论文部分内容阅读
激光技术2011年 目录
【出 处】
:
激光技术
【发表日期】
:
2011年35期
其他文献
Localized wavefront aberrations would introduce artifacts in biomedical imaging, which, however, are often neglected, as their compensations are at the cost of the field-of-view. Here, we show rarely reported local artifacts in two-photon imaging of dendr
采用CO2激光器对珠光体基体的球墨铸铁表面进行了点状合金化处理。设计了激光合金化点的分布方案,研究了强化层的组织和性能,对激光处理后的试样进行了热疲劳实验。结果表明,预置TH-2A型C-Si-B-RE合金化涂层,选择适当的激光辐照参数,可以获得表面光洁、硬度高、无裂纹的合金化层。热疲劳实验的循环温度为700 ℃至25 ℃,加热90 s,冷却10 s,共循环90次。实验发现,激光合金化点及其热影响区(HAZ)以外表面区域的热疲劳裂纹萌生主要与石墨球的存在及其圆整度有关,基体中裂纹的扩展在点状合金化区周围受到
可调谐液晶光子晶体是通过加电场、光场或改变液晶温度来改变液晶指向矢的方向,进而改变液晶折射率达到控制光子带隙的目的。运用平面波展开法(PWM)对圆柱、方柱及正六边柱构造的二维可调谐液晶三角格子光子晶体的禁带进行仿真模拟,讨论了基底材料分别为Ge和Si情况下,柱子形状、旋转角度和填充比的变化对二维苯乙炔型液晶光子带隙的影响。发现均无完全光子禁带出现,而通过改变液晶折射率可得到大调谐范围的TE偏振光。该结构参数可为制造大调谐范围的场敏偏光片提供理论上的指导、同时也为波导光开关、可调谐滤波器和光衰减器的研制提供
Resonant effect is found in femtosecond laser ablating Pr–Nd glass. When processed with resonant wavelength of 807 nm, resonant ablation efficiency (RAE) with a single pulse can be improved by 45.22%. Furthermore, RAE closely relates to laser intensity. F
A novel unsupervised ship detection and extraction method is proposed. A combination model based on visual saliency is constructed for searching the ship target regions and suppressing the false alarms. The salient target regions are extracted and marked
期刊
A novel orthogonal modulation format of D8PSK/ASK with differential bi-phase encoding and its applic
The principle of a novel orthogonal modulation format of differential 8-level phase-shift keying amplitude-shift keying (D8PSK/ASK) with differential bi-phase encoding (DBC) is introduced. Based on it, an optical labeling scheme, in which the payload is 1
期刊
Different from previous focusing on subwavelength imaging in the near field, we outline another potentially useful application of the self-collimating photonic crystal -- low-pass spatial filtering. A two-dimensional square-lattice photonic crystal is tak
根据湍流大气中激光对数强度的最低几阶中心矩建立了一种最大似然概率分布模型, 该模型可以方便和准确地描述实际概率分布。 根据实验结果分析了激光对数强度的概率分布的偏斜度和陡峭度的特征。 发现在弱起伏条件下, 对数强度的概率分布一般接近于正态分布, 当偏离正态分布时, 概率密度分布的偏斜度总是为负, 陡峭度总是为正。
在利用空间调制傅里叶变换光谱仪对远距离目标进行光谱遥测时,大气湍流扰动引起的入射光场的波前畸变会影响干涉图像和复原光谱的质量。根据大气湍流扰动对光场的相位调制作用,建立了大气湍流的随机相位模型与光场在大气中的分步传输模型,并对大气湍流扰动作用下的干涉图像与复原光谱进行了数值计算,结果显示:大气湍流会导致干涉图像的背景产生低频的强度起伏,并致使复原光谱在低频区域出现伴频噪声。采用统计实验的方法对归一化光谱误差与望远系统入瞳放大率、大气相干长度之间的关系进行统计分析。结果表明:归一化光谱误差的统计均值与望远系