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A non-probabilistic reliability topology optimization method based on aggregation function and matrix multiplication considering buckling response constraints

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Applied Mathematics and Mechanics(English Edition) 2024年第2期45卷 321-336页

作者： Lei WANG Yingge LIU Juxi HU Weimin CHEN Bing HAN Institute of Solid Mechanics School of Aeronautic Science and EngineeringBeihang UniversityBeijing 100191China Aircraft and Propulsion Laboratory Ningbo Institute of TechnologyBeihang UniversityNingbo 315100Zhejiang ProvinceChina State Key Laboratory of Navigation and Safety Technology Shanghai Ship and Shipping Research InstituteShanghai 200135China National Engineering Research Center of Ship&Shipping Control System Shanghai Ship and Shipping Research InstituteShanghai 200135China

A non-probabilistic reliability topology optimization method is proposed based on the aggregation function and matrix *** expression of the geometric stiffness matrix is derived,the finite element linear buckling analysis is conducted,and the sensitivity solution of the linear buckling factor is *** a specific problem in linear buckling topology optimization,a Heaviside projection function based on the exponential smooth growth is developed to eliminate the gray *** aggregation function method is used to consider the high-order eigenvalues,so as to obtain continuous sensitivity information and refined structural *** cyclic matrix programming,a fast topology optimization method that can be used to efficiently obtain the unit assembly and sensitivity solution is *** maximize the buckling load,under the constraint of the given buckling load,two types of topological optimization columns are *** variable density method is used to achieve the topology optimization solution along with the moving asymptote optimization *** vertex method and the matching point method are used to carry out an uncertainty propagation analysis,and the non-probability reliability topology optimization method considering buckling responses is developed based on the transformation of non-probability reliability indices based on the characteristic ***,the differences in the structural topology optimization under different reliability degrees are illustrated by examples.

关键词： buckling topology optimization aggregation function uncertainty propagation analysis non-probabilistic reliability

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NUMERICAL INVESTIGATION ON DIRECT CONTACT CONDENSATION CHARACTERISTICS OF STEAM INJECTION INTO COLD-WATER PIPE UNDER HEAVING CONDITION 30

NUMERICAL INVESTIGATION ON DIRECT CONTACT CONDENSATION CHARA...

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30th International Conference on Nuclear Engineering, ICONE 2023

作者： Wang, Zhiwei He, Yanping Duan, Zhongdi Huang, Chao Liu, Shiwen State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University Shanghai200240 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu China

ISBN: (纸本)9784888982566

Direct contact condensation (DCC) is widely appeared in the nuclear power plants and will lead to serious temperature and pressure fluctuations. For ocean nuclear power plants, the DCC is inevitably affected by the sea conditions, such as rolling, heaving motion. In this study, the integration of volume of fluid model (VOF) and condensation model is adopted to simulate the DCC characteristics under heave conditions. The interfacial heat and mass transfer are calculated by user-defined functions (UDF). The additional inertial force method is used to describe the heave motion. First, the DCC numerical model under heave motion is validated by the experimental data, which coincides well with the experiment results. Then, the characteristics of DCC under different heave parameters are numerically studied. The results show that the average condensation rate increases with an increase in heave amplitude, decreases with an increase in heave period. This is mainly because the heave motion will cause the liquid phase to impact the upper pipe wall, and increasing the contact area of vapor and subcooled water. The pressure oscillations induced by DCC are more complicated under heaving conditions. With heave period continuing to change, the formation mechanisms of the pressure peak are different. When the heave period is relatively small, the pressure peak is mainly induced by the acceleration of water phase under high frequency heaving motion. With an increase in the heave period, the heaving motion accelerated the formation of isolated steam bubble, and caused the condensation induced water hammer (CIWH) events, which in turn induced the pressure peak. In addition, the pressure peak is proportional to the heave amplitude. In summary, the direct contact condensation characteristics are more sensitive to the heave period under heaving conditions. These qualitative conclusions may serve as a reference for direct contact condensation simulations under heaving conditions. © 2023 by

关键词： Nuclear power plants

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CRFENet: Cross-Spectral Stereo Matching Network Exploiting Reciprocal Feature Evolution 2nd

CRFENet: Cross-Spectral Stereo Matching Network Exploiting R...

