环境污染的国际转移与城乡转移

从广义上考察了环境污染的国际转移与城乡转移,包括可见的和不可见的污染转移。分析了污染转移的不同途径,从环境质量需求和个人贴现率两个方面分析了污染转移的经济机制,以此为基础,探讨了防止污染转移的对策。     

民航机组人员个体与组织匹配对安全绩效的影响——基于MOA模型的定性比较分析

人为因素成为当今航空飞行安全的最大隐患,针对人的安全科学管理至关重要.为进一步探索民航机组人员安全行为路径,寻求可能的行为管理切入点,将民航机组人员作为研究对象,以MOA模型(动机-机会-能力)为理论框架,应用模糊集定性比较分析方法,探究民航机组人员个体与组织两个层面的5个条件对员工安全绩效差异的多重并发复杂机制和因果...     

Divergence in sink contributions to population persistence

Population sinks present unique conservation challenges. The loss of individuals in sinks can compromise persistence; but conversely, sinks can improve viability by improving connectivity and facilitating the recolonization of vacant sources. To assess the contribution of sinks to regional population persistence of declining populations, we simulated source–sink dynamics for 3 very different endangered species: Black‐capped Vireos (Vireo atricapilla) at Fort Hood, Texas, Ord's kangaroo rats (Dipodomys ordii) in Alberta, and Northern Spotted Owls (Strix occidentalis caurina) in the northwestern United States. We used empirical data from these case studies to parameterize spatially explicit individual‐based models. We then used the models to quantify population abundance and persistence with and without long‐term sinks. The contributions of sink habitats varied widely. Sinks were detrimental, particularly when they functioned as strong sinks with few emigrants in declining populations (e.g., Alberta's Ord's kangaroo rat) and benign in robust populations (e.g., Black‐capped Vireos) when Brown‐headed Cowbird (Molothrus ater) parasitism was controlled. Sinks, including ecological traps, were also crucial in delaying declines when there were few sources (e.g., in Black‐capped Vireo populations with no Cowbird control). Sink contributions were also nuanced. For example, sinks that supported large, variable populations were subject to greater extinction risk (e.g., Northern Spotted Owls). In each of our case studies, new context‐dependent sinks emerged, underscoring the dynamic nature of sources and sinks and the need for frequent re‐assessment. Our results imply that management actions based on assumptions that sink habitats are generally harmful or helpful risk undermining conservation efforts for declining populations.     

Mineralogical characterization of airborne individual particulates in Beijing PM10

This work mainly focuses on the mineralogical study of particulate matter（PM10） in Beijing. Samples were collected on polycarbonate filter from April, 2002 to March, 2003 in Beijing urban area. Scanning electronic microscopy coupled with energy dispersive X-ray（SEM/EDX） was used to investigate individual mineral particles in Beijing PM10. 1454 individual mineral particulates from 48 samples were analysed by SEM/EDX. The results revealed that mineral particulates were complex and heterogeneous. 38 kinds of minerals in PM10 were identified. The clay minerals, of annual average percentage of 30.1%, were the main composition among the identified minerals, and illite/smectite was the main composition in clay minerals, reaching up to 35%. Annual average percentage of quartz, calcite, compound particulates, carbonates were 13.5%, 10.9%, 11.95%, 10.31%, respectively. Annual average percentage less than 10% were gypsum, feldspar, dolomite, and so on. Fluorite, apatite, halite, barite and chloridize zinc（ZnCl2） were firstly identified in Beijing PM10. Sulfurization was found on surface of mineral particles, suggested extensive atmospheric reaction in air during summer.     

加速遗传算法及其在环境模型参数估计中的应用

提出了遗传算法的一种改进方法－－加速遗传算法，分析了该算法控制参数的优化特性，总结了这些参数的简便设置技术，并给出了它在环境模型参数估计中的几个应用实例。     

两种制度下公共资源长期耗用之比较

丁和张维迎对“公共地悲剧”的论述,是以参与耗用公共资源的人数不变为假定的。但是,有些资源即使在长期中也无法改变其公共资源的属性,这使得耗用这类资源的人数在长期中会发生变化。只要有超额利润,就会有更多的人参与耗用该资源;反之,则会有人退出。通过构建数学模型,探讨了长期中两种不同的制度安排（个体理性与集体理性）下,人们耗用这种无进入壁垒公共资源的均衡情况的差异。结果显示,集体理性可以使该资源的耗用速度减慢,但是会导致生产效率低下、社会福利减少;而个体理性下资源的消耗速度更快,但可以达到提高生产效率、增加社会福利的效果。进一步认为,解决资源短缺问题,制度只能是权宜之计,技术才是根本出路。     

