967 research outputs found

    Land, Captial & Power in Russia

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    People's Deputy: Yuri D. Chernichenko

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    This repository item contains a single article of the Publication Series, papers in areas of particular scholarly interest published from 1989 to 1996 by the Boston University Institute for the Study of Conflict, Ideology, and Policy. The volume this article belongs to is titled "Soviet People's Deputies speak"

    A frustrated-Lewis-pair approach to catalytic reduction of alkynes to cis-alkenes

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    Frustrated Lewis pairs are compounds containing both Lewis acidic and Lewis basic moieties, where the formation of an adduct is prevented by steric hindrance. They are therefore highly reactive, and have been shown to be capable of heterolysis of molecular hydrogen, a property that has led to their use in hydrogenation reactions of polarized multiple bonds. Here, we describe a general approach to the hydrogenation of alkynes to cis-alkenes under mild conditions using the unique ansa-aminohydroborane as a catalyst. Our approach combines several reactions as the elementary steps of the catalytic cycle: hydroboration (substrate binding), heterolytic hydrogen splitting (typical frustrated-Lewis-pair reactivity) and facile intramolecular protodeborylation (product release). The mechanism is verified by experimental and computational studies

    Semantic representation of the conceptual entity religion in english (on the material of the book “Тhe Da vinci code” by dan brown)

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    У статті розглядаються питання мовної репрезентації ідеї RELIGION в англійській мові. Проаналізовано семантичну структуру фрейму на позначення релігійних понять в англійській мові.The paper deals with the questions of language representation of the conceptual entity RELIGION in English. The structure of the frame used to depict the religious experience of a man in English has been analyzed

    Measurement of xF3xF_3 and F2F_2 Structure Functions in Low Q2Q^2 Region with the IHEP-JINR Neutrino Detector

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    The isoscalar structure functions xF3xF_3 and F2F_2 are measured as functions of xx averaged over all Q2Q^2 permissible for the range of 6 to 28 GeV of incident neutrino (anti-neutrino) energy at the IHEP-JINR Neutrino Detector. The QCD analysis of xF3xF_3 structure function provides ΛMSˉ(4)=(411±200)\Lambda_{\bar{MS}}^{(4)} = (411 \pm 200) MeV under the assumption of QCD validity in the region of low Q2Q^2. The corresponding value of the strong interaction constant αS(MZ)=0.1230.013+0.010\alpha_S (M_Z) = 0.123^{+0.010}_{-0.013} agrees with the recent result of the CCFR collaboration and with the combined LEP/SLC result.Comment: 11 pages, 1 Postscript figure, LaTeX. Talk given at the 7th International Workshop on Deep Inelastic Scattering and QCD (DIS 99), Zeuthen, Germany, 19-23 Apr 199

    Exploring structural and electronic effects in three isomers of tris{bis(trifluoromethyl)phenyl}borane: Towards the combined electrochemical-frustrated Lewis pair activation of H2

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    Three structural isomers of tris{bis(trifluoromethyl)phenyl}borane have been studied as the acidic com- ponent of frustrated Lewis pairs. While the 3,5-substituted isomer is already known to heterolytically cleave H2 to generate a bridging-hydride; ortho-substituents in the 2,4- and 2,5-isomers quench such reactivity through electron donation into the vacant boron pz orbital and steric blocking of the boron centre; as shown by electrochemical, structural and computational studies. Electrochemical studies of the corresponding borohydrides identify that the two-electron oxidation of terminal-hydrides occurs at more positive potentials than observed for [HB(C6F5)3]−, while the bridging-hydride oxidizes at a higher poten- tial still, comparable to that of free H2

    An Improved Shashlyk Calorimeter

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    Shashlyk electromagnetic calorimeter modules with an energy resolution of about 3%/sqrt{E (GeV)} for 50-1000 MeV photons has been developed, and a prototype tested. Details of these improved modules, including mechanical construction, selection of wave shifting fibers and photo-detectors, and development of a new scintillator with improved optical and mechanical properties are described. How the modules will perform in a large calorimeter was determined from prototype measurements. The experimentally determined characteristics of the calorimeter prototype show energy resolution of sigma_E/E=(1.96+-0.1)% \oplus (2.74+-0.05)%/sqrt{E}, time resolution of sigma_T = (72+-4)/sqrt{E} \oplus (14+-2)/E (ps), where photon energy E is given in GeV units and \oplus means a quadratic summation. A punch-through inefficiency of photon detection was measured to be \epsilon = 5*10^{-5} (\Theta >5 mrad).Comment: 29 pages, 21 figure

    Determination of the high-twist contribution to the structure function xF3νNxF^{\nu N}_3

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    We extract the high-twist contribution to the neutrino-nucleon structure function xF3(ν+νˉ)NxF_3^{(\nu+\bar{\nu})N} from the analysis of the data collected by the IHEP-JINR Neutrino Detector in the runs with the focused neutrino beams at the IHEP 70 GeV proton synchrotron. The analysis is performed within the infrared renormalon (IRR) model of high twists in order to extract the normalization parameter of the model. From the NLO QCD fit to our data we obtained the value of the IRR model normalization parameter Λ32=0.69±0.37 (exp)±0.16 (theor) GeV2\Lambda^2_{3}=0.69\pm0.37~({\rm exp})\pm0.16~({\rm theor})~{\rm GeV}^2. We also obtained Λ32=0.36±0.22 (exp)±0.12 (theor) GeV2\Lambda^2_{3}=0.36\pm0.22~({\rm exp})\pm0.12~({\rm theor})~{\rm GeV}^2 from a similar fit to the CCFR data. The average of both results is Λ32=0.44±0.19 (exp) GeV2\Lambda^2_{3}=0.44\pm0.19~({\rm exp})~{\rm GeV}^2.Comment: preprint IHEP-01-18, 7 pages, LATEX, 1 figure (EPS

    Performance of a fine-sampling electromagnetic calorimeter prototype in the energy range from 1 to 19 GeV

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    The fine-sampling electromagnetic calorimeter prototype has been experimentally tested using the 1-19 GeV/c tagged beams of negatively charged particles at the U70 accelerator at IHEP, Protvino. The energy resolution measured by electrons is Delta{E}/E=2.8%/\sqrt{E} + 1.3%. The position resolution for electrons is Delta{x}=3.1 + 15.4/sqrt{E} mm in the center of the cell. The lateral non-uniformity of the prototype energy response to electrons and MIPs has turned out to be negligible. Obtained experimental results are in a good agreement with Monte-Carlo simulations.Comment: Article is prepared for pdflatex using the class elsart. 13 pages, 9 figures in 11 PDF file
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