Global Comprehensive Sensitivity Analysis of Arch Dam Construction Parameters Based on Orthogonal Experiment

The construction of arch dams exhibits high uncertainty. Sensitivity analysis of construction parameters is important for the design and optimization of dam construction duration. However, current research cannot fully consider the combined influences of multiple parameters on the total construction. To effectively analyze the duration of arch dam construction, this study proposes a global comprehensive sensitivity analysis method in view of the whole process of arch dam construction based on an orthogonal experiment. This method could comprehensively consider the influence of the construction parameters that may lead to the uncertainty of construction duration. In addition, this method is able to identify the key parameters that may have a significant effect on duration uncertainty and sums up the general rules of combined parameters’ interaction effect, which provides a scientific basis for reasonable optimization of the duration of dam construction. © 2017, Tianjin University and Springer-Verlag GmbH Germany.

Analysis of the Intrinsic Uncertainties in the Laser-Driven Iron Hugoniot Experiment Based on the Measurement of Velocities

One of the most challenging tasks in the laser-driven Hugoniot experiment is how to increase the reproducibility and precision of the experimental data to meet the stringent requirement in validating equation of state models. In such cases, the contribution of intrinsic uncertainty becomes important and cannot be ignored. A detailed analysis of the intrinsic uncertainty of the aluminum-iron impedance-match experiment based on the measurement of velocities is presented. The influence of mirror-reflection approximation on the shocked pressure of Fe and intrinsic uncertainties from the equation of state uncertainty of standard material are quantified, Furthermore, the comparison of intrinsic uncertainties of four different experimental approaches is presented. It is shown that, compared with other approaches including the most widely used approach which relies on the measurements of the shock velocities of AI and Fe, the approach which relies on the measurement of the particle velocity of Al and the shock velocity of Fe has the smallest intrinsic uncertainty, which would promote such work to significantly improve the diagnostics precision in such an approach.

Inversion method for multi-point source pollution identification:Sensitivity analysis and application to European Tracer Experiment data

Fast and accurate identification of unknown pollution sources plays a crucial role in the emergency response and source control of air pollution.In this work,the applicability of a previously proposed two-step inversion method is investigated with sensitivity experiments and real data from the first release of the European Tracer Experiment(ETEX-1).The two-step inversion method is based on the principle of least squares and carries out additional model correction through the residual iterative process.To evaluate its performance,its retrieval results are compared with those of two other existing algorithms.It is shown that for those cases with richer measurements,all three methods are less sensitive to errors,while for cases where measurements are sparse,their retrieval accuracy will rapidly decrease as errors increase.From the results of sensitivity experiments,the new method provides higher estimation accuracy and a more stable performance than the other two methods.The new method presents the smallest maximum location error of 18.20 km when the amplitude of the measurement error increases to 100%,and 22.67 km when errors in the wind fields increase to 200%.Moreover,when applied to ETEX-1 data,the new method also exhibits good performance,with a location error of 4.71 km,which is the best estimation with respect to source location.

Identifying uncertainty sources in measurements-A methodology

The overall purpose of performing measurements in science is to increase knowledge and document about some physical quantity. The measurand has a true value but, except for straightforward counting situations, the true value can never be fully determined. When a quantity is measured, the outcome depends on the measuring system, the measurement procedure, the skill of the operator, the environment and other effects. In practice the uncertainty on the result may arise from many possible sources, including examples such as incomplete definition, sampling, matrix effects and interferences, environmental couditions, uncertainties of weights and volumetric equipment, reference wtlues, approximations and assump- tions incorporated in the measurement method and procedure, and random wlriation. The objective of the paper is how to identify the sources of uncertainty in measurement and their importance on the result.

Inverse uncertainty characteristics of pollution source identification for river chemical spill incidents by stochastic analysis

Identifying source information after river chemical spill occurrences is critical for emergency responses.However,the inverse uncertainty characteristics of this kind of pollution source inversion problem have not yet been clearly elucidated.To fill this gap,stochastic analysis approaches,including a regional sensitivity analysis method,identifiability plot and perturbation methods,were employed to conduct an empirical investigation on generic inverse uncertainty characteristics under a well-accepted uncertainty analysis framework.Case studies based on field tracer experiments and synthetic numerical tracer experiments revealed several new rules.For example,the release load can be most easily inverted,and the source location is responsible for the largest uncertainty among the source parameters.The diffusion and convection processes are more sensitive than the dilution and pollutant attenuation processes to the optimization of objective functions in terms of structural uncertainty.The differences among the different objective functions are smaller for instantaneous release than for continuous release cases.Small monitoring errors affect the inversion results only slightly,which can be ignored in practice.Interestingly,the estimated values of the release location and time negatively deviate from the real values,and the extent is positively correlated with the relative size of the mixing zone to the objective river reach.These new findings improve decision making in emergency responses to sudden water pollution and guide the monitoring network design.

