Diffraction Radiation of an Ultrarelativistic Charge in the Region of High Frequencies

Diffraction radiation of a charged ultrarelativistic particle passing near the edge of a target of finite width and thickness is considered. A solution is derived for the frequencies higher than that of plasma. It is shown that the spectral density of the radiated energy for high-energy particles ranges to higher-than-plasma frequencies. An estimation of the total radiation loss is made.     

RESPONSE RATE AND NOISE CHARACTERISTICS OF A BiSb METAL-SEMIMETAL CONTACT THERMOELECTRIC DETECTOR FOR THE MILLIMETER WAVE RANGE

The paper considers analytical and experimental results on the relative noise temperature and the thermal time constant of thermoelectric detectors with a point BiSb metal-semimetal contact in the 8-mm wave range.     

High resonant reflection of a confined free space beam by a high contrast segmented waveguide

High resonant reflection of a free space wave from a deeply corrugated slab waveguide is shown to take place in the case of a focused free space beam under normal incidence. It is described as a result of a strong intra-guide coupling coefficient allowing the coupled wave to be closely localized under the incident beam, therefore to interfere with it with high contrast effects. The coupled mode inspired analysis gives the possibility of optimizing the resonant structure; it is related and compared with the photonic crystal vision of the same functional structure to which it confers more intelligibility.     

Aziridinyl ketones and their cyclic anils. 11. Fluorine-containing photochromes

Chalcones with fluorine-containing groups were converted to ,-dibromides and then to cyclic aziridinyl anils. The introduction of an electron-acceptor trifluoromethylsulfonyl group leads to a significant, although smaller as compared with the nitro group, bathochromic shift of the minimum of the reflection spectrum. Fluorine-containing substituents decrease appreciably the dark-decolorization time of the aziridinyl anils.See [1] for Communication 10.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1179–1184, September, 1991.     

Question of the mechanism of the formation of 5-hydrazino-tetrazole from 5-diazomethylazotetrazole in acidic media

The heating of the hydrate of 5-diazomethylazotetrazole in an aqueous medium led to the isolation, for the first time, of 5-hydroxymethylazotetrazole — the proposed intermediate product in the isolation of 5-hydrazinotetrazole from 5-diazomethylazotetrazole in acidic media. It was established that 5-hydrazinotetrazole is not formed when 5-hydroxymethylazotetrazole is treated with hydrochloric acid under different conditions. In this connection, an improved reaction mechanism, not including 5-hydroxymethylazotetrazole as an intermediate compound, was proposed. It was shown that not all of the 5-diazomethylazotetrazole enters into the reaction with water. The proposition was expressed that the product which did not enter into the reaction is the Z-isomer.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1351–1353, October, 1992.     

Synthesis of stereoisomeric alkyl- and phenyl-substituted 5-cyanopiperidine-3,4-diols

-Hydroxy--[N-(2-cyanoethyl)amino]ketones were obtained by the reaction of methyl- and phenyl-substituted 2-acyloxiranes with 3-alkylaminopropionitriles. Treatment of the products with sodium tert-butoxide gave stereoisomeric 5e-cyanopiperidine-3,4-diols, the three-dimensional structures of which were established by means of spectral data, as well as by means of isomerization and oxidation with periodic acid.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1207–1211, September, 1986.     

Synthesis of 2-dialkylaminomethyltetrahydrofuran-3-ols

The reaction of esters of 4-R-3-methyl-2,3,4,5-diepoxyvaleric acids with secondary amines leads to the formation of esters of 4-R-5-dialkylamino-4-hydroxy-3-methyl-2,3-epoxyvaleric acids. The reduction of the latter with lithium tetrahydroaluminate and the cyclization of the reduction products in the presence of p-toluenesulfonic acid has given 2-dialkylaminoethyltetrahydrofuran-3-ols, the methiodides of which possess ganglion-blocking activity.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1443–1446, November, 1973.     

Cardenolide glycosides ofCheiranthus allioni. XV. Glucocheiranthoside

Another new cardenolide glycoside has been isolated from the plantCheiranthus allioni Hort., and has been named glucocheiranthoside. Its chemical structure has been established as 3-(4-O--D-glucopyranosyl--D-gulmoethylpyranosyloxy)-14-hydroxy-19-oxo-5,14-card-20(22)-enolide.State Scientific Center for Drugs, Ukraine, 310085, Kharkov, USSR. ul. Astronomicheskaya, 33. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 269–271, March–April, 1994.     

Structure of cucumarioside G1 — A new triterpene glycoside from the holothurianCucumaria fraudatrix

A new triterpene glycoside — cucamarioside G₁ — has been isolated from the Pacific Ocean holothurianCucumaria fraudatrix. On the basis of physicochemical characteristics and the results of chemical transformations, its structure has been established as 16-acetoxy-3-[O-(3-O-methyl--D-xylopyranosyl)-(1 3)-O--D-glucopyranosyl-(1 4)--D-quinovopyranosyl-(1 2)-(4-O-sulfato--D-xylopyranosyloxy)]-holosta-7,24-diene.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 244–248, March–April, 1985.     

Molecular Polarizability of Organic Compounds and Their Complexes: XLVIII. Molar Volumes of Benzene Derivatives in Solutions at Infinite Dilution,Their Additivity,and Correlation with the Dipole Moments and Kerr Constants

Extrapolation formulas were derived for determination of the molar volume of a solute at infinite dilution. This quantity is stable to solvent replacement and additive with respect to increments of substituents in polysubstituted benzenes. The molar polarization and molar Kerr constant of a solute can be expressed through the molar volumes of the solute at infinite dilution and of the solvent. Replacement of the molar volume in the calculation formulas by the quantity calculated by the additive scheme considerably reduces the experimental time required for determining the dipole moments and Kerr constants of compounds in solution.