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2019 International Congress on Ultrasonics, ICU 2019

作者： Dong, Huijuan Wang, Yi Guan, Yingzi Mu, Guanyu Zhao, Jie State Key Laboratory of Robotics and System Harbin Institude of Technology Heilongjiang Harbin150001 China

ISBN: (纸本)9781665407090

Standing wave acoustic levitation and transmission technique has been widely used in many research areas. However, the vibration of particles in an acoustic field restricts their applications. In this work, a kind of mechanism is developed by the authors, in which not only a harmonic linear actuator but also position feedback are used to precisely adjust the distance between the radiator and the reflector with micrometric accuracy. And video computing software is applied to track the motion of the particle. The influence of the factors on the frequencies of the particle both in vertical and horizontal were detailed. Besides, the acceleration field was calculated, which is in good agreement with the model of spring oscillator of an acoustic field. © 2020 Acoustical Society of America.

关键词： Acoustic fields

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Joint Observations of Plasmapause Surface Waves and Giant Undulations in the Electron Aurora

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Journal of Geophysical Research: Space Physics 2025年第6期130卷

作者： Xin-Yu Ai Jie Ren Qiu-Gang Zong Yi-Xin Hao Zi-Jian Feng Ting-Yan Xiang Institute of Space Physics and Applied Technology Peking University Beijing China Key Laboratory of Intraplate Volcanoes and Earthquakes China University of Geosciences (Beijing) Beijing China State Key Laboratory of Lunar and Planetary Science Macau University of Science and Technology Macau China Max Planck Institute for Solar System Research Göttingen Germany

After the onset of an intense storm-time substorm (the minimum AL ∼ ${\sim} $ −2,400 nT) on 8 September 2017, both Van Allen Probes and ground stations observed large-amplitude plasmasphere surface waves (PSWs) in the duskside, which lasted for more than 3 hr. Van Allen Probe B observations show that PSWs caused spatial and temporal modulations of sub-keV electrons with bidirectional pitch-angle distributions and higher-frequency plasma waves outside the plasmapause at the L-shells of 3.5–5.5. These kinetic-scale waves include kinetic Alfvén waves (KAWs) with frequencies below 10 Hz, time domain structures with frequencies from tens to hundreds of Hz, and electrostatic electron cyclotron harmonic waves (ECHs) with frequencies of tens of kHz. The bidirectional pitch angles and flux enhancement of sub-keV electrons indicate that they originate from the ionospheric outflow and are susceptible to pitch-angle scattering by kinetic-scale plasma waves. Following Probe B with a time delay of about 2 hr, Probe A observed PSW-associated ULF waves inside the plasmasphere at L-shells of 5–6, which can cause the drift-bounce resonance of cold ( < ${< } $ 50 eV) electrons. Corresponding to the duration and location of PSWs, DMSP-F17 observed intense sub-keV electron precipitation and weak ion precipitation, which coincides with the observations of giant undulations (GUs) in the electron aurora. These space-ground joint observations provide new sights into understanding the complicated middle processes between magnetospheric PSWs and ionospheric GUs. Sub-keV ionospheric outflows (both electrons and protons) and different kinetic-scale waves outside the plasmapause were modulated by plasmasphere surface waves (PSWs) ULF waves, decayed PSWs away from the plasmapause, only affected the low-energy electrons ( < ${< } $ 50 eV) in the plasmasphere Giant undulations in the electron aurora observed by Defense Meteorological Satellite Program are closely associated with sub-keV electrons a

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BugListener: Identifying and Synthesizing Bug Reports from Collaborative Live Chats

arXiv

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arXiv 2022年

作者： Shi, Lin Mu, Fangwen Zhang, Yumin Yang, Ye Chen, Junjie Chen, Xiao Jiang, Hanzhi Jiang, Ziyou Wang, Qing Laboratory for Internet Software Technologies Institute of Software Chinese Academy of Sciences Beijing China University of Chinese Academy of Sciences Beijing China State Key Laboratory of Computer Science Institute of Software Chinese Academy of Sciences Beijing China Science & Technology on Integrated Information System Laboratory Institute of Software Chinese Academy of Sciences Beijing China School of Systems and Enterprises Stevens Institute of Technology HobokenNJ United States Tianjin University College of Intelligence and Computing Tianjin China

