空气质量自动监测校准系统中存在的问题及解决办法

针对目前国内环境空气质量自动监测(干法)校准系统中存在的一些问题,提出相应的解决办法。     

Small towns in the united states: a perspective

Small towns are an important part of the rural settlement fabric in the United States, but there is very little substantive research into their capacity to survive or their intrinsic importance. However, recently there has been increasing interest shown by social scientists in these problems. This paper looks at features of this research from the point of view of the population and economic structure of small towns. It concludes by arguing that the problems of small towns are not indigenous to the towns, and calls for a comprehensive national urban policy.     

Housing in the new cities of Egypt

The New Cities of Egypt represent a major effort to redistribute investment and population away from Cairo and the Delta in a brave attempt to use desert land. Through a study of three cities under construction, the reliance on government‐built walk‐up flats for housing provision is discussed and its relevance for later phases questioned. In conclusion, the efficacy of the New Cities as counter‐attractions is doubted in the absence of effective controls on the growth of Cairo.     

高压喷射技术加固地基的工程实践

概述了在辽宁大洼县田庄台抽水站地基处理工程中采用高压喷射注浆技术的实践经验，并介绍了从工程勘察、方案选择、设计、施工和检测的全过程。此项技术，经过长期沉降观测取得了良好的加固成果。     

Experimental assessment of sensory modalities of coral-reef fish larvae in the recognition of their settlement habitat

One of the great mysteries of coral-reef fish ecology is how larvae locate the relatively rare patches of coral-reef habitat on which they settle. The present study aimed to estimate, by experiments in aquaria, the sensory modalities of coral-reef fish larvae for senses used in searching for their species settlement habitat. Larval recognition of settlement habitat can be based on the detection of conspecifics and/or of characteristics of coral habitat using visual, chemical and mechanical cues. For this study, larvae were captured with crest nets and were then introduced into experimental tanks that allowed testing of each type of cue separately (visual, chemical or mechanical cues). Among the 18 species studied, 13 chose their settlement habitat due to the presence of conspecifics and not based on the characteristics of coral habitat, and 5 species did not move toward their settlement habitat (e.g. Scorpaenodes parvipinnis, Apogon novemfasciatus). Among the different sensory cues tested, two species used the three types of cues (Parupeneus barberinus and Ctenochaetus striatus: visual, chemical and mechanical cues), six used two types (e.g. Myripristis pralinia: visual and chemical cues; Naso unicornis: visual and mechanical cues), and five used one type (e.g. Chrysiptera leucopoma: visual cues; Pomacentrus pavo: chemical cues). These results demonstrate that many coral-reef fish larvae could in practice use sensory cues for effective habitat selection at settlement, and have the ability to discriminate species-specific sensory cues.Communicated by J. Krause     

工业固废填埋场边坡防渗层环境安全分析

考虑了固废沉降的力学作用及坡角平台的影响机理,建立了尾矿渣、防渗膜及垫层相互作用的力学简化模型,应用平衡微分方程,结合边界条件,得到了防渗膜拉应力与位移的解析解及膜内最大拉力计算公式。最后,结合工程设计分析研究了重要参数对膜完整性的影响,并提出了相关解决机制。从力学机理上指导填埋场边坡防渗设计,具有很高的工程实际应用价值。     

胞外聚合物对活性污泥沉降和絮凝性能的影响研究

胞外聚合物 (EPS)对污泥沉降和絮凝性能具有重要影响 ,它由松散附着 (LB)和紧密粘附 (TB)的两部分组成。笔者考察了不同运行方式和不同泥龄培养的污泥LB和TB的含量及其成分对污泥沉降和絮凝性能的影响 ,研究结果表明 :虽然LB只占总EPS的 0 .6 %～ 13.5 % ,但它对污泥的沉降和絮凝性能起着决定作用 ,LB含量越多 ,污泥的沉降和絮凝性能越差 ;而TB的影响很小。因此 ,选择合适的运行方式 ,延长污泥泥龄 ,可减少LB含量 ,有利于活性污泥工艺运行安全、稳定、高效。     

