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Realizing mode conversion and optical diode effect by coupling photonic crystal waveguides with cavity

Chinese Physics B 2015年第9期24卷 284-288页

作者：叶寒张金倩楠俞重远王东林陈智辉 State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and Telecommunications Theoretical Condensed Matter Physics and Computational Materials Physics Laboratory School of PhysicsUniversity of Chinese Academy of Sciences Key Laboratory of Advanced Transducers and Intelligent Control System Ministry of Education and Shanxi ProvinceTaiyuan University of Technology

We propose a novel two-dimensional photonic crystal structure consisting of two line defect waveguides and a cavity to realize mode conversion based on the coupling effect. The W1/cavity/W2 structure breaks the spatial symmetry and successfully converts the even（odd） mode to the odd（even） mode in the W2 waveguide during the forward（backward）transmission. When considering the incidence of only the even mode, the optical diode effect emerges and achieves approximate 35 d B unidirectionality at the resonant frequency. Moreover, owing to the narrow bandpass feature and the flexibility of the tuning cavity, utilization of the proposed structure as a wavelength filter is demonstrated in a device with a Y-branch splitter. Here, we provide a heuristic design for a mode converter, optical diode, and wavelength filter derived from the coupling effect between a cavity and adjacent waveguides, and expect that the proposed structure can be applied as a building block in future all-optical integrated circuits.

关键词： mode conversion optical diode photonic crystal

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Research on the Performance of Hydraulic Excavator with Pump and Valve Combined Separate Meter In and Meter Out Circuits

Research on the Performance of Hydraulic Excavator with Pump...

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2015 International Conference on Fluid Power and Mechatronics

作者： Lei Ge Zhixin Dong Weinan Huang Long Quan Jing Yang Wenyong Li Taiyuan University of Technology Key Lab of Advanced Transducers and Intelligent Control System of Ministry of Education

Conventional hydraulic actuator is controlled by mechanically connected orifices valve. The controllability of this method is poor and the energy consumption is huge especially under the over-running condition. So a novel system configuration of the hydraulic excavator is presented to improve the problem mentioned above, in which boom cylinder, stick cylinder and swing motor are controlled with separate meter in and meter out technology, bucket cylinder and travel motors are controlled with conventional valves. Firstly, the paper provides a comprehensive review on the development of the separate meter in and meter out technology. Then the principles of load sensing system and SMISMO system applied on the excavator are illustrated though two diagram to show the difference of the two systems. And then a virtual prototype based on the real physical structures is established, which consists of the hydraulic excavator mechanical structure with multi-body dynamics and electro-hydraulic system. The model is verified by the statics and dynamics experiments. Then the dynamic, static performances as well as the energy consumption characteristics of the boom, arm and swing actuators are investigated under the condition of load sensing hydraulic system and the proposed system using the virtual prototype. The control strategy of the actuators is formulated according to their load condition and operation characteristics also based on the detailed analysis. After that, the physical prototype based on the proposed configuration system is established and its performance is tested. The experimental results show that the accuracy of the virtual prototype is validated;the proposed configuration system can significantly decreases the pressure losses through the valve and improve the energy efficiency of the machine;the pressure shocks within hydraulic actuators is decreased as well, thus the stationarity of the whole machine is improved accordingly.

关键词： flow matching separate meter in and meter out pressure and flow combined control pump and valve hybrid control

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Study on optical nonlinearity and optical limiting property of porphyrin-oxygenated carbon nanomaterial blends

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Optoelectronics Letters 2015年第3期11卷 161-165页

作者：温浩张校亮刘智波鄢小卿李晓春田建国 Key Laboratory of Advanced Transducers and Intelligent Control System Ministry of Education Taiyuan University of Technology College of Physics and Optoelectronics Taiyuan University of Technology Key Laboratory of Weak Light Nonlinear Photonics Ministry of Education Teda Applied Physics School and School of Physics Nankai University

Stable porphyrin-oxygenated carbon nanomaterial dispersions were prepared by blending porphyrin solutions with hydroxyl groups modified multi-walled carbon nanotubes(MWNTs-OH)and graphene oxide(GO)dispersions,*** nonlinearity and optical limiting(OL)property of these blends are investigated in nanosecond *** show that the OL performance of the blends can be tuned by changing the concentrations ratio of porphyrin and oxygenated carbon *** high concentration of oxygenated carbon nanomaterial leads to the poor OL ***,with the moderate concentration,the blends exhibit the low threshold value of OL and the enhanced OL performance at high fluence *** superior OL performance can be attributed to complementary mechanisms and possible photoinduced electron or energy transfer between porphyrin moiety and oxygenated carbon nanomaterials.

