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Novel polyethylene‐ and polypropylene‐based electromagnetic wave shielding and absorbing composite materials with low combustibility, enhanced thermal and mechanical properties, containing graphite, grinded wood, and fire retardants, were developed and investigated. Flame‐resistance, thermal and mechanical properties of these materials was investigated. Electromagnetic wave reflection coefficients over the frequency range 20–40 GHz were measured; at moderate concentration (10–15%) of functional filler, reflection coefficient can be as low as −16 dB for PE and −11 dB for PP composite, respectively. Coke formation mechanism was investigated, the principal role in this process is attributed to aromatization and condensation of aromatic compounds with the formation of polycyclic aromatic systems, an important role of phosphoric acids in accelerating this process was found. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [ABSTRACT FROM AUTHOR]

Abstract A synthesis of olanzapine, 2-methyl-10-(4-methyl-1-piperazinyl)-4H-thieno[2,3-b][1,5]benzodiazepine, was carried out and the conditions for its tritium labeling were optimized to obtain a tritium-labeled olanzapine preparation with a specific radioactivity of 12 Ci/mmol. [ABSTRACT FROM AUTHOR]

Abstract A general algorithm is proposed for constructing coherent boundaries. This algorithm is based on the interrelation between the spatial coherence of structural fragments in nanoparticles and the geometric connection in the corresponding associated bundle. A local approach is used to describe the structure of coherent boundaries in zirconia nanoparticles. The inference is made that the models of structures thus obtained should be preferred over the models constructed in terms of the theory of coincident site lattice. [ABSTRACT FROM AUTHOR]

Abstract The principle of the correspondence of a nanoparticle structure to the locally minimal manifolds embedded in a fiber space that is determined by the E8 root lattice can be used as the basis for the structural theory of “ideal” nanoparticles. The keplerate structure can be defined as a substructure of the corresponding algebraic geometry construction that is mapped into a concentric combination of sphere subdivisions. For example, to a 110-vertex icosahedral keplerate there corresponds a combination of three sequential cross sections of the {5, 3, 3} polytope. A 260-vertex phantasmagorical fulleroid is determined by the subdivision into heptacycles and pentacycles of the combination formed by five cross sections of the {5, 3, 3} polytope. The structures of keplerate rods can be obtained by rolling the corresponding polytope along a specific direction. The rolling of the {3, 3, 5} decorated polytope specifies the structure of a rod composed of 561-atom giant icosahedral clusters. [ABSTRACT FROM AUTHOR]

Abstract A new method for measuring the flux density and fluence of fast neutrons in a RBMK core, using a threshold ionization fission chamber with a 238U radiator, and a computational-experimental method based on threshold chambers for fissioning of 238U with enrichment at least 99.999% are proposed. A method is proposed for taking account of the correction factors for the change in sensitivity of threshold fission chambers with and without screens on the basis of RBMK-1000 fast-neutron spectra determined experimentally by the activation method. [ABSTRACT FROM AUTHOR]

Abstract This paper reports on the results of rheological investigations into the kinetics of gelation of the sol-gel systems based on a water-alcohol solution of tetraethoxysilane (TEOS) modified by a number of metal salts and organic polyhydroxyl compounds, such as glycerol, poly(ethylene glycol) (PEG-300), and hyperbranched aliphatic complex polyol polyethers (HBP-49, HBP-64). It is demonstrated that, at a dispersed phase concentration of approximately 10 wt %, water-ethanol sol-gel systems containing 24 g/l of high-molecular additives possess a shear strength and are characterized by anomalous properties in their flow. The gelation time of sols in the presence of organic additives is affected by the ratio between the numbers of OH- hydrophilic and CH3 hydrophobic groups in the polymer molecule, the concentration of the introduced additive, and the electrolyte multivalence. The presence of metal salts enhances the structuring effect of polymers. [ABSTRACT FROM AUTHOR]

Abstract The structures of giant icosahedral close-packed clusters are considered in the framework of the local approach. A specific four-dimensional construction that consists of tetrahedra and octahedra and has symmetry of the {3, 3, 5} polytope is determined. It is demonstrated that the Pd561 cluster is an icosahedral twin of fragments of both the face-centered cubic lattice and the hexagonal close packing simultaneously. [ABSTRACT FROM AUTHOR]

