Reaction of dimethyl(chloromethyl)chlorosilane with trimethylsilyl derivatives of l-phenyl-2-acetyl- and 1-phenyl-2-trifluoroacetylhydrazines

Conclusion The reaction of dimethyl(chloromethyl)chlorosilane with the phenylhydrazone of 1-triraethylsiloxyethanone proceeds with initial trans-silylation and subsequent formation of (O Si)-chloro[2-(1-phenyl-2-acetylhydrazino)methyl]diraethylsilane. The analogous reaction with the phenylhydrazone of 1-trimethylsiloxy-2-trifluoroethanone terminates at the trans-silylation step.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2781–2783, December, 1986.     

Impact of acoustic oscillations on thermal tornado stability

This paper presents physical modeling of thermal tornado under lab conditions. For the tested range of 0÷300 Hz, selective frequencies were discovered which facilitate the tornado decay. Data analysis was complemented by velocity profile measurement using LDV system LD-05M. The results on velocity pulsation at selected points were recalculated into coefficient of correlation between velocities and function cos(2πfΔt _i ) describing the acoustic oscillations. In the theoretical part of this paper, we present solution of dispersive equation of Euler’s model and resulting boundary of stability for tornado existence. Satisfactory agreement between experiment and calculation has been observed.     

High-Temperature Heat Capacity of Germanates Pr2Ge2O7 and Nd2Ge2O7 within 350–1000 K

Pr2Ge2O7 and Nd2Ge2O7 were obtained via solid-phase synthesis from Pr2O3 (Nd2O3) and GeO2 with multistage firing in air within 1273–1473 K. A temperature effect on molar heat capacity of the oxide compounds was measured with a differential scanning calorimetry. Their thermodynamic properties were calculated from the C _P = f(T) dependences.

     

Nonlinear optical limiters of pulsed laser radiation based on carbon‐containing nanostructures in viscous and solid matrices

Results of the study of optical limiters of pulsed laser radiation based on nonlinear effects in carbon nanostructures placed into viscous and solid matrices are presented. A nonlinear optical limiting was studied by nanomaterials based on multi‐wall polyhedral carbon nanostructures (astralens) placed in a sol–gel matrix. Similar studies for single‐wall and multi‐wall carbon‐containing nanotubes placed in polymer matrices with various viscosities were performed. No additional mechanism of optical limiting due to electron structure of single‐wall carbon‐containing nanotubes at their introduction into viscous and solid composite media was found. An influence of polymer matrix composition containing carbon nanotubes (CNTs) on a threshold and ratio of attenuation of laser radiation was demonstrated. The best limiting characteristics were observed at placing CNT into polymethylsiloxane matrix. An effect of “self‐healing” of a medium after laser radiation passage through high viscous liquids was obtained. The high parameters of nonlinear optical limiting (the threshold of limiting 10^?5 J, ratio of attenuation 10³) achieved for the composite material CNT (HiPCO High‐Pressure Carbon Monoxide) and carbon nanofibers in high viscous and solid polymethylsiloxane media allow the design of protective filters for laser radiation operating in wide spectral range. Copyright © 2014 John Wiley & Sons, Ltd.     

Acyl group carriers. XVII. Synthesis of analogues of 3′-dephosphocoenzyme A with modified pyrophosphate groups

The synthesis has been performed of dephosphocoenzyme A, 4′,4″-di-0-(2′,3′-9-isopropylideneadenosineuronyl)pantethine, and of 4′,4″-di(2′,3′-isopropylideneadenosineuronylamino)-4′,4″-dideoxypantethine from 2′,3′-0-isopropylidene adenosineuronic acid, using as condensing agents the tert-butyl dicarbonatepyridine and the N,N′-dicyclohexylcarbodiimide-N-hydroxysuccinimide systems, respectively.