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Prescribed fast tracking control for flexible air-breathing hypersonic vehicles:An event-triggered case

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Chinese Journal of Aeronautics 2021年第11期34卷 200-215页

作者： Xingling shao Yi SHI Wendong ZHANG jiang ZHAO The Key Laboratory of Instrumentation Science&Dynamic Measurement Ministry of EducationNorth University of ChinaTaiyuan 030051China School of Instrument and Electronics North University of ChinaTaiyuan 030051China School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China

In this paper,a prescribed fast tracking control scheme is proposed for Flexible Airbreathing Hypersonic Vehicles(FAHV)subject to lumped disturbances and limited *** maintain tracking errors of velocity and altitude converge to a predefined region with a prescribed time and release the transient intense fluctuations encountered in classical Prescribed Performance Control(PPC)using a fast decaying rate,a tracking differentiator-based PPC is presented,where the reaching time and the maximum time differentiation of preselected envelopes can be regulated as a prior via fixing an acceleration factor,so that a guaranteed fast convergence speed can be realized with reduced ***,to avoid the excessive occupation of limited resources(energy and communication)and guarantee a remarkable tracking accuracy,switching event-triggered mechanisms are constructed for FAHV control realization,which provide a promising way to pursue a desired level of tracking performance with a low energy ***,Uncertainty and Disturbance Estimators(UDE)and Sigmoid function-based Tracking Differentiators(STD)are employed to provide disturbance estimation and reference derivation with a low computational ***,robust control laws are designed to compensate for the sampling error induced by event-triggered conditions,meanwhile Zeno phenomena can be effectively *** simulation results and comparisons validate the effectiveness of the proposed scheme.

关键词： Flexible air-breathing hypersonic vehicle Prescribed performance control Switching event-triggered Tracking differentiator Uncertainty and disturbance estimator

Snapshot boosting: a fast ensemble framework for deep neural networks

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Science China(Information Sciences) 2020年第1期63卷 77-88页

作者： Wentao ZHANG Jiawei jiang Yingxia shao Bin CUI Center for Data Science Peking University National Engineering Laboratory for Big Data Analysis and Applications Department of Computer Science Beijing Key Lab of Intelligent Telecommunications Software and Multimedia School of Computer ScienceBeijing University of Posts and Telecommunications Key Lab of High Confidence Software Technologies Department of Computer SciencePeking University

Boosting has been proven to be effective in improving the generalization of machine learning models in many fields. It is capable of getting high-diversity base learners and getting an accurate ensemble model by combining a sufficient number of weak learners. However, it is rarely used in deep learning due to the high training budget of the neural network. Another method named snapshot ensemble can significantly reduce the training budget, but it is hard to balance the tradeoff between training costs and diversity. Inspired by the ideas of snapshot ensemble and boosting, we propose a method named snapshot boosting. A series of operations are performed to get many base models with high diversity and accuracy, such as the use of the validation set, the boosting-based training framework, and the effective ensemble strategy. Last, we evaluate our method on the computer vision(CV) and the natural language processing(NLP) tasks, and the results show that snapshot boosting can get a more balanced trade-off between training expenses and ensemble accuracy than other well-known ensemble methods.

关键词： ensemble learning deep learning boosting neural network snapshot ensemble

Five-axis flank milling tool path generation with curvature continuity and smooth cutting force for pockets

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Chinese Journal of Aeronautics 2020年第2期33卷 730-739页

作者： Changqing LIU Yingguang LI Xin jiang Wenyao shao College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

In order to ensure machining stability,curvature continuity and smooth cutting force are very important so as to meet the constraints of both cutting force and kinematics of machine *** five-axis flank milling,it is difficult to meet both of the constraints because tool path points and tool axis vectors interact with each *** this paper,multiple relationships between tool path points and tool axis vectors with cutting force and kinematics of machine tools are established,and the strategies of corner-looping milling and clothoidal spirals are combined so as to find feasible solutions under both of the *** path parameters are iterated by considering the maximum cutting force and the feasible range of the tool axis vector,and eventually a curvature continuity five-axis flank milling tool path with smooth cutting force is *** experimental results show that the conditions of cutting force are satisfied,vibration during the process of machining is reduced,and the machining quality of the surface is improved.

关键词： Curvature continuity Cutting force Five-axis flank milling Machining Tool path generation

Azopyridine-imidacloprid derivatives as photoresponsive neonicotinoids

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Chinese Chemical Letters 2016年第5期27卷 635-639页

作者： Shen Li Run-jiang song Dong-Hui Wang Xue Tian Xu-Sheng shao Zhong Li Shanghai Key Laboratory of Chemical Biology School of Pharmacy East China University of Science and Technology Shanghai 200237 China College of Life Science Perking University Beijing 100871 China

A series of imidacloprid derivatives containing an azopyridine motif as a photoswitchable functional group were designed and synthesized. The new version of photoresponsive imidacloprid analogues showed improved solubility in comparison with their azobenzene analogues. 1.2 to 2-fold activity difference was observed for these azopyridine-imidacloprids against house fly （Musca domestica） and cowpea aphid （Aphis craccivora） upon irradiation.

