PANI/Bi_2MoO_6复合光催化剂的制备、表征及其可见光催化性能

采用原位氧化聚合法制备了PANI/Bi_2MoO_6复合光催化剂,采用XRD、SEM、PL和UV-Vis DRS等技术对其进行了表征,并将其用于罗丹明B(Rh B)的可见光催化降解。表征结果显示:聚苯胺(PANI)包覆于Bi_2MoO_6微球表面,促进了光生载流子的迁移,抑制了光生电子-空穴对的复合,拓宽了催化剂的可见光响应范围。实验结果表明:PANI/Bi_2MoO_6复合光催化剂具有较高的可见光催化活性和良好的稳定性,当w(PANI)为36%、光照90 min时Rh B去除率达90.4%,明显优于纯Bi_2MoO_6;该体系中,空穴和·O2-在污染物的降解过程中起主要作用;PANI和Bi_2MoO_6之间形成了异质结结构,使光生电子-空穴对有效分离。     

纳米零价铁的微生物毒性效应研究进展

纳米零价铁(nanoscale zero-valent iron,NZVI)是一种新型的地下水修复材料,NZVI的生物安全性研究已经引起了世界各国学者的广泛关注。本文综述了国内外有关NZVI微生物毒性的研究成果,重点介绍了NZVI对微生物的毒性效应及致毒机理,归纳总结了影响NZVI颗粒毒性效应的各种因素,并对未来NZVI材料毒性研究的发展方向进行了展望,以期为NZVI的生物安全性研究提供参考。     

Moderation effect of planning on housing development along the French Atlantic coast: findings from an event history hazard model

Laws and bylaws are regularly challenged for their effectiveness in containing urbanisation sprawl and, conversely, for the constraints they put on development projects. From a French case study, we used survival analysis to disentangle a complex mix of influences on the distribution of residential construction over a 42-year observation period at plot scale when almost everything changes simultaneously. We found that integrated laws and bylaws can slow down coastal urbanisation but do not stop it. Although land planning is becoming more effective, it still provides ample opportunity for residential development because other factors, like distance to existing infrastructure, exert a far stronger influence than the protection of coastal areas. Therefore, this article contributes to filling a knowledge gap about the founding role of public policies on land use dynamics.     

Comparison of the energetic performance of a binary cycle and a flash evaporation binary cycle,using low-enthalpy geothermal energy

In this article, the comparison of the energetic performance of a binary cycle and a modified binary cycle with flash evaporation is presented, both using a low-enthalpy geothermal resource. The comparative analysis is based on two main discourses: the first one evaluates a conventional binary cycle (CBC) with isopentane as working fluid in order to validate and compare the generated data with those reported in similar studies; the second one uses the same input parameters for both cycles, obtaining the cases in which the modified binary cycle is the most viable choice to use. In addition to the above, several aspects are considered when selecting the most suitable working fluid, and the use of water as working fluid is introduced. When the temperature of the geothermal resource is below 140 °C, and the ambient temperature is 25 °C, the flash evaporation binary cycle, using water as working fluid, shows an improved performance compared to a CBC, with a theoretical output over 1000 kWe. This may encourage new areas of opportunity for power generation, not only with low- and medium-enthalpy geothermal energy, but also with other renewable energy sources such as solar.     

126kV双断口快速真空断路器仿真研究

快速真空断路器因其动作速度快、可靠性高、动作分散性小等特点,目前多应用于中低压配用电系统。以一种限制变压器励磁涌流的126 kV双断口罐式结构的快速真空断路器为例,采用有限元仿真研究了其电场、磁场、温度场分布。仿真结果表明,采用罐式双断口结构的快速真空断路器的绝缘性能、磁场分布及通流性能均满足设计要求。     

Assesment of Trace Elements and Organic Pollutants from a Marine Oil Complex into the Coral Reef System of Cayo Arcas, Mexico

