PCI-9113A在化学反应罐温度监测系统中的应用

为了解决传统温度计测量方法中存在的精度低、数据处理繁琐等问题,运用比较常规的温度传感器PT100、运放电路设计及基于PCI总线技术的9113A数据采集卡设计出一个高性能的智能式温度监测系统.该系统已经投入实际生产,运行稳定、速度快、可靠性高.     

Dimensional synthesis of a 3-DOF parallel manipulator based on dimensionally homogeneous Jacobian matrix

A study of dimensional synthesis of a 3-DOF parallel manipulator with coupling of translation and rotation is carried out.The architecture of the manipulator is composed of a moving platform attached to a fixed base through three identical PRS(prismatic-revolute-spherical) serial limbs,whose unique topology leads to the physical unit inconsistency of the conventional Jacobian matrix and the emergence of the parasitic motion.Then this paper introduces a kinetostatic performance index of the manipulator based...     

Experimental investigation on a parabolic trough solar collector for thermal power generation

Developing solar thermal power technology in an effective manner is a great challenge in China.In this paper an experiment platform of a parabolic trough solar collector system(PTCS) was developed for thermal power generation,and the performance of the PTCS was experimentally investigated with synthetic oil as the circulate heat transfer fluid(HTF).The solar collector's efficiency with the variation of the solar flux and the flow rate of the HTF was identified.The collector efficiency of the PTCS can be in ...     

Research progress of the NSFC Major Research Plan Dynamic Disaster Evolution of Major Engineering Structures

The NSFC Major Research Plan aims to conduct researches at the international research frontiers on modeling of strong earthquake ground motions and strong wind or typhoon fields, and investigating the damage and failure evolution process of the major engineering structures under dynamic actions, focusing on the following two key scientific problems: (1) characteristics and laws of strong earthquake ground motions and strong wind or typhoon fields, and (2) process and mechanism of dynamic disaster evolution ...     

棒料径向夹紧精密剪切模

通过研究剪切模具对棒料剪切质量的影响因素,设计了一种适用于普通冲床的棒料精密剪切模具,该模具通过弹簧提供径向夹紧力,且径向夹紧机构与剪切刀具设在同一模具上.模具能够提高棒料剪切断面质量及下料效率,节约了生产成本.     

Process design for multi-stage stretch forming of aluminium alloy aircraft skin

A process design approach for multi-stage stretch forming was proposed by combining the strain distribution method and finite element method (FEM) to determine the minimum stage number and deformation amount of each stage. The strain distribution method was used to calculate the deformation amount of each stage and evaluate the formability through a safety criterion. FE simulation was taken as an analysis tool to reveal the deformation behaviour, to predict the strain contour and to determine the process parameters at each stage. To evaluate the effect of heat treatment after pre-strain on occurrence of deformation defects during the subsequent deformation, a multi-stage uniaxial tension test for 2B06 aluminium alloy sheet was carried out. A case study demonstrates that the approach has high reliability and good practicability.     

Improved model and 3D simulation of densification process for iron powder

A new model for describing the compaction process of iron powder was proposed based on the continuum hypothesis and elliptical yield criterion. To simulate the densification behaviour, the constitutive model was implemented in Marc computer program. For the relationship between load and displacement, different models were compared and the influence of the parameters in the constitutive equations was determined by means of simulation and experiments. The density distribution of a balancer was measured and simulated. The results show that the parameter η adopted plays a modification role for the load-displacement curve, and compared with other models the present model fits better with the experimental data in the later stage of the compaction process mainly due to the different parameters A and B. The friction on the contact surface contributes to the inhomogeneous density distribution under large deformation of the workpiece. The comparison between the simulation and experimental data indicates that this model can be used to predict the powder compact process precisely and effectively.     

焊接特殊过程确认

焊接产品的性能只能用抽检的方式间接检测。通过对焊接产品多种性能和焊接质量的检测,甄别出全部的过程因素及其波动范围,确认焊接全部过程因素的允许波动范围是特殊过程确认的核心内容,是间接检测焊接产品性能成立的前提条件。     

基于神经网络的焊接故障诊断研究

针对焊接时容易产生气孔这个缺陷,引入了神经网络技术对气孔缺陷进行诊断,结果表明基于神经网络算法的焊接诊断稳定性好,诊断速度快,这说明该诊断技术具有很大的应用价值。     

基于OrCAD/PSpice9的电路优化设计

提出了基于OrCAD/PSpice9的电路优化设计方法,介绍了OrCAD/PSpice9的特点,通过实例借助于计算机来完成数据处理、模拟评价、设计验证等工序,实现电子系统或电子产品的整个或大部分设计过程,并说明了基于OrCAD/PSpice9环境下的电路优化设计过程。