排序方式: 共有14条查询结果,搜索用时 62 毫秒
1.
Abdurashitov JN Gavrin VN Girin SV Gorbachev VV Ibragimova TV Kalikhov AV Khairnasov NG Knodel TV Kornoukhov VN Mirmov IN Shikhin AA Veretenkin EP Vermul VM Yants VE Zatsepin GT Bowles TJ Nico JS Teasdale WA Wark DL Cherry ML Karaulov VN Levitin VL Maev VI Nazarenko PI Shkol'nik VS Skorikov NV Cleveland BT Daily T Davis R Lande K Lee CK Wildenhain PW Khomyakov YS Zvonarev AV Elliott SR Wilkerson JF 《Physical review letters》1996,77(23):4708-4711
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D. N. Abdurashitov E. P. Veretenkin V. N. Gavrin V. V. Gorbachev T. V. Ibragimova A. V. Kalikhov I. N. Mirmov A. A. Shikhin V. E. Yants V. I. Barsanov A. A. Dzhanelidze S. B. Zlokazov S. Yu. Markov Z. N. Shakirov B. T. Cleveland 《Physics of Atomic Nuclei》2007,70(2):311-318
The activity of an artificial neutrino source based on 37Ar was measured by a specially developed method of directly counting 37Ar decays in a proportional counter. This source was used to irradiate the target of the SAGE radiochemical gallium—germanium neutrino telescope at the Baksan Neutrino Observatory (Institute for Nuclear Research, Russian Academy of Sciences, Moscow), whereupon the measurements were performed at the Institute of Reactor Materials (Zarechny, Sverdlovsk oblast, Russia). The method used to prepare gaseous samples for measurements in proportional counters and the counting procedure are described. The measured activity of the 37Ar neutrino source is 405.1 ± 3.7 kCi (corrected for decays that occurred within the period between the instant of activity measurement and the commencement of the irradiation of Ga target at 04:00 Moscow time, 30.04.2004). 相似文献
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J. N. Abdurashitov V. N. Gavrin S. V. Girin V. V. Gorbachev T. V. Ibragimova A. V. Kalikhov N. G. Khairnasov T. V. Knodel I. N. Mirmov A. A. Shikhin E. P. Veretenkin V. M. Vermul V. E. Yants G. T. Zatsepin T. J. Bowles W. A. Teasdale D. L. Wark J. S. Nico M. L. Cherry B. T. Cleveland R. Davis Jr. K. Lande P. S. Wildenhain S. R. Elliott J. F. Wilkerson 《Physics of Atomic Nuclei》2000,63(6):943-950
The solar-neutrino-capture rate measured by the Russian-American Gallium Experiment on metallic gallium during the period from January 1990 to December 1997 is (67.2 ?7.0?3.0 +7.2+3.5 ) SNU, where the uncertainties are statistical and systematic, respectively. This result represents a 7σ depression in the neutrino flux in relation to the predicted standard-solar-model rates. The experimental procedures used and data analysis are presented. 相似文献
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OG Khvostenko ZS Yarullina NM Shishlov VE Rusin 《Rapid communications in mass spectrometry : RCM》1999,13(12):1091-1097
A correlation between the energies of electronic singlet transitions in benzodiazepines and their biological activity, which was revealed earlier by means of negative ion mass spectrometry with resonance electron capture, has been verified with a UV absorption spectroscopy investigation. Also, it has been noted that the energies of electronic singlet transitions in benzodiazepines are close in value to the ionization energies of atoms Cs, Rb, K, Na, Li and Tl, the cations of which are known to play an important role in nerve cell excitation processes. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
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J. N. Abdurashitov E. P. Veretenkin V. M. Vermul V. N. Gavrin S. V. Girin V. V. Gorbachev P. P. Gurkina G. T. Zatsepin T. V. Ibragimova A. V. Kalikhov T. V. Knodel I. N. Mirmov N. G. Khairnasov A. A. Shikhin V. E. Yants T. J. Bowles W. A. Teasdale J. S. Nico J. F. Wilkerson B. T. Cleveland S. R. Elliott 《Journal of Experimental and Theoretical Physics》2002,95(2):181-193
We present measurements of the solar neutrino capture rate on metallic gallium in the Soviet-American gallium experiment (SAGE) over a period of slightly more than half the 22-year solar cycle. A combined analysis of 92 runs over the twelve-year period from January 1990 until December 2001 yields a capture rate of 70.8 ?5.2 +5.3 (stat) ?3.2 +3.7 (sys) SNU for solar neutrinos with energies above 0.233 MeV. This value is slightly more than half the rate predicted by the standard solar model, 130 SNU. We present the results of new runs since April 1998 and analyze all runs combined by years, months, and bimonthly periods beginning in 1990. A simple analysis of the SAGE results together with the results of other solar neutrino experiments gives an estimate of (4.6±1.2)× 1010 neutrinos cm?2 s?1 for the flux of the electron pp neutrinos that reach the Earth without changing their flavor. The flux of the pp neutrinos produced in thermonuclear reactions in the Sun is estimated to be (7.6 ± 2.0) × 1010 neutrinos cm?2 s?1, in agreement with the value of (5.95±0.06)×1010 neutrinos cm?2 s?1 predicted by the standard solar model. 相似文献
7.
