Characteristics and driving factors of marsh changes in Zhalong wetland of China

Zhalong National Nature Reserve in the northeast of China is a large wetland and a habitat of hundreds species of fauna and flora. The rare red-crowned crane is one kind of endangered birds in it. Recently, Zhalong wetland is shrinking and it encounters many problems including occasional fires, bad water quality, human activities, etc. In order to find out a proper way to protect and restore the wetland, this study, using a geographic information system, the global positioning system and remote sensing techniques, analyses the spatial characteristics of the changes in marsh landscape pattern and examines the driving factors for these changes. Data sources include 8 Landsat Thematic Mapper satellite images of Zhalong area in the period of 1986–2002 and the investigation information on site. Based on the analysis of changes of marsh area and annual precipitation during the 16 years, it is found that there is a close correlation between annual precipitation and marsh area. It means that climate is one of driving factors of marsh pattern changes. To understand influences of other kinds of land uses on marsh spatial distribution in Zhalong wetland, this paper analyses the relationship between marsh and different kinds of land uses, such as water surface, residential area, farmland, salina land and grass land, respectively. According to the patch analysis theory, a fragmental index and a fractal dimension of the marsh are calculated with perimeter-area method. The results indicate that the marsh pattern is affected by human activities significantly. In addition, the location alteration of marsh centroid point over the 16 years is studied. The movement trace of marsh centroid point is concerned with different hydrological situation in different areas of the wetland. In summary the characteristics of the marsh landscape pattern evolution during the 16 years are affected by multiple driving factors. The main driving factors are climate, human activities, distribution of other kinds of land uses and hydrological situation in different areas.     

乌鲁木齐市大气环境质量现状及其变化趋势分析

本文对乌鲁木齐市大气环境质量及其发展趋势作了简要的分析,说明目前市大气属煤烟-沙尘型污染区,氮氧化物和二氧化硫随着国民经济能耗的增加有发展的趋势,其它污染物仍稳定在目前水平,或稍有下降.     

二维与三维电解法处理含铜废水的试验研究

以含铜废水为处理对象,考察了二维电解法的电解电压、电解时间、pH值、极间距对铜去除率的影响。在此基础上为提高处理效率,两极间填充活性炭和玻璃珠形成三维电解,确定了三维电解的最佳运行条件是极间距4cm,pH值3～4,电解电压22 V,电解135min,铜离子的去除率为80.6%。     

关于安全投资效益目标函数的建立和优化

通过对安全投资与事故经济损失的规律性的分析研究，确立安全投资与经济效益的内在关系，进一步探索在我国现有财力和安全水平的基础上，找准安全投资的投向，优化安全投资的合理分配，从而实现最大限度地提高企业安全生产水平和安全投资效益。为政府部门或企业提供一套经过优化、科学合理、操作性又比较强的安全投资方案，供各级领导进行安全决策，实现本部门、本单位的安全投资计划时参考     

特警战训服面料开发技术研究

本文介绍了以芳纶纤维为主要材料的我国新一代特警战训服面料的技术研发及达到的主要性能指标。通过试验研究,开发了具有高强防撕裂、永久阻燃、耐高温、防静电、防油拒水、防酸碱等具有集成防护功能的特警战训服系列面料。     

连续采样与五日法采样效果及费用的对比分析

通过对连续采样与五日法采样五种方法监测结果及所需费用的比较，得出连续采样方法监测结果更具有代表性，合理性，一次性投资大，但运行费用并不高的结论。     

镉─邻菲啰啉配合物吸附波的研究与应用

在ｐＨ３．３的盐酸－醋酸钠介质中．镉－邻菲啉配合物在－０．６５Ｖ（ｖＳ．ＳＣＥ）处产生一灵敏的吸附波，其二次导数波高与镉浓度在０．０００６～０．１ｍｇ／Ｌ范围内呈良好的线性关系，检出下限达０．０００３ｍｇ／Ｌ。极谱波性质的研究表明该波具有配合物吸附波的特征。方法已用于环境水样中微量错的测定，结果与其它方法吻合。     

城市污水处理厂二沉池出水曝气混合絮凝的研究

在污水处理厂实验室,对二沉池出口污水进行了曝气和机械2种方式的混合絮凝对比试验。研究结果表明,对于同一水质,在相同的投药量下,曝气混凝沉淀后的水质明显优于机械混凝沉淀后的水质,各项水质指标的去除率分别提高：BOD₅ 6%～9%,COD 4%～6%,NH₃-N 6%～9%,TP 15%～24%,SS 8%～18%。     

氯气泄漏扩散过程及后果评价的研究现状分析

综述了氯气泄漏扩散过程及后果评价的研究成果。从现场试验、实验室模拟和数学模拟三方面分析了氯气泄漏扩散各研究方法的优势和局限性。强调了氯气泄漏扩散后果评价的必要性。指出:必须针对中国特有的一些重气扩散建立专属知识产权的数学模型;不同层次数学模型的精度皆有待于进一步提高;需加强基于特定数学模型的全过程统一界面模拟程序的开发。     

Study of nitrogen oxide absorption in the calcium sulfite slurry

Experiments were conducted using a bubbling reactor to investigate nitrogen oxide absorption in the calcium sulfite slurry. The effects of CaSO₃ concentration, NO₂/NO mole ratio and O₂ concentrations on NO₂ and SO₂ absorption efficiencies were investigated. Five types of additives, including MgSO₄, Na₂SO₄, FeSO₄, MgSO₄/Na₂SO₄ and FeSO₄/Na₂SO₄, had been evaluated for enhancing NO₂ absorption in CaSO₃ slurry. Results showed that CaSO₃ concentration had significant impact on NO₂ and SO₂ absorption efficiencies, and the highest absorption efficiencies of SO₂ and NO₂ could reach about 99.5 and 75.0 %, respectively. Furthermore, the NO₂ absorption was closely related to the NO₂/NO mole ratio, and the existence of NO₂ in flue gas may promote NO absorption. The presence of O₂ in simulated flue gas was disadvantage for NO _x removal because it can oxidize sulfite to sulfate. It was worth pointing out that FeSO₄/Na₂SO₄ was the best additive among those investigated additives, as the NO₂ removal efficiency was significantly increased from 74.8 to 95.0 %. IC and in situ FTIR results suggest that the main products were NO₃ ^? and NO₂ ^? in liquid phase and N₂O, N₂O₅ and HNO₃ in gas phase during the CaSO₃ absorption process.