The concentrations of Zn, Cd, Pb, Cu ions are shown to be similar in natural waters of Tianshan Mountains and Qinghai-Tibet
plateau and to be similar in those of the sea water. The average and variability of concentraions of trace metal ions in fresh
water are Zn 5.7±1.5, Cd 0.092±0.038, Pb 0.048±0.011, and Cu 1.1±0.20 ppb. The average concentrations in the East China Sea
are Zn 7.3 (5.5 in 1976), Cd 0.12, Pb 0.036, and Cu 0.94 ppb. It proves that the homogeneous distribution of trace metal ions
(free ion and unstable complexes) in natural waters is present in the nature as a rule.
Contribution No. 985 from the Institute of Oceanology, Academia Sinica. 相似文献
The United Nations Sustainable Development Goals (SDG) which launched in 2015 inherited, extended and developed the merits of the United Nations Millennium Development Goals (MDG) in 2000. By the analysis of SDG goals, it can be found that SDG has mainly covered the securities of food supplies, disease prevention, social justice and human rights, the securities of water, energy, land and eco-environment. It covers the human, social, economic, and eco-environmental dimensions. To achieve it, the SDG should be localized and coordinated with the long-term development strategies of Chinese government. And the goals should be integrated into the policies and engineering projects of China simultaneously. By multilaterally cooperating with international communities and sharing the development experiences of other countries/regions, and confronting global issues together, the SDG can be achieved eventually by all the countries of the world. 相似文献
在20世纪90年代,Lehrmann等把中国南方贵州省南部罗甸地区早三叠世的一个孤立的"罗甸碳酸盐岩台地",称作"大贵州滩"。在国外,已有300多篇文章引用"大贵州滩"这一术语。笔者等曾对中国南方早及中三叠世的岩相古地理进行过研究,根据我们的地质资料,在贵州省南部的罗甸地区,在早三叠世,只有一个孤立的"罗甸碳酸盐岩台地",没有"大贵州滩",也不能把"罗甸碳酸盐岩台地"称作"大贵州滩"。《古地理学报》(英文版)2015年第4卷第1期,刊登了冯增昭等的文章,There was no"Great Bank of Guizhou"in the Early Triassic in Guizhou Province,South China(中国南方贵州省早三叠世没有"大贵州滩")。本文是该英文文章的详细摘要,目的在于让国内的广大读者也知道:"大贵州滩"这一术语是严重的名不副实,不应继续使用。 相似文献
Natural Hazards - Rainfall intensity or depth estimates are vital input for hydrologic and hydraulic models used in designing drainage infrastructures. Unfortunately, these estimates are... 相似文献
Natural Hazards - On September 7, 2017, a slope failure occurred in Zhimei village, Chengduo County, Qinghai Province, China. This event involved the failure of 2.4?×?104 m3 of... 相似文献
Viscoelastic artificial boundaries are widely adopted in numerical simulations of wave propagation problems. When explicit time-domain integration algorithms are used, the stability condition of the boundary domain is stricter than that of the internal region due to the influence of the damping and stiffness of an viscoelastic artificial boundary. The lack of a clear and practical stability criterion for this problem, however, affects the reasonable selection of an integral time step when using viscoelastic artificial boundaries. In this study, we investigate the stability conditions of explicit integration algorithms when using three-dimensional (3D) viscoelastic artificial boundaries through an analysis method based on a local subsystem. Several boundary subsystems that can represent localized characteristics of a complete numerical model are established, and their analytical stability conditions are derived from and further compared to one another. The stability of the complete model is controlled by the corner regions, and thus, the global stability criterion for the numerical model with viscoelastic artificial boundaries is obtained. Next, by analyzing the impact of different factors on stability conditions, we recommend a stability coefficient for practically estimating the maximum stable integral time step in the dynamic analysis when using 3D viscoelastic artificial boundaries.