中压配电网网架优化规划方法

为了提高中压电力网的规划水平,该文以最短路径和最小负荷矩法为基础,考虑物理约束、道路、支路电流和节点电压等约束条件,提出了确定主干线、连接负荷点方法和自动搜索交叉点（中间节点）以及选择导线截面的方法,给出了线路拉手前后节点和支路编号的方法,并且可以自动搜索相邻线路的联结点,实现相邻线路的手拉手连接,最终实现相邻2条自线路的自动布线。并且以农网的实际数据为例,进行计算、分析和比较,结果表明,该文提出的方法可以自动形成网架,确定网络中各支路的型号,保证相邻2条线路在拉手前后的支路电流、有功功率损耗率和节点电压均满足约束条件,是一种有效的网架优化规划方法,可以为配电网网架的规划提供必要的数据和技术支持。     

基于分布式水文模型的嘉陵江流域氮磷非点源污染负荷预测

为研究在大尺度流域上以降雨径流为载体的非点源污染,以基于土地利用的分布式水文模型(SLURP Hydrological model)为基础,提出氮磷负荷预测模型及未来气象参数和土地利用分布图的构建方法.就嘉陵江流域土地利用、畜禽养殖和农业人口未来变化产生的总氮与总磷的月负荷量进行模拟和预测分析.结果表明,预测年降雨径流...     

大气酸性污染物对树皮树叶pH值变化的影响

通过测定常见树种的树皮、树叶的ｐＨ值以及对应的大气污染状况,研究了大气中污染物的含量对树木ｐＨ值的影响。结果表明,大气中ＳＯ２污染对植物ｐＨ值影响最大。黄杨、柳树等树叶、树皮ｐＨ值与大气酸性污染物含量呈显著的负相关。按酸性大小排序为：燃性污染物〉燃料型工业区〉交通稠度区〉非燃料工业区〉生活居住区。     

吉林省几种常见生物质颗粒燃料的性能

对吉林省几种常见树种颗粒燃料的性能指标进行了测定分析.结果表明,7种颗粒燃料以玉米秸秆颗粒的灰分质量分数最大(11.90%),沙松去皮颗粒的灰分质量分数最低(0.37%);杨木颗粒的去灰分热值最大(20.896kJ/g),其次是椴桦混颗粒(20.885kJ/g),白桦去皮颗粒的去灰分热值大于白桦未去皮颗粒,木质颗粒大于秸秆颗粒.木质颗粒燃料以杂木颗粒燃料的轴向抗压性最强,其轴向载荷值为0.2355kN,其次为沙松去皮颗粒,其轴向载荷值为0.2149kN,白桦未去皮颗粒要强于去皮颗粒;白桦未去皮颗粒燃料的径向抗压性最强,其径向载荷值为0.6402kN,其次为杂木颗粒,其径向载荷值为0.6242kN,白桦未去皮颗粒要强于去皮颗粒.从抗压性角度分析宜选用杂木颗粒.杨木颗粒和杂木颗粒的质量损失率相对于其他4种颗粒较低,分别为0.1316%和0.1438%.椴桦混颗粒燃料的渗水率最大(10.235%),其次为白桦去皮颗粒(10.233%),白桦未去皮颗粒的抗渗水性要强于去皮颗粒.通过不同时间抗渗水性能测试,20h后,6种木质颗粒都呈完全剥落状,但杂木颗粒状态要稍好一些,外型仍呈颗粒状.不同颗粒燃料的去灰分热值、轴向载荷和抗渗水率具有显著差异(t检验,p<0.05).     

Utilization of municipal organic wastes in agriculture: where do we stand,where will we go?

Generation of organic waste is increasing worldwide and strategies for its environmentally sound use must be developed and optimized. Regulations in European countries and the USA differ largely with respect to requirements of organic waste quality and the quantities of pollutants which can be added to the soil. Research has shown beneficial effects regarding the improvement of soil fertility. Enrichment of total metals in soil was attributed to long‐term sludge application but the effect on bioavailability of metals must be further clarified. A number of organic pollutants, such as hydrophobic persistent organic contaminants and surfactants, are known to accumulate in organic wastes. However, the former interact strongly with organic matter in the sludge‐soil‐plant system and systemic plant uptake is generally assumed to be minimal. Surfactants may cause adverse environmental impacts when they enter sewage systems in high loads and accumulate in sludge. Surfactants and some of their metabolites are not readily biodegraded in non‐aerated environments. Due to their toxicity and estrogenic activity, of nonylphenol for example, more research is needed to optimize analytical techniques and to trace their behavior in soil. Some options to cope with the risks of huge amounts of organic waste and also some benefits are presented: (1) further limitation of standards for pollutants and reduced application rates; (2) improved treatment of sewage sludge to reduce the total and bioavailable portions of both heavy metals and organic pollutants; (3) adaptation of waste application rates to soil properties such as sorption capacity for pollutants; (4) harmonization of analytical protocols for organic contaminants, i.e. surfactants and metabolites, enabling a more thorough monitoring of the wastes which are to be applied onto soils.     

