Applied Mechanics and Materials Vols. 303-306

Abstract: Node localization is a key technology of wireless sensor network applications. Considering the resource constraints of senor nodes, node localization is transformed into an unconstrained optimization problem, then one distributed localization algorithm based on particle swarm with adaptive inertia weight is put forward. The unknown nodes construct particle region using the received information of their neighbor anchor nodes, which can reduce the search scope and save the computational cost of the algorithm. Mean deviation of the distances which are the particles to the global optima can be computed to characterize the distribution of particles, and is used to adaptively adjust the inertia weight to avoid falling into the local optima. Simulation shows that the proposed algorithm has a good localization performance.

Abstract: Severe temperature changes on electrical devices which are used ferrite cores causes very little degradation inside the core. In this paper was done to find out the size of the piezoelectric vibrator size and the most appropriate frequency In order to detect the degradation characteristics of the ferrite core. In this experiment, the frequency was used 1MHz,2.35MHz,5MHz, and the vibrator size was used 0.25inch,0.375incn,0.5inch. And the time axis variation was measured.

Abstract: The goal of this paper is to present a method for object tracking and positioning based on stereo vision in real time. The method effectively combined stereo matching algorithm with object tracking algorithm, and calculated the spatial location information of the object by using binocular stereo vision while the object is being tracked. The stereo matching used dynamic programming, image pyramids and control points modification algorithm, and the object tracking mainly utilized CamShift algorithm in this paper. The experimental results have confirmed that the proposed method realized real-time tracking for moving object, accurate calculating for the object three-dimensional coordinates, which meet the applied needs of servo follow-up system.

Abstract: Wheeled mobile platform is a common structure of mobile robots and electric vehicles. If the wheels driven by individual motors can be accurately controlled, the mechanical construction will be simplified and the composed movement would be precise. The high accuracy tachometric control is based on precise measurement of each driving wheel’s speed. And the mobile platform introduced in this paper has simple structure with light weight and fast dynamic response. Therefore, the digital control cycle should not be long. When the wheels are traveling at a low speed and the sampling period is short, the measurement error would be great, using the traditional methods. We adopted multi-microprocessor and external circuit as the hardware, and chose equal precision method to measure the rotational speed. The results show that this system has achieved high accuracy measurement with errors within ±1‰, which would secure the latter precise control.

Abstract: In this paper, we present a novel embed fluorescence method that allows one to monitor the change from emulsion polymerization to microemulsion polymerization with low monomer contents. The microemulsion polymerization of methyl methacrylate (MMA) was investigated using N-(2-anthracene) methacrylamide (AnMA) as the probe whose fluorescence emission intensity was proportional to the conversion of MMA into the polymer.In this research, the trace amount of AnMA unit looked like embed in the MMA chain. In a solution containing 3wt% of MMA with respect to water, with the anionic surfactant of sodium dodecyl sulphate (SDS) and water-soluble initiator of potassium persulfate (KPS), the process of changing from emulsion to microemulsion has been monitored. By contrast, with the non-ionic surfactant of polyoxyethylene (20) oleyl ether (Brij98) or water-insoluble initiator of 2,2′-azobis(isobutyronitrile) (AIBN), the process of changing from emulsion to microemulsion also have been monitored.

Abstract: With electronic transformers gradually being launched on the market, there is still no unified standard for electronic transformer calibration in China. According to this situation, two methods for electronic transformer calibration, the direct method and the difference method, were studied in this paper. Based on the virtual instrument technology, a novel electronic transformer calibrator compatible with both the direct method and the difference method was designed. This system is able to meet the calibration needs for electronic transformers with digital output and analog output at the same time. While using the spectrum leakage compensation algorithm, the calibration accuracy of this system is also enhanced.

Abstract: Interferometry is a very important method in high accuracy measurement for optical system. This article briefly introduced the conception of interferometry and took a product of 4D Technology as an example to carry on the measurement. A large-scale optic-electrical Theodolite in assemblage was measured, and its primary mirror was 400mm in diameter. With the analysis of the results, some micro adjustments of the mechanical structure proceed, and it made the system perform better. The final results of the whole system is 1.061λ in P-V value and 0.1136λ in RMS value (λ=632.8nm), this meets the demand of optical design and practical application. The result demonstrates that interferometry is a good way to be utilized and optimize in the procedure of assemble.

Abstract: On laboratory conditions，background leakage caused by temperature change was one of the most important factors for affecting calibration of pressure leak, consequently, the constant temperature water bath of the calibration apparatus has been used to reduce background leakage by means of keeping the apparatus temperature constant. The method of active and passiveness were combined to keep constant temperature. through the research on experimentation, it was found that background leakage was decreased to the grade of 1.36×10-9Pam3/s when constant temperature been used, and meanwhile the lower limiting of pressure leak was extended to 2.667×10-8Pam3/s.

Abstract: The measurement of the centroid position of small-scale focal spot is one of the most promising technologies for small-scale focal spot precise positioning. In this report, a method of two-dimensional scanning with CCD has been conducted to measure the centroid position and the intensity distribution of the small-scale focal spot. The theoretical analysis results are given.

Abstract: This Research was based on domestic and international pressure leak calibration technology, respectively, constant volume method and constant pressure(two model: saw-tooth variation constant pressure measurement mode and digital PID measurement mode) were both used on identical pressure leak calibration, 10-6 Pa•m3/s level, then, measurement uncertainty analysis of each method and the calibration results were compared.