检索结果-内蒙古大学图书馆

Hohmann transfer via constrained optimization

Frontiers of Information Technology & Electronic engineering 2018年第11期19卷 1444-1458页

作者： Li XIE Yi-qun ZHANG Jun-yan XU State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources School of Control and Computer EngineeringNorth China Electric Power UniversityBeijing 102206China Beijing Institute of Electronic Systems Engineering Beijing 100854China

Inspired by the geometric method proposed by Jean-Pierre MAREC, we first consider the Hohmann transfer problem between two coplanar circular orbits as a static nonlinear programming problem with an inequality constraint. By the Kuhn-Tucker theorem and a second-order sufficient condition for minima, we analytically prove the global minimum of the Hohmann transfer. Two sets of feasible solutions are found: one corresponding to the Hohmann transfer is the global minimum and the other is a local minimum. We next formulate the Hohmann transfer problem as boundary value problems, which are solved by the calculus of variations. The two sets of feasible solutions are also found by numerical examples. Via static and dynamic constrained optimizations, the solution to the Hohmann transfer problem is re-discovered, and its global minimum is analytically verified using nonlinear programming.

关键词： Hohmann transfer Nonlinear programming Constrained optimization Calculus of variations

来源：评论

学校读者我要写书评

暂无评论

Enhancing heat dissipation and temperature uniformity of microchannel heat sinks using fractal gradient honeycomb-reverse Tesla valve configuration

引用

Case Studies in Thermal engineering 2025年 72卷

作者： Chun-Yu Chen Min Yang Yuanyuan Li Gui Lu School of Energy Power and Mechanical Engineering North China Electric Power University Beijing 102206 China State Key Laboratory of Space Thermal Control Technology Beijing Institute of Spacecraft System Engineering China Academy of Space Technology Beijing 100094 China

This study introduces a fractal gradient honeycomb-reverse Tesla valve configuration (HC-RTV-GD) to enhance heat transfer and temperature uniformity in high-flux thermal management systems. Through comparative analysis with conventional Tesla valves and honeycomb structures, the HC-RTV-GD leverages hierarchical bifurcation and controlled turbulence generation to achieve superior heat transfer performance. At high Reynolds numbers, the design significantly reduces thermal resistance and suppresses maximum wall temperatures while flattening longitudinal temperature gradients, mitigating thermal stress risks. The improved temperature uniformity stems from gradient-driven flow redistribution, which minimizes stagnant zones and sustains coolant velocity in secondary channels. Thermal improvements come with hydraulic trade-offs: the gradient geometry amplifies flow resistance through localized vortices, elevating pressure drop and friction coefficients compared to conventional designs. Performance evaluation confirms the HC-RTV-GD’s viability exclusively in high-flux scenarios, where heat transfer gains outweigh pumping penalties. A neural network-enhanced optimization framework further identifies optimal coolant parameters, balancing thermal and hydraulic efficiency. The HC-RTV-GD advances cooling system design by strategically combining geometric complexity with turbulence control, prioritizing thermal uniformity in extreme heat flux environments.

关键词： Temperature uniformity Fractal gradient Honeycomb-reverse Tesla valve NSGA-II

来源：评论

学校读者我要写书评

暂无评论

Acquisition method for effective electromagnetic parameters of honeycomb structures based on FNN-INN

引用

Journal of Applied Physics 2025年第17期137卷

作者： Zhang, Fan Chen, Xin Huang, Xiangguo Pan, Jingwei Yu, Dingfeng He, Bokun Wang, Juan Wu, Minghu Zhou, Tong Zhang, Yunhua Hubei Key Laboratory for High-efficiency Utilization of Solar Energy and Operation Control of Energy Storage System Hubei University of Technology Wuhan430068 China Hubei Engineering Research Center for Safety Monitoring of New Energy and Power Grid Equipment Hubei University of Technology Wuhan430068 China Hubei Key Laboratory of Marine Electromagnetic Detection and Control Wuhan430064 China Wuhan Second Ship Design and Research Institute Wuhan430064 China School of Electronic Information Wuhan University Wuhan430072 China

