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torque and bending moment acting on a flexible shaft agitated by disk turbines in a gas–liquid stirred vessel

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Chinese Journal of Chemical Engineering 2019年第4期27卷 781-793页

作者： Yangyang Liang Zhengming Gao Dai'en Shi Haotian Li Yuyun Bao Ziqi Cai State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical Technology Beijing 100029 China Mechanical Engineering School Yancheng Institute of Technology Yancheng 224051 China

The torque and bending moment acting on a flexible overhung shaft in a gas–liquid stirred vessel agitated by a Rushton turbine and three different curved-blade disk turbines(half circular blades disk turbine, half elliptical blades disk turbine, and parabolic blades disk turbine) were experimentally measured by a customized moment sensor. The results show that the amplitude distribution of torque can be fitted by a symmetric bimodal distribution for disk turbines, and generally the distribution is more dispersive as the blade curvature or the gas flow rate increases. The amplitude distribution of shaft bending moment can be fitted by an asymmetric Weibull distribution for disk turbines. The relative shaft bending moment manifests a "rising-falling-rising" trend over the gas flow number, which is a corporate contribution of the unstable gas–liquid flow around the impeller, the gas cavities behind the blades, and the direct impact of gas on the impeller. And the "falling" stage is greater and lasts wider over the gas flow number for Rushton turbine than for the curved-blade disk turbines.

关键词： Shaft bending moment torque Disk turbines Gas–liquid flow Fluid structure interaction

Bio-signal based elbow angle and torque simultaneous predictionduring isokinetic contraction

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Science China(Technological Sciences) 2019年第1期62卷 21-30页

作者： ZHOU Yu LIU JingBiao ZENG Jia LI KaiRu LIU HongHai State Key Laboratory of Mechanical System and Vibration School of Mechanical Engineering Shanghai Jiao Tong University School of Computing The University of Portsmouth

It is of great importance to decode motion dynamics of the human limbs such as the joint angle and torque in order to improve the functionality and provide more intuitive control in human-machine collaborative systems. In order to achieve feasible prediction,both the surface electromyography(sEMG) and A-mode ultrasound were applied to detect muscle deformation and motor *** abled subjects were recruited to perform five trails elbow isokinetic flexion and extension, and each trail contained five repetitions, with muscle deformation and s EMG signals recorded simultaneously. The experimental datasets were categorized as:the ultrasound-EMG combined datasets, ultrasound-only datasets and EMG-only datasets. The support vector machine(SVM)regression model was developed for both elbow joint angle and torque prediction, based on the above three kinds of datasets. The root-mean-square error(RMSE) and the correlation coefficients(R) were applied to evaluate the prediction accuracy. The results across all the subjects for different datasets indicated that the combined datasets and the ultrasound datasets were superior to the sEMG datasets both on elbow joint angle and torque prediction, and there were no significant differences between the combined datasets and the ultrasound datasets. It turns out that elbow angle and torque can be reconstructed by A-mode ultrasound, and the significant findings pave the way towards the application of musculature-driven human-machine collaborative systems.

关键词： angle torque surface electromyography (sEMG) ultrasound support vector machine (SVM) regression isokinetic contraction

Mathematical Model of Drag torque with Surface Tension in Single-Plate Wet Clutch

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Chinese Journal of Mechanical Engineering 2019年第2期32卷 93-99页

作者： Zengxiong Peng Shihua Yuan National Key Laboratory of Vehicular Transmission Beijing Institute of Technology

Reduction of drag torque in disengaged wet clutches is essential for transmission research because it is one of the potentials of e ciency improvement. Aeration of oil film between two closely rotating plates promotes the decrease of drag torque at high speed region. The e ects of surface tension and static contact angles during aeration are nonnegligible showed by test results. The traditional lubrication model does not adequately predict the experimental results with di erent surface tension and contact angles during aeration. Hence, in this present paper, contact angles between Aluminum and Teflon materials were firstly measured, and the drag torques under two di erent contact angles were examined experimentally. An improved lubrication model of drag torque based on Navier–Stokes equations at the gas-liquid interface was built. The lubrication boundary condition was modified to introduce the e ects of surface tension and contact angle. The model shows that the e ects at the beginning of aeration of oil film are significant. These e ects almost occur at stationary plate due to low Reynolds number and Weber number. The model shows that an increase in the surface tension promotes aeration, but does not a ect the peak drag torque. Increasing contact angle also promotes the aeration, and accelerates the decrease of drag torque. The larger contact angle is, the smaller the peak drag torque will be. A computational fluid dynamics(CFD) model based on volume of fluid(VOF) method was presented to validate the interface shape when aeration occurs. The model prediction has a good agreement with experimental observations for Aluminum plates and Teflon plates. The modified lubrication model of drag torque gives a convenient description of the e ects of surface tension and contact angel, and lays down a frame to understand the beginning of aeration.