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2nd International Conference on the Frontiers of robotics and Software Engineering, FRSE 2024

作者： Li, Yangqin Zhang, Guanghui Zhu, Dongchen Shi, Wenjun Wang, Lei Zhang, Xiaolin Shanghai Institute of Microsystem and Information Technology Bionic Vision System Laboratory State Key Laboratory of Transducer Technology Chinese Academy of Sciences Shanghai200050 China University of Chinese Academy of Sciences Beijing100049 China School of Information Science and Technology ShanghaiTech University Shanghai201210 China

ISBN: (纸本)9789819630127

Cross-spectral stereo matching opens up a new route for disparity estimation in low-light scenes. However, the variations in light absorption and reflection properties for objects at different wavelengths create substantial domain gaps in cross-spectral image pairs. Accurately matching pixel pairs with significant domain gaps remains challenging. In this work, we propose a novel lightweight cross-spectral stereo matching network, dubbed CRFENet, exploiting reciprocal feature evolution. It enables the complementary evolution of the disparity prediction network and spectral translation network. To facilitate feature interactions between different domains to improve disparity results in regions with significant domain gaps, we design a domain mutual rail (DMR) module, which integrates monocular spectral and binocular cross-spectral features. Furthermore, we present a domain gap consistency constraint and corresponding confidence-weighted loss function, which aim to alleviate the matching challenge in regions with significant domain gaps through decoupling domain gap and disparity. Experimental results indicate that our CRFENet achieves state-of-the-art performance on the PittsStereo RGB-NIR and DrivingStereo datasets, especially for challenging regions with significant domain gaps. Besides, the model parameters are only 3.6M, which means high practicality. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025.

关键词： Stereocenters

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Remote,selective,and in situ manipulation of liquid droplets on a femtosecond laser-structured superhydrophobic shape-memory polymer by near-infrared light

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Science China Chemistry 2021年第5期64卷 861-872页

作者： Xue Bai Jiale Yong Chao Shan Yao Fang Xun Hou Feng Chen State Key Laboratory for Manufacturing System Engineering and Shaanxi Key Laboratory of Photonics Technology for Information School of Electronic Science and EngineeringXi’an Jiaotong UniversityXi’an 710049China

Droplet manipulation plays a significant role in the fields of biomedical detection,microfluidics,and chemical ***,it still remains a great challenge to simultaneously achieve remote,selective,and in situ droplet manipulation on the same ***,Fe_(3)O_(4)nanoparticles were doped in a shape-memory polymer(SMP)to prepare a photothermal-responsive Fe_(3)O_(4)-SMP composite which showed remarkable near-infrared(NIR)light-triggered shape-memory *** micropillar array was constructed on such Fe_(3)O_(4)-SMP composite through femtosecond laser microfabrication and fluoroalkylsilane *** surface wettability of the as-prepared surface can transform from a low-adhesive sliding state to a high-adhesive pinning state as the micropillars are deformed by ***,the deformed micropillars can stand up and restore to their original morphology under remote NIR light irradiation,resulting in the reversible and repeatable recovery of the ultralow-adhesive *** such light-triggered wettability switching,the droplets pinning on the sample surface can be remotely,selectively,and in situ ***,the superhydrophobic Fe_(3)O_(4)-SMP surface is successfully applied in lossless liquid transfer,selective droplet release,and droplet-based *** as-fabricated superhydrophobic surfaces with NIR light-controlled reversible wettability will hold great promise in the fields of liquid manipulation,lab-on-a-chip,and microfluidics.

关键词： droplet manipulation superhydrophobicity shape-memory polymer femtosecond laser light responsive

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High Temperature and Electric Field Dependence of Resistivity in Impregnated Polypropylene Film 10

High Temperature and Electric Field Dependence of Resistivit...

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10th International Forum on Electrical Engineering and Automation, IFEEA 2023

作者： Zhang, Xinghui Zeng, Fanqiu Guo, Shaowei Xing, Zhaoliang Zhang, Chong Gao, Chunjia Qi, Bo Cui, Huize Beijing China North China Electric Power University State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources Beijing China State Grid Smart Grid Research Institute Co. Ltd. State Key Laboratory of Advanced Power Transmission Technology Beijing China State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources Beijing China

