检索结果-南通市图书馆

Research on the navigation method of large-scale differential tail-control improvised guided munitions based on rotational speed constraints

在线全文

学校读者我要写书评

暂无评论

Defence technology（防务技术） 2024年第8期38卷 155-170页

作者： Ning Liu Wenjiang Zhao Yao Wang Kai Shen Zhong Su Wenhao Qi Yuedong Xie Beijing key laboratory of High Dynamic Navigation technology Beijing Information Science and Technology UniversityBeijing100192China Hua an Industry Group Co. Ltd.Qiqihar161006China Integrated Navigation and intelligent Navigation laboratory Beijing Institute of TechnologyBeijing100081China Beijing Institute of technology Beijing100081China

In the process of launching guided projectile under the conventional system, it is difficult to effectively obtain the precise navigation parameters of the projectile in the high dynamic environment. Aiming at this problem, this paper describes a new system of guided ammunition based on tail spin reduction. After analyzing the mechanism of the ammunition's tail spin reduction, a navigation method of large scale difference tail control simple guided ammunition based on speed constraint is proposed. In this method,the corresponding navigation constraints can be carried out by combining the rotation speed state of the ammunition itself, and the optimal solution of navigation parameters during the flight of the missile can be obtained by Extended Kalman Filter(EKF). Finally, the performance of the proposed method was verified by the simulation environment, and the hardware-in-the-loop simulation test and flight test were carried out to verify the performance of the method in the real environment. The experimental results show that the proposed method can achieve the optimal estimation of navigation parameters for simple guided ammunition with large-scale difference tail control. Under the conditions of simulation test and hardware-in-loop simulation test, the position and velocity errors calculated by the method in this paper converged. Under the condition of flight test, the spatial average error calculated by the method described in this paper is 6.17 m, and the spatial error of the final landing point is 3.50 *** this method, the accurate acquisition of navigation parameters in the process of projectile launching is effectively realized.

关键词： Guided projectiles Tail spin reduction RPM constraints Combined navigation Extended Kalman filter(EKF)

An electromagnetic semi-active dynamic vibration absorber for thin-walled workpiece vibration suppression in mirror milling

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2024年第8期45卷 1315-1334页

作者： Jianghua KONG Bei DING Wei WANG Zhixia WANG Juliang XIAO Hongyun QIU School of Mechanical Engineering Tianjin University Tianjin key laboratory of Nonlinear Dynamics and control key laboratory of Modern Mechanisms and Equipment Design of the state Ministry of Education Tianjin University

As critical components of aircraft skins and rocket fuel storage tank shells,large thin-walled workpieces are susceptible to vibration and deformation during machining due to their weak local stiffness. To address these challenges, we propose a novel tunable electromagnetic semi-active dynamic vibration absorber(ESADVA), which integrates with a magnetic suction follower to form a followed ESADVA(follow-ESADVA)for mirror milling. This system combines a tunable magnet oscillator with a follower,enabling real-time vibration absorption and condition feedback throughout the milling process. Additionally, the device supports self-sensing and frequency adjustment by providing feedback to a linear actuator, which alters the distance between magnets. This resolves the traditional issue of being unable to directly monitor vibration at the machining point due to space constraints and tool interference. The frequency shift characteristics and vibration absorption performance are comprehensively investigated. Theoretical and experimental results demonstrate that the prototyped follow-ESADVA achieves frequency synchronization with the milling tool, resulting in a vibration suppression rate of approximately 47.57%. Moreover, the roughness of the machined surface decreases by18.95%, significantly enhancing the surface quality. The results of this work pave the way for higher-quality machined surfaces and a more stable mirror milling process.