关键词： Drag torque Wet clutch Surface tension Contact angle

Calculation of Neutral Beam Injected torque and Its Effective Tangency Major Radius for EAST

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Plasma Science and Technology 2015年第7期17卷 545-551页

作者：伍兴权万宝年吕波吴斌王进芳胡纯栋 Institute of Plasma Physics Chinese Academy of Sciences

Toroidal rotation has been recognized to have significant effects on the transport and magnetohydrodynarnic（MHD） stability of tokamak *** beam injection（NBI） is the most effective rotation generation method on current,tokamak *** estimate the effective injected torque of the first neutral beam injection system on EAST,a simplified analytic method was *** beam torque values were validated by those obtained from the NUBEAM code *** to the results,for the collisional torque,the effective tangential radius for torque deposition is close to the beam tangency major ***,due to the dielectric property of tokamak plasma,the equivalent tangency major radius of the J×B torque is equal to the average major radius of the magnetic flux *** results will be useful for the research of toroidal momentum confinement and the experimental analysis of momentum transport related with NBI on EAST.

关键词： neutral beam injection torque tangency major radius NUBEAM

torque teno virus in liver diseases: On the way towards unity of view

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World Journal of Gastroenterology 2020年第15期26卷 1691-1707页

作者： Vasiliy I Reshetnyak Igor V Maev Alexandr I Burmistrov Igor A Chekmazov Tatiana I Karlovich Department of Propaedeutic of Internal Diseases and Gastroenterology A.I.Yevdokimov Moscow State University of Medicine and DentistryMoscow 127473Russia Central Clinical Hospital with Polyclinic Presidential Administration of the Russian FederationMoscow 121359Russia

The review presents the data accumulated for more than 20 years of research of torque teno virus(TTV).Its molecular genetic structure,immunobiology,epidemiology,diagnostic methods,possible replication sites,and pathogenicity factors are *** is a virus that is frequently detectable in patients with different viral hepatitides,in cases of hepatitis without an obvious viral agent,as well as in a healthy *** is evidence suggesting that biochemical and histological changes occur in liver tissue and bile duct epithelium in TTV *** are sufficient histological signs of liver damage,which confirm that the virus can undergo a replicative cycle in *** with this,cytological hybridization in TTV-infected cells has shown no substantial cytopathic(cell-damaging)effects that are characteristic of pathogenic hepatotropic *** TTV has led to the evolution of views on its role in the development of human *** first ideas about the hepatotropism of the virus were gradually reformed as new data became available on the prevalence of the virus and its co-infection with other viruses,including the viruses of the known types of *** high prevalence of TTV in the human population indicates its persistence in the body as a virome and a nonpathogenic *** has recently been proposed that the level of TTV DNA in the blood of patients undergoing organ transplantation should be used as an endogenous marker of the body’s immune *** available data show the polytropism of the virus and deny the fact that TTV can be assigned exclusively to hepatitis ***,the rare detection of the damaging effect of TTV on hepatic and bile duct epithelial cells may be indirect evidence of its conditionally pathogenic *** ubiquity of the virus and the variability of its existence in humans cannot put an end to its study.

关键词： torque teno virus Prevalence of torque teno virus torque teno virus in liver disease Virome and torque teno virus torque teno virus and human immune status

Change monitoring of earth rotation parameter with Maglev gyroscope precessional torque

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中国有色金属学会会刊：英文版 2011年第S3期21卷 589-593页

作者： YANG Zhi-qiang, GONG Yun, SHI Zhen, LI Yun Geological Engineering and Geomatics Institute, Chang’an University, Xi’an 710054, China Geological Engineering and Geomatics Institute Chang'an University Xi'an 710054 China

Through analyzing the relationship between gyro dynamic torques produced by the changes of earth rotation parameters (ERP), a method of measuring the earth rotation parameters was proposed and explored by using gyroscope. The preliminary experiments were carried out using GAT Maglev Gyro Station (which is self-developed by China). Considering the measurement and expanding-application of the earth rotation parameters, some ideas and opinions about the structure design, measurement methods and data processing of gyro were proposed, and some outlook of the expanding-application of the gyroscope in geodetic and geophysical fields were done. The experimental results show that using the high-precision gyroscope to determine the changes of ERP is feasible, with the emergence of ultra-high precision gyro; it is possible for determining the earth rotation parameters by gyro in stead of by current complex space surveying technology.

