供水管网系统地震易损性风险评估

供水管网易损性风险评估就是通过识别和分析系统的易损性,找出管网中相对比较薄弱的部分,为确定安全策略和采取控制措施提供理论依据。借鉴网络脆弱性评估理论和方法,基于震后供水管网的连通性分析和水力分析结果,采用分层的分析方法,以管网的拓扑位置和节点服务特性作为影响管网易损性的因素,分配给各节点一定的权值,计算其易损性指标,采用定性与定量相结合的方法评判其易损性程度。对一实际管网进行地震易损性风险评估,说明了该方法的有效性与合理性。     

中国二元经济中水资源流转模式研究

农业用水效率低下及水资源在工农业两部门间的结构性短缺将成为我国经济转型中面临的主要资源问题之一。如何优化配置水资源,实现工农业两部门的"双赢"是经济发展面临的一个重要课题。文章基于刘易斯-费-拉尼斯模型对二元经济结构体制下水资源流转过程进行系统性的经济学阐述,进而得出水资源在工农业两部门中的流转是从无限供给状态到体现稀缺性的过程。并结合1949-2009年中国水资源的利用情况,对中国水资源在两部门经济中的流转进行了阶段识别和趋势研究,即"余水"流转、"低效水"流转和"竞争性用水"流转,从而为水资源流转的实际操作提供了学理性解释,并据此提出通过建设引水工程基础设施、完善用水额度和税费标准法律规范,健全水资源流转的农业补偿机制和加强农业生产部门节水意识宣传,以完善我国水资源流转制度的相应对策建议。     

Dose transfer of Bacillus thuringiensis from cabbage to the diamondback moth: A graphical simulator

Abstract

The application of agrichemicals is a highly inefficient process and one of the main causes of the environmental and health risks currently associated with pesticide usage. Efforts to mitigate this inefficiency have largely been unsuccessful, due principally to the poor understanding of the processes involved in the spray application of pesticides, from atomization to biological effect. A generalized model of the application system for pesticides from atomization to biological result is described in this overview. The model allows the investigation of the biological consequences of altering the application parameters for the bacterial insecticide Bacillus thuringiensis when used against the diamondback moth (Plutella xylostella L.) with cabbage as the substrate. Parameters input into the model include the in‐flight droplet size frequency distribution of the spray cloud, spatial distribution of the deposit, spread and subsequent environmental degradation of the deposit, and behavioral and toxicological effects.

It is hoped that such a modelling approach can afford insights into the application process, and, through a better understanding of the inefficient but still highly effective hydraulic application systems used worldwide, reduce that inefficiency to tolerable levels.     

The growth and Cu and Zn uptake of pakchois (Brassica chinesis L.) in an acidic soil as affected by chicken or pig manure

In a pot experiment, pig manure (PM) and chicken manure (CM) were applied to an acidic soil at application rates of 2%, 4% and 8% (W/W) to evaluate their effects on the growth, Cu and Zn uptake and transfer of five cultivars of pakchoi (Brassica chinesis L.). The results showed that alkaline manures significantly increased the biomass of pakchois, and also pH and electrical conductivity of the soil. Both 0.01 M CaCl₂ and 1.0 M NH₄NO₃ salt solutions predict the Zn transfer from soil to pakchois well, but not for Cu. For the cultivar Siyueman, the transfer factors of Cu (or Zn) in the PM treatments were higher than that in the CM treatments. In our experiment the Cu and Zn concentrations in pakchois did not exceed the Chinese Food Hygiene Standard, but more attention should be paid to heavy metals risk on pakchois at lower soil pH and salt impairment by manures application.     

Relevant parameters for assessing the environmental impact of some pyridinium, ammonium and pyrrolidinium based ionic liquids

Several physico-chemical properties relevant to determine the environmental impact of ionic liquids - aqueous solubility, octanol/water partition coefficient, chromatographically derived lipophilicity and infinite dilution diffusion coefficients in water - were measured in ionic liquids based on pyridinium, ammonium and pyrrolidinium cations with bis(trifluoromethylsulfonyl)imide anions. The influence of the presence of hydroxyl or ester groups in the physico-chemical properties of these liquids was checked. It appeared that the presence of functional oxygenated moieties reduces the lipophilicity of ionic liquids and so decreases the risk of bioaccumulation in environment.     

