We report a high-peak-power, single-polarized master oscillator power amplification system employing polarization- maintaining Yb-doped rod-type photonic crystal fiber. The MOPA system comprises of a Q-switched microc...We report a high-peak-power, single-polarized master oscillator power amplification system employing polarization- maintaining Yb-doped rod-type photonic crystal fiber. The MOPA system comprises of a Q-switched microchip laser generating ~630ps pulses at 8.6 kHz repetition-rate and two amplification stages employing double cladding fiber and rod-type PCF respectively. The MOPA system obtains narrow spectral bandwidth, single-polarized pulses of 9W maximum output average power, corresponding to peak power of 1.7MW.展开更多
An integral terminal sliding mode controller is proposed in order to control chaos in a rod-type plasma torch system.In this method, a new sliding surface is defined based on a combination of the conventional sliding ...An integral terminal sliding mode controller is proposed in order to control chaos in a rod-type plasma torch system.In this method, a new sliding surface is defined based on a combination of the conventional sliding surface in terminal sliding mode control and a nonlinear function of the integral of the system states. It is assumed that the dynamics of a chaotic system are unknown and also the system is exposed to disturbance and unstructured uncertainty. To achieve a chattering-free and high-speed response for such an unknown system, an adaptive neuro-fuzzy inference system is utilized in the next step to approximate the unknown part of the nonlinear dynamics. Then, the proposed integral terminal sliding mode controller stabilizes the approximated system based on Lyapunov＇s stability theory. In addition, a Bee algorithm is used to select the coefficients of integral terminal sliding mode controller to improve the performance of the proposed method. Simulation results demonstrate the improvement in the response speed, chattering rejection, transient response,and robustness against uncertainties.展开更多
A mode-locked ytterbium-doped rod-type fiber laser with 85 ~tm core diameter is developed based on the nonlinear polarization evolution in an all-normal-dispersion ring cavity, in which a uniaxial birefringent plate i...A mode-locked ytterbium-doped rod-type fiber laser with 85 ~tm core diameter is developed based on the nonlinear polarization evolution in an all-normal-dispersion ring cavity, in which a uniaxial birefringent plate is used as the spectral filter. Average power up to 16 W is obtained at the repetition rate of 58 MHz, and the pulse duration is compressed to 182 fs with a grating-pair compressor. The output laser pulses show very good beam quality and power stability.展开更多
The conventional finite element model （FEM） of a rod-type ultrasonic motor is usually simplified by means of continuous composite structure. Because the actual contact characteristics between the parts of the ultras...The conventional finite element model （FEM） of a rod-type ultrasonic motor is usually simplified by means of continuous composite structure. Because the actual contact characteristics between the parts of the ultrasonic motor is ignored, there is bigger error between the calculated values and experimental results. Aiming at solving problem, a new modeling method of a rod-type ultrasonic motor is presented to obtain a high-accuracy FEM. The bolt pretension and the normal contact stiffness and friction coefficient of the contact surface of ultrasonic motor are all considered in this method, and the significant parameters of working mode of the motor are selected by the response surface method, and the goal of calculating the structural response rapidly is realized by building the response surface model to replace the FEM. The result of finite element model updating shows that the average error of modal frequencies of updated model drops to 0.21% from 1.20%. The accuracy of FEM is obviously improved, which indicates that the FEM updating based on response surface method is of great application value on the design for a rod-type ultrasonic motor.展开更多
We report the design and analysis of a rod-type photonic crystal fiber with Er-Yb co-doped for the high power 1.5-μm band amplifier.The fiber structure is designed to be the 120-μm extreme large core diameter,300-μ...We report the design and analysis of a rod-type photonic crystal fiber with Er-Yb co-doped for the high power 1.5-μm band amplifier.The fiber structure is designed to be the 120-μm extreme large core diameter,300-μm inner cladding diameter,and 1.5-mm outer cladding diameter that ensure the single mode output during high power amplification.Both the continuous wave(CW) and pulsed amplification characteristics are analyzed based on the exact modeling and simulation under the designed geometry.The 4-mJ pulse energy and 400-kW peak power are obtained in theory,so the 1.5-μm band amplifier that achieves milojoule level pulse energy meanwhile keeping single mode is firstly designed.展开更多
为提高高压交流罐式断路器与封闭金属气体绝缘开关设备(GIS)灭弧室组件的通用化水平,提出基于外置式电流互感器的集成化设计方案。通过将电流互感器独立外置于断路器壳体之外,实现了罐式断路器壳体与GIS灭弧室壳体结构的标准化统一,使...为提高高压交流罐式断路器与封闭金属气体绝缘开关设备(GIS)灭弧室组件的通用化水平,提出基于外置式电流互感器的集成化设计方案。通过将电流互感器独立外置于断路器壳体之外,实现了罐式断路器壳体与GIS灭弧室壳体结构的标准化统一,使两者具备相同的法兰接口与密封结构。针对配套的导电杆组件,采用三维电磁场仿真软件建立关键部件的精细化模型,重点分析雷电冲击电压(1050 k V)工况下的电场分布特性,从而对原始方案中电场强度不均匀的地方进行改进,并通过仿真分析对导电杆尺寸优化设计,根据优化设计结果进行相关试验,验证了该设计的准确性。展开更多
文摘We report a high-peak-power, single-polarized master oscillator power amplification system employing polarization- maintaining Yb-doped rod-type photonic crystal fiber. The MOPA system comprises of a Q-switched microchip laser generating ~630ps pulses at 8.6 kHz repetition-rate and two amplification stages employing double cladding fiber and rod-type PCF respectively. The MOPA system obtains narrow spectral bandwidth, single-polarized pulses of 9W maximum output average power, corresponding to peak power of 1.7MW.