关键词： Maglev gyroscope earth rotation parameters (ERP) precessional torque pole motion length of day

Spin torque nano-oscillators with a perpendicular spin polarizer

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Chinese Physics B 2019年第3期28卷 60-70页

作者： Cuixiu Zheng Hao-Hsau Chen Xiangli Zhang Zongzhi Zhang Yaowen Liu Shanghai Key Laboratory for Special Artificial Microstructure Materials and Technology School of Physics Science and EngineeringTongji UniversityShanghai 200092China Department of Optical Science and Engineering Fudan UniversityShanghai 200433China

We present an overview in the understanding of spin-transfer torque(STT) induced magnetization dynamics in spintorque nano-oscillator(STNO) devices. The STNO contains an in-plane(IP) magnetized free layer and an out-of-plane(OP) magnetized spin polarizing layer. After a brief introduction, we first use mesoscopic micromagnetic simulations,which are based on the Landau–Lifshitz–Gilbert equation including the STT effect, to specify how a spin-torque term may tune the magnetization precession orbits of the free layer, showing that the oscillator frequency is proportional to the current density and the z-component of the free layer magnetization. Next, we propose a pendulum-like model within the macrospin approximation to describe the dynamic properties in such type of STNOs. After that, we further show the procession dynamics of the STNOs excited by IP and OP dual spin-polarizers. Both the numerical simulations and analytical theory indicate that the precession frequency is linearly proportional to the spin-torque of the OP polarizer only and is irrelevant to the spin-torque of the IP polarizer. Finally, a promising approach of coordinate transformation from the laboratory frame to the rotation frame is introduced, by which the nonstationary OP magnetization precession process is therefore transformed into the stationary process in the rotation frame. Through this method, a promising digital frequency shift-key modulation technique is presented, in which the magnetization precession can be well controlled at a given orbit as well as its precession frequency can be tuned with the co-action of spin polarized current and magnetic field(or electric field) pulses.

关键词： spin torque nano-oscillators(STNOs) spin-transfer torque effect magnetic simulation

Interference torque of a three-floated gyroscope with gas-lubricated bearings subject to a sudden change of the specific force

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Chinese Journal of Aeronautics 2019年第3期32卷 737-747页

作者： Yan LI Fuhai DUAN School of Mechanical Engineering Dalian University of Technology

A numerical study is carried out to investigate the influence of a sudden change of the specific force on a three-floated gyroscope with a rotor supported on gas-lubricated *** interference torque is calculated to evaluate the influence by modeling the transient behavior of the rotor-bearing system. In combination with dynamic equations of the rotor displacement,the Reynolds equation is solved on the surface of spiral-grooved conical bearings. It is assumed that a steady state has been obtained with a constant specific force, and then the specific force is suddenly changed and maintained constant after that. Responses of the sudden change are obtained by solving the equations. Numerical results show that the direction of the sudden change of the specific force is the main factor which influences the interference torque curve. With a sudden change along the input direction, the interference torque fluctuation has a constant frequency and a decreasing amplitude. With a sudden change along the output direction, the interference torque fluctuates in a small range. With a sudden change along the spin direction, the change of the interference torque combines a fluctuation and a gradually-changing quasi-equilibrium value. This study provides a supplement to the steady-state error model of the three-floated gyroscope.

关键词： Conical bearing Gas lubricated bearings Interference torque Rotor-bearing system Three-floated gyroscope

Fuzzy torque Control of the Bionic Flexible Manipulator Actuated by Pneumatic Muscle Actuators

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Chinese Journal of Mechanical Engineering 2019年第5期32卷 80-94页

作者： Kai Liu Yining Chen Jiaqi Xu Yang Wu Yonghua Lu Dongbiao Zhao College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and Astronautics

A bionic flexible manipulator driven by pneumatic muscle actuator(PMA)can better reflect the flexibility of the *** research on PMA mainly focuses on the modeling and control strategy of the pneumatic manipulator *** with traditional electro-hydraulic actuators,the structure of PMA is simple but possesses strong nonlinearity and flexibility,which leads to the difficulty in improving the control *** this paper,the configuration design of a bionic flexible manipulator is performed by human physiological map,the kinematic model of the mechanism is established,and the dynamics is analyzed by Lagrange method.A fuzzy torque control algorithm is designed based on the computed torque method,where the fuzzy control theory is *** hardware experimental system is *** the co-simulation contrast test on MATLAB and ADAMS,it is found that the fuzzy torque control algorithm has better tracking performance and higher tracking accuracy than the computed torque method,and is applied to the entity control *** experimental results show that the fuzzy torque algorithm can better control the trajectory tracking movement of the bionic flexible *** research proposes a fuzzy torque control algorithm which can compensate the error more effectively,and possesses the preferred trajectory tracking performance.

关键词： Pneumatic muscle actuator Bionic flexible manipulator Computed torque method Fuzzy torque control