六价铬污染对小白菜产量、养分吸收及若干生理指标的影响

重金属铬的污染严重抑制小白菜的生长,铬的控制指标一般是根据小白菜的减产程度而得以确立的.本文讨论了六价铬污染对小白菜叶片光合作用、营养元素含量,细胞膜透性、超氧化物歧化酶(SOD)活性、过氧化氢酶(CAT)活性以及过氧化物酶(POD)活性的影响.这一工作旨在为客观地制定铬污染的控制标准提供基础和参证.     

一个适用于中距离范围的湍流扩散型

从最简单的二阶闭合假设导出的物质连续方程出发。用近几年来整个行星边界层(PBL)的实测平均风,湍流统计量和拉氏时间尺度随高度和稳定度变化的新结果。对定常的三维方程作数值解,得到一适用于中距离范围的湍流扩散型。该扩散型由纯湍流,地面有效粗糙度,风向切变以及气象参数垂直切变引起的σy随高度和σx随横风方向变化等四个因子组成。在10—100km范围内,扩散型与实测资料和现有的理论扩散型有相当好的一致性。本文的结果无论对PBL内扩散本质的认识还是中距离范围污染模式的建立均有益处。     

藻引发水中偶氮染料的光降解

随着染料工业的发展，染料废水污染也日益严重。目前各国学者也找到了很多处理水中有机物、治理染料废水的办法，但大多局限于腐殖质、过渡金属离子等非生命物质对染料溶液的光降解，本文研究了鱼腥藻、小球藻对几种偶氮染料的光降解情况，并探讨了影响藻对染料溶液光降解的因素。结果显示，pH＝3时，藻能引发水中染料产生明显的光降解，提高藻的浓度，增加光强，均能加快染料的光降解。本文可为利用水体生物资源治理染料废水提供借鉴和帮助。     

佛坪三官庙地区大熊猫种群数量的DNA指纹分析

应用同位素标记大熊猫基因指纹探针Ｆ２ＺＧＰ９６０６０８０１，以秦岭南坡中段佛坪国家级大熊猫自然保护区三官庙范围内采集的大熊猫粪便样品作材料，进行了ＤＮＡ指纹检测．（１）在相同或不同时间、领域采得的粪便样品，显现出相同或不同的ＤＮＡ指纹图谱，达到个体认定的目的，进一步表明了大熊猫的尽量新鲜的粪便，可以作为ＤＮＡ指纹分析材料，进行野生种群数量调查．（２）根据检测２１个粪便样品的结果，无误地认定了三官庙地区有１３只大熊猫个体．其中有３个家系．（３）大熊猫粪便样品的ＤＮＡ指纹图，通过微机识别的个体数，准确可靠，能获得大熊猫在野外的真实个体数量．     

Fe(III)-oxalate complexes induced photooxidation of diethylstilbestrol in water

In this work, the photooxidation of diethylstilbestrol (DES), a synthetic estrogen, was investigated in a concentric reactor under a 125 W high-pressure mercury lamp (lambda > or = 365 nm). The photooxidation efficiencies were dependent on the pH values and Fe(III)/oxalate ratios of the system, with higher efficiency at pH 3.50+/-0.05 and Fe(III)/oxalate ratio 10.0/120.0 micromol l(-1). The photooxidation reactions obeyed the law of pseudo-first-order reaction at the concentration over the range of 2.0-10.0 mg l(-1) of DES. The photooxidation rates decreased with increasing the initial concentrations of DES. For 2.0 mg l(-1) DES, the observed photooxidation rate coefficient (k(obs)) was 0.00622 min(-1). By using GC-MS and LC-MS techniques, the predominant photooxidation products DES-o-catechol ([M](+), m/z 284) and DES-4-semiquinone ([M](-), m/z 267) were respectively identified and the mechanisms for the oxidative degradation were proposed. When DES reacted with OH radicals, C atoms in 3-position were added with OH radicals to produce hydrolyzed DES radical followed by two oxidation pathways: (1) dehydrolyzing to produce DES-4-semiquinone which was oxidized further to DES-4,4'-quinone; (2) undergoing peroxidation by O(2) and getting rid of HO(2) radical to produce DES-o-catechol. After that, the two H atoms on the hydroxy group of the catechol were extracted in two individual steps to form intermediates semiquinone radical and o-quinone. The catechol intermediates underwent further oxidation, benzene ring cleavage and decarboxylation, up to mineralization ultimately.     