In community-based software development, developers frequently rely on live-chatting to discuss emergent bugs/errors they encounter in daily development tasks. However, it remains a challenging task to accurately record such knowledge due to the noisy nature of interleaved dialogs in live chat data. In this paper, we first formulate the task of identifying and synthesizing bug reports from community live chats, and propose a novel approach, named BugListener, to address the challenges. Specifically, BugListener automates three sub-tasks: 1) Disentangle the dialogs from massive chat logs by using a Feed-Forward neural network;2) Identify the bug-report dialogs from separated dialogs by leveraging the Graph neural network to learn the contextual information;3) Synthesize the bug reports by utilizing Transfer Learning techniques to classify the sentences into: observed behaviors (OB), expected behaviors (EB), and steps to reproduce the bug (SR). BugListener is evaluated on six open source projects. The results show that: for bug report identification, BugListener achieves the average F1 of 77.74%, improving the best baseline by 12.96%;and for bug report synthesis task, BugListener could classify the OB, EB, and SR sentences with the F1 of 84.62%, 71.46%, and 73.13%, improving the best baselines by 9.32%, 12.21%, 10.91%, respectively. A human evaluation study also confirms the effectiveness of BugListener in generating relevant and accurate bug reports. These demonstrate the significant potential of applying BugListener in community-based software development, for promoting bug discovery and quality improvement. Copyright © 2022, The Authors. All rights reserved.

关键词： Software design

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Practical fractional-order variable-gain super-twisting control with application to wafer stages of photolithography systems

arXiv

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arXiv 2021年

作者： Kuang, Zhian Sun, Liting Gao, Huijun Tomizuka, Masayoshi Research Institute of Intelligent Control and Systems Harbin Institute of Technology Harbin150001 China State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin150001 China Mechanical Control System Lab Mechanical Engineering Department University of California BerkeleyCA94720 United States

In this paper, a practical fractional-order variable-gain super-twisting algorithm (PFVSTA) is proposed to improve the tracking performance of wafer stages for semiconductor manufacturing. Based on the sliding mode control (SMC), the proposed PFVSTA enhances the tracking performance from three aspects: 1) alleviating the chattering phenomenon via super-twisting algorithm and a novel fractional-order sliding surface (FSS) design, 2) improving the dynamics of states on the sliding surface with fast response and small overshoots via the designed novel FSS and 3) compensating for disturbances via variable-gain control law. Based on practical conditions, this paper analyzes the stability of the controller and illustrates the theoretical principle to compensate for the uncertainties caused by accelerations. Moreover, numerical simulations prove the effectiveness of the proposed sliding surface and control scheme, and they are in agreement with the theoretical analysis. Finally, practice-based comparative experiments are conducted. The results show that the proposed PFVSTA can achieve much better tracking performance than the conventional methods from various perspectives. Copyright © 2021, The Authors. All rights reserved.

关键词： Sliding mode control

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Wetland classification based on depth-adaptive convolutional neural networks using leaf-off SAR imagery

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Science of the Total Environment 2024年 957卷 177768页

作者： Zhang, Xin Du, Ling Tan, Shen McCarty, Gregory W. Zou, Zhenhua Department of Computing and Mathematics Manchester Metropolitan University ManchesterM1 5GD United Kingdom Department of Environmental Science & Technology University of Maryland College ParkMD20742 United States Hydrology and Remote Sensing Laboratory USDA-ARS BeltsvilleMD20705 United States State Key Laboratory of Efficient Production of Forest Resources Beijing Forestry University Beijing100083 China Sino-French Institute for Earth System Science College of Urban and Environmental Sciences Peking University Beijing100871 China Department of Geographical Sciences University of Maryland College ParkMD20742 United States

The recent development of deep learning (DL) techniques has created opportunities for classifying wetlands from remote sensing data (mainly optical data). However, the methods for accurately and efficiently classifying large-scale wetlands using DL and radar data that can be more effective than optical data still needs evaluation. In this study, we developed an end-to-end depth-adaptive convolutional neural network (CNN) for mapping wetlands using leaf-off time-series Sentinel-1 Synthetic Aperture Radar (SAR) imagery along with ancillary data. We examined the inclusion of multi-land cover proximity information and a CNN-based self-supervised SAR denoising procedure for enhancing wetland classification accuracy. The depth-adaptive CNN based on U-Net architecture was designed to classify wetland classes (emergent wetland, scrub-shrub wetland, forested wetland, and open water) in Delaware, U.S. while achieving optimization between model complexity (network depths) and accuracy. Results show that our proposed DL method (OA = 0.93, MIoU = 0.60) not only produced a higher classification accuracy than the traditional RF method (OA = 0.89, MIoU = 0.18) but also had a significantly reduced computational cost compared to established state-of-the-art CNNs (e.g., DeepLabV3+ and DANet) without loss of accuracy. The inclusion of multi-land cover proximity information (especially distances to forest and water) and the CNN-based self-supervised SAR denoising procedure can both enhance wetland classification accuracy, especially for forested wetland using traditional RF methods. These results demonstrated the novelty and efficiency of our proposed DL method for classifying wetlands by combing denoised SAR imagery and ancillary information, which provides insights on integration of DL approach and radar data for supporting operational wetland mapping at large spatial scales. © 2024 Elsevier B.V.

