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A Facile Surface Passivation of Hematite Photoanodes with Molybdate Overlayers for Efficient PEC Water Oxidation

Chinese Journal of Chemical Physics 2018年第6期31卷 833-842,734页

作者： Qi Zhang Quan-ping Wu Yue Zhang Ji-tong Yan Song Xue Hong-yan Wang Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechanical System School of Mechanical Engineering Tianjin University of Technology Tianjin 300384 China Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion School of Chemistry & Chemical Engineering Tianjin University of Technology Tianjin 300384 China

α-Fe2O3 thin films have been synthesized and used as photoanodes for photo-electrochemical (PEC) water oxidation. Molybdate was introduced to mediate hematite thin films via two synthesis routes (namely in situin situ mediation and ex situ modification). Through the in situ mediation process, the morphology and film thickness could be changed significantly due to the addition of MoO42-, while for the ex situ modification, the PEC performance of the hematite has been greatly improved without changing the nanorod morphology. Various characterizations such as UV-Vis absorption, transmission electronic microscopy, scanning electronic microscopy, Mott-Schottky, electrochemical impedance spectroscopy were conducted and the PEC performances were investigated.

关键词： Hematite film Molybdate Passivation Water splitting Photocurrent

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Kinematic Analysis of a Redundant Actuated Five Degrees of Freedom Parallel Mechanism

Kinematic Analysis of a Redundant Actuated Five Degrees of F...

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2018 IEEE International Conference on Robotics and Biomimetics, ROBIO 2018

作者： Xiaolong, Yin Bin, Li Xinhua, Zhao Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control Tianjin University of Technology China Fac. of Natl. Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin300384 China

ISBN: (纸本)9781728103761

A 5 degree of freedom parallel mechanism with 6 branched redundant actuators is proposed. The mechanism is composed of 4 -SPS and 2-RPS kinematic branches. The mechanism can achieve three rotational and two translational motion. The performance of the forward and inverse kinematics, singularity and workspace, is analyzed, firstly, using the vector algebra method and Newton iteration method, the forward and inverse kinematics model were obtained from numerical solution and analytic solution;on this basis, get the Jacobian matrix of mechanism, and on the basis of the three kinds of performance parameters of matrix the singularity of the mechanism was analyzed;finally with the help of Monte Carlo method, obtaining the workspace of the mechanism. The related kinematic analysis will lay a theoretical foundation for the future study of the dynamics. © 2018 IEEE.

关键词： Mechanisms

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A Low SAR, Small size, High gain, Circularly polarized Antenna for Wearable Application

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Journal of Physics: Conference Series 2020年第1期1651卷

作者： Chao Wang Liang Zhang Yi Cheng XueMei Li Xianliang Wu Key Lab of Ministry of Education of Intelligent Computing & Signal Processing Anhui University Hefei Anhui 230601 China AnHui Province Key Laboratory of simulation and design for Electronic information system Hefei Normal university Hefei Anhui 230601 China

A planar, small size, high gain, low specific absorption rate (SAR) and circularly-polarized (CP) wearable antenna is proposed in this paper. The antenna is fabricated on a substrate with a dielectric constant of 3.5 with a thickness of 0.5 mm and sized at 42×42 mm only. Both the simulation results show that the overlap bandwidth of impedance and axial ratio of the proposed antenna is 13.7% (5.15-5.91 GHz). To isolate the antenna against the influence of the human body, a artificial magnetic conductor (AMC) plane is added on the reverse side of the radiator. The AMC structure effectively isolates the human body from the radiation of the antenna and reduces the specific absorption rate (SAR) of it by more than 96.1% at 5.5 GHz, which improves the antenna gain and the peak gain reaches 5.09 dBi at 5.5 GHz. The wearable performance of the antenna was analyzed, and it is observed that it can sustain good performance even under human body loading. Beside, the antenna has a small size, which makes it ideal for wearable applications.

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Influence of Micro-texture Parameters on Bone Drilling Force and Torque: A Finite Element Model

Influence of Micro-texture Parameters on Bone Drilling Force...

