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91.
Beam smoothing by lens array with spectral dispersion 总被引:1,自引:0,他引:1
A scheme of combining technology of lens array (LA) and smoothing by spectral dispersion (SSD) is introduced to improve the irradiation uniformity in laser fusion based on the earlier works on LA. The feasibility of the scheme is also analyzed by numerical simulation. It shows that a focal pattern with flat-top and sharp-edge profile could be obtained, and the irradiation nonuniformity can fall down from 14% with only LA to 3% with both SSD and LA. And this smoothing scheme is depended less on the incidence comparing to other smoothing methods. The preliminary experiment has demonstrated its effectiveness. 相似文献
92.
93.
为了扩大复眼光学系统的接收光谱,研究了一种可见光、长波红外复眼光学系统.推导了双波段共焦面方程,建立了子眼系统与接收系统的匹配要求.子眼光学系统的工作波段为0.38~0.78μm和8~12μm,焦距为5mm,相对孔径为1∶3,视场为10°.两个波段的子眼系统成像位置均为2.92mm,相邻的两个中心光轴夹角为4.016°,共650个子眼,合并后的视场为90°.接收系统的焦距为4mm,视场为80°,相对孔径为1∶3.子眼系统和接收系统的图像质量良好,在-40~60℃的温度范围内无热差影响. 相似文献
95.
Sparse Bayesian learning (SBL) and particularly relevant vector machines (RVMs) have drawn much attention to improving the performance of existing machine learning models. The methodology depends on a parameterized prior that enforces models with weight sparsity, where only a few are non-zeros. Wideband mmWave massive multiple-input multiple-output (mMIMO) systems with lens antenna array (LAA), expect to play a key role in future fifth-generation (5G) wireless systems. To provide the beamforming gain required to overcome path loss, we consider a lens antenna array (LAA)-based beamspace mMIMO system. However, the spatial-wideband influence causes the beam squint effect to emerge, making the beamspace channel path components exhibit a unique frequency-dependent sparse structure, and thus nullifies the frequency domain common support assumption. In this paper, we first propose a channel estimation (CE) algorithm, namely a reduced-antenna selection progressive support-detection (RAS-PSD), for the wideband mmWave mMIMO-OFDM systems with LAA, which considers the beam squint effect. Secondly, by exploring Bayesian learning (BL), a Gaussian Process hyperparameter optimization-based CE (GP-HOCE) algorithm is proposed for the considered system, where both its own hyperparameter and the hyperparameters of its adjacent neighbors governs the sparsity of each coefficient. The simulation results show that the wideband beamspace channel coefficients can be estimated more efficiently than those of the existing state-of-the-art algorithms in terms of normalized mean square error (NMSE) of CE for wideband mmWave mMIMO-OFDM systems. 相似文献
96.
97.
Achromatic objectives are constructed by combining two or more lenses with properly chosen powers made of materials with different dispersions. We present a new approach that simplifies the design of multilens achromatic combinations as well as the choice of materials for them and show how this method can be applied to the design of a four-lens superachromatic combination. 相似文献
98.
In this paper, we proposed a strategy to find new local minima based on mutated damping factors and converged damping factor (conventional damping factor). In this proposed strategy, the converged damping factor is used to make the algorithm converge to a certain local minimum, and the mutated damping factors are used to make the trapped solution jump out of present convergence area. We study the behavior of the two kinds of factors in lens system optimization. The proposed strategy is successfully applied in lens system optimization. The result shows that the proposed strategy is reliable to make a further improvement especially when the solution is approaching target design. 相似文献
99.
Simulation and design of applied hollow-duct used for side-pumped cutting-edged of high power disk laser 总被引:1,自引:0,他引:1
H. Aminpour I. Mashaiekhy Asl J. Sabbaghzadeh S. Kazemi 《Optics Communications》2010,283(23):4727-4732
In this article a ray tracing method is used to design a specific hollow-duct whereby we show that it will be the best choice for pumping the gain medium that has inclined sides or cutting edges used for edge-pumped high power disk laser due to several advantages of the shape of this gain medium. This kind of hollow-duct which is called non-symmetric hollow-duct in this paper includes inclined output facet that compresses and homogenizes the emission of laser diode arrays which are coupled to the entrance-inclined surface of the gain medium. In this paper, the goals of designing this kind of hollow-duct are based on two important criteria: First, homogeneity of pump light distribution due to the beam concentration of laser diode bars according to the edge-pumped disk laser. Second, uniform distribution of pump light in non-symmetric hollow-ducts deducing uniform temperature distribution in the gain medium. 相似文献
100.
采用偶联法使抗人晶状体上皮细胞单克隆抗体与聚乳酸载 5_氟尿嘧啶毫微球偶联 ,制备出靶向人晶状体上皮细胞的免疫毫微球。采用扫描电镜和透射电镜观察微球形貌和结构 ,用动态光散射粒径分析仪测载药毫微球粒径。ELISA法检测偶联后的抗体活性 ,间接免疫荧光法检测该免疫毫微球与晶状体上皮细胞的特异性结合能力。结果显示载药毫微球表面光滑 ,平均粒径为191 0± 0 2 0 2nm ,其载药率为 8 2 %。免疫载药毫微球中的单克隆抗体HILE6保留达到原免疫活性84 %。该免疫载药毫微球能与晶状体上皮细胞特异性结合。该实验为特异性抑制晶状体上皮细胞增殖 ,预防白内障术后并发症_后囊混浊提供了重要的科学依据 相似文献