寒区多孔介质中LNAPL迁移的多场耦合模拟

建立了包含水、气、NAPL、固(冰)四相的温度场、流场及化学场多场耦合模型,适用于定量模拟LNAPL泄漏过程中发生冻结后的迁移分布.通过与非冻条件下LNAPL迁移模型对比,模拟结果显示,冻结条件下因冰的形成LNAPL会发生与非冻条件下不同的迁移行为,冰的形成阻碍LNAPL下渗,并产生冻结势使LNAPL向地表方向迁移.相...     

铁元素对有机物厌氧降解的影响研究

不同价态的铁元素氧化还原性不同,对有机物的厌氧生物降解过程的影响也不同。以邻氟苯酚和硝基苯为目标污染物,投铁量为20～100mg／L的条件下,单质铁能加速硝基苯的厌氧降解,对2-氟酚降解的影响则很小;二价铁和三价铁对两种物质都表现出一定的抑制作用,投加浓度越高,抑制作用越明显。     

基于利益相关群体的碳减排策略与潜力分析——以苏州市为例

本研究基于苏州市低碳试点工作实施方案,识别了苏州市重点减排领域,采用国家温室气体排放清单,估算了苏州"十二五"(2011—2015)期间碳排放量,并利用情景分析法预测了2016—2025年基准情景和综合减排情景碳排放趋势,分析了各重点排放领域减排贡献率。在此基础上,将减排策略按照自愿、监管、自愿与监管相结合的方式分别从不同利益相关群体进行梳理,分析不同群体减排潜力。结果表明:(1) 2015年,苏州市碳排放量约为2.35亿吨,2011—2015年,重点排放领域为工业能源消耗、建筑、交通、电力行业。(2)采用综合减排方案能在2020年左右达到峰值,之后缓慢下降,但交通部门碳排放仍有一定增加。(3)碳减排策略由多个利益相关群体共同作用产生减排贡献。对苏州市低碳试点方案的分析表明,当地政策制定者的减排贡献最高,其后是基础设施建设者和运营者,最后是基础设施使用者。     

兰州市西固区土壤中PAHs污染特征及来源解析

为了解石油工业区土壤中PAHs(多环芳烃)的污染特征、来源及潜在危害,选择兰州市西固区为研究区域,系统采集表层土壤样品及部分剖面样品,采用GC-MS检测方法,分析了土壤中PAHs的污染水平与分布、来源及潜在致癌风险. 结果表明:研究区表层(0~20 cm)土壤中w(∑PAHs)(22种PAHs的总质量分数)在535～32 300 μg/kg之间;PAHs在土壤剖面的纵向分布上主要集中在5～10 cm,在0～25 cm范围内变化不明显;表层土壤中PAHs主要以2～3环为主. 相关性分析显示,土壤中w(∑PAHs)与w(TOC)无显著的相关性,表明TOC并非影响土壤中PAHs持留的重要因素. 研究区土壤中PAHs主要来源于石油、生物质和煤炭的燃烧,∑TEQ_BaP (22种PAHs的毒性当量浓度,以苯并芘等效浓度计)平均值为190 μg/kg,表明土壤中PAHs的潜在致癌性较低.      

Divergent Perspectives on Expert Disagreement: Preliminary Evidence from Climate Science,Climate Policy,Astrophysics, and Public Opinion

We report the results of an exploratory study that examines the judgments of climate scientists, climate policy experts, astrophysicists, and non-experts (N?=?3367) about the factors that contribute to the creation and persistence of disagreement within climate science and astrophysics and about how one should respond to expert disagreement. We found that, as compared to non-experts, climate experts believe that within climate science (i) there is less disagreement about climate change, (ii) methodological factors play less of a role in generating disagreements, (iii) fewer personal or institutional biases influence climate research, and (iv) there is more agreement about which methods should be used to examine relevant phenomena we also observed that the uniquely American political context predicted experts’ judgments about some of these factors. We also found that, in regard to disagreements concerning cosmic ray physics, and commensurate with the greater inherent uncertainty and data lacunae in their field, astrophysicists working on cosmic rays were generally more willing to acknowledge expert disagreement, more open to the idea that a set of data can have multiple valid interpretations, and generally less quick to dismiss someone articulating a non-standard view as non-expert, than climate scientists were in regard to climate science.     

