Enhancement of solar-driven photocatalytic activity of oxygen vacancy-rich Bi/BiOBr/Sr2LaF7:Yb3+,Er3+ composites through synergetic strategy of upconversion function and plasmonic effect

For better use of solar energy,the development of efficient broadband photocatalyst has attracted extraordinary attention.In this study,a ternary composite consisting of Sr₂ LaF₇:Yb³⁺,Er³⁺ upconversion(UC) nanocrystals and Bi nanoparticles loaded BiOBr nanosheets with oxygen vacancies(OVs,SLFBB) was designed and synthesized by multistep solvent-thermal method.Mechanisms of in-situ formation of Bi nanoparticles and OVs in BiOBr/Sr₂ LaF_7<...     

武钢炼铁厂4号高炉出铁场除尘综述

介绍了武钢炼铁厂4号高炉出铁场烟尘捕集的重要性,分析了高炉出铁口烟尘捕集采用布袋除尘器方式,指出了其发展趋势。     

Nature Reserve and Ecotourism Development in China＇s Wuzhishan Mountain Region

As the protected areas of land and coastal environment, nature reserves are designed to address how to reconcile the conservation of biodiversity, the quest for economic and social development and the maintenance of cultural values. This paper establishes a framework for nature reserve development that seeks to incorporate ecotourism into its strategies. The overall purpose was to identify the information needs required for a comprehensive nature reserve that incorporates ecotourism related values. It also illustrates the utility of this framework in the context of the Wuzhishan Mountain Region of China. A literature review, the first phase of a visionary strategy and a subsequent gap analysis for available management information were undertaken in order to achieve this paper＇s purpose. Finally, recommendations axe pre-sented for integrating ecotourism into nature reserve development in the Wuzhishan Mountain Region.     

试论人口—资源—环境与经济的协调发展

人口、资源、环境与经济之间是相互制约又相互依存的动态关系,四者的协调发展包括“有限协调发展”和“完全协调发展”两个层次,其实质是弱化、消除其间的消极关系和消极影响,同时充分利用和促进其间的积极关系,实现四者之间的良性循环。我国作为一个发展中的人口大国,“协调发展战略”应以不影响长远的持续发展为前提,把经济发展置于中心位置,强调在发展经济的过程中要同时解决人口、资源与环境问题。     

ECONOMIC VALUATION OF RIPARIAN BUFFER AND OPEN SPACE IN A SUBURBAN WATERSHED1

Abstract: This study evaluates the economic value of riparian buffers and open space in a suburban watershed through two nonmarket valuation methods. A contingent valuation survey was implemented in the Dardenne Creek watershed, a suburban watershed of the St. Louis metropolitan area in Missouri, to evaluate the residents' perceptions of and willingness to pay (WTP) for adopting riparian buffers and preserving farmland in a hypothetical real estate market. A hedonic pricing model based on actual sale prices of homes in the watershed was applied to estimate the market value of open space and other environmental conditions such as flood zone and stream proximity in the study area. The results showed that residents' WTP was consistent with the economic values of open space and proximity to streams embedded in existing home prices. Through a better understanding of residents' perceptions and values, riparian buffer and open space programs can be designed and promoted to achieve greater implementation success and environmental benefit.     

PHYSICAL DETERMINANTS OF ECONOMIC VALUE OF RIPARIAN BUFFERS IN AN AGRICULTURAL WATERSHED1

ABSTRACT: Economic values of riparian buffers in a watershed are evaluated by the changes in the net economic return for farming with and without riparian buffers when achieving the same water quality objectives. The simulated water quality impacts of alternative farming systems using SWAT and experimental data for riparian buffers are used in a mathematical optimization model to estimate net economic return for farming subject to a water quality objective. Physical characteristics such as stream length, channel slope, average land slope, cropland percentage and several soil attributes are identified in the watershed using ARC/INFO GIS. A regression model is then used to evaluate the impacts of these physical characteristics on the estimated economic values of buffers. The study is conducted in Goodwater Creek watershed, Missouri. The results show the estimated economic value of buffers is significantly affected by some soil properties, stream length, and cropland percentage in watershed and can be used to improve the effectiveness of riparian buffers at watershed and regional levels.     

固定床PVC燃烧脱氯的机理和试验

研究垃圾组分PVC在焚烧过程中HCl的排放和脱除特性的实验在准等温、电加热的水平石英管反应器中进行.随着床温从700℃升高到900℃,HCl的转化率从82.5%平缓增加到88.3%,而过量空气系数的增加促使部分HCl转化为C1₂(1.9%～4.5%)的形式存在.钙基吸收剂CaCO₃,Ca(OH)₂,Ca(CH₃COO)₂对HCl的脱除效率高达68%～79%,而镁基吸收剂的脱氯效率却低于3%.小的吸收剂粒径、高的Ca/Cl比会促进脱氯效率的提高;烟气中CO₂和H₂O对脱氯效率的影响与它们在反应平衡中所起作用有关.高温下燃烧固氯机理反应的平衡常数的计算不仅诠释了实验结果,而且提供了脱氯吸收剂选择的依据.     

Determination of the dissociation constants of polyepoxysuccinic acid

The dissociation constants of polyepoxysuccinic acid (PESA) were investigated in this study. Based on the potentiometric titration and the BEST program, the dissociation constants of PESA were determined. Considering the complexity of the dissociation of PESA in aqueous solution, several models were constructed to simulate the dissociation process of PESA. By comparison, the dissociation constants of PESA were obtained with model 4. The species distribution of PESA in aqueous solution as a function of pH was also presented according to the experimental and calculation results. It showed that the H₂L model with five basic structure units to describe the dissociation of PESA was reasonable, and the relevant constants had less error and better matching between the experimental and calculation data. The corresponding values of pK _ai were 4.68 and 4.92, respectively, for H₂L at 35°C with ionic strength of 0.1 mol/L.     

恶臭嗅辨实验室的建立与发展研究

在使用国家推荐标准方法《空气质量恶臭的测定三点比较式臭袋法》（GB／T14675—93）测定恶臭气体浓度时,环节较多较繁杂,需要人工配气和人工嗅辨,监测过程中使用的器材、设备较多,因此容易引入误差。笔者建议从器材设备、实验室布局、嗅辨员选择等方面加强质量管理,通过严格执行相关标准,规范配气和嗅辨环节,加强质量控制等措施建立标准、规范的实验室,以提高监测结果的准确性。文章也简要介绍了国内外针对该方法监测过程中人工配气、人工嗅辨、人工计算的三大环节所开展的探索。