关键词： Azopyridine Photoresponsive Imidacloprid Solubility Insecticide

Identifying the limiting distribution by a general approach of Stein's method

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Science China Mathematics 2016年第12期59卷 2379-2392页

作者： shao Qi-Man ZHANG Zhuo-song Department of Statistics The Chinese University of Hong Kong

A general exchange pair approach is developed to identify the limiting distribution for any sequence of random variables, by calculating the conditional mean and the conditional second moments. The error of approximation is also studied. In particular, a Berry-Esseen type bound of O(n^(-3/4)) is obtained for the Curie-Weiss model at the critical temperature.

关键词： Stein's method exchangeable pair limiting distribution Berry-Esseen bounds Curie-Weiss model

Remeasurement of the Half-Life of ^(79)Se with the Projectile X-Ray Detection Method

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Chinese Physics Letters 2001年第6期18卷 746-749页

作者： jiang song-Sheng HE Ming DIAO Li-Jun GUO Jing-Ru WU shao-Yong China Institute of Atomic Energy P.O.Box 275(49)Beijing 102413

Remeasurement of the half-life of ^(79)Se has been carried out with the projectile x-ray detection(PXD)in accelerator mass *** made two major improvements over our earlier ^(79)Se half-life determination[*** B 123(1997)403].Fristly,the PXD technique has been used for separation of ^(79)Se and 75Se from 79Br and 75As isobars ***,the half-life of ^(79)Se has been measured relative to the known precise half-life of ^(75)Se(119.79±0.04d).A more reliable half-life of ^(79)Se measured with the PXD technique is(2.95±0.38)×10^(5)y,about a factor of one lower than the previous value,1.1 × 10^(6)*** problems in the previous measurement are discussed.

关键词： spectrometry precise separation

Optimizing partitioning strategies for faster inverted index compression

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Frontiers of Computer Science 2019年第2期13卷 343-356页

作者： Xingshen song Yuexiang YANG Yu jiang Kun jiang College of Computer National University of Defense Technology Changsha 410000 China School of Electronic and Information Engineering Xi'an Jiaotong University Xi'an 710000 China

The inverted index is a key component for search engines to manage billions of documents and quickly respond to users' queries. Whereas substantial effort has been devoted to reducing space occupancy and decoding speed, the encoding speed when constructing the index has been overlooked. Partitioning the index aligning to its clustered distribution can effectively minimize the compressed size while accelerating its construction procedure. In this study, we introduce compression speed as one criterion to evaluate compression techniques, and thoroughly analyze the performance of different partitioning strategies. Optimizations are also proposed to enhance state-of-the-art methods with faster compression speed and more flexibility to partition an index. Experiments show that our methods offer a much better compression speed, while retaining an excellent space occupancy and decompression speed, networks.

关键词： in verted index index compression optimal partition approximation algorithm

Effect of nano-carbon black content on wetting phenomenon of molten steel and alumina-carbon ceramic filter substrates

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Journal of Iron and Steel Research International 2024年第8期31卷 1900-1913页

作者： Jin-wen song Wen Yan Zhe Chen Ying Liu shao-song Hong The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina National-provincial Joint Engineering Research Center of High Temperature Materials and Lining Technology Wuhan University of Science and TechnologyWuhan 430081HubeiChina jiangsu Sheng Nai New Materials Co. Ltd.Taizhou 225503JiangsuChina

The effect of nano-carbon black content(O,8 and 12 wt.%)on the wettability of molten steel on Al_(2)O_(3)-C substrates was investigated by the sessile drop wetting method at 1500℃ under argon *** the beginning of the wetting experiment,the contact angle decreased with the increase in nano-carbon black *** the wetting experiment progressed,FeAl_(2)0_(4) layer and sheet Al_(2)O_(3) layer were found at the interface between the molten steel and the Al_(2)O_(3)-C substrates with O and 8 wt.% nano-carbon black content,and the contact angle deceased with *** the content of nano-carbon black was 12 wt.%,a large number of nano-Al_(2)O_(3) whiskers were observed,which made the contact angle between the molten steel and Al_(2)O_(3)-C substrate become *** on the scanning electron microscope and energy dispersive spectrometry results,the formation mechanism of FeAl2O4 layer and Al_(2)O_(3) layer and the interfacial reaction mechanism were proposed.

关键词： Contact angle Nano-carbon black Al_(2)O_(3)-C substrate Molten steel Interfacial reaction

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教育教学论坛 2020年第32期 226-228页

作者：黄肖霄赵鹏刘庆博姚国栋娄丽丽宋少江沈阳药科大学中药学院辽宁省基于计算化学的天然抗肿瘤药物研究与开发重点实验室辽宁沈阳110016

在中药学专业的人才培养中,对本科生进行科研实践能力的引导和培养不仅是社会的要求,而且也是确保创新人才培养质量的基本保障。根据近年来开展的引导与培养中药学相关专业本科生科研能力的实践经验,探讨与分析了现阶段中药相关专业开... 详细信息

在中药学专业的人才培养中,对本科生进行科研实践能力的引导和培养不仅是社会的要求,而且也是确保创新人才培养质量的基本保障。根据近年来开展的引导与培养中药学相关专业本科生科研能力的实践经验,探讨与分析了现阶段中药相关专业开展本科生科研的意义与作用,并针对如何做好引导本科生参与科研实践提出了一些看法,包括如何在本科生科研培养过程中树立端正的学风;将教学与科研相结合;建立本科生和研究生科研中的合作式学习模式;根据实际情况多形式、多层次地开展本科生科研活动,提高本科生的科研实践水平。

关键词：中药学科研实践创新思维