基于 NI CompactRIO 的多通道磁场采集系统的设计与实现

针对磁法勘探、地磁导航等不同技术领域的地磁测量需求,提出了一种多传感器模块化采集方案,构建了基于NI CompactRIO的多通道磁场采集系统.系统整合了光泵磁力仪,磁通门磁力仪,惯性导航模块以及GPS模块,可满足不同情况下的实验需求.为了解决多传感器组件同时采集时数据无法同步的问题,提出了基于GPS的同步授时技术以保证数据的有效性.利用插值计数器实现了数字倒数插值测频法,在铯光泵磁力仪有效输出范围内,磁测分辨率优于0.006 nT.在吉林大学电磁屏蔽室中,对系统噪声水平进行了评估,评估结果表明采集系统的PSD为7 pT/Hz@1 Hz,符合设计要求.最后在长春南湖和内蒙古桃合木苏木两个实验场地应用采集系统,验证了系统在野外恶劣环境下能够稳定工作,并高效地完成采集任务.     

基于红外线光电开关的测速系统设计与应用

随着现代科技的不断进步,各个领域对测速系统的应用越来越多,同时也对测速精度的要求日益苛刻。文中提出一种基于红外线光电开关的测速系统,采用NI6251高速数据采集卡以及LabVIEW软件设计代替了传统的基于单片机或FPGA等自行设计的硬件电路所组成的数据采集分析系统,提高了测速系统的可靠性和测量精度。文中介绍了整个测速系统的工作原理、结构设计和软件设计,并进行了系统的误差分析。现场试验结果证明,该方法能够将高速直线运动物体的测试误差保证在0.0015%以内。     

变截面纵剪机组中的运动控制应用

为实现变截面纵剪机组的高精度控制,本文设计了采用NI运动控制器的剪刀盘控制系统,即以PXI控制器为硬件平台,以运动控制器为核心控制部件,利用多功能采集卡采集传感器信号,在软件平台LabVIEW上实现了对剪刀盘的运动控制。实验结果表明:该运动控制系统运行稳定,抗干扰能力强,对控制策略适应性强,具有易扩展、易维护等特点,适合广泛应用在运动控制领域中。     

Process and compressive properties of porous nickel materials

Abstract

Compressive properties are investigated for the porous Ni materials processing by innovated powder metallurgical (PM) method. The porous Ni materials first show a short elastic region, then a long and oblique stress yield region within the strain range of about 10–50%, and finally, a densification region where the stress increases rapidly.     

Multipass rolling of aluminium alloys: finite element simulations and microstructural evolution

Abstract

Use of numerical predictive methods such as finite element analysis is becoming progressively more common for modelling industrial hot metal working and forming processes. These tools are used not only to predict the thermomechanical behaviour of metals but increasingly to predict microstructural changes by linking them to physical models of recrystallisation and textural evolution. This paper describes the development and application of a fully integrated model for the prediction of thermomechanical and microstructural behaviour during multipass hot rolling of aluminium alloy AA 3104. Finite element code ABAQUS/standard has been used in the work and the process is modelled assuming plane strain conditions. It is shown that for this alloy the static recrystallisation which occurs during interpass cooling does not significantly influence the thermomechanical response during subsequent rolling passes.     

用Matlab控制NI数据采集卡实现实时数据采集

为实现在M atlab环境下应用N I数据采集卡实现实时数据采集,提出了通过链接动态链接库,在C-MEX文件中调用N IUSB-6008数据采集卡的驱动函数,成功驱动数据采集卡获取数据。该方法的使用,为M atlab控制其他高性能数据采集卡提供了有益的操作思路。     

Examination of HA230 turbine transition duct

Abstract

The present paper reports the results of an examination of a service run transition duct from one of Siemens' industrial gas turbines and the correlation between the findings for this, and those from the studies undertaken on laboratory exposed Haynes alloy 230 material. The studies have shown that there are changes in the microstructure and hardness of the material that can be related to temperature and time of exposure, and the information gained can lead to estimations of the average component operating temperature. Metallographic studies revealed a high level of heterogeneity of the grains in this transition duct.     

Periodic reverse current electrodeposited nickel pigmented anodised aluminium

Abstract

Aluminium anodically oxidised in sulphuric acid electrolyte was pigmented by an electrolytic colouring process with the use of alternating and periodic reverse current. The applied pigmentation electrolytes were based on nickel. The study reports on resistance against humidity of a selective Ni–Al₂O₃ layer. The samples before and after testing were analysed and compared. The quality of the coating, optical properties and influence of humidity on morphology and composition of the coatings were investigated. The influence of moisture on the quality of the selective Ni–Al₂O₃ layer is comparable to the commercial solar absorber type.     

Nanocrystalline zinc–nickel alloy deposition using pulse electrodeposition (ped) technique

Abstract

Zinc–nickel alloy was electrodeposited on stainless steel using pulse current deposition (PED) from a chloride–sulphate bath. Duty cycles were varied between 10 and 80% and frequency was changed from 10 to 100 Hz. The deposit characteristics were analysed using SEM, XRD and AFM and the results are presented in this paper. The corrosion resistance of zinc–nickel alloy deposited from direct current deposition (DCD) has been compared with that of the deposit obtained by pulse current using the electrochemical impedance spectroscopy method.