淮河支流污染物综合降解系数动态测算

确定河流污染物综合降解系数动态变化规律对提高水环境容量测算精度和水环境管理具有重要意义。通过现场模拟法,采用一维稳态模型测算了淮河支流洪河五沟营-塔桥乡河段COD、氨氮和总磷在枯水期、平水期和丰水期的综合降解系数,COD、氨氮和总磷降解系数在各水期的关系为枯水期平水期丰水期,提出了建议值并利用实测浓度对计算结果进行了检验,结果表明,不同水期综合降解系数吻合情况较好。     

A multi-path routing-inventory problem for a closed-loop supply chain considering the heterogeneous fleet of vehicles

In this paper, the inventory-routing problem is studied for a closed-loop supply chain. This closed-loop supply chain considers suppliers, manufacturers, whole-sellers, and disposal centers. To formulate this problem, a mixed integer linear programming model is proposed. This mathematical model minimizes the total costs of the supply chain, including the fixed and variable costs of vehicles, and holding inventory costs of final products and scraps. The proposed model considers the road roughness degree, multi-path setting and the heterogeneous fleet of vehicles, which increases its flexibility and the quality of solutions. Then, two symmetry-breaking constraints are proposed to reduce the complexity of the mathematical model. In order to evaluate the integrity of the proposed model, 20 instances of different sizes are randomly generated and solved. Finally, a comprehensive sensitivity analysis is conducted with respect to five key features of the problem, such as the impact of the symmetry-breaking constraints on the CPU time, multi-path setting, fixed cost of vehicles, heterogeneous fleet of vehicles, and lost sales. The results indicate that the consideration of multi-path setting and the heterogeneous fleet of vehicles improves the quality of solutions significantly.     

Experience in quantitative analysis of floristic structure and diversity in Samarskaya Luka

Quantitative methods have been applied to the study of floristic structure and diversity in Samarskaya Luka. The results show that Samarskaya Luka is a floristically heterogeneous area in which six elementary floras can be distinguished. This area has been assessed as a floristically autonomous formation, and its floristic representativeness was estimated.     

Dust Storms are an Indication of an Unhealthy Environment in East Asia

Dust storms frequently occur in Mongolia and in northern China. Each year there are 30 to 120 dusty days in source regions of Mongolia and 14–20 dusty days on the Korean Peninsula. Intense sand storms and associated dust falls produce environmental impacts in East Asia. This paper discusses the environmental degradation in Mongolia and the social, economic and atmospheric impacts of dust storms in the sink area. The impact of dust storms on environmental compartments as well as their direct and indirect consequences to basic resources like water and energy demand and supply is explained. Governments are encouraged to take appropriate action in specified regions. For monitoring dust storms there is a need for international cooperation to combat growing environmental and human security concerns.     

Eco-Environmental Degradation in the Source Region of the Yellow River, Northeast Qinghai-Xizang Plateau

The Yellow River is the second longest river in China and the cradle of the Chinese civilization. The source region of the Yellow River is the most important water holding area for the Yellow River, about 49.2% of the whole runoff comes from this region. However, for the special location, it is a region with most fragile eco-environment in China as well. Eco-environmental degradation in the source region of the Yellow River has been a very serious ecological and socially economic problem. According to census data, historical documents and climatic information, during the last half century, especially the last 30 years, great changes have taken place in the eco-environment of this region. Such changes are mainly manifested in the temporal-spatial changes of water environment, deglaciation, permafrost reduction, vegetation degeneracy and desertification extent, which led to land capacity decreasing and river disconnecting. At present, desertification of the region is showing an accelerating tendency. This paper analyzes the present status of eco-environment degradation in this region supported by GIS and RS, as well as field investigation and indoor analysis, based on knowledge, multi-source data is gathered and the classification is worked out, deals with their natural and anthropogenic causes, and points out that in the last half century the desertification and environmental degradation of this region are mainly attributed to human activities under the background of regional climate changes. To halt further degradation of the environment of this region, great efforts should be made to use land resources rationally, develop advantages animal agriculture and protect the natural grassland.     

燃煤电厂海水烟气脱硫工艺原理初探

海水烟气脱硫工艺是利用天然的纯海水（燃煤电厂可直接利用电厂的冷却循环水）作为烟气中ＳＯ２的吸收剂，无需其它任何添加剂，也不产生任何废弃物，具有技术成熟、工艺简单、系统运行可靠、脱硫效率高（理论脱硫效率可达９８％）和投资运行费用低等特点，目前在一些国家和地区已得到日益广泛的应用。本文是在部分模拟试验的基础上，对海水烟气脱硫工艺进行了简单的阐述。     

三峡库区水土流失特点及其环境危害防治措施探讨

水土流失是三峡库区主要环境问题之一,也是库区产生大量泥沙的根本因素,更是造成库区人民生活贫困的根源。本文就三峡库区水土流失的特点及其环境危害作了分析,提出了相应的防治措施,为水土流失防治工程提供科学依据。     

湖北省2008年初低温雨雪冰冻过程气候特征分析

2008年初，湖北省出现了严重的低温雨雪冰冻灾害，直接经济损失高达110亿元以上，有必要对灾害期间的气候特征进行系统、科学的分析和总结。对湖北省76个气象站2008年1月12日～2月3日气温、降水（雪）、日照以及低温持续日数等要素进行时空间差异分析及历史与同期比较，并选取10个代表站历史上所有低温雨雪天气过程，对其过程持续低温日数、最长连续雨雪日数、过程极端低温进行比较分析。结果表明：（1）此次过程的平均气温异常偏低，该省大部为-1～-2℃，比常年同期偏低4～6℃，为各站历史同期最低，其中主要是最高气温异常偏低所致，但极端低温并不低；（2）降雪过程频繁，雨雪量异常偏多；（3）低温冰冻持续时间长，该省大部在16～22 d，位于历史第一；（4）日照异常偏少。持续而稳定的大气环流异常形势是湖北省大范围低温雨雪天气的直接原因。     

Pre-concentration and separation of heavy metal ions by chemically modified waste paper gel

Iminodiacetic acid was immobilized on waste paper by chemical modification in order to develop a new type of adsorption gel for heavy metal ions. Adsorption behavior of the gel was investigated for a number of metal ions, specifically Cu(II), Pb(II), Fe(III), Ni(II), Cd(II), and Co(II) at acidic pH. From batch adsorption tests, the order of selectivity was found to be as follows: Cu(II)  Fe(III) > Pb(II) > Ni(II)  Co(II) > Cd(II). Column tests were carried out for pairs of metal ions to understand the separation and pre-concentration behavior of the gel. It was found that mutual separation of Ni(II) from Co(II) and that of Pb(II) from Cd(II) can be achieved at pH 3. Similarly, selective separation of Cu(II) from Cu(II)–Fe(III) and Cu(II)–Pb(II) mixtures at pH 1.5 and 2, respectively, was observed by using this new adsorption gel. In all cases, almost complete recovery of the adsorbed metal was confirmed by elution tests with HCl.