274 research outputs found

    Study on Ultrasonic Degradation of Pentachlorophenol Solution

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    Pentachlorophenol (PCP) ion was degraded by ultrasound at 25 C. Four aspects that could affect the degradation of PCP were investigated, i.e. initial pH of solution, initial concentration of pentachlorophenol ion, different sound intensity with catalyst and different frequencies of ultrasound. Results showed that PCP ion could be ultrasonic degraded totally after 3 hour treatment if CCl4, which can provide free radical, was added in solution. The mechanism of ultrasonic degradation was considered as free radical oxidation by adding n-butyl alcohol as free radical scavenger

    Study on Ultrasonic Degradation of Pentachlorophenol Solution

    Get PDF
    Pentachlorophenol (PCP) ion was degraded by ultrasound at 25 C. Four aspects that could affect the degradation of PCP were investigated, i.e. initial pH of solution, initial concentration of pentachlorophenol ion, different sound intensity with catalyst and different frequencies of ultrasound. Results showed that PCP ion could be ultrasonic degraded totally after 3 hour treatment if CCl4, which can provide free radical, was added in solution. The mechanism of ultrasonic degradation was considered as free radical oxidation by adding n-butyl alcohol as free radical scavenger

    Respuestas del δ13C foliar y características foliares a la precipitación y temperatura en un ecosistema árido del noroeste de China

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    El δ13C foliar es ampliamente usado para explicar estrategias relacionadas con la disponibilidad de recursos en diferentes ambientes. Sin embargo, la respuesta conjunta del δ13C foliar a la precipitación y temperatura así como la relación entre el δ13C foliar y las características foliares no están claras. El δ13C foliar y su relación con las características foliares [tamaño de hoja (LS), longitud foliar (LL), ancho foliar (LW), relación entre la longitud y el ancho foliar (L:W), área foliar específica (SLA) y concentración de N foliar (en una base de peso seco) (Nmass)] fueron investigadas en la especie de arbusto dominante Nitraria tangutorum Bobr en la región árida (Dengkou y Minqin) del noroeste de China. El estudio se efectuó bajo condiciones de varias cantidades de precipitación simuladas (PGS) y temperaturas ambientales (TGS) en las estaciones de crecimiento de 2008, 2009 y 2010. Los resultados mostraron que LS, LW, LL, SLA y Nmass se incrementaron significativamente cuando las cantidades de PGS se incrementaron, pero hubo tendencias de reducción en dichas características cuando las TGS aumentaron. Sin embargo, la mayoría de las relaciones negativas entre las características foliares y las TGS no fueron obvias en Minqin. En ambos sitios, L:W se incrementó cuando las PGS y TGS aumentaron. Hubo un cambio en la relación negativa entre el δ13C foliar-PGS a través de Minqin y Dengkou, lo cual condujo a la falta de efectos de la precipitación en el δ13C foliar a través de ambos sitios, y mayor δ13C foliar a menor precipitación en Minqin. A través de Minqin y Dengkou, PGS solo pudo explicar un 14% de la variación en el δ13C foliar. La combinación de PGS y TGS pudo explicar un 64% de la variación en el δ13C foliar. Las características foliares (LW y L:W) mejoraron aún más la estimación del δ13C foliar. Las combinaciones de PGS, TGS, LW y L:W pudieron explicar un 84% de la variación en el δ13C foliar. Nuestro estudio demostró la importancia de las características foliares en explorar las respuestas del δ13C foliar a cambios globales en ecosistemas áridos.Leaf δ13C is widely used to explain plant strategies related to resource availability in different environments. To understand the coupled response of leaf δ13C to precipitation, temperature and the relationship between leaf δ13C and leaf traits in arid ecosystems, the leaf δ13C and leaf traits (leaf size (LS), leaf length (LL), leaf width (LW), leaf length to width ratio (L:W), specific leaf area (SLA) and mass-based leaf nitrogen concentration (Nmass)) of Nitraria tangutorum Bobr. under simulated increasing precipitation (PGS) and ambient temperature (TGS) in plant growing season from 2008 to 2010 and the relationships between leaf δ13C and leaf traits were investigated in the arid region (Dengkou and Minqin) of northwestern China. Our results showed that LS, LW, LL, SLA and Nmass significantly increased with increasing PGS, but had downward tendencies with increasing TGS although the majority of the negative relationships between leaf traits and TGS were not obvious in Minqin. At the two study sites, L:W increased simultaneously with increasing PGS and TGS. There was a shift in the negative leaf δ13C-PGS relationship across Minqin and Dengkou, which conduce to the lacking effect of precipitation on leaf δ13C across the two sites and higher leaf δ13C in lower precipitation fields in Minqin. Across Minqin and Dengkou, PGS could only explain 14% of the variation in leaf δ13C. The combinations of PGS and TGS could explain 64% of the variation in leaf δ13C. Leaf traits (LW and L:W) could be used to further improve the estimation of leaf δ13C. The combinations of PGS, TGS, LW and L:W could explain 84 % of the variation in leaf δ13C. Our study demonstrated the importance of leaf traits in exploring the responses of leaf δ13C to global changes in arid ecosystems.Fil: Xin, Z.M.. Chinese Academy of Forestry. Institute of Desertification Studies; China. Chinese Academy of Forestry. Experimental Center of Desert Forestry; ChinaFil: Liu, M.H.. Chinese Academy of Forestry. Experimental Center of Desert Forestry; ChinaFil: Lu, Q.. Chinese Academy of Forestry. Institute of Desertification Studies; China. State Forestry Administration. Kumtag Desert Ecosystem Research Station; ChinaFil: Busso, Carlos Alberto. Universidad Nacional del Sur. Departamento de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. State Forestry Administration. Kumtag Desert Ecosystem Research Station; ChinaFil: Zhu, Y.J.. State Forestry Administration. Kumtag Desert Ecosystem Research Station; China. Chinese Academy of Forestry. Institute of Desertification Studies; ChinaFil: Li, Z.. Chinese Academy of Forestry. Experimental Center of Desert Forestry; ChinaFil: Huang, Y.R.. Chinese Academy of Forestry. Experimental Center of Desert Forestry; ChinaFil: Li, X.L.. Chinese Academy of Forestry. Experimental Center of Desert Forestry; ChinaFil: Luo, F.M.. Chinese Academy of Forestry. Experimental Center of Desert Forestry; ChinaFil: Bao, F.. Chinese Academy of Forestry. Institute of Desertification Studies; ChinaFil: Qian, J.Q.. Henan Agricultural University. College of Forestry; ChinaFil: Li, Y.H.. Chinese Academy of Forestry. Institute of Desertification Studies; China. State Forestry Administration. Kumtag Desert Ecosystem Research Station; Chin

