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Narrow and Dual-Band Tunable Absorption of a Composite Structure with a Graphene Metasurface

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Chinese Physics Letters 2017年第10期34卷 83-87页

作者：宁仁霞焦铮鲍婕 school of Information engineering Huangshan University Huangshan 245041 school of mechanical and electrical engineering Huangshan University Huangshan 245041

A tunable absorber, composed of a graphene ribbon on two layers of TiO2-Au between two slabs of dielectric material all on a metal substrate, is designed and numerically investigated. The absorption of the composite structure varies with the geometrical parameters of the structure and the physical parameters of graphene at mid-infrared frequencies. The numerical simulation shows that a near-perfect absorption with single and alum bands can be achieved in a certain frequency range. We also analyze the electric and surface current distributions to study the dual-band absorber. The results show that the absorber can be tuned by the chemical potential and electron phonon relaxation time of graphene, and electromagnetically induced transparency phenomenon can be obtained. The results of this study may be beneficial in the fields of infrared communication, perfect absorbers, sensors and filters.

关键词： ab Narrow and Dual-Band Tunable Absorption of a Composite Structure with a Graphene Metasurface THz LiF

An ADRC-based Active Heave Compensation for Offshore Rig

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An ADRC-based Active Heave Compensation for Offshore Rig

第32届中国控制与决策会议

作者： LIU Shuguang CHEN Wuyang WU Kecheng JIANG Jia school of mechanical and electrical eng.huangshan university Research and development center Anhui Dorje Electric Co. Ltd.

ISBN: (数字)9781728158556

ISBN: (纸本)9781728158563

Offshore drilling platform is a kind of offshore engineering structure,which provides operation and living space for the development and utilization of marine *** is a big difference between offshore drilling and land *** this process,the drilling platform floats on the fluctuating ocean surface,while the drill pipe carries the drill bit at depth of several *** the middle and deep sea areas,under the action of waves,the offshore drilling platform will not only sway around,but also rise and *** periodic upward and downward motion with wave will cause the periodic upward and downward motion of drill pipe *** upward and downward movement of drill pipe string will increase or decrease the hook tension,which will directly affect the change of bottom hole drilling *** the drilling pressure drops to a certain limit,the bit will be out of the bottom of the well and can not be drilled ***,in order to ensure the normal use of offshore drilling platform and improve drilling efficiency,it is necessary to adopt heave compensation system to reduce the relative movement of drill pipe string and seabed,and maintain constant tension load,reduce the impact of natural climate such as sea breeze,wave,current on drilling platform,and improve drilling efficiency and *** it can prolong the service life of drilling *** this paper,the working principle of offshore rig heave compensation system is given,and the design idea of the system is described in *** the speed control system lacks precise mathematical model and has the characteristics of non-linearity and variability,an ADRC control strategy is *** experimental results show that the controller can effectively control the compensation speed,has high control accuracy,strong antiinterference ability,is insensitive to parameter changes,and has a certain robustness.

关键词： offshore rig active heave compensation winch auto-disturbance rejection control

Numerical Simulation of Projection Welding Processes for Door Hinge of Automobile Based on Coupled Fields Analysis

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Journal of Shanghai Jiaotong university(Science) 2007年第1期12卷 111-115页

作者：钱昌明罗爱辉陈关龙 school of mechanical eng. Shanghai Jiaotong Univ.

Projection welding is a variation of electric resistance welding with the dynamic changes of the flow paths for heat and electrical properties with changing temperature caused by the large plastic deformation collapse of projection. As the joint type between the auto door hinge and the inner plate, projection welding may bring welding distortions and would affect the assembly quality of auto body. A comprehensive electric-thermal-mechanical numerical simulation was performed to quantitatively simulate the processes of projection welding by using a coupled finite element method. The mechanism of projection collapse and the formation process of nugget were discussed and good conclusions have been achieved comparing with the test results.

关键词： projection welding coupled finite element method(FEM) numerical simulation

Design of Intelligent Power Capacitor with Synchronous Switching

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Design of Intelligent Power Capacitor with Synchronous Switc...