铀溶液多体系统核临界安全实验不确定度分析与基准化

为研究铀溶液多体系统的核临界安全特性,中国原子能科学研究院利用铀溶液核临界安全实验装置开展了两个系列的双平板式多体系统核临界安全实验,并完成了所有实验数据的不确定度分析和基准化。铀溶液多体系统由正对的两个相同尺寸的平板容器组成,平板容器之间的距离和隔离体能够改变,开展了距离效应和屏蔽效应共24个临界实验。根据国际核临界安全基准实验手册(ICSBEP)提出的不确定度分析方法进行了实验的不确定度分析,最大的总不确定度为200 pcm。建立了全部实验的详细基准模型,对两套蒙特卡罗软件与核截面数据库的组合计算特定系统k_(eff)的适用性进行了评价。两套组合的计算值与基准值的最大计算偏差分别为309.0 pcm和252.0 pcm,确认这两套组合均可用于相关系统的临界安全设计或安全分析。

阿勒泰市移动源排放清单及时空分布特征

通过“自上而下”调查方式获取移动源活动水平,采用排放因子法建立了阿勒泰市移动源排放清单,并进行移动源排放的时空特征分析和清单不确定性分析。结果表明,2021年阿勒泰市移动源9种大气污染物排放总量,CO为669.12 t,NO_(x)为617.92 t,SO_(2)为29.85 t,NH_(3)为32.61 t,VOCs为136.35 t,PM_(2.5)为35.74 t,PM_(10)为38.06 t,BC为20.33 t,OC为6.41 t。其中,CO、SO_(2)、NH_(3)、VOCs主要来源于载客汽车,贡献率均超过40%;NO_(x)主要来源于农业机械和载货汽车,贡献率均超过30%;PM_(2.5)、PM_(10)、BC、OC主要来源于农业机械,贡献率均超过75%。时空分布特征表现为6—8月排放量最高,人口密集的市区排放量高于其他区域。移动源9种污染物排放清单不确定性均在−39.23%~56.27%以内,本清单计算结果相对可靠。

本科量子物理实验课程探索

近20年,国际量子科技取得重大进展,在未来科技发展中占据重要地位.因此,在物理专业本科实验教学中设置量子物理实验,让学生深入理解微观量子物理基本原理,掌握一定的量子前沿技术非常必要.华东师范大学物理学专业自主开发量子物理本科实验教学仪器和虚拟仿真实验,在物理学专业拔尖班开设量子物理实验,取得了优异的成果.本文详细介绍了华东师范大学量子物理实验课程设置以及实施过程,分析开展相关本科量子物理实验的可能性及其普及性,为全国高校开设量子物理实验课程提供参考.

严重事故工况下反应堆热工水力参数对源项释放行为影响研究

为了进一步研究反应堆严重事故进程中热工参数对源项释放的影响,识别对其影响较大的物理过程,从而进一步改进和发展数值模型以提高计算精度降低不确定性,以第三代压水堆为对象,利用一体化严重事故分析程序ISAA对大破口失水事故导致的严重事故开展了数值分析研究,并基于Wilks公式利用自主开发的不确定性程序代码SAUP对17个热工参数进行了拉丁超立方抽样(LHS)执行批量计算,对目标输出(FoM)即氢气与裂变产物的释放进行了不确定性与敏感性分析。结果表明:在热工参数的不确定性范围内,氧化产氢以及裂变产物的释放呈现正态分布且存在较大的不确定带,包壳氧化层的失效温度、堆芯碎片尺寸以及碎片孔隙率对高挥发性裂变产物的释放有较为显著的相关性。该研究有助于理解反应堆严重事故中热工参数与源项之间的复杂联系,同时对核电厂安全系统的设计以及严重事故的预防与缓解具有参考意义。

