gem-Dialkoxylation of 2-acetylthiophenes and 2-acetylfurans

Reaction of 2-acetyl-substituted thiophenes and furans with alkyl nitrites in the presence of the corresponding aliphatic alcohols and hydrochloric acid leads to the formation of linear acetals of thienyl- and furylglyoxals, whose structure was established by IR, UV, NMR spectroscopy, and mass spectrometry methods. The main paths of the dissociation of the molecules under electron impact were established.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 772–775, June, 1987.     

Detection of the multiple spallation parameters and the internal structure of a particle cloud during shock-wave loading of a metal

The results of experiments on studying spallation and the ejection of particles from the surfaces of copper and lead samples are presented. A laser interferometry method is used to detect the particle cloud velocity and the multiple spallation parameters. Angular detectors are used to detect the depth profile of the particle cloud velocity dispersion and the structure of metal spallation.     

Mass spectrometry determination of the isotopic composition of uranium hexafluoride

An absolute method for the determination of isotopic composition of substances in multiple collector mass spectrometers was proposed. The detailed analysi of terms used in the method for the determination of the isotopic composition of uranium hexafluoride was given. Parabolic nature of occurring constant measurement error, obtained in theory, was proved by test data for ²³⁵U within a wide range of its concentrations. In order to use the method of measurements in practice, the registration of constant error, through linear discriminatory relations Δc _i (c _i ), preliminary determined using uranium hexafluoride with standard isotopic composition, was proposed. The advantages of the developed method in comparison with the traditional analysis procedures, applied at present, were considered.     

Kerr Lens Mode-locked Operation of Yb:KYW Laser

Using a modified ABCD-matrix approach accounting for nonlinear refraction in active medium,the ranges of cavity parameters that provide a mode-locking of Yb∶KYW-laser in usual z-fold cavity configuration are determined.Taking the cavity parameters that provide a most efficient mode locking and based on fluctuation model,a numerical simulation of laser operation is performed.In the calculations the side-band pump power of 6W at 982 nm is used in 1 cm length KYW crystal with 1 cm×0.005 cm beam cross section.Calculations show that self-starting operation is possible with these parameters and dispersion compensation allows for bandwidth-limited ultrashort pulse generation.The shortest pulse duration was determined to be about 200 fs with self-starting buid-up time of 130 μs.Such a built-up time is comparable and even shorter than that one for the lasers with semiconductor saturable absorbers.The region of negative dispersion provided by prism pair for a stable ultrashort pulse generation was determined to be (-17000～-42000)fs2.     

Solvability of Implicit Complementarity Problems

In this paper, a new notion of exceptional family of elements (EFE) for a pair of functions involved in the implicit complementarity problem (ICP) is introduced. Based upon this notion and the Leray–Schauder Alternative, a general alternative is obtained which gives more general existence theorems for the implicit complementarity problem. Finally, via the techniques of continuous selections, these existence theorems are extended to the multi-valued implicit complementarity problems (MIPS).