ISBN: (纸本)9798350309379

Biaxially oriented polypropylene film (BOPP) and benzyltoluene are the dominant insulating media in high-voltage capacitors. In order to investigate the electrical performance of impregnated film materials, this paper builds a polypropylene film volume resistivity test platform, which conducts tests for five thicknesses of the film to obtain the change rules of impregnated film in different temperature and field strength. Test result shows that: 1) Volume resistivity decreased after impregnation. At room temperature, the volume resistivity of 13 μm impregnated film decreases from 1.83×1016 Ω m to 1.71×1016 Ω m. 2) Impregnated film is significantly affected by high temperature and electric field. When field strength increases from 10 MV/m to 100 MV/m at room temperature, volume resistivity of the impregnated film decreases from 7% to 17% compared with the dry film. When temperature increases to 353 K and field strength increases to 300 MV/mm, volume resistivity of the impregnated film decreases by more than 30%. 3) The variation of volume resistivity of polypropylene film with temperature and field strength can be described by hopping model. At room temperature, the electron hopping distance increases from 1.3 nm to 1.4 nm, and at 353 K, impregnation makes electron hopping distance increase from 1.8 nm to 2.8 nm. The study of the change rules of the impregnated film at high temperatures and fields can help to establish a more accurate capacitor electro-thermal model. © 2023 IEEE.

关键词： Biaxially oriented polypropylene film impregnation volume resistivity

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Active Voltage Control Method of Distributed Photovoltaic Based on Safe Deep Reinforcement Learning 9th

Active Voltage Control Method of Distributed Photovoltaic Ba...

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9th Purple Mountain Form on Smart Grid Protection and Control, PMF 2024

作者： Zeng, Yi Zhou, Yi Lu, Jixiang Zhou, Liangcai Tang, Ningkai Li, Hong Jiangsu Nanjing211106 China East China Branch of State Grid Corporation Shanghai200120 China State Key Laboratory of Technology and Equipment for Defense Against Power System Operational Risks Jiangsu Nanjing211106 China

ISBN: (纸本)9789819616701

With the rapid development of distributed photovoltaic (PV) technology in China, the issues of voltage limit violation and fluctuation caused by the large-scale penetration of distributed PVs into the distribution network have become increasingly prominent. Traditional voltage control methods are limited by solution speed and quality. While conventional deep reinforcement learning methods lack the necessary constraints during action exploration to ensure safety. Therefore, an active voltage control method of distributed PV based on safe deep reinforcement learning is proposed. Firstly, the voltage control problem is modeled as a distributed partially observable Markov decision process. Secondly, a safety layer based on the integration of "mechanism (mathematical computation) and knowledge (gird dispatch rules, etc.)" is added for agent design. Test results on the modified IEEE 33-bus case show that the proposed method can control the voltage within safe limits, significantly reduce voltage deviation and network losses, and improve the voltage safety of the power system. © state Grid Electric Power 2025.

关键词： Markov processes

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Low-gain Control Strategy for Robot Manipulators Based on Sparse Feature Learning Dynamics with an Application to Collision Detection

Low-gain Control Strategy for Robot Manipulators Based on Sp...

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IEEE International Workshop on Safety, Security, and Rescue robotics (SSRR)

作者： Chenglong Yu Zhiqi Li Weixin Chou Hong Liu State Key Laboratory of Robotics and System Harbin Institute of Technology China

ISBN: (纸本)9781665456814

Recently, with the robotic technique developing toward precision and intelligence, robots have been used more widely in human life and production. As a common feature in the foreseen applications, robots should be able to detect unexpected collisions while ensuring dynamic accuracy, so as to improve safety at work. In the previous model-based collision detection solution, most methods assume that the robot dynamic model is complete and accurate. Unfortunately, reliable robot dynamics is hard to obtain due to model uncertainties, assembly errors, and the lack of information provided by manufacturers. This paper proposed a novel low-gain control strategy based on sparse feature learning dynamics. Firstly, without considering the physical structure parameters, the dynamics was learned directly via the data-driven technique. Secondly, according to the learned accurate dynamics, a model-based low-gain controller was designed to ensure control performance while avoiding excessive unspecified force. Finally, using this control strategy, sensorless collision detection was realized in a 7-DOF manipulator and the performance of the proposed method was evaluated.

关键词： Representation learning Service robots Dynamics Force Robot sensing systems Safety Security

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A review:Research on corrosive sulphur in electrical power equipment

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High Voltage 2022年第2期7卷 209-221页

作者： Yuan Yuan Xue Gao Jiang Zhou Guoyong Liu Xiongwei Kuang Lijun Yang Ruijin Liao College of Materials Science and Engineering Chongqing UniversityChongqingChina The State Key Laboratory of Power Transmission Equipment&System Security and New Technology Chongqing UniversityChongqingChina

Corrosive sulphur has been commonly regarded as an enormous threat to electrical power equipment in recent *** sulphide(Cu2S)deposition on the insulating oil and paper insulation caused by sulphur corrosion will bring about insulation deteriorations or failures in power transformers and shunt reactors.A large number of experiments have been carried out to investigate sulphur corrosion and some measures have been come up to solve this issue such as replacement of insulating oil,chemical removal of corrosive sulphur and the addition of passivator and so ***,there has not been a perfect method to work out this problem completely,and the phenomenon of sulphur corrosion still *** paper intends to provide thorough information of corrosive sulphur in power equipment and give detailed explanations about its corrosion mechanism,hazards and control measures,which is supposed to offer a reference for subsequent researchers.

