84 research outputs found

    Measurement of tensor analyzing powers in deuteron photodisintegration

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    New accurate measurement of tensor analyzing powers T20, T21 and T22 in deuteron photodisintegration has been performed. Wide-aperture non-magnetic detectors allowed to cover broad kinematic ranges in a single setup: photon energy = 25 to 600 MeV, proton emission angle in CM = 24 to 48 deg. and 70 to 102 deg. New data provide a significant improvement of a few existing measurements. The angular dependency of the tensor asymmetries in deuteron photodisintegration is extracted for the first time.Comment: 4 pages, 5 figures, submitted to Phys. Rev. Let

    Electrosynthesis of stable betulin-derived nitrile oxides and their application in synthesis of cytostatic lupane-type triterpenoid-isoxazole conjugates

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    Novel lupane-type triterpenoid-isoxazole conjugates were designed by direct placing of isoxazole linker at C(17) of triterpenoid. The suggested synthetic sequence demonstrates successful combination of electro-organic synthesis and conventional approaches. TEMPO-mediated electrooxidation of betulin to betulinal was developed and optimized at boron-doped diamond anodes with potassium acetate as inexpensive supporting electrolyte. Betulinal-derived oxime was further selectively electro-oxidized at a graphite anode to nitrile oxide, which proved to be stable and isolable species. The same reaction sequence was performed with 3β-lupane-3,28-diol. Nitrile oxides were characterized by 15N NMR and X-ray crystallography. The isolable nitrile oxides allowed creation of isoxazole library by 1,3-dipolar cycloaddition reactions with various alkynes. Some of the title conjugates exhibit cytostatic properties against breast cancer cell line MCF7, glioblastoma multiform cell line U-87 MG and lung carcinoma cell line A549 with growth inhibition (GI50) concentrations up to 11 μm, while being harmless to immortalized human fibroblasts hTERT (GI50 >100 μm)

    Increase of precision of casting blocks by applying acoustical oscillations in gas-impulsive moulding

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    The present article shows the results of the theoretical and empirical research of the study of the impact made by acoustical oscillations on the working process of a gas-impulsive moulding device with the purpose of increasing the quality of the casting blocks’ seal and decreasing the roughness of the surface of a casting block. It has been shown that acoustical oscillations intensify the working process of the gas-impulsive moulding device. With the increase of frequency and power of oscillations the hardness of a casting block first sharply rises, but then gradually decreases. It has been found out that oscillations may help to adjust the precision of a casting block due to high sensitivity of a gas-impulsive process to the frequency of oscillations. The use of acoustical oscillations broadens technological opportunities of the moulding device

    The significance of retained austenite in the high strength and plasticity of medium carbon Q&P steel

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    The Fe-0.44%C-1.8%Si-1.3%Mn-0.82%Cr-0.28%Mo steel treated by the quenching-partitioning partitioning process showed a product of strength and elongation of 30 GPa % with yield stress of 1350 MPa. Such a combination of high ultimate tensile strength and good ductility is attributed to a high portion of retained austenite (≥20%) transforming to martensite under tension. The high yield stress is provided by carbon supersaturation of austenite and a high dislocation density in this phas

    Measurement of J/ψγηcJ/\psi\to\gamma\eta_{\rm c} decay rate and ηc\eta_{\rm c} parameters at KEDR

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    Using the inclusive photon spectrum based on a data sample collected at the J/ψJ/\psi peak with the KEDR detector at the VEPP-4M e+ee^+e^- collider, we measured the rate of the radiative decay J/ψγηcJ/\psi\to\gamma\eta_{\rm c} as well as ηc\eta_{\rm c} mass and width. Taking into account an asymmetric photon lineshape we obtained Γγηc0=2.98±0.180.33+0.15\Gamma^0_{\gamma\eta_{\rm c}}=2.98\pm0.18 \phantom{|}^{+0.15}_{-0.33} keV, Mηc=2983.5±1.43.6+1.6M_{\eta_{\rm c}} = 2983.5 \pm 1.4 \phantom{|}^{+1.6}_{-3.6} MeV/c2c^2, Γηc=27.2±3.12.6+5.4\Gamma_{\eta_{\rm c}} = 27.2 \pm 3.1 \phantom{|}^{+5.4}_{-2.6} MeV.Comment: 6 pages, 3 figure

    Precise measurement of RudsR_{\text{uds}} and RR between 1.84 and 3.72 GeV at the KEDR detector

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    The present work continues a series of the KEDR measurements of the RR value that started in 2010 at the VEPP-4M e+ee^+e^- collider. By combining new data with our previous results in this energy range we measured the values of RudsR_{\text{uds}} and RR at nine center-of-mass energies between 3.08 and 3.72 GeV. The total accuracy is about or better than 2.6%2.6\% at most of energy points with a systematic uncertainty of about 1.9%1.9\%. Together with the previous precise RR measurement at KEDR in the energy range 1.84-3.05 GeV, it constitutes the most detailed high-precision RR measurement near the charmonium production threshold.Comment: arXiv admin note: text overlap with arXiv:1610.02827 and substantial text overlap with arXiv:1510.0266

    Measurement of J/psi to eta_c gamma at KEDR

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    We present a study of the inclusive photon spectra from 5.9 million J/psi decays collected with the KEDR detector at the VEPP-4M e+e- collider. We measure the branching fraction of radiative decay J/psi to eta_c gamma, eta_c width and mass. Our preliminary results are: M(eta_c) = 2979.4+-1.5+-1.9 MeV, G(eta_c) = 27.8+-5.1+-3.3 MeV, B(J/psi to eta_c gamma) = (2.34+-0.15+-0.40)%.Comment: To be published in Proceedings of the PhiPsi09, Oct. 13-16, 2009, Beijing, Chin

    Measurement of B(J/psi->eta_c gamma) at KEDR

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    We present a study of the inclusive photon spectrum from 6.3 million J/psi decays collected with the KEDR detector at the VEPP-4M e+e- collider. We measure the branching fraction of the radiative decay J/psi -> eta_c gamma, eta_c width and mass. Taking into account an asymmetric photon line shape we obtain: M(eta_c) = (2978.1 +- 1.4 +- 2.0) MeV/c^2, Gamma(eta_c) = (43.5 +- 5.4 +- 15.8) MeV, B(J/psi->eta_c gamma) = (2.59 +- 0.16 +- 0.31)%$.Comment: 6 pages, 1 figure. To be published in the proceedings of the 4th International Workshop on Charm Physics (Charm2010), October 21-24, 2010, IHEP, Beijin
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