矿山含铜酸性废水硫化沉淀过程中硫化氢产生量的控制

对矿山含铜酸性废水硫化沉淀的过程进行了理论分析和实验研究,并提出了控制硫化氢气体产生量的措施。实验结果表明:在矿山含铜酸性废水硫化沉铜过程中,硫氢化钠被Fe³⁺还原成单质硫的反应最容易发生,其次为硫氢化钠与Cu²⁺生成CuS沉淀的反应,产生硫化氢气体的趋势很弱,而生成FeS的趋势最弱;当反应终点电位控制在200 mV时,铜基本上沉淀完全,铁沉淀率很小;硫氢化钠的过剩量较小,可在最大程度上减少硫化氢气体的产生量;随着溶液酸度增加,硫化氢气体的产生量逐渐增加。硫化沉淀反应体系的硫酸质量浓度宜控制在小于4 g/L。     

Sediment Flux to the Sea as Influenced by Changing Human Activities and Precipitation: Example of the Yellow River,China

Since the 1970s, the sediment flux of the Yellow River to the sea has shown a marked tendency to decrease, which is unfavorable for wetland protection and oil extraction in the Yellow River delta. Thus, an effort has been made to elucidate the relation between the sediment flux to the sea and the drainage basin factors including climate and human activities. The results show that the sediment flux to the sea responds to the changed precipitation in different ways for different runoff and sediment source areas in the drainage basin. If other factors are assumed to be constant, when the annual precipitation in the area between Longmen and Sanmenxia decreases by 10 mm, the sediment flux to the sea will decrease by 27.5 million t/yr; when the precipitation in the area between Hekouzhen and Longmen decreases by 10 mm, the sediment flux to the sea will decrease by 14.3 million t/yr; when the precipitation in the area above Lanzhou decreases by 10 mm, the sediment flux to the sea will decrease by 17.4 million t/yr. A multiple regression equation has been established between the sediment flux to the sea and the influencing factors, such as the area of land terracing and tree and grass planting, the area of the land created by the sediment trapped by check dams, the annual precipitation, and the annual quantity of water diversion by man. The equation may be used to estimate the change in the sediment flux to the sea when the influencing variables are further changed, to provide useful knowledge for the environmental planning of the Yellow River drainage basin and its delta.     

Comparison of Solid-Phase and Pore-Water Approaches for Assessing the Quality of Marine and Estuarine Sediments

As part of our continuing evaluation of the pore-water approach for assessing sediment quality, we made a series of side-by-side comparisons between the standard 10-day amphipod whole sediment test with the corophiid Grandidierella japonica and a suite of tests using pore water extracted from the same sediments. the pore-water tests evaluated were the sea urchin (Arbacia punctulata) sperm cell test and morphological development assay, the life-cycle test with the polychaete Dinophilus gyrociliatus, and acute exposures of red drum (Sciaenops ocellatus) embryo-larval stages. Sediment and surface microlayer samples were collected from contaminated sites. Whole-sediment, pore-water, and surface microlayer toxicity tests were performed. Pore-water toxicity tests were considerably more sensitive than the whole-sediment amphipod test, which is currently the most sensitive toxicity test now recommended for determining the acceptability of dredged material for open ocean disposal.     

Radioactivity Monitored From Moored Oceanographic Buoys

The principles and operation of a gamma radiation sensor mounted on oceanographic buoys are described. the sensor has proved rugged in severe weather conditions and has satisfactory detection limits and accuracy. Continuous monitoring of artificially produced γ-emitters such as ¹³⁷Cs, ¹³⁴Cs, ¹³¹I, ¹³³I, ¹³²Te, naturally occuring emitters such as ⁴⁰k and ²¹⁴Bi in open sea conditions can provide important information in critical situations.     

