Condensation heat transfer with noncondensable gas for passive containment cooling of nuclear reactors

Noncondensable gases that come from the containment and the interaction of cladding and steam during a severe accident deteriorate a passive containment cooling system's performance by degrading the heat transfer capabilities of the condensers in passive containment cooling systems. This work contributes to the area of modeling condensation heat transfer with noncondensable gases in integral facilities. Previously existing correlations and models are for the through-flow of the mixture of steam and the noncondensable gases and this may not be applicable to passive containment cooling systems where there is no clear passage for the steam to escape. This work presents a condensation heat transfer model for the downward cocurrent flow of a steam/air mixture through a condenser tube, taking into account the atypical characteristics of the passive containment cooling system. An empirical model is developed that depends on the inlet conditions, including the mixture Reynolds number and noncondensable gas concentration.     

电信行业的经营分析系统研究

本文介绍了电信行业经营分析系统的作用、特点以及I3DSS的优点,提出了引入I3DSS的电信行业经营分析系统软件体系结构,并给出了基于该体系结构实现分析型应用的具体过程.国内某电信运营企业在建设其经营分析系统时已采用了本文的研究成果.实践证明,这些研究成果具有一定的推广应用价值.     

基于UWB定位系统硬件平台设计

为进一步研究基于UWB的无线定位技术,文中设计了一种基于UWB定位系统硬件平台。硬件平台基于模块式设计思路,选用STM32F405作为主控制器,通过SPI总线与DW1000射频芯片通信。UWB射频电路围绕DW1000设计布局,使用全向外置天线。硬件平台在通信方面设计使用GPRS无线通信模块并采用TOA定位方式,预留GPIO外设扩展接口。经制板测试,在视距空旷环境下最远通信距离为110m,在相同环境下100m测距均方根误差20.2cm,室内非视距环境中定位误差为20cm,满足室内高精度定位技术研究需求。     

ERP系统与商业智能的集成应用研究

结合ERP的特点，首先阐述了ERP的在决策支持上面的缺陷，而后从商业智能的理论出发。给出了BI与ERP集成的体系结构以及相应的系统解决方案。分别阐述了商业智能中的数据仓库、OLAP、数据挖掘等方面的功能以及具体应用方法，为企业更好的利用ERP资源、完成决策、提高企业竞争力提供了一种较为经济的方式。     

Health risk associated with dietary co-exposure to high levels of antimony and arsenic in the world's largest antimony mine area

Like arsenic (As), antimony (Sb) is known to be a genotoxic element in vitro and in vivo. Sb is now recognized as a global contaminant and has aroused the global concerns recently. However, knowledge is scarce concerning the transfer of Sb from the environment to humans and the related hazards to human health. In this pilot study, the health risk and main pathway of long-term human exposure to Sb and As for residents around Chinese Xikuangshan (XKS) Sb mine, the world's largest Sb mine, were evaluated by dietary exposure and hair accumulations survey. The concentrations and species of Sb and As in food samples (n = 209) from three main categories and six subcategories, and in hair samples (n = 89) were determined. Residents in the vicinity of XKS had an estimated dietary intake of Sb (554 μg/day) which was 1.5 times higher than the tolerable daily intake (TDI) (Sb, 360 μg/day), whereas their dietary intake of inorganic As (107 μg/day) was slightly lower than the provisional tolerable weekly intake (PTWI) of 15 μg/kg BW/week (equal to 129 μg As/day). Hair Sb and As concentrations (Sb, 15.7 mg/kg, DW; As, 3.99 mg/kg, DW) in XKS residents are both above the normal/toxic level. Rice, vegetables (especially leafy vegetable), drinking water, and meat/poultry were the dominant dietary intake sources of Sb for the residents. In contrast, rice was the uniquely dominant dietary intake source of As. Antimonate (Sb(V)) was the dominant Sb species in vegetables, drinking water and residents' hairs. This study highlighted the difference of exposure characteristics between Sb and As. The preliminary results suggested that dietary exposures to Sb, rather than As, was the dominant health risk to local residents. Nevertheless, the adverse effects of As levels on the health of residents still can not be ignored since the elevated As concentrations in human hair have reached the critical level for health risks. In addition, this pilot study did not consider the possible Sb and As combined effects.     

基于数据仓库的供电指标分析系统研究

分析了目前电力行业信息系统的现状,从必要性和可行性方面论证了建设电力行业数据仓库是信息化发展的必然。指出了数据仓库系统的建设是一个循环的建设体系,需要通过不断的用户需求分析对现有系统进行完善,并对供电企业的数据仓库建设提出了建议。     

一个企业生产经营决策支持系统研究

本文以一个钢丝绳生产企业的生产经营为背景,建立了以生产经营优化模型和调整系统为基础,以数据仓库为核心的生产经营决策支持系统并对其进行了研究。该系统为企业不同层次的决策者提供了科学的辅助决策方案,为企业获得满意的经济效益奠定了基础。     

新型捕收剂在缅甸某锡矿浮选中的应用

针对缅甸某含锡3.80%的锡矿石进行了浮选工艺试验研究。在磨矿细度为-74 μm粒级占74.20%,调整剂硫酸铵用量4 000 g/t、捕收剂DW271用量1 800 g/t、辅助捕收剂P86用量100 g/t条件下,经一粗二扫二精闭路浮选试验获得了锡精矿品位42.80%、锡回收率89.09%。     

基于改进蚁群算法的数据仓库多连接查询优化

传统蚁群算法在解决数据仓库查询优化问题时存在过早收敛、收敛速度慢的缺点。为此,对传统蚁群算法进行改进,将伪随机状态转移规则引入最大最小蚁群系统,在每次迭代结束后进行迭代局部搜索。实验结果表明,改进算法在多表连接查询优化中具有较快的收敛速度,能提高最优解的质量。     

基于KW、MW及DW的决策支持系统架构研究

SDSS是较为先进的决策支持系统，但由于其模型库中的模型固定不变，因此在实际应用中具有一定的局限性。提出了集成数据仓库DW、知识仓库KW和模型仓库MW作为底部架构的体系结构，能有效解决这一问题。该架构简化了模型获得和编码任务，增强了决策的有效性和智能性，提高了决策效率。