关键词： 70J35 mirror milling O326 self-sensing semi-active dynamic vibration absorber (SADVA) thin-walled workpiece vibration absorption tuning

An Improved Machine Learning Model for Pure Component Property Estimation

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Engineering 2024年第8期39卷 61-73页

作者： Xinyu Cao Ming Gong Anjan Tula Xi Chen Rafiqul Gani Venkat Venkatasubramanian state key laboratory of Industrial control technology College of Control Science and EngineeringZhejiang UniversityHangzhou 310027China Department of Physics Bard College at Simon’s RockGreat BarringtonMA 01230USA PSE for SPEED Company Charlottenlund DK-2920Denmark Sustainable Energy and Environment Thrust The Hong Kong University of Science and Technology(Guangzhou)Guangzhou 510000China Department of Applied Sustainability Széchenyi István UniversityGy}or 9026Hungary Complex Resilient intelligent Systems laboratory Department of Chemical EngineeringColumbia UniversityNew YorkNJ 10027USA

Information on the physicochemical properties of chemical species is an important prerequisite when performing tasks such as process design and product ***,the lack of extensive data and high experimental costs hinder the development of prediction techniques for these ***,accuracy and predictive capabilities still limit the scope and applicability of most property estimation *** paper proposes a new Gaussian process-based modeling framework that aims to manage a discrete and high-dimensional input space related to molecular structure representation with the group-contribution approach.A warping function is used to map discrete input into a continuous domain in order to adjust the correlation between different *** selection techniques,including prior elicitation and prior predictive checking,are also applied during the building procedure to provide the model with more information from previous research *** framework is assessed using datasets of varying sizes for 20 pure component *** 18 out of the 20 pure component properties,the new models are found to give improved accuracy and predictive power in comparison with other published models,with and without machine learning.

关键词： Group contribution Gaussian process Warping function Prior predictive checking

Time-synchronous-averaging-spectrum based on super-resolution analysis and application in bearing fault signal identification

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Zhejiang University-science A(Applied Physics & Engineering) 2024年第7期25卷 573-585页

作者： Zengle REN Yuan WANG Huiyue TANG Xin'an CHEN Wei FENG Guangdong Provincial key laboratory of Construction Robotics and intelligent Construction Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen518055China Shenzhen EBORAIL technology Co. Ltd.Shenzhen518038China National Supercomputing Center in Shenzhen Shenzhen518055China state key Lab of Rail Traffic control and Safety Beijing Jiaotong UniversityBeijing100044China University of Chinese Academy of sciences Beijing100190China Shenzhen University of Advanced technology Shenzhen518107China

Time-synchronous-averaging(TSA)is based on the idea of denoising by averaging,and it extracts the periodic components of a quasiperiodic signal and keeps the extracted waveform *** paper studies the mathematical properties of TSA,where three propositions are given to reveal the nature of *** paper also proposes a TSA-spectrum based on super-resolution analysis and it decomposes a signal without using any base *** contrast to discrete Fourier transform spectrum(DFT-spectrum),which is a spectrum in frequency domain,TSA-spectrum is a period-based spectrum,which can present more details of the cross effects between different periodic components of a quasiperiodic ***,a case study is carried out using bearing fault analysis to illustrate the performance of TSA-spectrum,where the rotation speed fluctuation of the shaft is estimated,which is about 0.12 ms *** extracted fault signals are presented and some insights are *** believe that this paper can provide new motivation for TSA-spectrum to be widely used in applications involving quasiperiodic signal processing(QSP).

关键词： Time-synchronous-averaging(TSA) Spectrum Quasiperiodic signal processing(QSP) Super-resolution analysis Bearingfaultdetection

An Encoding-Decoding Framework Based on CNN for circ RNA-RBP Binding Sites Prediction

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Electronics 2024年第1期33卷 256-263页

作者： Yajing GUO Xiujuan LEI Yi PAN School of Computer science Shaanxi Normal University Faculty of Computer science and control Engineering Shenzhen Institute of Advanced TechnologyChinese Academy of Sciences Department of Computer science Georgia State University

Predicting RNA binding protein(RBP) binding sites on circular RNAs(circ RNAs) is a fundamental step to understand their interaction mechanism. Numerous computational methods are developed to solve this problem, but they cannot fully learn the features. Therefore, we propose circ-CNNED, a convolutional neural network(CNN)-based encoding and decoding framework. We first adopt two encoding methods to obtain two original matrices. We preprocess them using CNN before fusion. To capture the feature dependencies, we utilize temporal convolutional network(TCN) and CNN to construct encoding and decoding blocks, respectively. Then we introduce global expectation pooling to learn latent information and enhance the robustness of circ-CNNED. We perform circ-CNNED across 37 datasets to evaluate its effect. The comparison and ablation experiments demonstrate that our method is superior. In addition, motif enrichment analysis on four datasets helps us to explore the reason for performance improvement of circ-CNNED.

