2010年广州亚运会期间灰霾天气分析

使用广州地区气象资料,重点研究了 2010 年广州亚运会期间的灰霾天气特征. 结果发现,2010 年 11 月广州出现灰霾天气 5 d,较近年平均水平明显偏少,但 2008—2010 年的污染气象条件分析表明,2010 年的扩散条件较 2008 和 2009 年均较差,说明 2010 年广州亚运会前期的各项减排措施取得了明显成效. 作为对照,自 20 世纪 80 年代初开始,广州地区的能见度急剧恶化并导致灰霾天数增加,每年 10 月至次年 4 月的旱季灰霾天数较多,改革开放以来,每年 11 月份的灰霾天气大幅增加,并于 1994 和1999 年分别出现了最多的17 d. 2000 年以后,11 月份灰霾天气最多为 12 d,出现在 2005 年; 最少为 3 d,分别出现在 2002 和 2003 年. 广州市空气质量逐年恶化的趋势不容乐观,珠江三角洲复合型新型空气污染日趋严重的态势非常严峻; 且区域性特征明显,治理难度加大; 广州周边的佛山、清远、东莞、江门的灰霾天气都比广州多,对广州治理灰霾天气形成了压力. 因而 2010 年 11 月灰霾天气的明显减少,更说明区域联动、机动车单双号限行、重点工业污染源调控、严控垃圾秸秆焚烧等减排措施效果明显.     

用H-Kappa方法反演龙门山断裂带及其邻区的莫霍面深度及波速比分布

利用龙门山断裂带及其邻近地区地震台站的远震波形记录,采用时间域迭代反褶积技术求取接收函数,并用多次反射波能量扫描求极大值和波形叠加反演的方法(H-Kappa方法)计算出台站下方的莫霍面深度和波速比。结果显示:莫霍面位于扬子地台西缘部分向西侧倾斜缓降,深度在40～48 km变化,地壳平均波速比值为1.81;都江堰、汶川、耿达一带处在龙门山推覆体范围之内的莫霍面起伏变化不大,深度在45 km左右,地壳平均波速比值为1.707 5;龙门山断裂带西侧的松潘—甘孜地块的平均地壳波速比为1.76,莫霍面深度南面部分比北面深约10 km,呈南深北浅状。     

灌溉管理改革的进展、特征及决定因素:黄河流域灌区的实证研究

论文采用两年的面板数据实证研究了我国黄河流域灌区灌溉管理改革的进展、特征及决定因素。研究结果表明,自20世纪90年代开始,黄河流域灌区灌溉管理改革取得了很大的进展,传统的集体管理已经逐步被承包管理和用水协会管理所取代,不同管理制度下农民参与的程度与管理的透明度都有所区别,政府的政策干预在促进灌溉管理改革上发挥了十分重要的作用,改革具有明显的政策导向性。在未来的灌溉管理改革中,政府部门应进一步出台相关鼓励改革政策,积极引导广大农民参与到改革的事业中,促进改革在更加广阔的农村地区的有效推进和良性发展。     

基于公路网络的长江三角洲旅游景点可达性格局研究

论文运用GIS软件,定量分析了长江三角洲旅游景点可达性。通过分析发现:长江三角洲旅游景点资源的可达性较好,整个区域的平均可达性时间为25.89 min,景点的可达性在30 min以内的区域达到了69.79%,可达性空间分布具有明显的交通指向性,人文景点可达性好的区域相对于自然景点更加集中。并以县域为统计单元,分析了所有景点、人文景点、自然景点三种类型的空间关联情况,均呈弱集聚格局,可达性热点区域的分布都表现为以上海为核心的圈层结构,冷点区域分布在长江三角洲区域的外围地区。在上述分析的基础上,将影响景点可达性的因素归纳为4个,即:旅游景点分布、路网结构的地区差异、自然环境和人文环境。     

上海市城区春节和“五一”节期间大气挥发性有机物的组成特征

挥发性有机物(VOCs)是对流层臭氧和二次有机气溶胶等二次污染生成过程的关键前体物.研究VOCs的浓度水平、组成特征和反应活性对揭示复合型大气污染的形成机制具有重要意义.本研究利用在线气相-氢离子火焰法测量了2009年春节和"五一"节期间上海市城区大气中56种VOCs.结果表明,上海市城区大气受机动车尾气排放源影响明显,VOCs浓度日变化特征呈双峰状,与上下班交通高峰基本吻合.大气中VOCs平均体积分数为(28.39±18.35)×10-9;各组分百分含量依次为:烷烃46.6%,芳香烃27.0%,烯烃15.1%,乙炔11.2%.用OH消耗速率和臭氧生成潜势(OFP)评估了VOCs大气化学反应活性,结果表明,上海市城区大气VOCs化学反应活性与VOCs体积浓度相关性良好;VOCs活性与乙烯相当,平均化学反应活性较强;OH消耗速率贡献最大的物种是烯烃51.2%和芳香烃31.8%;OFP贡献最大的物种是芳香烃53.4%和烯烃30.2%;对臭氧生成贡献最大的关键活性物种为丙烯、乙烯、甲苯、二甲苯以及丁烯类物质.     

