大气降水化学的统计学分析——以浙江省金华市为例

运用相关分析、因子分析和聚类分析等统计学方法,对2004-2005年间浙江省金华市的大气降水化学组成和分布特征进行了分析.结果表明,SO2-4,NH 4,Ca2 ,NO-3和H 是降水的主要离子,降水的pH值、电导率及离子组分均呈明显的正偏态分布,降水样品以低离子含量的样本为主.降水中水溶性离子主要分为4类,SO2-4,NH 4,NO-3,Ca2 和F-主要来自人为活动的贡献,K 和Mg2 主要来自土壤、沙尘等地壳来源,Na 和Cl-属于典型的海盐性成分,H 则反映了各种离子中和作用对降水酸度的综合影响.     

有有效时间约束的最大流问题及其算法

交通运输在抗震救灾中起着非常重要的作用,无论是运输量的多少或是时间的及时与否,都直接影响着救灾的效果.而前人的单发点最短路径算法,难以满足救灾中多处救援物资及时到达和救援物资量上的需要.本文设计了确定救援站点(发点)的快速搜索程序,并在此基础上将单发点的救援路线问题扩展为多发点问题.同时考虑各条路段的最大运输量,使得出的紧急救援路线,不仅能满足救援物资的及时到达,同时又能满足对救援物资等运输量上的需求.     

昆钢煤气系统的经济安全性分析与优化

从安全运行和经济运行两方面论述了昆钢煤气系统中存在的问题，针对存在问题提出解决措施及建议。     

GIS支持下的小尺度土地驱动力研究--以宜兴市湖滏小流域为例

为了能够建立土地演化的模拟模型，在ARCINFO中的GRID模块的支持下，对宜兴市湖滏小流域的土地驱动力进行了探讨，建立了以像元为单位的属性数据库，并随机选取了600个样点。分析则采用了LOGISTIC模型，探讨了社会经济因子与土地类型转移概率间的关系，揭示了任意两个土地类型相互转换的驱动力及整个地区的土地变化驱动力。最后讨论了该模型模拟预测时的局限性，说明其不是合适的模拟模型，而仅是分析土地驱动力较好工具。这种分析是进一步用概率方式逐个模拟地块(patch)演化的基础，因而具有一定的现实意义。     

驾驶员自身因素对限速标志识别能力的影响分析

以研究城市道路限速标志下驾驶行为的变化为主要目的,基于认知心理学知识,采用实地观测和问卷调查等手段,研究了驾驶员经过限速标志时的心理及反应过程。依据认知工效学中的注意和记忆等机制对驾驶员的限速标志认知过程进行了解析;从驾驶员自身角度分析了影响驾驶员识别限速标志的主要因素;利用因子分析方法对调查数据和调查项目进行统计分析;最终提取了影响驾驶员识别限速标志的6个自身因素为主因子,作为限速标志对驾驶行为影响较大的因素。该研究结果可为城市道路限速标志的设计与设置提供科学依据。     

Determination of the maximum effective burning velocity of dust–air mixtures in constant volume combustion

The reactivity of a combustible dust cloud is traditionally characterized by the so-called K_St value, defined as the maximum rate of pressure rise measured in constant volume explosion vessels, multiplied with the cube root of the vessel volume. The present paper explores the use of an alternative parameter, called the maximum effective burning velocity (u_eff,max), which also is derived from pressure–time histories obtained in constant volume explosion experiments. The proposed parameter describes the reactivity of fuel–air mixtures as a function of the dispersion-induced turbulence intensity. Procedures for estimating u_eff,max from tests in both spherical and cylindrical explosion vessels are outlined, and examples of calculated values for various fuel–air mixtures in closed vessels of different sizes and shapes are presented. Tested fuels include a mixture of 7.5% methane in air, and suspensions of 500 g/m³ cornstarch in air and 500 g/m³ coal dust in air. Three different test vessels have been used: a 20-l spherical vessel and two cylindrical vessels, 7 and 22 l. The results show that the estimated maximum effective burning velocities are less apparatus dependent than the corresponding K_St values.     

核电厂运行人员可靠性研究中若干问题的分析

对已有人因可靠性分析模型进行归纳总结,结合核电厂运行人员可靠性研究实际,对人因分类、人因建模、数据采样及人因数据库完善等方面存在的问题进行分析,并提出可能的解决办法或研究方向:在人因分类方式上,要加强因素之间的细化程度,以降低评价的模糊性;在人因量化方面,要重点考虑其所依赖的HRA模型、数学依据、结果精确度等3个方面的影响;对待数据采集的问题,规范性数据采集平台的构建是确保数据一致性的关键措施,并有利于不同HRA模型之间接口相容性问题的解决;人因数据库管理系统的智能决策功能是研发设计的趋势。     

The Political Import of Intrinsic Objections to Genetically Engineered Food

Many people object to genetically engineerehd (GE) food because they believe that it is unnatural or that its creation amounts to playing God. These objections are often referred to as intrinsic objections, and they have been widely criticized in the agricultural bioethics literature as being unsound, incompatible with modern science, religious, inchoate, and based on emotion instead of reason. Many of their critics also argue that even if these objections did have some merit as ethicalobjections, their quasi-religious nature means that they are entirely irrelevant when interpreted aspolitical objections regarding what public policy ought to be. In this paper, we argue that this widespread view is false. Intrinsic objections have much more political import than has previously been recognized, and indeed the requirements of political liberalism and its associated idea of liberal neutrality, once properly understood, protect intrinsic objections from many of the most common objections. That is, policy-makers may not legitimately base public policy on grounds that are inconsistent with intrinsic objections, even when they believe those objections to be flawed in the ways mentioned above. This means that in the context of a political debate about GE food, the discussion should not center on the substantive merits of the intrinsic objections themselves but rather on the appropriate political norms for achieving democratically legitimate policy on issues that touch people’s deepest religious and moral beliefs.     

基于贝叶斯网络的人因可靠性评价

提出一种贝叶斯网络的人因可靠性评价(HRABN)方法,其中的每个因子对应于贝叶斯网络中的节点,该方法可对人因可靠性作定量分析和定性分析。在定性分析上,节点的因果关系(HRA中的因子关系)及需要改进的薄弱节点都直观地显示在层次图中;在定量分析方面,对节点因子后验概率的推断通过HRA中的先验信息(包含仿真数据、现场操作及专家知识等)和最新信息得到。如果人因可靠性贝叶斯网络中的每个节点的先验概率分布和后验概率分布都已知,模型的可信性就可通过贝叶斯因子进行定量验证。贝叶斯网络扩展性好,当有新的节点因子需要考虑时,只需要补充对应的节点;笔者的方法也能很好地应用在不同行业的HRA。