Papers by Author: Xiao Jing Yang

Abstract: The experiment of cutting mechanical properties of single crystal silicon surface in the micro-nanoscale is researched using nanoindenter and atomic force microscopy. The result of the experiment shows that: in the constant load, the impact of different scratching velocity for single crystal silicon surface scratch groove width and chip accumulation volume are not big; but the cutting force and friction coefficient are not increases with the scratching velocity increases; when the scratching speed is certain, the size of load has a greater impact on the cutting mechanical properties of single crystal silicon surface, with the increase of the load, the cutting force increases, but the cutting force is not linearly growth.

Abstract: Atomic Force Microscope (AFM) works by the force between the probe tip and specimen surface. The nanocontact force between the probe tip and specimen surface has an important influence on the detection surface. Base on the analysis of the working principle of the AFM and nanocontact force calculation model, according to Hamaker assumptions, using continuum method established the theoretical contact force model of the AFM tip. the contact force calculation methods of contact pressure in process has been obtained. The variation of the force between the probe tip and specimen surface has been found by calculation model and programming calculation of Matlab. Provide the basis for improving the accuracy of an atomic force microscope surface inspection and error analysis

Abstract: The feed drive system is important functional components which effects on precision and efficiency of transmission and cost of CNC milling machine tools. So the designe of the feed drive system of economical CNC milling machine tool is researched. Firtsly the general design scheme which includes the transmission scheme and basic parameters of CNC milling machine tool is determined. Then according to the milling force calculated during mill processing, linear rolling guide, ball screw and stepping motor of X axis and Y axis of feed drive system are respectively calculated, selected and checked in detail. Using the Solid works software for 3D modeling and assembly of mechanical parts of feed drive system, By the scheme comparison, selecting the CNC system of Huazhong century star HNC-21 and accomplishing the electrical connection of CNC system.The feed drive system of economical CNC milling machine in the desing is high performance and low cost,and meet accuracy requirement.

Abstract: The finite element method and nanoindentation experiment are used in this paper, to analysis mechanical properties of monocrystalline germanium on micro/nanoscale. The cloud charts of stress and strain distribution are obtained by finite element method. It is shown that the depth increment of the contact makes the value of stress and strain in the surface layer greater and the area of action larger in the process of nanoindentation of monocrystalline germanium. In the nanoindentation experiment, load and displacement curve is different with different crystal orientations. With the increase of load, contact depth has been increased. The residual deformation depth of three crystal orientations is also different. The results of FEM is is closed to the crystal orientation of [100].

Abstract: By employing the ASCII type communication protocols between MCU and KingView provided by WellinTech Inc, basing on the analysis of COM port setting and command format of read-write operation between MCU and the KingView, this paper design a read-write operation on floating point data program with C programming language and realize the real-time communication between MCU and KingView successfully, which improved the accuracy and scope of data transmitted between them. Data definition and some key subprograms like serial ports initialization, read floating point data from MCU, write floating point data to MCU are provided in the paper. It has high portability and application value.

Abstract: The research of the nano-mechanical properties on mono-crystalline silicon by nanoindention technology is reported in this paper . Using the calculation method given by Oliver and Pharr, the hardness and the elastic modulus of mono-crystalline silicon are gained from the load-penetration depth curve. The simulation on mono-crystalline silicon in the plastic phase is carried out by ABAQUS. Based on the bilinear constitutive law and approximate relationship between the hardness and the yield strength, the obtained load-penetration depth curve through the finite element method is compared with the materials actual load-penetration depth curve and good correlation is achieved.

Abstract: Soil is one of the important mediators in the agricultural production and its particle is a discontinuous, heterogeneity and nonlinear natural geological substance. It is difficult to analyze the soil cutting process by using traditional methods. According to the discrete nature of the agricultural soils, discrete element method based on the discontinuity assumptions can be an alternative to analyze the changes under external forces in the soil cutting process. This article describes the basic principles, its applications and its prospects of the discrete element method, especially in the field of soil cutting.

Abstract: In order to explore the application of multi-sensor fusion technology in nondestructive testing of agricultural products and develop new detection methods for agriculture, multi-sensor information fusion technology are performed to identify freshness of freshwater fish meat. Different freshness of grass carp specimens were identified by multi-sensor fusion method which three characteristic data that are PH value, conductance and smell were measured, collected, and then fused by fuzzy theory method. During the experiment process the value of the total volatile basic nitrogen (TVB-N) of standard samples and test samples were measured. The freshness standard was established by the TVB-N value of standard samples. Correctness of the results of multi-sensor data fusion was verified by comparing the TVB-N value of the test samples with the freshness standard. The results show that the freshwater fish meat with different freshness can be identified correctly by multi-sensor data fusion method which is fuzzy theory and the accuracy rate is 94%.

Abstract: The experiment of mechanical characteristics of sliding contact in nano-scale was researched using nano-indenter. The displacement-friction curves with different loads and sliding velocities were given through the contact effect between diamond indenter and mono-crystalline silicon test-coupon. The three-dimensional AFM morphologies were obtained through scanning contact area by AFM. The research shows that the contact-force and friction increase along with the increment of loads, in condition of sliding with different loads. The friction increases along with the increment of sliding velocity, in condition of different sliding velocities. Otherwise, furrow destruction along with obvious plastic flow is generated with low sliding velocity (100μm/s). However, the oddments accumulate obviously on the verge of nick with high sliding velocity (above 100μm/s), and the phenomenon of oddments accumulating is more obvious along with the increment of sliding velocity.

Abstract: The bearingless motor combined technical characteristics of motor and magnetic bearings. It can simultaneously implemented electromagnet torque control and suspension control all in the motor .Since there are two sets of windings wound on the stator of bearingless motor, two sets of power circuit hardware and controller are required. In the case of most conventional structures, each terminal controller calculate references by themselves and transmits a torque/positon interactively. However, the latency issues of data delivery latency affecting the decoupling between the air-gap flux.The paper proposed the structure for a torque/positon hybrid control through network, torque/positon is transmitted from each terminal controller to a central controller. Then the central controller calculates references that are feedback to the terminal. The delay time is eliminated. In the paper, the hybrid control of bearingless induction motor is realized with the digital system based on the TMS320F2812.