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2018 4th International Conference on Mechanical Engineering and Automation Science(ICMEAS2018)

作者： Yahui Hu Xiangjun Li Chuncheng Chen Lili Su QingchunZheng Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical EngineeringTianjin University of Technology

The micro-texture on the tool surface is an effective way to improve the quality of the drilling. While high-performance micro-texture plays an important role in improving the quality of working surface and prolonging the life of tool. In this study, a three-dimensional finite element model was established to study the relationship between drilling thrust, torque and microstructure parameters(micro-pit depth, micro-pit diameter and micro-pit spacing) during drilling of cortical bone. The model was validated by cortical bone drilling using a micro-structured tool. On basis of this, the thrust and torque prediction models of the micro-texture parameters were obtained. The results indicate that the thrust and torque increased with the increase of micro-pit diameter;while the increase of the micro-pit spacing caused the thrust and torque to decrease. When the depth of the micro-pit increased, the thrust and torque decreased first and then increased, and we found that the effect of micro-pit spacing and micro-pit depth on force and torque is insignificant.

关键词： Influence of Micro-texture Parameters on Bone Drilling Force and Torque A Finite Element Model

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Effect of tungsten on creep properties of martensitic 9Cr steel

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IOP Conference Series: Materials Science and Engineering 2020年第1期838卷

作者： F Y Hu S J Zhang J J Shen Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education (Tianjin University of Technology) China

The effects of tungsten on the creep behavior and microstructure of tempered martensite 9Cr steel with different W concentrations ranging from 0–2.5 wt% were studied. The matrix consisted of tempered lath martensite structure and M23C6 located along the grain boundary or inside the grain. As the W concentration increased, the number of M23C6 increased while the particle size decreased. Also, with the increasing W concentration, the minimum creep rate and elongation decreased while the time to rupture increased. The rise in W concentration led to the refinement of M23C6, which enhanced the creep strength but reduced the creep plasticity.

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Temperature control based on fuzzy-PID algorithm for the blackbody radiation source 15

Temperature control based on fuzzy-PID algorithm for the bla...

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15th IEEE International Conference on Mechatronics and Automation, ICMA 2018

作者： Wang, Zhigang Wang, Lingling Yun, Zerong Wang, Jinghui Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education China Tianjin University of Technology Tianjin China National Institute of Metrology China Beijing China

ISBN: (纸本)9781538660720

Blackbody radiation source is a key equipment in the traceability process of temperature measurement. In infrared temperature measurement, stable and consistent temperature control of the blackbody radiation sources is required. And in the process of calibration, it is a key element that a blackbody radiation source can produce a fixed temperature. Effective control of its temperature is, therefore, crucial. Due to the change of parameters and the uncertainty of loads, the performance requirements for conventional Proportional, Integral and Differential (PID) controller are high. But the control effect of the conventional PID controller on the temperature control system is not perfect. So the Fuzzy-PID control algorithm is simulated with software for the temperature control system of the blackbody radiation source in this paper. Compared with the conventional PID control algorithm, the Fuzzy-PID control has advantages of quicker response, smaller overshoot and more stable performance. It is of a certain reference value to improve the temperature control performances in the actual industrial production applications. © 2018 IEEE.

关键词： Temperature control

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Cooling Performance for Cylindrical Film-Cooling Hole with Divided Downstream Crescent-Shaped Block

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IOP Conference Series: Earth and Environmental Science 2020年第1期461卷

作者： Pengfei Zhang Zhiting Tong Fei Wang Linchao Bai Chao Zhang Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control Tianjin University of Technology Tianjin 300384 China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin 300384 China

The cooling performances for the cylindrical film-cooling hole with divided downstream crescent-shaped blocks were numerically investigated in present study. Four configurations with divided crescent-shaped block, i.e. linear, 30° convergence, 30° expansion, and 30° curved expansion, were studied at typical flow conditions. The successive crescent-shaped block case and the no block case were also solved in comparison. The temperature profiles, the local and lateral averaged cooling effectiveness at blowing ratios of 0.5 to 1.5 were obtained. As compared with the successive block case, the lateral coolant coverage were widened by using the divided block, and thus the lateral averaged cooling effectiveness were improved, especially at higher blowing ratios. Comparatively, the cylindrical hole with 30° expansion crescent-shaped block exhibited highest cooling performance.

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The temperature control of blackbody radiation source based on ADRC 15

The temperature control of blackbody radiation source based ...

