北京市人口老龄化的时空变化特征

人口老龄化现已成为当今主要的人口问题之一,并引起越来越多的关注,人口老龄化进程与老年人口空间分布特征研究是未来人口问题研究的一个重要分支.本文基于ESDA全局和局部空间自相关分析,利用北京市第四次和第五次人口普查数据以及1995和2005年1％人口抽样调查数据,对北京市县域尺度老龄人口分布总体和局部空间差异的变化趋势、特征进行了初步探索.结果表明,北京市老龄人口空间分布各区县差异较大,且呈现出明显的圈层结构特征,中心四城区老龄人口比重较高,近郊区老龄人口比重较全市平均水平低,远郊区老年人口比重又有所回升;同时,北京地区老年人口各区县的空间分布差异随着时间的推移而不断扩大,中心老城区呈现不断增强的集聚趋势,而远郊区的老年人口扩散效应明显大于集聚效应.     

吉林省“十二五”环保政策措施研究

十二五期间,吉林省将处在经济高速发展时期,完善环境保护政策措施,是有效实施十二五环保规划的关键。通过全省环境保护政策措施的回顾,科学预测新时期环境保护工作形势,研究全省十二五时期环境保护法规体系、协调机制、经济政策、环保投入、科技创新等方面的对策措施。     

互花米草在上海崇明东滩的入侵历史、分布现状和扩张趋势的预测

近20余a来,互花米草在我国沿海及河口滩涂快速扩散,已成为我国海岸盐沼中最重要的入侵植物。上海崇明东滩是我国长江口的国际重要湿地,目前受到了互花米草入侵的严重威胁。自1995年在崇明东滩首次发现互花米草以来,互花米草的分布面积已超过1 600 hm2。总结了近几年在崇明东滩进行的互花米草相关研究,旨在对互花米草的控制与管理提供科学依据。目前互花米草主要分布在崇明东滩的东部及北部,决定其入侵动态与分布的主要因素在于：（1）互花米草对沿海滩涂环境具有良好适应与耐受能力;（2）人为引种大大加快了互花米草的扩张速度;（3）崇明东滩湿地的水分盐度条件特征导致互花米草主要分布在崇明东滩的东部与北部。根据互花米草的生理学特征和长江口地区的水文特点可以推断：互花米草在东滩东部和北部将继续扩张,但目前尚难入侵东滩南部区域,而人类活动可能加剧互花米草入侵。根据互花米草的入侵现状和趋势,必须尽快采取多种途径对互花米草进行控制和管理     

低温选择性催化还原脱除NOx的催化剂的研究进展

选择性催化还原(SCR)法是目前世界上应用较为成熟的烟气脱硝技术之一,由于传统的适用催化剂的起活温度偏高,因此开发低温高效、性能稳定的催化剂已成为该技术成功运用的关键.分析了SCR法的脱硝原理,对目前广泛研究的低温SCR催化剂的分类及其运用进行了综述,提出了研究中尚需解决的问题,最后展望了未来的研究方向.     

嗜麦芽窄食单胞菌对镉的吸附

利用从重金属镉污染地分离并纯化得到的1株嗜麦芽窄食单胞菌(Stenotrophomonas maltophilia)作为吸附剂,考察了镉初始浓度、菌浓度、吸附时间、温度及pH对镉吸附效果的影响.结果表明,在镉初始质量浓度为1.0 mg/L、30℃、pH为6～7条件下,菌质量浓度为2.0 g/L时,吸附120 min对镉...     

Spatial distribution of organochlorine contaminants in soil, sediment, and fish in Bikini and Enewetak Atolls of the Marshall Islands, Pacific Ocean

