太湖梅粱湾水体中阿特拉津的毛细管气相色谱法测定

固相萃取（SPE）技术结合毛细管气相色谱（GC-μECD），测定了饮用水源地太湖梅粱湾水体中内分泌干扰物阿特拉津的含量，并用GC-MS进一步验证了分析结果。检测下限为10ng／L，方法回收率为75．58％～97．79％，RSD为0．38％～4．50％，在10ng／L-3640μg／L保持线性，其线性相关系数为0．9994。太湖梅梁湾水体中阿特拉津质量浓度在21．3～613．9ng／L，污染来源可能为太湖周围的农作区。     

Mechanism on minimization of excess sludge in oxic-settlinganaerobic (OSA) process

The oxic-settling-anaerobic (OSA) process is a promising wastewater treatment technique for efficiently reducing sludge production and improving the stability of process operation. In this paper, the possible factors of sludge reduction such as sludge decay, uncoupled metabolism, and anaerobic oxidation with low sludge production were discussed in the OSA process. It has been confirmed that sludge decay is the decisive cause in the OSA process, accounting for 66.7% of sludge production reduction. Sludge decay includes hydrolysis and acidogenesis of dead microorganisms and particle organic carbon adsorbed in sludge floc and endogenous metabolism. By batch experiments, it has been proven that there is energetic uncoupling in the OSA system since microorganisms were exposed to alternative anaerobic and aerobic environment. It accounts for about 7.5% of sludge production reduction. Soluble chemical oxygen demand (SCOD) released from the anaerobic sludge tank in the OSA process was used as the substrate for cryptic growth. The substrate was used for anoxic denitrifying, anaerobic phosphorus release, sulfate reduction, and methane production. These anaerobic reactions in the sludge anaerobic tank have lower sludge production than in the aerobic oxidation when equivalent SCOD is consumed, which may lead to approximately 23% of sludge reduction in the OSA process. It has been concluded that multiple causes resulted in the minimization of excess sludge in the OSA system. The microbial community structure and diversity of sludge samples from the CAS (conventional activated sludge) and OSA systems were investigated by 16 SrDNA PCR-DG-DGGE (polymerase chain reaction-double gradient-denaturing gradient gel electrophoresis). DGGE profile and cluster analysis showed more abundant species in the OSA system contrasting to microbial communities in the CAS system.     

012Al在螺母冲头模具上的应用

正确选用模具材料,对提高模具工作寿命至关重要。此文把012Al这种具有高强韧性的新钢种应用于螺母冲头,具有其推广价值。     

Real-time numerical simulations and experimental research for the propagation characteristics of shock waves and gas flow during coal and gas outburst

When coal and gas outburst occurs, high-speed gas flow and air shock wave with high kinetic energy could be created. In this paper, the formation process of outburst shock waves and gas flow has been analyzed firstly. Afterwards, the numerical simulation models of the roadways with right-angled intersection have been established, by which real-time simulation of the propagation of outburst gas flow and the process of gas transport has been conducted. Gas pressure, gas velocity and gas concentration can be simulated and shown. From analyzing the simulation results, qualitative and quantitative conclusions that the characteristics and patterns of the propagation and attenuation of outburst shock waves and gas flow can be arrived at. Finally, experimental models have been carried out to investigate the outburst shock waves and gas flow at the roadways with the similar shapes as the simulated ones. The results indicate that when shock wave and gas flow passes the intersection, most of the shock wave and gas flow will flow into the roadway of section opposite the intersection, and a little of it would flow into the roadway below the intersection. And turbulence will appear, shock wave reflects and diffracts at branches with more influence on the roadway below the intersection.     

Mechanism on minimization of excess sludge in oxic-settling-anaerobic (OSA) process