关键词： Self-supervised learning

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Effect of inverted T arrangement on AC pollution flashover characteristics of insulator strings

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High Voltage 2019年第2期4卷 97-104页

作者： Xingliang Jiang Xiaodong Ren Han Wang Xingbo Han Conglai Bi Zhiyu Li Ledong Hou State Key Laboratory of Power Transmission Equipment and System Security and New Technology College of Electrical EngineeringChongqing UniversityShapingba DistrictChongqing400044People's Republic of China

The arrangement of insulator strings has an effect on its pollution flashover characteristics.A new arrangement of insulator strings,inverted T-type arrangement,is proposed in this *** electric field distribution is simulated and the pollution flashover characteristics are tested in an artificial climate *** test results indicate that the inverted T-type arrangement can greatly improve the flashover voltage of polluted insulator strings,the‘7+2’inverted T-type arrangement can increase the flashover voltage of each insulator by 8.5%on average,and the‘3+3’inverted T-type arrangement can increase the flashover voltage of each insulator by 13.4%.The discharge process is different from that of the normal suspension string when the insulator string is inverted T-shaped,i.e.a local arc is produced at the low voltage end of the insulator string and develops downward along the suspension *** as for the horizontal tension string parts,it is difficult to generate arc during discharge development.

关键词： arrangement string pollution

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A compact control system and a myoelectric control method for multi-DOFs prosthetic hand

A compact control system and a myoelectric control method fo...

引用

2019 IEEE International Conference on Real-Time Computing and robotics, RCAR 2019

作者： Yang, Bin Jiang, Li Hu, Jianhao Li, Chongyang Liu, Hong State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin Heilong Jiang China

ISBN: (纸本)9781728137261

This paper introduces a compact control system for multi-DOFs prosthetic hand. Based on the optimization of sensors configuration and hardware structure of the control system, the power consumption and volume can meet the needs of the actual using. In addition, a myoelectric control method based on the principle of finite state machine (FSM) is integrated in the control system. The proposed method enables amputees to select one of the given gestures directly, and grasp objects. As the control method requires less electromyography electrodes comparing to the traditional myoelectric control method based on EMG pattern recognition, it's available for a wider range of amputees with less active muscles. To assess the performance of the proposed method, the experiments of grasping random objects by non-amputee subjects has been conducted with the 6-DOFs HIT-V prosthetic hand, and an amputee volunteer used this prosthetic hand for one day to demonstrate viability. The non-amputee experimental results indicate that subjects can select gesture correctly among seven gestures and accomplish the designed grasping tasks with a success rate up to 96.67% within a shorter time just using two electrodes, and amputee proved viability of proposed method in daily life. © 2019 IEEE.

关键词： Electrodes

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A novel inventory decoupling control strategy for sCO 2 cycle based on the net power superposition principle

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International Journal of Heat and Fluid Flow 2025年 116卷

作者： Cheng Chang Enhui Sun Jinliang Xu Xiaoming Zhang Huan Ye Qichen Qian Key Laboratory of Power Station Energy Transfer Conversion and System North China Electric Power University Ministry of Education Beijing 102206 China State Key Laboratory of Low-carbon Thermal Power Generation Technology and Equipments Harbin Boiler Company Limited Harbin 150046 China