关键词： Blending Carbon Dispersions Energy transfer Graphene Nanostructured materials Nonlinear optics Optical properties Porphyrins Yarn

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Dynamic hazard of belt transport tracking and discerning method based on mean shift

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International Journal of Mining and Mineral Engineering 2015年第4期6卷 309-320页

作者： Qiao, Tiezhu Duan, Yanfei Key Lab of Advanced Transducers and Intelligent Control System Ministry of Education and Shanxi Province Taiyuan University of Technology Taiyuan030024 China

For the conveyer belt in coal mine often damaged by hazards such as stones or metals in transit which can cause a longitudinal tear, and the feature of hazards' status changed when transportation belt being torn, a Mean shift tracking and monitoring method was approached. Infrared spectrum imaging model was established for hazard, and extracted hazard grey value according to reflected background radiation differences between hazard and coal in the best wavelength range. Hazard model is established using grey space joint histogram, Mean shift vector is established with bandwidth matrix and recursive equations are given in EM like manner. Experiments show that when hazards tearing the tape, the algorithm can be real-time tracking and monitoring the state of hazards to determine the tape tear. © 2015 Inderscience Enterprises Ltd.

关键词： Image processing

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Characteristics of a Piloted Digital Flow Valve Based on Flow Amplifier

Characteristics of a Piloted Digital Flow Valve Based on Flo...

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2015 International Conference on Fluid Power and Mechatronics

作者： Taotao Li Jiahai Huang Yanhong Bai Long Quan Shengguo Wang Key Lab of Advanced Transducers and Intelligent Control System Ministry of Education and Shanxi ProvinceTaiyuan University of Technology

Hydraulic switching techniques which have less throttling losses, good repeatability and can be controlled intelligently have been largely developed. The biggest challenge is the hydraulic fluctuation. It is generated in the process of opening and closing the valve. A two-stage digital flow valve operated by Pulse Width Modulation(PWM) signal is studied in this paper. The main stage is cartridge valve based on flow amplifying principle;the pilot stage is high-speed on/off valve. The fluctuation characteristic of the digital flow valve is investigated using theoretical derivation and simulation analysis. The results show that the outlet flow fluctuation is influenced by many parameters such as the frequency and duty ratio of PWM signal, the volume of control chamber, etc. It can be weakened through the proper design of these parameters. Although the fluctuation exists, the mean outlet flow can be proportionally controlled by adjustment of the duty ratio of the control signal.

关键词： Flow valve,High-speed on/off valve,PWM,cartridge valve

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Research on the performance of hydraulic excavator with pump and valve combined separate meter in and meter out circuits

Research on the performance of hydraulic excavator with pump...

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International Conference on Fluid Power and Mechatronics (FPM)

作者： Lei Ge Zhixin Dong Weinan Huang Long Quan Jing Yang Wenyong Li Taiyuan University of Technology Key Lab of Advanced Transducers and Intelligent Control System of Ministry of Education Taiyuan China

ISBN: (纸本)9781479987719

Conventional hydraulic actuator is controlled by mechanically connected orifices valve. The controllability of this method is poor and the energy consumption is huge especially under the over-running condition. So a novel system configuration of the hydraulic excavator is presented to improve the problem mentioned above, in which boom cylinder, stick cylinder and swing motor are controlled with separate meter in and meter out technology, bucket cylinder and travel motors are controlled with conventional valves. Firstly, the paper provides a comprehensive review on the development of the separate meter in and meter out technology. Then the principles of load sensing system and SMISMO system applied on the excavator are illustrated though two diagram to show the difference of the two systems. And then a virtual prototype based on the real physical structures is established, which consists of the hydraulic excavator mechanical structure with multi-body dynamics and electro-hydraulic system. The model is verified by the statics and dynamics experiments. Then the dynamic, static performances as well as the energy consumption characteristics of the boom, arm and swing actuators are investigated under the condition of load sensing hydraulic system and the proposed system using the virtual prototype. The control strategy of the actuators is formulated according to their load condition and operation characteristics also based on the detailed analysis. After that, the physical prototype based on the proposed configuration system is established and its performance is tested. The experimental results show that the accuracy of the virtual prototype is validated; the proposed configuration system can significantly decreases the pressure losses through the valve and improve the energy efficiency of the machine; the pressure shocks within hydraulic actuators is decreased as well, thus the stationarity of the whole machine is improved accordingly.

关键词： Valves Actuators Prototypes Energy consumption Cavity resonators Load modeling

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Transient Flow Field Characteristic Analysis of Poppet Valve Based on Dynamic Mesh 6DOF Technique

Transient Flow Field Characteristic Analysis of Poppet Valve...

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2015 International Conference on Fluid Power and Mechatronics

作者： Guo Xiao-xia Huang Jia-hai Quan Long Wang Sheng-guo Key Lab of Advanced Transducers and Intelligent Control System Ministry of Education and Shanxi ProvinceTaiyuan University of Technology

In the fluid engineering, many projects involve movement and deformation of the boundary, but it is difficult to describe them by a simple algebraic expression because the movement of the boundary is determined by the force of hydraulic pressure, torque and other force which work together on the boundary. However, the previous numerical analyses are limited to the steady method or directly giving a speed to the spool which is difficult to actually simulate the movement of the spool. This paper developed a 6DOF model of a threedimensional poppet valve to stimulate the transient flow field in the opening process by means of computational fluid dynamics software—Fluent. The movement of the spool is decided by fluid force which exert on it and its gravity. By comparing numerical simulation results of the valve displacement, pressure of the control chamber and the inlet and outlet flow rate of poppet valve with the experimental results, the numerical results are the same as the experimental results. So the method that the paper proposed is feasible and more truly to simulate the flow state in the opening process of hydraulic valve. And on this basis, the pressure field, velocity field and flow regime are researched when poppet valve reaches steady state, which provides an important theoretical basis for further research on hydraulic valve performance.