大型垃圾填埋场表面沉降研究

研究了在上海市老港垃圾填埋场１７号填埋单元建造的２０００ｍ＾２小型卫生填埋场及表面沉降规律，结果表明，表面沉降与拉圾的压实程度有关，在填埋过程中，垃圾被充分压实后，学降就相对较小，在所监测的２．５年时间内，最大螺旋沉降大于１ｍ是垃圾填埋初始高度（４ｍ）的２５％，根据垃圾表面沉降的预测结果，讨论了老港垃圾填埋场的利用途径和可能性。     

Building consensus on divisive issues: a case study of the Yukon wolf management team

This article presents a case study of a successful effort to reach agreement on one of the most intractable environmental issues of our time: wolf management. This case is unusual in several ways. In this case, the members of the negotiating team were ordinary citizens rather than leaders of organized groups. This team was given an unusually high level of authority to write the plan as they saw fit; the agency pledged to implement “whatever they came up with.” The agency convened the process, but agency personnel were not members of the team and attended only when they were invited. The team members were able to reach agreement on this tough issue even though polar opposites were at the table—one who felt that wolves are a “spiritual essence” and another who felt that, as he put it, “wolves, coyotes, and cockroaches have a lot in common”. They produced a detailed plan that addressed all the issues in just 5 months. Another unusual aspect of this effort is that the final agreement does not list the team members. They explained that they wanted their plan to “stand alone” and be judged based on what it said, not on who was involved.However, just after their agreement was completed, a new, pro-wolf control government was elected that refused to endorse the plan. While the government gave various reasons for not ratifying the plan, more and more diverse interest groups came out in support for both the plan and the process that created it. Eventually, overwhelming public support forced the government to sign and implement the plan as written. This demonstrates that, while it is important for a team to seek the sanction of decision-makers, it is perhaps even more important for the general public to see the effort and the final agreement as fair. Strong support from a broad spectrum of the public can help win the necessary political support.In addition to discussing the unorthodox aspects of this consensus-building effort, this article also attempts to give the reader a front row seat to this process by using the informants' own words—words rich in detail, brimming with color and spoken straight from the heart. Certainly their experience dispels any notion that such efforts are simply a matter of following a recipe. During the process, members of the negotiating team experienced the entire gamut of emotions—anger, defeat, humor and, finally, a genuine sense of pride. As team member Patty Denison put it, “We showed that a random group of people could work together and do something truly monumental.”     

Long-Term Monitoring and Prediction for Settlement and Composition of Refuse in Shanghai Laogang Municipal Landfill

Parameters about composition of refuse such as mass percentage of biodegradable matter, volatile solid, organic carbon, cellulose, total sugar, and settlement were monitored and analyzed in a large-scale experimental unit. The empirical formulas between composition and refuse age were established in terms of the data obtained from the experimental unit and verified by comparing with the corresponding parameters of refuse in the closed landfill units from 1991 until 1994 in the Shanghai Laogang Municipal Landfill. Furthermore, the long-term prediction for the composition of refuse was made, and it was predicted that the half-life is 7 to 11 years for biodegradable matter, 9 to 12 years for organic carbon or volatile solid, 7 to 16 years for cellulose, and 4 to 6 years for total sugar. In addition, a mathematical model, based on the mechanism of refuse biodegradation in the landfill, was developed to simulate the relationship between the settlement and the refuse age and manifests the secondary settlement potential. The mathematical model was proved not only to be reliable but also should be accurate for predicting the settlement of the landfill. The secondary settlement, which mainly results from the slow and gradual biodegradation of refuse, is linear with respect to the exponent of refuse age. Finally, according to the settlement model and empirical biodegradation formulas, it may be predicted that, 79.4% of biodegradable matter, 92.9% of total sugar, 72.7% of volatile solid and organic carbon, and 73.1% of cellulose will be biodegraded and that 79% of the maximum secondary settlement potential will occur before the Shanghai Laogang Municipal Landfill is in a high stabilization situation, i.e., approximately 21 years after final closure.