第40届中国控制会议

作者： LIU Shuguang ZHAO Wenpu SONG Tianle SHAO Wenquan GAO Yi school of mechanical and electrical eng. Huangshan University Xi'an Aerospace Automation Co. Ltd.

An intelligent power capacitor with synchronous switching is designed, which can quickly switch on and off the reactive compensation capacitor. By accurately calculating the time of voltage zero-crossing and current zero-crossing, and making intelligent prediction in advance, the precise zero-crossing synchronous switching can be completed, that is, the magnetic latching relay can be put into operation in advance before the voltage zero-crossing, so that its contact can be closed exactly at the time of voltage zero-crossing, so that the capacitor can be connected without inrush current, and the magnetic latching relay can be cut off in advance before the current zero-crossing, so that the capacitor can be disconnected without arc. Compared with the traditional reactive power compensation method, which uses AC contactor switching and fast electronic switching, synchronous switching technology can greatly reduce the inrush current and arc generated during switching, and further improve the safety and reliability of power capacitor.

关键词： reactive power compensation power capacitor synchronous switching thyristor latching relay

Characterization of hot deformation and microstructure evolution of a new metastableβtitanium alloy

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Transactions of Nonferrous Metals Society of China 2022年第5期32卷 1513-1529页

作者： Zhao-qi CHEN Li-juan XU Shou-zhen CAO Jian-kai YANG Yun-fei ZHeng Shu-long XIAO Jing TIAN Yu-yong CHEN National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of TechnologyHarbin 150001China school of Materials Science and engineering Harbin Institute of TechnologyHarbin 150001China College of mechanical and electrical engineering Huangshan UniversityHuangshan 245021China

The hot deformation characteristics of as-forged Ti−3.5Al−5Mo−6V−3Cr−2Sn−0.5Fe−0.1B−0.1C alloy within a temperature range from 750 to 910℃and a strain rate range from 0.001 to 1 s^(-1) were investigated by hot compression *** stress−strain curves show that the flow stress decreases with the increase of temperature and the decrease of strain *** microstructure is sensitive to deformation *** dynamic recrystallization(DRX)grains appear while the temperature reaches 790℃at a constant strain rate of 0.001 s^(-1) and strain rate is not higher than 0.1 s^(-1) at a constant temperature of 910℃.The work-hardening rateθis calculated and it is found that DRX prefers to happen at high temperature and low strain *** constitutive equation and processing map were *** average activation energy of the alloy is 242.78 kJ/mol and there are few unstable regions on the processing map,which indicates excellent hot *** the strain rate of 0.1 s^(-1),the stress−strain curves show an abnormal shape where there are two stress peaks *** can be attributed to the alternation of hardening effect,which results from the continuous dynamic recrystallization(CDRX)and the rotation of DRX grains,and dynamic softening mechanism.

关键词： metastableβtitanium alloy hot deformation behavior microstructure evolution abnormal flow behavior

An Active Endoscopy Robotic System for Direct Tracheal Inspection

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Journal of Shanghai Jiaotong university(Science) 2007年第2期12卷 159-163页

作者：于莲芝颜国正马官营昝鹏 school of Electronic Information and Electrical Eng.Shanghai Jiaotong Univ.

The development of active endoscopy techniques is one important area of medical *** paper designed a new flexible and active endoscopy robotic system for direct tracheal *** mobile mechanism of the robot is based on the inchworm movement actuated by pneumatic rubber *** are five air chambers controlled independently,by adjusting pressures in air chambers,the robot can move in a straight mode or in a bending *** inspection sensors and some therapy surgery tools can be equipped in the front of the *** prototype was made and its mechanical characteristics were *** robot could move smoothly in a small plastic tube,and the robot is respectable to be used for inspection in human trachea directly.

关键词： active endoscopy robotic system pneumatic rubber actuator flexible mechanism human trachea inspection

Analysis on the process parameters impact on the temperature of friction stir jointing process for 7022 aluminum alloy

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Analysis on the process parameters impact on the temperature...

