端面齿形的切削加工与冷锻成形

对端面齿齿形的各种加工原理作了详细的介绍,分析了切削加工及冷锻成形工艺对端面齿齿形的影响.     

中美水源地管理体系的比较研究

以反映中美水源地管理水平的特大型城市上海、纽约为例，对两国水源地同管理体系中的政策法规，保护措施，土地规划使用，污染源控制等项目进行比较研究。分析中美水源地保护的技术水平，管理措施，经济手段等方面的差异，指出我国水源地管理工作在先进技术的应用。面源污染的控制，各方协调，公众参与，宣传教育，经济杠杆等方面均与国外存在一定差距。并对我国水源地的管理工作提出了建议。     

大气细菌粒子与飘尘粒子的关系

本研究用ANDERSEN生物粒子采样器和光散射气溶胶粒子计数器,在北京西单和丰台对大气细菌粒子与飘尘粒子的浓度和浓度分布及两者之间的关系进行了观测。结果表明,大气细菌粒子的日平均浓度为2.882个/l,浓度分布是从第6级至第1级逐级增大;飘尘粒子的平均浓度为149464个/l,浓度分布是从0.5～32μm依次减小:大气细菌粒子浓度与≥2.0μm的飘尘粒子有非常明显的正相关关系。     

大气质量标准技术经济评定的数学模型

本文从研究大气质量与改善大气环境的技术措施及经济投资三者之间的关系着手,建立一套数学模型为大气标准的评定提供一个实用的工具。并将此理论模型应用于北京市SO_2年平均浓度二级标准的评定工作,得出以0.08mg/m~3为宜的结论。 本文所提出的数学方法对其他环境要素的质量标准的评定及某些技术经济问题也有一定的参考意义。     

GIS支持下的交通噪声预测与规划系统

以地理信息系统（ＧＩＳ）为技术支撑，结合交通噪声预测模型，建立了交通噪声预测与规划系统ＴＮＰＰＳ，该系统充分利用ＧＩＳ对空气数据与属性数据进行编辑，管理，显示，查询的能力与分析建模优势，并注重用户与系统的交互，用户与系统交互以ＷＨＡＴ ＩＦ提问／解释方式进行。ＧＩＳ与环境模型相结合，为环境噪声调查，道路工程设计，建筑设计等提供了有效的交通噪声预测与规划工具。     

关于土壤环境容量的结构模型

本文从生态学观点出发,根据对土壤生态系统稳定性的认识,提出一种关于土壤环境容量的结构模型,为容量模型研究探索了一条新的道路。该模型的特点是考虑到污染物对系统中各组分的影响及组分之间的相互关系,从而使模型研究开始涉及容量问题的实质。本模型并把已有的关于土壤环境容量的等比级数模型作为一种特例包括在内。 本文还列举了在北京东南郊土壤系统实际研究中应用该模型的计算过程及所得的若干结果。     

Cause of PM2.5 pollution during the 2016-2017 heating season in Beijing, Tianjin, and Langfang, China

To investigate the cause of fine particulate matter (particles with an aerodynamic diameter less than 2.5 µm, PM_2.5) pollution in the heating season in the North China Plain (specifically Beijing, Tianjin, and Langfang), water-soluble ions and carbonaceous components in PM_2.5 were simultaneously measured by online instruments with 1-hr resolution, from November 15, 2016 to March 15, 2017. The results showed extreme severity of PM_2.5 pollution on a regional scale. Secondary inorganic ions (SNA, i.e., NO₃^?+SO₄²+ NH₄⁺) dominated the water-soluble ions, accounting for 30%-40% of PM_2.5, while the total carbon (TC, i.e., OC + EC) contributed to 26.5%-30.1% of PM_2.5 in the three cities. SNA were mainly responsible for the increasing PM_2.5 pollution compared with organic matter (OM). NO₃^? was the most abundant species among water-soluble ions, but SO₄^2- played a much more important role in driving the elevated PM_2.5 concentrations. The relative humidity (RH) and its precursor SO₂ were the key factors affecting the formation of sulfate. Homogeneous reactions dominated the formation of nitrate which was mainly limited by HNO₃ in ammonia-rich conditions. Secondary formation and regional transport from the heavily polluted region promoted the growth of PM_2.5 concentrations in the formation stage of PM_2.5 pollution in Beijing and Langfang. Regional transport or local emissions, along with secondary formation, made great contributions to the PM_2.5 pollution in the evolution stage of PM_2.5 pollution in Beijing and Langfang. The favourable meteorological conditions and regional transport from a relatively clean region both favored the diffusion of pollutants in all three cities.     

