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Journal of Magnesium and Alloys 2022年第5期10卷 1256-1267页

作者： y.J.Wan y.Zeng y.c.dou D.c.Hu X.y.Qian Q.Zeng K.X.Sun G.F.Quan Key Laboratory of Advanced Technologies of Materials Ministry of EducationSchool of Material Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China college of Materials Science and Engineering Sichuan University of Science and EngineeringZigong 643000China Department of Materials The University of ManchesterOxford RoadManchester M139PLUnited Kingdom

Aging prior to twinning deformation was proposed to alter the precipitate orientation of the plate-shapedβ-MgAlfrom(0002)basal planes(named basal plates)to■prismatic planes(named prismatic plates)in AZ31 Mg *** experimental results showed that the compressive yield strength(cyS)of the sample containing prismatic plates increased 40 MPa and the compression ratio raised by 22%compared to that containing basal *** underlying strengthening mechanism was analyzed via a yield strengthen(yS)model with a function of grain size,precipitate characters(size,oritention,fraction)and Schmid factor(SF).It revealed that the improvement of cyS was mainly attributed to the altered precipitate orientation and refined grain size produced by twinning ***,the prismatic plates always have a stronger hardening effect on basal slip than basal plates under the same varites of precipitate diameter and ***,the decreased cRSS ratio of prismatic slip to basal slip revealed that the activity of non-basal slip in Mg alloy might be *** activated slip systems provided more mobile dislocations,contributing to the large compression ratio of the Mg rolled sheet with prismatic plates.

关键词： Precipitate orientation Precipitation strengthening Grain boundary strengthening yield strength model

Prior-based patch-level representation learning for electric vehicle battery state-of-charge estimation across a wide temperature scope

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Science china Technological Sciences 2024年第12期67卷 3682-3694页

作者： yE SongTao AN dou Faculty of Electronic and Information Engineering Xi'an Jiaotong University

Electric vehicles(EVs) powered by lithium-ion batteries have emerged as a global development trend. To ensure the safe and stable driving of EVs, it is imperative to address battery safety and thermal management issues, which rely heavily on the precise state-of-charge(SOc) estimation of the battery. However, estimating SOc under uncontrolled environmental temperatures remains an unresolved challenge. This study proposes a patch-level representation learning model based on domain knowledge to estimate the SOc over a wide temperature range. First, patches were adopted as inputs instead of traditional points, thereby mitigating error accumulation and capturing dynamic changes in the battery from these more informative ***, the open-circuit voltage(OcV)-SOc-temperature relationship was incorporated to obtain the temperature-related SOc priors. Subsequently, the prior was updated recursively along the time dimension to obtain a more precise SOc estimate. The accuracy of the proposed model was confirmed experimentally for three driving cycles at six ambient temperatures, significantly reducing the root mean square error by 48.19% compared to popular existing models. Notably, the performance of the proposed method had an excellent improvement of 51.52% and 57.20% at-10°c and-20°c, respectively. Moreover, the parameter size of the proposed method was 39.748 KB, which significantly promoted the deployment and application of data-driven models in the real world.

关键词： lithium-ion battery data-driven prior knowledge state-of-charge wide temperature scope

Experimental methods for determination of mechanical behaviors of materials at high temperatures via the split Hopkinson bars

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Acta Mechanica Sinica 2020年第6期36卷 1275-1293,I0003页

作者： Q.B.dou K.R.Wu T.Suo c.Zhang X.Guo y.Z.Guo W.G.Guo y.L.Li School of Aeronautics Northwestern Polytechnical UniversityXi’an710072China Joint International Research Laboratory of Impact Dynamics and its Engineering Application Xi’an710072China Shaanxi Key Laboratory of Impact Dynamics and its Engineering Application Xi’an710072China State Key Laboratory for Strength and Vibration of Mechanical Structures School of AerospaceXi’an Jiaotong UniversityXi’an710049China

