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1.
S. V. Polosatkin A. V. Burdakov M. V. Ivantsivskiĭ V. S. Koĭdan V. K. Ovchar A. F. Rovenskikh V. V. Semionov M. G. Fedotov 《Plasma Physics Reports》2006,32(2):108-113
A multichannel Thomson scattering diagnostics for measuring the plasma parameters in the GOL-3 facility was designed and created
at the Budker Institute of Nuclear Physics of the Siberian Division of the Russian Academy of Sciences. The diagnostics operates
at the fundamental harmonic of a neodymium laser (1.06 μm) and allows one to perform measurements over a wide range of electron
temperatures and densities with high spatial and time resolutions. A special multipulse oscillator is developed that makes
it possible to perform up to 20 measurements of the plasma temperature and density over a period of 300 μs during one shot.
The laser used to generate probing radiation, the recording system, and the calibration procedure are described. Results from
measurements of the temporal evolution of the plasma density in the GOL-3 in different stages of the discharge are presented
to illustrate the system operation.
Original Russian Text ? S.V. Polosatkin, A.V. Burdakov, M.V. Ivantsivskiĭ, V.S. Koĭdan, V.K. Ovchar, A.F. Rovenskikh, V.V.
Semionov, M.G. Fedotov, 2006, published in Fizika Plazmy, 2006, Vol. 32, No. 2, pp. 128–133. 相似文献
2.
MARIÁN PERNÝ VLADISLAV KOLARIK L'UBO MAJESKÝ PAVOL MÁRTONFI 《Botanical journal of the Linnean Society. Linnean Society of London》2008,157(3):475-485
Cytogeographical variability within the Phleum pratense group in the Carpathians and adjacent part of Pannonian lowland, based on 132 populations analysed by flow cytometry, is described. Only diploid and hexaploid plants were detected among 635 samples from the studied area. Diploids were found to be less frequent (127 plants, 20%) than hexaploids (508, 80%). With the exception of the single pure diploid population, diploids always co-occured with hexaploids (30 localities, 22.7%). The majority of populations (101, 76.5%) consisted of hexaploid plants. Most mixed populations occur in the Western Carpathians (26). In the Eastern Carpathians, mixed populations are much rarer, with three populations in Ukraine and one in Romania. In the Southern Carpathians, only hexaploids occur. The conventional taxonomic concept of the two species, diploid P. bertolonii and hexaploid P. pratense , was followed in spite of their sympatric occurence. Distribution maps based on chromosome number data from previous studies and on ploidy level estimates are given for both species in the studied area. The pattern of different distribution of the two taxa within the Carpathians is discussed. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 157 , 475–485. 相似文献
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Dobretsov GE Gularian SK Sarkisov OM Gostev FE Petrukhin AN Titov AA Svetlichnyĭ VIu Syreĭshchikova TI 《Biofizika》2007,52(1):14-19
Processes accompanying the quenching of the fluorescent probe 4"-dimethylaminochalcone by hydroxyl groups of the proton-donor solvent 1-butanol have been studied. The kinetics of the deactivation of the excited state of 4"-dimethylaminochalcone has been monitored from the transition absorption spectra at a time resolution of 50 fs and fluorescence decay at a time resolution of 30 ps. The data obtained allow thinking that the next picture occurs in 1-butanol. At first stage, the 4"-dimethylaminochalcone molecule in its ground state forms a hydrogen bond with an alcohol molecule. At the second stage, the absorption of light quantum and corresponding rise of the dipole moment of 4"-dimethylaminochalcone take place, the initially existing hydrogen bond is retained. The third stage consists in the rearrangement of the 4"-dimethylaminochalcone solvation shell formed by alcohol dipole molecules due to an increase of the dipole of moment 4"-dimethylaminochalcone; this rearrangement takes an energy of about 24 kJ/mol, the arrangement time constant is close to 40 ps; the initial hydrogen bond is retained. The fourth stage involves processes that lead to fluorescence quenching; their time constant is about 200 ps. Taking into account that the quenching is a much slower process than the relaxation of the solvation shell, it was supposed that the quenching is not a direct consequence of the solvation shell relaxation or the existence of the hydrogen bond formed prior to excitation. Then the fluorescence quenching of 4"-dimethylaminochalcone can be accomplished through some other processes that are observed in other fluorescent molecules: (a) rearrangement of the initial hydrogen bond from a conformation that cannot quench the fluorescence of 4"-dimethylaminochalcone to a more "effective" conformation, (b) charge transfer between the excited of molecule 4"-dimethylaminochalcone and alcohol, or (c) solvent-induced twist of the 4"-dimethylaminochalcone amino group (its withdrawal from the molecule plane) by the action of the solvent. 相似文献
5.
