排序方式: 共有39条查询结果,搜索用时 250 毫秒
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A new type of optical amplifier based on co-doping erbium in thulium doped fiber is proposed to realize S C band gain by dual-wavelength (800 1410 nm) pumping scheme which is obtainable from laser diode. A novel model is established for the co-doped fiber considering the Er3 to Tm3 energy transfer process. Using appropriate fiber parameters and energy transfer parameters, the coupled rate equations are analyzed and solved; the concentrations of Er3 and Tm3 and fiber length were optimized to get more uniform gain. The results predicted that the S C band gain can be achieved at the same time by co-doping erbium in thulium doped fluoride fiber. 相似文献
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基于对离轴反射变焦距光学系统进行计算机辅助装调研究, 需要检测离轴反射变焦距系统各个视场的波像差, 除零度视场外, 获得包括其他视场的波像差有助于提高计算机辅助装调的准确性, 但是目前已有的波像差检测方法往往只能获得系统零度视场的波像差. 本文针对这个难题提出了一种检测离轴反射变焦距光学系统各个视场波像差的方法, 并应用于离轴三反变焦距光学系统的各视场波像差仿真检测. 该方法在传统自准直干涉法的基础上进行改进, 关键在于采用变形镜代替扫描的平面镜, 并采用夏克-哈特曼波前传感器代替干涉仪, 配合精确标定的激光器光源阵列, 可以实现对离轴三反变焦距光学系统的多视场波像差同时检测. 由理论分析和仿真模拟得出, 该系统在视场(0°, 3°), (0°, 4.2°), (0°, 5.5°), (0°, 7°), (0°, 9.8°), (0°, 14°)处经过变形镜补偿后的剩余波像差的RMS值分别为0.00039λ, 0.00075λ, 0.0024λ, 0.00017λ, 0.00053λ, 0.0057λ, 分析仿真结果表明此检测方案是可行的, 且适用于离轴反射变焦距系统的计算机辅助装调技术的研究. 相似文献
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基于能量准则的板振动控制的LQR法 总被引:3,自引:1,他引:3
针对压电层合结构振动的主动控制问题,为了优化控制效果,本文基于现代控制理论提出了选用结构振动能量和控制信号能量作为控制目标函数的LQR法。首先,按能量准则推导了控制目标函数中权系数矩阵(Q矩阵和R矩阵)的理论计算公式,为权系数矩阵的选取提供了一定的理论依据。然后,运用该算法,分析了压电层合板受到初始位移激励和冲击载荷作用下的控制过程,用Matlab进行系统仿真,得到了板中心点的位移和控制电压大小随时间变化的曲线。数值模拟的结果表明,该方法能达到更有效控制结构振动和减小控制能量消耗的目的,与一般的LQR控制方法相比,能满足系统多方面的设计要求且控制效果更优,从而验证了该LQR方法运用到结构振动主动控制中的可行性。 相似文献
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弹性板振动的多模态主动控制 总被引:2,自引:0,他引:2
采用多对压电片对板振动的多阶模态进行主动控制。为了改善结构振动控制的效果,本文对选用结构振动能量和控制信号能量作为控制目标函数的LQR控制算法作了初步研究。首先,按能量准则推导了控制目标函数中权系数矩阵(Q矩阵和R矩阵)的理论计算公式,为权系数矩阵的选取提供了一定的理论依据。然后,运用该算法,在研究了单对压电片进行振动主动控制的基础上.本文深入分析了压电层合板振动的多阶模态控制的问题,用Matlab进行系统仿真,得到了压电层合板受到初始位移激励下板中心点的位移和控制电压大小随时间变化的曲线。数值模拟的结果表明,该方法能达到更有效控制结构振动和减小控制能量消耗的目的.进一步验证了该方法能达到有效控制结构振动和减小控制能量消耗的目的。 相似文献
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A conformal optical system refers to the one whose first optical surface conforms to both aerodynamic and imaging requirements. Appropriate correction is required because a conformal dome induces significant aberrations. This paper intends to explain that an effective solution to the easy-fabrication conic surface corrector compensates aberrations induced by a coaxial aspheric dome. A conformal optical system with an ellipsoid MgF2 conformal dome, which has a fineness ratio of 2.0, is designed as an example. The field of regard angle is pm 30 degrees with a pm 2 degree instantaneous field of view. The system's ultimate value of modulation transfer function is close to the diffraction limit, which indicates that the performance of the conic conformal optical system with a fixed conic corrector meets the imaging requirements. 相似文献
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We present a model of passively Q-switched Raman lasers by utilizing the rate equations. The intracavity fun-damental photon density, Raman photon density and the initial population-inversion density of the gain medium are assumed to be of Gaussian spatial distributions. These rate equations are normalized by introducing some synthetic parameters and solved numerically, and a group of general curves are generated. Prom these curves we can understand the dependence of the Raman laser pulse characteristics on the parameters about the pumping, the gain medium, the Raman medium and the resonator. An illustrative calculation for a passively Q-switched Nd^3+:GdVO4 self-Raman laser is presented to demonstrate the usage of the curves and related formulas.[第一段] 相似文献