Full understanding of the thermomechanical behaviors of materials at high strain rates and high temperatures are of great importance from not only scientific meaning but also practical value in engineering structure design and safety *** efforts have been made for abilities of operation the split Hopkinson bars,the most popular technique for experimental determination of mechanical behaviors of materials over the strain rates from 10^2 to 10^4 s^−1 over the past 70 years,at high temperatures since 1960s.A review of experiment work is presented in this paper to give an overview of the development of experimental techniques at high temperatures based on Hopkinson bar *** principles of the split Hopkinson bar requires the loading bars avoiding temperature gradient or keeping relatively low temperature when performing high temperature *** such as performing temperature gradient corrections,rapid heating or using special designed automatically assembled systems were proposed by researchers to enable the operation of the split Hopkinson bars at temperature as high as ***,to the application of high speed photographic technique for capturing the dynamic deformation process of the specimen in high temperature Hopkinson bar testing,some key issues of eliminating the strong thermal radiation induced lights oversaturation and de-blurring of images due to insufficient exposure at high temperature and high strain rate condition,as well as fabrication of high contrast speckle pattern for high temperature digital image correlation measurement were also *** technique can now enable the split Hopkinson bar testing to be performed at high temperature up to 1873 K under the loading conditions of compression or tension with the in situ observation and full field measurement of deformation as *** paper concludes with summaries of the most important achievements and highlighting of the prospects,trends and remaining challenge

关键词： Mechanical behaviors Split Hopkinson bar High strain rate High temperature

Formation control with obstacle avoidance of second-order multi-agent systems under directed communication topology

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Science china(Information Sciences) 2019年第9期62卷 144-157页

作者： Guoxing WEN c.L.Philip cHEN Hui dou Hongli yANG chunfang LIU college of Science Binzhou University Department of computer and Information Science Faculty of Science and Technology University of Macau college of Navigation Dalian Maritime University State Key Laboratory of Management and control for complex Systems Institute of AutomationChinese Academy of Sciences Mathematics and Systems Science college Shandong University of Science and Technology

This paper addresses the obstacle avoidance problem of formation control for the multi-agent systems modeled by double integrator dynamics under a directed interconnection topology. The control task is finished by a leader-follower formation scheme combined with an artificial potential field(APF) *** leader-follower scheme is carried out by taking the desired trajectory with the desired velocity as virtual leader, while the APF method is carried out by dealing with the obstacles as the high potential points. When the obstacle avoidance tasks are finished, the artificial potential forces degrade the formation performance, so their undesired effects are treated as disturbances, which is analyzed by the robust H∞performance. Based on Lyapunov stability theory, it is proved that the proposed formation approach can realize the control objective. The result is also extended to the switching multi-agent formation. The effectiveness of the proposed formation scheme is further confirmed by simulation studies.

关键词： formation control obstacle avoidance artificial potential field method H_∞ performance second-order multi-agent system directed topology

Simulation and Instability Investigation of the Flow around a cylinder between Two Parallel Walls

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Journal of Thermal Science 2015年第2期24卷 140-148页

作者： dou Hua-Shu BEN An-Qing Faculty of Mechanical Engineering and Automation Zhejiang Sci-Tech University

The two-dimensional flows around a cylinder between two parallel walls at Re=40 and Re=100 are simulated with computational fluid dynamics(cFD). The governing equations are Navier-Stokes equations. They are discretized with finite volume method(FVM) and the solution is iterated with PISO Algorithm. Then, the calculating results are compared with the numerical results in literature, and good agreements are obtained. After that, the mechanism of the formation of Karman vortex street is investigated and the instability of the entire flow field is analyzed with the energy gradient theory. It is found that the two eddies attached at the rear of the cylinder have no effect on the flow instability for steady flow, i.e., they don't contribute to the formation of Karman vortex street. The formation of Karman vortex street originates from the combinations of the interaction of two shear layers at two lateral sides of the cylinder and the absolute instability in the cylinder wake. For the flow with Karman vortex street, the initial instability occurs at the region in a vortex downstream of the wake and the center of a vortex firstly loses its stability in a vortex. For pressure driven flow, it is confirmed that the inflection point on the time-averaged velocity profile leads to the instability. It is concluded that the energy gradient theory is potentially applicable to study the flow stability and to reveal the mechanism of turbulent transition.