石油烃降解菌在高温高盐环境中的生理特性及应用潜力

分析了石油烃降解菌的生理特性及耐温、耐盐机制,介绍了国内外在高温高盐含油污水生物处理以及在高温高盐油藏的微生物采油方面应用石油烃降解菌方面的研究进展。国内外的研究结果表明,微生物在高温(地温120℃)、高矿化度(10×104mg／L)的油藏条件下,仍能保持较高的存活率,增油效果较好。     

Distribution of Chironomidae (Insecta: Diptera) in polluted rivers of the Juru River Basin, Penang, Malaysia

The influence of physical and chemical parameters on the abundance and diversity of chironomids was studied in six rivers with moderate to highly polluted water in the Juru River Basin. The rivers: Ceruk Tok Kun (CTKR) as reference site, and polluted rivers of Pasir (PR), Juru (JR), Permatang Rawa (PRR), Ara (AR) and Kilang Ubi (KUR) were sampled over a period of five months (November 2007–March 2008). Nine chirnomid species: Chironimus kiiensis, C. javanus, Polypedilum trigonus, Microchironomus sp., Dicrotendipes sp., Tanytarsus formosanus, Clinotanypus sp., Tanypus punctipennis and Fittkauimyia sp. were identified. Assessment of their relationships with several environmental parameters was performed using the canonical correspondence analysis (CCA). Tanytarsus formosanus was the most dominant in the relatively clean CTKR and moderately polluted JR with mean densities of 19.66 and 25.32 m?2, respectively while C. kiiensis was abundant in more polluted rivers. Tanytarsus formosanus, Dicrotendipes sp. and Microchironomus sp. were grouped under moderate to high water temperature, total organic matter (TOM), total suspended solids (TSS), velocity, pH, phosphates and sulphates. However, Tanypus punctipennis, Fittkauimyia sp., and Clinotanypus sp. were associated with high contents of river sediment such as TOM, Zn and Mn and water ammonium-N and nitrate-N and they were associated with higher dissolved oxygen (DO) content in the water. Chironomus kiiensis, C. javanus and P. trigonus showed positive relationships with TOM, ammonium-N and nitrate-N as well as trace metals of Zn, Cu and Mn. These three species could be considered as tolerant species since they have the ability to survive in extreme environmental conditions with low DO and high concentrations of pollutants. Based on the water parameter scores in all rivers, the highest diversity of chironomid larvae was reported in CTKR. With higher concentrations of organic and/or inorganic pollutants as reported in PPR, KUR and AR, the chironomid larval diversity decreased, and the abundance of tolerant species, mainly Chironomus spp., increased.     

电厂输煤系统配置静电和布袋除尘设备的比较分析

文章分析了电厂输煤系统产生粉尘污染的原因及其特性,提出了选择配置除尘器的基本原则,是在保证“两头不冒尘”的前提下,做到“室内外达标”。对输煤系统常用的布袋、静电两种除尘配置方式以及设备布置方式进行了比较分析,建议应综合比较系统的初投资、运行费用以及运行率,即系统寿命期成本来选择除尘设备,着重考虑选择长期运行维护工作量低和运行费用低的设备。建议优先采用尘源就地控制以及“干式除尘一于尘回收”的方式,列举了2×300MW机组输煤系统配套布袋除尘器和电除尘器技术参数与经济指标比较表,得出采用静电除尘方式的综合性价比优于布袋除尘方式的结论。