气相色谱-质谱联用（GC-MS）技术解析红树林油状污染物成分及来源

随着现代化工业以及城市发展步伐的不断加快,海洋生态环境保护意识的缺乏以及人为干扰等问题,产生了一些对红树林湿地的面积及生态环境的影响,如水体富营养化的破坏。本文采用酸催化法、碱催化法和BF₃催化法进行甲酯化方法筛选,选取最优甲酯化法对海南红树林湿地保护公园（海南澄迈）内8个采样地点的水体样品的有机溶剂提取物进行甲酯化衍生预处理,采用气相色谱-质谱联用（GC-MS）技术选择离子的检测方法进行分离鉴定和归一法分析,并用碳数组成参数和分布特征探索园区内水体油状污染物来源,提出改善园区内水体改善的合理建议,为红树林湿地生态环境保护提供科学依据。结果表明：海南红树林湿地保护公园内水体油状污染物主要成分为烷烃（占比超过70%）,其中正构烷烃呈现出以低碳数为主的分布特征,碳数分布范围在C₁₀~C₃₃,其主峰为nC₁₇且L/H分布范围为1.51~2.19,发现水体污染源主要来自浮游生物和藻类输入。     

农药草铵膦产污系数研究

产污系数的研究是第二次全国污染源普查的基础之一。本文选取了两家以格氏工艺生产草铵膦农药原药的企业进行采样和调查,基于废水实测法和废气物料衡算法进行个体产污系数与品种产污系数核算,分析了两家企业产污差异的影响因素。结果表明:企业A的个体产污系数为化学需氧量1.09×106g t-1、氨氮969g t-1、总氮2.10×103g t-1、总磷750g t-1、挥发性有机物1.59×103kg t-1;企业B的个体产污系数为化学需氧量2.34×106g t-1、氨氮53g t-1、总氮795g t-1、总磷124g t-1、挥发性有机物335 kg t-1;品种产污系数为化学需氧量1.73×106g t-1、氨氮499g t-1、总氮1.43×103g t-1、总磷429g t-1、挥发性有机物748kg t-1。通过对两家企业产污系数影响因素的深入分析,发现原辅料的使用与投用量、有机溶剂和设备的使用不同是导致产污水平差异的主要因素。     

生物炭去灰分对萘和1-萘酚的吸附动力学影响

为探究生物炭矿物组分对有机污染物吸附过程的影响机制，考察（非）极性有机污染物萘和1-萘酚在不同温度（300、400、500℃）下制得的小麦秸秆原始生物炭以及去灰分后生物炭上的吸附动力学。结果表明：拟二级和双室一级动力学模型能较精确地描述目标污染物的动力学吸附过程。去灰分处理增加生物炭芳香碳含量，增强其与萘和1-萘酚间的p-p和疏水作用；同时降低生物炭表面极性，特别是减少表面烷氧基官能团的分布，提高疏水碳吸附域（主要是芳香碳）的可达性，导致平衡吸附量（Q_e）增大。除灰后极性官能团在生物炭表面的暴露减少，促进萘分子向表面疏水吸附位点扩散，使得萘在生物炭上快吸附单元的吸附速率常数（k_fast）升高；而极性1-萘酚结构中的—OH能通过氢键与生物炭表面极性官能团或矿物含氧表面相互作用，对快吸附有重要贡献，去灰分削弱氢键，造成其k_fast下降。致密的芳香碳组分和纳米级孔隙结构主要对萘和1-萘酚在生物炭上的慢吸附起作用，去灰分提高生物炭芳香化程度和孔隙度，使慢吸附对总吸附的贡献（k_slow）增大；同时使得化合物分子较难扩散进入更致密的生物炭内部。另外表面积和孔隙度的增大延长吸附平衡时间，两种化合物的慢吸附速率常数（k_slow）均降低。研究表明，生物炭的矿物组分、化学组成和极性官能团的空间分布显著影响有机污染物的动力学吸附过程，从而影响生物炭在有机污染控制中的吸附性能。     

Leaching of dissolved and particulate phosphorus via preferential flow pathways in a forest soil: An approach using zero‐tension lysimeters

Phosphorus (P) fluxes from forest soils are not well understood. For temperate zone forests, there is some evidence from watershed studies that P export occurs mainly in preferential flow pathways during storm events after dry periods. Therefore, we tested the practical applicability of a sampling approach, which should allow for quantifying P concentrations and fluxes. We used zero‐tension lysimeters, which were installed beneath the topsoil and in the subsoil at plots in the Tharandt Forest (Saxony, East Germany). Two storm events after dry periods were simulated by means of experimental sprinkler irrigation. Preferential flow water collected with the zero‐tension lysimeters was analyzed for total P (TP), particulate P (PP), dissolved organic P (DOP) and dissolved inorganic P (DIP), and the respective P fluxes were calculated. The results indicate that the experimental approach is applicable to estimate fluxes of different P fractions in preferential flow. Measured data point toward a distinct flushing of P in the first hours of heavy rainfall events with PP fraction playing a dominant role. In general, P concentrations decreased quickly during the first 2 h of irrigation and then remained constant. Initial concentrations and cumulative fluxes were highest in the subsoil samplers. For a better understanding of underlying processes, further research with a special focus on the PP fraction is necessary.     

Effects of controlled drainage on N and P losses and N dynamics in a loamy sand with spring crops

The effects of controlled drainage on N and P losses from soil were examined in a 4-year field drainage experiment on a loamy sand in Southern Sweden. Of the three plots (0.2 ha each), one was drained by conventional subsurface drainage (CD), and two by controlled drainage (CWT1 and CWT2). The groundwater level in the CWT plots was naturally drained to at least 70 cm below the soil surface during the vegetation period between early spring and harvest but allowed to rise to 20 cm below the soil surface during the rest of the year. Measurements of precipitation, drain outflow, weir depths and air and soil temperatures were carried out hourly. Groundwater levels were measured and samples of drain outflow for analyses were collected twice a month. Mineral N contents in soil were measured three times a year and grain yields and N uptake in crops after harvest.