本研究首次通过CiteSpace分析水环境中汞的研究现状,总结了研究热点和前沿。从中国知网、万方、维普3大中文数据库和Web of Science Core Collection(WoSCC)检索了2008—2023年与水环境中汞有关的研究,检索到相关文献697篇。使用CiteSp...本研究首次通过CiteSpace分析水环境中汞的研究现状,总结了研究热点和前沿。从中国知网、万方、维普3大中文数据库和Web of Science Core Collection(WoSCC)检索了2008—2023年与水环境中汞有关的研究,检索到相关文献697篇。使用CiteSpace生成了作者/国家/机构之间的合作网络图谱,获得了关键词共现以及聚类图谱。结果表明:1)论文最高产者所发表的文章为8篇,截至目前尚未形成核心作者团队;2)中国和中国科学院大学是该领域的领先国家和机构,分别发表了450篇和21篇论文;3)研究热点集中在汞离子、甲基汞、沉积物、原子荧光法、吸附以及水生生物。基于CiteSpace的研究结果,发现了国家、机构和作者之间的密切合作。目前主要研究趋势为水环境中汞的检测方法和去除技术,因此,未来应更加重视高性能纳米材料的制备和汞离子监测网络的完善,建立更加完善的汞离子监测预警方法。展开更多
The effects of nano-CaO contents on the microstructure,mechanical properties and corrosion resistance of lean Mg-1Zn alloy were investigated.The results showed that the addition of nano-CaO significantly refined the g...The effects of nano-CaO contents on the microstructure,mechanical properties and corrosion resistance of lean Mg-1Zn alloy were investigated.The results showed that the addition of nano-CaO significantly refined the grain size and improved mechanical properties of the Mg-1Zn alloy.At the same time,CaO reacted with molten Mg in situ to form nano-MgO,whose corrosion product in SBF solution was the same with the degradation product of Mg matrix,resulting in the enhanced compactness of the Mg(OH)_(2) layer and reduced corrosion rate of matrix.The Mg-1Zn alloy had lower corrosion resistance due to excessively large grain size and shedding of corrosion products.The composite with 0.5 wt.%CaO had the best corrosion resistance with a weight loss of 9.875 mg·y^(-1)·mm^(-2)due to the small number of Ca_(2)Mg_(6)Zn_(3) phase and suitable grain size.While for composites with high content of CaO(0.7 wt.%and 1.0 wt.%),they had lower corrosion resistance due to the coexistence of large number of Ca_(2)Mg_(6)Zn_(3) and Mg_(2)Ca at grain boundaries,especially for 1.0 wt.%CaO composite,resulting from the strong micro-galvanic corrosion.展开更多
【目的】全面揭示哀牢山国家级自然保护区蚂蚁物种的多样性。【方法】采用样地调查法对该保护区的蚂蚁物种分布格局进行调查。【结果】8个垂直带的58块样地共采集蚂蚁10亚科61属209种。水平分布上,西坡的蚂蚁物种数高于东坡(171 vs 145)...【目的】全面揭示哀牢山国家级自然保护区蚂蚁物种的多样性。【方法】采用样地调查法对该保护区的蚂蚁物种分布格局进行调查。【结果】8个垂直带的58块样地共采集蚂蚁10亚科61属209种。水平分布上,西坡的蚂蚁物种数高于东坡(171 vs 145),西坡特有种64种,东坡特有种38种,东、西坡共有种107种;垂直分布上,东、西坡的蚂蚁物种数均与海拔负相关(西坡R^(2)=0.65,东坡R^(2)=0.63);10类不同生境中,中低海拔的针阔混交林和季风常绿阔叶林中栖息的蚂蚁物种较为丰富(分别为127和104种),高海拔的苔藓矮林中蚂蚁物种最贫乏(3种);觅食和筑巢分析中,土壤为蚂蚁最喜欢的觅食和筑巢场所,其次为地表,最后为植物上。【结论】哀牢山国家级自然保护区资源丰富,植被保护整体良好,孕育着丰富的蚂蚁物种。低海拔的人为干扰对蚂蚁物种有不利影响。多数(超过70%)蚂蚁物种的水平分布、垂直分布和栖息生境都十分有限,生态位极其狭窄,具有极高的保护价值。展开更多