The oligonucleotide composition of the E. coli genome and its sigma70-specific promoters has been analyzed. The promoter DNA was shown to contain mainly AT-rich hexanucleotides having functionally important physical properties such as the ability to form easily melting sites and induce the bending of the double helix. A comparative analysis of the electrostatic characteristics of hexanucleotides within the whole sequence of the E. coli genome and its promoter regions was made. Hexanucleotides possessing a more electronegative surrounding were found to predominate in the nucleotide sequence of the promoter DNA. 相似文献
6.
It has been shown that exposure to weak combined collinear magnetic fields (permanent component 42 mT; amplitude of alternating component 40 nT, frequency 3.7 Hz) or millimeter waves with a frequency of 36 GHz and power density of 100 mT/cm2 substantially stimulates the growth of the regeneration blastema in the tail fragment of planaria when the exposure to fields precedes the cutting of the planaria body. This effect is more clearly pronounced during the treatment of planaria with magnetic field. If the treatment with weak physical factors is carried out after the cutting of planaria, the effect of the field is two times less pronounced (exposure to magnetic waves) or is not evident at all (exposure to electromagnetic radiation). 相似文献
7.
A nonmonotonous dependence of luminescence intensity of aqueous solutions of 0.1 M glycine and its N-methyl derivatives on the number of methyl groups in the solute molecule was found. A correlation between luminescence intensities and optical density at the excitation wavelength of 300 nm was revealed. Possible causes of the phenomenon observed were analyzed. Among these are: luminescence of admixtures, intrinsic luminescence of dissolved molecules, and luminescence related to the formation of nanoscale complexes in solution. On the basis of the data, it is impossible to make a final choice between the three above-mentioned mechanisms of luminescence of aqueous solutions of glycine and its N-methyl derivatives. 相似文献
8.
Kreslavskiĭ VD Fomina IR Kosobriukhov AA Herbert SK Babykin MM Biel KY 《Biofizika》2007,52(2):277-286
The damaging effect of oxidative stress inductors: methyl viologen, benzyl viologen, cumene hydroperoxide, H2O2, menadion, and high irradiance on the photosynthetic apparatus of cyanobacterium Synechocystis sp. PCC 6803 in cells of the wild type strain and the methyl viologen-resistant Prq20 mutant with the disrupted function of the regulatory gene prqR has been investigated by measuring the delayed fluorescence of chlorophyll a and the rate of CO2dependent -O2 gas exchange. It has been shown that the damage to the photosynthetic apparatus in the Prq20 mutant as compared with the wild type was less in the presence of methyl viologen and benzyl viologen. Reasons for the enhanced resistance of the photosynthetic apparatus in the mutant Prq20 to methyl viologen and benzyl viologen are discussed. 相似文献
9.
A comparative study of the conformation dynamics of a series of heptapeptides: the human alpha-fetoprotein fragment LDSYQCT and its seven analogues has been conducted. The effect of the dielectric constant of medium on the dynamics of heptapeptide conformation is considered. It is shown that electrostatic interactions have a marked effect on several accessible conformations and the dynamics of the behavior of amino acid residues. 相似文献
10.
The fluorescence of the natural photosynthetic pigments beta-carotene (beta-K) and chlorophyll a (Chl) and their mixtures with bovine serum albumin (BSA) in different molar ratios has been studied. An increase in the fluorescence intensity in a pigment mixture-BSA complex was found. The highest possible (four- to sixfold) increase in the fluorescence intensity compared with fluorescence intensity of one-pigment BSA complexes BSA (beta-K) and BSA (Chl) was achieved at the ratio 11-27% beta-K/89-73% Chl in the BSA complex. A considerable overlap of fluorescence spectra of BSA (Chl) complex (lambda(max) at 690 nm) and BSA (beta-K) complex (lambda(max) at 684 nm) was observed. 相似文献