Evaluation of mercury speciation and removal through air pollution control devices of a 190 MW boiler

Air pollution control devices (APCDs) are installed at coal-fired power plants for air pollutant regulation. Selective catalytic reduction (SCR) and wet flue gas desulfurization (FGD) systems have the co-benefits of air pollutant and mercury removal. Configuration and operational conditions of APCDs and mercury speciation a ect mercury removal e ciently at coal-fired utilities. The Ontario Hydro Method (OHM) recommended by the U.S. Environmental Protection Agency (EPA) was used to determine mercury speciation simultaneously at five sampling locations through SCR-ESP-FGD at a 190 MW unit. Chlorine in coal had been suggested as a factor a ecting the mercury speciation in flue gas; and low-chlorine coal was purported to produce less oxidized mercury (Hg2+) and more elemental mercury (Hg0) at the SCR inlet compared to higher chlorine coal. SCR could oxidize elemental mercury into oxidized mercury when SCR was in service, and oxidation e ciency reached 71.0%. Therefore, oxidized mercury removal e ciency was enhanced through a wet FGD system. In the non-ozone season, about 89.5%–96.8% of oxidized mercury was controlled, but only 54.9%–68.8% of the total mercury was captured through wet FGD. Oxidized mercury removal e ciency was 95.9%–98.0%, and there was a big di erence in the total mercury removal e ciencies from 78.0% to 90.2% in the ozone season. Mercury mass balance was evaluated to validate reliability of OHM testing data, and the ratio of mercury input in the coal to mercury output at the stack was from 0.84 to 1.08.     

Effects of sediment dredging on water quality and zooplankton community structure in a shallow of eutrophic lake

Effects of suction dredging on water quality and zooplankton community structure in a shallow of eutrophic lake,were evaluated.The results showed that a decreasing trend for levels of phosphorus,organic matter,total suspended solids,Chlorophyll a and Secchi transparency in the water column was found,while levels of water depth,electrical conductivity,total dissolved solids and NO 3--N concentration increased markedly post-dredging.The effects of dredging on dissolved oxygen,pH value and temperature were alm...     

Cretaceous choristoderan reptiles gave birth to live young

Viviparity (giving birth to live young) in fossil reptiles has been known only in a few marine groups: ichthyosaurs, pachypleurosaurs, and mosasaurs. Here, we report a pregnant specimen of the Early Cretaceous Hyphalosaurus baitaigouensis, a species of Choristodera, a diapsid group known from unequivocal fossil remains from the Middle Jurassic to the early Miocene (about 165 to 20 million years ago). This specimen provides the first evidence of viviparity in choristoderan reptiles and is also the sole record of viviparity in fossil reptiles which lived in freshwater ecosystems. This exquisitely preserved specimen contains up to 18 embryos arranged in pairs. Size comparison with small free-living individuals and the straight posture of the posterior-most pair suggest that those embryos were at term and had probably reached parturition. The posterior-most embryo on the left side has the head positioned toward the rear, contrary to normal position, suggesting a complication that may have contributed to the mother’s death. Viviparity would certainly have freed species of Hyphalosaurus from the need to return to land to deposit eggs; taking this advantage, they would have avoided intense competition with contemporaneous terrestrial carnivores such as dinosaurs.     

南非:环境保护的私人力量

<正>南非位于南半球,非洲大陆的最南端,地处南纬22度到35度之间,面积为121.9万平方公里,人口约为4700万,是非洲大陆经济最发达的国家,因其多民族和多元文化的融合而被称为"彩虹之国"。南非境内共有20座国家公园,此外还有不少的省区管理和私人运营     

围网养殖对洪湖水质的影响分析

文章从围网养殖对洪湖水质影响的角度出发,依据1990～2006年在洪湖实测的水质数据分析了洪湖水质的时空变化过程及趋势,并发现水质指标中总氮的超标量变化明显。利用环境污染综合指数法,通过围网内和围网外以及围网前和围网后不同水文期的水质情况对比,对洪湖水质变化进行综合评价。结果表明围网内的环境污染综合指数在枯水期要远大于围网外的,围网养殖对湖泊的局部污染严重;围网前水质基本可以达到Ⅱ类水质标准,开始围网后洪湖水质逐步恶化,且围网养殖面积与水质恶化的程度有着相同的变化趋势,总氮的含量变化尤为明显,随着围网养殖规模面积的扩大急速增加。