硬脆性无机材料激光成形加工研究与应用现状

硬脆性无机材料激光成形加工是激光加工技术最有前途的领域之一。本文综述了国内外在硬脆性无机材料的激光成形加工方面的研究成果和应用状况，并展望了无机材料激光成形加工的研究与应用前景。     

Spherical distribution structure of the semiconductor laser diode stack for pumping

A semiconductor laser diode stack is used for pumping and 8 semiconductor laser diode arrays of the stack are put on a sphere,and the output of every bar is specially off-axis compressed to realize high coupling efficiency.The output beam of this semiconductor laser diode stack is shaped by a hollow duct to the laser active medium.The efficiency of the hollow light pipe,which is used for semiconductor laser diode stack coupling,is analyzed by geometric optics and ray tracing.Geometric optics analysis diagnoses the reasons for coupling loss and guides the design of the structure.Ray tracing analyzes the relation between the structural parameters and the output characteristics of this pumping system,and guides parameter optimization.Simulation and analysis results show that putting the semiconductor laser diode arrays on a spherical surface can increase coupling efficiency, reduce the optimum duct length and improve the output energy field distribution.     

基于衍射/反射光束整形系统的高密度泵浦源

利用二元光学元件微型化和对波面进行任意整形的特点,将二元光学衍射器件用于高功率激光二极管阵列光束的快、慢轴准直,并结合空心导管设计一种衍射/反射混合型光束整形系统,用于实现高密度、高均匀性LD泵浦源.应用时域有限差分法(FDTD)的严格矢量分析表明:所设计的二元光学准直器性能优良,准直后光束发散角在误差范围内接近衍射极限,慢轴方向衍射效率为82.21%,快轴方向为75.76%.模拟设计的结果表明:采用这种衍射/反射光束整形技术的高密度泵浦源能获得高功率密度和高均匀性的抽运光束,在空心导管出射端面附近光强起伏RMS<1%,并且在光束的准直性能和系统紧凑性方面优于传统整形方法.     

双缸同步提升电液系统建模和控制

以浙江大学研制的智能钢管捆成形系统为背景,针对电液提升系统的双缸同步运动问题,提出一种两级非线性控制算法.该控制器的外环级采用一个线性多输入多输出的鲁棒控制器,用于获得双缸运动同步控制所需的各缸期望负载压力;内环级采用两个基于扰动估计观测的单输入单输出液压缸非线性压力控制器,用于在有扰动情况下实现对每个提升缸期望负载压力的精确跟踪控制.实际的控制运行结果表明,该控制策略优于常规的PID控制,可以有效地实现双缸运动同步控制.     

压力钢管焊接变形控制

系统概括了压力钢管焊接变形的影响因素及控制对策,结合实例阐述了有效控制焊接变形的关键在于控制线能量,采用合适的制作工艺。     

长输管道管沟成型施工技术

在简述长输管道管沟成型的方式和技术要点的基础上,从理论和实践两个方面对管沟埋深不够和管道损伤等质量通病进行分析论证,并提出相应的整改措施和质量控制方法。     

Inclusion of fatigue effects in human reliability analysis

The effect of fatigue on human performance has been observed to be an important factor in many industrial accidents. However, defining and measuring fatigue is not easily accomplished. This creates difficulties in including fatigue effects in probabilistic risk assessments (PRA) of complex engineering systems that seek to include human reliability analysis (HRA). Thus the objectives of this paper are to discuss (1) the importance of the effects of fatigue on performance, (2) the difficulties associated with defining and measuring fatigue, (3) the current status of inclusion of fatigue in HRA methods, and (4) the future directions and challenges for the inclusion of fatigue, specifically sleep deprivation, in HRA.     

陶艺的嬗变——浅论现代陶艺的创作

不同时代的作品有着不同的艺术风格和工艺特点。现代陶艺的创作在工艺技术方面吸收了传统陶瓷艺术的装饰技法、成型方法,其现代是表现形式的现代和概念的现代。我们应该把握好传统与现代的融合,注重创新与传承的关系。     

四环阵天线的分析及其方向图赋形设计

四环阵天线技术 ,从美国引进以来 ,在 15 0 - 40 0 M频段各类通信系统中 ,已得到了极为广泛的应用 ,但迄今为止 ,尚未见到对这种天线进行讨论的专门文献。作者根据多年来的实践工作与设计经验 ,对四环阵天线进行了基本的分析 ,特别是对有重要实用价值的赋形波瓣异型四环阵的设计进行了充分的讨论。     

Cross-coupling position command shaping control in a multi-axis motion system

A new structure of a cross-coupling position command shaping controller (CPCSC) for precise tracking in multi-axis motion control is proposed in this paper. This controller feedforwards the cross-coupling terms, based on the geometrical relationship between the tracking and contouring errors, to compensate for the contouring error in real-time. Compared with the conventional multi-axis cross-coupling control (CCC) system, this new structure has the advantage that its compensators in CCC have a simpler design process than conventional ones, as does its stability analysis. The proposed controller is evaluated and compared experimentally with a traditional uncoupled and a conventional CCC controller on a multi-axis positioning system controlled by microcomputer. The experimental results show that the new structure remarkably reduces contour error. In addition, this new controller can be implemented easily on most current systems by reprogramming the reference position command subroutine.