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Phase field modeling of ferroelastic variant switching in yttria-stabilized t'zirconia with strain gradient elasticity and interface tension

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Science China(Technological Sciences) 2024年第5期67卷 1443-1457页

作者： zhou QianQian WEI YueGuang zhou YiChun YANG Li College of Engineering BIC-ESATPeking UniversityBeijing100871China School of Advanced Materials and Nanotechnology Xidian UniversityXi’an710126China Frontier Research Center of Thin Films and Coatings for Device Applications Academy of Advanced Interdisciplinary ResearchXidian UniversityXi’an710126China

The 6–8 wt%yttria-stabilized zirconia with a tetragonal structure(t’-YSZ)is extensively employed in thermal barrier *** exceptional fracture toughness of t’-YSZ can be attributed to its distinctive ferroelastic toughening *** and interface tension play a critical role in ferroelastic variant switching at the micro-and *** paper presents an original thermodynamically consistent phase field(PF)theory for analyzing ferroelastic variant switching at the micro-and nano-scale of t’-*** theory incorporates strain gradient elasticity using higher-order elastic energy and interface tension tensor via geometric nonlinearity to represent biaxial tension resulting from interface ***,a mixed-type formulation is employed to implement the higher-order theory through the finite element *** an interface in equilibrium,the effects of strain gradient elasticity result in a more uniform distribution of stresses,whereas the presence of interface tension tensor significantly amplifies the stress magnitude at the *** introduction of an interface tension tensor increases the maximum value of stress at the interface by a factor of 4 to *** nucleation and evolution of variants at a pre-existing crack tip in a mono-phase t’-YSZ have also been *** strain gradient elasticity is capable of capturing the size effect of ferroelastic variant switching associated with microstructures in ***,when the grain size approaches that of the specimen,the critical load required for variant switching at the crack tip increases,resulting in greater dissipation of elastic energy during ferroelastic variant ***,the interface tension accelerates the evolution of *** presented framework exhibits significant potential in modeling ferroelastic variant switching at the micro-and nano-scale.

关键词： thermodynamics strain gradient elasticity interface tension phase field method ferroelastic variant switching

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Deep-reinforcement-learning-based UAV autonomous navigation and collision avoidance in unknown environments

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Chinese Journal of Aeronautics 2024年第3期37卷 237-257页

作者： Fei WANG Xiaoping ZHU zhou zhou Yang TANG School of Astronautics Northwestern Polytechnical UniversityXi’an 710072China School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China

In some military application scenarios,Unmanned Aerial Vehicles(UAVs)need to perform missions with the assistance of on-board cameras when radar is not available and communication is interrupted,which brings challenges for UAV autonomous navigation and collision *** this paper,an improved deep-reinforcement-learning algorithm,Deep Q-Network with a Faster R-CNN model and a Data Deposit Mechanism(FRDDM-DQN),is proposed.A Faster R-CNN model(FR)is introduced and optimized to obtain the ability to extract obstacle information from images,and a new replay memory Data Deposit Mechanism(DDM)is designed to train an agent with a better *** training,a two-part training approach is used to reduce the time spent on training as well as retraining when the scenario *** order to verify the performance of the proposed method,a series of experiments,including training experiments,test experiments,and typical episodes experiments,is conducted in a 3D simulation *** results show that the agent trained by the proposed FRDDM-DQN has the ability to navigate autonomously and avoid collisions,and performs better compared to the FRDQN,FR-DDQN,FR-Dueling DQN,YOLO-based YDDM-DQN,and original FR outputbased FR-ODQN.

关键词： Faster R-CNN model Replay memory Data Deposit Mechanism(DDM) Two-part training approach Image-based Autonomous Navigation and Collision Avoidance(ANCA) Unmanned Aerial Vehicle(UAV)

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Oxidation of emerging organic contaminants by in-situ H_(2)O_(2) fenton system

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Green Energy & Environment 2024年第3期9卷 417-434页

作者： Yuqin Ni Chuxiang zhou Mingyang Xing Yi zhou State Environmental Protection Key Lab of Environmental Risk Assessment and Control on Chemical Processes School of Resources&Environmental EngineeringEast China University of Science and TechnologyShanghai200237China Key Laboratory for Advanced Materials and Institute of Fine Chemicals National Engineering Laboratory for Industrial Wastewater TreatmentSchool of Chemistry and Molecular EngineeringEast China University of Science and Technology130 Meilong RoadShanghai200237China Department of Applied Natural Sciences Technische Hochschule LubeckMonkhofer Weg 23923562 LubeckGermany

