Development of methods for establishing nutrient criteria in lakes and reservoirs: A review

Nutrient criteria provide a scientific foundation for the comprehensive evaluation, prevention,control and management of water eutrophication. In this review, the literature was examined to systematically evaluate the benefits, drawbacks, and applications of statistical analysis,paleolimnological reconstruction, stressor-response model, and model inference approaches for nutrient criteria determination. The developments and challenges in the determination of nutrient criteria in lakes and reservoirs are presented. Reference lakes can reflect the original states of lakes, but reference sites are often unavailable. Using the paleolimnological reconstruction method, it is often difficult to reconstruct the historical nutrient conditions of shallow lakes in which the sediments are easily disturbed. The model inference approach requires sufficient data to identify the appropriate equations and characterize a waterbody or group of waterbodies, thereby increasing the difficulty of establishing nutrient criteria. The stressor-response model is a potential development direction for nutrient criteria determination, and the mechanisms of stressor-response models should be studied further. Based on studies of the relationships among water ecological criteria, eutrophication, nutrient criteria and plankton, methods for determining nutrient criteria should be closely integrated with water management requirements.     

The effect of vent size and concentration in vented gasoline-air explosions

Experimental data from vented explosion tests using gasoline-air mixtures with concentrations from 0.88 to 2.41% vol. are presented. A 2L vessel was used for the tests with vent sizes of 25 cm², 50 cm² and 100 cm². The tests were focused on the effect of gasoline vapor concentration and vent size on the pressure development and the flame behavior inside and outside the vessel. It was found that the inner flame propagation speed was mainly dependent on the initial concentration, while the maximum flame spreading distance was mainly influenced by the vent size. The external flame speed and duration could be influenced by the combination of the two properties. The internal pressure increases gradually with the flame propagated inside the vessel and decreased sharply when the vent failed. High-pressure durations containing pressure peaks were recorded by transducers in front of the vent and oscillations could be observed besides the vent. At any measure point, the maximum external pressures for A = 25 cm² or 50 cm² were significantly larger than those for A = 100 cm².     

基于LIMS数据库的环境监测数据统计方法——以上海市嘉定区实验室信息系统为例

实验室信息管理系统(Laboratory Information Management System,LIMS)在环境监测领域中,已经逐渐地得到了普及,在LIMS数据库中涵盖了大量的环境监测信息和数据,与传统的数据统计方法相比,通过SQL语句对LIMS数据库进行SELECT操作,能够大大提高统计的效率和准确性。     

复合垂直流人工湿地氧化还原特征及不同功能区净化作用研究

研究了复合垂直流人工湿地系统氧化还原电位（Eh）的时空变化规律及不同功能区中污染物的净化效果。结果表明：湿地系统下行流池表层、两池底层、上行流池表层Eh的变化范围分别为402～585、-87～-130、308～432 mV，沿水流方向依次形成了好氧A区/缺氧、厌氧区/好氧B区3个功能区。好氧A区是污染物去除的主要区域，BOD₅、COD_Cr、NH⁺_4- N的去除率分别为430%、484%、541%，特别是NH+4 N去除率占总去除率的79%；缺氧、厌氧区主要是进行反硝化反应和有机物的厌氧分解；好氧B区则主要是去除厌氧分解后的有机物以及进一步脱氮。另外，NH+4 N的去除率与系统各功能区Eh呈显著相关关系（〖WTBX〗p〖WTBZ〗＜001），而BOD₅、COD_Cr、NO^-_3-N的去除率与系统各功能区Eh相关性不显著。     

1994／1995全球重大自然灾害的统计分析

１９９４／１９９５年是６０年代以来全球自然灾害经济损失最大的两年。作者根据收集到的信息，对全球这两年的重大自然灾害的分布及灾情作了统计。结果表明，９０年代全球重大自然灾害的经济和保险损失存在上升趋势。最后，对其成因进行了分析     

What do significance tests really tell us about the environment?

Routine application of significance tests does not extract the maximum information from environmental data and can lead to misleading conclusions. Reasons leading to this are: a significant result can often be reached merely by collecting enough samples; a statistically significant result is not necessarily practically significant; and reports of the presence or absence of statistically significant differences for multiple tests are not comparable unless identical sample sizes are used. These problems are demonstrated by application to pH data for grazed and retired fields, and by discussion of significance tests used in recent US regulations for groundwater quality. The advantages of equivalence tests, where the tester must state the difference of practical difference, are discussed and applied to the field pH problem. We recommend that environmental managers and scientists pay more attention to statistical power and decide on what is a practical difference. Confidence intervals for the size of the differences, accompanied where necessary by equivalence tests, are the preferred means of addressing the question: “is there a difference of practical significance?”     

SBR法废水处理技术分析

本文介绍了ＳＢＲ法处理原理及特点,使用该工艺所需设备和监测手段,应用前景。证明了ＳＢＲ法适应性强,处理效果好,投资动行成本低,是一种经济、实用的污水处理工艺。     

苏州地区有关南黄海6.1级地震的前兆异常特征及预报检验

根据对南黄海６．１级地震前，苏州地区１９９５年９月～１９９６年１０月以地下水动态、地下水化学为主的前兆异常的分析，预报了这次地震，并对其进行了检验及原因分析     

中国近五百年流域性洪涝统计特征研究

本文以《中国近五百年旱涝分布图集》为基础，并将资料适当延长，提出了流域性洪涝及其指标。在此基础上，初步分析了我国主要流域单元近５００年（１４７０￣１９９１年）和各世纪流域性洪涝事件发生折频次和持续性，并分析了南方、北方和全区域主要流域单元不同等级流域性洪涝空间遭遇的可能性。     

新疆河流径流特征分析

选择了新疆众多河流中代表性好的7条河流，对径流的特征进行了分析。结果表明，新疆河流径流量主要集中在夏季，占年径流量的50．8％—70．7％，春、秋季径流量差别不大，冬季仅占年径流量的4．7％—10．8％。以7条河流径流深值可看出，北疆径流深值比南疆大，最大的是布尔津河，径流深为507．4mm。从径流量的Cv值看，除头道沟为0．44，极值比4．42较大外，其它河流的Cv值均在0．19—0．23间、极值比在1．85—2．42间。同时，新疆大多数河流径流量90年代后有明显增多的趋势。