A new approach to spatial source apportionment of haze pollution in large scale and its application in China

Long-lasting expansion of haze pollution in China has already presented a stern challenge to regional joint prevention and control. There is an urgent need to enlarge and reconstruct the coverage of joint prevention and control of air pollution in key area. Air quality models can identify and quantify the regional contribution of haze pollution and its key components with the help of numerical simulation, but it is difficult to be applied to larger spatial scale due to the complexity of model parameters. The time series analysis can recognize the existence of spatial interaction of haze pollution between cities, but it has not yet been used to further identify the spatial sources of haze pollution in large scale. Using econometric framework of time series analysis, this paper developed a new approach to perform spatial source apportionment. We applied this approach to calculate the contribution from spatial sources of haze pollution in China, using the monitoring data of particulate matter (PM_2.5) across 161 Chinese cities. This approach overcame the limitation of numerical simulation that the model complexity increases at excess with the expansion of sample range, and could effectively deal with severe large-scale haze episodes.     

Catalytic oxidation of CO over Pt/Fe3O4 catalysts: Tuning O2 activation and CO adsorption

• Strong metal-support interaction exists on Pt/Fe₃O₄ catalysts. • Pt metal particles facilitate the formation of oxygen vacancies on Fe₃O₄. • Fe₃O₄ supports enhance the strength of CO adsorption on Pt metal particles. The self-inhibition behavior due to CO poisoning on Pt metal particles strongly impairs the performance of CO oxidation. It is an effective method to use reducible metal oxides for supporting Pt metal particles to avoid self-inhibition and to improve catalytic performance. In this work, we used in situ reductions of chloroplatinic acid on commercial Fe₃O₄ powder to prepare heterogeneous-structured Pt/Fe₃O₄ catalysts in the solution of ethylene glycol. The heterogeneous Pt/Fe₃O₄ catalysts achieved a better catalytic performance of CO oxidation compared with the Fe₃O₄ powder. The temperatures of 50% and 90% CO conversion were achieved above 260°C and 290°C at Pt/Fe₃O₄, respectively. However, they are accomplished on Fe₃O₄ at temperatures higher than 310°C. XRD, XPS, and H₂-TPR results confirmed that the metallic Pt atoms have a strong synergistic interaction with the Fe₃O₄ supports. TGA results and transient DRIFTS results proved that the Pt metal particles facilitate the release of lattice oxygen and the formation of oxygen vacancies on Fe₃O₄. The combined results of O₂-TPD and DRIFTS indicated that the activation step of oxygen molecules at surface oxygen vacancies could potentially be the rate-determining step of the catalytic CO oxidation at Pt/Fe₃O₄ catalysts. The reaction pathway involves a Pt-assisted Mars-van Krevelen (MvK) mechanism.     

重庆三叠系碳酸盐岩热储热水水文地球化学特征

地下热水的水文地球化学特征研究有利于地下热水的开发,对重庆三叠系碳酸盐岩热储热水的研究可以更好地实现重庆地下热水的可持续开发。通过2009年1月和2009年7月对重庆市三叠系碳酸盐岩热储热水进行野外监测、取样和室内分析,发现重庆三叠系碳酸盐岩热储热水水化学性质相近,pH呈中性,水温30℃~50℃,电导率为1 320 μs/cm~3 250 μs/cm,水化学类型为SO₄-Ca(Mg)型,是典型的碳酸盐岩热储中-低温地下热水。温泉水的主要阳离子为Ca²⁺和Mg²⁺,阴离子为SO₄^2-和HCO₃^-,除青木关温泉外,SO₄^2-和Ca²⁺、Mg²⁺随时空变化较小,体现了碳酸盐岩中石膏与地下热水的水-岩作用对地下热水水文地球化学特征的控制。热水中的方解石和白云石都处于饱和与不饱和的临界状态,没有明显钙华沉积的现象;Na-K-Mg-Ca图解显示各个季节地下热水的物质来源基本一致,均没有达到水岩平衡状态。     