文摘An integral terminal sliding mode controller is proposed in order to control chaos in a rod-type plasma torch system.In this method, a new sliding surface is defined based on a combination of the conventional sliding surface in terminal sliding mode control and a nonlinear function of the integral of the system states. It is assumed that the dynamics of a chaotic system are unknown and also the system is exposed to disturbance and unstructured uncertainty. To achieve a chattering-free and high-speed response for such an unknown system, an adaptive neuro-fuzzy inference system is utilized in the next step to approximate the unknown part of the nonlinear dynamics. Then, the proposed integral terminal sliding mode controller stabilizes the approximated system based on Lyapunov＇s stability theory. In addition, a Bee algorithm is used to select the coefficients of integral terminal sliding mode controller to improve the performance of the proposed method. Simulation results demonstrate the improvement in the response speed, chattering rejection, transient response,and robustness against uncertainties.
基金supported by the National Key Technology R&D Program of the Ministry of Science and Technology,China(Grant No.2012BAC23B03)the National Basic Research Program of China(Grant No.2013CB922401)the National Natural Science Foundation of China(Grant No.11474002)
文摘A mode-locked ytterbium-doped rod-type fiber laser with 85 ~tm core diameter is developed based on the nonlinear polarization evolution in an all-normal-dispersion ring cavity, in which a uniaxial birefringent plate is used as the spectral filter. Average power up to 16 W is obtained at the repetition rate of 58 MHz, and the pulse duration is compressed to 182 fs with a grating-pair compressor. The output laser pulses show very good beam quality and power stability.
基金supported by Foundation of the State Key Laboratory of Mechanics and Control of Mechanical Structures(MCMS-0314G02)Open Foundation of Engineering Mechanics Analysis of Key Laboratory of Jiangsu Province+1 种基金Foundation of Basic and Advanced Technology Research of Henan Province(152300410040)Foundation of Science and Technology Development of Zhengzhou(131PPTGG409-1)
文摘The conventional finite element model （FEM） of a rod-type ultrasonic motor is usually simplified by means of continuous composite structure. Because the actual contact characteristics between the parts of the ultrasonic motor is ignored, there is bigger error between the calculated values and experimental results. Aiming at solving problem, a new modeling method of a rod-type ultrasonic motor is presented to obtain a high-accuracy FEM. The bolt pretension and the normal contact stiffness and friction coefficient of the contact surface of ultrasonic motor are all considered in this method, and the significant parameters of working mode of the motor are selected by the response surface method, and the goal of calculating the structural response rapidly is realized by building the response surface model to replace the FEM. The result of finite element model updating shows that the average error of modal frequencies of updated model drops to 0.21% from 1.20%. The accuracy of FEM is obviously improved, which indicates that the FEM updating based on response surface method is of great application value on the design for a rod-type ultrasonic motor.
文摘We report the design and analysis of a rod-type photonic crystal fiber with Er-Yb co-doped for the high power 1.5-μm band amplifier.The fiber structure is designed to be the 120-μm extreme large core diameter,300-μm inner cladding diameter,and 1.5-mm outer cladding diameter that ensure the single mode output during high power amplification.Both the continuous wave(CW) and pulsed amplification characteristics are analyzed based on the exact modeling and simulation under the designed geometry.The 4-mJ pulse energy and 400-kW peak power are obtained in theory,so the 1.5-μm band amplifier that achieves milojoule level pulse energy meanwhile keeping single mode is firstly designed.
文摘为提高高压交流罐式断路器与封闭金属气体绝缘开关设备(GIS)灭弧室组件的通用化水平,提出基于外置式电流互感器的集成化设计方案。通过将电流互感器独立外置于断路器壳体之外,实现了罐式断路器壳体与GIS灭弧室壳体结构的标准化统一,使两者具备相同的法兰接口与密封结构。针对配套的导电杆组件,采用三维电磁场仿真软件建立关键部件的精细化模型,重点分析雷电冲击电压(1050 k V)工况下的电场分布特性,从而对原始方案中电场强度不均匀的地方进行改进,并通过仿真分析对导电杆尺寸优化设计,根据优化设计结果进行相关试验,验证了该设计的准确性。