基于多源数据融合的土体空间参数不确定性缩减

土体参数存在空间变异性,导致结构响应具有不确定性。忽视这种不确定性或采用偏差参数可能导致工程安全问题,甚至引发工程灾害。现场测量数据可用于改进对基坑开挖等岩土工程中结构响应的估计,通过SPT等直接测量方法得到的勘察数据与土体刚度参数直接相关,在这些数据的基础上,基于Kriging法约束随机场的条件模拟可用于改进对参数空间分布的估计。此外,当监测数据与位移等土体结构性能或响应相关时,利用集合卡尔曼滤波器(EnKF)反分析也可降低土体参数的不确定性。本文采用多源数据融合的形式将直接和间接两种方法结合在一起进行土体开挖分析,结果表明:两种方法结合使用可以显著降低土体参数的不确定性,从而降低结构响应中的不确定性。

Evaluating 3D position and velocity of subject in parabolic flight experiment by use of the binocular stereo vision measurement

A practical method for evaluating the three-dimensional（3D） position and velocity of a moving object used in the parabolic flight experiment is developed by using the binocular stereo vision measurement theory. The camera calibration mathematic model without considering the lens distortion is introduced.The direct linear transformation（DLT） algorithm is improved to accomplish the camera calibration.The camera calibration result and optimization algorithm are used to calculate the object＇s world coordinate from image coordinate.The 3D position and the velocity of the moving object are obtained.The standard uncertainty in estimating the velocity is 0.0024 m/s,which corresponds to 1%level of the velocity of the object in the experiment.The results show that this method is very useful for the parabolic flight experiments.

考虑源-荷不确定性的省间电力现货市场潮流风险概率评估

新型电力系统建设背景下可再生能源占比逐渐提高,源-荷双侧不确定性使省间电力现货市场运行风险增加。针对该问题,提出一种考虑源-荷双侧不确定性的省间电力现货市场联络线潮流风险概率评估方法。首先,分析源-荷双侧不确定性对省间电力现货市场出清的影响,建立源-荷联合不确定性模型为市场出清提供数据基础。然后,设计省间电力现货市场出清双层优化模型,以计算省间联络线的潮流出清结果。最后,为表征源-荷双侧不确定性给电力市场出清安全带来的风险,提出联络线容量占用率、潮流概率稳定度和潮流稳定风险度等多个指标对联络线潮流进行了不确定性风险评估。利用某省电力公司数据进行了仿真测试,并将结果与不同不确定性建模方法、不同置信区间下的评估结果对比,验证了所提方法的有效性。

基于互联网技术的源荷互动配电网规划模式

高比例可再生能源接入电网带来大量不确定性因素,传统确定性规划方式将导致系统设备利用率低、弃风弃光严重等问题。基于互联网建立全面、实时和共享的规划数据体系,实现电源侧和负荷侧双方信息透明交互,从而避免规划的盲目性。计及源荷特性进行概率建模,运用多场景分析模拟源荷间不确定性,基于改进M-K聚类算法确定源荷典型场景。构建上层以规划综合成本最低为目标,下层从经济、技术和安全三个角度进行优化的双层规划模型,应用免疫遗传算法进行求解。最后通过对配电网区域和整体算例进行比较验证,结果表明基于互联网技术的规划模式能有效降低电网容载比和规划综合成本,同时减少弃风弃光现象。

Erratum:Measurement of(n,α)and(n,2n)reaction cross sections at a neutron energy of 14.92±0.02 MeV for potassium and copper with uncertainty propagation,[A.Gandhi,Aman Sharma,Rebecca Pachuau et al.,Chin.Phys.C 46,014002(2022)]

Experimentally measured neutron activation cross sections are presented for the^(65)Cu(n,α)^(62m)Cu,^(41)K(n,α)^(38)Cl,and^(65)Cu(n,2n)^(64)Cu reactions with detailed uncertainty propagation.The neutron cross sections were measured at an incident energy of 14.92±0.02 MeV,and the neutrons were based on the t(d,n)αfusion reaction.The^(27)Al(n,α)^(24)Na reaction was used as a reference reaction for the normalization of the neutron flux.The pre-calibrated lead-shielded HPGe detector was used to detect the residues'γ-ray spectra.The data from the measured cross sections are compared to the previously measured cross sections from the EXFOR database,theoretically calculated cross sections using the TALYS and EMPIRE codes,and evaluated nuclear data.

