激光雷达距离欺骗干扰技术研究

文章主要介绍激光雷达测距的原理,激光测距机的组成及各部分的功能,根据其原理,介绍一种常用的距离欺骗的方法-数字储频技术,阐述其距离假目标欺骗的原理,对其工作过程进行仿真。研究表明,采用数字储频技术能够有效的进行欺骗,这种技术既可以用于掩护空防,又可以用于干扰敌方并诱敌开机,暴露其真实的兵力部署,因此具有相当大的军事意义。     

研究生《激光等离子体相互作用原理》专业课程创新教学模式探索

介绍了国内激光等离子体相互作用课程的教学情况、教材使用情况,国防科学技术大学理学院在该课程的教学中所进行的创新性教学模式探索实践和所取得的成效。最后总结了教学改革和人才培养的经验,对其它研究生课程建设具有一定的参考价值。     

基于P-范分布下的三维激光点位误差分布检验

目前,在对三维激光点位误差模型进行推导的过程中,都是假设三维激光点位误差是服从正态分布的,而由于三维激光点位误差源与传统测量仪器中的误差源不同,同时外界环境对激光点位误差的影响也不相同,因此,不能直接断定点位误差服从正态分布,需要对其理论分析及数据统计分析验证。针对三维激光点位误差分布状况,本文对激光点位误差模型进行了推导,并通过大量数据统计分析验证了激光点位误差服从的分布状况。     

Design and Realization of InP/AlGaInAs Multiple Quantum Well Ring Laser

Using beam propagation method(BPM), key optical design parameters of InP/AlGaInAs multiple quantum well(MQW) ring laser were numerically analyzed. The influences of waveguide dimensions, curvature radius and gap size on the coupling efficiency were discussed. An InP/AlGaInAs MQW ring laser with radius of 350 μm was designed and realized. The experimental results show that the designed device, lasing at 1 563.2 nm with side mode suppression ratio higher than 20 dB, exhibited unidirectional bistability between the clockwise and counterclockwise modes.     

基于曲线匹配的星载激光测高仪无场在轨几何定标方法

星载激光测高技术的快速发展急需有效的在轨几何定标方法来校正测高数据中的系统误差。探索一种基于曲线匹配的测高仪无场在轨几何定标方法。该方法利用激光足印高程曲线与DEM进行匹配获得激光足印控制点进而实现定标参数求解,无需到野外布设探测器定标场地。采用资源三号02星激光测高数据进行定标方法验证,并对定标结果进行精度评估。实验表明,经本文的定标方法校正后的测高数据的精度得到显著提升,验证了本方法的有效性。     

神光Ⅱ高功率激光实验装置研制

惯性约束聚变(ICF)研究的长远目标,是实现可控核聚变,为人类提供理想的能源。神光Ⅱ高功率激光装置是由中国科学院、中国工程物理研究院、国家“863”计划支持的大科学工程项目。该装置是目前我国规模最大、国际上为数不多的高性能高功率固体激光装置,是我国中近期惯性约束聚变重要实验平台。     

自组织型光纤激光器阵列的理论研究

主要对自组织型光纤激光器阵列技术进行了理论研究。重点利用耦合迭代法对自组织型相干光纤激光器阵列进行了分析,并给出了电场和增益系数的耦合迭代方程。对进一步对自组织型光纤激光器进行数学建模和理论分析提供了理论基础。     

计算机测控光的偏振教学实验系统

针对传统偏振光与波片实验需人工调节偏振片和波片转角并记录数据,过程繁琐、数据量大、耗时过长的问题,开发出计算机测控的教学实验系统。以半导体固体激光器为光源,PC机通过USB接口和控制器驱动步进电机,带动中心有透光孔的精密电控旋转台按设定步距角转动。激光束与转台中心同轴,偏振片或波片同心安装在旋转台上同步旋转,透射光经过检偏器,由数字式光功率计检测通过各元件后光强的变化;信号经另一USB接口传输至PC机。计算机控制偏振片或波片旋转,同时自动采集对应转角的透射光强值并存储。实验结束后检测结果可通过数据文件导出,由学生在课后自行处理。新教学实验系统可完成1/4和1/2波片实验,验证马吕斯定律,能大幅度节省实验时间并提高精度。     

基于磁光传感器的焊缝检测装置的研制

针于激光焊接所要求的紧密焊缝,构建以磁光传感器为核心的焊缝检测装置,该装置能检测出反映焊缝特征的磁光图像.通过分析磁光图像的特点,确定磁光图像中过渡带的中心为焊缝中心.最后,通过中值滤波,获得比较清晰的磁光图像,并把该图像进行灰度化处理,获得沿焊缝两侧的灰度变化图,通过分析灰度变化图,能获得焊缝的测量中心,这为利用磁光图像进行微焊缝跟踪的激光焊接确定了可能性.     

A re-united pair: The conservation,technical study,and ethical decisions involved in exhibiting two terracotta orante statues from Canosa

The collection of the Worcester Art Museum includes two rare Magna Graecia terracotta funerary statues from Canosa, Italy dating to the third century BCE. Each depicts a female figure in prayer or lament known as an orante. The orantes were purchased by the museum in 1927, but shortly thereafter were separated. One was left in storage for nearly seven decades and the other was sold, and ultimately entered a private collection halfway around the world. The orantes were recently reunited under serendipitous circumstances and, after more than 80 years, will finally be placed on display at the Museum. As part of a comprehensive treatment, a technical study was carried out to identify the materials and methods used in their manufacture and in previous restoration campaigns. Materials were characterized by cross-section analysis, spot tests, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), neutron activation analysis (NAA), thermogravimetric analysis (TGA), thermoluminescence (TL) dating, and reflectance transformation imaging (RTI). The analytical findings helped inform the conservation treatments, which included structural work, surface cleaning using a Nd:YAG laser, and esthetic reintegration.