Applied Mechanics and Materials Vols. 687-691

Abstract: Within the quasi-one-dimensional effective potential model and effective mass approximation, we calculate the ground and the first few excited state binding energies of a donor impurity in a rectangular quantum dot (RQD) in the presence of electric field. We discuss detailedly dependence of the binding energies on the impurity positions. The results show that the binding energy is the largest when the impurity is located at the center of RQD with zero field and is lowest when the impurity is located at the corner of the RQD. The peak strengths and positions of the probability density in RQD appear to be the critical control on such impurity-induced dependence. We believe our results can provide an indication for design of some photoelectric devices constructed based on GaAs RQD structures.

Abstract: Electrified railway traction transformer is a pivot that connects the electric locomotive and the public grid. Therefore, power quality problems caused by electric locomotive such as three-phase voltage imbalance, great voltage fluctuation and high harmonic content can be transmitted to the public grid via the traction transformer. To solve this problem, the solution of two sets of single-phase SVG (Static Var Generator) in back-to-back operation to solve power quality problems of the electrified railway is raised. This solution has been proved by practice effective in improving power quality of the traction transformer.

Abstract: This paper mainly presents the common malfunction analysis and maintenance of computer motherboard interface. First introduced the mainboard interface simple maintenance of the basic knowledge, and then analyzed the frequent failures of maintenance. In the end, enumerates the maintenance examples to further understand maintenance knowledge.

Abstract: With the introduction of advanced information technology such as cloud computing, virtualization, we will solve the current and future IT construction difficulties. It can also be advantageous to improve the rational allocation of computing resources and improve the utilization rate through the application of this new type of resource organization, distribution and usage patterns. Finally it will promote energy conservation and emissions reduction, lift up green computing development.

Abstract: In this paper, according to the structure character of transmission tower, the transmission lines are simulated as link10 space spar elements which have the unique feature of a bilinear stiffness matrix resulting in a uniaxial tension-only (or compression-only) elements and the transmission tower are simulated as space element beam188 and link 8. So the ANSYS fine finite element models of transmission tower-line system which are more agrees with engineering practices are set up, dynamic characteristics are calculated on nine conditions and the influences of transmission line on dynamic characteristics of the transmission tower are discussed, some valuable conclusions are given.

Abstract: In this paper, a multi-channel large-capacity acquisition and storage system is prototyped to meet the urgent need of multi-channel analog signals’ acquisition and analysis. Composed of an acquisition board and storage board based on FPGA, the system could acquire 4 channel signals and store them in 512GB flash array. Gigabit Ethernet is used to connect the system and PC, which ensures high throughout between them. Ping-pong operation and pipeline technology are applied to cover the programming time of flash to improve the access speed. The system is portable, stable, and expansible, and could be used in various areas.

Abstract: Strip Layout design plays a key role in multi-station progressive die design, and the traditional method of designing layout is complicated, timewasting. To design layout of progressive die with PDW is efficient, easy to be modified. In this paper, the process of building layout is discussed. First of all, sheet metal should be pretreated to build immediate stage, and the suitable method can be chosen to unfold sheet metal according the configuration feature of the product. Secondly, it needs to build the assembly structure of progressive die, called initialization. Thirdly, with tools including Blank Generator, Blank Layout, Scrap Design, and Strip Layout to finish layout design. In the end, the paper takes a sheet metal for instance to finish the layout. The method of designing layout with PDW improves the traditional method’s deficiencies, and improves the efficiency greatly.

Abstract: The paper adopts the TMS320DM8168 processor to realize highly resolution network video surveillance system, and selects highly efficient video coding standard—H.264 compression algorithm to enhance the efficiency of coding data. The system based on embedded Linux system and the TMS320DM8168 processor is put forward which can be operated on 8-megapixel.At 60 frames per second in full frame rates, It is the video stream up to 2Mbps rate to provide resolution of 1920x1080 pixels. The Three video streams can be transferred in the 1000M Ethernet applied with the real time transport protocol (RTP) and real time transport control protocol (RTCP).

Abstract: The accurate detection of lung sounds is the premise and infrastructure to achieve non-invasive diagnosis of cardiovascular disease, and the disease noninvasive diagnostic methods based on cardiovascular lung sounds have non-invasive, fast, convenient, and economic characteristics. According to this, the embedded acquisition system for lung sound signals is designed based on the STM32 microcontroller, Stethoscope and electrets microphone is adopted as the lung sound signal acquisition module. The experiment is done based on this system, and the result shows that this designed system working properly, and reliable design.

Abstract: The technology of VSC-HVDC transmission has a high degree of flexibility and controllability.This paper researches the control strategy of VSC-HVDC and the operating principle of the wind turbine, which can effectively enhance the stability of power system in the region of wind farms, improve the long-distance transmission capacity of wind power and stabilize the voltage level of public connection point.