V. V. Gorbachev J. N. Abdurashitov T. J. Bowles M. L. Cherry B. T. Cleveland R. Davis Jr. S. R. Elliott V. N. Gavrin S. V. Girin P. P. Gurkina T. V. Ibragimova A. V. Kalikhov N. G. Khairnasov T. V. Knodel K. Lande I. N. Mirmov J. S. Nico A. A. Shikhin W. A. Teasdale E. P. Veretenkin V. M. Vermul D. L. Wark P. S. Wildenhain J. F. Wilkerson V. E. Yants G. T. Zatsepin 《Physics of Atomic Nuclei》2002,65(12):2156-2160
The solar neutrino capture rate measured by the Russian-American Gallium Experiment on a metallic gallium target SAGE during the time from January 1990 through December 2000 is 77.0 ?6.2 ?3.0 +6.2 +3.5 SNU, where the uncertainties are statistical and systematic, respectively. The experimental procedures and data analysis are presented. 相似文献
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J. N. Abdurashitov V. N. Gavrin V. L. Matushko J. S. Nico A. A. Shikhin A. K. Thompson I. E. Veretenkin V. E. Yants 《Physics of Atomic Nuclei》2007,70(1):133-139
We discuss the development of a spectrometer based on full energy absorption using liquid scintillator doped with enriched
6Li. Of specific interest, the spectrometer is expected to have good pulse height resolution, estimated to lie in the range
10–15% for 14-MeV neutrons. It should be sensitive to flux rates from 10−6 cm−2 s−1 to 106 cm−2 s−1 above a threshold of 500 keV in an uncorrelated γ background of up to 104 s−1. We have constructed a pilot version of the detector using undoped liquid scintillator, and we report its present status.
The detector’s efficiency is determined by the volume of the scintillator (∼1.21) and is estimated to be 0.2–0.5% for 3-MeV
neutrons. The good pulse height resolution is achieved by compensation of the nonlinear light yield of the scintillator due
to the use of optically separated segments, which collect scintillations from each recoil proton separately. We demonstrate
here the response of the detector to neutrons from a Pu-α-Be source, whose energies range up to 10 MeV. Initial testing indicates a low threshold (≈600 keV) and good spectral response
after requiring a multiplicity of three segments. Such a spectrometer has applications for low-background experiments in fundamental
physics research, characterizations of neutron flux in space, and the health physics community.
The text was submitted by the authors in English. 相似文献
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Non-primitive LiCl aqueous electrolyte solutions were studied at 1.0, 5.0 and 10.0 M concentrations by molecular dynamics simulations. It was observed that the ion hydration structure is progressively lost with increasing concentration. The ions are aggregated in small clusters at C = 1.0 M. However, at this concentration, two large clusters were detected that are an initial step in an aggregation process. At C = 5.0 M, the highly unstable ion clustering seems to correspond to an intermediary state between low concentration states with poor aggregation and states where the ions are highly aggregated, as observed at C = 10.0 M where almost all the ions are clustered in one cluster. This cluster does not present a crystal-like structure. The high solubility of LiCl in aqueous solutions can consequently be explained as a result of the large radii difference between the anion and the cation that results in the instability of the ionic aggregates, which makes the formation of crystal seeds difficult. 相似文献
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The structure and hydration of insulin-like growth factor 1 and an inactive mutant lacking the C region have been investigated in aqueous solution by molecular dynamics simulation. The overall structures of the two polypeptide resemble those determined by NMR spectroscopy. The deletion of the C region in the wild polypeptide introduces structural stability in the mutant, leading to a better definition of the secondary structure elements. A detailed hydration analysis was performed using the radial distribution functions and energy distributions. The backbone of the mutant is in general more solvent accessible than the wild polypeptide backbone. The structural rearrangements induced in the mutant led to changes in the solvent exposition of Tyr24 and Tyr60, which are residues important for ligand—receptor complex formation. Tyr24 exhibited a similar degree of solvent exposition in both IGF-I and in the mutant; however, its hydroxyl group in the wild polypeptide is better solvated than in the mutant. Tyr60 was found to be solvent exposed in the wild protein, while in the mutant the involvement of its hydroxyl group in intramolecular hydrogen bonds led to it being buried away from the solvent. 相似文献