Advanced Materials Research Vol. 462

Abstract: For chaotic behavior appearances in Josephson junction of resistance-capacitor-inductor driven by the direct-current and in order to eliminate lateral oscillations of Josephson junction and dispel their adverse effect on the system performance or the working conditions of the system, the chaotic system of Josephson junction was analised. First, the complex dynamic characteristics of chaos were gave, including the phase trajectory map, Lyapunov index, bifurcation diagram. It proved the objective existence of chaos and the parameter range of the chaotic occurrence in Josephson junction system through the analysis of these characteristics. In order to eliminate chaos of the system, a new controller was designed, which contains only one controller term.. And it can control the system stability at the equilibrium point O(0,0,0). The results show that this method is effective, and constructing controller is simple, and the system after controlled has shorter dynamic response time and good robustness.

Abstract: The smelting process of fused magnesium furnace is a huge energy consuming process with nonlinear, current coupling and boundary conditions fluctuation. The smelting process stability is guaranteed by adjusting the three-phase electrode currents to achieve the control objective. In the past, the adjustment of electrode currents are manual control completely and the control effect is very poor, the currents fluctuation is very huge which lead to the instability of the product quality and great energy waste. As such, an intelligent control system is developed for fused magnesium furnace based on neural network (NN) algorithms and rule-based reasoning (RBR). The control objective for system is to reduce the energy consumption as much as possible under the constraint of insuring the product quality. The industrial application shows the validity and effectiveness of the proposed system.

Abstract: Advances in IP-based multimedia applications, coupled with the evolution of wireless networks results in a need for effective multimedia transmission and delivery of real-time content such as voice and video streams. Multicast has the potential to optimize network performance and support scalable distributed applications without compromising performance, efficiency, and QoS but introduces new challenges to transmit multicast packet in the backbone especially when incorporated into wireless mesh network with limited bandwidth. We propose ROHC enabled tunnel for source specific multicast architecture that will compress packet header and aggregate them to together in a frame to save bandwidth and address the packet loss. Our ROHC enabled tunneling protocol will act as SSM channel (S, G) and is designed to be deployed in the backbone network. In this paper, we analyze and discuss the how to address the bandwidth efficiency and packet loss with respect to our proposed tunneling protocol.

Abstract: The use of machine vision technology in the welding process has been developed along with the need for more consistent and more qualified welding results. The application of machine vision to perform object analysis without direct contact to the object itself making the whole processes fast while maintaining the accuracy. In this study, some image processing algorithms are combined which include : image enhacement (grayscaling and median filtering), edge detection, binarization, and Hough Transform for line detection. The candidate of welding tracks are produced through this standard algorithm. However, afterward, some modifications to the Hough transforms are carried to enable finding the actual welding tracks. The implemented method is capable of detecting the actual welding tracks and their appropriate welding path with accuracy not more than 0.9 mm.

Abstract: This paper theoretically analyzes the principle of the direct torque control method, then builds the direct torque control scheme of electric multiple-units(EMU) running during all speed range: indirect torque control in low velocity zone, eighteen polygon flux control method in moderate velocity zone and weakening hexagonal flux control strategy in high velocity zone. Simulation results show that the EMU direct torque control strategy in all speed range is feasible, and the system has good dynamic and static performance. All of the researches are available in the EMU controller research.

Abstract: The super high voltage generator, the stator winding of which is made of high voltage power cable, can be connected to the power grid directly. In this paper, the first super high voltage generator prototype at home is taken as an example, the equivalent circuits of the super high voltage generator system is proposed from the static power characteristic when the system transmission line is broke down because of the single phase to ground fault, phase to phase fault and two phases to ground fault. And the power expressions are also presented, and then the power angle and speed of the super high voltage cable wound generator are simulated with the improved Euler algorithm, and the critical fault clearing times of three faults are obtained. At the same time, the critical fault clearing time of a typical conventional synchronous generator system is also calculated and compared with the super high voltage cable wound generator system, and it is found that the dynamic stability margin of the super high voltage cable wound generator system is higher than that of conventional generator system.

Abstract: A remote finite element optimization system for key parts of large scale plastic mold is described. The functions of the system are realized using ASP.NET, SQL Server database and ANSYS optimum design. The parameters of geometry, material, load, and optimization are input on the web page. The system can query material properties of the mold, such as modulus of elasticity and Poisson's ratio from the material parameters query system. The key parts of the large scale plastic mold are modeled parametrically by the ANSYS Parametric Design Language (APDL). The codes of parametric modeling are encapsulated on the server. The parametric model reads and optimizes these parameters by the remote server. The optimum result could be browsed on the web page. The system lowers the demands of the relative knowledge about ANSYS which the designer should have.