Results 21 to 30 of about 16,842 (206)

压力罐消解能谱法测定海洋生物中的210Po

open access: yesHe jishu
海产品中的210Po是人体内照射剂量的主要来源,准确测定海洋生物中210Po的比活度尤为重要。本文建立了海洋生物中210Po的压力罐消解-α能谱检测方法。该方法以209Po为产额示踪剂,海洋生物样品经压力罐消解处理后,在盐酸体系中用镍片自沉积方法分离210Po,使用α能谱仪进行测量。在本方法测定条件下,标准物质的测定结果与标准值一致,相对标准偏差为9.0%,全程放化回收率为92.9%~98.6%,方法检出限为0.18 Bq·kg-1。该方法操作简便高效、环境友好、回收率高且测定结果准确可靠 ...
林 静   +3 more
doaj   +1 more source

不受歡迎的生物多樣性:香港的外來植物物種 [PDF]

open access: yes, 2002
The flora of Hong Kong has been well-surveyed since the mid nineteenth century and has had a long history of alien plant invasions. To the present day, more than 2130 wild plant species have been recorded, including 238 species that are probably ...
Corlett, RT, Ng, SC
core  

Conservation Funding at the Local Level 地方层面的保护资金

open access: yesWildlife Letters, EarlyView.
Direct conservation fund transfer to local communities ensures the involvement of these communities in decision‐making and fund utilisation, which will ultimately lead to effective biodiversity conservation. A Cakchiquel family in the hamlet of Patzutzun, Guatemala, 1993. Credits: John Issac. Source: UNEP‐WCMC Internal Resources.
Jithu K Jose
wiley   +1 more source

Distribution Pattern of Taxonomic Diversity of Fish Community in Four Typical Mangrove Areas, China [PDF]

open access: yes, 2016
红树林区不仅能为许多海生和陆生生物提供栖息地和食物,还是许多鱼类的育幼场和产卵场,因此红树林区生物多样性成为当今生态学研究热点之一。过去对红树林区鱼类群落的研究多采用传统生物多样性指数,然而传统生物多样性指数在实际运用过程具有过多注重物种丰富度、未考虑物种在分类学上的差异等缺陷。分类多样性指数既考虑了群落中物种数量和均匀程度,也考虑了物种分类地位和生态学上的差异,更全面更有说服力。 为全面了解中国红树林区鱼类物种多样性分布格局,本研究选取福建漳江口、广西茅尾海、广西山口、海南东寨港四个典型的红树林区 ...
陈杰
core  

Changes of Potential Suitable Areas for Lynx Under Climate Change in Mohe Area, Daxing'anling Mountains, China 气候变化下中国大兴安岭漠河地区猞猁潜在适宜区的变化

open access: yesWildlife Letters, EarlyView.
Climate change drives shifts in suitable habitats for Eurasian lynx and its prey (hare, roe deer) in Mohe, Daxing'anling Mountains. Under RCP scenarios, moderate warming (RCP4.5) promotes substantial habitat expansion, while high‐emission conditions (RCP8.5) lead to strong expansion in the 2050s but slower gains and partial contraction by the 2070s ...
Binglian Liu   +5 more
wiley   +1 more source

Floristic analysis of the seed plants from Yandang Mountain of Yueqing, Zhejiang(浙江乐清雁荡山种子植物区系分析)

open access: yesZhejiang Daxue xuebao. Lixue ban, 2018
在文献查阅、野外调查和标本鉴定的基础上,对浙江乐清雁荡山种子植物区系特征进行了统计分析,得到:(1)区域内共有野生种子植物732种(含种下类群),隶属147科、433属;科、属水平显示出多样性,含1个种的科和属分别占总科数和总属数的41.5%和67.9%. (2)科的分布区类型中,热带成分有64科,占总科数的42.9%,温带成分共36科,占24.6%;属的分布区类型中,热带成分和温带地理成分分别占总属数的49.1% 和50.9%,泛热带分布及其变型所占比例最大,为24.1%.
CHENWeijie(陈伟杰)   +3 more
doaj   +1 more source

Cost-effective Solutions of Nitrogen Reduction in Enclosed Bay: Case Study of Sansha Bay, Fujian Province [PDF]

open access: yes, 2016
由于污染物过度排放导致环境质量下降和生境退化是目前全球很多海湾面临的重要挑战,而总氮、总磷等营养盐是造成海湾水体污染和生境退化的主要原因之一。营养盐削减,特别是通过海岸带湿地修复进行营养盐削减不仅可以缓解水体富营养化改善水质,还可以达到改善海湾生境的质量的目的。由于来源的多样性和复杂性,营养盐削减需要大量的成本。在需要解决的环境问题日益增多而预算有限的约束下,研究达到预定的环境目标、成本最低的营养盐削减方案是当务之急。不同地区、不同营养盐削减措施的成本不同,同时,不同地区 ...
徐瑞琦
core  

Movement and Space Use Patterns of the Beale's Eyed Turtle (Sacalia bealei) Suggest Sensitivity to Environmental Changes and Poaching 比氏眼斑龟 (Sacalia bealei) 的活动与空间利用模式揭示其对环境变化及盗猎的敏感性

open access: yesWildlife Letters, EarlyView.
Using radiotelemetry, we found that the movement and home range of the endangered Sacalia bealei varied significantly across reproductive classes and seasons, with males exhibiting greater movement than females during wet and mating seasons. The species exhibits strong aquatic dependence, favoring deep pools interspaced among riffle‐pool sequences ...
Wing Sing Chan   +3 more
wiley   +1 more source

安氏新银鱼(Neosalanx anderssoni)性别特异性位点筛选及性别鉴定方法开发

open access: yesHaiyang yu huzhao
安氏新银鱼是我国重要的小型经济鱼类物种,具有较高的经济价值。但目前缺乏一种快速、经济有效的性别鉴定方法,极大地阻碍了其性别决定分子机制、性染色体演化历程的研究和水产育种与养殖技术方面的生产实践。本研究通过比较安氏新银鱼雌性与雄性的全基因组重测序数据,发现雌雄之间存在一个显著差异的基因组区域(chr02: 2 798 574~5 434 239 bp)。基于测序深度差异分析筛选得到3个雌性特异性片段,长度分别为10 bp、167 bp和53 bp。在长为167 bp的雌性特异性位点附近设计引物 ...
王 心悦   +4 more
doaj   +1 more source

Research on Optimization of Fe Clusters Structure Based on Structural Clustering Niche Differential Evolution Algorithm [PDF]

open access: yes, 2016
团簇被称之为“物质第五态”。它是材料科学的新起点,在许多领域都有着广泛的应用。团簇的稳态结构对其独特的物理和化学等性质起到了至关重要的作用,因而受到许多学者的广泛关注。由于团簇的大小在几埃到几百埃之间,尺寸非常小,用实验设备很难合成和直接观测。因此用理论研究的方法来探究团簇的稳态结构显得十分重要。但是寻找团簇的稳态结构十分困难,除了基态结构之外,还存在成千上万的亚稳态结构。目前团簇优化问题已被学者证明为NP难问题,因此用传统的优化方法难以获得最优解,于是使得基于进化算法的全局优化方法得到了广泛应用 ...
郑骥文
core  

Home - About - Disclaimer - Privacy