was effective for a series of aerobic oxidation reactions including oxydehydrogenation of alcohols and cyclic dienes, oxidation of sulfides and the Wacker reaction; the solvent-catalyst phase can be recovered and recycled.
Diluted magnetic semiconductors (DMSs), in which magnetic elements are substituted for a small fraction of host elements in a semiconductor lattice, can become ferromagnetic when doped. In this paper we discuss the physics of DMS ferromagnetism in systems with semiconductor heterojunctions. We focus on the mechanisms…
Measurements of x-ray emission and absorption spectra of the constituents of MgB$_2$ are presented. The results obtained are in good agreement with calculated x-ray spectra, with dipole matrix elements taken into account. The comparison of x-ray emission spectra of graphite, AlB$_2$, and MgB$_2$ in the binding energy…
Macromolecular brushes with a gradient of side-chain spacing along the backbone have been synthesized by the “grafting from” approach using atom transfer radical polymerization. A macroinitiator was prepared in two steps, first by conducting a gradient copolymerization of MMA and HEMA-TMS followed by transformation of…
Crystal structure of spinel compound CuIr$_{2}$S$_{4}$ was examined by powder X-ray diffraction for the insulating phase below the metal-insulator transition at $T_{MI}$ = 230 K. The superstructure spots are reproduced by considering the displacement of Ir atoms. A model for the ionic ordering of Ir$^{4+}$ and Ir$^{3+…
The current status and prospects of research on ferromagnetism in semiconductors are reviewed. The question of the origin of ferromagnetism in europium chalcogenides, chromium spinels and, particularly, in diluted magnetic semiconductors is addressed. The nature of electronic states derived from 3d of magnetic impurit…
Materials design of new functional diluted magnetic semiconductors (DMSs) is presented based on first principles calculations. The stability of the ferromagnetic state in ZnO-, ZnS-, ZnSe-, ZnTe-, GaAs- and GaN-based DMSs is investigated systematically and it is suggested that V- or Cr-doped ZnO, ZnS, ZnSe and ZnTe ar…
The interest in diamond windows for the application of high power radiation technology is increasing continuously due to its outstanding thermal and opto-electronic properties. In order to analyze the surface properties of very highly polished polycrystalline diamond in the sub-micrometer down to nanometer regime, two…
Cubic boron nitride films (c-BN) were prepared by sputtering of a hexagonal BN sintered target. The films obtained were characterized by scanning electron microscopy, Infrared absorption spectra and UV-visible transmission spectra. The UV photodetetor devices of c-BN films were fabricated by photolithographic techniqu…
The Co-Cr-Mo alloy is extensively used for tribological applications, including orthopaedic components in total joint replacements. High quality diamond-like carbon (DLC) coatings on metal/alloy substrates are of great interest as they are able to protect them from severe wear and thus prolong the life span of the com…
Abstract The synthesis and characterization of the fluoropolymers poly 1a – 1d and poly 2a – 2d with pendant hydroxyl groups were examined. The polyaddition of bis(epoxide)s [2,2′‐bis(4‐glycidyletherphenyl)hexafluoropropane and bisphenol A diglycidyl ether] with dicarboxylic acids (tetrafluoroterephthalic acid and ter…
The interaction between phthalocyanine (ZnPc) and poly(ethylene oxide) (PEO) in water has been studied by dynamic laser light scattering and transient absorption and fluorescence spectroscopies. After the addition of PEO, the intensity of the transient absorption at ca. 490 nm, arising from the triplet state of the no…
Abstract The effect of mercapto‐modified ethylene vinyl acetate copolymer (EVALSH) on the rheological and dynamic mechanical properties of acrylonitrile butadiene rubber (NBR) and ethylene vinyl acetate copolymer (EVA) blends was evaluated at different blend compositions. The addition of 5 phr of EVALSH in the blends…
Several model systems for the α-carbonyl proton abstraction reaction were studied at the DFT level to examine the role of hydrogen bonding interactions in the enzyme catalytic activity of acyl-CoA dehydrogenase. Each system contains the thioester portion of acyl-CoA (CH 3 CH 2 (C O)SCH 3 ) a weakly basic COO ⊖ represe…
The effects of Ce addition on the activity of Pt/Al 2 O 3 catalysts were investigated for the wet oxidation of phenol. Platinum was impregnated on γ-Al 2 O 3 by using two different precursors: one is anionic (i.e., H 2 PtCl 6 ) and the other is cationic (i.e., Pt(NH 3 ) 4 Cl 2 ). The Pt catalysts from the former showe…
The formation of carbonaceous condensates in the atmospheres of asymptotic giant branch (AGB) carbon stars and in the nebulae of post-AGB objects occurs in a chemical environment that also contains oxygen and nitrogen. The extent of incorporation of chemical groups containing these elements in carbonaceous solids will…