利用激光诱导击穿光谱技术定性分析矿石成分

利用激光诱导解析光谱方法,在小型化的实验装置上对铜矿石样品的元素成分进行了检测,定性分析了矿石的光谱特性并检测到包括Cu,Fe,Ca等在内的多种元素。结果表明,激光诱导解析光谱方法是一种潜在的快捷且有效的材料定性分析手段。     

三维激光扫描点位误差源分析

目前对三维激光扫描的分析主要停留在误差模型的建立上,没有对三维激光扫描仪的特点及其所受的误差进行分析,而三维激光扫描仪的系统误差和偶然误差都将会对整个误差模型的建立产生影响,点位误差源的准确分析是点位准确建立点位误差模型的基础。基于此,本文对三维激光扫描仪的点位误差源进行了分析,得到了不同误差源的误差模型,并给出了不同条件可能对激光扫描仪误差影响的大小。     

针对军校专业特点的激光课程教学改革探索

针对军队院校的专业特点,在"重基础,抓实验,贴装备"的教学思想指导下,在七个方面对激光课程进行改革,即:教员队伍建设、教材与课程内容、课堂教学、军校教学保障制度、实验教学、课外教学活动以及考核评价体系。改革取得一定成效,指出了存在的问题和努力方向。     

大型景观测绘中激光扫描的精度控制

激光扫描在复杂场景测绘中应用日益广泛,但是,点云配准精度较传统控制测量低。本文研究了将传统的控制测量应用到激光扫描测绘中的方法,可以减少因测站点增多带来的配准误差累计,从而提高点云配准精度,并以颐和园佛香阁三维建模的项目为例,对大型景观测绘中三维激光扫描精度控制的方法进行了研究及应用。     

周期混合信号和色关联噪声联合驱动下的单模激光随机共振

研究周期混合信号和色关联噪声联合驱动下的单模激光系统的随机共振现象,运用线性近似的方法得到输出信号光强的功率谱和信噪比.研究表明：信噪比都随泵噪声和量子噪声出现传统的随机共振现象;并讨论噪声的互关联时间和两信号的频率、振幅对信噪比的影响.     

基于FPGA的激光器功率控制系统设计

以FPGA芯片为控制核心结合相关的外围器件完成了激光器功率控制系统的设计。通过FPGA控制数字电位器DS1867实现了对激光器电源内部电阻的控制,改变激光器发射功率等级的目的。同时系统还实现了检测激光器所在环境的温度,及高温报警、定时控制等功能。     

Scanning electron microscope hypsometry as a tool for evaluating the impact of surface treatments: A case study on sub-fossil bone

Abstract

Plaster of Paris field jackets are commonly employed for lifting fragile archeological and paleontological material during excavation. When the plaster has been applied directly to the object surface its removal poses a severe risk of damage and loss. This study documents the development of an experimental method to test the suitability of various techniques for removing plaster of Paris from sub-fossil bone. The use of digital microscopic elevation models, already in use in other disciplines, was tested as a method for quantifying surface loss resulting from conservation treatments. The study concludes that citric acid is not suitable for use in close proximity to sub-fossil bone. Air abrasion and laser ablation proved extremely damaging, but ultrasonic cleaning caused no detectable damage. This study has relevance to the removal of plaster of Paris from other materials, such as carbonaceous statuary. The analytical technique itself has a far wider application and is recommended for evaluation of all surface treatments that have the potential to cause loss on a microscopic scale.     

Characteristics of Italian art restoration firms and factors influencing their adoption of laser technology

Given the limited number of studies on this topic, the aim of this study is to better understand the characteristics of art restoration firms in Italy, with particular reference to their use of innovative technologies such as laser technology. The paper is supported by a survey conducted in a sample of 100 companies. The factors that have led firms to adopt or resist the adoption of the laser were identified and analysed. The results show that the main determinants of laser adoption are collaborative activities between the firms and universities and specific requests made by public institutions to use this technology.

Effect of Ultrafine Particles on Flow Field and Transport Properties near the Interface Around a Moving Bubble

Laser Doppler Anemometer has been used to measure the flow field characteristics near the interface around a moving bubble in the presence of ultrafine particles. In order to model a moving bubble, the bubble was fixed into the counter-flow liquid by a metal mesh. Experimental materials are air and water, and the particles are complex oxidate powder. Experiments were carried out under the operating conditions: the liquid flow velocity u0 is 12.6cm/s, the equivalent diameter de is 0.6cm, the mass concentration of particle is 0.2%,the average particle diameter is about 10nm and the density is 2g/cm^3. The velocity profiles of beth frontal and tail-vortex areas were measured respectively. The experimental results show that the velocity fields are obviously changed in the existence of particles. In the frontal area of the bubble, beth tangential and normal velocities decrease due to the presence of particles, but in tail vortex area, the tangential velocities increase remarkably,and normal velocities rise gradually from the center towards the fringe in the opposite tendency to that of no partitles. The influences of flow field change in the presence of particles on gas-liquid mass transfer are analyzed and discussed.     

提高激光测距精度方法的研究

为了提高激光测距精度,采用理论分析的方法,提出了影响激光测距精度的主要因子,对现有的主要的测距方式脉冲和相位测距方式进行研究,并分析现有已经提出的测量精度方案,总结这些方案优缺点,这样有助于进一步提高激光测距的精度。