    The open-charm radiative and pionic decays of molecular charmonium Y(4274)

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    In this work, we investigate the decay widths and the line shapes of the open-charm radiative and pionic decays of Y(4274) with the DsDˉs0(2317)D_s\bar{D}_{s0}(2317) molecular charmonium assignment. Our calculation indicates that the decay widths of Y(4274)Ds+DsγY(4274)\to D^{+}_{s}D^{*-}_{s}\gamma and Y(4274)Ds+Dsπ0Y(4274)\to D^+_{s}D^-_{s}\pi^0 can reach up to 0.05 keV and 0.75 keV, respectively. In addition, the result of the line shape of the photon spectrum of Y(4274)Ds+DsγY(4274)\to D_s^+ {D}_s^{*-} \gamma shows that there exists a very sharp peak near the large end point of photon energy. The line shape of the pion spectrum of Y(4274)Ds+Dsπ0Y(4274)\to D_s^+ {D}_s^{*-} \pi^0 is similar to that of the pion spectrum of Y(4274)Ds+DsγY(4274)\to D_s^+ {D}_s^{*-} \gamma, where we also find a very sharp peak near the large end point of pion energy. According to our calculation, we suggest further experiments to carry out the search for the open-charm radiative and pionic decays of Y(4274).Comment: 7 pages, 6 figures, 1 table. Published versio

    omega-nucleus bound states in the Walecka model

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    Using the Walecka model, we investigate theoretically whether an omega meson is bound to finite nuclei. We study several nuclei from ^{6}He to ^{208}Pb, and compare the results with those in the quark-meson coupling (QMC) model. Our calculation shows that deeper omega-nucleus bound states are predicted in the Walecka model than in QMC. One can expect to detect such bound states in the proposed experiment involving the (d,^3He) reaction at GSI.Comment: 11 pages, including 2 ps files and 2 table

    Measurements of the Mass and Full-Width of the ηc\eta_c Meson

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    In a sample of 58 million J/ψJ/\psi events collected with the BES II detector, the process J/ψγηc\psi\to\gamma\eta_c is observed in five different decay channels: γK+Kπ+π\gamma K^+K^-\pi^+\pi^-, γπ+ππ+π\gamma\pi^+\pi^-\pi^+\pi^-, γK±KS0π\gamma K^\pm K^0_S \pi^\mp (with KS0π+πK^0_S\to\pi^+\pi^-), γϕϕ\gamma \phi\phi (with ϕK+K\phi\to K^+K^-) and γppˉ\gamma p\bar{p}. From a combined fit of all five channels, we determine the mass and full-width of ηc\eta_c to be mηc=2977.5±1.0(stat.)±1.2(syst.)m_{\eta_c}=2977.5\pm1.0 ({stat.})\pm1.2 ({syst.}) MeV/c2c^2 and Γηc=17.0±3.7(stat.)±7.4(syst.)\Gamma_{\eta_c} = 17.0\pm3.7 ({stat.})\pm7.4 ({syst.}) MeV/c2c^2.Comment: 9 pages, 2 figures and 4 table. Submitted to Phys. Lett.

    Study of J/psi decays to Lambda Lambdabar and Sigma0 Sigma0bar

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    The branching ratios and Angular distributions for J/psi decays to Lambda Lambdabar and Sigma0 Sigma0bar are measured using BESII 58 million J/psi.Comment: 11 pages, 5 figure

    Measurements of J/psi Decays into 2(pi+pi-)eta and 3(pi+pi-)eta

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    Based on a sample of 5.8X 10^7 J/psi events taken with the BESII detector, the branching fractions of J/psi--> 2(pi+pi-)eta and J/psi-->3(pi+pi-)eta are measured for the first time to be (2.26+-0.08+-0.27)X10^{-3} and (7.24+-0.96+-1.11)X10^{-4}, respectively.Comment: 11 pages, 6 figure

    BESII Detector Simulation

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    A Monte Carlo program based on Geant3 has been developed for BESII detector simulation. The organization of the program is outlined, and the digitization procedure for simulating the response of various sub-detectors is described. Comparisons with data show that the performance of the program is generally satisfactory.Comment: 17 pages, 14 figures, uses elsart.cls, to be submitted to NIM
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