关键词： Proteins RNA Neural networks Encoding Robustness Decoding Convolutional neural networks

同方期刊数据库

Mechanical properties of multi-scale germanium specimens from space solar cells under electron irradiation

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2024年第1期37卷 173-185页

作者： Jian QIU Maliya HEINI Jusha MA Wenjia HAN Xunchun WANG Jun YIN Yan SHI Cunfa GAO state key laboratory of Mechanics and control of Mechanical Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China School of Chemistry and Civil Engineering Shaoguan UniversityShaoguan 512005China key laboratory of Functional Materials and Devices for Special Environments of Chinese Academy of sciences Chinese Academy of SciencesUrumqi 830011China Shanghai Institute of space Power-Sources Shanghai 200245China

During long-term service in space,Gallium Arsenide(GaAs)solar cells are directly exposed to electron irradiation which usually causes a dramatic decrease in their *** the multilayer structure of solar cells,the germanium(Ge)layer occupies the majority of the thickness as the *** to the intrinsic brittleness of semiconductor material,there exist various defects during the preparation and assembly of solar cells,the influences of which tend to be intensified by the irradiation *** this work,first,Ge specimens for mechanical tests were prepared at scales from microscopic to ***,after different doses of electron irradiation,the mechanical properties of the Ge specimens were *** experimental results demonstrate that electron irradiation has an obvious effect on the mechanical property variation of Ge in diverse *** four-point bending test indicates that the elastic modulus,fracture strength,and maximum displacement of the Ge specimens all increase,and reach the maximum value at the irradiation dose of 1×10^(15)e/cm^(2).The micrometer scale cantilever and nanoindentation tests present similar trends for Ge specimens after *** Force Microscope(AFM)also observed the change in surface ***,a fitting model was established to characterize the relation between modulus change and electron irradiation dose.

关键词： Electron irradiation Germanium Mechanical properties Multi-scale space solar cells

Comprehensive study of the ultrafast photoexcited carrier dynamics in Sb_(2)Te_(3)–GeTe superlattices

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2024年第7期33卷 381-387页

作者：叶之江金钻明蒋叶昕卢琦贾梦辉钱冬黄夏敏李舟彭滟朱亦鸣 Terahertz technology Innovation Research Institute Terahertz Spectrum and Imaging Technology Cooperative Innovation CenterShanghai Key Laboratory of Modern Optical SystemUniversity of Shanghai for Science and TechnologyShanghai 200093China Shanghai Institute of intelligent science and technology Tongji UniversityShanghai 200092China key laboratory of Artificial Structures and Quantum control(Ministry of Education) Shenyang National Laboratory for Materials ScienceSchool of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China Tsung-Dao Lee Institute Shanghai Jiao Tong UniversityShanghai 200240China state key laboratory of Precision Spectroscopy East China Normal UniversityShanghai 200062China GBA Branch of Aerospace Information Research Institute Chinese Academy of SciencesGuangzhou 510700China Guangdong Provincial key laboratory of Terahertz Quantum Electromagnetics Guangzhou 510700China University of Chinese Academy of sciences Beijing 100039China

Chalcogenide superlattices Sb_(2)Te_(3)-GeTe is a candidate for interfacial phase-change memory(iPCM) data storage *** employing terahertz emission spectroscopy and the transient reflectance spectroscopy together,we investigate the ultrafast photoexcited carrier dynamics and current transients in Sb_(2)Te_(3)-GeTe *** orientation and excitation polarization dependences of the THz emission confirm that ultrafast thermo-electric,shift and injection currents contribute to the THz generation in Sb_(2)Te_(3)-GeTe *** decreasing the thickness and increasing the number of GeTe and Sb_(2)Te_(3) layer,the interlayer coupling can be enhanced,which significantly reduces the contribution from circular photo-galvanic effect(CPGE).A photo-induced bleaching in the transient reflectance spectroscopy probed in the range of~1100 nm to~1400 nm further demonstrates a gapped state resulting from the interlayer *** demonstrates play an important role in the development of iPCM-based high-speed optoelectronic devices.