燃煤手烧锅炉除尘器的研究与开发

介绍了一种集多种湿法除尘技术之长于一体的新型组合式除尘装置，该装置不仅能有效地消除手烧锅炉燃烧时产生的烟尘，而且实现了除尘水的内循环，消除了其他湿式除尘器所带来的水的二次污染问题。     

错流式动态膜-生物反应器中污泥活性的研究

应用错流式动态膜-生物反应器（CDMBR）对己内酰胺废水进行了180d的实验，实验过程中测定反应器的膜出水和上清液的水质，并对污泥进行了耗氧呼吸速率测定。结果表明，上清液COD一直保持在100mg／L以下，而膜出水的则保持在50mg／L以下，膜对上清液的COD去除率达50％，而对氮的去除没有贡献。可溶性细胞产物（SMP）在反应器内容易积累，停留足够的时间后能被生物降解。通过投加抑制剂测定耗氧呼吸速率，发现异养菌、硝化细菌和亚硝化细菌的活性由于F／M的降低和SMP积累受到一定的抑制，但不影响系统的处理效率。跨膜压力、膜面流速越大，通量衰减得也就越快。     

Spatio-temporal patterns and driving forces of urban land expansion in China during the economic reform era

Along with its economic reform, China has experienced a rapid urbanization. This study mapped urban land expansion in China using high-resolution Landsat Thematic Mapper and Enhanced Thematic Mapper data of 1989/1990, 1995/1996 and 1999/2000 and analyzed its expansion modes and the driving forces underlying this process during 1990-2000. Our results show that China's urban land increased by 817 thousand hectares, of which 80.8% occurred during 1990-1995 and 19.2% during 1995-2000. It was also found that China's urban expansion had high spatial and temporal differences, such as four expansion modes, concentric, leapfrog, linear and multi-nuclei, and their combinations coexisted and expanded urban land area in the second 5 y was much less than that of the first 5 y. Case studies of the 13 mega cities showed that urban expansion had been largely driven by demographic change, economic growth, and changes in land use policies and regulations.     

Electrokinetic remediation of a Cu contaminated red soil by conditioning catholyte pH with different enhancing chemical reagents

The effect of enhancement reagents on the efficiency of electrokinetic remediation of Cu contaminated red soil is evaluated. The enhancement agents were a mix of organic acids, including lactic acid+NaOH, HAc-NaAc and HAc-NaAc+EDTA. The soil was prepared to an initial Cu concentration of 438 mgkg(-1) by incubating the soil with CuSO4 solution in a flooded condition for 1 month. Sequential extraction showed that Cu was partitioned in the soil as follows: 195 mgkg(-1) as water soluble and exchangeable, 71 mgkg(-1) as carbonate bound and 105 mgkg(-1) as Fe and Mn oxides. The results indicate that neutralizing the catholyte pH maintains a lower soil pH compared to that without electrokinetic treatment. The electric currents varied depending upon the conditioning solutions and increased with an increasing applied voltage potential. The electroosmotic flow rate changed significantly when different conditioning enhancing reagents were used. It was observed that lactic acid+NaOH treatments resulted in higher soil electric conductivities than HAc-NaAc and HAc-NaAc+EDTA treatments. Ultimately, enhancement by lactic acid+NaOH resulted in highest removal efficiency (81% Cu removal) from the red soil. The presence of EDTA did not enhance Cu removal efficiencies from the red soil, because EDTA complexed with Cu to form negatively charge complexes, which slowly migrated toward the anode chamber retarding Cu2+ transport towards the cathode.     

调理剂对CAF污泥浓缩工艺影响的试验研究

涡凹气浮（CAF）已广泛应用于工业废水和城市污水的预处理中.由于污泥本身的特性原因,CAF在污泥处理中尚没有应用.通过试验投加污泥调理剂改变污泥的特性,以达到将CAF工艺用于浓缩活性污泥的目的.试验表明,CAF工艺浓缩低浓度剩余活性污泥效果很好,但正确选择污泥调理剂的投加点和投加量对CAF污泥浓缩工艺至关重要.