Development and Application of a Power Law Constitutive Model for Eddy Current Dampers

Eddy current dampers (ECDs) have emerged as highly desirable solutions for vibration control due to theirexceptional damping performance and durability. However, the existing constitutive models present challenges tothe widespread implementation of ECD technology, and there is limited availability of finite element analysis (FEA)software capable of accurately modeling the behavior of ECDs. This study addresses these issues by developing anewconstitutivemodel that is both easily understandable and user-friendly for FEAsoftware. By utilizing numericalresults obtained from electromagnetic FEA, a novel power law constitutive model is proposed to capture thenonlinear behavior of ECDs. The effectiveness of the power law constitutive model is validated throughmechanicalproperty tests and numerical seismic analysis. Furthermore, a detailed description of the application process ofthe power law constitutive model in ANSYS FEA software is provided. To facilitate the preliminary design ofECDs, an analytical derivation of energy dissipation and parameter optimization for ECDs under harmonicmotionis performed. The results demonstrate that the power law constitutive model serves as a viable alternative forconducting dynamic analysis using FEA and optimizing parameters for ECDs.

Exact Solutions of a Power Law Fluid Model in Posttreatment Analysis of Wire Coating with Linearly Varying Boundary Temperature

In this paper, analysis of post-treatment of wire coating is presented. Coating material satisfies power law fluid model. Exact solutions for the velocity field, volume flow rate and average velocity are obtained. Moreover, the heat transfer results are presented for different cases of linearly varying on the boundaries. The variations of velocity, volume flow rate, radius of coated wire, shear rate and the force on the total wire are presented graphically and discussed.

Francis Turbine and Governor Improved Models Considering Step Closing Law of Guide Vanes for Power System Stability Analysis

The Francis turbine governing system models in PSD-BPA can’t precisely reflect the actual characteristics. Endeavor was done in this paper to solve the problem. An improved model of actuating mechanism was developed, which could reflect the step closing characteristic of hydro guide vanes. The effect of the inflection point value of actuating mechanism on load rejection was analyzed based on simulation. The non-linear Francis turbine model with power versus gate position module was researched in this paper. Based on field test, comparisons of simulation results with measured data were presented. The analysis demonstrates that the improved models of Francis turbine and governor proposed in this paper are more realistic than the models of BPA, and can be applied in power system simulation analysis better.

一种支持SoC数字电路老化及寿命的评估方法

使用Spice可靠性仿真技术和高温稳态寿命(HTOL)实验相结合的方法,研究不同的MOSFET器件组成的环振电路在持续翻转状态下,不同应力时间和应力电压对其寿命退化的影响。依据仿真结果和Power-Law模型建立数字电路的寿命预测理论模型。通过HTOL实验验证模型的准确性。结果表明,随着时间的增加,器件的寿命退化率逐渐增加,且随着时间的推移,寿命的变化率越来越小。随着应力电压的增加,器件的寿命退化率更快趋向于稳定。器件退化符合R-D模型,仿真结果与试验结果高度,进一步证实了本模型对SoC数字电路寿命预测的准确性。通过这种组合仿真和实验的方法,可以更加准确地评估数字电路的寿命,为芯片制造过程中的可靠性设计提供参考。

库区浮泥层纵向流速垂线分布特性研究

水库浮泥是存在于水库底部的一层高含沙水体,流动性较强,直接影响水库淤积形态和水库排沙,研究其运动规律对水库减淤优化调度具有重要意义。根据三峡库区实测泥沙矿物组成和级配资料,配置沙样进行流变试验,以幂律流变模型描述浮泥的本构关系。构建了浮泥运动的速度分布理论模型,通过水槽试验对模型进行了验证,计算结果与试验结果吻合较好。结果表明,浮泥运动速度随浮泥厚度、上层水流流速、床面坡度增大而增大,随浮泥密度增大而减少。沿水深方向浮泥纵向流速分布始终呈抛物线型,表层的浮泥流速要远大于底层浮泥,浮泥纵向流速沿垂向方向不断减少,最底部的浮泥几乎处于静止状态。

