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Stiffness of Postural Alignment System Based on 3-Axis Actuators for Large Aircraft Components

Chinese Journal of Mechanical Engineering 2010年第4期23卷 524-531页

作者： GUO Zhimin jiang Junxia KE Yinglin The State Key Lab of Fluid Power Transmission and Control Zhejiang University Hangzhou 310027 China

Aircraft digital flexible assembly fixture and technologies are widely used in developed countries, while the traditional jig-based assembly mode is still used in China. The application study of aircraft digital flexible assembly system is just beginning in our country recently. To meet the requirements of automated posture alignment and join in digital assembly system for large aircraft components, a novel fitting fixture called 3-axis actuator is developed. On the basis of the actuators, three kinds of posture alignment system for large aircraft components are proposed, including the non-redundant system, the redundant actuating system, and the redundant leg system, and their constitutions and properties are introduced. Through deriving the feeding transmission stiffness model of single actuator and analyzing the inverse kinematics of these systems, the relationship between the external force and the changes of position and orientation of large aircraft component is obtained, and then the postural alignment stiffness models are established. With the method mentioned above, the postural alignment stiffness of three systems is computed by using the algebraic formulate, and the results show that redundant properties can increase system＇s postural alignment stiffness. As an example, a optimized layout of the assembly system for a given model of aircraft is developed, the results of application show that the layout has many advantages, such as high accuracy, stiffness, stability, reliability, efficiency and flexible, which can satisfy the requirement of aircraft digital assembly system well. The proposed study of postural alignment stiffness for different systems can supply the theoretic support for the optimization layout design of aircraft digital assembly system, and contribute to evaluate the system working performance of systems.

关键词： 3-axis actuator large aircraft component redundant postural alignment stiffness posture-holding

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Flexible Power Supply System of AC Electric Arc Furnace

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Journal of Modern Power Systems and Clean Energy 2023年第2期11卷 622-633页

作者： Chongbin Zhao Qirong jiang Dong Liu Department of Electrical Engineering Tsinghua UniversityBeijing 100084China Capital Engineering&Research Incorporation Ltd. Beijing 100176China

The AC electric arc furnace(EAF)is becoming a core apparatus of the modern steel ***,it used to be a major threat of power quality in the traditional power supply *** this paper,a flexible power supply system of the AC EAF is proposed,which is expected to completely alter its inherent cognition of impact load in the power *** basics of the power supply for EAF are first reviewed and the novel techniques to enhance the operation flexibility of EAF are *** power circuit and the control structure are then presented,followed by the detailed strategies of various operations fully considering the features of EAF.A large disturbance stability criterion based on the mixed potential theory is also established for the practical *** electromagnetic transient simulations using PSCAD and benefit analyses verify the feasibility of the proposed system.

关键词： Electric arc furnace(EAF) power electronics control power quality power supply system stability analysis

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Comparison of performance between rescaled range analysis and rescaled variance analysis in detecting abrupt dynamic change

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Chinese Physics B 2015年第4期24卷 581-588页

作者：何文平刘群群姜允迪卢莹 National Climate Center China Meteorological Administration College of Mathematics and Statistics Nanjing University of Information Science and Technology Yangzhou Meteorological Office

In the present paper, a comparison of the performance between moving cutting data-rescaled range analysis （MC- R/S） and moving cutting data-rescaled variance analysis （MC-V/S） is made. The results clearly indicate that the operating efficiency of the MC-R/S algorithm is higher than that of the MC-V/S algorithm. In our numerical test, the computer time consumed by MC-V/S is approximately 25 times that by MC-R/S for an identical window size in artificial data. Except for the difference in operating efficiency, there are no significant differences in performance between MC-R/S and MC-V/S for the abrupt dynamic change detection. Mc-R/s and MC-V/S both display some degree of anti-noise ability. However, it is important to consider the influences of strong noise on the detection results of MC-R/S and MC-V/S in practical application

关键词： moving cutting data-rescaled range analysis moving cutting data-rescaled variance analysis abrupt dynamic change

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Facile Syntheses of (6S)-6-Fluoroshikimic Acid and (6R)-6-Hydroxyshikimic Acid

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Chemical Research in Chinese Universities 2002年第2期18卷 146-152页

作者： Chuanjun Song Shende jiang Gurdial Singh Department of Chemistry University of SunderlandSunderlandSR13SDUK Department of Applied Chemistry Tianjin UniversityTianjin 300072P.R.China

(6S)-6-Fluoroshikimic acid 2 and (6 R ) 6 hydroxyshikimic acid 3 have been synthesized via an OsO 4 catalysed dihydroxylation of diene 7, which was derived from (-) shikimic acid 1.

