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Acta Mechanica Sinica 2024年第4期40卷 125-135页

作者：巩绪安马兴宇姜楠 Department of Mechanics School of Mechanical EngineeringTianjin UniversityTianjin300354China National Key Laboratory of Aerodynamic Noise Control China Aerodynamics Research and Development CenterSichuan621000China National Key Laboratory of Science and Technology on Aerodynamic Design and Research School of AeronauticsNorthwestern Polytechnical UniversityXi’an710072China State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong UniversityChengdu610031China

本文在二维机翼上安装了仿生的覆羽结构,在5.0×105的雷诺数下研究它们控制前缘流动分离的效果.覆羽是指覆盖在鸟类翅膀上的多排短而柔软的带有锯齿状尖端的羽毛.它们覆盖在长而硬的飞羽边缘,使鸟的翅膀保持流线型.当流动分离发生时... 详细信息

本文在二维机翼上安装了仿生的覆羽结构,在5.0×105的雷诺数下研究它们控制前缘流动分离的效果.覆羽是指覆盖在鸟类翅膀上的多排短而柔软的带有锯齿状尖端的羽毛.它们覆盖在长而硬的飞羽边缘,使鸟的翅膀保持流线型.当流动分离发生时,这些柔性锯齿形的人工覆羽在来流的激励下能够自适应地变形和颤振.在风洞实验中,本文使用高时间分辨率的粒子图像测速仪(PIV)来测量机翼上表面的速度场,并使用热线风速仪来测量尾流中的高频湍流脉动.安装在20%弦长处的人工覆羽在前缘分离流的激励下会自适应地大幅翻转.安装在80%弦长处的覆羽则会被尾缘卷起的脱落涡向上抬起,并在准平衡状态下轻微摆动.这两类人工覆羽均能够有效地控制流动分离,并减小尾流的湍流脉动强度.

关键词：流动分离风洞实验分离流湍流脉动高时间分辨率热线风速仪高雷诺数锯齿形

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Anti-Disturbance Formation Control of Quadrotor UAVs Based on Terminal Sliding Mode Control

Anti-Disturbance Formation Control of Quadrotor UAVs Based o...

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Chinese Automation Congress (CAC)

作者： Ying Xin Hao Ni Zihao Huang Yongning He Sigang Xia Intelligent Flight Control Technology Research and Development Center Shanghai Aerospace Control Technology Institute Shanghai China Electrical system laboratory Shanghai Institute of Mechanical and Electrical Engineering Shanghai China

In this paper, the anti-disturbance formation flight control of quadrotor UAVs system is realized based on terminal sliding mode control. The generalized error state is designed for each quad-rotor UA V, based on which the formation control target is proposed. In order to achieve the goal of anti-disturbance formation control, a formation controller based on terminal sliding mode control is designed. Finally, the general error states of all quadrotor UAVs converge to zero to achieve the desired formation. Finally, a simulation example is given to verify the effectiveness of the proposed algorithm.

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A fast calculation method for three-impulse contingency return trajectory during the near-moon phase based on differential algebra

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Chinese Journal of Aeronautics 2025年第4期 290-308页

作者： Lin LU Haiyang LI Tianshan DONG Wanmeng ZHOU College of Aerospace Science and Technology National University of Defense Technology Hunan Key Laboratory of Intelligent Planning and Simulation for Aerospace Missions Beijing Institute of Spacecraft System Engineering China Astronaut Research and Training Center

Aimed at the demand of contingency return at any time during the near-moon phase in the manned lunar landing missions,a fast calculation method for three-impulse contingency return trajectories is ***,a three-impulse contingency return trajectory scheme is presented by combining the Lambert transfer and maneuver at the special ***,a calculation model of three-impulse contingency return trajectories is ***,fast calculation methods are proposed by adopting the high-order Taylor expansion of differential algebra in the twobody trajectory dynamics model and perturbed trajectory dynamics ***,the performance of the proposed methods is verified by numerical *** results indicate that the fast calculation method of two-body trajectory has higher calculation efficiency compared to the semi-analytical calculation method under a certain accuracy *** to its high efficiency,the characteristics of the three-impulse contingency return trajectories under different contingency scenarios are further analyzed *** findings can be used for the design of contingency return trajectories in future manned lunar landing missions.