The effective electromagnetic parameters of honeycomb composite structures are crucial for studying their electromagnetic properties. However, most existing homogenization methods are based on static or quasi-static equivalence, considering only the effects of the electromagnetic parameters and the volume fraction of each phase medium on the effective electromagnetic parameters, while neglecting the influence of honeycomb aperture parameters. To address this, this paper proposes a novel homogenization method systematically analyzing the influence of honeycomb structure parameters, particularly aperture parameters, on the effective electromagnetic parameters. This method enables the direct acquisition of the effective electromagnetic parameters of honeycomb structures from their geometric parameters and the material parameters of each phase medium. First, this paper uses the geometric parameters of the honeycomb structure and the material parameters of each phase medium as inputs to construct a forward neural network for predicting the reflection coefficient (S11 parameter). Subsequently, the S11 parameter matrix is rapidly constructed using the reflectance formula. Correlation analysis and global feature extraction in two-dimensional space yield the feature vector matrix, representing the transformed S11 parameters. These are used as inputs to construct an inverse neural network to predict the effective electromagnetic parameters of the honeycomb structure. Finally, this paper reconstructs reflectance curves for two-layer and three-layer honeycomb structures, with mean absolute error below 0.26, validating the proposed method's effectiveness and accuracy. © 2025 Author(s).

关键词： Homogenization method

来源：评论

学校读者我要写书评

暂无评论

Low-Carbon Dispatching for Virtual power Plant with Aggregated Distributed Energy Storage Considering Spatiotemporal Distribution of Cleanness Value

引用

Journal of Modern power systems and Clean Energy 2024年第2期12卷 346-358页

作者： Hongchao Gao Tai Jin Guanxiong Wang Qixin Chen Chongqing Kang Jingkai Zhu State Key Laboratory of Power System Operation and Control Department of Electrical EngineeringTsinghua UniversityBeijing 100084China Sichuan Energy Internet Research Institute Tsinghua University Chengdu 200016China Power Dispatching and Control Center of Shanghai Municipal Electric Power Company Shanghai 200122China IEEE

The scale of distributed energy resources is increasing,but imperfect business models and value transmission mechanisms lead to low utilization ratio and poor *** address this issue,the concept of cleanness value of distributed energy storage(DES)is proposed,and the spatiotemporal distribution mechanism is discussed from the perspectives of electrical energy and *** on this,an evaluation system for the environmental benefits of DES is constructed to balance the interests between the aggregator and the power system ***,an optimal low-carbon dispatching for a virtual power plant(VPP)with aggregated DES is constructed,where-in energy value and cleanness value are both *** achieve the goal,a green attribute labeling method is used to establish a correlation constraint between the nodal carbon potential of the distribution network(DN)and DES behavior,but as a cost,it brings multiple nonlinear ***,a solution method based on the convex envelope(CE)linear re-construction method is proposed for the multivariate nonlinear programming problem,thereby improving solution efficiency and ***,the simulation verification based on the IEEE 33-bus DN is *** simulation results show that the multidimensional value recognition of DES motivates the willingness of resource users to ***,resolving the impact of DES on the nodal carbon potential can effectively alleviate overcompensation of the cleanness value.

关键词： Distributed energy storage virtual power plant(VPP) spatiotemporal distribution low-carbon dispatching

来源：评论

学校读者我要写书评

暂无评论

Tailoring intermetallics via cellular boundary enables strong yet ductile property: An example in Gd-enriched neutron shielding alloys

引用

Scripta Materialia 2025年 265卷

作者： Hou, Kunlei He, Suyun Wei, Boxin Cui, Luqing Zang, Yihu Zhao, Peng Liang, Tian Ma, Guangcai Ma, Yingche Institute of Metal Research Chinese Academy of Sciences Shenyang110016 China CAS Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal Research Chinese Academy of Sciences Shenyang110016 China Tianjin Key Laboratory of Materials Laminating Fabrication and Interface Control Technology School of Materials Science and Engineering Hebei University of Technology Tianjin300401 China National Key Lab of Aerospace Power System and Plasma Technology Xi'an Jiaotong University Xi'an710049 China School of Mechanical Engineering Xi'an Jiaotong University Xi'an710049 China Department of Physics and Astronomy University of California Irvine IrvineCA92697 United States

