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We investigate the nonvolatile holographic storage characteristics of near-stoichiometric LiNbO3:Fe:Mn crystals with different Li2O contents. Experimental results indicate that the optimal value of Li2O content is about 49.6 mol%. Nonvolatile sensitivity
We report on the first electrically pumped continuous-wave (CW) InAs/GaAs quantum dot (QD) laser grown on Si with a GaInP upper cladding layer. A QD laser structure with a
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对空基光电对抗平台可见光变焦镜头进行了光机结构设计以及被动消热差设计,依据-20~50 ℃的工作温度指标要求,对变焦镜头进行光机热集成分析。用Patran软件对镜头加载温度应力,计算光机结构的热弹性变形,用Nastran软件解算热变形后各光学元件镜面节点的刚体位移。用Sigfit光机接口软件分析变形后每个透镜表面的Zernike系数,将结果导入Zemax中,预判镜片面型变化以及刚体位移变化对调制传递函数(MTF)与波前差的影响。实验结果表明,在-20~50 ℃的温度载荷下,后固定组的最大轴向位移可达6.1
The Ho3 /Pr3 co-doped NaYF4single crystals with various Pr3 concentrations and constant Ho3 molar percentage of ~1% were grown by an improved Bridgman method. Compared with the Ho3 single-d
Germanium doping in silica can be used as a method for nonlinearity enhancement. Properties of the enhanced nonlinearity in photonic crystal fiber (PCF) with a GeO2-doped core are investigated theoretically by using all-vector finite element method. Numer
利用激光微束穿刺法将苏云金芽孢杆菌的毒蛋白(δ-endotoxin)基因导入了油菜,经聚合酶催化链式反应(PCR)和PCRSouthern杂交证明抗虫基因已导入油菜基因组中并能在T1代得到遗传。对转基因植株进行了抗虫性测试,结果表明某些植株具有较好的抗虫性,并且这种抗虫性在T1代仍能保持。实验结果表明抗虫基因已整合进油菜基因组并得到了稳定的遗传。
The generation of high-peak-power, few-cycle mid-infrared (MIR) pulses using coherent beam combination and nonlinear pulse compression techniques simultaneously is demonstrated. The two pulses, with identical pulse energy of 2.8 mJ and pulse duration of 1
为解决在复杂变光照环境下车道标识线的辨识问题,实现全天候环境的车道偏离预警,提出了一种新的车道标识线辨识算法。将基于OTSU算法的自适应图像分割技术用于在不同光照环境下车道标识线的划分,对图像的全局阈值和局部阈值进行加权处理得到自适应阈值,采用45°与135°梯度方向的Sobel算子提取车道边缘信息,通过改进Hough变换方法完成车道标识线的辨识过程。对不同光照环境下的道路图像进行对比实验,结果表
介绍了一种利用强脉冲激光诱导产生的冲击波压力来进行金属表面改性的新技术——受控激光喷丸强化技术,可以大幅度提高金属材料的疲劳寿命和抗应力腐蚀能力,但疲劳寿命和抗应力腐蚀能力并不总随着喷丸强度的提高而线性增加。最佳的疲劳寿命和抗应力腐蚀能力常出现在特定的残余压应力水平和分布下,也即取决于喷丸参数的最佳组合。由于激光喷丸中工艺参数对喷丸后工件表层的残余应力场有决定性的影响,如何依据已给的疲劳寿命和抗应力腐蚀能力来合理确定喷丸强化的工艺参数成为目前主要的研究方向。受控激光喷丸的机理与残余应力的形成过程密切相关。