Gui Tang Wang

Formation of porous hydrophobic stainless steel surfaces by maskless electrochemical machining

Surface topography is an important feature, which directly affects the friction, corrosion and flow characteristics of a workpiece. In this study, a new approach was explored to produce a microporous structure by maskless electrochemical machining (ECM). A rough surface with a microporous structure was created on a stainless steel substrate, and the principle of the micropore formation was investigated. It was found that the microporosity could form, grow and interconnect when the potential of the anodic surface was higher than the pitting potential of the material. The electric field is an important factor, and the surface topography can be altered by changing the electrical parameters. The porous microstructure was observed by laser scanning confocal microscopy. The rough and porous surface, modified with 1-dodecanethiol, exhibits hydrophobic characteristics, with a static contact angle of 137° for water droplets. This is a significant improvement in the wetting properties for stainless steels.

Application of Order Analysis in the Analysis of Noise in Automobile Alternator

With the increasing request of the comfort, reduce the vibration and noise of automobile AC generator as the industry wide concern. In this paper, based on a type of vehicle alternator speed section of excessive noise problems, using order analysis method on noise generator is analyzed, the main harmonic component generator noise for 36 harmonic components, and determine the maximum value of the resonance speed noise in 1800rpm, 2400rpm, 3400rpm near the motor load state. On this basis, puts forward the corresponding improvement measures to improve the motor, the motor noise value to the manufacturers standard.

An Improved Multi-Label Anti-Collision Algorithm of RFID

When there are multiple electronic tags in the reading range of reader, It arises problem of multiple tags data collision in the data communication process of RFID system, causing the data reader have obtained error. This paper will contrapose the problem of tag collision, analysizing the search number and the system throughput rate of the existing anti-collision search algorithm based on binary, to propose an improved anti-collision algorithm. The improved algorithm reduces the redundant information of the sequence number that the reader have sent, and no longer searchs the tags of one bit collided ,but identify the two collided tags directly, thus reducing the search number of algorithm. Matlab simulation show that this algorithm can reduce the search number of reader identifying tags, improving the identifying efficiency of the RFID system, solving the problem of tag collision effectively.

Pistol Ring Gap Inspection under Free State Based on Machine Vision

The traditional way is to put the ring into the standard ring gauge to inspect, but the process of this kind of method is complex, high cost and slow. The study has put forward a detection method based on machine vision technology for pistol ring under free state as the existing defects in inspecting ring gap. Pistol ring is imaged under free conditions. Edge detection technologies, sub-pixel and Gaussian filter, have been effectively adopted to extract the contour of pistol ring. Then perform curve fitting in section to work out the gap length of each segment when pistol is circle. From the experiment, methods in this study are pertinent to the number of the segments. Proper segments can ensure gap length can be rightly calculated out when meeting the required accuracy. Sub-pixel edge detection is proposed in the application of piston ring detection in this study, and it improved the previous algorithm toimprove the efficiency ,reduced the process complexity, saved the cost.

The Demodulate and Denoising of Vibration Signal under very Noise Condition

For the failure diagnose of onsite mechanical equipment, which based on vibration noise in section, both characteristic signal and noise influence were contained in vibration signal, which all accepted by the machine. The problem arise when the characteristic signal was weak compare with the useless noise, the useful signal becomes hard to obtain, hence result in lower accuracy of the equipment. In this thesis, a new method based on the delayed autocorrelation demodulation method was analyzed and will be used on demodulation noise reduction: Based on the noise reduction feature of autocorrelation function, the related analysis was taken on vibration signal, then the autocorrelation function for the signal was obtained. Then with proper delay on autocorrelation function to avoid noise effect and envelop demodulation, we could achieve the demodulation result. The theoretical analysis and simulation experiments has proven the delayed autocorrelation demodulation method achieve better anti-noise performance than direct demodulation method, meanwhile, the delayed autocorrelation demodulation method could also highlights the characteristic information.

Research on Testing Technology of CMOS Camera Module

After the completion of the CMOS(Complementary Metal-Oxide-Semiconductor Transistor) camera module assembly,in order to test the image quality of module. In this paper, based on the ISO12233 standard chart proposing a CMOS camera module modulation transfer function MTF (modulation transfer function) of test method, MTF average value calculated for each module with high contrast and grayscale method, and validation processing to detect unqualified imaging module. The results show that MTF detection method used in this paper can quickly and accurately detect the quality camera module, and stable and reliable, playing an important role to found the quality problems and improve the efficiency of production.

Application of Wavelet Packet Energy Spectrum in Micro Motor Fault Diagnosis

To diagnosis vibration signals of micro motor in several different fault types a method based on wavelet packet energy spectrum is presented, the energy on each Sub-frequency band, which are Calculated by Wavelet packet decomposition and reconstruction algorithm, are used to normalization process.Under both circumstances of normal working and unmoral working of mechanical equipment,there exist evident differences among the Sub-frequency band energy after the decomposition of wavelet packet, which energy contains a wealth of micro motor running status information and the eigenvectors is structured by the Sub-frequency band energy spectrum can establish energy and Fault mapping relationship.The preliminary experimental results show that it is effective to use the wavelet packet-energy spectrum in micro motor fault diagnosis .

Research on a Real-Time Fault Tolerant Time Synchronization Algorithm for GSM-R Wireless Sensor Networks Based on Network Materials

Time synchronization is a key technology in wireless sensor networks. In this paper, aim at high-speed railway GSM-R network require higher real time, fault tolerance and band coverage way, presents a real-time fault-tolerant wireless sensor network time synchronization algorithm, using direct forwarding strategy, regression analysis and abnormal data filtering methods to meet the requirements of GSM-R network. Analysis and simulation show that the algorithm has good real-time and fault tolerance to meet the requirements of GSM-R network applications.

FPGA Implementation of Laplacian of Gaussian Edge Detection Algorithm

This paper introduces a design of gaussian Laplace edge detection algorithm model based on system generator which can be realized in FPGA.The data of a two- dimensional image was changed into a one-dimensional array，before line buffering in two Dual port RAM,the convolution of the image pixel data and the LOG template was carried out in the modules constituted of the component elements such as AddSub, Shift and Delay . After getting the absolute value with the modules of Slice，Negate and Mux ，the output was the image after edge-detection .The module function and the selecting principle was analyzed from the point of view of saving FPGA resources.The WaveScope and resource estimator showed that ：not only the detection result and the running speed was guaranteed but also the FPGA resources can be saved .

An Optimal Process for Ultrasonic Amplitude Transformer Design with FEM

The amplitude transformer is one of the most important parts in ultrasonic work system. To amplitude transformer, the resonant frequency and location of flange are two crucial design objectives. For variable cross-section amplitude transformer design, the traditional theory calculation seems to be too verbose and sometime hard to get efficient solution. This paper focuses on using commercial FEM software-ANSYS to achieve an optimal design of amplitude transformer.