曝气对生物促生剂修复城市黑臭河道水体的影响

在实验室条件下研究了曝气对生物促生剂修复城市黑臭河道水体效果的影响，并通过控制曝气时间及强度考察处理效果以确定曝气方式和曝气量。结果表明：在生物促生剂修复城市河道黑臭水体过程中使用曝气协同作用可大大增强生物促生剂的修复作用，加快修复速度。使用间歇曝气协同生物促生剂作用时效果与连续曝气相近，且可以降低运行成本。实验60d后，上覆水COD、NH3-N和TP去除率分别达46．8％、98．7％和73．3％，上覆水pH由7．61提高至7．92；底泥削减达5．49cm，底泥有机质削减率达10．5％。     

毛乌素沙漠东部边缘中β尺度暴雨和冰雹综合分析

利用多普勒雷达资料、Micaps系统提供的常规观测资料和物理量场,对2006年9月20日发生在毛乌素沙漠东部边缘的一次强对流天气过程进行了分析。结果表明:冰雹和暴雨是由两块呈块状的中β尺度强对流单体造成的;地面能量比中α尺度"Ω"系统的生成,为能量的积聚和集中释放提供了有利条件;地面能量比中β尺度能量比低值舌的生成,为强对流天气的发生提供了抬升触发机制;冰雹和暴雨发生前,涡度场和散度场的耦合、影响雹暴区次级环流的形成,为雹暴的发生维持提供了动力机制;850 hPa等压面上湿正压场和湿斜压场的配合、以及湿位涡的三维空间结构,对雹暴的发生及落区有指示意义;在多普勒雷达径向速度场上,雹暴运动的前方对流层低层有中气旋生成,雹暴运动的后方对流层低层有中反气旋生成,而对流层中高层有辐散生成,且超级单体特征明显。     

Pt and Pd in sediments from the Pearl River Estuary,South China: background levels,distribution, and source

Purpose  

This study assessed the concentrations of platinum (Pt) and palladium (Pd) in surface sediments and sedimentary cores collected from the Pearl River Estuary with a view of evaluating the distribution, background levels, possible sources, and contamination level of anthropogenic Pt and Pd.     

A Comparison Study of Wheat Gluten Composites Filled with Dialdehyde Starch and Native Starch

Environmentally friendly green composites were prepared by blending Wheat gluten (WG) as matrix, dialdehyde starch (DAS) as filler and glycerol as plasticizer followed by compression molding of the mixture at 110 °C. The properties of the WG/DAS composite are compared with those of the WG/native wheat starch (NWS) composites. While tensile strength and strain at break decrease with increasing NWS content in the WG/NWS composites, a small content of DAS could improve tensile strength and strain at break simultaneously in the WG/DAS composites. The WG/DAS composites exhibit reduced moisture absorption in comparison with the WG/NEW composites. Formation of chemical bonding between DAS and WG is beneficial for the dispersion of DAS in the WG matrix and WG/DAS composites exhibit improved mechanical properties and reduced moisture absorption over the WG/NWS composites.     

Seasonal variation of mercury concentrations in organisms of the Cilician Basin

Total mercury concentrations in organisms typical of those found in the Cilician Basin of the northeastern Mediterranean have been measured from 1977 to the present. These concentrations show seasonal variations. Shrimp shows an approximately constant concentration of mercury which might testify to the regulation capacity of shrimp for mercury. Crab, and particular fish, show a seasonal variation which may be correlated with the local application of mercury fungicide, rainfall, and the physiology of the organisms. The rapidity with which mercury applied to the land causes increased concentrations in fish is noteworthy.     

内循环厌氧反应器多相流流场的三维数值分析简

利用数值模拟的方法，引入欧拉双流体多相流模型及标准k-ε紊流模型，模拟计算内循环厌氧反应器的三相流三维流场，并通过改变污泥颗粒密度及进水流量，针对固相流速及固含率的变化情况，分析条件的改变对流场的影响。研究结果表明，应用数值模拟方法可以获得内循环厌氧反应器内的流场特征；污泥颗粒密度及进水流量的改变对于反应器内污泥颗粒的流速及分布的均匀性有较为明显的影响。模拟结果对反应器的应用及优化设计具有一定的参考价值。     

巴颜喀拉山高寒草地及其退化的遥感研究─—以巴颜喀拉山达日县段为例

本文应用遥感技术，探讨了巴颜喀拉山北坡－青海省达日县段高寒草地资源及其退化高山草甸草地的成因、分布和判断标志，将研究区划分为5个草地类型和3个退化草地型，重点分析了高山草甸草地退化的主要原因和影象特征．     

粉末状和颗粒状有机膨润土对克百威的吸附

用十六烷基三甲基溴化铵(CTMAB)和十二烷基苯磺酸钠(SDBS)制得粉末状CTMAB阳离子有机膨润土(简称CTMAB-膨润土)和CTMAB-SDBS阴阳离子有机膨润土(简称CTMAB-SDBS-膨润土),并利用聚乙烯醇(PVA)包埋固定化技术将2种粉末状有机膨润土制成颗粒状有机膨润土,研究了粉末状与颗粒状有机膨润土对水中克百威的吸附性能.结果表明:粉末状CTMAB-膨润土和CTMAB-SDBS-膨润土对克百威的吸附效果较好,最终去除率分别为90.9％和92.5％,颗粒状CTMAB-膨润土和CTMAB-SDBS-膨润土对克百威的最终去除率分别为55.5％和60.3％；有机膨润土对克百威的吸附等温线符合Freundlich方程；颗粒状有机膨润土吸附克百威最多可重复利用6次.     

Resource use efficiency and economic losses: implications for sustainable rice production in Vietnam

The study aimed to estimate resource use efficiency and economic losses by using stochastic frontier analysis. The data set were collected in An Giang Province of Vietnam through personal interviews with 199 rice farmers. The results revealed that returns to scale are decreasing. Rice farmers had high levels of output-oriented and input-oriented technical efficiency with the means of 91.92 and 85.39 %, respectively. The mean environmental efficiency was 82.03 %. The mean efficiency of normal inputs was 61.20 %. Among the bad inputs, pesticide and energy were the least efficient ones with the mean values of 51.39 and 45.53 %, respectively, indicating serious overuses of these inputs. As regards normal inputs, capital had the lowest efficiency score at 21.08 %, followed by seed quantity at 26.4 %. Further, the total economic losses were estimated at 8261 thousand VND (380 USD) per hectare, which is equal to the sales of about 1600 kg of rice per hectare or the efforts to increase by 20 % of output level. This study suggests that rice farmers need to contract inputs, particularly environmentally detrimental inputs to improve profits. To improve the productive efficiency, the use of ecological engineering, collective pump and cultivation of three rice crops per year are possible options.