The existence and risk of emerging organic contaminants(EOCs)have been under consideration and paid much effort to degrade these *** system is one of the most widely used technologies to solve this *** original Fenton system relies on the hydroxyl radicals produced by Fe(Ⅱ)/H_(2)O_(2) to oxidize the organic ***,the application of the Fenton system is limited by its low iron cycling efficiency and the high risks of hydrogen peroxide transportation and *** introduction of external energy(including light and electricity etc.)can effectively promote the Fe(Ⅲ)/Fe(Ⅱ)cycle and the reduction of oxygen to produce hydrogen peroxide in *** review introduces three in-situ Fenton systems,which are electro-Fenton,Photo-Fenton,and chemical *** mechanism,influencing factors,and catalysts of these three in-situ Fenton systems in degrading EOCs are discussed *** review strengthens the understanding of Fenton and in-situ Fenton systems in degradation,offering further insight into the real application of the in-situ Fenton system in the removal of EOCs.

关键词： In-situ H_(2)O_(2)production Fenton Emerging organic contaminants Photocatalysis Electrocatalysis

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修边机器人的夹紧机构优化设计及运动分析

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中国机械工程 2016年第3期27卷 387-390,412页

作者：李峰平张正亚周斯加温州大学浙江省激光加工机器人重点实验室温州325035

针对修边机器人夹紧机构的优化设计开展研究。通过分析夹紧机构的机构组成原理,建立了以夹紧机构工作半径最大化为优化目标,以各转动副位置、支撑底座质量、极限位置、工作半径范围、压杆运动稳定性和驱动杆推程为约束条件的机构优化设... 详细信息

针对修边机器人夹紧机构的优化设计开展研究。通过分析夹紧机构的机构组成原理,建立了以夹紧机构工作半径最大化为优化目标,以各转动副位置、支撑底座质量、极限位置、工作半径范围、压杆运动稳定性和驱动杆推程为约束条件的机构优化设计数学模型。模型验证实验中,以夹持直径d=40cm的圆形塑料制品为例,得到了压杆位移、压杆与驱动杆速率比随驱动杆位移变化的曲线,并对驱动杆的运动速度曲线进行了规划。仿真结果显示,优化及运动分析结果满足设计要求,从而为修边机器人的优化设计与自动控制提供了设计参考。

关键词：修边机器人夹紧机构优化设计运动分析

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SPARSE RECOVERY BASED ON THE GENERALIZED ERROR FUNCTION

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Journal of Computational Mathematics 2024年第3期42卷 679-704页

作者： Zhiyong zhou Department of Statistics and Data Science and Institute of Digital FinanceHangzhou City UniversityHangzhou 310015China

In this paper,we offer a new sparse recovery strategy based on the generalized error *** introduced penalty function involves both the shape and the scale parameters,making it extremely *** both constrained and unconstrained models,the theoretical analysis results in terms of the null space property,the spherical section property and the restricted invertibility factor are *** practical algorithms via both the iteratively reweighted■_(1)and the difference of convex functions algorithms are *** experiments are carried out to demonstrate the benefits of the suggested approach in a variety of *** practical application in magnetic resonance imaging(MRI)reconstruction is also investigated.

关键词： Sparse recovery Generalized error function Nonconvex regularization Itera-tive reweighted Li Difference of convex functions algorithms

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电磁耦合无级变速传动系统

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机械工程学报 2006年第8期42卷 35-39页

作者：罗玉涛周斯加赵克刚黄向东华南理工大学广东省电动汽车研究重点实验室广州510640 广州汽车集团股份有限公司广州510030

分析现有级联式电传动的优缺点,对其进行结构改进,形成一种电磁耦合无级变速传动系统。该系统主要由具有铁心绕组的转子和定子、附加调磁线圈、具有特殊磁极结构的杯形转子、感应式集流器和功率电子控制器等组成。该系统的特点是将级联... 详细信息

分析现有级联式电传动的优缺点,对其进行结构改进,形成一种电磁耦合无级变速传动系统。该系统主要由具有铁心绕组的转子和定子、附加调磁线圈、具有特殊磁极结构的杯形转子、感应式集流器和功率电子控制器等组成。该系统的特点是将级联式电传动与电磁滑差耦合式机械传动结合为一体,并加上非接触旋转输电,形成原动机的功率分汇流,配以变频与调磁相结合的调速手段,构成拓扑布局紧凑、调控性能优良、运转可靠的无级变速系统。经理论分析可知,系统在保持与常规电传动相当的宽广无级变速范围的同时,总体效率得到提高。系统在内燃机式汽车上使用时,可省去主离合器及发动机起动机等部件,配以储能电池组后,可以作为多能源动力总成直接应用于混合动力电动汽车上。