关键词： numerical simulation cylinder energy gradient theory stability inflection point

Geology and c-O isotope geochemistry of carbonate-hosted Pb-Zn deposits, NW Guizhou Province, SW china

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chinese Journal Of Geochemistry 2013年第1期32卷 7-18页

作者： dou Song ZHOU Jiaxi yunnan Nonferrous Metals Geological Bureau School of Geoscience and Info-Physics Central South University State Key Laboratory of Ore Deposit Geochemistry Institute of Geochemistry Chinese Academy of Sciences

The Pb-Zn metallogenic district in NW Guizhou Province is an important part of the yun-nan-Sichuan-Guizhou Pb-Zn metallogenic province, and also is one of the most important Pb-Zn producers in china. The hosting rocks of the Pb-Zn deposits are Devonian to Permian carbonate rocks, and the basement rocks are meta-sedimentary and igneous rocks of the Proterozoic Kunyang and Huili groups. The ore minerals are composed of sphalerite, galena and pyrite, and the gangue minerals are include calcite and dolomite. Geology and c-O isotope of these deposits were studied in this paper. The results show that δ13c and δ18O values of hydrothermal calcite, altered wall rocks-dolostone, sedimentary calcite and hosting carbonate rocks range from -5.3‰ to -0.6 ‰ (mean -3.4‰) and +11.3‰ to +20.9 ‰ (mean +17.2‰), -3.0‰ to +0.9 ‰ (mean -1.3‰) and +17.0‰ to +20.8‰ (mean +19.7‰), +0.6‰ to +2.5 ‰ (mean +1.4‰) and +23.4‰ to +26.5 ‰ (mean +24.6‰), and -1.8‰ to +3.9‰ (mean +0.7‰) and +21.0‰ to +26.8‰ (mean +22.9‰), respectively, implying that cO2 in the ore-forming fluids was mainly a result of dissolution of Devonian and carboniferous carbonate rocks. However, it is difficult to evaluate the contribution of sediment de-hydroxylation. Based on the integrated analysis of geology, c and O isotopes, it is believed that the ore-forming fluids of these carbonate-hosted Pb-Zn deposits in this area were derived from multiple sources, including hosting carbonate rocks, Devonian to Permian sedimentary rocks and basement rocks (the Kun-yang and Huili groups). Therefore, the fluids mixing is the main precipitation mechanism of the Pb-Zn deposit in this province.

关键词：铅锌矿床碳酸盐岩碳氧同位素综合地质中国西南同位素地球化学贵州省托管

Structure-based design of conformationally constrained cyclic peptidomimetics to target the MLL1-WDR5 protein–protein interaction as inhibitors of the MLL1 methyltransferase activity

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chinese chemical Letters 2015年第4期26卷 455-458页

作者： Hacer Karatas Shirley y.Lee Elizabeth c.Townsend Fang cao Jing Xu Denzil Bernard Liu Liu yali dou Shaomeng Wang Department of Medicinal chemistry University of Michigan Department of Internal Medicine University of Michigan Department of Pathology University of Michigan comprehensive cancer center University of Michigan Department of Pharmacology University of Michigan

We described herein structure-based design, synthesis and evaluation of conformationally constrained, cyclic peptidomimetics to block the MLL1-WDR5 protein-protein interaction as inhibitors of the MLL1 histone methyltransferase activity. Our study has yielded cyclic peptidomimetics with very high binding affinities to WDR5 （Ki values 〈1 nmol/L） and function as antagonists of the MLL1 histone methyltransferase activity.

