624 research outputs found

    Influence of Shear Deformation on Carbon Onions Stability under High Pressure

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    The influence of shear deformation on carbon onions stability under high pressure up to 45 GPa was investigated in a Shear Diamond Anvil Cell (SDAC) by the Raman spectroscopy and the Transmission Electron Microscopy (TEM). At shear less then 40 degrees the carbon onions are stable up to 30 GPa. Biger shear deformation leads to increasing of size and destruction of the onions and to formation of sp3 C-C bonds. At pressure exceeded 45 GPa shear deformation leads to diamond-like carbon (DLC) formation. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3501

    Structure of TiAlN Reactive Sputtered Coatings

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    The Raman spectra, X-ray diffraction and hardness of the TiAlN films co-deposited on the steel substrates by reactive sputtering from Ti and Al targets in a mixture of N2 + Ar gas with two magnetrons at room temperature have been studied. From Raman spectra it is found that the position of high-frequency bands in vibrational spectra was located at 700-730 cm 1 or in the region of 830 850 cm 1 depending on the deposition parameters whereas it is not exceed 630 cm 1 from TiAlN of NaCl structure. It is found the two-phase structure of coatings: a small quantity of NaCl-type structure of TiAlN (TiN) and the disordered structure of the chains of polyhedra [TiNx] with x = 5 and x = 4. The chains of polyhedra [TiNx] with x = 4 are mainly formed at large discharge power of Al(Ti) target or at small content of N2 gas. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2492

    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

    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

    The polymer phase of the TDAE-C60_{60} organic ferromagnet

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    The high-pressure Electron Spin Resonance (ESR) measurements were preformed on TDAE-C60_{60} single crystals and stability of the polymeric phase was established in the PTP - T parameter space. At 7 kbar the system undergoes a ferromagnetic to paramagnetic phase transition due to the pressure-induced polymerization. The polymeric phase remains stable after the pressure release. The depolymerization of the pressure-induced phase was observed at the temperature of 520 K. Below room temperature, the polymeric phase behaves as a simple Curie-type insulator with one unpaired electron spin per chemical formula. The TDAE+^+ donor-related unpaired electron spins, formerly ESR-silent, become active above the temperature of 320 K and the Curie-Weiss behavior is re-established.Comment: Submitted to Phys. Rev.

    The Fast Read-out System for the MAPMTs of COMPASS RICH-1

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    A fast readout system for the upgrade of the COMPASS RICH detector has been developed and successfully used for data taking in 2006 and 2007. The new readout system for the multi-anode PMTs in the central part of the photon detector of the RICH is based on the high-sensitivity MAD4 preamplifier-discriminator and the dead-time free F1-TDC chip characterized by high-resolution. The readout electronics has been designed taking into account the high photon flux in the central part of the detector and the requirement to run at high trigger rates of up to 100 kHz with negligible dead-time. The system is designed as a very compact setup and is mounted directly behind the multi-anode photomultipliers. The data are digitized on the frontend boards and transferred via optical links to the readout system. The read-out electronics system is described in detail together with its measured performances.Comment: Proceeding of RICH2007 Conference, Trieste, Oct. 2007. v2: minor change
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