关键词：电磁耦合无级变速传动系统

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基于引文分析法的学科关联性实证研究——以H大学工程科学为例

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煤炭高等教育 2021年第2期39卷 1-9页

作者：周思佳河海大学水科学研究院综合科江苏南京210098

通过ESI数据库中的论文数据,基于引文分析法对H大学的优势学科工程科学开展学科关联性研究,发现工程科学是支撑其自身发展的主要学科,环境/生态学、地球科学、计算机科学、材料科学、物理学、化学和数学与工程科学互生互长。工程科学的... 详细信息

通过ESI数据库中的论文数据,基于引文分析法对H大学的优势学科工程科学开展学科关联性研究,发现工程科学是支撑其自身发展的主要学科,环境/生态学、地球科学、计算机科学、材料科学、物理学、化学和数学与工程科学互生互长。工程科学的发展吸纳了全部22个学科的学科知识,而对分子生物与遗传学、免疫学与精神病学/心理学这三个学科的发展无任何助力作用。为此,对高校的交叉学科建设提出三个建议:夯实基础,重视优势学科建设;挖掘潜力,关注传统学科交叉;力争破零,注重弱势学科协同。

关键词：引文分析学科关联性实证研究

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Emergent Geometry of KP Hierarchy

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Acta Mathematica Sinica,English Series 2024年第1期40卷 3-25页

作者： Jian zhou Department of Mathematical Sciences Tsinghua UniversityBeijng 100084P.R.China

We explain how to construct a quantum deformation of a spectral curve associated to a tau-function of the KP *** construction is applied to Witten-Kontsevich tau-function to give a natural explanation of some earlier ... 详细信息

关键词： KP hierarchy tau-functions spectral curves

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The dry-hot feedback between soil moisture and atmosphere and the accelerated global warming

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Science China Earth Sciences 2024年第3期67卷 890-891页

作者： Tianjun zhou State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics(LASG) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China

Greenhouse gas (GHG) emissions have been increasing due to human activities since the Industrial Revolution, resulting in continuous warming of the global climate system and significant drought over a large parts of global land, both have shown a non-linear growth trend in recent decades(Berg et al., 2017;zhou et al., 2019;IPCC, 2021).

关键词： warming moisture drought

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Inverse aerodynamic design for distributed propulsion wing with expected circulation distribution

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CHINESE JOURNAL OF AERONAUTICS 2024年第9期37卷 206-223页

作者： Sun, Pengbo zhou, zhou Li, Xu Wang, Kelei Northwestern Polytech Univ Sch Aeronaut Xian 710072 Peoples R China

Distributed Propulsion Wing (DPW) technology offers significant advantages in terms of flight energy savings, but the strong aerodynamic coupling between the propulsive internal flow and aerodynamic external flow brings significant design challenges. As the primary DPW profile design is of great significance, this paper proposes a hybrid method to solve the inverse problem mainly based on the formula relationship between the required aerodynamic loads and the profile shape, which is more direct and instructive compared with traditional parametric iterative methods. The aerodynamic characteristics are described by the circulation distribution in the Fourier series form, then the mean camber line of the profile is solved through the re-derived airfoil theory considering disk's influence. Further CFD correction methods are also proposed. To validate the effectiveness and feasibility of the proposed hybrid inverse method, several DPW profile design tests are then conducted. Finally, the relationship between 2D and realistic 3D unit shape is also researched. The results show that the proposed inverse design method has great accuracy and convergence speed in the design tests, and shows good robustness against changes of the design parameters. The 2D profile shape and the actual 3D shape of DPW unit can establish an aerodynamicpropulsion equivalent relationship based on the same internal mass fluxes. (c) 2024 Production and hosting by Elsevier Ltd. on behalf of Chinese Society of Aeronautics and Astronautics. This is an open access article under the CC BY-NC-ND license (http://***/ licenses/by-nc-nd/4.0/).

关键词： Inverse problem Aerodynamic load Fourier series Flux FLOW SIMULATION SHAPE DESIGN HYBRID OPTIMIZATION

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