Applied Mechanics and Materials Vols. 713-715

Abstract: Gas emission happens after coal and gas outburst, and it could cause secondary disasters in the roadway. Therefore it is necessary to research gas concentration distribution law in the roadway after coal and gas outburst, and theoretical basis for avoiding the occurrence of secondary disasters could be provided. Based on the above, Fluent is used to simulate gas concentration distribution law in the roadway during outburst. The research results show that gas velocity of the initial stage is larger in the whole process of gas outburst and gas emission impacts opposite walls in the form of jet in the roadway intersection. The flow changes direction and moves along the main airway and return airway. It produces countercurrent along the main airway. Because the pressure in the main airway is high, gas migration velocity becomes zero after a certain distance and is "back" to return airway. The higher the outburst velocity is, the longer the flow length is. Gas concentration variation with two kinds of different outburst intensities and position are regressed and it shows that correlation coefficients of power function are the highest. The research results have a certain theoretical value to prevent the occurrence of secondary disasters after coal and gas outburst.

Abstract: For the question of difficult to control discharge process between the electrodes in WEDM, Systematic analysis of the relationship breakdown and the distance between poles、the relationship of the breakdown voltage and pulse duration、the relationship breakdown and impurity、the relationship breakdown and the temperature、Summed up the WEDM in the general laws of the electrode gap breakdown、So as to better control of WEDM process in the very room provides a theoretical basis for discharge.

Abstract: EHD micro-jet can deposit rule and functional patterns in a direct, continuous and controllable manner, and has the advantages of good compatibility, high resolution and simple structure, thus becoming a cost-effective and high-efficiency technology. Through numerical method, obtain the three dimensional model of cone-jet and emphasize the correlation of sediment diameter and PEO concentration. The theoretical graphics agree well with the experimental data, which can explain and provide some theoretical basis for the experiments.

Abstract: Late exhaust duct EGR strategy is one of internal EGR strategies to realize HCCI combustion. Based on a single-cylinder test engine system equipped with an electronic controlled hydraulic variable valve train system, the effects of valve phases in this strategy were studied. The results show that at engine speed 1000r/min, equivalent air-fuel ratio λ= 1, when the IVO phase is put off, EGR ratio increases gradually, CA10 and CA50 are postponed and combustion duration becomes longer. At the same time, peak pressure and maximum pressure rise rate have a tendency to descend. When the SEVO phase is postponed, the parameters of the test engine will also be affected. However, when the phase is postponed above the critical point, the parameters have a backward trend. The property of HCCI combustion is not sensitive to SEVO phase.

Abstract: Aim at solving the electricity customer unclear ownership problems in some old city area, the transformer region customer information detection system was designed, using low voltage power line carrier (PLC) technology to detect transformer of the connectivity of concentrator and the collector within their respective jurisdictions, and further determined the dependencies of the electric power customer and concentrator, displayed results in the information management server. The system consists of the customer information detection terminal and the customer information management software. The experimental results show that the system can actually solve the issues of mixed customer information under the complex line loss problem.

Abstract: The electric-field, caused by corrosion and prevention of corrosion method was used to overcome the deficiency for acoustic detection system in underwater target detection. The research on electric-field detection was based on electric-field sensor linear array and digital signal processing technology. Firstly, the electric-field distribution feature was simulated by electric-dipole model in shallow sea. The electric-field sensor vertical line arrays were laid regularly to obtain electric-field signal. Then, the generalized likelihood ratio (GLRT) method was used to process target detection and parameter estimation. Finally, the simulation experiment was done and indicated that the method could accurately realize parameter estimation on target initial position, velocity and direction, etc all when the signal-to-noise ratio (SNR) was greater than 0dB. The error became larger as the SNR reduced. The GLRT still could detect target when the SNR reduced to-10dB and partial parameter estimation error became larger.

Abstract: The principle of Z-scan and its application on nonlinear refractive index and absorption coefficient measurement are introduced. Besides, two methods of improving sensitivity of Z-scan are described.

Abstract: Defective products are unavoidable in printed circuit board production process, so rapid detection and identificationmethods are badly in need of. PCB surface defect detection including a series of processing such as surface imagecapture, mixed noise filtering,images registering and so on, so it takes a lot of CPU time. To improve detection speed, based on GPU parallel computing platform, we designed a reasonable parallel processing system for PCB defect detectionto meet the need of real-time requirements of a production line. Experimental results show that parallel image processing algorithms based on GPU can achieve good results compared to the CPU-based serial algorithm (with speed up ratio up to8.34 in this paper),providing a new approachfor rapid detection of PCB surface defect.

Abstract: This paper briefly recommends the conception and syntax construction of the expert system language – CLIPS. Aim at fault happening mode, the paper build up fault analysis model of certain self-propelled gun servo system with CLIPS, compiled knowledge base and reasoning engine, realized embedded programming of CLIPS, and illuminated the application of CLIPS in fault diagnosis of self-propelled gun servo system.

Abstract: Introduce a kind of STC89C52 to control the core motion rod body measurement system, the system can be measured the movement of the length of the bar body, a number were detected, calculate the cumulative length of the rod body of the. The system comprises a data acquisition unit, a calculation processing unit, voice broadcast unit, LCD display and keyboard operation unit etc. The system has achieved good results in actual measurement, after the actual test device, this system can realize forward, fast, accurate measurement, it has very good practicality.