搜索结果: 16-30 共查到“知识库 光电子学与激光技术”相关记录1642条 . 查询时间(3.975 秒)
封闭空腔回转薄壁件的激光熔覆成形
激光熔覆 光内送粉 斜定向分层 封闭回转件
2018/1/25
封闭空腔结构具有大倾角的特征，如采用传统的水平分层法堆积，大倾角部分的熔池易产生塌陷，使成形无法进行；采用变角度法向分层堆积大倾角封闭区域时，存在激光与已成形部分的干涉问题。文中基于中空激光光内送粉技术进行了空间堆积封闭半球壳体的研究。将封闭半球壳体划分为变角度法向成形区域和斜定向成形区域，前者采用变角度法向分层方法进行堆积，以消除阶梯效应；后者采用斜定向错位分层方法进行堆积，避免了封闭区堆积时激...
激光烧蚀驱动是移除厘米级空间碎片非常有前景的技术，但空间碎片不规则的几何形状对激光烧蚀产生的驱动效果有十分复杂的影响，是目前研究的难点和热点之一。从激光烧蚀驱动目标冲量耦合规律出发，基于通过目标表面顶点的三角化三维重构，提出了一种可以精确计算激光辐照外形不规则目标所产生冲量大小及方向的方法。以立方体、球体和圆柱体3个典型的几何外形规则的目标为对象，验证了该方法的计算精度。利用该方法研究了激光辐照几...
基于高功率光纤激光器的清漆剥离实验研究
光纤脉冲激光器 MOPA 清漆剥离
2017/12/31
研制了高功率光纤调Q脉冲激光器，搭建了基于高功率光纤脉冲激光器的激光剥离实验系统，并将其应用于高铁车厢表面清漆层的激光剥离试验。高功率光纤脉冲激光器采用MOPA结构，通过主放大，实现了中心波长为1 064.52 nm，重复频率为100 kHz、脉冲宽度为138.4 ns、平均功率为101.4 W的脉冲激光输出，其中主放大光光转换效率达到80%。利用该激光器对高铁车厢表面清漆层进行了剥离，研究了能量...
外腔振荡式激光光子推进的推力放大特性仿真研究
激光光子推进 推力放大 COMSOL 微推力
2017/12/31
激光光子推进是利用激光产生的连续光子流在两面高反镜构成的振荡腔内往复振荡，通过光子与推力器多次动量交换循环利用光子流能量完成推力放大的一种全新的推进概念。文中分析了Gray和Edwards等人对于外腔振荡技术已进行的实验研究和结果；阐述了推力产生机理并推导了推力计算方程；建立了推力器模型；最后，利用COMSOL有限元分析软件对振荡腔内的光子流进行准确追迹，研究振荡腔构型参数（腔镜距离、曲率、直径、...
沙尘气溶胶粒子数量浓度计算及激光传输特性
数量浓度 质量浓度 传输 Monte Carlo方法
2017/12/31
沙尘气溶胶粒子的数量浓度很难直接测量，但又是影响激光传输特性最主要的因素之一。基于沙尘气溶胶粒子的质量浓度，利用其粒径分布特性推导出了粒子数量浓度的计算公式。利用Mie理论和Monte Carlo方法研究了激光在沙尘条件下的传输特性，分析了激光的传输衰减和透射率随波长和质量浓度的变化关系，给出了能见度随粒子质量浓度的变化曲线，并对两种方法的计算结果进行了比较。结果表明：在选择的几个波长中，激光在波...
随着激光干扰技术在红外成像制导武器领域的深入应用，激光干扰效能和抗激光干扰技术的研究也日益被重视，它们与激光干扰模型研究也密切相关。为了构建高置信度激光干扰耀斑模型，首先分析了激光干扰的物理模型与全链路传输特性，在此基础上建立激光干扰耀斑理论模型，同时又分析了不同波长激光在大气传输中的影响规律、不同发散角随距离变化的辐照度变化规律，最后通过数字模拟仿真的结果与激光照射红外相机实验进行对比，验证了激...
