空气和废气中吡啶检测分析方法研究

研究了用5％乙醇-水溶液作为吸收液,直接进样1μ1,气相色谱仪分析,氢火焰检测器检测分析空气和废气中吡啶,检出限：0．01mg／L;吸收效率：98％;标准偏差：8％;曲线相关性：r=0．9993。均符合该物质便捷、准确、快速的检测要求。     

Economic feasibility of adapting crop enterprises to future climate change: a case study of flexible scheduling and irrigation for representative farms in Flathead Valley,Montana, USA

Future climate change directly impacts crop agriculture by altering temperature and precipitation regimes, crop yields, crop enterprise net returns, and net farm income. Most previous studies assess the potential impacts of agricultural adaptation to climate change on crop yields. This study attempts to evaluate the potential impacts of crop producers’ adaptation to future climate change on crop yield, crop enterprise net returns, and net farm income in Flathead Valley, Montana, USA. Crop enterprises refer to the combinations of inputs (e.g., land, labor, and capital) and field operations used to produce a crop. Two crop enterprise adaptations are evaluated: flexible scheduling of field operations; and crop irrigation. All crop yields are simulated using the Environmental Policy Integrated Climate (EPIC) model. Net farm income is assessed for small and large representative farms and two soils in the study area. Results show that average crop yields in the future period (2006–2050) without adaptation are between 7% and 48% lower than in the historical period (1960–2005). Flexible scheduling of the operations used in crop enterprises does not appear to be an economically efficient form of crop enterprise adaptation because it does not improve crop yields and crop enterprise net returns in the future period. With irrigation, crop yields are generally higher for all crop enterprises and crop enterprise net returns increase for the canola and alfalfa enterprises but decrease for all other assessed crop enterprises relative to no adaptation. Overall, average crop enterprise net return in the future period is 45% lower with than without irrigation. Net farm income decreases for both the large and small representative farms with both flexible scheduling and irrigation. Results indicate that flexible scheduling and irrigation adaptation are unlikely to reduce the potential adverse economic impacts of climate change on crop producers in Montana’s Flathead Valley.     

长径比对卧螺离心机内流场影响的数值模拟

研究用于污泥脱水的卧螺离心机的分离性能,并应用FIUENT软件建立卧螺离心机螺旋流道内污泥流体的两相湍流三维模型。主要研究不同转鼓长径比对卧螺离心机分离性能的影响,间接给出了不同长径比对卧螺离心机分离性能的影响关系图,并得到了该卧螺离心机最佳转鼓长径比的几何尺寸,为进一步研究离心机特性参数对其分离性能的影响和结构优化提供了理论依据。     

清河流域水生态维持功能评估

利用野外样点调查数据、遥感解译数据和多年降水监测数据,从生物多样性维持功能、生境维持功能和水资源支持功能3个方面对2011年清河流域水生态维持功能进行评估,为"十二五"期间水专项在清河流域开展水环境管理技术实施示范效果评估奠定基础。结果表明:2011年清河流域生物多样性维持功能和生境维持功能较好,而水资源支持功能较差。建议通过开展生态保护工程增加植被覆盖度,增强水资源支持功能和水土保持能力。     

有效微生物技术在城市环境治理领域中的应用

随着经济的快速发展,人口数量急剧增长,我国城市水污染及生活垃圾的安全处置问题日益严重,因此找到一种简单、经济的处理方法是目前迫切需要解决的问题。介绍了有效微生物的种群特点以及处理污水的机理,阐述了有效微生物对污水处理效果的影响因素,综述了有效微生物技术在污水处理、河湖富营养化治理、生活垃圾处置等方面的研究现状,并指出了该技术在城市环境治理领域的发展趋势和研究方向。     

