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排序方式: 共有491条查询结果,搜索用时 27 毫秒
421.
Yongming Ju Jianming Hong Xiuyu Zhang Zhencheng Xu Dongyang Wei Yanhong Sang Xiaohang Fang Jiande Fang Zhenxing Wang 《环境科学学报(英文版)》2012,24(12):2180-2190
Sulfated BiWO (SBiWO) was synthesized by an impregnation method to enhance the visible-light-driven photoactivities of BiWO (BiWO). The characterization results verified that sulfate anion mainly anchored on the catalyst surface greatly extended the visible-light-responsive range without destroying the crystal lattice. Moreover, the SBiWO-based photoactivities were evaluated with the removal of Malachite Green (MG) under UV-Vis irradiation emitted from two microwave-powered electrodeless discharge lamps (MPEDL-2) and under visible light (λ > 420 nm). The results demonstrated that the kinetic constant was increased 2.25 times, varying from 0.1478 (BiWO) to 0.3328 min-1 (SBiWO-1). Similar results were also obtained for the visible light-driven reaction. Furthermore, radical scavengers such as t-butanol restricted the visible-light induced degradation of MG over BiWO and SBiWO-1. This indicated that the sulfating process increased the generation of reactive oxygen species, which was further verified by molecular probe with salicylic acid. Thus, more blue-shifting at λ = 618 nm was observed over SBiWO. On the basis of the above results, the photocatalytic mechanism over the sulfated catalyst was also discussed. 相似文献
422.
官金华 《中国环境管理干部学院学报》2013,(3):88-91
地方政府投融资平台在促进地方经济发展,推动城市化进程,应对国际金融危机等方面发挥了重要作用。但由于缺乏统一的管理,各地方政府投融资平台财务状况披露不公开、不透明,债务风险急剧扩大,引起了有关部门和专家学者的高度关注。各地方政府应将融资平台的各种信息,特别是债务情况,定期向主管部门报告,建立地方投融资平台信用评价方法,使得投融资平台朝着健康、良性的方向发展。 相似文献
423.
退耕还林工程对农户生产生活影响研究 总被引:1,自引:0,他引:1
研究退耕还林工程与农户的关系对于退耕还林后续问题解决,完善工程具有重要意义.该研究在准格尔旗多年农户调查的基础上,对该旗退耕还林工程初期(2002年)和后期(2010年)农户生产生活情况进行了对比研究,主要探讨了退耕还林工程对农户家庭结构、收入水平和结构的影响,以及农户对退耕还林态度、禁牧圈养态度变化和对退耕还林工程评价,最后分析了农户返耕决策.研究结果表明:受访农户平均年龄由2002年的35.02岁上升为2010年的45.32岁,年轻农户比重明显下降;户均人口从2002年的3.75人下降到2010年的2.8人.农户人均毛收入由2002年的1 332.03元增长为2010年的5447.77元;收入结构也由牧业为主转为外出务工为主;养羊农户比重明显减小,但户均规模有增大的趋势.农户依然高度支持退耕还林,但对退耕补贴的满意度下降,大部分依然赞成禁牧和圈养,但支持力度有不同程度的下降.农户将退耕地返耕可能性较小,且大部分受访农户还支持进一步退耕. 相似文献
424.
XIAODONG CHEN FRANK LUPI ANDRÉS VIÑA GUANGMING HE JIANGUO LIU 《Conservation biology》2010,24(6):1469-1478
Abstract: Ecosystem services are being protected and restored worldwide through payments for ecosystem services in which participants are paid to alter their land‐management approaches to benefit the environment. The efficiency of such investments depends on the design of the payment scheme. Land features have been used to measure the environmental benefits of and amount of payment for land enrollment in payment for ecosystem services schemes. Household characteristics of program participants, however, may also be important in the targeting of land for enrollment. We used the characteristics of households participating in China's Grain‐to‐Green program, and features of enrolled land to examine the targeting of land enrollment in that program in Wolong Nature Reserve. We compared levels of environmental benefits that can be obtained through cost‐effective targeting of land enrollment for different types of benefits under different payment schemes. The efficiency of investments in a discriminative payment scheme (payments differ according to opportunity costs, i.e., landholders’ costs of forgoing alternative uses of land) was substantially higher than in a flat payment scheme (same price paid to all participants). Both optimal targeting and suboptimal targeting of land enrollment for environmental benefits achieved substantially more environmental benefits than random selection of land for enrollment. Our results suggest that cost‐effective targeting of land through the use of discriminative conservation payments can substantially improve the efficiency of investments in the Grain‐to‐Green program and other payment for ecosystem services programs. 相似文献
425.