基于有限时间干扰观测器的改进模型水下机器人自适应鲁棒容错控制

针对无人水下机器人(unmanned underwater vehicle,UUV)工作中存在的执行器故障,在系统不确定性与外界干扰下,提出一种基于有限时间扰动观测器(finite time disturbance observer,FTDO),并结合改进模型的自适应鲁棒容错控制方法。一方面,FTDO能在有限时间内对外界环境干扰进行估计;另一方面利用滑模控制加上径向基神经网络(radial basis function neyral network,RBF)的万能逼近特性,建立带有执行器故障的输入补偿;其中改进模型的引入解决了系统不确定性导致的输入饱和,提高了稳定性与鲁棒性;其次采用一种新型的双幂趋近律使滑模量在更短时间收敛到稳态误差界内;仿真与水池实验结果表明了所提方法相对于滑模控制有着更好的容错效果。

隧洞平行摄影测量立体影像尺度差估计及匹配优化

为提升平行摄影隧洞序列影像的同名点匹配率及精度,对成像规律及匹配方法展开研究。提出了一种窗口尺度自动改正的LK光流法,核心是利用物像空间关系构建尺度差模型,并采用可变窗口进行特征点光流跟踪。结果表明:隧洞序列影像像点尺度差呈对称性径向分布,差异值符合幂函数模型增长趋势;将该方法应用在多组尺度差立体像对的匹配实验中,均取得了优于0.3个像素精度的实验结果,较基本光流法至少提升34.3%,最大提升45.5%。研究成果可为顾及尺度差的匹配方法提供参考,也可为隧洞平行摄影立体影像匹配提供基础。

基于电网调度系统的网络安全态势感知方法研究

由于网络外界病毒入侵的隐蔽性极高、入侵类型较多,病毒难以被全面地被感知,导致电网调度自动化系统运行安全受到威胁。为提升电网调度自动化系统网络的安全性,提出基于随机矩阵理论(random matrix theory,RMT)的电网调度自动化系统网络安全态势感知技术。采集电网调度自动化系统网络安全信息数据,构建病毒入侵环境下的安全状态分布模型,并利用该模型完成电网调度系统网络安全态势特征信息的提取。采用RMT中的M-P模型及单环定律对网络安全态势特征值在随机矩阵内的分布情况进行谱分析,根据特征值分布状态获取网络安全态势在稳定情况及异常情况下的变换规律,实现电网调度系统网络安全态势感知。实验结果表明,通过对该方法开展安全态势感知测试,验证了该方法应用在电网调度系统中组件安全态势感知及网络安全态势感知的精准度均较高,体现了该方法的有效性。

下垫面非均匀流域的幂指数TOPMODEL的模拟研究

利用取消流域土壤表层饱和导水率0K、土壤饱和导水率有效衰减系数m和地下水补给速率R为空间均匀假设的幂指数TOPMODEL,对流域水量平衡各分量进行敏感性研究试验,揭示空间非均匀性对幂指数TOPMODEL模拟结果的影响。从特定研究流域所得结果中可得的主要结论有:1)0K、m和R的空间变化对流域的逐日地表径流和基流以及逐日总径流有影响,针对设定的0K、m和R的空间变化,其中m的空间变化较明显地增加了逐日地表径流和洪峰流量。2)就设定的0K、m和R的空间变化而论,对流域多年平均年总径流以及蒸发模拟结果影响不大,但改变了径流在地表径流和基流之间的分配;其中R的空间变化影响最显著,m和0K的空间变化影响则较小。