转盘式光催化燃料电池处理染料废水

采用阳极氧化法制备转盘式TiO_2阳极,设计并开发了转盘式光催化燃料电池(PFC),探讨了圆盘转速对PFC中染料降解效果的影响。实验结果表明:随着圆盘转速的提高,污染物和光电界面反应产物的传质作用得以强化,罗丹明B降解率提高;在圆盘转速为1 600 r/min、反应时间为60 min的条件下,罗丹明B降解率达90.8%,是圆盘转速为0 r/min时的8.5倍;光电流也随着圆盘转速的提高而提高,但提高幅度远小于罗丹明B降解率的提高幅度;同时,加强传质作用后再外加电压对PFC催化降解性能的提高作用有限。     

自我剥削、禀赋效应与农地流转潜在市场发育——兼论经济欠发达地区小农户生产方式转型

以家庭均包制为主要经营特征的农村土地制度曾一度引致农户农业生产积极性的提高和农业生产效率的快速增长,但由此导致的细碎化小规模的农地经营特征和农业生产成本的上升却造成了农地经营的自我剥削现象普遍存在,加之传统的村庄惯习和土地占有关系诱致的农户对农地的禀赋效应,共同导致农户农地经营的自我剥削属性与土地的市场处置行为呈现出内在运行机制不一致性。为此,本文采用引入交叉项的Probit模型,并利用江西省丰城市和遂川县的706户农户调查数据经验分析了小农户的自我剥削和农地禀赋效应对农地流转潜在市场发育的影响。理论分析表明,农地经营的自我剥削特征与农地市场化具有一致性倾向,但农地的人格化财产属性引致的农户禀赋效应造成了农户农地经营自我剥削感知度的下降,并削弱了要素经营属性与市场配置行为的匹配。经验分析结果发现,小农户低效率农地经营导致的自我剥削与农地禀赋效应分别激励农地流转市场的潜在供给和需求。同时,农地禀赋效应弱化了自我剥削对农地流转潜在需求和供给的诱发作用。为此,本文认为降低农户的土地禀赋效应是欠发达地区小农户转型的总体方向,它为农地由小农户流向生产大户和培育部分小农户成为新型农业经营主体提供保障。文章主要从家庭决策的利益导向化、农地流转市场与劳动力市场发展的不一致性及农村制度供给等维度提出了经济欠发达地区小农户转变农业生产方式,跳出自我剥削陷阱的政策建议。具体措施包括:1切实保障小农户的基本权益,提高他们在家庭资源配置中的预期收益;2在初次规模经营补贴、农业基本补贴机制转变、经营者生产奖励、专业技能培训、市场信息供给等层面加大投入力度,同时完善农村社会保障体系,以降低小农户转型的难度与风险。     

武汉城市圈城市空间相互作用时空演变分析

引入人口重心、GIS网络分析及时序全局主成分分析法对传统引力模型进行修正,由此测算城市潜力值,以定量测度2002~2013年武汉城市圈城市空间相互作用强度,并结合IDW空间插值法和CTCSTP算法揭示出其时空演变规律。结果表明:(1)武汉城市圈各城市与其他城市间相互作用总强度总体呈增长趋势,其中武汉市增幅远高于其他城市,其与孝感-鄂州-黄石形成显著的轴线式发展格局,其余城市始终为空间联系弱区地带。(2)武汉市辐射带动作用日趋强劲,辐射范围逐年扩大并呈现一定的"圈层式"分布,其余城市辐射带动作用较弱,仅孝感市略显对外辐射趋势。(3)整个区域的空间相互作用表现出显著的"西南部低、北部高、东部适中"的空间分异特征,且其重心由南向北转移明显,区域发展不均衡特性显著。     

Weather,climate, politics,or God? Determinants of American public opinions toward global warming

2012 American National Election Study data supplemented with monthly temperature data from the United States Historical Climatology Network are used to examine how religion, politics, and weather and climate affect views of global warming. Evangelical fundamentalism is the most consistent factor among all religion-related variables in determining perceptions of global warming, those more oriented toward evangelical fundamentalism being less likely than others to believe in the existence, anthropogenic cause, and adverse impact of global warming. Controlling for the effects of traditional political predisposition variables, including party identification and political ideology, support for the Tea Party plays a dominant role in determining views of global warming; support for the Tea Party leading to higher likelihood of disbelief in the existence, anthropogenic cause, and negative impact of global warming. Warming winters coupled with cooling springs of the past decade are positively related with belief in the existence of global warming.     

Per-capita estimations of long-term historical land use and the consequences for global change research

Changes in land use and land cover are important in global climate change, but the many uncertainties in historical estimates seriously hamper climate modelling. We collected new data on estimated per capita land use over the last two millennia, using new data sources from the Humanities. In general, and in agreement with literature, we found that per capita land use indeed has not been constant in the past, but differ per region and over time. Land use in the distant past was mostly less than 1 ha/cap. However, the recently colonised regions show much higher values and have experienced a much higher per capita land use for the recent past. Most known trajectories follow a concave or bell-shaped curve towards the present.