纳氏试剂法测定水中低浓度氨氮的预处理方法的改进

选用纳氏试剂分光光度法测定氨氮时,比较蒸馏法中分别以硼酸和纯水为吸收液时氨氮的检测效果。结果显示,当氨氮质量浓度1.0 mg/L时,用纯水或硼酸作吸收液均可;当氨氮质量浓度1.0 mg/L时,应以纯水为吸收液。     

Fish assemblages composition in a natural, then regulated, stream: A quantitative long-term study

This paper tests the hypothesis how effectively fish assemblage composition was shaped by local climate changes and by engineering impact in 1989. This was possible due to the monitoring protocols of the present study, which allowed estimation of the magnitude of anthropogenic changes from changes naturally occurring in nature. Fish were sampled at the end of every growing season (October) for 23 years at five contiguous sites in a stream, before (1979-1988) and after (1989-2001) regulation. In each sample, six successive electrofishing passes were used to calculate the density and mean biomass for assemblage analysis using the Zippin model. During the study, the natural, meandering stream with pools, riffles, and a moderate canopy was modified into a straight stream of uniform width and depth, stripped of all vegetation. The output layer of a self-organizing map (SOM, the artificial neural network algorithm) applied in this study for site similarity analysis was partitioned into six subclusters placed in two main clusters. Subclusters in the upper part of the SOM were occupied chiefly by regulated stream samples and those in the lower part of the SOM by natural stream samples. Subclusters in the middle position, contained both natural (19) and regulated (20) samples in nearly equal proportion. In addition, the SOM contained one subcluster with sites only from the regulated period and another with only natural sites. Differences between subclusters were attributed to differences in climate, with some differences profound. Warming of the local weather, which became most evident in the 1990s, may have resulted in changes in fish assemblages. This is shown in the SOM, in which samples from the 1980s with cold years dominate the bottom of the SOM, whereas those from the 1990s and later are at the top. Subclusters dominated by regulated or natural sites were not always significantly different when the number of species and diversity indices were considered. Clear differences between the regulated and natural samples involved qualitative characteristics and mainly concerned assemblage composition. They were also confirmed by significant IndVal values (indicator species) and neither mixed subcluster contained important species in their assemblages.     

开展对环境无害的煤炭革命保护全球环境

发展中国家正处于工业化起始和发展阶段,煤炭的开发和利用逐年增多,这将造成对环境的污染。因此,包括中国在内的发展中国家,面临着能源结构和能源利用方式一次新的战略变革,这种变革使资源消费型发展模式,转向资源节约模式。中国本着负责的态度,在发展经济的同时始终把环境保护作为一项基本国策。但限于发展中国家财力和技术条件有限,我们希望国际社会建立保障环境安全和发展的国际资金机制,包括以优惠或非商业性条件转让环境保护有益的技术和提供足够的、新的和额外的资金以推动新技术的应用。     

试论工程地质超前预报与施工安全

塌方是较常见的矿山事故,往往造成人员伤亡和设备损坏。为此,探索了一种适用于中长期和短期工程地质超前预报相结合的方法,来预报巷道施工过程中可能塌方的地段,并提出预防措施的具体方法。这种方法,在实践中取得了较好的效果。     

新型正渗透汲取液的试制及其处理浓盐水的应用

选取柠檬酸盐改良磁性纳米颗粒汲取液作为正渗透汲取液,研究其在浓盐水处理中的应用效果,采用热合成方法控制温度为30、60和90℃时制成了柠檬酸盐改良磁性纳米颗粒（MNP0、MNP1和MNP2）。对3种磁性纳米颗粒进行表征的结果显示,随反应温度的升高,分散性提高,同时温度升高,更有利于柠檬酸盐包覆到磁性纳米颗粒的表面。不同温度条件下合成的3种柠檬酸盐磁性纳米颗粒处理浓盐水测定水通量和反向盐通量研究表明,MNP2的水通量较MNP0和MNP1高,为23 L·（m2·h）-1,且水通量下降较稳定,反向盐通量较小。不同粒径的MNP2处理浓盐水研究结果表明,水通量随粒径的减小呈现增加趋势,粒径为3.5 nm时的渗透压和水通量最高且减压渗透（pressure relief osmosis,PRO）模式下水通量较正渗透（forward osmosis,FO）模式高。     