关键词： corrosion sulphur electrical

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Optical mode enabled manipulation of topological phase in waveguide-based scattering networks

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Physical Review B 2024年第7期110卷 075424-075424页

作者： Changyu Zhou Zhenwei Xie Ting Lei Yao Zhang Qinmiao Chen Xiaocong Yuan Nanophotonics Research Center Institute of Microscale Optoelectronics & State Key Laboratory of Radio Frequency Heterogeneous Integration State Key Laboratory on Tunable Laser Technology Ministry of Industry and Information Technology Key Lab of Micro-Nano Optoelectronic Information System

In a topological system with an edge, the number of edge states is typically determined by the bulk topological invariant, as per the well-established bulk-boundary correspondence. However, anomalous topological edge states can arise in periodically driven Floquet systems even when the bulk Chern number is zero. A topological invariant (winding number) has been introduced to establish the appropriate bulk-boundary correspondence in such systems. Nevertheless, manipulating the topological properties of systems, whether static or driven, remains a significant challenge. In photonic systems, optical fields with diverse inherent dimensions such as frequency and polarization offer a natural avenue for topological-phase manipulation. In this paper, we present an alternative scheme for switching the topological invariant (winding number) of the system by changing the optical-waveguide mode within an integrated waveguide-based scattering network. With creating a bonding interface, this topological-phase switching facilitates the transmissions of the interface state in different directions. Experimental validation of this concept is demonstrated using a ring-optical-waveguide device. In this paper, we introduce an alternative strategy for tailoring the topological properties of optical systems.

关键词： Nanophotonics Topological effects in photonic systems Topological phase transition Waveguides

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Microseismic observations reveal that internal waves intensify seabed methane release

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Science China Earth Sciences 2024年第10期67卷 3186-3203页

作者： Zhaoyang TIAN Yonggang JIA Junjiang ZHU Tian CHEN Hui WANG Chunsheng JI Chengyu LIU Longyu LU Manchao HE Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering Ocean University of ChinaQingdao 266100China Frontiers Science Center for Deep Ocean Multispheres and Earth System Key Lab of Submarine Geosciences and Prospecting TechniquesMOE and College of Marine GeosciencesOcean University of ChinaQingdao 266100China Guangzhou Marine Geological Survey China Geological SurveyGuangzhou 511458China Shandong Earthquake Agency Jinan 250014China State Key Laboratory for Tunnel Engineering China University of Mining and Technology(Beijing)Beijing 100083China

Internal waves transport material and energy from the upper water column to the deep ocean, disturbing seabed sediments and resulting in phenomena such as seabed erosion and changes in topography. On the northern slope of the South China Sea and in many coastal margins worldwide, the zones with internal wave action closely overlap with areas where natural gas hydrates are present. However, due to significant differences in the spatial and temporal scales, understanding the influence of internal waves on methane releases from deep seabeds is challenging. In this study, in situ observations of seabed microseismicity and internal waves are conducted at water depths of 655 meters and 1450 meters in the Pearl River Canyon of the South China Sea. The microseismicity caused by internal waves and seabed methane releases is identified, and a method to establish the correlation between internal waves and seabed methane releases through the use of microseismic recordings is proposed, aiming to obtain direct observational evidence of internal waves intensifying seabed methane releases. The results show that internal waves and seabed methane releases generate significant microseismic signals, indicating the continuous influence of internal waves on the deep seabed of the northern slope of the South China Sea and revealing active methane release phenomena on the seabed. At both long and short time scales, internal waves increase the frequency of seabed methane releases by 4.2 times and 2.4 times, respectively, while also enhancing the intensity of these releases. These changes are influenced by the alterations in seabed flow velocity, pressure, and temperature that are induced by internal wave activities. This study emphasizes that microseismic signals are effective carriers of information for multiscale geological processes on seabeds and suggests that internal waves exacerbate marine geological hazards and contribute to global climate change by intensifying seabed methane relea

关键词： Internal waves Seabed methane release Microseismic observation Ocean bottom seismometer Northern slope of the South China Sea

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