煤岩动力灾害的氡监测技术初探

矿井开采深度和强度的逐年增加,致使深部煤与瓦斯突出等煤岩动力灾害变得更为严重,迫切需要有既行之有效又安全可靠的方法来对其进行预测预报.煤岩体的破裂过程伴随能量耗散及放射性核素氡析出,因此,检测氡的变化可以作为一种对煤岩动力灾害的预测方法.先介绍了我国煤矿井下氡的水平,分析了破裂煤岩氡析出异常机理,研究了煤岩放射性核素赋存的影响因素,再利用自主设计的循环式破裂煤岩氡析出测定试验系统,初步研究了煤岩块试样破坏前后的氡析出变化.结果表明,煤岩块试样在破坏前后,氡浓度出现异常变化,破坏后较完整的煤样氡气放射增加50％以上,破坏后较完整的岩样氡气放射增加1倍以上.这表明氡检测技术在煤矿动力灾害探测中具有较好的应用前景.     

基于双层规划模型的城市固体废物管理系统优化研究

采用变权重组合模型和情景分析法,对北京市的城市固体废物(MSW)产量进行有效地预测.预测结果表明,北京市垃圾产量增幅不大但处理设施容量存在缺口.在科学预测的基础上,构建以温室气体(GHG)控制为上层目标,系统成本最小化为下层目标的双层规划模型(BLPMGMC).该模型的结果表明,焚烧和堆肥将是北京市MSW的主要处理方式;在3个规划时段内,GHG总排放量达到1.67×106t(以CO2当量计),填埋场的CH4和焚烧厂的N2O是GHG排放的主要贡献者;系统总成本达到7.0×109元,其中,65%的成本来自于焚烧厂和堆肥厂.4种模型结果的对比分析表明,双层规划能提供综合经济和环境因素的管理方案.     

高含固污泥水热预处理中碳、氮、磷、硫转化规律

以城市污水处理厂脱水污泥为对象,探讨其在165℃下经50 min水热预处理的碳、氮、磷、硫转化规律.结果表明,水热预处理可有效水解污泥中有机组分,VSS水解率达43.35%.碳、氮、磷、硫在水热预处理过程中表现出不同的转化规律,蛋白质和碳水化合物的水解率分别为54.36%和65.12%,溶解态有机物的主要组分为溶解态蛋白质(52.18%);不溶态有机氮的水解率54.23%,氨氮占溶解态凯氏氮的22.13%,水解液中的氮主要以有机氮形式存在;总磷水解率为30.52%,磷酸盐占溶解态总磷的79.84%,说明在水热预处理过程中聚磷酸盐在聚磷菌细胞破碎后极易被水解为磷酸盐;总硫水解率为50.03%,硫化物占溶解态总硫的0.50%,而有机硫很难水解为硫化物.通过水热预处理后物质转化及组分分析,旨在为高含固污泥有效处理提供一定的理论参考.     

两种空气自动监测系统的比较

国产长光程空气自动监测系统是中国自行研制的更为先进、更具自动化的系统，24h点式仪器是老式空气检测仪器，对这两种新、老仪器的比较可以看出在运行过程中的利弊。     

Dealing with uncertainty in qualitative models with a semi-quantitative approach based on simulations. Application to the Gironde estuarine food web (France)

In the context of ecosystem approach to fisheries, it is a critical issue to build management tools able to predict the possible trajectories of ecosystems under various human pressure or environmental variations, but also capable to point out influent and sensitive components.     

The short term agronomic impact of raising canal water levels in grassland areas: A case study in the Belgian polders

This study tested the hypothesis that raising canal water levels with 30 cm beyond the growing season in intensively managed lowland grassland (2.4-3.7 m above sea level) in Belgium decreases the agronomic value of pastures The study ran 3 years before and 3 years after the water elevation. Using five pairs of plots inside and outside the wetted perimeter, it was not possible to demonstrate significant impacts of the elevated water level on dry matter yield, forage quality, botanical composition, and penetration resistance of the top soil layer of the grassland. In an ex situ lysimeter experiment, simulating the effect of a water level in canals up to 50 cm beneath the surface of the pastures indicated a significant decrease of the penetration resistance of the top soil layer.Results are discussed and confronted with the difficulties of field research addressing the elevation of water levels.     

“一企一策”在风险精准防控中的应用实践

介绍了推行“一企一策”机制,实现HSSE风险精准防控的做法,探讨了风险细化识别方法、精准防控实施方法,分析了实施的效果,提出“一企一策”适用于全要素的风险精准防控和价值管理理念的落实。     

提升我国城市化水平的重要意义和政策调整

我国的城市化水平落后于工业化水平，已成为制约我国经济与社会发展的重要因素。提升我国城市化水平，从经济上讲，具有如下重要意义：（1）有利于化解有效需求不足矛盾。（2）有利于带动相关产业增长和主人口增加。（3）有利于促进我国产业结构优化，提高经济运行质量。（4）有利于资源的综合利用和耕地保护。（5）有利于缩小城乡差距。提升我国城市化水平是我国新世纪的战略任务，必须进行相关的政策调整与选择。     

Impacts of climate change on lakes and reservoirs dynamics and restoration policies

Meteorological-driven processes exert large and diverse impacts on lakes and their water quality; these impacts can be hydrologic, thermal, hydraulic, chemical, biochemical, or ecological. The impact of climate change on Lake Tahoe (California–Nevada) was investigated here as a case study of climate change effects on the physical processes occurring within lakes. The already published trends of meteorological variables were used to assess the effects of global warming on Lake Tahoe dynamics. Records from the period 1969–2002 show that Lake Tahoe has became warmer and more stable. A series of simulation years into the future (i.e., 2000–2040) was established using flows, loads, and meteorology data sets for the period 1994–2004. Results of 40-year simulations show that the lake continues to become warmer and more stable, and mixing is reduced. Possible changes in water quality because of global warming are discussed through inference, although these are not specifically simulated. Many existing problems may be exacerbated due to climate change, yet extreme uncertainty depends on the rate and magnitude of climate change. Therefore, shifts in water quality and quantity due to climate change should be integrated into contemporary planning and management in an adaptive manner, and the research and development of impact assessment methodology should focus on approaches that can handle extreme uncertainty. The general alternatives for lake management due to climate change are discussed. Depending on the specific case, further intensive research is suggested to restore lake water quality.     

Dynamic analysis of a one-prey multi-predator impulsive system with Ivlev-type functional

Considering the Ivlev-type functional response, we develop and analyze a class of one-prey multi-predator system with impulsive effect at different fixed times. Some sufficient conditions ensuring the prey to be extinct are obtained via the Floquent theory and small amplitude perturbation skill. Using the method of comparison involving multiple Laypunov functions, we derive some conditions for the permanence of the system. Numerical simulations of the impulsive system exhibit the rich complex dynamics for the key parameters, such as symmetry-breaking pitchfork bifurcation, periodic doubling bifurcation, chaos, periodic halving cascade and crisis.