Several nuclear tests were performed at Enewetak and Bikini Atolls in the Marshall Islands between 1946 and 1958. The events at Bikini Atoll involved several ships that were tested for durability during nuclear explosions, and 24 vessels now rest on the bottom of the Bikini lagoon. Nine soil samples were collected from different areas on the two islands of the atoll, and eighteen sediment, nine fish, and one lobster were collected in the vicinity of the sunken ships. Organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polychlorinated terphenyls (PCTs) in these samples were analyzed using gas chromatography/ion trap mass spectrometry (GC/ITMS). The average recoveries ranged from 78% to 104% for the different PCB congeners. The limits of detection (LOD) for PCBs, PCTs, DDE, DDT, and dieldrin ranged 10-50 pg g⁻¹. Some fish from Enewetak contained PCBs at a concentration range of 37-137 ng g⁻¹, dry weight (dw), and most of the soils from Enewetak showed evidence of PCBs (22-392 ng g⁻¹ dw). Most of the Bikini lagoon sediment samples contained PCBs, and the highest was the one collected from around the Saratoga, an aircraft carrier (1555 ng g⁻¹ dw). Some of the fish samples, most of the soil samples, and only one of the sediment samples contained 2,2-bis(4-chlorophenyl)-1,1-dichloroethylene (DDE) and PCBs. In addition to PCBs, the soils from Enewetak Atoll contained PCTs. PCTs were not detected in the sediment samples from Bikini Atoll. The results suggest local pollution sources of PCBs, PCTs, and OCPs.     

Accumulation and maternal transfer of polychlorinated biphenyls in Steller Sea Lions (Eumetopias jubatus) from Prince William Sound and the Bering Sea, Alaska

The western stock of the Steller sea lion (Eumetopias jubatus) in the northern Pacific Ocean has declined by approximately 80% over the past 30 years. This led to the listing of this sea lion population as an endangered species in 1997. Chemical pollution is a one of several contributing causes. In the present study, 145 individual PCBs were determined in tissues of male sea lions from Tatitlek (Prince William Sound) and St. Paul Island (Bering Sea), and placentae from the Aleutian Islands. PCBs 90/101, 118, and 153 were abundant in all the samples. The mean toxic equivalents (TEQ) were 2.6, 4.7 and 7.4 pg/g lw in the kidney, liver, and blubber samples, respectively. The mean TEQ in placentae was 8 pg/g lw. Total PCBs concentrations (2.6-7.9 μg/g lw) in livers of some males were within a range known to cause physiological effects. Further suggesting the possibility of adverse effects on this stock.     

江苏省污染减排与空气质量变化相关性分析

利用2000—2007年大气污染物排放量数据和同期环境空气质量监测数据,分析了江苏省主要大气污染物减排与环境空气质量变化的相关性。结果表明,近年来江苏省SO2排放量与环境空气中SO2浓度存在正相关,而烟尘和粉尘排放总量与空气中可吸入颗粒物的浓度呈现出弱的负相关关系。对江苏省经济发展和环境关系的进一步分析揭示,江苏省环境库兹涅茨曲线呈现出倒U型关系,表明江苏省已经进入经济环境双赢区间,但近年来政策对经济环境关系的影响突出。该研究对中国十二五环境管理政策的制定有着重要的参考意义。     

Bioconversion of dairy manure by black soldier fly (Diptera: Stratiomyidae) for biodiesel and sugar production

Modern dairies cause the accumulation of considerable quantity of dairy manure which is a potential hazard to the environment. Dairy manure can also act as a principal larval resource for many insects such as the black soldier fly, Hermetia illucens. The black soldier fly larvae (BSFL) are considered as a new biotechnology to convert dairy manure into biodiesel and sugar. BSFL are a common colonizer of large variety of decomposing organic material in temperate and tropical areas. Adults do not need to be fed, except to take water, and acquired enough nutrition during larval development for reproduction. Dairy manure treated by BSFL is an economical way in animal facilities. Grease could be extracted from BSFL by petroleum ether, and then be treated with a two-step method to produce biodiesel. The digested dairy manure was hydrolyzed into sugar. In this study, approximately 1248.6 g fresh dairy manure was converted into 273.4 g dry residue by 1200 BSFL in 21 days. Approximately 15.8 g of biodiesel was gained from 70.8 g dry BSFL, and 96.2 g sugar was obtained from the digested dairy manure. The residual dry BSFL after grease extraction can be used as protein feedstuff.     

和谐社会视野下的环境伦理学

20世纪是人类科学取得巨大成就的时期,也是地球环境急剧恶化、环境危机全球化和日益严重的时期.本文通过环境整体主义道德哲学的核心意识结构阐释人类追求的最高价值即是生态系统的整体利益,它既涵盖了整体主义的和谐发展论,又包括完整的环境正义观.