14 research outputs found

    ADVANCES IN CHROMASOME RESEARCH IN MARINE ZOOPLANKTON IN CHINA

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    国家自然科学基础研究重大项目G1999043708

    Spring Characteristics of Benthic Dinoflagellates in the East Coastal Beach of Xiamen Island

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    20 0 0年春季 ,对厦门岛东海岸黄厝沙滩底栖甲藻的种类组成和时空分布进行了调查 .发现初春甲藻数量少 ,而春末夏初数量显著增多 ,由春初的 0~ 2 0个 / 10 0 0 g湿砂增加到春末夏初的几千个 / 10 g湿砂 ,相差 3个数量级以上 ;Amphidinium britanicum和 Adenoides eludens为春季优势种 ;Gyrodinium viridescense和 Peridinium quinquecorne在 5月份数量明显增多 ,与温度升高以及底栖藻类各类群总量增加有密切关系 ;底栖甲藻的总细胞密度和主要优势种的细胞密度呈现由高潮带向中、低潮带增加的趋势 .还探讨了超声波处理在野外底栖甲藻定量研究中的重要意义In this study, the species compositions and the temporal and spatial distribution of sand dwelling dinoflagellates in the intertidal zone of Huangcuo Beach, Xiamen Island, were investigated from March to May. It was revealed that the total cell density increased from early March to May, with a variation of 3 order of magnitudes in cell richness; Amphidinium britannicum and Adenoides eludens were two dominant species in the spring, however Gyrodinium viridescence and Peridinium quinquecorne might be abundant in the early summer; the cell density of dominant species inclined from the high tide zone to middle and low tide zone. Finally, the importance of sonification treatment in precise cell enumeration of nature samples was discussed. This is the first report of specialized benthic dinoflagellate study in China.厦门大学校级自选课题资助项目 !( Y0 70 0 3

    PEMFC不锈钢双极板离子镀CrNX薄膜表面改性

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    用电弧离子镀膜技术通过改变N2流量的方法,在质子交换膜燃料电池(PEMFC)中用不锈钢双极板表面沉积一系列不同N含量的CrNx改性薄膜,对薄膜的成分、结构与接触电阻、耐蚀性能进行了测试。结果表明,沉积CrNx薄膜能够明显改善双极板的表面性能,并且其性能随着薄膜中N含量的变化而变化。与原始不锈钢相比,接触电阻降低1个数量级,耐腐蚀性能提高2个数量级。其中N含量为46.2%时,接触电阻降低到了11.8mΩ·cm^2(0.8MPa夹紧力);N含量为50.5%时,极化电流降低到10^-7A/cm^2(电极电位为0.6V)。分析表明,双极板处理后性能的改善与电弧离子镀薄膜的致密度较高,以及薄膜的成分、结构随薄膜中N含量的变化有关

    中国被子植物濒危等级的评估

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    本文基于文献和标本信息收集以及专家提供的数据,运用IUCN濒危物种红色名录方法首次对中国范围内所有已知被子植物进行灭绝风险评估。结果显示,在评估的30,068种被子植物中,灭绝等级(含灭绝、野外灭绝、地区灭绝)共计40种;受威胁等级(极危、濒危、易危)3,363种,受威胁比例为11.18%。从空间分布看,我国受威胁被子植物主要集中分布在西南地区以及台湾、海南等岛屿,且主要分布在中低海拔地区。对受威胁物种的分析结果表明,包括原生植被破坏在内的生境丧失及破碎化是我国被子植物濒危的首要因子,涉及约84.1%的受威胁物种;过度采挖和物种内在系统问题位列致危因子的第二、三位,分别涉及38%和14%的物种。其他的致危因子包括外来入侵种在内的种间竞争、环境污染、自然灾害和全球气候变化等。一个物种的致危因子往往是多方面的。本次评估与2004年红色名录相比,生境变化、实施保护措施及分类学新修订使一些物种的濒危等级发生了变化,这也印证了红色名录是一个动态的系统,需要根据最新信息进行更新,以便为生物多样性保护提供实时准确的基础数据

    中国高等植物受威胁物种名录

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    2008年,环境保护部和中国科学院联合启动了《中国生物多样性红色名录——高等植物卷》的编制工作。通过这项工作,我们依据IUCN濒危物种红色名录标准对中国野生高等植物的濒危状况进行了全面评估,编制了中国高等植物红色名录。2013年9月,该名录以环境保护部、中国科学院第54号公告形式发布,即《中国生物多样性红色名录—

    Measurement of integrated luminosity of data collected at 3.773 GeV by BESIII from 2021 to 2024*

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    Determination of the number of ψ(3686) events taken at BESIII

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    The number of ψ(3686) events collected by the BESIII detector during the 2021 run period is determined to be (2259.3±11.1)×106 by counting inclusive ψ(3686) hadronic events. The uncertainty is systematic and the statistical uncertainty is negligible. Meanwhile, the numbers of ψ(3686) events collected during the 2009 and 2012 run periods are updated to be (107.7±0.6)×106 and (345.4±2.6)×106, respectively. Both numbers are consistent with the previous measurements within one standard deviation. The total number of ψ(3686) events in the three data samples is (2712.4±14.3)×10^

    Amplitude analysis of the decays D0π+ππ+πD^0\rightarrow\pi^+\pi^-\pi^+\pi^- and D0π+ππ0π0D^0\rightarrow\pi^+\pi^-\pi^0\pi0

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    Prediction of Energy Resolution in the JUNO Experiment

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    International audienceThis paper presents the energy resolution study in the JUNO experiment, incorporating the latest knowledge acquired during the detector construction phase. The determination of neutrino mass ordering in JUNO requires an exceptional energy resolution better than 3% at 1 MeV. To achieve this ambitious goal, significant efforts have been undertaken in the design and production of the key components of the JUNO detector. Various factors affecting the detection of inverse beta decay signals have an impact on the energy resolution, extending beyond the statistical fluctuations of the detected number of photons, such as the properties of liquid scintillator, performance of photomultiplier tubes, and the energy reconstruction algorithm. To account for these effects, a full JUNO simulation and reconstruction approach is employed. This enables the modeling of all relevant effects and the evaluation of associated inputs to accurately estimate the energy resolution. The study reveals an energy resolution of 2.95% at 1 MeV. Furthermore, the study assesses the contribution of major effects to the overall energy resolution budget. This analysis serves as a reference for interpreting future measurements of energy resolution during JUNO data taking. Moreover, it provides a guideline in comprehending the energy resolution characteristics of liquid scintillator-based detectors
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