Consistent indexing of a (set of) single crystal SAED pattern(s) with the ProcessDiffraction program

A computer program called "ProcessDiffraction" helps indexing a set of single crystal selected area electron diffraction (SAED) patterns by determining which of the presumed structures can fit all the measured patterns simultaneously. Distances and angles are measured in the digitalized patterns with a graphical tool by clicking on the two shortest non-collinear vectors (spots), using user-supplied calibration data. Centers of the spots and center of the pattern are optionally refined by the program. Suggested individual indexing solutions (consistent with an assumed unit cell) are listed by the program for each pattern. Simulated patterns are also consulted to check if the shortest calculated distances coincide with measured ones. Common solutions for the set are selected by checking the angles between the suggested zone axes against the angles between the experimental goniometer settings. The indexing process is manually controlled by selecting the candidate structures (one-by-one) for indexing and by specifying the tolerances for d-values, plane angles and zone angles. Patterns of any crystal system can be indexed successfully. Although error bars are larger in electron diffraction than in X-ray diffraction (XRD), frequently, many unrelated indexings are possible for any one electron diffraction pattern (irrespective of the indexing method), a set of SAED patterns can generally be indexed unambiguously, i.e. the three-dimensional reciprocal space can be identified correctly. Two other tools also help planning tilting experiments: zones along a plane can be listed (with their angles extended from a pre-selected zone in that plane) and zones lying at a given angle (specified with a tolerance) from a zone can also be identified (as they are situated between two cones). Another tool searches the XRD database directly either for advice on possible structures for a composition or to help calibration.     

Photon contribution to ambient dose equivalent H(10) in the wide-spectrum neutron reference fields of the IRSN

The photon contribution to ambient dose equivalent in several wide-spectrum reference neutrons fields of the Institute for Radiological Protection and Nuclear Safety were measured using a Geiger-Müller counter. For the investigated fields, the ratio of photon to neutron ambient dose equivalent ranged between 0.03 and 0.20. The results show that the Geiger-Müller tube is a versatile instrument for dosimetry in mixed photon-neutron fields if sufficient information for the calculation of corrections is available.     

浦东新区内河防洪警戒水位核定

随着浦东新区社会和经济的迅速发展、水利建设和防汛设施不断完善,全区江河水情及工情都发生了变化,现行内河防洪警戒水位标准已不能满足需要,因此需重新检验和制订相适应的警戒水位。为对城市防洪中暴雨引起的河道水位雍高进行预警,结合浦东河道水系,将全区划分成3个区域;将现有水位遥测站与区域空间分布相结合,选取各区域代表水位站;对各代表水位站的特征水位值做经验频率计算,得到常遇洪水位;根据各代表站的常遇洪水位,结合所在区域的水面积、河道防洪能力及社会经济条件等,综合核定得到各区域的警戒水位。新的警戒水位可满足需求,在汛期中有效地减少警戒水位超限次数。     

和睦桥流域同位素示踪剂划分事件水的试验研究

流量过程线的划分结果对流域滞时分析、降雨径流关系确定和坡地汇流计算影响很大。以和睦桥小流域为例,基于该区域2015~2016年4场降雨资料,运用同位素方法对流域的流量过程线进行划分,探究降水总量和平均雨强对事件水贡献比例的影响。结果表明,事件前水占总流量的百分比例很大(67.9%~98.3%),肯定了事件前水的重要性;总降水量和降雨强度与事件前水占总流量的百分比例均呈负相关,这主要与流域所处地理位置的气候条件和下垫面前期土壤含水量有关;不同雨型主要通过降雨事件过程中的蒸发作用来影响事件前水的贡献比例,而相同雨型的降雨事件可能与前期土壤含水量有关。     

基于改进ANP方法的新沂市水生态文明城市评价

为评价江苏省新沂市水生态文明城市的建设情况,根据指标体系的构建原则,结合地方特色,在现有评价指标的基础上新增四个重要指标。同时,利用熵权法和基于博弈论的综合赋权法改进网络层次分析法(ANP),并结合专家打分的方式对新沂市2012、2015年的建设状况做出评价。结果表明,到2015年,新沂市水生态文明城市建设已取得突出成就,综合得分大幅提升1.37分,各二级指标达标率均超过85%,其中尤以水文化、水安全及水管理方面进步最为显著;针对进步较小的水环境和水生态建设提出了改进措施,对进一步打造水生态文明城市有参考价值。     

布谷鸟搜索算法在梯级水库优化调度中的应用

针对梯级水库优化调度在求解时易出现维数灾及计算时间过长等问题,将布谷鸟搜索算法用于梯级水库优化调度问题求解。实例计算表明,应用布谷鸟搜索算法求解梯级水库优化调度问题时,不但能对水库优化调度模型进行有效求解,还能节约计算用时,为求解高维梯级水库优化调度提供了新的思路。     

存在隐藏终端的IEEE 802.11e多跳无线网络模型分析*

首次将802.11e的接入机制放入多跳环境中进行仿真分析和定量研究。提出一种新的多跳环境下802.11e网络模型,结合M/G/1/K排队模型,定量分析在隐藏终端影响下802.11e网络的MAC层吞吐率、MAC时延和帧丢失率,研究802.11e在多跳环境下性能表现的内在原因。经过仿真实验结果与数值分析结果的对比,验证了分析模型的准确性;通过有（无）隐藏终端影响下MAC层性能的对比分析,指出了802.11e在多跳无线网络中支持QoS的局限性：受隐藏终端的影响,802.11e对不同接入等级的业务提供QoS区分的性能明显降级。因而有必要研究隐藏终端问题的解决方案,提高802.11e在多跳环境下的性能。     

基于几何测度的图像置乱度算法研究

分析研究了现有的几种图像置乱度衡量算法,从图像置乱前后相邻像素之间的距离偏移和方向偏移两个方面考虑,提出了基于几何测度的图像置乱度算法;最后通过对比分析,证明该算法具有更好的实用性、有效性与优越性。     

常温注水井对含水层热贯通的影响机理分析

为探究常温注水井对水源热泵热贯通现象的影响,利用FlowHeat1.0软件模拟了3组情景下含水层渗流场、温度场时空分布特征,并分析了常温注水井对含水层热贯通的影响机理和抽水井水温变化规律。结果表明,常温注水井通过减小回灌井、常温注水井之间的水力坡度和延长地下水渗透途径的方式达到缓解热贯通的效果;回灌井、常温注水井流量比相同时,常温注水井在抽灌井连线的位置对含水层热贯通的影响小;抽灌量不变时,常温注水井与回灌井的流量比越大,常温注水井缓解热贯通的效果越明显;在有利地下水回灌的水源热泵系统中,布设常温注水井能有效地降低含水层热贯通程度。     

引调水PPP项目风险分担的区间模糊Shapley值方法

为协调引调水PPP项目风险分担,针对引调水工程特性,系统分析影响风险分担因子,并运用层次分析法和群组决策特征根法(AHP-GEM)对其进行赋权;然后在构造风险损失模糊函数的基础上,运用区间模糊Shapley值法对引调水PPP项目进行初始风险分担;最后结合风险分担影响因子对初始风险分担值进行修正,提出引调水PPP项目风险分担算法。案例分析表明,修正后的风险分担方案有效克服了人的有限预估风险水平及风险损失的波动性,且权衡了各参与方实际风险承担能力,更与实际相符。