第八届中国功能材料及其应用学术会议

作者： WANG Hong-feng ZUO Dun-wen WANG Jian-li WANG Ming SONG Wei-wei school of mechanical Electronic & Information engineering Huangshan University College of mechanical and electrical engineering Nanjing University of Aeronautics and Astronautics

Considered the forces acting on tool and the friction coefficient between the shoulder and tool and the internal materials of workpiece changing with the temperature,the heat source model was *** temperature field of friction stir jointing process was simulated by the *** simulation results show that the temperature in advancing side is higher than in retreating *** peak of heat cycle curve is gradually decreased from the surface to the bottom of *** rotation speed on the peak of heat cycle curve effect is small,and the feed speed is large.

关键词： friction stir jointing temperature field 7022 aluminum alloy finite element simulation heat source model

Fracture Mechanics for a Mode Ⅲ Crack in a Piezoelectromagnetic Material

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Journal of Shanghai Jiaotong university(Science) 2005年第3期10卷 293-297页

作者：胡克强李国强 school of mechanical eng. Tianjin Univ.Tianjin 300072China College of Civil eng. Tongji Univ. Shanghai 200092

Analytical solutions for a Griffith crack inside an infinite piezoel ectromagnetic medium under combined mechanical-electrical-magnetic loadings are formulated using integral transform method. The singular stress, electric and magnetic fields in the piez oelectromagnetic material are obtained by the theory of linear piezoelectromagneticity. Fourier transforms are used to reduce the mixed boundary value problems of the crack, which is assumed to b e permeable, to dual integral equations. The solution of the dual integral equations is then ex pressed analytically. Expressions for strains, stresses, electric fields, electric displacements, mag netic fields and magnetic inductions in the vicinity of the crack tip are derived. Field intensi ty factors and energy release rate for piezoelectromagnetic material are obtaine d. The stresses, electric displacements and magnetic inductions at the crack tip show the traditional square root singu larities; and the electric field intensity factor (EFIF) and the magnetic field intensity factor (MFIF) are always zero.

关键词： piezoelectromagnetic crack integral transform method permeable

An experimental study of elastic properties of dragonfly-like flapping wings for use in biomimetic micro air vehicles(BMAVs)

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Chinese Journal of Aeronautics 2017年第2期30卷 726-737页

作者： Praveena Nair Sivasankaran Thomas Arthur Ward Erfan Salami Rubentheren Viyapuri Christopher J.Fearday Mohd Rafie Johan Department of mechanical engineering University of Malaya KuaIa Lumpur 50603 Malaysia school of engineering and Physical Sciences Heriot-Watt University Malaysia Putrajaya 62200 Malaysia Department of electrical engineering University of Malaya Kuala Lumpur 50603 Malaysia

This article studies the elastic properties of several biomimetic micro air vehicle（BMAV）wings that are based on a dragonfly *** are a new class of unmanned micro-sized air vehicles that mimic the flapping wing motion of flying biological organisms（e.g.,insects,birds,and bats）.Three structurally identical wings were fabricated using different materials：acrylonitrile butadiene styrene（ABS）,polylactic acid（PLA）,and *** wing frame structures were fabricated from these materials and then a nanocomposite film was adhered to them which mimics the membrane of an actual *** wings were then attached to an electromagnetic actuator and passively flapped at frequencies of 10-250 Hz.A three-dimensional high frame rate imaging system was used to capture the flapping motions of these wings at a resolution of 320 pixels x 240 pixels and 35000 frames per *** maximum bending angle,maximum wing tip deflection,maximum wing tip twist angle,and wing tip twist speed of each wing were measured and compared to each other and the actual dragonfly *** results show that the ABS wing has considerable flexibility in the chordwise direction,whereas the PLA and acrylic wings show better conformity to an actual dragonfly wing in the spanwise *** studies have shown that the aerodynamic performance of a BMAV flapping wing is enhanced if its chordwise flexibility is increased and its spanwise flexibility is ***,the ABS wing（fabricated using a 3D printer） shows the most promising results for future applications.

关键词： ABS Acrylic Biomimetic micro air vehicle Flapping mechanism PLA Wing structure