我国环境技术转移模式与运行保障机制的研究

全面阐述了我国环境技术成果转化推广机制建设取得的积极进展,以及当前存在的困难和问题;基于环境技术转移体制机制的内涵,提出了环境技术转化转移机制建设应遵循的四项原则;论述了环境技术转化转移模式选择和六项保障环境技术转化转移能动健康运行的保障机制性措施。     

潞城市大气PM_（10）中化学元素分布特征

利用ICP-AES分析了潞城市采暖期和非采暖期4个不同功能区PM10样品中16种化学元素,对不同元素的时空分布特征进行了研究,并采用富集因子和主成分分析初步研究了潞城市PM10中元素的主要来源。结果表明,潞城市PM10中重金属污染较为严重,且各元素在采暖期的平均浓度均明显高于非采暖期。PM10中Ca、V、Cr、As、Ni、Mn、Cu、Zn、Al和Pb的富集因子EF〉10,主要来源于人为污染;而Na、Mg、Si、Fe和K的EF〈10,除部分来自人为活动外,主要来自土壤风沙等自然来源。主成分分析结果显示,潞城市PM10中元素的主要来源按贡献率大小依次为：煤烟尘和工业粉尘50.39%,自然源34.37%和机动车尾气15.24%。     

医疗废物高温蒸气杀菌工艺中质热传递模型

医疗废物高温蒸气灭菌工艺中,如何使蒸气充分渗透到医疗废物内部是决定杀菌效果的关键。结合实际的操作工艺,以单片物料作为研究对象,将其视为多孔介质,从多孔物料传质传热的基本理论出发,建立了医疗废物内部传质传热数学模型,给出了其解析解,并通过实验验证了所建模型的合理性。     

农村集体建设用地流转对资源配置的影响评析

为实现土地资源优化配置,本文系统地比较分析了农村集体建设用地流转前后的资源配置状况,以确定配置方式的有效性或选择合理的调控制度.结果表明,与土地征收相比,集体建设用地流转有助于优化资源配置.但在有无相应的制度安排或制度如何安排以及利益主体行为趋向的影响下,集体建设用地流转对实现资源优化配置不一定更有效.如果缺乏合理规范或有效的制度安排,集体建设用地流转市场功能仍然是微弱的或将带来资源配置负效应.要实现土地资源最优配置,就必须在把握集体建设用地流转系统内部结构及外部环境对资源配置影响机理的基础上,对集体建设用地流转进行优化调控.本文提出如下政策建议:完善农村集体建设用地流转立法建设,为流转提供法律支持;深化集体土地产权制度建设,明确集体土地产权主体及其产权权能;加强农村集体建设用地流转市场培育与政府管制制度的系统建设和改革,实现市场机制和政府干预的耦合;转变政府职能,多方面保障政府行为规范化.     

农民非农收入与农村土地流转关系的协整分析——以江苏省南京市为例

农村土地流转是提高土地利用率、实现土地规模化、加快农村剩余劳动力转移的重要方式.尤其是在党的十七届三中全会<决定>中明确提出要加快农村土地流转,发展适度规模经营.而农地流转能否增加农民非农收入、缩小收入差距是农地流转过程中必须回答的现实问题.本文以江苏省南京市调查数据为例,采用协整方法对农民非农收入影响农地流转的长期均衡关系及其作用机制进行了探讨.研究结果表明:农民非农收入与农地流转之间存在着长期均衡关系,但短期却存在波动.同时,农民非农收入水平与农地流转之间存在着双向因果关系,而且早期农地流转对农民非农收入的影响程度较弱.在此基础上,本文从加快发展非农产业,提供农民非农收入水平;大力发展农村职业教育,提高农民文化水平与素质;培育完善农地流转和农村劳动力就业市场等方面提出了对策建议.