关键词： poppet valve numerical calculation Dynamic Mesh Fluent

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Research on the performance of electro-hydraulic proportional flow valve controlled by pilot pump

Research on the performance of electro-hydraulic proportiona...

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International Conference on Fluid Power and Mechatronics (FPM)

作者： Yunxiao Hao Jiahai Huang Wenyong Li Long Quan Bin Zhao Key Laboratory of Advanced Transducers and Intelligent Control System Taiyuan University of Technology Taiyuan Shanxi China

ISBN: (纸本)9781479987719

Cartridge flow valves, widely applied in heavy machine and equipment, have the advantages of low leakage, large flow capacity, and simple structure. However, in the existence technologies, in order to reduce the influence of load variety on valve flow, a pressure differential compensator or a cartridge type flow sensor should be added to proportional throttle valve. This method reduces valve flow capacity and increases system throttling loss. In large flow occasion, flow only can be indirectly controlled by changing valve opening area for the limitation of the structure. So a low energy consumption, high controllable electro-hydraulic proportional valve which is structured by a hydraulic transistor (Valvistor) and a small displacement hydraulic pump driven by a servo motor is introduced. Based on the Valvistor valve flow amplification principle, main valve flow is controlled by pilot pump flow which is controlled by changing rotation speed without the influence of load variety. In the research, it's known from the analysis of the new principle valve steady flow characteristics that feedback throttle slot pre-opening will cause the decrease of the main valve flow as pressure drop increases. Soa method of pressure differential-pilot pump rotation speed compensation is put forward and it can obtain ideal flow characteristic. Then the dynamic mathematical model is established and the main valve stability criterion is derived. The influence of the valve parameters on main valve performance is analyzed and simulated. The results provide a new method for the large flow electro-hydraulic proportional control system.

关键词： Valves Mathematical model Analytical models Load modeling Force Stability criteria

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Chaotic light generation and its application in communication, sensor, radar

Chaotic light generation and its application in communicatio...

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International Conference on Optical Communications and Networks (ICOCN)

作者： Mingjiang Zhang Anbang Wang Yuncai Wang Key Lab of Advanced Transducers and Intelligent Control System Ministry of Education and Shanxi Province Taiyuan University of Technology Taiyuan Shanxi CN

Chaotic light has aroused considerable interest owing to its wide applications. Semiconductor laser, subject to optical feedback, optical injection, or optoelectronic feedback, can readily emit large-amplitude optical chaotic signals, and hence become the most suitable chaotic light sources. This paper illustrates the chaotic light generation based on semiconductor laser and its application in optical time domain reflectometry, distributed fiber sensing and photonic UWB radar.

关键词： Chaotic communication Optical feedback Optical fibers Optical attenuators Optical fiber sensors Optical reflection

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Research on the Performance of Electro-hydraulic Proportional Flow Valve controlled by Pilot Pump

Research on the Performance of Electro-hydraulic Proportiona...

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2015 International Conference on Fluid Power and Mechatronics

作者： Yunxiao Hao Jiahai Huang Wenyong Li Long Quan Bin Zhao Key Laboratory of Advanced Transducers and Intelligent Control System Ministry of Educationand Shanxi ProvinceTaiyuan University of Technology

Cartridge flow valves, widely applied in heavy machine and equipment, have the advantages of low leakage, large flow capacity, and simple structure. However, in the existence technologies, in order to reduce the influence of load variety on valve flow, a pressure differential compensator or a cartridge type flow sensor should be added to proportional throttle valve. This method reduces valve flow capacity and increases system throttling loss. In large flow occasion, flow only can be indirectly controlled by changing valve opening area for the limitation of the structure. So a low energy consumption, high controllable electro-hydraulic proportional valve which is structured by a hydraulic transistor(Valvistor) and a small displacement hydraulic pump driven by a servo motor is introduced. Based on the Valvistor valve flow amplification principle, main valve flow is controlled by pilot pump flow which is controlled by changing rotation speed without the influence of load variety. In the research, it's known from the analysis of the new principle valve steady flow characteristics that feedback throttle slot pre-opening will cause the decrease of the main valve flow as pressure drop increases. Soa method of pressure differential-pilot pump rotation speed compensation is put forward and it can obtain ideal flow characteristic. Then the dynamic mathematical model is established and the main valve stability criterion is derived. The influence of the valve parameters on main valve performance is analyzed and simulated. The results provide a new method forthe large flow electro-hydraulic proportional control system.

关键词： Valvistor Proportional flow control valve Pressure differential-rotation speed compensation Steady state characteristics

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