The oxic-settling-anaerobic (OSA) process is a promising wastewater treatment technique for efficiently reducing sludge production and improving the stability of process operation. In this paper, the possible factors of sludge reduction such as sludge decay, uncoupled metabolism, and anaerobic oxidation with low sludge production were discussed in the OSA process. It has been confirmed that sludge decay is the decisive cause in the OSA process, accounting for 66.7% of sludge production reduction. Sludge decay includes hydrolysis and acidogenesis of dead microorganisms and particle organic carbon adsorbed in sludge floc and endogenous metabolism. By batch experiments, it has been proven that there is energetic uncoupling in the OSA system since microorganisms were exposed to alternative anaerobic and aerobic environment. It accounts for about 7.5% of sludge production reduction. Soluble chemical oxygen demand (SCOD) released from the anaerobic sludge tank in the OSA process was used as the substrate for cryptic growth. The substrate was used for anoxic denitrifying, anaerobic phosphorus release, sulfate reduction, and methane production. These anaerobic reactions in the sludge anaerobic tank have lower sludge production than in the aerobic oxidation when equivalent SCOD is consumed, which may lead to approximately 23% of sludge reduction in the OSA process. It has been concluded that multiple causes resulted in the minimization of excess sludge in the OSA system. The microbial community structure and diversity of sludge samples from the CAS (conventional activated sludge) and OSA systems were investigated by 16 SrDNA PCR-DG-DGGE (polymerase chain reaction-double gradient-denaturing gradient gel electrophoresis). DGGE profile and cluster analysis showed more abundant species in the OSA system contrasting to microbial communities in the CAS system.     

Exploring the nexus between energy consumption,income inequality and poverty,economic growth,and carbon dioxide emission: evidence from two step system generalized method of moments

Environmental Science and Pollution Research - The concern of environmental degradation, poverty, and income inequality remains a priority in achieving sustainable development goals. Countries are...     

甲黄隆,氯黄隆,苄嘧黄隆及其降解产物对蛋白核小球藻生长的效应

本文研究了甲黄隆、氯黄隆、苄嘧黄隆及其降解产物对蛋白核小球藻（Chlorellapyrenoidosa）的96h生长抑制急性毒性和化合物氮的生物可获得性。急性毒性试验表明:黄隆的毒性比其降解产物取代磺胺和氮杂环化合物大得多（EC_(50)相差2—3个数量级）,降解产物取代磺胺、均三嗪、取代嘧啶存在明显的低浓度促进生长现象,氮的生物可获得性试验表明:小球藻能有效利用低浓度取代磺胺、均三嗪、取代嘧啶化合物中的氮促进生长,促进程度:氯磺胺>苄磺胺≈二甲氧基嘧啶>甲磺胺>均三嗪。     

西宁市主城区大气环境质量变化分析及对策研究

通过对西宁市主城区环境空气中主要污染因子二氧化硫、二氧化氮、总悬浮颗粒物近年来的变化原因进行了分析,提出了污染控制对策和措施。     

Levels and distribution of polybrominated diphenyl ethers (PBDEs) in the freshwater environment surrounding a PBDE manufacturing plant in China

Polybrominated diphenyl ethers (PBDEs) were determined in muscle, liver and eggs of freshwater fishes and surface sediments from the Nongkang River in Jinhu, Jiangsu Province, China. The present study is the first to report PBDE concentrations in the freshwater environment surrounding a PBDE manufacturing plant in China. The concentrations of 13 PBDE congeners in muscle, liver and eggs of freshwater fishes ranged from <LOD to 130, <LOD to 252 and <LOD to 33.3 ng/g lipid wt, respectively, while the concentrations of 13 PBDE congeners in surface sediments from sewage outfall, upstream and downstream of the river were 52, 9.2, 7.1 ng/g organic carbon wt, respectively. Contamination by PBDEs in this area was not serious when compared with other regions of the world. A relatively high proportion of BDE-183 was found, consistent with the octa-BDE technical mixtures from the manufacturing plant by the side of the river.     

γ辐照降解沉积物中六氯苯(HCB)的研究

研究了γ辐照法对不同河流湖泊沉积物中六氯苯(HCB)的降解效果,以及不同河流湖泊沉积物、HCB浓度、添加物、pH和容器内径对HCB辐照降解的影响,并对其降解动力学进行了探讨.结果表明,γ辐照法对南京玄武湖沉积物HCB模拟样品中HCB的降解率要高于长江南京上新河段和南京前湖沉积物HCB模拟样品;辐照下HCB质量浓度为10 mg/kg的长江南京上新河段沉积物HCB模拟样品的HCB降解率最高;添加H2O2能提高HCB的降解率,添加NaNO3和异丙醇降低了HCB的降解率;添加NaNO3的HCB降解率要高于添加异丙醇;pH越高HCB的降解率越大;容器内径对γ辐照降解容器中HCB的效果有较大影响,在其他实验条件一致下采用γ辐照降解HCB时,应尽量减小容器内径.