Gd is a highly effective element for neutron shielding, but its minimal solubility promotes Gd-rich intermetallics that degrade alloy properties if not properly controlled. This study introduces an innovative approach to refine these intermetallics to a sub-micron scale and achieve a uniform distribution by leveraging the cellular boundaries formed during laser powder bed fusion. These cellular boundaries, combined with the tailored intermetallics, act as "modulators" that effectively impede plastic deformation while permitting dislocation motion, resulting in a satisfying strength-ductility synergy. The findings offer a promising direction for incorporating elements with low solubility but functional properties by tailoring intermetallics through cellular boundary engineering. © 2025 The Author(s)

关键词： Intermetallics

来源：评论

学校读者我要写书评

暂无评论

Research on two-dimensional fluid vibration axial transmission path model of axial piston pump

引用

High Technology Letters 2019年第1期25卷 48-56页

作者： Quan Lingxiao Bai Ruxia Zhang Qiwei Liu Song Lu Yueliang College of Mechanical Engineering Yanshan University Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control Nanjing Engineering Institute of Aircraft System Jincheng AVIC

High speed and high pressure can enhance the vibration of axial piston pump. A fluid vibration transmission law of axial piston pump is studied in this paper. According to harmonic response analysis results, a transmission path analysis is used to establish a two-dimensional fluid vibration transmission path model in the vertical plane, which has characteristics of multi excitation sources, multi-path and multi-receptors. Model parameters are obtained by experimental and numerical analysis. Matlab is used to solve the model, and acceleration vibration response of three shells is got. To reduce the effect of mechanical vibration, the surface acceleration of pump is tested under low speed condition. Results show that the model can accurately reveal transmission law of fluid vibration and the accuracy is more than 90%. The research lays a foundation for exploring vibration transmission law and vibration control.

关键词： axial piston pump fluid vibration vibration transmission path vibration response

来源：评论

学校读者我要写书评

暂无评论

Angle Tracking control Strategy for Steering-by-Wire system with Dual Steering Actuator Motors 41

Angle Tracking Control Strategy for Steering-by-Wire System ...

引用

第41届中国控制会议

作者： Xuhang Zhang Linhui Zhao Guohuang Ji Zhiyuan Liu Department of Control Science and Engineering Harbin Institute of Technology Intelligent Power System Co. Ltd.

ISBN: (数字)9789887581536

ISBN: (纸本)9781665482561

Steering-by-wire(SBW) is a key technology to realize angle tracking for autonomous vehicles,and it directly affects the performance of active *** reliability performance of SBW system can be greatly improved by adopting dual motor steering ***,the dual-motor SBW vehicle often loses its stability due to the external interference,and the asynchronous response between the dual steering actuator motors will further deteriorate the stability of the *** purpose of this paper is to establish a method of angle tracking for the dual-motor steering by wire ***,the model of SB W was established and its validity was proofed by comparing the steering performance between the SBW and the traditional mechanical steering ***,by considering parameters uncertainties and difference of wheel load torque of the dual steering actuator motors,the steering angle tracking control strategy of dual motor SBW was *** paper established methods for the synchronization control of dual motor and closed-loop control of angle *** the angle synchronization error was decreased by current compensation *** validation results show that the proposed control strategy can decrease the synchronization error of dual motor and ensure the reliability of angle tracking.