关键词： EpigeneticsMLL1 histone methyltransferaseWDRS-MLLI interactionSmall-molecule inhibitorscyclic peptidomemtics

classification of positive solutions to an integral system with the poly-harmonic extension operator

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Science china Mathematics 2018年第9期61卷 1603-1616页

作者： Sufang Tang Jingbo dou School of Statistics Xi'an University of Finance and Economics School of Mathematics and Information Science Shaanxi Normal University

In this paper, we investigate the positive solutions to the following integral system with a polyharmonic extension operator on R^+_n:{u(x)=c_n,a∫_?R_+~n(x_n^(1-a_v)(y)/|x-y|^(n-a))dy,x∈R_+~n,v(y)=c_n,a∫_R_+~n(x_n^(1-a_uθ)(x)/|x-y|^(n-a))dx,y∈ ?R_+~n,where n 2, 2-n 0. This integral system arises from the Euler-Lagrange equation corresponding to an integral inequality on the upper half space established by chen(2014). The explicit formulations of positive solutions are obtained by the method of moving spheres for the critical case κ =n-2+a/n-a,θ =n+2-a/ n-2+a. Moreover,we also give the nonexistence of positive solutions in the subcritical case for the above system.

关键词： integral system poly-harmonic extension method of moving spheres regularity Kelvin transformation

Multi-Objective cooperative Salvo Attack Against Group Target

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Journal of Systems Science & complexity 2018年第1期31卷 244-261页

作者： ZENG Jie dou Lihua XIN Bin School of Automation State Key Laboratory of Intelligent Control and Decision of Complex SystemsBeijing Advanced Innovation Center for Intelligent Robots and Systems Beijing Institute of Technology

This paper proposes a solution for the problem of cooperative salvo attack of multiple cruise missiles against targets in a group. Synchronization of the arrival time of missiles to hit their common target, minimizing the time consumption of attack and maximizing the expected damage to group targets are taken into consideration simultaneously. These operational objectives result in a hierarchical mixed-variable optimization problem which includes two types of subproblems, namely the multi-objective missile-target assignment（MOMTA） problem at the upper level and the time-optimal coordinated path planning（TOcPP） problems at the lower level. In order to solve the challenging problem, a recently proposed coordinated path planning method is employed to solve the TOcPP problems to achieve the soonest salvo attack against each target. With the aim of finding a more competent solver for MOMTA, three state-of-the-art multi-objective optimization methods（MOMs）,namely NSGA-II, MOEA/D and DMOEA-εc, are adopted. Finally, a typical example is used to demonstrate the advantage of the proposed method. A simple rule-based method is also employed for comparison. comparative results show that DMOEA-εc is the best choice among the three MOMs for solving the MOMTA problem. The combination of DMOEA-εc for MOMTA and the coordinated path planning method for TOcPP can generate obviously better salvo attack schemes than the rule-based method.

关键词： coordinated path planning missile-target assignment multi-missile salvo attack multiobjective optimization

Effects of Tangential Velocity Distribution on Flow Stability in a Draft Tube

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Journal of Thermal Science 2014年第5期23卷 446-453页

作者： dou Huashu NIU Lin cAO Shuliang Faculty of Mechanical Engineering and Automation Zhejiang Sci-Tech University Department of Thermal Engineering Tsinghua University

Numerical simulations of the flow in the draft tube of a Francis turbine are carried out in order to elucidate the effects of tangential velocity on flow *** of the location of the maximum tangential velocity is explored considering the equality of the total energy at the inlet of the draft *** is found that the amplitude of the pressure fluctuation decreases when the location of the maximum of the tangential velocity moves from the centre to the wall on the cross ***,the stability of the flow in the draft tube increases with the moving of the location of the maximum tangential ***,the relative hydraulic loss increases and the recovery coefficient of the draft tube decreases slightly.

关键词： draft tube vortex characteristics numerical prediction velocity distribution