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15th IEEE International Conference on Mechatronics and Automation, ICMA 2018

作者： Wang, Zhigang Yun, Zerong Wang, Lingling Wang, Jinghui Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin China Tianjin University of Technology Tianjin China Natinal Institute of Metrology China Beijing China

ISBN: (纸本)9781538660720

Blackbody radiation source is used as a standard device for infrared thermometer, it plays increasingly important roles in the field of calibration. Through experiment discoveries that it is a typical nonlinear system and has a large transport delay when the blackbody is rise temperature or cooling in order to reach set temperature points. Based on the temperature control of blackbody is a kind of typical multi-variable, strong coupling and time-varying nonlinear control system. The paper proposes applying the theory of active disturbance rejection controller (ADRC) to suppress various disturbances and improve the dynamic performance of blackbody radiation source. First of all, describing the working principle of blackbody radiation source and building its mathematical model. Secondly, introducing the control method of ADRC, which is applied to the temperature control system of blackbody radiation source. Finally, through MATLAB/SIMULINK platform to simulate and compare the temperature control performances of blackbody among ADRC, PID and Smith predictor(SP) control strategies. The simulation results show that proposed ADRC algorithm improves the abilities of anti-interference of system and it is without overshoot. In addition, the results also indicated that the control method of ADRC shortens plant stable time and has a strong prospect for practical applications. © 2018 IEEE.

关键词： Temperature control

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Study on Vibration and Crack Propagation Control of Cracked Asymmetric Rotor Based on Three-Dimensional Finite Element Model

Study on Vibration and Crack Propagation Control of Cracked ...

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IEEE International Conference on Mechatronics and Automation

作者： Rong Hu Jun Liu Jianen Chen Xiaofeng Wang Weimin Ge School of Mechanical Engineering Tianjin University of Technology Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechanical System Tianjin China

In order to solve the vibration problems of a cracked asymmetric rotor, the three-dimensional finite element model of the rotor is established combined with a nonlinear contact approach. The free interface modal synthesis method is applied to shorten the computation time by reducing the order of the model. The vibration characteristics of the asymmetric rotor and the cracked asymmetric rotor in different crack locations are analyzed by the simulation. The results of numerical simulation show the appearance of crack will affect the resonance frequency and the range of unstable area on the major critical speed. At the same time, the active control of the rotor is realized by the electromagnetic actuator controlled by neural network PID. Secondly, based on the theory of rotor dynamics, the effects of rotational speed and unbalance on the breathing behavior of the cracked rotor are discussed. In this paper, it proposes a novel method delaying the crack extension effectively. In the process of operation, the electromagnetic actuator (EMA) can effectively control the vibration and can delay the crack propagation.

关键词： Rotors Finite element analysis Mathematical model Solid modeling Computational modeling Vibrations Analytical models

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Detection of Weld Defects Based on Incremental Two-Dimensional Principal Component Analysis

Detection of Weld Defects Based on Incremental Two-Dimension...

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IEEE International Conference on Mechatronics and Automation

作者： Yaohua Shen Weimin Ge Xiaofeng Wang School of Mechanical Engineering Tianjin University of Technology Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechanical System Tianjin China

Aiming at the requirements of the real-time detection of weld defects in the industry, the candid covariance-free incremental PCA (CCIPCA) algorithm was introduced into the Two-Dimensional Principal Component Analysis (2PCA) algorithm, therefore an incremental 2DPCA algorithm (I2DPCA) is proposed. Firstly, the images captured by camera are preprocessed to improve the quality of the images because the captured images might be affected in the process of image acquisition. Then the 12DPCA algorithm is used to achieve feature extraction, and the dimension of the images is reduced. Finally, the recognition of weld defects is implemented using the k-nearest neighbor algorithm (KNN). Compared with the methods of traditional recognition by extracting the sizes of several geometric defects, the proposed algorithm has the advantage of the small memory spaces, the high recognition rate and the strong real-time recognition. The experimental results show that the proposed algorithm has higher recognition rate and is more practical than the 2DPCA, and the recognition rate reaches 94%, which can meet the requirements of the real-time detection.

关键词： Welding Feature extraction Covariance matrices Principal component analysis Histograms Image recognition Low pass filters

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