Improved direct bonding method of Nd:YVO4 and YVO4 laser crystals

We succeeded in the fabrication of bonded laser crystals composed of a neodymium-doped YVO₄ laser crystal (Nd:YVO₄) and its host crystals YVO₄ by a newly developed dry etching technique using an argon ion beam. The optical distortion caused by the bonded interface of size 5 mm × 6 mm was estimated to be 0.05λ at 633 nm. From the comparison of laser performance pumped by a laser diode, the bonded crystals could increase the laser output power by nearly twice that of the non-bonded crystals with the same degree of polarization of 99.2%. To analyze the mechanism of the enhanced reduction of the thermal load in the bonded crystals, numerical simulations with a finite-element method were also performed.     

PSD激光直线度测量仪

介绍了采用PSD传感器设计的激光直线度测量的工作原理，以及激光器、光靶和计算机系统的设计。     

连续激光引起高空中动态靶材破坏的理论计算

本文在文献[1]和[2]的基础上,考虑动态靶目标是受载结构的影响,综合考虑大气吸收、散射、湍流及热畸变效应对激光传输的影响,计算了连续激光引起高空中动态靶目标的破坏阈值。     

激光辐照对不同饵料微藻生长的影响

利用Nd:YAG激光(波长1.06μm,功率5W,照射时间0.5-3min)和Ar 激光(波长:488nm,功率70mw,照射时间5-20min)分别照射角毛藻和叉鞭金藻,辐照后进行细胞增殖和生长速率的测定。实验结果表明:照射剂量为1min的Nd:YAG激光及剂量为5min的Ar 激光对叉鞭金藻有较明显的促长效果,这两种激光处理组的细胞增殖量在辐照后的两天内较对照组分别高42.9%和48.1%,但这种促长效果随时间的推移逐渐消失。不同剂量的两种激光辐照角毛藻后,在延滞期均出现生长抑制现象,但进入指数生长期或传代培养后,剂量为1min的Nd:YAG激光及剂量为10min的Ar 激光对角毛藻有明显的促长效果,其中在指数生长期1min剂量的Nd:YAG激光处理可促长27.0%,传代培养后10min的Ar 激光处理组生长速率提高达51.2%。本文对不同激光及不同激光参数条件下,两种饵料藻的耐受性及生长特性的差异也进行分析探讨。本实验结果不仅证实了已有研究的推论,还展示出激光技术在饵料藻种选育中的应用前景。     

Combination of coating and heat treatment processes

For a proper use of coated tools and components excellent coating properties as well as excellent substrate properties of the coating/substrate composite are necessary. A well known example is the load support of hard steel substrates for thin wear resistant coatings. Therefore coating processes must be combined with heat treatment processes of the substrates, whereby several practical processing constraints like order and compatibility of the applied treatment procedures must be considered. The combination of CVD-coating plus laser beam hardening is an example of a post coating heat treatment. Applications may be possible for large forming tools made of high alloyed tool steels, which nowadays are usually through hardened after CVD-coating. Laser beam hardening offers the possibility, to harden only the highly loaded edges of the tools. The advantages of this combination are short process time, less distortion and compressive residual stresses in the substrate surface. CVD-coatings can endure laser beam hardening with suitable parameters. The influence of CVD TiN-coated steel substrates and laser beam hardening parameters on microstructures and properties of coating/substrate compounds have been investigated. Special attention was paid to overlapping hardening zones, which may occur at the start and end points of a laser hardened track. In summary, the combination of coating and heat treatment processes show a high potential to produce coating/substrate compounds with excellent coating properties as well as excellent substrate properties.     

LASER ENHANCED ELECTROCHEMICAL MACHINING PROCESS

An experimental apparatus was designed and built for the hybrid process of laser enhanced electrochemical machining (ECM). Comparison experiments had been done between solely ECM and laser enhanced ECM. The machining performance of hybrid process was investigated and compared with solely ECM. The principle of the hybrid process was exposed by analyzing the microstructure of machining surface. The results show that the hybrid process has advantages in machining accuracy, surface quality, and machining efficiency.     

激光起爆与点火系统中光纤连接器

介绍了激光起爆与点火系统中光纤连接器的原理、种类、技术特性及损耗，并对激光起爆与点火系统中光纤连接器的研制动向进行了概括，最后得出一些结论。     

Effect of C/Ti ratio on the laser ignited self-propagating high-temperature synthesis reaction of Al-Ti-C system for fabricating TiC/Al composites

TiC/Al composite was successfully synthesized utilizing laser ignited self-propagating high-temperature synthesis (SHS) of Al-C-Ti system with the different C/Ti molar ratio. When the molar ratio of C to Ti is below 1:1 in the starting materials, in addition to fine TiC particulates, a large amount of Al₃Ti phase was found in the composites; however, when the molar ratio of C to Ti is 1:1 in the starting materials, the Al₃Ti phase was almost completely eliminated and the distribution of TiC particulates generally appeared to be more homogeneous throughout the products synthesized.     

曲轴激光喷丸强化试验研究

采用实验的方法,研究了激光冲击强化对175A型柴油机曲轴疲劳寿命的影响,取得了激光冲击强化试验条件下曲轴过渡圆角处残余应力场的数据。并将激光冲击强化工艺效果和曲轴滚压强化效果做了对比性分析,结果表明：虽然激光冲击强化效果不如曲轴滚压强化,但考虑到激光工艺参数精确可控、加工质量好、成本低以及可避免滚压强化所造成的表面疲劳、撕痕等,激光冲击强化工艺可望代替滚压强化成为新型的曲轴强化手段。通过此类激光冲击强化强化实验可优化激光冲击的相关参数,使曲轴过渡圆角产生有利的残余应力场。     

一种激光测厚装置

介绍一种新型激光测厚装置 ,描述了它的结构框架及工作过程