球磨热碱耦合法破解污泥-释放碳源及污泥减量化的效率

研究了球磨热碱耦合法破解污泥释放碳源的效率,进一步探索了直接以破解液代替外加碳源用于反硝化脱氮的可行性,并研究了该方法对污泥减量化的效果。结果表明,在水浴温度80 ℃,复合碱投加量为154 mg·g ⁻¹(以污泥VS干重计),反应24 h后,对于浓缩后含水率为93.8%的污泥,破解液中SCOD达到2.013×10⁴ mg·L⁻¹,COD达到4.725×10⁴ mg·L⁻¹。三维荧光光谱显示,污泥破解液中荧光性有机物质以易生物降解的色氨酸类和微生物代谢副产物类占据主导地位。污泥处理前后,TS由61.7 g۰L⁻¹下降至15.6 g۰L⁻¹,其中部分超细颗粒随上浊液回收利用,污泥减量化程度达到74.7%;VS由30.4 g۰L⁻¹下降到4.6 g۰L⁻¹,挥发性有机质的去除率达到84.7%。粒径分析结果表明,原始污泥中值粒径由预处理前28.1 μm降为12.6 μm,粒径显著减小,并产生2.5 μm左右的细颗粒悬浮于破解液。随后以破解污泥沉淀后的上浊液直接作为替代碳源,在模拟的反硝化实验中(外加硝酸钾作为氮源),反应器持续运行稳定后,NO₃⁻-N的去除率均高于97.0%。以上结果表明球磨热碱耦合法是一种非常高效污泥减量化方法,破解液可有效作为反硝化碳源使用,污泥资源化和减量化效果好,是一种非常有前途的污泥处理处置方法。     

DISPERSION MODEL FOR A STREAM WITH SEVERAL WASTE INPUTS AND WATER INTAKES1

An analytical solution is developed to predict the BOD and DO profiles in a stream having several outfalls of waste and intakes of water. The model also incorporates continuous addition and removal of BOD and DO along the stream. A steady state one dimensional dispersion model is used to describe the transport of BOD and DO in a stream. Changes in stream properties along the length are considered by dividing the stream into several segments and changing the parameters of the BOD and DO equations as needed in each segment. By applying continuity equations at the boundaries of these segments and equilibrium conditions at either ends of the infinitely long stream, the arbitrary constants in the solutions to the differential equations for BOD and DO can be determined. Some applications of the results in studying water pollution problems are illustrated.     

BIOGEOCIIEMISTRY OF AN OLD-GROWTH FORESTED WATERSHED,OLYMPIC NATIONAL PARK,WASHINGTON1

ABSTRACT: The biogeochemistry of a coastal old-growth forested watershed in Olympic National Park, Washington, was examined. Objectives were to determine: (1) concentrations of major cations and anions and dissolved organic C (DOC) in precipitation, throughfall, stemflow, soil solution and the stream; (2) nutrient input/output budgets; and (3) nutrient retention mechanisms in the watershed. Stemilow was more acidic (pH 4.0–4.5) than throughfall (pH 5.1) and precipitation (pH 5.3). Organic acids were important contributors to acidity in throughfall and stemflow and tree species influenced pH. Soil solution pH averaged 6.2 at 40 cm depth. Stream pH was higher (7.6). Sodium (54.0 μeq L-¹) and Cl (57.6 μeq L^?1) were the dominant ions in precipitation, reflecting the close proximity to the ocean. Throughfall and stemflow were generally enriched in cations, especially K. Cation concentrations in soil solutions were generally less than those in stemilow. Ion concentrations increased in the stream. Dominant ions were Ca (759.7 μeq L^?1), Na (174.4 μeq L^?1), HCO₃ (592.0 μeq L^?1), and SO₄ (331.5 μeq L^?1) with seasonal peaks in the fall. Bedrock weathering strongly influenced stream chemistry. Highest average NO₃ concentrations were in the stream (5.2 μeq L^?1) with seasonal peaks in the fall and lowest concentrations in the growing season. Nitrogen losses were similar to inputs; annual inputs were 4.8 kg/ha (not including fixation) and stream losses were 7.1 kg/ha. Despite the age and successional status of the forest, plant uptake is an important N retention mechanism in this watershed.     

钻井水溶开采地面沉降的机理分析与控制对策措施研究

本文通过对某矿钻井水溶开采的溶腔稳定性、覆岩稳定性和地表移动变形分析计算,探讨了该矿产生溶腔失稳和地面沉降的机理,并提出了控制溶腔失稳和地面沉降的对策措施,对钻井水溶开采矿山有一定的借鉴价值。     

考虑中间主应力对圆形巷道Hoek Brown准则解的影响

为了建立更加适用于深部巷道围岩塑性解分析的Hoek Brown准则,获得更加准确的巷道围岩塑性区范围及其支护变形量。通过将洛德参数表示的中间主应力带入Hoek Brown准则中,经过理论公式的推导,获得巷道围岩塑性区的应力和半径以及巷道周边位移的解析解。经算例分析,随着中间主应力的减小,塑性区范围也减小,当中间主应力趋近于第三主应力时,塑性区范围为最小;并且支护阻力和原岩应力对巷道塑性区范围也有一定影响;最后将计算的结果与Mohr-Coulomb准则对应的卡斯特纳解进行比较,发现文中建立的Hoek Brown强度准则更加适用于深部巷道塑性区分析。由此可知考虑中间主应力的Hoek Brown强度准则,更能全面分析巷道围岩塑性区的范围,获得更为准确的结果;在工程实践中,在易破坏的地段取地应力值时,应适当的增大中间主应力的取值,并且刚开挖巷道应及时支护,这样可有效的维护巷道围岩的稳定。