关键词： Shikimate pathway Shikimic acid Fluoroshikimic acid Dihydroxylation Fluorination

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Gas Film Disturbance Characteristics Analysis of High-Speed and High-Pressure Dry Gas Seal

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Chinese Journal of Mechanical Engineering 2016年第6期29卷 1226-1233页

作者： CHEN Yuan jiang Jinbo PENG Xudong Engineering Research Center of Process Equipment and lts Re-manufacturing of Ministry of Education Zhejiang University of Technology Hangzhou 310000 China

The dry gas seal（DGS） has been widely used in high parameters centrifugal compressor, but the intense vibrations of shafting, especially in high-speed condition, usually result in DGS＇s failure. So the DGS＇s ability of resisting outside interference has become a determining factor of the further development of centrifugal compressor. However, the systematic researches of which about gas film disturbance characteristics of high parameters DGS are very little. In order to study gas film disturbance characteristics of high-speed and high-pressure spiral groove dry gas seal（S-DGS） with a flexibly mounted stator, rotor axial runout and misalignment are taken into consideration, and the finite difference method and analytical method are used to analyze the influence of gas film thickness disturbance on sealing performance parameters, what＇s more, the effects of many key factors on gas film thickness disturbance are systematically investigated. The results show that, when sealed pressure is 10.1MPa and seal face average linear velocity is 107.3 m/s, gas film thickness disturbance has a significant effect on leakage rate, but has relatively litter effect on open force; Excessively large excitation amplitude or excessively high excitation frequency can lead to severe gas film thickness disturbance; And it is beneficial to assure a smaller gas film thickness disturbance when the stator material density is between 3.1 g/cm3 to 8.4 g/cm3; Ensuring sealing performance while minimizing support axial stiffness and support axial damping can help to improve dynamic tracking property of dry gas seal. The proposed research provides the instruction to optimize dynamic tracking property of the DGS.

关键词： high-speed and high-pressure dry gas seal gas film thickness disturbance dynamic tracking property

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First demonstration of a self-aligned p-channel GaN back gate injection transistor

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Journal of Semiconductors 2024年第11期45卷 69-73页

作者： Yingjie Wang Sen Huang Qimeng jiang Jiaolong Liu Xinhua Wang wen Liu Liu Wang Jingyuan Shi Jie Fan Xinguo Gao Haibo Yin Ke Wei Xinyu Liu High-Frequency High-Voltage Device and Integrated Circuits Research and Development Center Institute of Microelectronics of the Chinese Academy of SciencesBeijing 100029China School of Integrated Circuits University of Chinese Academy of SciencesBeijing 100049China China School of Advanced Technology Xi'an Jiaotong-Liverpool UniversitySuzhou 215123China

In this study,we present the development of self-aligned p-channel Ga N back gate injection transistors(SA-BGITs)that exhibit a high ON-state *** achievement is primarily attributed to the conductivity modulation effect of the 2-D electron gas(2DEG,the back gate)beneath the 2-D hole gas(2DHG)***-BGITs with a gate length of 1μm have achieved an impressive peak drain current(I_(D,MAX))of 9.9 m A/*** fabricated SA-BGITs also possess a threshold voltage of 0.15 V,an exceptionally minimal threshold hysteresis of 0.2 V,a high switching ratio of 10~7,and a reduced ON-resistance(RON)of 548Ω·***,the SA-BGITs exhibit a steep sub-threshold swing(SS)of 173 mV/dec,further highlighting their suitability for integration into Ga N logic circuits.

关键词： GaN p-FETs self-alignment back gate threshold hysteresis conductivity modulation

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3D analytical solution for a rotating transversely isotropic annular plate of functionally graded materials

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第7期8卷 1038-1043页

作者： CHEN jiang-ying CHEN Wei-qiu Faculty of Engineering Ningbo University Ningbo 315211 China Department of Civil Engineering Zhejiang University Hangzhou 310027 China

The analytical solution for an annular plate rotating at a constant angular velocity is derived by means of direct displacement method from the elasticity equations for axisymmetric problems of functionally graded transversely isotropic media. The displacement components are assumed as a linear combination of certain explicit functions of the radial coordinate, with seven undetermined coefficients being functions of the axial coordinate z. Seven equations governing these z-dependent functions are derived and solved by a progressive integrating scheme. The present solution can be degenerated into the solution of a rotating isotropic functionally graded annular plate. The solution also can be degenerated into that for transversely isotropic or isotropic homogeneous materials. Finally, a special case is considered and the effect of the material gradient index on the elastic field is illustrated numerically.

