Globally anisotropic high porosity silica aerogels

We discuss two methods by which high porosity silica aerogels can be engineered to exhibit global anisotropy. First, anisotropy can be introduced with axial strain (i.e. axial compression). In addition, intrinsic anisotropy can result during growth and drying stages and, suitably controlled, it can be correlated with preferential radial shrinkage in cylindrical samples. We have performed small angle X-ray scattering (SAXS) to characterize these two types of anisotropy. We show that global anisotropy originating from either strain or shrinkage leads to optical birefringence and that optical cross-polarization studies are a useful characterization of the uniformity of the imposed global anisotropy.     

Simulation of interaction between a rarefied gas jet and an obstacle by the methods of molecular dynamics

An efficient method of direct numerical simulation is proposed. The steady-state flow field generated by the impingement of a gas jet on a wall is studied as an example. The numerical results obtained during this study are in good agreement with the numerical solutions of other authors.     

Nucleophilic addition to acetylenes in superbasic catalytic systems: XV. Vinylation of 2-hydroxymethylfuran

2-Hydroxymethylfuran reacted with acetylene in superbasic catalytic systems MOH-DMSO (M = Na, K) under mild temperature conditions (75–85°C, 1–2 h), yielding 80% of 2-vinyloxymethylfuran. The product, as well as acetaldehyde acetals derived therefrom, turned out to be promising as modifiers for electrolyte in lithium-sulfur rechargeable batteries.     

Solid-phase oxidative halodecarboxylation of β-arylacrylic acids with the ceric ammonium nitrate—alkali halide system

The solid-phase oxidation of cinnamic, 4-methoxy- and 3,4-dimethoxycinnamic acids with Ce(NH₄)₂(NO₃)₆—MHal system leads to β-halostyrenes. Similar procedure in the absence of a metal halide results in a cleavage of the C=C bond giving the corresponding benzaldehydes. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 114–118, January, 2008.     

Electrochemical synthesis of niobium compounds in anodic dissolution of ferroniobium in methanol

Anodic dissolution of ferroniobium in anhydrous methanol in the presence of sodium methylate was studied. The possibility of recovering pure hexamethoxyniobate from the electrolyzate and its conversion into niobium methylate with an iron content not exceeding 0.01% was analyzed.     

Zur Bestimmung des St?rkegehaltes in der Gerste und in anderen Getreidearten

Ohne Zusammenfassung     

On the Development of Fundamentally New Organic Reagents

Based on an analysis of the processes of intramolecular signal transfer (the ordered motion of a quasiparticle, vibron) and structural isomerization, it was pointed out that, in principle, reagents of a new type can be developed with analytical effects fundamentally different from usual ones. The type of analytical response can vary depending on the molecular structure and intramolecular processes induced. General principles of the molecular design of systems of this kind are discussed.     

Gaussian Approximations in the Stochastic Theory of Spontaneous Ignition of Coal Particles

Stochastic models of the process of spontaneous ignition of coal particles are distinguished by a pronounced nonlinearity due to the Arrhenius approximation for the constant of the reaction rate and by a complex structure of the stochastic component (noise). We present models describing the dynamics of the distribution of this quantity. The models obtained consist of nonlinear ordinary differential equations, which are solved by numerical methods with the use of computer technologies.