非牛顿流固耦合问题的半隐式分区ALE有限元-间断有限元耦合算法研究

针对非牛顿流固耦合问题,提出了任意拉格朗日-欧拉(arbitrary Lagrangian-Eulerian,ALE)框架下的半隐式分区有限元-间断有限元耦合算法。其数学模型主要包括非牛顿流体和固体结构的控制方程,以及流体-固体交界面上的边界条件。固体结构由弹性材料组成,非牛顿流体由幂律型本构模型描述。用分裂格式对非牛顿流体控制方程进行解耦,得到若干子方程;通过有限元、间断有限元方法求解对应恰当类型的子方程。用中心差分及标准有限元方法分别对固体结构弹性动力学方程进行时间和空间离散;用修正的Laplace移动网格方法处理固体结构的形变及流体区域网格的变化过程。最后用数值算法研究了带有圆弧顶端梯形结构体的非牛顿流固耦合问题,并详细分析了结构体高度、入口速度及流体特性等因素对流固耦合问题的影响及机理。

利用多源数据融合在某铜金属矿山开展三维实体建模的研究

采用3Dmine三维建模软件结合地质数据、工程测量数据、图件矢量化数据等多源数据融合,构建某铜金属矿山多源信息数据库,并建立了该矿的三维地表DTM模型、矿体三维模型、构造模型、岩性模型、井巷工程三维模型以及矿体块体模型等,利用距离幂次反比法对矿体矿石量、金属量、品位等进行了估值,并与矿山储量核实报告获得的结果进行了对比分析。实践表明,所建模型估算的品位、矿石量、金属量结果可靠,可以有效地展示矿山深部矿体、围岩、断层、井巷工程等三维地下空间的可视化,并为矿山深部矿床的探矿设计、开采设计提供有效依据。

Adventures Beyond Amdahl's Law:How Power-Performance Measurement and Modeling at Scale Drive Server and Supercomputer Design

Amdahl’s Law painted a bleak picture for large-scale computing.The implication was that parallelism was limited and therefore so was potential speedup.While Amdahl’s contribution was seminal and important,it drove others vested in parallel processing to define more clearly why large-scale systems are critical to our future and how they fundamentally provide opportunities for speedup beyond Amdahl’s predictions.In the early 2000s,much like Amdahl,we predicted dire consequences for large-scale systems due to power limits.While our early work was often dismissed,the implications were clear to some:power would ultimately limit performance.In this retrospective,we discuss how power-performance measurement and modeling at scale led to contributions that have driven server and supercomputer design for more than a decade.While the influence of these techniques is now indisputable,we discuss their connections,limits and additional research directions necessary to continue the performance gains our industry is accustomed to.

服务国家需要 推进模式创新提高我国法治国际传播力

涉外法治人才培养是涉外法治建设的重要基础和保障,是政法院校适应国家需要、服务国家战略的时代责任。上海政法学院坚持以习近平法治思想为指引,主动服务国家战略,紧密对接国家急需,依托中国上合基地优势,探索涉外法治人才培养模式创新,努力培养德法兼修的高素质涉外法治人才,推进法治领域国际交流合作,为提高我国法治国际传播力贡献力量。

刑事诉讼中个人信息保护的模式选择及其制度完善

个人信息保护权承载数字时代公民的人格尊严与自由平等价值,具有基本权特点和宪法可解释性,作为基本权利导入刑事诉讼程序具有必要性和可能性。我国刑事诉讼领域个人信息保护应以个人信息权与隐私权共同作为权利基础,构建个人信息权与隐私权结合的复合型权利保护模式。在权利保护层面,以隐私标准作为划分依据,将个人信息分为一般信息与隐私信息,对应个人信息权的一般保护规则和隐私权的更高程度的保护规则,通过信息知情权、信息决定权、信息访问权、信息更正权、信息删除权与解释说明权六项子权利提供全过程、合比例的保护。在权力规制层面,以法律保留原则与比例原则作为主要规范工具,明确公安司法机关干预个人信息的授权条款和保护个人信息的义务条款,完善干预行为的权责配置,对干预行为进行合比例的程序规制。在制度衔接层面,将个人信息保护规则适度引入刑事诉讼制度,有效衔接个人信息保护法与刑事诉讼法规定,强化规范公安司法机关处理个人信息行为。

