Analysis of pollutant levels in central Hong Kong applying neural network method with particle swarm optimization

Air pollution has emerged as an imminent issue in modernsociety. Prediction of pollutant levels is an importantresearch topic in atmospheric environment today. For fulfillingsuch prediction, the use of neural network (NN), and inparticular the multi-layer perceptrons, has presented to be acost-effective technique superior to traditional statisticalmethods. But their training, usually with back-propagation (BP)algorithm or other gradient algorithms, is often with certaindrawbacks, such as: 1) very slow convergence, and 2) easilygetting stuck in a local minimum. In this paper, a newlydeveloped method, particle swarm optimization (PSO) model, isadopted to train perceptrons, to predict pollutant levels, andas a result, a PSO-based neural network approach is presented. The approach is demonstrated to be feasible and effective bypredicting some real air-quality problems.     

固定化微生物处理有机污染物的研究进展

综述了近年来固定化微生物技术用于有机污染物治理中的最新进展，这些有机污染物包括难降解有机污染物（酚类、芳香烃类等）及其它化合物（DMP、甲硫醇恶臭气体、制药废水等）。此外，对藻类固定化技术作了简介，并对固定化技术的应用前景及存在问题进行了评述。     

A Global Overview of Atmospheric Acid Deposition Fluxes

This paper presents a summary of globalacid deposition flux data taken from a globalassessment report on acid deposition prepared forUNEP/WMO (Whelpdale and Kaiser, 1996). There is a largevariation in the spacial coverage and reliability ofmonitoring around the world. Many more stationsmeasure wet deposition than collect appropriate datafor estimating dry deposition. The widespread regionswith highest precipitation concentrations anddeposition fluxes of sulphate and nitrate coincideclosely with the regions of highest density ofSO₂ and NO_x precursor emissions occurringprimarily in the mid-latitude, northern hemispherebelt where a large fraction of the worlds fossilfuels is consumed. Organic acids in precipitation makea minor contribution to acidity (<20%) inindustrial regions, but in the rest of the world theyare of same order, or even exceed, inorganic acids.Less is known about dry deposition, but it appears topredominate near strong emission sources with wetdeposition predominating farther downwind. The molarratio of the N/S contribution to acidic deposition isclose to 1.0 over large areas of Europe and NorthAmerica, but is highly variable elsewhere, beinghighest in equatorial regions due to biomass burningand lowest near smelters and other large sources of SO₂.     

高级氧化技术机理及在水处理中的应用进展

综述了近年来发展迅速的高级氧化技术，主要包括Fenton法、臭氧氧化法、湿式氧化技术、超临界水氧化法、纳米光催化氧化法电化学催化降解法及超声降解法等。介绍了各种高级氧化技术的基本原理及在废水处理中的应用进展，并对其特点进行了评述。     

在污染条件下生物的生态效应

主要就污染物对动物、植物及人体健康的危害，以及在污染条件下生物的适应与进化作一综述。     

Influence of new town development on the urban heat island - The case of the Bundang area

Five new towns have been developed around the Seoul metropolitan area since 1996. However, these new towns generate lots of traffic and related problems in the areas including those new towns and Seoul as a result of increases in population and a lack of ecological-self-sufficiency. Currently, construction of another new town is under deliberation, and what should be a major consider is the notion that the new town be located within a wide, green zone. Many studies have revealed that green space can play an important role in improving urban eco-meteorological capability and air quality. In order to analyze the urban heat island which will be created by the new urban development, and to investigate the local thermal environment and its negative effects caused by a change of land use type and urbanization, Landsat TM images were used for extraction of urban surface temperature according to changes of land use over the last 15 years. These data are analyzed together with digital land use and topographic information. As a study result, it was found the urban heat island of the study area from 198.5 to 1999 rapidly developed which showed a difference of mean temperature above 2.0. Before the Bundang new town construction the temperature of the residential area was the same as a forest, but during the new town construction in 1991 analysis revealed the creation of an urban heat island. The temperature of a forest whose size is over 50% of the investigation area was lowest, and thus the presence of a forest is believed to have a direct cooling effect on the urban environment and its surroundings. The mean temperature of the residential and commercial areas in the study was found to be 4.5 higher than the forest, and therefore this part of land use is believed to be the main factor causing the temperature increase of the urban heat island.     

活性污泥生长的控制

在污水处理过程中，针对不同的运行环境，我们选择适当的运行工艺和参数。通过控制菌胶团细菌和丝状菌平衡生长，或者是使固着型原生动物占优势，来获得良好的活性污泥，保证出水达标排放。     

南京雨花石

南京出产的雨花石为天赐瑰宝，按照矿物岩石学可分为11类，可从岩石质地、艺术、科学、历史四个方面评价其价值。雨花石作为砾石、卵石主要是由河流作用形成的，而组成雨花石的原岩的成因各异，火山作用是最为重要的成因方式。雨花石可从产品销售以及发展旅游事业等方面加以利用，搞好规划开发利用时要注意保护资源。     

废气污染控制高新技术的研究与应用

列举了大量的事实，重点介绍了几种高新技术在废气污染控制中的研究与应用，说明了向环保发展迟缓领挑战依赖于科学技术，而环保的发展又向科学技术提出了更高的要求。     

重力挡土墙地震反应研究评述

首先，对重力挡土墙的地震反应机理进行了探讨，在此基础上简要回顾了国内外抗震设计规范的演变进程；然后，对挡土墙地震反应的研究方法进行了细致评述，包括拟静力极限平衡分析法、简化条件解析法、极限位移法、地震土压力简化公式、集总参数法、整体有限元法、现场地震调查、离心机试验、振动台试验和原型观测实验等；最后，指出了需要解决的问题并提出了今后的研究方向。