The supercritical carbon dioxide (sCO 2 ) Brayton cycle has garnered considerable attention due to its exceptional efficiency and compact design. However, owing to grid load requirements, the sCO 2 cycle often operates at part-load, necessitating an investigation into its performance under such conditions. This paper employs the net power superposition principle and mathematical derivations based on the recompression cycle to address this need. Introducing a novel strategy, termed the inventory decoupling control strategy, enhances cycle thermal efficiency at part-load. By splitting the recompression cycle into two simple Brayton cycles and implementing independent inventory control strategies during load adjustment, thermal efficiency at part-load is significantly improved. A 20 MW sCO 2 cycle model incorporating this innovative part-load control strategy was developed for this study. Calculations demonstrate that the inventory decoupling control strategy offers notable efficiency advantages, with a thermal efficiency difference of up to 1.21 % at 30 % load. The primary rationale behind this novel control strategy is to redistribute the regenerative process, thereby enhancing net power superposition and reducing heat dissipation from the cooler during part-load operation. Additionally, the novel control strategy results in less variation in compressor efficiency, leading to higher overall compressor efficiency and enhanced safety. This approach further extends the applicability of the net power superposition principle and explores the potential of inventory control strategies, offering a new perspective for investigating control strategies of sCO 2 cycles under part-load conditions.

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Optical properties and potential of LB4 for THz wave generation 4

Optical properties and potential of LB4 for THz wave generat...

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4th International Symposium on High Power Laser Science and Engineering, HPLSE 2021

作者： Huang, Jingguo Li, Yang Huang, Zhiming Gao, Yanqing Ezhov, Dmitry Lubenko, Dmitry Andreev, Yury State Key Laboratory of Infrared Physics Shanghai Institute of Technical Physics 500 Yu Tian Road Shanghai200083 China Key Laboratory of Space Active Opto-Electronics Technology Shanghai Institute of Technical Physics 500 Yu Tian Road Shanghai200083 China Tomsk State University 36 Lenin Ave. Tomsk634050 Russia Institute of High Current Electronics SB RAS 2/3 Akademichesky Ave. Tomsk634055 Russia Institute of Monitoring of Climatic and Ecological System SB RAS 10/3 Akademichesky Ave. Tomsk634055 Russia

ISBN: (数字)9781510645431

ISBN: (纸本)9781510645424

Optical properties of a Li2B4O7 (LB4) crystal are determined in the spectral range 0.2-1.6 THz. Dispersion of the refractive index components for o- and e-wave are approximated in the form of Sellmeier equations. They are subsequently used to determine the possible interaction types and to calculate the phase-matching angles to get THz waves by difference frequency generation. The damage threshold is determined as well as the coherence length for all possible types of three wave interactions under the pump by fs Ti: Sapphire laser pulses at 950 nm. The efficiency of the processes is estimated. Using trains of hundreds of pulses at 950 nm it was found to be 1.32 times of that for β-BBO crystal laser pump. © 2021 SPIE.

关键词： Phase matching

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Riboflavin-modified lipo-polyplexes co-delivering CXCR4 siRNA and doxorubicin for treatment of highly metastatic cancer

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Journal of Chinese Pharmaceutical Sciences 2021年第3期30卷 189-205页

作者： Kaisen Li Rudong Wang Yiwei Peng Dawen Dong Xianrong Qi Department of Pharmaceutics School of Pharmaceutical SciencesPeking University Health Science CenterBeijing 100191China Beijing Key Laboratory of Molecular Pharmaceutics and New Drug Delivery System School of Pharmaceutical SciencesPeking UniversityBeijing 100191China State Key Laboratory of Advanced Pharmaceutical Formulation with High Technology Yangtze River Pharmaceutical GroupJiangsu 225300China

SDF-1/CXCR4 has been recognized as one of the most relevant chemokine signaling pathways to cancer metastasis,and siRNA targeting CXCR4 may provide potential improvements to treat those highly metastatic cancers,especially when combined with *** the present study,we constructed riboflavin-modified lipo-polyplexes to co-deliver CXCR4 siRNA and doxorubicin for cancer *** was covalently conjugated to polyethyleneimine(PEI)with acid-cleavable hydrazine bond,and the obtained acid-sensitive conjugate was efficiently condensed with siRNA to form polyplexes,which were further coated with riboflavin-tailed lipid-membrane to prepare the lipo-polyplexes *** the fact that tumor cells overexpress riboflavin receptors,the riboflavin modification effectively enhanced uptake of lipo-polyplexes by tumor cells in a receptor-mediated *** riboflavin-modified lipo-polyplexes co-delivering CXCR4 siRNA and doxorubicin effectively decreased viability and invasiveness of tumor cells in vitro,and inhibited primary tumor growth and tumor metastasis in vivo.

关键词： Riboflavin Lipo-polyplexes Co-delivery SiRNA Doxorubicin

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