Electro-acoustic sounding of the atmosphere

This paper presents the results of measurement of the electrical field generated by a high-power acoustic signal in the atmosphere (electro-acoustic sounding). The radiated acoustic power was about 1 kW. The acoustic-signal frequency varied linearly within the interval 17–21 Hz with a period of 8 min. The electric field was registered by a -shaped antenna. The results of processing of the electric-field records for a part of sessions indicate the presence of an electric response with frequency close to the acoustic-signal frequency. The signal amplitude at the input of the receiving device was 0.1–1 µV.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 48, No. 1, pp. 33–37, January 2005.     

Enantiospecific synthesis of carbapentostatins

In this paper we describe enantioselective syntheses of (+)-carbapentostatin (8) and its cyclopentyl analogue 12b. A new and efficient one-pot, two-step preparation of aldehyde 15 has been developed, based on the borane reduction of N-Pf-protected L-aspartic acid gamma-methyl ester (13) and Swern oxidation of the resulting alcohol. Homologation to diester 18 and ring formation by Dieckman cyclization, followed by reduction and dehydration steps, afford the 4-amino-1-cyclopentenemethanol derivative 22. Hydroboration and oxidation transform this compound stereospecifically into aminocyclopentanol 26, the key aminocyclitol component for an asymmetric synthesis of (+)-carbapentostatin.     

Photoluminescence Property of Co3O4 Nanowires

Co3O4 nanowire arrays are fabricated by electrodeposition with following heat-treatment in atmosphere ambient. Photoluminescence is investigated at 295K. In the experiment, when increasing the excitation light wavelength from 260 nm to 360 nm, two kinds of emissions corresponding to the increasing excitation light wavelength are observed. One of them alters the excited emission position, another keeps its emission position. The distinct behaviour of excited emissions related to the increasing excitation wavelength indicates that the mechanism of them must be different. According to the experimental comparison and first-principle calculation, the two kinds of emissions are discussed.     

具有粗糙核的Marcinkiewicz积分交换子在齐型Herz-Morrey空间上的有界性

建立了一类具有粗糙核的Marcinkiewicz积分交换子在齐型Herz-Morrey空间上的有界性.