搭建了一套金属厚度测量系统，其中激光器用于激励产生超声波，激光干涉仪和压电换能器分别用于接收激励产生的超声纵波信号。根据激光超声产生的机理，建立了纵波声束指向性模型，确定了影响声束指向性的因素，并分别给出了激光垂直入射下干涉仪和压电换能器接收超声波幅值的公式；实验研究了离焦量对测厚信号的影响，发现等量激光脉冲激励下，随着离焦量的增加会出现先增大后减小最后消失的现象，与理论计算结果相吻合，证实了该研...
EVOLVING TECHNIQUES OF DOCUMENTATION OF A WORLD HERITAGE SITE IN LAHORE
3D - laser scanning EDM documentation world heritage site cultural heritage photo rectification conservation urban heritage Lahore Fort
2017/8/18
Lahore is an ancient, culturally rich city amidst which are embedded two world heritage sites. The state of historic preservation in the country is impoverished with a dearth of training and poor docu...
USE OF 3D TECHNOLOGIES WITHIN THE CONSERVATION OF THE ANCIENT WINDOWS OF THE BASILICA OF S. SABINA IN ROME. CONSTRUCTION OF EXHIBITION STANDS IN CARBON COMPOSITE ON A MILLED STRUCTURE
3-D milling 3-D modeling exhibition stands carbon fiber composite laser cleaning fragmented artifact counterforms restoration
2017/5/20
Rare and precious window elements from the Paleochristian Basilica of Saint Sabina in Rome, made of plaster gypsum with translucent selenite used as glass for light transmission, were discovered by An...
SURVEY OF THE PAGODA TIMBER ROOF IN DERNEBURG CASTLE
Timber structures Structural analysis Roof CAD representation Laser scanner survey
2017/5/20
The work analyses the historical roof of Derneburg Castle, in the municipality of Holle, Hildesheim’s district, Lower Saxony, Germany. The roof is assembled according to Laves Balken’s system (Laves b...
3D SURVEY TECHNIQUES FOR THE ARCHITECTUTAL RESTORATION: THE CASE OF ST. AGATA IN PISA
Architectural survey laser scanning Structure from Motion restoration Pisa St. Agata
2017/5/20
The historical architectural heritage may be considered as the product of a complex system of interaction between several factors - cultural, socio-economic, technical, aesthetic etc. The restoration ...
THE TEMPIO DELLA CONSOLAZIONE IN TODI: INTEGRATED GEOMATIC TECHNIQUES FOR A MONUMENT DESCRIPTION INCLUDING STRUCTURAL DAMAGE EVOLUTION IN TIME
Historical Buildings Instability and restoration of the structures Differential Subsidence Knowledge Diagnostics Laser Scanning 3D Modeling
2017/5/20
The Tempio della Consolazione in Todi (16th cent.) has always been one of the most significant symbols of the Umbrian landscape. Since the first times after its completion (1606) the structure has exh...
LASER SCANNING AND MODELLING OF BARELY VISIBLE FEATURES: THE SURVEY OF THE GROTTO OF THE ANIMALS AT THE VILLA OF CASTELLO (FLORENCE)
Mannerist gardens Artificial grottoes Ancient hydraulic systems Laser scanner Mesh modelling
2017/5/20
The deep fusion of natural and artificial elements typical of Italian Renaissance gardens is particularly evident in the park of Villa di Castello and in the Grotto of the Animals, also called Grotto ...
THE COMPLEX POINT CLOUD FOR THE KNOWLEDGE OF THE ARCHITECTURAL HERITAGE. SOME EXPERIENCES
Laser Scanner EXPERIENCES
2017/5/20
The present paper aims to present a series of experiences and experimentations that a group of PhD from the University of Naples Federico II conducted over the past decade. This work has concerned the...
LASER-SCANNER SURVEY OF STRUCTURAL DISORDERS: AN INSTRUMENT TO INSPECT THE HISTORY OF PARMA CATHEDRAL’S CENTRAL NAVE
Parma Cathedral Laser Scanner Structural Disorders Historical Monitoring Structural Analysis
2017/5/20
This paper presents the use of laser scanner derived data for the study of the structural disorders in the central nave of the Parma Cathedral. An accurate three-dimensional model of the entire nave w...