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Modified artificial neural network model with an explicit expression to describe flow behavior and processing maps of Ti2AlNb-based superalloy

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Journal of Iron and Steel Research International 2021年第11期28卷 1451-1462页

作者： Yan-qi Fu Qing Zhao Man-qian Lv Zhen-shan Cui School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China Institute of Forming Technology and Equipment Shanghai Jiao Tong UniversityShanghai 200030China

The elevated-temperature deformation behavior of Ti2AlNb superalloy was observed by isothermal compression experiments in a wide range of temperatures(950–1200°C)and strain rates(0.001–10 s^(-1)).The flow behavior is nonlinear,strongly coupled,and *** constitutive models,namely the double multivariate nonlinear regression model,artificial neural network model,and modified artificial neural network model with an explicit expression,were applied to describe the Ti2AlNb superalloy plastic deformation *** comparative predictability of those constitutive models was further evaluated by considering the correlation coefficient and average absolute relative *** comparative results show that the modified artificial network model can describe the flow stress of Ti2AlNb superalloy more accurately than the other developed constitutive *** explicit expression obtained from the modified artificial neural network model can be directly used for finite element *** modified artificial neural network model solves the problems that the double multivariate nonlinear regression model cannot describe the nonlinear,strongly coupled,and multivariable flow behavior of Ti2AlNb superalloy accurately,and the artificial neural network model cannot be embedded into the finite element software ***,the modified artificial neural network model is mainly dependent on the quantity of high-quality experimental data and characteristic variables,and the modified artificial neural network model has not physical ***,the processing maps were applied to obtain the optimum processing parameters.

关键词： Modified artificial neural network model Ti2AlNb superalloy Double multivariate nonlinear regression model explicit expression Processing map

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Algebraic solution of differential geometric guidance command and time delay control

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Science China(Technological Sciences) 2015年第3期58卷 565-573页

作者： LI KeBo CHEN Lei TANG GuoJin College of Aerospace Science and Engineering National University of Defense Technology

According to the three-dimensional geometry of the engagement,the explicit algebraic expression of differential geometric guidance command(DGGC)is *** with the existing solutions,the algebraic solution is much simpler and better for the further research of the characteristics of *** delay control(TDC)is a useful method to tackle the uncertainty problem of a control *** on TDC,taking the target maneuvering acceleration as a disturbance,the estimation algorithm of the target maneuvering acceleration is presented,which can be introduced in DGGC to improve its ***,the augmented DGGC(ADGGC)is *** numerical simulation of intercepting a high maneuvering target is conducted to demonstrate the effectiveness of ADGGC.

关键词： differential geometric guidance command explicit expression time delay control target acceleration estimation

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Stress concentration factor expression for tension strip with eccentric elliptical hole

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Applied Mathematics and Mechanics(English Edition) 2012年第1期33卷 117-128页

作者： Lin LUO Yu XIANG Qi-zhi WANG State Key Laboratory of Hydraulics and Mountain River Engineering Chengdu 610065P.R.China Department of Civil Engineering and Applied Mechanics Sichuan UniversityChengdu 610065P.R.China

Two explicit expressions of the stress concentration factor for a tension finite-width strip with a central elliptical hole and an eccentric elliptical hole, respectively, are formulated by using a semi-analytical and semi-empiricai method. Accuracy of the results obtained from these expressions is better, and application scope is wider, than the results of Durelli＇s photo-elastic experiment and Isida＇s formula. When eccentricity of the elliptical hole is within a certain range, the error is less than 8%. Based on the relation between the stress concentration factor and the stress intensity factor, a stress intensity factor expression for tension strips with a center or an eccentric crack is derived with the obtained stress concentration factor expressions. Compared with the existing formulae and the finite element analysis, this stress intensity factor expression also has sufficient accuracy.

关键词： stress concentration factor explicit expression eccentric elliptical hole central elliptical hole tension finite-width strip semi-analytical method

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Optimal layout model of feeder automation equipment oriented to the type of fault detection and local action

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Protection and Control of Modern Power Systems 2023年第1期8卷 15-29页

作者： Ruizhi Chen Xihong Li Yanbo Chen Bishan Power Supply Branch of Chongqing Electric Power Company Chong-qingBishanChina North China Electric Power University BeijingChina

In feeder automation transformation there are difficulties in equipment and location *** help with this,an optimal layout model of feeder automation equipment oriented to the type of fault detection and local action is *** analyzes the coordination relationship of the three most common types of automation equipment,i.e.,fault indicator,over-current trip switch and non-voltage trip switch in the fault handling process,and the explicit expres-sions of power outage time caused by a fault on different layouts of the above three types of equipment are *** constraints of power supply reliability and the goal of minimizing the sum of equipment-related capital invest-ment and power interruption cost,a mixed-integer quadratic programming model for optimal layout is established,in which the functional failure probability of equipment is linearized using the 3δprinciple in ***,the basic characteristics of the proposed model are illustrated by different scenarios on the IEEE RBTS-BUS6 *** can not only take into account fault location and fault isolation to enhance user power consumption perception,but also can guide precise investment to improve the operational quality and efficiency of a power company.

关键词： Feeder automation Equipment layout optimization Power outage time explicit expression Mixed integer quadratic programming model Functional failure probability of equipment

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The Nearest Complex Polynomial with a Prescribed Zero

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Journal of Mathematical Research with Applications 2015年第1期35卷 39-55页

作者： Wenyu HU Zhongxuan LUO College of Mathematics and Computer Science Gannan Normal University School of Mathematical Sciences Dalian University of Technology School of Software Dalian University of Technology

Nearest polynomial with given properties has many applications in control theory and applied mathematics. Given a complex univariate polynomial f(z) and a zero α, in this paper we explore the problem of computing a complex polynomial f(z) such that f(α) = 0 and the distance ∥f-f ∥ is minimal. Considering most of the existing works focus on either certain polynomial basis or certain vector norm, we propose a common computation framework based on both general polynomial basis and general vector norm, and summarize the computing process into a four-step algorithm. Further, to find the explicit expression of f(z), we focus on two specific norms which generalize the familiar lp-norm and mixed norm studied in the existing works, and then compute f(z) explicitly based on the proposed algorithm. We finally give a numerical example to show the effectiveness of our method.

关键词： nearest polynomial explicit expression zero dual norm

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