求解复杂湍流的非线性涡黏性系数模型和代数应力模型

非线性涡黏性系数模型和代数应力模型联系了线性涡黏性系数湍流模型和完整的微分 雷诺应力模型.随着它们受到日益关注,其形式也越来越多样化.本篇综述的目的是对这些模 型加以总结并比较它们之间的共同点及不同之处,指出它们与完整微分雷诺应力模型之间的 关系,以及相对于线性涡黏性系数模型而言它们在预报流场上所具有的优势.     

Interaction of Aluminum/Cobalt Alloys with Liquid Gallium/Indium Eutectic

Al/Co alloys with different element ratios were studied by X-ray diffraction analysis, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The surface propagation of components of the Ga/In eutectic was studied in situ by energy-dispersive spectroscopy in the microscope chamber, and their propagation rate was estimated. It decreases with increasing Co content. Interaction of the Al/Co alloy with the liquid Ga/In eutectic was compared to that of the previously studied Al/Ni and Al/Fe alloys.     

Composite Materials with 2D Graphene Structures: Applications for Hydrogen Energetics and Catalysis with Hydrogen Participation

The work presents the results of studies concerning preparation of graphene-like nanomaterials by graphite oxide reduction, preparation of nickel-graphene catalysts, magnesium-graphene, and carbon-graphene composites. Optimum conditions for preparing these materials and their functional characteristics are determined.     

Reactions of β-Ketophosphonates and Enamine Phosphonates with Electrophilic Reagents

Abstract

The direction of the reactions of β-ketophosphonates and enamine phosphonates strongly depends on the structure of substrates and electrophiles. Regio- and stereoselectivity on the reaction of anionic P-ketophosphonates depends on the nature of cation and solvent. The yield of O-products increases substantially when going from alkylation to acylation, and in particular to phosphorylation.     

Processes e<Superscript>+</Superscript>e<Superscript>−</Superscript> → π<Superscript>0</Superscript>(π<Superscript>0</Superscript>′) γ in extended NJL model

The processes of electron-positron annihilation into π⁰γ and into π′(1300)γ are considered within an extended NJL model. The intermediate vector mesons ρ ⁰, ω ρ′(1450), and ω(1420) are taken into account. The latter two mesons are treated as the first radial excited states. They are incorporated into the NJL model by means of a polynomial form factor. Numerical predictions for the cross-sections of these processes are received for the center-of-mass energies below 2 GeV. Our results for the π⁰γ production are in agreement with experimental data obtained in the energy region 600–1020 MeV.     

Mechanochemical synthesis of nanocrystalline nickel-molybdenum compounds,their morphology and application in catalysis: I. Effect of the Ni: Mo atomic ratio on the structure and properties of nickel-molybdenum compounds prepared under mechanochemical synthesis conditions

Mechanochemical activation in high-energy planetary activators was used for the preparation of highly dispersed nickel-molybdenum compounds. Nickel hydroxocarbonate [NiCO₃ · 2Ni(OH)₂ · nH₂O] and ammonium paramolybdate [(NH₄)₆Mo₇O₂₄ · 4H₂O] were chosen as starting compounds. The effect of the Ni: Mo atomic ratio on the composition and structure of products formed in the process of mechanochemical activation followed by calcination was studied. It was found that, at the Ni: Mo atomic ratios of 1.0 and 1.4, the mechanically activated product after calcination at 520°C contained 70–100% β-NiMoO₄, which is a stable phase at temperatures lower than 180°C.     

Features of the Hydrogenation of Magnesium with a Ni-Graphene Coating

Russian Journal of Physical Chemistry A - The kinetics of the hydrogenation of magnesium composites with graphene-like material (GLM) on which nickel particles are deposited (Ni/GLM) and...     

Diazoalkanes in the Reactions with Dialkyl (Thio)-Phosphites

Abstract

The photochemical, thermo-catalytical and thermal reactions of diazoalkanes with dialkyl (thio)phosphites were studied.

Thus, the photolysis of dimethyldiazomalonate and methyl-diazoacetate with dialkyl(thio)phosphites gives P-H insertion products only upon triplet-sensitized conditions (i), whereas diphenyldiazomethane gives P-H insertion products upon direct photolysis as well (ii). The investigation of 31 the reaction mechanism is based on CIDNP ³¹P method. The catalytical reactions (iii) are a convenient method of preparing (thio)phosphonates.     

Synthesis of Phosphorylated Derivatives of Enamino-Carbonyl Compounds

Abstract

The reactions of enaminocarbonyl compounds (1) with phosphorylisocyanates have been investigated. Experiment established that the reactions with the participation of amino group and (or) C-2 atom form respectively ureas (2) and (or) their vinylogs (3) depending on the structure (1) i.e. the reactions proceed in two competitive directions.