Possible contaminants produced by the Petroleos Mexicanos (PEMEX) marine oil complex in the vicinity of the Cayo Arcas (Mexico) coral reef ecosystem were evaluated by analyzing sediments and sea water for hydrocarbons and metal elements. We found that the concentrations of aliphatic hydrocarbons in the sea water were generally low, with the highest values detected near the oil station; the concentration of polycyclic aromatic hydrocarbons (PAHs) was generally below the detection limit. The hydrocarbons found in the sediments seem to have a pyrogenic origin, and were probably produced by marine traffic in the study area. The total PAH concentration did not exceed the NOAA criteria, although levels of some individual PAHs did. The only metal detected in the sea water at high concentrations was nickel. The Ni/V ratio in the sediments indicates the contribution of crude oil to the system. The high content of Ni and Zn was attributed to the ballast waters from the oil tankers that load at the station's monobuoys. The presence of fine sediments that commonly originate from terrestrial ecosystems supported this assumption.     

A Spatially Explicit Resource-Based Approach for Managing Stream Fishes in Riverscapes

The article describes a riverscape approach based on landscape ecology concepts, which aims at studying the multiscale relationships between the spatial pattern of stream fish habitat patches and processes depending on fish movements. A review of the literature shows that few operational methods are available to study this relationship due to multiple methodological and practical challenges inherent to underwater environments. We illustrated the approach with literature data on a cyprinid species (Barbus barbus) and an actual riverscape of the Seine River, France. We represented the underwater environment of fishes for different discharges using two-dimensional geographic information system-based maps of the resource habitat patches, defined according to activities (feeding, resting, and spawning). To quantify spatial patterns at nested levels (resource habitat patch, daily activities area, subpopulation area), we calculated their composition, configuration, complementation, and connectivity with multiple spatial analysis methods: patch metrics, moving-window analysis, and least cost modeling. The proximity index allowed us to evaluate habitat patches of relatively great value, depending on their spatial context, which contributes to the setting of preservation policies. The methods presented to delimit potential daily activities areas and subpopulation areas showed the potential gaps in the biological connectivity of the reach. These methods provided some space for action in restoration schemes.     

2008年北京市大气质量的灰色预测

运用灰色关联分析方法对北京市大气主要污染物质进行了分析,得出PM10、TSP和SO2是主要污染因子。在此基础上,运用灰色系统理论建模方法,分别建立主要污染因子的预测模型。运用该模型预测出到2008年北京市的TSP和PM10仍不能达到国家二级标准。在今后几年内降低颗粒物的污染是北京市大气污染控制工作的首要任务。     

皂素生产废水的资源化综合利用实验

皂素生产废水是强酸性高浓度有机废水,富含淀粉水解后的糖类.据此特点,以皂素生产中的一次废水为原料,经中和处理后进行酒精发酵,使废水资源化.结果表明,采用工业氨水为中和剂,中和用量为5.20%(体积分数),发酵接种量为10%(体积分数),总发酵时间为60 h时,4 L废水可生产出95%的工业酒精120 mL.一次废水COD去除率达75%,后续废水量大大减少,具有明显的环境效益.经估算每生产lt工业酒精可处理4lt一次废水,与生产成本相比,具有明显的经济效益.     

Aggregated Versus Individual Land-Use Models: Modeling Spatial Autocorrelation to Increase Predictive Accuracy

The objective of this paper is to compare the predictive accuracy of individual and aggregated econometric models of land-use choices. We argue that modeling spatial autocorrelation is a comparative advantage of aggregated models due to the smaller number of observation and the linearity of the outcome. The question is whether modeling spatial autocorrelation in aggregated models is able to provide better predictions than individual ones. We consider a complete partition of space with four land-use classes: arable, pasture, forest, and urban. We estimate and compare the predictive accuracies of individual models at the plot level (514,074 observations) and of aggregated models at a regular 12 × 12 km grid level (3,767 observations). Our results show that modeling spatial autocorrelation allows to obtain more accurate predictions at the aggregated level when the appropriate predictors are used.