文摘本研究首次通过CiteSpace分析水环境中汞的研究现状,总结了研究热点和前沿。从中国知网、万方、维普3大中文数据库和Web of Science Core Collection(WoSCC)检索了2008—2023年与水环境中汞有关的研究,检索到相关文献697篇。使用CiteSpace生成了作者/国家/机构之间的合作网络图谱,获得了关键词共现以及聚类图谱。结果表明:1)论文最高产者所发表的文章为8篇,截至目前尚未形成核心作者团队;2)中国和中国科学院大学是该领域的领先国家和机构,分别发表了450篇和21篇论文;3)研究热点集中在汞离子、甲基汞、沉积物、原子荧光法、吸附以及水生生物。基于CiteSpace的研究结果,发现了国家、机构和作者之间的密切合作。目前主要研究趋势为水环境中汞的检测方法和去除技术,因此,未来应更加重视高性能纳米材料的制备和汞离子监测网络的完善,建立更加完善的汞离子监测预警方法。
基金the financial support for this work from the National Natural Science Foundation of China(Nos.52171241,52201301 and 51871166)。
文摘The effects of nano-CaO contents on the microstructure,mechanical properties and corrosion resistance of lean Mg-1Zn alloy were investigated.The results showed that the addition of nano-CaO significantly refined the grain size and improved mechanical properties of the Mg-1Zn alloy.At the same time,CaO reacted with molten Mg in situ to form nano-MgO,whose corrosion product in SBF solution was the same with the degradation product of Mg matrix,resulting in the enhanced compactness of the Mg(OH)_(2) layer and reduced corrosion rate of matrix.The Mg-1Zn alloy had lower corrosion resistance due to excessively large grain size and shedding of corrosion products.The composite with 0.5 wt.%CaO had the best corrosion resistance with a weight loss of 9.875 mg·y^(-1)·mm^(-2)due to the small number of Ca_(2)Mg_(6)Zn_(3) phase and suitable grain size.While for composites with high content of CaO(0.7 wt.%and 1.0 wt.%),they had lower corrosion resistance due to the coexistence of large number of Ca_(2)Mg_(6)Zn_(3) and Mg_(2)Ca at grain boundaries,especially for 1.0 wt.%CaO composite,resulting from the strong micro-galvanic corrosion.
文摘【目的】全面揭示哀牢山国家级自然保护区蚂蚁物种的多样性。【方法】采用样地调查法对该保护区的蚂蚁物种分布格局进行调查。【结果】8个垂直带的58块样地共采集蚂蚁10亚科61属209种。水平分布上,西坡的蚂蚁物种数高于东坡(171 vs 145),西坡特有种64种,东坡特有种38种,东、西坡共有种107种;垂直分布上,东、西坡的蚂蚁物种数均与海拔负相关(西坡R^(2)=0.65,东坡R^(2)=0.63);10类不同生境中,中低海拔的针阔混交林和季风常绿阔叶林中栖息的蚂蚁物种较为丰富(分别为127和104种),高海拔的苔藓矮林中蚂蚁物种最贫乏(3种);觅食和筑巢分析中,土壤为蚂蚁最喜欢的觅食和筑巢场所,其次为地表,最后为植物上。【结论】哀牢山国家级自然保护区资源丰富,植被保护整体良好,孕育着丰富的蚂蚁物种。低海拔的人为干扰对蚂蚁物种有不利影响。多数(超过70%)蚂蚁物种的水平分布、垂直分布和栖息生境都十分有限,生态位极其狭窄,具有极高的保护价值。