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A control system in a micro cone-beam CT machine

A control system in a micro cone-beam CT machine

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Biomedical Engineering International Conference (BMEiCON)

作者： Atthasak Kiang-Ia Sathid Rukkhong Tanapon Srivongsa Kittipong Kasantikul Chalinee Thanasupsombat Sorapong Aootaphao Saowapak Thongvigitmanee Medical Imaging System Research Team Assistive Technology and Medical Devices Research Center National Science and Technology Development Agency Pathum Thani Thailand

ISBN: (纸本)9781665489041

Images data from the micro cone-beam computed tomography (CBCT) are acquired from a rotation of an object located between an X-ray generator and a flat panel detector; therefore, the rotational position of the motor is very important for image quality of 3D cross-section images. This study focuses on designing the position control of the stepping motor using the motion module, which enhances the control 4-axis motor’s efficiency to optimize and increase the accuracy of motor movement. We designed the stepping motor position control system to control the movement of the micro CBCT system to perform ten circular rotations in a single scanning process. A phantom was used to verify the rotational image accuracy by considering the image at the same position each round. Comparison of the motor movement with and without the motion module showed slight differences of projection images causing artifacts in cross-section images. Thus, the design of the rotation position control using the motion module circuit yielded good performance in terms of precision and rotational accuracy on the CBCT.

关键词： Image quality Three-dimensional displays Computed tomography Position control Process control Phantoms Detectors

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A low complexity JPEG coding system

A low complexity JPEG coding system

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Neural Networks, Information and Communication Engineering (NNICE), International Conference on

作者： Xing Zhang Xiaoqiang Zhang Xinxing Zheng Mingyu Xu School of Integrated Circuit Anhui Polytechnic University Wuhu China Anhui Automotive Display Integrated System Engineering Research Center Wuhu China School of Information and Artificial Intelligence Wuhu Institute of Technology Wuhu China Wuhu Automotive Intelligent Product Development and Application Engineering Technology Research Center Wuhu China

In the field of image compression, the traditional JPEG encoding uses a lot of multiplication operations in the discrete cosine transform and quantization. In order to reduce the computational complexity and meet the real-time requirements of the system, a low-complexity 8*8 orthogonal transformation matrix is proposed for low-bit-rate image compression, which only contains 0 and 1, without multiplication and shift operations. In addition, an approximate quantization table is designed to replace the traditional quantization table, in which addition and multiplication are not required, only shift operations are required. The results show that the image quality obtained by approximate quantization is basically the same as that of standard quantization, and the proposed coding framework can also be implemented on FPGA.

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Biodiversity conservation and ecological restoration of vulnerable ecosystems in the Anthropocene

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Journal of Plant Ecology 2024年第5期17卷 1-4页

作者： Zhonghua Ning Tian Xie Xinxin Wang Zhenchang Zhu Cong Chen Baoshan Cui Key Laboratory of Ecological Protection in the Yellow River Basin of National Forestry and Grassland Administration School of Ecology and Nature ConservationBeijing Forestry UniversityBeijing 100083China State Key Joint Laboratory of Environmental Simulation and Pollution Control School of EnvironmentBeijing Normal UniversityBeijing 100875China Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering National Observations and Research Station for Wetland Ecosystems of the Yangtze EstuarySchool of Life ScienceFudan UniversityShanghai 200433China School of Ecology Environment and ResourcesGuangdong University of TechnologyGuangzhou 510006China Research and Development Center for Watershed Environmental Eco-engineering Advanced Institute of Natural SciencesBeijing Normal UniversityZhuhai 519087China

This editorial summarizes the contributions to the Special Issue Biodiversity conservation and ecological restoration of vulnerable ecosystems in the Anthropocene',established under the Journal of Plant Ecology.

关键词： Biodiversity ecosystems restoration

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Cyber-Attack Risk Assessment and Prevention Strategy of Substations Based on Dynamic Attack and Defense Game 3

Cyber-Attack Risk Assessment and Prevention Strategy of Subs...

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3rd Power system and Green Energy Conference, PSGEC 2023

作者： Lin, Feng Mei, Yong Zhu, Yihua Chang, Dongxu Liu, Ren Guo, Hengdao China Southern Power Grid Power Dispatch and Control Center GuangZhou China Electric Power Research Institute China Southern Power Grid State Key Laboratory of Hvdc GuangZhou China Electric Power Research Institute China Southern Power Grid National Energy Power Grid Technology R&d Centre GuangZhou China China Southern Power Grid Csg Key Laboratory for Power System Simulation GuangZhou China Guangdong Provincial Key Laboratory of Intelligent Operation Control for New Energy Power System GuangZhou China

ISBN: (纸本)9798350340099

With the improvement of the informatization of the power system, the risk of cyber attack is also increasing. This paper proposes a risk assessment and prevention strategy for cyber attack against substations. Firstly, the cyber attack against substations are modeled based on the game theory of dynamic attack and defense. Secondly, an improved OPA (ORNL-PSERC-Alaska) model is utilized to analyze the cascade failure after cyber attacks and quantify the load loss of power system. Finally, a preventive strategy which can mitigate the expectation load loss caused by cyber attack against substations is put forward. simulation experiments were conducted to validate the effectiveness of the proposed method. © 2023 IEEE.