Rheology of rock salt for salt tectonics modeling

Numerical modeling of salt tectonics is a rapidly evolving field; however, the constitutive equations to model long-term rock salt rheology in nature still remain controversial. Firstly, we built a database about the strain rate versus the differential stress through collecting the data from salt creep experiments at a range of temperatures（20–200 ℃） in laboratories. The aim is to collect data about salt deformation in nature, and the flow properties can be extracted from the data in laboratory experiments.Moreover, as an important preparation for salt tectonics modeling, a numerical model based on creep experiments of rock salt was developed in order to verify the specific model using the Abaqus package. Finally, under the condition of low differential stresses, the deformation mechanism would be extrapolated and discussed according to microstructure research. Since the studies of salt deformation in nature are the reliable extrapolation of laboratory data, we simplified the rock salt rheology to dislocation creep corresponding to power law creep（n = 5） with the appropriate material parameters in the salt tectonic modeling.

Modeling online social networks based on preferential linking

We study the phenomena of preferential linking in a large-scale evolving online social network and find that the linear preference holds for preferential creation, preferential acceptance, and preferential attachment. Based on the linear preference, we propose an analyzable model, which illustrates the mechanism of network growth and reproduces the process of network evolution. Our simulations demonstrate that the degree distribution of the network produced by the model is in good agreement with that of the real network. This work provides a possible bridge between the micro=mechanisms of network growth and the macrostructures of online social networks.

A local-world evolving hypernetwork model

Complex hypernetworks are ubiquitous in the real system. It is very important to investigate the evolution mecha- nisms. In this paper, we present a local-world evolving hypernetwork model by taking into account the hyperedge growth and local-world hyperedge preferential attachment mechanisms. At each time step, a newly added hyperedge encircles a new coming node and a number of nodes from a randomly selected local world. The number of the selected nodes from the local world obeys the uniform distribution and its mean value is m. The analytical and simulation results show that the hyperdegree approximately obeys the power-law form and the exponent of hyperdegree distribution is 7 = 2 ＋ 1/m. Furthermore, we numerically investigate the node degree, hyperedge degree, clustering coefficient, as well as the average distance, and find that the hypemetwork model shares the scale-flee and small-world properties, which shed some light for deeply understanding the evolution mechanism of the real systems.

A DISCUSSION ON FRESNEL APPROXIMATION IN PHASE SCREEN MODEL

The Fresnel approximation in phase screen model is discussed and the coherencefunction is derived for k】】k.The application condition for Rino’s results is obtained,and it is|▽R△Ne|/R△ne【【1.

Novel extended C-m models of flow stress for accurate mechanical and metallurgical calculations and comparison with traditional flow models

Here,we developed novel extended piecewise bilinear power law(C-m)models to describe flow stresses under broad ranges of strain,strain rate,and temperature for mechanical and metallurgical calculations during metal forming at elevated temperatures.The traditional C-m model is improved upon by formulating the material parameters C and m,defined at sample strains and temperatures as functions of the strain rate.The coefficients are described as a linear combination of the basis functions defined in piecewise patches of the sample strain and temperature domain.A comparison with traditional closed-form function flow models revealed that our approach using the extended piecewise bilinear C-m model is superior in terms of accuracy,ease of use,and adaptability;additionally,the extended C-m model was applicable to numerical analysis of mechanical,metallurgical,and microstructural problems.Moreover,metallurgy-related values can be calculated directly from the flow stress information.Although the proposed model was developed for materials at elevated temperatures,it can be applied over a broad temperature range.

Nonlinear Mixed-Effects Models for Repairable Systems Reliability

Mixed-effects models,also called random-effects models,are a regression type of analysis which enables the analyst to not only describe the trend over time within each subject,but also to describe the variation among different subjects.Nonlinear mixed-effects models provide a powerful and flexible tool for handling the unbalanced count data.In this paper,nonlinear mixed-effects models are used to analyze the failure data from a repairable system with multiple copies.By using this type of models,statistical inferences about the population and all copies can be made when accounting for copy-to-copy variance.Results of fitting nonlinear mixed-effects models to nine failure-data sets show that the nonlinear mixed-effects models provide a useful tool for analyzing the failure data from multi-copy repairable systems.