Abstract It is demonstrated that the structural inhomogeneity of the nanostate is a fundamental property and can be adequately explained in terms of the algebraic geometry when the four-dimensional fiber space is chosen as a hypothetical praphase of a nanoparticle. Zirconia nanoparticles ZrO2 with coherent boundaries between their constituent fragments are treated as cross sections of this praphase by three-dimensional Euclidean hyperplanes. The monoclinic, tetragonal, and orthorhombic zirconia structures are assembled from the capped octahedra Z7 and the Bernal polyhedra Z8 and Z9 that are geometrical structural complexes (building blocks) of fluorite-like structures. The interrelated constructions of finite projective geometries are determined. These constructions make it possible to specify graphs of the Z7, Z8, and Z9 polyhedra and to simulate the corresponding ZrO2 phases as fiber bundles associated with one principal fiber bundle, namely, the ZrO2 praphase. A priori possible mutual transformations in zirconia are considered, and new structural forms of nanoparticles assembled from the Z7, Z8, and Z9 polyhedra are predicted. [ABSTRACT FROM AUTHOR]

Abstract Structural features have been identified for microcrystalline silicon carbide (c-SiC), and also for the amorphous analog (a-SiC) within the framework of molecular dynamics by the use of the empirical Tersoff potential. Detailed analyses have been performed for c-SiC on the crystallite, grain boundaries, and amorphous matrix. The amorphous matrix in c-SiC is more ordered than the amorphous structure in a-SiC. Careful studies have been made of the state densities in the two materials on the basis of an sp3s* tight-binding scheme. A possible mechanism has been proposed for the effects of homopolar bonds and other coordination defects on the electronic states and cohesion. The results are compared with those obtained by other researchers. [ABSTRACT FROM AUTHOR]

Abstract Structural features have been identified for microcrystalline silicon carbide (c-SiC), and also for the amorphous analog (a-SiC) within the framework of molecular dynamics by the use of the empirical Tersoff potential. Detailed analyses have been performed for c-SiC on the crystallite, grain boundaries, and amorphous matrix. The amorphous matrix in c-SiC is more ordered than the amorphous structure in a-SiC. Careful studies have been made of the state densities in the two materials on the basis of an sp3s* tight-binding scheme. A possible mechanism has been proposed for the effects of homopolar bonds and other coordination defects on the electronic states and cohesion. The results are compared with those obtained by other researchers. [ABSTRACT FROM AUTHOR]

The concept of nanostructure fragmentariness is discussed. The formation of structurally inhomogeneous nanoparticles should be considered a problem of irregular division of space. [ABSTRACT FROM AUTHOR]

The structural diversity of the nanoworld and its origin are analyzed. Consideration is given to different aspects of this problem, such as the nonequilibrium, coherence, hierarchic structure, fragmentariness, and generalized symmetry. The inhomogeneity of the structure of a nanoparticle and the structural diversity of the nanoworld are treated as a result of the self-organization of a nonequilibrium nonlinear multivariant system. [ABSTRACT FROM AUTHOR]

Organic–inorganic composites are synthesized by introducing a number of low- and high-molecular water-soluble polyhydroxyl compounds (with different molecular weights and different molecular structures) into sols based on tetraethoxysilane. The coatings on nickel substrates are prepared by adding chromium dioxide as a finely disperse filler to the soles. The rheological properties of the sol–gel systems synthesized are investigated, and the surface condition and the microstructure of the coatings formed are examined. The xerogels and the coatings are studied by differential thermal and X-ray powder diffraction analyses. [ABSTRACT FROM AUTHOR]

Abstract The classical concept of density is not very applicable to particles a few nanometers in size. It is shown that, when dealing with the continuous model representations, which are based on the operation of averaging over a volume element and are applied to nanoparticles, or when evaluating the specific physical quantities for nanoparticles, it is necessary to use singular functions. [ABSTRACT FROM AUTHOR]

The central solenoid is an intrinsic part of all present-day tokamaks and most spherical tokamaks. The spherical torus (ST) confinement concept is projected to operate at high toroidal beta and at a high fraction of the non-inductive bootstrap current as required for an efficient reactor system. The use of a conventional solenoid in a ST-based fusion nuclear facility is generally believed to not be a possibility. Solenoid-free plasma start-up is therefore an area of extensive worldwide research activity. Solenoid-free plasma start-up is also relevant to steady-state tokamak operation, as the central transformer coil of a conventional aspect ratio tokamak reactor would be located in a high radiation environment but would be needed only during the initial discharge initiation and current ramp-up phases. Solenoid-free operation also provides greater flexibility in the selection of the aspect ratio and simplifies the reactor design. Plasma start-up methods based on induction from external poloidal field coils, helicity injection and radio frequency current drive have all made substantial progress towards meeting this important need for the ST. Some of these systems will now undergo the final stages of test in a new generation of large STs, which are scheduled to begin operations during the next two years. This paper reviews research to date on methods for inducing the initial start-up current in STs without reliance on the conventional central solenoid. [ABSTRACT FROM AUTHOR]