关键词： Risk assessment

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Assimilation of Radar and Cloud-to-Ground Lightning Data Using WRF-3DVar Combined with the Physical Initialization Method——A Case Study of a Mesoscale Convective system

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Journal of Meteorological research 2021年第2期35卷 329-342页

作者： Ruhui GAN Yi YANG Qian XIE Erliang LINi Ying WANG Peng LIU Key Laboratory of Climate Resource Development and Disaster Prevention in Gansu Province College of Atmospheric SciencesLanzhou UniversityLanzhou 730000 Research Center for the Development of the Earth System Model of Lanzhou University College of Atmospheric SciencesLanzhou UniversityLanzhou 730000 School of Marine Science Nanjing University of Information Science&TechnologyNanjing 210044

Radar data, which have incomparably high temporal and spatial resolution, and lightning data, which are great indicators of severe convection, have been used to improve the initial field and increase the accuracies of nowcasting and short-term forecasting. Physical initialization combined with the three-dimensional variational data assimilation method(PI3 DVarrh) is used in this study to assimilate two kinds of observation data simultaneously, in which radar data are dominant and lightning data are introduced as constraint conditions. In this way, the advantages of dual observations are adopted. To verify the effect of assimilating radar and lightning data using the PI3 DVarrh method, a severe convective activity that occurred on 5 June 2009 is utilized, and five assimilation experiments are designed based on the Weather research and Forecasting(WRF) model. The assimilation of radar and lightning data results in moister conditions below cloud top, where severe convection occurs;thus, wet forecasts are generated in this *** results show that the control experiment has poor prediction accuracy. Radar data assimilation using the PI3 DVarrh method improves the location prediction of reflectivity and precipitation, especially in the last 3-h prediction, although the reflectivity and precipitation are notably overestimated. The introduction of lightning data effectively thins the radar data, reduces the overestimates in radar data assimilation, and results in better spatial pattern and intensity predictions. The predicted graupel mixing ratio is closer to the distribution of the observed lightning,which can provide more accurate lightning warning information.

关键词： radar data lightning data data assimilation physical initialization combined with the three-dimensional variational data assimilation method(PI3DVarrh) convection Weather research and Forecasting(WRF)

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Digit-Module Decoupling Platform Architecture for Safety Automation Equipment

Digit-Module Decoupling Platform Architecture for Safety Aut...

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Power and Electrical Engineering (ACPEE), 5th Asia Conference on

作者： Xinghua Chen Jinchang Chen Hao Yu Yuanyuan Ning Lixian Huang System Analysis Department Power Dispatching and Control Center of Guangdong Power Grid Guangzhou Research and Development Department Jiangsu Huaruitai Technology Co. Ltd. Nanjing

The existing safety automation equipment are designed to perform in an integrated and centralized way, with the strategy of one device corresponding to one function, and with strong coupling inside the equipment, which brings the problems of repeatability and complexity in management, increases the management workload, and is difficult to standardize the management; Therefore, it is necessary to design the platform architecture for the safety automation equipment from top to bottom, adopt new rapid link technology and establish common standard communication transmission protocol to standardize the consistency of data transmission; to isolate the collection module and the digital part in terms of hardware part to achieve hardware decoupling; and to divide the basic strategy logic and advanced strategy logic of functional strategy in terms of digital part, to adopt independent hardware intelligent plug-in for special strategy software, form the minimum basic function Amass Unit, set up the data center of equipment, adopt virtual agent mechanism, so as to achieve software decoupling, and form the digit-module decoupling platform architecture of "high integration and loose coupling" for safety automation equipment, which will provide the key technical basis for the standardized management of safety automation equipment.

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Breaking the Resource Curse: The Impact of Digital Economy on the Sustainable Transformation of Resource-Based Cities

SSRN

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SSRN 2024年

作者： Zhou, Jianping Xu, Weixiang Yan, Dan School of Economics Zhejiang University of Technology China Institute for Industrial System Modernization Zhejiang University of Technology China School of Public Administration Zhejiang University of Technology China Research Center for Transition and Development of Resource-exhausted Cities Hubei Normal University Huangshi435002 China

Resource-based cities (RBC) primarily depend on the extraction and processing of natural resources, resulting in a relatively simplistic economic structure. However, the emergence of the digital economy (DIGITAL) brings a multitude of opportunities, such as economic diversification and sustainable development. In order to examine the potential of DIGITAL to overcome the resource curse, further investigation is required. Based on data from 115 RBC in China spanning 2011 to 2019, this study examines the influence of digital economic development on the sustainable transformation of these cities. The study conducts robustness and heterogeneity tests, and concludes that digital economic development is a key driver of the sustainable transformation of Resource-based cities (STRBC). This conclusion is further supported by various robustness tests. Urban economic efficiency, functional division of labor in urban areas and vitality of innovation and entrepreneurship are the channels through which DIGITAL contributes to STRBC. Governmental environmental concern can enhance the role of DIGITAL in promoting STRBC. Furthermore, variances in the role of DIGITAL are influenced by factors such as the type of city and spatial scale. © 2024, The Authors. All rights reserved.

关键词： Sustainable development

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