Application of the Benzoyl O-Protecting Group in the Synthesis of α,β-Dehydrotyrosine-containing Amides and Imidazolones

Russian Journal of Organic Chemistry - The use of O-benzoyl protection in the synthesis of N-benzoyl-α,β-dehydrotyrosine benzylamide, and the corresponding 4-imidazolone was studied. The...     

Multibeam cross-correlator for diagnostics of terahertz subpicosecond pulses and electron bunches

We present a scheme of multibeam cross-correlator which allows high-temporal resolution measuring of durations of picosecond and subpicosecond pulses of terahertz range.     

Dynamics of difference frequency radiation generation in the field of few-cycle laser pulse propagating in GaAs crystal with domain structure

We consider the process of generation of difference frequency in a GaAs crystal with periodic domain structure during propagation of a few-cycle laser pulse in the crystal in the regime of weakly expressed chromatic dispersion. Method of lines is used to obtain numerical solution to the system of coupled nonlinear differential equations in partial derivatives describing the evolution of the electric field of a few-cycle laser pulse in GaAs crystal both with periodic and aperiodic domain structure. It is shown that employing GaAs crystal with domain structure allows controlling the instantaneous frequency of broadband pulse radiation at difference frequency.     

Static and noise characteristics of nanocomposite gas sensors

Thin film gas sensors based on nanocomposite In₂O₃·Ga₂O₃·SnO₂ (70:20:10) have been manufactured by the high-frequency magnetron sputtering method. The technological cycle of sensor fabrication processes is described. Sensitivity of the prepared sensors at the temperature of working body 250°C and low-frequency noises within the 1–300 Hz range were investigated. The response of sensors to vapors of ethanol and acetone was investigated using resistive and noise methods. It is shown that the value of the sensitivity measured by the noise method exceeds the value of sensitivity measured by the resistive method. Sensors show appreciable sensitivity to the ethanol vapors already at working body temperature 150°C. Sensors can be used for the detection of low concentrations of ethanol vapors. The monotonous increase in the sensitivity of these sensors with increase in the ethanol and acetone vapors content allows applying nanosensors also for fast determination of gases concentration in air.     

Improvement of the Raman-Nath approximation for the resonant Kapitza-Dirac scattering

On the basis of the well-known Raman-Nath approximation, we have obtained a new analytical form for the amplitude of the resonant Kapitza-Dirac scattering of an atom in the field of counter-propagating laser pulses. Comparison of the obtained formula with that in the Raman-Nath approximation shows that the former describes, in addition to coherent diffraction, also channeling of atoms in a periodic field of counter-propagating laser pulses.     

Synthesis of Some Heterocyclic Compounds from Enamines of 3-Acetylfuran-2(5 H)-ones

The interaction of different 3-acetylfuran-2(5H)-ones (1, 4) with dimethylformamide dimethyl acetal (DMF/DMA) has been investigated, and the condensed furopyridine system 3 was obtained. By means of interaction of compounds 4 and DMF/DMA via the 3-acetylfuran-2(5H)-one enamines, the heterocyclic substituted furanones are obtained. The condensation of 3-acetyl-4,5,5-trimethylfuran-2(5H)-one (1a) with veratraldehyde was realized. Through the interaction of 1a with malononitrile and further intramolecular condensation of the product, 6-amino-dihydroisobenzofuran-5-carbonitrile was also synthesized.     

Systematization of cross sections for the production of residual nuclei on separated tin isotopes in reactions induced by various-energy protons

Cross sections for the production of residual nuclei on the isotopes ^{112,118,120,124}Sn irradiated with 0.66-, 1.0-, 3.65-, and 8.1-GeV proton beams were investigated. A ten-parameter semiempirical formula was used to systematize the cross sections in question. A comparative analysis of parameter values obtained at different proton energies was performed.     

On a Class of <Emphasis Type="Italic">L</Emphasis>-Wiener-Hopf Operators

By replacement in the definition of the convolution operator of Fourier transform by a spectral transform of a selfadjoint Sturm-Liouville operator on the axis L, the concepts of Lconvolution and L-Wiener-Hopf operators are introduced. The case of the reflectorless potentials with a single eigenvalue is considered. A relationship between the Wiener-Hopf and L-Wiener- Hopf operators is established. In the case of piecewise continuous symbol the Fredholm property and invertibility of the L-Wiener-Hopf operator are investigated.     

Asymptotic Properties of the Density of Particles in $$\beta $$-Ensembles

We extend recent results on the asymptotic equipartition property for the density of n particles in \(\beta \)-ensembles, as n tends to infinity. We prove the large deviation principle of the log-density for a general potential and the mod-Gaussian convergence in the classical examples.