岸滩侵蚀的环境工程观念

本文从环境工程的角度讨论了岸滩侵蚀问题中建立分析模型的基本框架.讨论了岸滩岩土介质在风浪潮作用下,根据不同的侵蚀准则所建立的岸滩沉积物在近海迁移和传输的模型.得出了岸滩的侵蚀、演变过程由三相组成的结论,第一相是与饱和多孔介质经受动力载荷变形和损伤相联系的固态相;第二相是关于介质侵蚀和剥离的流-固态混合相;第三相是流动和沉积物运输的流体相.从分析讨论还可以看出,岸滩侵蚀演化的模拟分析可在岸滩介质的动力固结、悬浮介质扩散漂移及海浪流体动力学理论相互交叉的基础上,针对海岸环境工程问题中的观念和现象来建模并完成.研究表明,在分析海滩侵蚀和海岸演化过程的机理时,采用海洋环境工程学中的相关方法可以得到更符合实际状况的结果.用损伤力学方法建摸研究岸滩介质的侵蚀和沙化过程,可以将海岸沉积物的迁移速率描述为海床面上的等效摩擦剪应力、损伤状态、侵蚀参数及介质的孔隙冲蚀率的函数.在岸滩侵蚀和演化机理研究中将海岸沉积物的纵向迁移和横向迁移理论相结合的模型有一定的优越性,这为岸滩侵蚀与海岸演变提供了定量的分析方法.     

热带海—气的相互作用与地球自转—用天文方法预测ENSO事件

本文介绍了热带海洋、大气的相互作用,着重描述了它们与地球自转年际速率变化的关系和物理过程的联系,以及用天文观测的日长变化资料预测ENSO事件的方法和尝试.     

海洋溢油和含油废水排放的对策

海洋是人类赖以生存的第二大场所。开发海洋石油资源必须做到既要把石油资源开采出来，又要保护海洋生态环境不遭受污染。概述了溢油的污染机理、计算方法、预防措施。     

土壤氧化还原电位测定方法的探讨与研究

是选用铂电极直接测定法来测定土壤的氧化还原电位,该方法是采用铂电极作为氧化还原电极,饱和甘汞电极作为参比电极,两者之间存在电位差的原理而测得的。通过大量的试验数据,表明该方法是简便易行的,对于一般的土壤都有实际参考价值。最后,对此过程中遇到的问题进行了深入的探讨和研究,并提出了具体解决方案。     

细菌偶氮还原研究进展

细菌偶氮还原是在细菌偶氮还原酶作用下偶氮复合物分解为芳香氨的过程,多种细菌都具有偶氮还原功能.有氧条件下细菌的偶氮还原是在特异性的偶氮还原酶作用下完成的,对氧气不敏感.而厌氧菌和兼性厌氧菌的偶氮还原是在厌氧或兼性厌氧条件下由一些氧化还原中间体作为电子穿梭体与偶氮复合物作用的非特性的还原过程.电子穿梭体与偶氮复合物作用是一个纯化学氧化还原过程,其中偶氮复合物作为电子受体接受电子.厌氧偶氮还原是细菌偶氮还原的主要形式.偶氮还原在厌氧-好氧染料废水处理系统和偶氮水溶胶聚合物作为结肠靶向给药载体的研究中有重要应用.图2表1参45     

Similarity theory and parameterization of mixing in the upper ocean

Boundary layers with small thermal and mechanical inertia are close to steady-state conditions. This underlies the Monin-Obukhov similarity theory and explains why the surface values of the fluxes can be chosen as external parameters. For fluids with large thermal inertia, such as the ocean, the thermal time scale is relatively large, and the density flux is a complex function of depth; thus, the external thermal forcing is no longer a governing parameter. However, the mechanical inertia of the upper ocean is about three orders of magnitude smaller than the thermal inertia. Consequently, the upper ocean can be considered as steady-state in the dynamic sense, to any dynamic property depends primarily on the depth, the surface momentum flux, and the vertical density structure. This property allows us to suggest an alternative formulation of the similarity theory for the stratified boundary layers through specification of a new stratification parameter which characterizes the internal density structure instead of the external density flux. The turbulent mixing coefficient is derived as dependent on the stratification parameter. The latter includes the surface stress and the integral density deficit for the entire layer above. The general form and the asymptotic behavior of the nondimensional turbulent mixing coefficient as a function of the stratification parameter are obtained using dimensional considerations. Determination of numerical parameters is based on 8 years of temperature profiles acquired at the Ocean Weather Ship (OWS) PAPA. Finally, a method for calculating the profile of the turbulent mixing coefficient is obtained. This approach reproduces the 8-year evolution of the upper ocean with the maximum rms difference of approximately 1C and the bias of 1C over the depth range 0–150 m. Additional 1-year simulation of the upper ocean at OWS CHARLEY and 9-year simulation at OWS NOVEMBER confirms reasonable applicability of this approach. The proposed simple turbulent mixing scheme reproduces the evolution of the upper ocean with accuracies similar to those obtained using much more complicated models.