关键词： Steering-by-wire Dual-motor Angle tracking Synchronization control

来源：评论

学校读者我要写书评

暂无评论

Acquisition and management of condition information of equipments based on wireless sensor networks

引用

Journal of Computational Information systems 2011年第7期7卷 2420-2426页

作者： He, Qing Du, Kebing Zhao, Xiaotong Du, Dongmei Key Laboratory of Condition Monitoring and Control for Power Plant School of Energy Power and Mechanical Engineering North China Electric Power University Beijing 102206 China Division of Power System China Electric Power Research Institute Beijing 100192 China

To improve performance information acquirement and management of traditional monitoring system and realize wireless health monitoring for widely dispersed or product-line equipments, a novel wireless vibration monitoring system with a wireless microcontroller based on wireless sensors networks has been developed. The configuration of system as well as the hardware of wireless monitoring node is presented. The method of building wireless network, the communication protocol of system as well as the monitoring program of node are discussed. It is proved by the experiments that the system is stable in operation and reliable in transmission. Therefore, the system is suitable for data collection and environmental monitoring of industrial equipments in field. Copyright © 2011 Binary Information Press.

关键词： Information management

来源：评论

学校读者我要写书评

暂无评论

An optimized time-adaptive aerothermal coupling calculation method for aerothermal analysis of disc cavity system

引用

Chinese Journal of Aeronautics 2024年第9期37卷 164-177页

作者： Shuai BI Junkui MAO Lei WANG Feng HAN College of Energy and Power Engineering Nanjing University of Aeronautics and AstronauticsNanjing 20016China AECC Aeroengine Control System Institute Wuxi 214063China Integrated Energy Institute Nanjing University of Aeronautics and AstronauticsNanjing 210016China

In order to further achieve the balance between the calculation accuracy and efficiency of the transient analysis of the aero-engine disc cavity system,an Optimized Time-adaptive Aerother-mal Coupling calculation(OTAC)method has been *** combines one-dimensional tran-sient calculation of air system,Conventional Sequence Staggered(CSS)method,Time-adaptive Aerothermal Coupling calculation(TAC)method and differential evolution optimization algorithm to obtain an efficient and high-precision aerothermal coupling calculation method of air *** both the heat conduction in the solid domain and the flow in the fluid domain as unsteady states in the OTAC,the interaction of fluid-solid information within a single coupling time step size was implemented based on the CSS ***,the coupling time step size was automatically adjusted with the number of iterations by using the Proportional-Integral-Deri vative(PID)*** show that when compared with the traditional loosely coupling method with a fixed time step size,the computational accuracy and efficiency of the OTAC method are improved by 8.9%and 30%,*** with the tight coupling calculation,the OTAC method can achieve a speedup of 1 to 2 orders of magnitude,while the calculation error is maintained within 6.1%.

关键词： Air system 1D-3D coupling Conjugate heat transfer Transient calculation Adaptive time step size

来源：评论

学校读者我要写书评

暂无评论

Infrared and Visible Image Fusion Based on Res2Net-Transformer Automatic Encoding and Decoding

引用

Computers, Materials & Continua 2024年第4期79卷 1441-1461页

作者： Chunming Wu Wukai Liu Xin Ma Key Laboratory of Modern Power System Simulation and Control&Renewable Energy Technology School of Electrical EngineeringNortheast Electric Power UniversityJilin132012China School of Electrical Engineering Northeast Electric Power UniversityJilin132012China School of Aeronautical Engineering Jilin Institute of Chemical TechnologyJilin132022China

A novel image fusion network framework with an autonomous encoder and decoder is suggested to increase thevisual impression of fused images by improving the quality of infrared and visible light picture fusion. The networkcomprises an encoder module, fusion layer, decoder module, and edge improvementmodule. The encoder moduleutilizes an enhanced Inception module for shallow feature extraction, then combines Res2Net and Transformerto achieve deep-level co-extraction of local and global features from the original picture. An edge enhancementmodule (EEM) is created to extract significant edge features. A modal maximum difference fusion strategy isintroduced to enhance the adaptive representation of information in various regions of the source image, therebyenhancing the contrast of the fused image. The encoder and the EEM module extract features, which are thencombined in the fusion layer to create a fused picture using the decoder. Three datasets were chosen to test thealgorithmproposed in this paper. The results of the experiments demonstrate that the network effectively preservesbackground and detail information in both infrared and visible images, yielding superior outcomes in subjectiveand objective evaluations.

关键词： Image fusion Res2Net-Transformer infrared image visible image

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：