Advanced Materials Research Vols. 472-475

Abstract: SiCp/Al composites were grinded with Diamond Wheel on high-precision machine. Acquiring grinding force signals of the experiment with High Speed Advantech PCI－1712 board. Acquired grinding force signals are analyzed in MATLAB which has mighty function disposing signals. Through analyzing the grinding force in time field, frequency field and the signals wavelet analysis for different grinding parameters, found that the feed velocity has much more influence on the grinding force, the grinding force ratio and the standard variance of the grinding force than the depth of grinding when the velocity of the Diamond Wheel is fixed. The frequency structure and energy distribution of grinding force are showed in PSD analysis. The signals are de-noised in wavelet tools. The result of the experiment indicates the grinding force increases, the grinding force ratio decreases and the standard variance of the grinding force varies complex for different material with the increasing of the velocity of the workpiece and the grinding depth.

Abstract: This paper introduces a new position method based on phase difference. The electrocircuits are designed to meet the position demand. The signal produced, phase demodulation, drive circuit are described. Lots of experiments are performed to test the linear error, hysteresis error, repeatability error and stability error. The uncertainty is synthesized based on testing data and the results show that the displacement error form electrocircuits is less than 11.2nm.

Abstract: At present, the aerostatic guide way is more and more important in the ulta-precision engineering areas, and it is analyzed in this paper. The individual stiffness of the guide, the air film stiffness and the micro-error aroused by the random air vibration of four different bearings, whose cross sections are square, triangular, trapezoid and ∏-shaped, are got one by one. A series of analysis and deductions could draw a conclusion that the aerostatic guide way with ∏-shaped cross section is recommended for obtaining the high machining and measuring accuracy, especially for the horizontal-type use and under low load. In addition, the research in this paper is valuable for the engineers.

Abstract: In order to simulate the actual roundness measurement accurately, must find the mathematical model of the actual roundness data, the paper’s main emphasis is doing statistical analysis by plenty of measurement data of roundness, using mathematical knowledge to prove that the actual characteristics of roundness parameters obey the normal distribution, and providing the basis for subsequent computer simulation in the future

Abstract: Electrochemical machining （ECM）is a kind of special processing technology which is applied widely, it is particularly suitable for difficult to machine materials, Complex shape or thin-walled parts. The principle of ECM, machining process, the electrode reaction, electrolytic processing speed are analyzed; The electrolytic processing technology and its applications are researched in detail; Research and develop directions of ECM equipment are given; The develop tendency of ECM technology is prospected finally.

Abstract: Dermatosis, a kind of common and frequent disease, is harmful to health and risk against the lives of human beings. The detection of dermatosis is of great significance, especially to the early diagnosis of skin disease. Nowadays, the studies of spectral imaging technology in the diagnosis of skin disease are attracting more and more attentions. In this paper, we firstly review some literary products related to dermatosis detection and then make a comparison among fluorescence spectrum method, filter wheel method, liquid crystal tunable filter (LCTF) method and mosaic multispectral imaging technology. Finally we propose that the smaller, lighter and more cost-effective equipment should be the trend.

Abstract: The paper designed a new small hydroelectric device after analyzing the technological characteristics and the deficiency of the existing hydropower. As a supplement of conventional power, the device can be used in the places that have no conditions to build dams but have a lot of water resource. The new device working principle was introduced and the analysis of its force and motion was made. The design scheme is proved feasibility through theoretical analysis. The model test indicates that this new hydroelectric device has high efficiency.

Abstract: Reported in this paper is an investigation of the process parameter effects on surface roughness and subsurface damage (SSD) in CMP of single crystalline Silicon. For the given experiments, the appropriate method to examine the SSD can be obtained. The surface roughness and figure accuracy were measured with an atomic force microscope (AFM) and Taylor-Hobson profilometer. The experiments results indicate proper process parameter for the best surface roughness, which can be divided into two stages. It should use longer time in the finish polishing stage, while shorter time and reduce the ratio of polishing pads and head in the ultra-finish polishing stage. Generally speaking, the isotropic etching of single crystalline Silicon, anisotropic etching of single crystalline Silicon and hand burnishing are mostly used to find the SSD and it is found that the last method is the best one to see the SSD by SEM.

Abstract: Non-Subsampled contourlet transform can extract image texture information more efficiently than basic contourlet transform and has been studied for image de-noising, enhancement, and retrieval situations, its low retrieval rate are still not satisfied due to feature extraction and other reasons. Focus on improving the retrieval rate of non-subsampled contourlet transform retrieval system, a new feature named variance distribution was proposed and then a non-subsampled contourlet retrieval system was constructed in this paper. The feature vectors were constructed by cascading the energy and variance distribution of each sub-band coefficients and the similarity measure used here was Canberra distance. Experimental results show that using the new features can make a higher retrieval rate than the combination of standard deviation and energy which is most commonly used today under the same retrieval time and hardware complexity.

Abstract: The as-cast and friction stir processed (FSP) hypereutectic AlSi29Fe3 were reheated to the semi-solid state, the coarsening dynamics of the Fe-rich phase during the process of remelting were investigated by the means of quantitatively metallurgical analysis. The results indicated that the coarsening of the Fe-rich phase in semi-solid state for both microstructures followed the Lifshitz-Slyozov-Wagner (LSW) theory:. However, the coarsening exponent n of the Fe-rich phase in the as-cast microstructure was 3, in the FSP microstructure was 2. Therefore, the growth rate of the Fe-rich phase in the FSP microstructure was larger than in the as-cast microstructure. In the meantime, the morphology of the Fe-rich phase changed to short bar from granular in the FSP microstructure.