SCS G2004在三峡水电站土石方工程量计算中的应用

主要介绍了SCS G2004土石方工程量计算模块的结构、操作流程以及土石方工程量二次处理、允许超挖量的计算方法以及在三峡工程中的具体应用,对读者和同行在实际工作中具有参考应用价值。     

Design evaluation of emergency core cooling systems using Axiomatic Design

In designing nuclear power plants (NPPs), the evaluation of safety is one of the important issues. As a measure for evaluating safety, this paper proposes a methodology to examine the design process of emergency core cooling systems (ECCSs) in NPPs using Axiomatic Design (AD). This is particularly important for identifying vulnerabilities and creating solutions. Korean Advanced Power Reactor 1400 MWe (APR1400) adopted the ECCS, which was improved to meet the stronger safety regulations than that of the current Optimized Power Reactor 1000 MWe (OPR1000). To improve the performance and safety of the ECCS, the various design strategies such as independency or redundancy were implemented, and their effectiveness was confirmed by calculating core damage frequency. We suggest an alternative viewpoint of evaluating the deployment of design strategies in terms of AD methodology. AD suggests two design principles and the visualization tools for organizing design process. The important benefit of AD is that it is capable of providing suitable priorities for deploying design strategies. The reverse engineering driven by AD has been able to show that the design process of the ECCS of APR1400 was improved in comparison to that of OPR1000 from the viewpoint of the coordination of design strategies.     

A MEMS device for <Emphasis Type="Italic">in-situ</Emphasis> TEM test of SCS nanobeam

In-situ tensile testing in TEM (transmission electron microscopy) is a useful tool for studying mechanical properties of nano-structures because it can provide quantitative information on sample deformation at atomic scale. To facilitate in-situ TEM tensile tests of SCS (single crystal silicon) nanobeam, a MEMS tensile-testing chip was designed and fabricated. The chip was fabricated by means of bulk micromachining and wafer bonding techniques. An SCS nanobeam, a comb drive actuator, a force sensor beam and an electron beam window were integrated into the chip. With the on-chip comb-drive-actuator stretching the nanobeam and in-situ TEM observation, tensile test on a 90 nm-thick nanobeam was performed and the strain-stress relationship was obtained. The Young’s modulus was fitted to be 161 GPa and did not show the size effect. Supported by the National Basic Research (973 Program) (Grant No. 2006CB300406)     

An optimized technique for reliability analysis of safety‐critical systems: A case study of nuclear power plant

Stochastic models are extensively used in quantifying the reliability of safety critical systems. These models use the state‐space model for reliability quantification. Markov chain is comprehensively used in describing a sequence of possible events of any system in which the probability of each event depends only on the state attained in the previous event. Markov chains are convenient to model the software system of the SCS with the help of Petri Nets, a directed bipartite graph widely used for the verification and validation of real‐time systems. However, the stochastic model suffers from the state‐space explosion problem. In this paper, we proposed a technique for reliability analysis of safety critical systems, excavating into the coherent optimization of Markov chain. The approach has been validated on 17 safety critical systems of nuclear power plants.     

昆明市主城区土地利用变化对地表径流的影响

为探究昆明市主城区土地利用变化对地表径流的影响,采用昆明市主城区5个气象站点1986、1995、2000、2007、2014年的逐日降雨及其土地利用类型数据,通过率定后的SCS模型模拟昆明市主城区地表径流。结果表明,率定后的SCS模型适合昆明市主城区,模拟平均相对误差小于15%;1986~2014年水田、草地、灌木林和疏林地面积大幅减少,主要转化为城市建设用地和有林地,渗透比例由82%减至57%,提高了昆明市主城区雨水产流能力;地表径流量随渗透比例减少呈增加趋势,尤其表现在昆明市主城区东部和南部地区。     

亚复杂系统中动力学干预规则挖掘技术研究进展

亚复杂系统干预规则挖掘是数据挖掘领域的新内容。综述了亚复杂系统干预规则研究背景和典型问题,通过实例,描述了干预规则挖掘领域一些基本概念和术语,如干预相关度、传递相关度、干预分型和干预代数等;介绍了在亚复杂系统干预规则挖掘的初步探索和成果,包括关于朴素干预规则和数值型干预规则挖掘算法,以及基于密度的数据流干预分析模型及相关结果。     

天然气水合物资源量的一种估算方法——以南海北部陆坡为例

根据天然气水合物物理化学相图平衡的基本原理,运用微积分学的基本理论,尝试一种新的天然气水合物资源量计算方法,并以南海北部陆坡为例对天然气水合物资源量进行了初步估算。天然气水合物稳定分布区可看成由许多微体积单元组成,对所有微体积单元进行累积积分计算出天然气水合物的分布体积;然后结合世界上已知天然气水合物分布的有关参数(如天然气水合物沉积层的孔隙度、天然气水合物的饱和度和水合系数)估算南海北部陆坡天然气水合物的潜在资源量。估算结果为,南海北部陆坡天然气水合物资源量约相当于标准条件下6.3×10¹³m³的天然气,这与美国Blake海底高原、日本Nankai海槽、美国墨西哥湾北部天然气水合物资源甲烷量的数量级(10¹³m³)一致,显示了南海北部陆坡天然气水合物资源的巨大前景。当然,南海北部陆坡天然气水合物的潜在资源量还有待于进一步调查核实。     

一种有效的智能天线波束成形技术

提出了一种新的智能天线算法,这种算法结合了多用户联合检测技术和RAKE接收技术,具有较小的运算量和良好的误码率性能,仿真的结果也证明了这是一种可行的方法,特别是在大的用户数目的情况下,智能天线的性能要远远好于一般的阵列天线的性能。