LX1500激光引伸仪测量示值不确定度分析及评定

简单介绍了LX1500激光引伸仪的测试原理,详细介绍了该激光引伸仪的校准方法,分析了校准误差和测量不确定度,最后介绍了一个应用实例.     

激光近视治疗仪的研制及其临床效果

根据我国传统针灸刺激穴位,恢复睫状肌调节功能的原理,我们于87年研制6台激光近视治疗仪。通过在大学、中学、小学等四个单位进行的临床试验表明,只要接受治疗,视力均有不同程度的提高。     

研究性教学在激光原理课程的应用

为提高激光原理课程的教学效果,通过阐述研究性教学在激光原理课程中的应用手段,探讨了从激光原理理论到激光实际应用中如何提高学生的主观能动性,培养学生的创新能力。研究性教学能够提高学生学习激光原理的兴趣性、积极性和主动性,增强学生的个体独立性和团队合作意识。     

薄板激光焊接夹具结构设计

针对厚度为0.1mm以下的薄板在激光焊接过程中易变形及发生错位的特点,设计了一套专用夹具,对薄板焊缝进行精确定位、对位和夹紧,防止焊接后薄板错位及有效减少拼接缝隙对焊缝的影响。     

Laser-based manufacturing concepts for efficient production of tailor welded sheet metals

Laser welding is an established manufacturing technology for a large variety of automotive applications due to its attractive properties such as low heat input, high precision and fast welding speed. Especially when welding high strength steels, which are dominantly used in today＇s car body construction, the low heat input by laser welding bears significant advantages with regard to the properties of the weld seam. The exploitation of the full application potential of laser welding in mass production requires an appropriate manufacturing concept and corresponding auxiliary technologies. The present paper demonstrates the integration of laser welding into the surrounding manu- facturing concepts by a modular setup with different levels of automation. This approach offers flexible solutions for individual needs thereby optimizing investment cost, labor cost and productivity. Recently available laser sources enable exceptionally high welding speed on thin gauged sheet metals but require efficient material handling con- cepts to utilize the full speed potential. Industrial concepts are presented offering efficient material handling and high process robustness for mass production welding.     

Dynamic identification of historic masonry towers through an expeditious and no-contact approach: Application to the “Torre del Mangia” in Siena (Italy)

The paper presents a synergic and multidisciplinary approach where laser scanner survey, radar interferometric monitoring and finite element (FE) numerical modelling are used for expeditious and no-contact dynamic identification of monumental masonry towers. The methodology is applied to a real case of great historical interest: the “Torre del Mangia” (Mangia's tower) in Siena (Italy). The tower geometry was acquired through Terrestrial Laser Scanning (TLS) techniques. The tower oscillations were detected using an interferometric radar in “Piazza del Campo”, the square facing the Mangia's Tower, along three alignments, and movement of the structure at several heights were recorded. A FE model, built on the basis of the geometry acquired through the TLS, was used to interpret and verify the physical meaning of the experimental results. Through the discussion of the case study, the paper shows that the proposed approach can be considered as an effective and expeditious method for assessing the dynamic behavior of monumental buildings (and to plan interventions) on territorial scale.     

Middle-ultraviolet laser cleaning of particulates from sized ground wood cellulose and pure cellulose paper

Ground wood cellulose paper exhibits a practicable cleaning laser fluence window during middle-UV radiation processing. In this case, a minimum dose volume density should be applied. However, cleaning of bleached cellulose paper is accompanied by strong yellowing and destruction. The presence of charcoal graphite particulates shows substantial influence on the yellowing with increasing coverage.     

Stabilization of an abutment under a rigidly fixed bridge by holographical-speckle interferometry

Objective： There are no detailed reports of three-dimensional measurement of abutment teeth in mastication, because it is knotty to observe the rotation in chewing directly, and inexact to estimate indirectly. This work studies the three-dimensional stability of rigidly fixed bridge under the stresses of distributed loads and concentrated loads by optical method that gives the tip angle and rotation angle calculated directly based on measurement data. Methods： The specimen, taken from a 25-year-old male, was a left mandible without the second premolars and the first molars. As abutments, first premolar and second molar have complete periodontium. The specimen was soaked in formaldehyde solution. The bridge was fixed between two abutment teeth （first premolars and second molars）, and the mandible was cemented in a steel box. The load was increased from 0 kg to 23 kg. Laser holographic technique was used to measure the three-dimensional bit shift of the dens, both buccolingual bit shift and mesiodistal bit shift, and determine tip angle and rotation angle. Results： The effects of stress distribution on the rigidly fixed bridge were evaluated, and stabilization of the bridge under the stresses of distributed loads and concentrated loads, respectively, were analyzed. The results showed that the tips of two abutments were very similar, and no distinct difference was observed between the distributed load and the concentrated load. However, the maximum rotation angle for the distributed load was two to four times as large as that for the concentrated load. In the experiment, the tip angle of the abutment teeth was no more than 0.65 degree, and the rotation angle was no more than 0.60 degree. All maximum angles occurred in the second molar. Conclusion： The fixed bridge is considered to be safe. In addition, a method for measuring the rotation angle was provided effectively.     

激光熔覆技术专利分析

本文主要从激光熔覆技术国内外专利申请的申请时间、国家/地区专利申请分布、国内外专利申请人分布、激光熔覆技术存在的主要问题、解决问题的主要方向等方面进行分析研究。研究表明：激光熔覆技术国外起步较早,专利申请主要集中在欧洲、亚洲和北美,本世纪初以后出现了发展放缓;而该技术在中国起步较晚,但在本世纪初至今发展迅猛,我国激光熔覆专利分布的地域趋势较为明显,从熔覆材料方面来改善裂纹问题为主要申请方向之一,自熔性合金粉末、复合材料的研究与应用成为熔覆材料申请的热点。     

湖南瑶岗仙钨矿床流体包裹体特征及其意义

对瑶岗仙石英脉型钨矿床的石英、萤石和夕卡岩型钨矿床中石榴石流体包裹体的岩相学特征研究表明，与成矿有关的包裹体主要有三类：富液相、富气相和含子晶的多相包裹体。脉型钨矿床中石英包裹体均一温度范围为180℃-300℃，盐度O．88—6．45wt％NaCleqv；矽卡岩型钨矿床中石榴石包裹体的均一温度范围为190℃～300℃，盐度0．1～8．95wt％NaCleqv；成矿溶液的密度为0．81～0．89g／cm^3．表明形成这两种类型矿床的成矿流体均属于中温、低盐度、低密度的流体；成矿压力为120～160MPa，成矿深度约为7—9km，因此该矿床是在中高压力、中深成条件下形成的。激光拉曼探针分析表明，石英中包裹体的气相成分比石榴石中的更富含CH4、CO2和H2O等挥发份，说明流体是一种介于岩浆与热液之间的过渡性流体，具有上部偏液、下部偏浆的特点。由于该区自燕山期以来软流圈上隆，岩石圈经历了强烈的伸展、减薄作用和壳幔相互作用，而C-H还原性组分的增加，指示流体很可能来自于深部的地幔过渡带或者软流圈。