多参数监护仪检定装置测量不确定度分析

该文针对多参数监护仪的各个参数在日常检定时,能得到更加准确可靠的测量数据,从A类不确定度测量重复性及被检设备分辨力,与B类不确定度测量标准器准确度等不确定度分量去分析,结果得出各个相关参数的测量不确定度,电压2.6%、扫描速度1.3%、幅频特性2.9%、心率、脉率、呼吸率均为1.3次/min、压力1.2mmHg、呼末二氧化碳浓度1.1mmHg,可供从事多参数监护仪检定人员参考。

临界事故报警系统的相似性

为了确定用于场所监测的临界事故报警系统合适的报警阈值,需选用相似的基准实验进行验证。根据设备室临界事故报警系统的特征,构建了简易模型和具有代表性的包含多个设备的虚拟设备室模型。针对固定源问题,在蒙卡程序(RMC)中实现了基于微分算符抽样法计算敏感性系数的功能。随后,运用敏感性和不确定度分析方法对系统间的相似性进行了研究,并深入分析了影响相似性的因素。计算分析结果显示,对于简易模型,源项能谱和混凝土材料对系统间的相似性有较大影响,探测器与内侧墙面之间的混凝土厚度对相似性有一定影响,而源项的几何位置对相似性的影响较小,乏燃料成分对相似性的影响可以忽略不计。根据本文提出的相似性分析流程进行计算得出,简易模型与虚拟设备室模型的相似性较高,基于简易模型的研究结论适用于虚拟设备室模型,可为工程上的临界报警系统相似性研究提供参考。

基于数字孪生的空间电源产品测试系统建设与应用

数字孪生技术以数字化描述物理实体,通过物理世界与信息化虚拟世界的交互与融合,为打通测试试验现场与管理层间的数据壁垒提供有力的支撑。上海空间电源研究所结合五维数字孪生理论,以空间电源产品为对象进行开发与实践,实现测试试验委托与排产、产品测试试验数据采集、场景建模、测试试验过程实时监控以及数据分析等功能,提高测试试验管理效率,并探索虚拟试验的可行性,为降低型号试验成本和试验精细化管理升级奠定坚实基础。

基于氮素迁移规律的农业非点源污染与防治研究——以梅林流域2019年观测实验为例

为探究农业非点源污染的迁移规律,针对性地提出农业非点源污染防治措施,文章选择太湖西侧的梅林实验流域为研究区,以氮素为代表性研究对象,开展多场次降雨径流观测实验,从单峰型、多峰型径流过程及径流峰值前、中、后各时段进行分析,借助相关系数分析非点源氮素污染迁移与降雨径流深的内在联系。结果表明:无机氮流失占研究区氮素流失的主体,其中NO_(3)^(-)-N流失量显著大于NH_(4)^(+)-N;TN、NH_(4)^(+)-N、NO_(3)^(-)-N的流失量与地表径流深均呈现明显的正相关关系,相关系数R均为0.95左右。研究区农业非点源氮素污染防治可从径流产生量削减、汇流过程吸收固氮、生物有机肥替代氮肥等方面采取措施。

直接测汞仪法测定煤中汞含量的不确定度分析

煤中汞含量是评价商品煤质量的重要指标之一,为合理地表征煤中汞含量的测定值,需分析评定整个测量过程中的系统影响和随机影响给被测量造成的分散性,即测量不确定度。研究分析直接测汞仪法测定煤中汞含量的不确定度主要来源,通过对各个分量相对不确定度、合成不确定度和扩展不确定度的统计计算,得出煤中汞含量测定的不确定度。结果表明,建立测量工作曲线使用的移液管、容量瓶及移液器等量具引入的不确定度最大,其相对不确定度为2.76×10^(-2),而试样称量、汞标准溶液、曲线拟合、测量重复性等引入的不确定度较小。通过选用合适的非线性曲线拟合不确定度评定方法,综合得出测试样品应用直接测汞仪法测定煤中汞含量及不确定度为(0.104±0.006)μg/g,k=2。

源储网联合规划中风电出力不确定性的影响

为研究风电出力不确定性对源储网联合规划的影响,以东北地区某省某新能源基地风电输出为例,分析了风电特性对源储网规划的影响,并使用DCGAN和K–means进行了风电场景生成和缩减优化,描述了风力发电的不确定性。研究结果表明,文章所提生成场景预测精度、可靠性优良,可准确评价源储网联合规划中风力发电的不确定性影响。