常见金属硫化物电化学反应环境效应及其影响因素分析

金属硫化物矿物作为重要的金属矿产资源之一,在自然界广泛分布并易氧化(电化学反应)引起重金属离子和酸性矿山废水污染的环境效应。本文以黄铁矿和黄铜矿为例全面分析了金属硫化物矿物环境效应产生机制,以及影响金属硫化物矿物电化学反应的各种因素,指出了当前研究存在的不足。这对金属硫化物矿区环境污染的源头控制与修复具有重要的指导意义。     

地方政府土地出让策略互动行为的检验及其影响分析

本文以山东省设区市地方政府土地出让行为作为研究对象,通过构建空间面板模型,从价格和数量两个维度,全面检验了地方政府商服、住宅、工业用地出让的策略互动行为,并利用空间计量工具,分析了地方政府土地出让策略互动行为的影响。研究发现:(1)山东省内地方政府商服、住宅、工业用地出让价格以及工业用地出让量存在显著的策略互动,地方政府的商服、住宅、工业用地出让价格以及工业用地出让量,不仅会受城市自身情况的约束,还会受邻近地区地方政府土地出让行为的影响,外在表现为你涨我跌、你增我减的反向变动格局;(2)由于未考虑策略互动,传统计量经济学非空间面板模型对地方政府土地出让行为影响因素的估计普遍存在偏误。对于商服用地出让价格,第三产业比重、人口密度的影响分别被低估了33.33%、13.08%;对于住宅用地出让价格,人口城镇化率、人均可支配收入的影响分别被低估了20.00%、9.98%,人口密度的影响被高估了32.34%;对于工业用地出让价格,人均外商直接投资的影响被高估了3.68%;对于工业用地出让量,第二产业比重、地均工业产值的影响分别被高估了13.95%、31.36%;(3)地方政府土地出让行为的影响因素普遍存在明显的空间溢出效应。对于商服用地出让价格,具有空间溢出效应的影响因素为人口密度;对于住宅用地出让价格,具有空间溢出效应的影响因素为人口城镇化率、人口密度、人均可支配收入;对于工业用地出让价格,具有空间溢出效应的影响因素为人均外商直接投资、地均固定资产投资;对于工业用地出让量,具有空间溢出效应的影响因素为第二产业比重、地均固定资产投资。     

Estimating Water Budgets and Vertical Leakages for Karst Lakes in North‐Central Florida (United States) Via Hydrological Modeling1

Lin, Zhulu, 2011. Estimating Water Budgets and Vertical Leakages for Karst Lakes in North‐Central Florida (United States) Via Hydrological Modeling. Journal of the American Water Resources Association (JAWRA) 1‐16. DOI: 10.1111/j.1752‐1688.2010.00513.x Abstract: Newnans, Lochloosa, and Orange Lakes are closely hydrologically connected karst lakes located in north‐central Florida, United States. The complex karst hydrology in this region poses a great challenge to the hydrological modeling that is essential to the development of Total Maximum Daily Loads for these lakes. We used a Hydrological Simulation Program – Fortran model coupled with the parallel Parameter ESTimation model calibration and uncertainty analysis software to estimate effectively the hydrological interactions between the lakes and the underlying upper Floridan aquifer and the water budgets for these three lakes. The net results of the lake‐groundwater interactions in Newnans and Orange Lakes are that both lakes recharge the underlying upper Floridan aquifer, with the recharge rate of the latter one magnitude greater than that of the former. However, for Lochloosa Lake, the net lake‐groundwater interaction is that the lake gains water from groundwater in a significant amount, approximately 40% of its total terrestrial water input. The annual average vertical leakages estimated for Newnans, Lochloosa, and Orange Lakes are 6.0 × 10⁶, ?8.9 × 10⁶, and 44.4 × 10⁶ m³, respectively. The average vertical hydraulic conductance (K_v/b) of the units between a lake bottom and the underlying upper Floridan aquifer in this region are also estimated to be from 1.26 × 10^?4 to 1.01 × 10^?3 day^?1.     

