Mass spectrometer is one of the most versatile tools in current analytical science, which can perform both qualitative and quantitative chemical identification with high sensitivity, high accuracy and low consumption. Currently, the development of miniature mass spectrometer has received growing interest, since it provides a rapid way for online detection and real-time analysis. Quadrupole analyzer has been widely used in quantitative analysis, and it can be easily miniaturized for the purpose of developing portable mass spectrometers. A portable quadrupole mass spectrometer was developed for in-situ analysis, which can perform both qualitative and quantitative analysis for solid or liquid samples in atmospheric conditions.

The liquid floating rotor gyro is a gyroscope using electrostatic or electromagnetic forces to levitate rotor, and filling rotor-stator cavities with liquid in order to improve stability of motion. Under influence of the relative surface roughness, rotor velocity, dimension of flow field and fluid nature, flow characteristics of cavity flow field vary under different boundary conditions and geometrical conditions. This paper adopts three-dimensional model and periodic boundary conditions to conduct numerical modeling on cavity flow field. Its results show that, with velocity rising, distribution of flow field speed and pressure manifests partial fluctuations in turbulent-flow-intensive area; resistance torque amid rotor rotation is nonlinearly correlated with velocity, whose rules can be obtained through high-order curve fitting.

Travelling wave wall used for Micro Air Vehicle flow control is studied to find out its drag reduction effect. Aerodynamic characteristics of the airfoil with and without a streamwise travelling wave on its surface are calculated. The interrelationship is also analyzed among lift, drag and ratio of motion phase speed to the external flow velocity. The flexible airfoil that can generate streamwise travelling waves is realized via electromagnetic coil actuation. Thirty-six coils are placed streamwisely under heat shrink film and magnets producing magnetic field are placed under coils. Every single coil is controlled by current to move vertically in harmonic motion with 30 degrees phase difference between adjacent ones. So heat shrink film is actuated, and streamwise travelling wave is generated. Meanwhile, a prototype is designed and tested in wind tunnel. The experimental aerodynamic data proves that streamwise traveling wave airfoil can increase lift and reduce air drag.

A novel ball-end mill manufacturing algorithm of 5-Axis CNC Machining grinder and the simulation test of the algorithm based on a CAD system are presented in this paper. In order to obtain an accurate algorithm of a ball end mill machining, a mathematical model is needed so that the shape of the mill can be parameterized. Therefore, the mathematical model can be adjusted based on that model. Each of the processing parts has its own position in the local coordinates system. Then, with the coordinates determined by the mathematical model, the partial coordinate and the relative movement between the grinding wheel and the barstock in the local coordinates system can be calculated. So that the 5-Axis manufacturing coordinate can be confirmed by the partial coordinate and the structural parameter. If we input these data and make the 3D-CAD simulation before the machinery manufacture, the algorithm can be tested effectively.

No abstract