12 research outputs found
中国自然保护地整合优化关键问题
自然保护地建设是国际公认的保护生物多样性、提供优质生态产品与服务、维系生态系统健康的最重要和最有效途径。自然保护地作为中国自然生态空间最精华和最重要的组成部分,是建设生态文明的核心载体,是美丽中国的重要象征,在维护国家生态安全中具有首要地位(唐小平等, 2019)。从1956年建立第一个自然保护地以来,中国自然保护地建设取得了巨大成就,保护体系逐步完善,建立了由自然保护区、风景名胜区、森林公园、地质公园、湿地公园等组成的数量众多、类型丰富、功能多样的自然保护地体系。截止到2019年底,中国已有各类自然保护地约1.18万处,大约覆盖了陆域国土面积的18%,占海域面积的4.6%(高吉喜等,2019),无论从数量上还是面积上均位居世界前列,为保护生物多样性、自然景观及自然遗迹,维护国家和区域生态安全等发挥了重要作用
北极黄河站生态环境考察与研究进展
北极黄河站位于北极斯瓦尔巴群岛新奥尔松地区,是生态系统对全球变化响应监测与研究的理想之地。我国自2004年建站以来,开展了系统的王湾海域生态断面和陆地植被样方的长期监测与研究,同时开展了环境污染和鸟类种群变迁等方面的考察与研究。结果表明:冰川退缩迹地上的物种更替明显,而范氏藓等可很好地反映该地区同时期的气温变化;从北极黄河站周边区域的海底沉积物、土壤、湖沉积物和冰川冰碛中分离获得了3个北极新属和21个北极新种,并发现了部分活性菌株;王湾海域微型浮游生物存在较高的生物多样性,其表层水存在潜在氮限制;微藻对温度有较好的适应性,具有通过自身调节来适应北极环境变化的能力;苔原植物对重金属具富集能力,大气传输是持久性有机污染物(POPs)污染来源的最主要途径;鸟类方面,在距今9 400年海鸟就已在该地区生活繁衍,种群数量存在明显波动并在距今7 650年左右达到最大。未来应坚持监测断面和样方的长期监测,进一步掌握生物群落的变化趋势;融合我国在该地区的大气、冰川、样方和海洋监测,开展大气-冰雪-陆地-海洋相互作用研究,聚焦科学问题并形成我国在该地区的研究特色
Template Induced Fabrication of Nitrogen Doped Carbon Sheets as Electrode Materials in Supercapacitors
兼具有优良的导电能力,高的比表面积和极佳的化学/机械稳定性,具有二维形貌的纳米碳材料近年来逐渐成为超级电容器电极材料的研究热点. 我们在此首次报道一种模板诱导方法以制备具有规整片状形貌的氮掺杂碳材料. 我们将作为硬模板的片状镁铝双金属氢氧化物与熔融的邻苯二胺混合后加入三氯化铁催化剂,进而通过加热使邻苯二胺聚合并碳化,随后刻蚀除去其中的氧化物成分即可以得到具有规整六边形片状氮掺杂碳材料. 通过改变碳化时的温度,可以有效的调节利用该方法所得到的氮掺杂碳片的形貌、结构、石墨化程度、氮含量以及比表面积. 更重要的是这些氮掺杂碳片在用作超级电容器电极材料时体现出优异的电化学性能,在0.5 A·g-1的电流密度下其比容量可以达到290.0 F·g-1的. 在1 A·g-1的电流密度下经过10000周循环测试后,其容量仍然可以达到初始值83%.Due to the good electrical conductivity, high specific surface area, and excellent chemical/mechanical stability, carbon nanomaterials with two-dimensional morphology have gradually become the hot topic of the research on supercapacitors. Herein, we report for the first time the fabrication of nitrogen doped carbon sheets (NCSs). In our approach, the sheet-like magnisum aluminum (MgAl) layered double hydroxide was used as the hard template, which was mixed with o-phenylene diamine and iron chloride. The following thermal treatment could render the polymerization and carbonization of o-phenylene diamine. The NCSs with ordered hexagonal architectures were formed by final etching process of the thermally treated mixture. The morphology, structure, graphitic degree, nitrogen content and surface area of the as-prepared NCSs could be adjusted by the temperatures of the thermal treatment. More importantly, the NCSs exhibited outstanding electrochemical performances as the electrode materials in supercapacitors. Among the NCSs, the sample obtained from 600 oC (NCS-600) achieved a capacity of 290.0 F·g-1 at a current density of 0.5 A·g-1. After 10,000 cycles at 1 A·g-1, the NCS-600 still retained 83% of its initial capacity, indicating high cycling stability.国家重点基础研究发展计划项目(973计划,2014CB239701)国家自然科学基金项目(21372155和21572132)资助作者联系地址:上海交通大学 化学化工学院,上海 200240Author's Address: School of Chemistry and chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China通讯作者E-mail:[email protected]
新疆扶桑绵粉蚧疫情的传入及扑灭概况[J]
本文概述了扶桑绵粉蚧近年在新疆传入扩散的情况。并根据扶桑绵粉蚧在新疆的发生及危害特点,总结了将其扑灭所采取的综合技术措施和经验,以供其他扶桑绵粉蚧发生地区参考
JUNO Sensitivity on Proton Decay Searches
The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is years, competitive with the current best limits on the proton lifetime in this channel