关键词： Sb_(2)Te_(3)/GeTe superlattices ultrafast carrier dynamics interfacial phase change memory THz emission spectroscopy transient reflectance spectroscopy

Rapid prediction of flow and concentration fields in solid-liquid suspensions of slurry electrolysis tanks

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2024年第9期31卷 2006-2016页

作者： Tingting Lu Kang Li Hongliang Zhao Wei Wang Zhenhao Zhou Xiaoyi Cai Fengqin Liu state key laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China state key laboratory of intelligent Optimized Manufacturing in Mining&Metallurgy Process Beijing 102628China School of Materials science and Engineering Lanzhou University of TechnologyLanzhou 730050China School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China

Slurry electrolysis(SE),as a hydrometallurgical process,has the characteristic of a multitank series connection,which leads to various stirring conditions and a complex solid suspension *** computational fluid dynamics(CFD),which requires high computing resources,and a combination with machine learning was proposed to construct a rapid prediction model for the liquid flow and solid concentration fields in a SE *** scientific selection of calculation samples via orthogonal experiments,a comprehensive dataset covering a wide range of conditions was established while effectively reducing the number of simulations and providing reasonable weights for each ***,a prediction model of the SE tank was constructed using the K-nearest neighbor *** results show that with the increase in levels of orthogonal experiments,the prediction accuracy of the model improved *** model established with four factors and nine levels can accurately predict the flow and concentration fields,and the regression coefficients of average velocity and solid concentration were 0.926 and 0.937,*** with traditional CFD,the response time of field information prediction in this model was reduced from 75 h to 20 s,which solves the problem of serious lag in CFD applied alone to actual production and meets real-time production control requirements.

关键词： slurry electrolysis solid-liquid suspension computational fluid dynamics K-nearest neighbor algorithm rapid prediction

Anomaly-Resistant Decentralized state Estimation Under Minimum Error Entropy With Fiducial Points for Wide-Area Power Systems

在线全文

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2024年第1期11卷 74-87页

作者： Bogang Qu Zidong Wang Bo Shen Hongli Dong Hongjian Liu the College of Automation Engineering Shanghai University of Electric PowerShanghai 200090China IEEE the Department of Computer science Brunel University LondonUxbridgeMiddiesex UB83PHUK the College of Information science and technology Donghua UniversityShanghai 200051 the Engineering Research Center of Digitalized Textile and Fashion technology Ministry of EducationShanghai 201620China the Artificial Intelligence Energy Research Institute Northeast Petroleum UniversityDaqing 163318 the Heilongjiang Provincial key laboratory of Networking and intelligent control Northeast PetroleumDaqing 163318 the Sanya Offshore Oil&Gas Research Institute Northeast Petroleum UniversitySanya 572024China the key laboratory of Advanced Perception and intelligent control of High-End Equipment Ministry of EducationAnhui Polytechnic UniversityWuhu 2410000 the School of Mathematics and Physics Anhui Polytechnic UniversityWuhu 241000China

This paper investigates the anomaly-resistant decentralized state estimation(SE) problem for a class of wide-area power systems which are divided into several non-overlapping areas connected through transmission lines. Two classes of measurements(i.e., local measurements and edge measurements) are obtained, respectively, from the individual area and the transmission lines. A decentralized state estimator, whose performance is resistant against measurement with anomalies, is designed based on the minimum error entropy with fiducial points(MEEF) criterion. Specifically, 1) An augmented model, which incorporates the local prediction and local measurement, is developed by resorting to the unscented transformation approach and the statistical linearization approach;2) Using the augmented model, an MEEF-based cost function is designed that reflects the local prediction errors of the state and the measurement;and 3) The local estimate is first obtained by minimizing the MEEF-based cost function through a fixed-point iteration and then updated by using the edge measuring information. Finally, simulation experiments with three scenarios are carried out on the IEEE 14-bus system to illustrate the validity of the proposed anomaly-resistant decentralized SE scheme.

关键词： Decentralized state estimation(SE) measurements with anomalies minimum error entropy unscented Kalman filter wide-area power systems