臭氧二级传递标准量值传递技术

臭氧(O_3)二级传递标准对O_3三级传递标准进行量值传递,开展了对分析类型、发生类型等不同类型O_3三级传递标准的量值传递实验。分析类型O_3三级传递标准6组校准斜率的相对标准偏差Sm为0.19%、截距的标准偏差SI为0.25 nmol/mol;发生类型O_3三级传递标准6组校准的Sm为0.67%、SI为0.20 nmol/mol,均符合美国环保局O_3二级传递标准量值传递的评价指标:6组多点校准斜率的相对标准偏差Sm≤3.7%,截距的标准偏差SI≤1.5 nmol/mol。进一步对分析类型、发生类型O_3三级传递标准分别进行了6个月的量值传递时间稳定性考察,O_3三级传递标准新的斜率与最近6组斜率均值的比值为0.965~1.037,且新计算的斜率的相对标准偏差Sm为0.37%~1.87%,截距的标准偏差SI为0.20~0.52 nmol/mol,均符合美国环保局量值传递评价指标的要求,建议至少每6个月采用O_3二级传递标准开展一次量值传递。     

厌氧折流板调节池预处理垃圾转运站压滤液的中试研究

建立了中试规模的厌氧折流板调节池,用于转运站垃圾压滤液的现场预处理。转运站垃圾压滤液具有高有机污染物浓度、水质变化剧烈和pH值较低等特点,当进水COD浓度为50 000 mg/L～80 000 mg/L,厌氧折流板反应器能稳定实现出水COD=25 000 mg/L左右,总氮去除率30%～40%,总磷去除率70%,抗冲击能力和低pH值进水运行稳定性良好。厌氧折流板调节池发生酸化后,综合采用了多种措施加以调控。     

中国财产保险业巨灾损失赔付能力实证分析

商业保险是社会化巨灾风险分散机制的重要组成部分,要在中国现阶段巨灾事件频发的复杂环境中构建合理的损失分摊机制,不能不考虑以损失补偿为主要功能的财产保险业应对巨灾损失的能力。在Cummins、Doherty和Anita的保险赔付能力度量模型框架及改进后的损失对数正态分布假设下,引入1998～2008年中国财产保险业经营数据,对2009年初时点上在中国大陆经营财产保险业务的39家财产保险公司及全行业巨灾损失赔付能力进行了实证分析。结果显示,由于全行业资本与盈余的低水平以及再保险市场发展的严重滞后,在1 200亿到2 000亿元的损失区间内,中国财产保险业的赔付能力缺口在26.8亿到815.6亿元之间,且缺口增长速度大于损失增长速度。通过与2008年初的赔付能力实证分析结果对比发现,灾害频发的2008年客观上显著降低了中国财产保险行业应对极端损失的能力。度量结果从实证基础上昭示了政府大力扶持和参与巨灾保险体系建设的必要性和紧迫性。     

Dissolution kinetics of sub-millimeter Composition B detonation residues: role of particle size and particle wetting

The dissolution of the 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) from microscale particles (<250 μm) of the explosive formulation Composition B was examined and compared to dissolution from macroscopic particles (>0.5 mm). The dissolution of explosives from detonation soot was also examined. The measured mass transfer coefficients for the microscale particles were one to two orders of magnitude greater than the macroscopic particles. When normalized to particle surface area, mass transfer coefficients of microscale and macroscale particles were similar, indicating that the bulk dissolution processes were similar throughout the examined size range. However, an inverse relationship was observed between the particle diameter and the RDX:TNT mass transfer rate coefficient ratio for dry-attritted particles, which suggests that RDX may be more readily dissolved (relative to TNT) in microscale particles compared to macroscale particles. Aqueous weathering of larger Composition B residues generated particles that possessed mass transfer coefficients that were on the order of 5- to 20-fold higher than dry-attritted particles of all sizes, even when normalized to particle surface area. These aqueous weathered particles also possessed a fourfold lower absolute zeta-potential than dry-attritted particles, which is indicative that they were less hydrophobic (and hence, more wettable) than dry-attritted particles. The increased wettability of these particles provides a plausible explanation for the observed enhanced dissolution. The wetting history and the processes by which particles are produced (e.g., dry physical attrition vs. aqueous weathering) of Composition B residues should be considered when calculating mass transfer rates for fate and transport modeling.     

堤防工程综合安全模型和风险评价体系研究及应用

为获得荆南长江干堤的安全特性,在层次分析法及模糊一致理论的基础上,考虑堤防工程水、土两相系材料的特点,建立了模糊综合评判系统结构模型。通过正态型模糊隶属函数,结合两种权值理论实现了对堤防工程的安全综合评判。在模糊综合评判结论的基础上,结合模式识别的间接方法,提出了广义多维加权模糊识别模型,实现了对典型堤身段的安全模式识别,并对模型指标体系作了敏感性分析。所得成果比较全面地反映了干堤在复杂运行条件下的综合安全特性,对指导工程现场管理与监测有现实意义。对于复杂堤防系统,模糊综合评判是实现全面风险分析的有效手段,而广义多维加权模糊识别模型可以为工程安全决策提供有力依据。     

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。     

劳动节约型技术进步下的就业转移

在人均GDP可比水平下,我国农业就业份额远高于同一发展阶段的日本、韩国、台湾省,年均农业就业份额下降速度及人均GDP每增长1 000 GK$农业就业份额下降速度均落后于日本、韩国和台湾省。这表明我国农业就业非农化转移相当缓慢,大大滞后于经济发展。延续发展经济学假设,结合新古典理论分析,表明影响农业就业转移的因素包括:资本增长率、创新强度、技术进步的劳动节约偏向和边际劳动产出递减的倾向。利用我国非农产业数据进行实证检验,表明技术进步的劳动节约偏向是就业转移滞后的深层次原因。     

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.     

不同进水条件下ASM1模型参数的灵敏度分析

编制了BSM1的仿真程序,并分析了不同进水条件下ASM1模型的16个参数对BSM1出水COD、TN、NH4+-N、NO3--N灵敏度的影响.结果表明,9个参数的灵敏度在规定的划分范围内没有区别,7个参数在不同进水条件下差别较明显;各参数灵敏度的变化规律,与出水的NH4+-N及NO3--N浓度变化有一定相关性;灵敏度变化与ASM1模型速率方程中的开关函数有关.研究不同进水条件下模型参数的灵敏度,有助于提高污水处理仿真计算的准确性.