Biodegradation of nicosulfuron by a novel Alcaligenes faecalis strain ZWS11

A bacterial strain ZWS11 was isolated from sulfonylurea herbicide-contaminated farmland soil and identified as a potential nicosulfuron-degrading bacterium. Based on morphological and physicochemical characterization of the bacterium and phylogenetic analysis of the 16S rRNA sequence, strain ZWS11 was identified as Alcaligenes faecalis. The effects of the initial concentration of nicosulfuron, inoculation volume, and medium pH on degradation of nicosulfuron were investigated. Strain ZWS11 could degrade 80.56% of the initial nicosulfuron supplemented at 500.0 mg/L under the conditions of pH 7.0, 180 r/min and 30°C after incubation for 6 days. Strain ZWS11 was also capable of degrading rimsulfuron, tribenuron-methyl and thifensulfuron-methyl. Four metabolites from biodegradation of nicosulfuron were identified, which were 2-aminosulfonyl-N, N-dimethylnicotinamide (M1), 4, 6-dihydroxypyrimidine (M2), 2-amino-4, 6-dimethoxypyrimidine (M3) and 2-(1-(4,6-dimethoxy-pyrimidin-2-yl)-ureido)-N,N-dimethyl-nicotinamide (M4). Among the metabolites detected, M2 was reported for the first time. Possible biodegradation pathways of nicosulfuron by strain ZWS11 were proposed. The degradation proceeded mainly via cleavage of the sulfonylurea bridge, O-dealkylation, and contraction of the sulfonylurea bridge by elimination of a sulfur dioxide group. The results provide valuable information for degradation of nicosulfuron in contaminated environments.     

某边坡地震工况下的稳定性数值模拟分析

地震是引起边坡失稳的重要因素之一,文章以怒江上游干流左岸一边坡为例,利用Flac3D软件对其在地震工况下的稳定性进行了数值模拟分析。通过对比得出:在天然工况下,边坡塑性区域分布范围较小且零星,剪应变增量和位移场分布均合理分布,边坡处于稳定状态;在地震工况下,塑性区域形成贯通面,剪应力增量集中分布在基岩与变形带分界面,并且位移大幅增加,此时边坡处于失稳破坏状态。文章对揭示边坡在地震作用下失稳机制提供有益参考。     

高压隔离开关温度在线监测系统开发与应用

针对高压隔离开关触头温度测量难度大、准确性不高且影响可靠供电问题,提出一种新的基于电场感应供能的隔离开关温度悬浮测量及无线传输方案,完成基于 ZigBee(基于 IEEE802.15.4 标准的低功耗局域网协议)无线射频技术的无线专网组网,研发了变电站温度在线监测系统。应用结果表明:高压隔离开关触头温度在线测量准确,数据传输实时性好,在线监测系统运行稳定。     

Understanding the Underwater Behaviour of Scuba Divers in Hong Kong

Diving-related activities may constitute a major threat to coral reefs. This study aimed to quantify the impact of diving in Hong Kong on hard corals and understand how socio-economic characteristics and experience level of divers influence diver-inflicted damage. We recorded and analysed the underwater behaviour of 81 recreational divers. On average, a diver was in contact with marine biota 14.7 times with about 40 % of contacts involved corals and 38 % were damaging contacts with corals or other biota in a single dive. The most harm-inflicting groups included inexperienced and camera-carrying divers. Although Hong Kong divers did not make many damaging contacts with corals, there is still an imminent need to determine the scale of damage from diving activities on the marine ecosystem given the rapid development of marine-based tourism and the limited coral-inhabited areas in Hong Kong where the marine environment is already under stress from anthropogenic activities.     

Opposite response of phosphorus sorption to pH and ionic strength: a comparative study in two different shallow lake sediments

Phosphorus (P) sediment sorption is regarded as the most important buffering process against P increases in overlying water. In this study, two shallow eutrophic sediments (Mei and Hua) with distinct compositions were selected to assess effects of pH (from 6 to 9) and ionic strength (IS) (0, 0.001, 0.01 and 0.1 M KCl) on P sorption. In Mei sediments, the P sorption decreased as pH increased (6.97–9.13), but it increased as IS increased over the pH range in question. These results could be attributed to the negatively charged surface of Mei sediments, as indicated by the salt titration curve, and the high cation exchange capacity (CEC). P sorption in Hua sediments was facilitated by a pH increase (6.12–7.49), but it was hindered by an IS increase. A reasonable explanation for this phenomenon is that calcium phosphate precipitates at high pHs and that Cl^? exchanges with P because the surface is weakly charged (small CEC). These results indicate that the sediment P sorption may have trends opposite to one another in relation to the salt change (e.g. drought and rainy season) in the lake water between the two sediments. These data provide additional support to explain P concentration variations in lakes.