城市雾天单个矿物颗粒物理和化学特征

应用场发射扫描电镜(FESEM)和带能谱的扫描电镜(SEM-EDX)对北京冬季雾天和正常天气下收集的4个样品进行研究.雾天中矿物颗粒的数量-粒度分布的峰值出现在0.1～0.3 μm和1～2.5 μm之间,并且发现雾天出现的二次矿物颗粒的数量百分含量(4.67%)高于正常天气条件(0.12%).单个矿物颗粒的EDX能谱显示,雾天和正常天气中单个矿物颗粒的主要化学成分有一定的差别,尤其是S元素.矿物颗粒分为9种不同类型:"富Si"、"富Ca"、"富S"、"富Fe""富Mg"、"富Al"、"富Ti"、"富K"和"富Cl",其中雾天"富Ca"中55%的颗粒含有Ca(50%±1.2%)和S(37%±1.6%),"富S"中72%的颗粒含有S(44%±1.5%)和Ca(33%±2%),说明了雾天中绝大部富集S的颗粒物中同时富集Ca,这在一定程度上说明了北京市大气中这些含Ca的碱性矿物对雾水酸性有一定的缓冲作用.雾天样品中S/Ca的平均比值为6.11,如果以冬季正常天气条件下S/Ca的均值0.73为背景值,雾天中S/Ca的比值是冬季正常天气的8倍,可见雾天中颗粒物表面的硫化现象相当严重,同时也显示出雾天SO2向硫酸盐的转化率比较高.     

Determining the age of cyclomorphic rodents: Functional-ontogenetic determination,ecological aspects

Functional-ontogenetic determination of age-dependent dental changes (ADCs) in voles has been demonstrated. The relationship between ADCs and the functional state of animals has been analyzed. A scheme and a table for determining individual chronological and biological ages in the bank vole (Clethrionomys glareolus Sch.) are proposed, which markedly improve the accuracy of results. Cases of rodent maturation and breeding in winter are considered.     

喀斯特坡耕地浅层地下孔(裂)隙发育过程中径流产污特征

降雨径流产生的非点源污染是地下水污染的重要来源,喀斯特坡耕地浅层地下孔(裂)隙养分流失是造成该地区地下水污染的关键因素.通过模拟喀斯特坡耕地地下孔(裂)隙特征,采用人工模拟降雨和室内分析相结合的方法,研究浅层地下孔(裂)隙发育过程中降雨径流产污特征.结果表明:喀斯特坡耕地地下径流产污是一个极其复杂的过程,微度(1%)孔(裂)隙发育的坡耕地径流全氮、全磷和全钾流失量随雨强变化不明显,全氮和全磷流失量均在70 mm·h-1雨强达到最大值;轻度(3%)孔(裂)隙发育的坡耕地全氮、全磷流失量在雨强50 mm·h-1时达到最大值;中度(5%)孔(裂)隙发育的坡耕地全氮、全磷、全钾流失量则在雨强为90 mm·h-1时达到最大值;各孔(裂)隙发育条件下的全氮、全磷、全钾养分流失量对坡度的响应不明显,轻度发育下的全氮和全磷流失量最大,在中度发育条件下,坡耕地土壤中全钾流失总量最大;不同雨强、坡度条件下的地下径流全氮、全磷和全钾次产污模数随地下孔(裂)隙度变化亦不明显,其中全氮次产污模数在4.38~58.72 mg·h-1·m-2,全磷在0.16~3.15 mg·h-1·m-2,全钾在0.16~3.03 mg·h-1·m-2范围变化.     

天然气输送管道泄漏事故危害定量分析

针对某天然气工程中高压输送管道可能发生的天然气泄漏的爆炸危险性进行分析.利用质量流速模型计算出泄漏流量.根据泄漏流量和天然气的燃烧下限浓度,通过高斯扩散模式定量计算在大气为中性,风速为5 m/s,且位于市区的条件下,天然气在大气中的轴向、径向和切向的扩散距离,从而计算该天然气-空气混合云团的体积.对该体积预混云团的爆炸危害进行评估,计算形成蒸气云爆炸的参数,并应用Mat lab软件计算出该管道泄漏引起蒸气云爆炸事故的个人风险曲线,其结果可为新管线的规划、建设及现有管线的调整提供决策依据.