期刊文献+
共找到5篇文章
< 1 >
每页显示 20 50 100
涡北煤矿外围农田玉米重金属污染特征及健康风险评价 被引量:9
1
作者 陈亚婷 李家莹 +5 位作者 何情 郑硕 安燕飞 汪宏志 程晋 叶凌峰 《环境化学》 CAS CSCD 北大核心 2022年第2期526-535,共10页
为全面了解涡北煤矿外围农田玉米重金属污染现状,本文测定了玉米籽粒及对应土壤样品的重金属含量,运用单因子及综合污染指数分析重金属在玉米籽粒中的污染状况,并采用美国EPAMMSOILS风险评价模型评价了摄食玉米对人体造成的重金属健康风... 为全面了解涡北煤矿外围农田玉米重金属污染现状,本文测定了玉米籽粒及对应土壤样品的重金属含量,运用单因子及综合污染指数分析重金属在玉米籽粒中的污染状况,并采用美国EPAMMSOILS风险评价模型评价了摄食玉米对人体造成的重金属健康风险.结果表明,研究区玉米籽粒中Ni、As、Cr、Zn、Cu、Cd和Pb的平均含量分别为0.73、0.11、0.81、23.76、2.09、0.01、0.23 mg·kg^(-1),除Ni和Pb外,其它重金属含量均值均未超过我国食品卫生标准.综合污染指数显示Ni和Pb为4.26和4.44,属于重度污染,Cr则介于1—2之间,属于轻度污染,Cd、Cu、As、Zn都小于1,表明无污染.Ni、Cr、Cd和Pb的含量空间分布均呈现东南向西北递增的趋势.As对儿童的健康风险指数大于1,其它6种重金属对儿童的健康风险指数小于1,各重金属对成人的健康风险较小,另外,重金属复合污染对儿童存在健康风险,所以居民通过摄食玉米产生的健康风险应该引起关注. 展开更多
关键词 重金属 健康风险 玉米籽粒 涡北煤矿
原文传递
Flavones Isolated from Codonopsis xundianensis 被引量:25
2
作者 heqing ZHUEn-yuan +2 位作者 WANGZheng-tao XULuo-shan HUZhi-bi 《Journal of Chinese Pharmaceutical Sciences》 CAS 2004年第3期212-213,共2页
Genus Codonopsis comprises more than 40 species in China. The roots of these plants have been used as traditional Chinese medicines or folk love herbs. Codonopsis xundianensis Wang ZT et Xu GJ grows in Yunnan Province... Genus Codonopsis comprises more than 40 species in China. The roots of these plants have been used as traditional Chinese medicines or folk love herbs. Codonopsis xundianensis Wang ZT et Xu GJ grows in Yunnan Province and its roots are often used as a tonic. In this paper, we report the isolation and structural elucidation of chrysoeriol (1), tricin (2), wogonin (3) and luteolin (4) from the roots of Codonopsis xundianensis. Compounds 1-3 were found in Codonopsis for the first time. 展开更多
关键词 FLAVONE CHRYSOERIOL TRICIN WOGONIN LUTEOLIN codonopsis xundianensis
暂未订购
非重叠域行人再识别算法研究 被引量:2
3
作者 何晴 郭捷 《信息技术》 2018年第7期34-38,共5页
随着多摄像头监控系统的广泛应用,非重叠域中行人目标的再识别成为智能视频监控研究的热门领域。目前,非重叠域行人再识别的研究主要集中在两个方面:特征提取和度量学习。文中提出了一种基于深度卷积生成对抗网络(DCGAN)的行人再识别方... 随着多摄像头监控系统的广泛应用,非重叠域中行人目标的再识别成为智能视频监控研究的热门领域。目前,非重叠域行人再识别的研究主要集中在两个方面:特征提取和度量学习。文中提出了一种基于深度卷积生成对抗网络(DCGAN)的行人再识别方法,该方法训练DCGAN网络来提取特征,DCGAN网络包括两个部分:生成模型G,判别模型D,训练过程中通过两个模型的对抗,可以得到行人图片更具区分性的特征描述,然后根据提取的特征进行相似性度量,判断是否是同一个行人。实验结果表明该方法对于非重叠域的行人再识别具有一定效果,而且可以消除清晰度、光照、遮挡等的负面影响,具有一定的鲁棒性。 展开更多
关键词 行人再识别 卷积神经网络 生成对抗网络
在线阅读 下载PDF
RAPD Technique Used to Determine the Purity of Hybrid Hot Pepper Seeds 被引量:2
4
作者 ZhouQunchu heqing +3 位作者 MaYanqing ZhangZouqing LiXuefeng AiXin 《Hunan Agricultural Science & Technology Newsletter》 2000年第1期19-21,共3页
Two hybrid hot pepper varieties Xiangyan 5 and Xiangyan 10, and their parents were analyzed the polymerase chain reaction with MJ /PT 200 Peltrier Themal Cycler and DS 800 White-ultravilot Transilluminator to set up a... Two hybrid hot pepper varieties Xiangyan 5 and Xiangyan 10, and their parents were analyzed the polymerase chain reaction with MJ /PT 200 Peltrier Themal Cycler and DS 800 White-ultravilot Transilluminator to set up a RAPD system adaptable to the purity determination of the hy-brid seeds. Among the 39 random primers, 2 and 4 primers were found to be used effectively in Xiangyan 5 and Xiangyan 10 respectively. 展开更多
关键词 Hot pepper (Capsicum annum) Randomly amplified polymorphic DNA(RAPD) Purity determination
在线阅读 下载PDF
Variations of the spring precipitation day numbers reconstructed from tree rings in the Urumqi River drainage,Tianshan Mts.over the last 370 years 被引量:50
5
作者 YUANYujiang JINLiya +2 位作者 SHAOXuemei heqing LIZhizhong 《Chinese Science Bulletin》 SCIE EI CAS 2003年第14期1507-1510,共4页
The tree-ring cores of Tianshan spruces collected from nine sites in the Urumqi River drainage of the middle Tianshan Mountains were used to establish three types of the tree-ring width chronologies over the last 370 ... The tree-ring cores of Tianshan spruces collected from nine sites in the Urumqi River drainage of the middle Tianshan Mountains were used to establish three types of the tree-ring width chronologies over the last 370 years, using the international standard method of dendrochronology. Our study demonstrates that dendrochronology can be better used to reconstruct the number of the precipitation day than to reconstruct the precipitation amount in middle Tianshan Mountains. It is found that the residual chronology among the three tree-ring width chronologies has the best relationship with number of spring precipitation days from May 20 to June 8. The chronologies at Haxionggou B site and Zaierdegou site in the Urumiqi drainage have the highest correlation with the observed number of spring precipitation days at Daxigou meteorological station, and are used to reconstruct the spring precipitation days over the last 370 years in the drainage. The main significant decreasing trend of the number of the spring precipitation days occurred during 1665—1717, while the significant increasing trends happened during 1805—1841 and 1914—1943. The reconstructed series of the number of spring precipitation days has quasi-periodic variations of 3.3, 2.1, 2.5, 12.3 and 32.0 years with the dominated short periodical changes. The long cycle of 32 years is shown quite clearly in the 10-year smoothed sequence. The maximum spring precipitation days occurred mainly in the 1630s, 1840s and 1940s, while the lowest number of spring precipitation days for the 10-year average occurred in the 1710s. 展开更多
关键词 天山山脉 乌鲁木齐河流域 春季 降水天数 年轮
在线阅读 下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部