Effects of rapeseed residue on lead and cadmium availability and uptake by rice plants in heavy metal contaminated paddy soil 总被引:9,自引:0,他引:9
Yong Sik Ok Adel R.A. Usman Sang Soo LeeSamy A.M. Abd El-Azeem Bongsu Choi Yohey HashimotoJae E. Yang 《Chemosphere》2011,85(4):677-682
Rapeseed (Brassica napus L.) has been cultivated for biodiesel production worldwide. Winter rapeseed is commonly grown in the southern part of Korea under a rice-rapeseed double cropping system. In this study, a greenhouse pot experiment was conducted to assess the effects of rapeseed residue applied as a green manure alone or in combinations with mineral N fertilizer on Cd and Pb speciation in the contaminated paddy soil and their availability to rice plant (Oryza sativa L.). The changes in soil chemical and biological properties in response to the addition of rapeseed residue were also evaluated. Specifically, the following four treatments were evaluated: 100% mineral N fertilizer (N100) as a control, 70% mineral N fertilizer + rapeseed residue (N70 + R), 30% mineral N fertilizer + rapeseed residue (N30 + R) and rapeseed residue alone (R). The electrical conductivity and exchangeable cations of the rice paddy soil subjected to the R treatment or in combinations with mineral N fertilizer treatment, N70 + R and N30 + R, were higher than those in soils subjected to the N100 treatment. However, the soil pH value with the R treatment (pH 6.3) was lower than that with N100 treatment (pH 6.9). Use of rapeseed residue as a green manure led to an increase in soil organic matter (SOM) and enhanced the microbial populations in the soil. Sequential extraction also revealed that the addition of rapeseed residue decreased the easily accessible fraction of Cd by 5-14% and Pb by 30-39% through the transformation into less accessible fractions, thereby reducing metal availability to the rice plant. Overall, the incorporation of rapeseed residue into the metal contaminated rice paddy soils may sustain SOM, improve the soil chemical and biological properties, and decrease the heavy metal phytoavailability. 相似文献
426.
金融危机爆发以来,我国企业尤其是中小企业受到了严重影响,国家为了保证中小企业的健康发展,中央政府、各地政府及各级商业银行相继出台了多项措施,来帮助小企业融资。其中部分措施在执行过程中无形中增加了商业银行的中小企业信贷风险。结合当前的金融危机背景,通过分析国家出台的政策给商业银行带来的信贷风险,分别从不同角度就如何加强当前商业银行的信贷风险控制进行了研究。 相似文献
427.
Consumer pressure is usually considered as one of the major drivers for more environmental friendly products. During the last decade an increasing focus on public procurement has emerged as an important contributor to that pressure. In this paper we focus on the role of municipalities and counties in green public procurement. Based on surveys we investigate to what degree green public procurement is implemented in Norwegian municipalities and counties and which capabilities are critical for successful green procurement. We both investigate to what degree environmental information is requested in call for tenders and also to what degree the information is actually used in the final selection of supplier. The information gathered from the municipalities and counties is compared with information obtained from potential suppliers to see if suppliers and purchasers agree on the importance of environmental demands in the selection of suppliers. 相似文献
428.
William Hartley Nicholas M. Dickinson Nicholas W. Lepp 《Environmental pollution (Barking, Essex : 1987)》2009,157(10):2654-2662
Degraded land that is historically contaminated from different sources of industrial waste provides an opportunity for conversion to bioenergy fuel production and also to increase sequestration of carbon in soil through organic amendments. In pot experiments, As mobility was investigated in three different brownfield soils amended with green waste compost (GWC, 30% v/v) or biochar (BC, 20% v/v), planted with Miscanthus. Using GWC improved crop yield but had little effect on foliar As uptake, although the proportion of As transferred from roots to foliage differed considerably between the three soils. It also increased dissolved carbon concentrations in soil pore water that influenced Fe and As mobility. Effects of BC were less pronounced, but the impacts of both amendments on SOC, Fe, P and pH are likely to be critical in the context of As leaching to ground water. Growing Miscanthus had no measurable effect on As mobility. 相似文献
429.
Global changes such as climate change and demographic change next to a more diverse urban society and restricted municipal budgets represent significant challenges urban planning has to deal with today and in the near future. This viewpoint presents insights from urban planning on urban green and open space development and respective planning processes for the city of Berlin, Germany. An environmental development strategy – the Urban Landscape Strategy – is introduced and presented as a success story due to a number of reasons. These reasons include specific aspects related to strategy development, illustration and communication as well as the use of reference projects and implementation programs. Finally, the administrative structure which combines urban planning and green and open space planning in one joint department is shown to significantly contribute to positive planning processes for the entire city. 相似文献
430.
A method for assessing environmental risk: A case study of Green Bay,Lake Michigan,USA 总被引:4,自引:0,他引:4
Hallett J. Harris Robert B. Wenger Victoria A. Harris David S. Devault 《Environmental management》1994,18(2):295-306
The Science Advisory Board of the US Environmental Protection Agency has recommended that risk reduction strategies become
the centerpiece of environmental protection. The goal in developing such strategies is to identify opportunities for greatest
reduction of ecological risks. This is a perspective that is significantly more comprehensive than the traditional focus on
human health risks arising from environmental degradation. The identification of ecological risks upon which environmental
protection efforts should be focused requires an ecological risk assessment methodology that is based on anthropogenic stressors
affecting an ecosystem and a set of impaired use criteria. A methodology based on this concept is developed and discussed
in this article. The methodology requires that risk values be assigned to each ecosystem stressor-impaired use pair that reflect
the degree to which the given stressor contributes to ecosystem risk as measured by the given impaired use criterion. Once
these data are available, mathematical analyses based on concepts from fuzzy set theory are performed to obtain a ranking
of ecosystem stressors. The methodology has been tested by applying it to a case study involving Green Bay of Lake Michigan.
A workshop was held in which 11 persons with extensive knowledge of the Green Bay ecosystem determined risk values through
a group-consensus process. The analytical portion of the methodology was then used to rank the ecosystem risks (stressors)
from several perspectives, including prevention management and remediation management. The overall conclusion of the workshop
participants was that the fuzzy set decision model is a useful and effective methodology for differentiating environmental
risk. 相似文献