关键词： Functionally graded materials Transversely isotropic Rotating annular plate Analytical solution

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Stability analysis of switched positive nonlinear systems: an invariant ray approach

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Science China(Information Sciences) 2019年第11期62卷 174-188页

作者： Hao YANG Xudong ZHAO Bin jiang College of Automation Engineering Nanjing University of Aeronautics and Astronautics School of Control Science and Engineering Dalian University of Technology

This paper addresses the stability problem associated with a class of switched positive nonlinear systems in which each vector field is homogeneous, cooperative, and irreducible. Instead of using the Lyapunov function approach, we fully establish the invariant ray analysis method to establish several stability conditions that depend on the states, rays, and/or times. We illustrate the efficiency of our proposed approach using the example of a chemical reaction.

关键词： positive systems switched nonlinear systems stability

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非平衡度和闭合状态对磁控溅射离子镀过程的影响

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材料热处理学报 2009年第2期30卷 115-120页

作者：蒋百灵文晓斌栾亚丁小柯李显西安理工大学材料学院陕西西安710048

利用非平衡磁控溅射离子镀技术于不同磁控管非平衡度和磁场闭合状态下在单晶硅基体上制备出Cr镀层,采用扫描电子显微镜、X射线衍射仪分析了不同生长阶段Cr镀层的微观形貌、表面粗糙度和晶体择优生长趋势的变化。结果表明:磁控管非平衡... 详细信息

利用非平衡磁控溅射离子镀技术于不同磁控管非平衡度和磁场闭合状态下在单晶硅基体上制备出Cr镀层,采用扫描电子显微镜、X射线衍射仪分析了不同生长阶段Cr镀层的微观形貌、表面粗糙度和晶体择优生长趋势的变化。结果表明:磁控管非平衡和磁场闭合状态的改变显著影响着Cr镀层生长过程中的结晶取向、表面粗糙度和致密度。不同非平衡度下,Cr镀层组织为疏松的柱状晶体组织,镀层表面粗糙度随磁控管非衡度的增大而增大。随着磁场闭合程度的增加,Cr镀层组织由疏松的柱状晶体组织,向较致密的柱状晶体再向致密的无明显柱状晶体的组织转化,镀层晶体有沿低能量(110)晶面生长向高能量(200)晶面过渡择优生长的趋势。

关键词：磁控管非平衡度闭合状态磁控溅射离子镀粗糙度择优取向

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长江三角洲地区大气顶气溶胶直接辐射强迫遥感估算

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中国环境科学 2013年第5期33卷 799-807页

作者：肖钟湧江洪集美大学理学院福建厦门361021 南京大学国际地球系统科学研究所江苏南京210093 浙江农林大学亚热带森林培育国家重点实验室/浙江省森林生态系统碳循环与固碳减排重点实验室浙江杭州311300

利用MODIS和OMI卫星遥感数据估算长江三角洲地区大气顶气溶胶直接辐射强迫并分析其时空变化特征.结果表明了大气顶辐射强迫和气溶胶光学厚度(AOT)存在明显的线性相关关系,R和RMSE分别为0.89和5.50.大气顶辐射强迫的区域月平均变化范围... 详细信息

利用MODIS和OMI卫星遥感数据估算长江三角洲地区大气顶气溶胶直接辐射强迫并分析其时空变化特征.结果表明了大气顶辐射强迫和气溶胶光学厚度(AOT)存在明显的线性相关关系,R和RMSE分别为0.89和5.50.大气顶辐射强迫的区域月平均变化范围大约在-10--70W/m2之间,一年中最大值(-53.97±6.14W/m2)和AOT一样出现在6月,最小值(-16.41±2.10W/m2)出现在12月.4个季节的大小依次是:夏季(-44.30±9.09W/m2)>春季(-42.00±7.83W/m2)>秋季(-28.02±6.32W/m2)>冬季(-20.40±5.00W/m2).在6月,大气顶气溶胶辐射强迫空间差异最明显,在太湖沿岸的城市地区,如上海、杭州,辐射强迫可达-70W/m2,而在千岛湖地区大约为-10W/m2.在12月,空间差异最小,北部城市地区大约为-20 W/m2;南部地区大约为-10 W/m2.

关键词：气溶胶直接辐射强迫 MODIS OMI 地表反照率单次散射反照率

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