圆锥形接触式激光刀头设计

本文用展开法设计圆锥形接触式激光刀头,导出了刀头几何参数的计算公式。给出了一个设计实例并讨论了各几何参数之间的关系。     

桩孔内钻头配重的爆破切割打捞

肇庆大桥 40 #D桩位于西江江中心。施工中 ,钻头在 -3 2 99m处被地下溶洞卡住。钻头及其配重的质量共 17t,需要打捞。在 3 6m深的泥浆中使用切割爆破法 ,使配重与钻头分离 ,并成功地将配重打捞出水。由于孔内空间有限 ,爆破技术难度大。本文介绍了爆破方案设计、药量确定、药包布置方式 ,并指出了尚待研究的问题     

核阀密封面激光熔覆层耐磨性能研究

采用 5KW横流CO2激光器对 1Cr1 8Ni9Ti核阀密封面进行了钴基合金激光熔覆处理 ,测试了激光熔覆层的耐磨损性能 ,并将其微观结构及质量、耐磨损性能与等离子喷焊处理的同种试件进行了对比分析 ,结果表明 :激光熔覆层具有更高的抗擦伤磨损和抗高温冲击滑动磨损的性能 ,具有组织细密均匀、晶粒度高、硬度高与稀释率低的特点。在此基础上对激光熔覆层的耐磨损性能进行了分析探讨     

脉冲激光焊接技术及在集成电路制造中的应用

综述介绍了脉冲激光作为热源用于焊接的工艺特点，以及激光束质量或模式对焊接质量的重要意义。简要总结了国内外集成电路制造中脉冲激光焊接技术的应用和发展情况。     

焊缝激光跟踪图像处理中关键技术的研究

在焊缝激光跟踪实时图像处理中,采用卷积滤波和中值滤波相结合的方法,提高了中值滤 波能力和处理速度;采用Robert算子,较好地保留了激光光带的边缘;采用左右边界平均值来抽取激光带中心线简单易行;用斜率分析法来检测特征点方便可靠。该图像处理技术效果好能够满足跟踪系统的实时性要求。     

Extraction and collection of laser photoionized neodymium ions measured by the multichannel Faraday cups

In order to effectively extract and collect photoionized ions generated by the laser irradiation of atomic beam, five sets of semicylindrical electrode pair were added to the ion extractor, and the obtained ion intensity distributions were measured by scanning multichannel Faraday cups. By applying potential difference between the additional electrodes up to about 1300 V for ion collection, the laterally broad distributions of the extracted ion beam were collected both vertically and horizontally, and the central ion beam flux was intensified.     

The influence of laser welding parameters on the microstructure and mechanical property of the as-jointed NiTi alloy wires

The Nd:YAG laser welding was used to join the binary NiTi alloy wires with different compositions(Ti-50.0 at.%Ni and Ti-50.9 at.%Ni) which had the same diameter of 1 mm. The wires were welded with different parameters, including impulse width and welding current. The aim was to assess the influence of the laser-welding process on the microstructure and mechanical properties of the welded joint of binary NiTi wires. The optical microscopy (OM) and the metallographic microscopy (MM) were used to analyze the microstructure of the welded joints. The tensile test and the differential scanning calorimetry (DSC) were carried out to examine the ultimate tensile strength and the reverse martensitic transformation temperatures of the welded joints. It was found that the welding current and the impulse width had great influence on the quality of the welded joints, an optimal parameter combination would remove the pores and micro-cracks appeared in the fusion zone, and result in good mechanical properties such as higher fracture strength and elongation. The laser welding had a few effect on the reverse martensitic transformation temperatures of the welded joints.     

3D characterization of super-smooth surfaces of diamond turned OFHC copper mirrors

In this study, super-smooth surfaces of oxygen-free high-conductivity copper mirrors obtained by single point diamond turning were characterized with an atomic force microscope from the three-dimensional (3D) point of view. The machining conditions were also studied. A program developed in this study for a unified approach to 3D surface finish assessment proposed by the Commission of European Community was used to obtain the 3D parameters. In two experiments, the feed rate was changed from 0.2 to 2.0 μm per revolution and 0.3 to 3.0 μm per revolution, respectively. By 3D roughness characterization of these surfaces, the optimal feed rate was found to be 1.4 μm per revolution when the cutting depth was 1 μm or 0.9-1.2 μm per revolution at a cutting depth of 2 μm, where an S_q of 2.6 and 2.3 nm could be obtained, respectively. The suggested 3D roughness characterization parameters may include S_q, S_sk, S_ku, S_tr, S_al, S_Δq, and one functional parameter, such as S_bi.     

半导体激光器与新材料

介绍了半导体激光器和半导体光电材料研究的新进展。     

Failure analysis of multilevel metallized lsi using optical beam induced current

In order to analyse failures caused in multilevel metallized LSI devices. we developed the OBIC (optical beam induced current) observation technique using an infrared laser incident upon a backside of the chip which appears from a plastic package by being lapped and polished. We analysed the electrical rejects in the reliability stressing of surface mount plastic packages with this technique. The latch-up phenomenon in 4Mbit dynamic RAM with retrograded-well fabricated by a high energy (MeV) ion-implantation was also examined. The high latch-up immunity of the device with retrograded-well is confirmed by this analysis.