大型渡槽结构动力学研究进展

大型渡槽是灌区生命线工程中的关键性建筑物,其在地震及风载作用下的安全性已是渡槽建设的瓶劲,也是国内外研究的热点。渡槽结构的抗震、减震和抗风技术的核心是渡槽结构动力学的问题,而渡槽结构动力学系属流固耦合(FSI)系统的动力学范畴。在已有研究的基础上,首先对渡槽结构FSI系统模型的研究进行了总结和评述;然后简述了渡槽结构动力特性和响应的求解技术以及抗震、隔震、减震与抗风技术的研究概况;最后总结了渡槽结构动力学的研究进展,提出了该学科进一步研究的内容和方法。     

潮土中磷锌交互作用机制探讨及磷对锌吸附-解吸的影响

采用室内培养和吸附解吸两种方法,探讨了潮土中磷、锌交互作用机制。结果表明：土壤中DTPA提取态锌质量分数随添加锌量的增加而增加,低磷质量分数处理可提高土壤锌有效性,但高磷质量分数处理却降低了土壤锌的有效性;土壤速效磷质量分数均随锌添加量的增加而有所降低。在施锌25 mg.kg-1背景下,土壤中DTPA提取态锌质量分数随施磷质量分数的增加呈先增加后降低趋势,在添加磷量小于180 mg.kg-1时,土壤DTPA提取态锌质量分数显著地高于其他处理,但随添加磷量的增加,土壤DTPA提取态锌质量分数显著降低,当磷添加量大于540 mg.kg-1时,土壤DTPA提取态锌质量分数明显低于其他磷处理,说明当添加磷量小于180 mg.kg-1时,磷提高土壤中锌有效性的主要机制是二者竞争吸附土壤胶体表面吸附点位的竞争机制;当添加磷量大小540 mg.kg-1时,磷影响锌有效性的主要机制为沉淀作用。在土壤施磷量为180 mg.kg-1时,随添加锌质量分数的提高,土壤中速效磷质量分数呈先升高后降低趋势。吸附-解吸研究表明,随土壤中速效磷质量分数的提高（27.60~2773.86 mg.kg-1）,土壤对锌的吸附量先降低再增加,而KCl解吸的锌量却是先增加再降低。因此潮土中磷锌交互作用机制为,土壤中磷和锌质量分数均较低时,磷与锌有效性呈协同作用;当磷或锌质量分数过高时,协同作用减弱;磷和锌质量分数再增加二者的有效性将出现拮抗作用。     

大气作用下膨胀土地基的水分迁移与胀缩变形分析

运用土体渗流和蒸发理论,建立了大气-非饱和土相互作用模型;以现场观测的气象数据作为边界条件,进行了地基土中水分迁移的数值模拟,得到了大气作用下地基土体含水量的动态分布规律.计算结果表明,地基土中含水量变化幅度随深度增加而递减,3.5m深度以下土体的体积含水量基本不变,从而确定了南宁地区膨胀土地基的大气影响层深度为3.5...     

铜绿假单胞菌对铜和铅的吸附

研究了铜绿假单胞菌(Pseudomonas aeruginosa)对Cu和Pb的吸附特性.结果表明,相同条件下,该菌株对Cu~(2+)的吸附率低于Pb~(2+).对于单一重金属体系,吸附率均随时间的延长先上升后平稳变化,2 h达到稳定.吸附率随投菌量的增加先迅速增加,之后趋于平稳.对于Cu~(2+),投菌量为1 g·L~(-1)时吸附率达到稳定,而Pb~(2+)的吸附效果达到平稳时的投菌量为0.5 g·L~(-1).单位质量菌体对Cu~(2+)、Pb~(2+)的吸附量随投菌量的增加而下降.pH为3时,菌体的吸附效果较差,当pH为5~8时,2种重金属的吸附效果较高.对于活菌,Pb~(2+)对菌体吸附Cu~(2+)有抑制作用,而Cu~(2+)对菌体吸附Pb~(2+)的影响无明显规律.对于失活菌,P.aeruginosa吸附Pb~(2+)和Cu~(2+)的效果均随共存重金属浓度的增大而降低,但Cu~(2+)对Pb~(2+)的影响比Pb~(2+)对Cu~(2+)的影响更显著.扫描电镜观察发现,吸附后的菌体较吸附前聚集性更好.总体而言,P.aeruginosa能对水体中共存的Cu~(2+)和Pb~(2+)有较好的吸附效果.