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Analysis and Assessment on the Heavy Metals in a Severely Degraded Subtropical Red Soil Region
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作者 Fang Wang Yun Zhou +5 位作者 Xiangping Fu yuxiao zhao Yiyao Wen Xintao Cui Shunbao Lu Yanjie Zhang 《American Journal of Plant Sciences》 CAS 2024年第2期110-121,共12页
5 different forests of Pinus massoniana, Schima superba, Liquidambar formosana, P. massoniana × S. superba, P. massoniana × L. formosana as the research object were set up to study the Cr, Cu and Zn content ... 5 different forests of Pinus massoniana, Schima superba, Liquidambar formosana, P. massoniana × S. superba, P. massoniana × L. formosana as the research object were set up to study the Cr, Cu and Zn content of degraded red soil region in subtropics. The soil heavy metal pollution degree was evaluated by national environmental quality standard (II class). The results showed that three soil metals of P. massoniana × S. superba were the highest, and the soil metals enrichment ability was strong. The order of single factor pollution index of metal elements was Cu (1.38) > Cr (0.81) > Zn (0.42), and moderately pollution, pollution warning and no pollution, respectively. There was no significant correlation between three soil heavy metals and soil total carbon (TC), total nitrogen (TN) and total phosphorus (TP). These results suggested that the accumulation of heavy metal elements was not derived from the parent material of soil. There was a significant positive correlation between the three metal elements which indicated that the sources of the three elements were similar. The structural equation model showed that the direct and indirect effects among the influencing factors ultimately affected the activity of heavy metals by cascade effects. 展开更多
关键词 Subtropical Forest Type Degraded Red Soil Heavy Metals Pollution Evaluation
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微/纳米多孔低介电聚酰亚胺薄膜的研究进展 被引量:1
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作者 赵宇霄 冯鑫 +4 位作者 冯晨曦 王玉辉 程金雪 于晓亮 郭敏杰 《高分子材料科学与工程》 EI CAS CSCD 北大核心 2023年第5期173-181,共9页
聚酰亚胺(PI)作为高性能聚合物,已成为5G通信的重要原材料之一。传统PI薄膜的介电常数处于3.0~3.4之间,随着电路集成度越来越高,已无法满足高速发展的微电子工业的要求,因此,开发综合性能优异的低介电PI薄膜已成为研究热点。向PI薄膜中... 聚酰亚胺(PI)作为高性能聚合物,已成为5G通信的重要原材料之一。传统PI薄膜的介电常数处于3.0~3.4之间,随着电路集成度越来越高,已无法满足高速发展的微电子工业的要求,因此,开发综合性能优异的低介电PI薄膜已成为研究热点。向PI薄膜中引入微/纳米级的分散孔隙,可以有效降低介电常数,同时保留薄膜优异的综合性能。文中从物理和化学制备方法入手,综述了近年来国内外微/纳米多孔低介电PI薄膜(M/N-PLD-PI)的制备工艺,阐明了引入微/纳米级的分散孔隙对降低PI薄膜介电常数的贡献,并对多孔低介电PI薄膜的发展进行了展望。 展开更多
关键词 微/纳米 低介电常数 多孔材料 聚酰亚胺薄膜 制孔方法
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2015年河北省保定市手足口病病原特征分析 被引量:2
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作者 李娟娟 王玉肖 +7 位作者 周美静 赵灿 苏明 陈妍 郑丽伟 王辉 张亮 倪祥文 《医学动物防制》 2017年第6期639-641,共3页
目的分析2015年保定市手足口病病原分布特征,随访脱甲发生情况,了解不同病原分布对脱甲症的影响。方法采用实时荧光定量聚合酶链反应对病原进行检测,对肠道病毒阳性病例进行随访,从发病后连续观察3个月,筛选脱甲病例。结果 618例阳性病... 目的分析2015年保定市手足口病病原分布特征,随访脱甲发生情况,了解不同病原分布对脱甲症的影响。方法采用实时荧光定量聚合酶链反应对病原进行检测,对肠道病毒阳性病例进行随访,从发病后连续观察3个月,筛选脱甲病例。结果 618例阳性病例中,5岁以下儿童Cox A6和其他肠道病毒交替成为主要病原,而5岁以上儿童则以EV 71为主。Cox A6构成比在北部、南部和中部之间差异不大(χ~2=4.369,P>0.05)。EV 71和Cox A16多集中在南部和中部(χ2=17.300,P<0.05;χ2=6.172,P<0.05),其他肠道病毒则集中在北部和中部(χ~2=15.242,P<0.05)。138例病例出现脱甲,脱甲发生率为22.33%。脱甲组Cox A6病原构成比高于未脱甲组(χ~2=100.856,P<0.05),EV 71、Cox A16及其他肠道病毒病原构成比低于未脱甲组(χ~2=19.724,P<0.05;χ~2=23.305,P<0.05;χ~2=8.855,P<0.05)。结论 Cox A6已成为保定市手足口病的主要病原与手足口病后脱甲症密切相关。 展开更多
关键词 手足口病 病原学 柯萨奇肠道病毒A6 脱甲症
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