Advanced Materials Research Vols. 433-440

Abstract: The traditional 6-pulse high-power rectifier has defects such as large harmonic content and low power factor in application. The 24-pulse rectification system based on autotransformer can restrain the harmonics and improve power factor effectively. This paper derivate the input current and output voltage’s characteristics of 24-pulse rectification system under balanced grid. At the same time, the author simulate and analysis various impacts of different situations of unbalanced grid on these two characteristics on the basic of real grid ,which has an important guiding significance on the application of the 24-pulse rectification system.

Abstract: In this paper, a micro structural model is applied to study the normal contact process of the specimen of the ultrasonic feeding. Firstly, the normal velocity of the specimen with the actuation of the oscillator is calculated by solving the nonlinear dynamical equation of the specimen. The theoretical results of the normal velocity are in good agreement with the experimental results under the same conditions. The theoretical results indicate that for the low frequency of the oscillator, at most time, the normal contact force is zero, whereas for the high frequency the normal contact force is periodical. In addition, the theoretical results also indicate the contact time between specimen and the oscillator in a period decreases with the increasing amplitude of the oscillator.

Abstract: For the case of ship-air missile intercepting the low target beyond visual range by ship-ship coordination, the instruction solution model was presented and an optimal guidance law was designed considering the effect of the curvature of the earth. In the midcourse and terminal guidance segment, the optimal guidance law was designed through applying the concept of the pseudo control variable and the theory of the linear quadratic optimal control. The information of the target was described in the launch coordinates through coordinate transformation to realize the instruction solution for the designed guidance law. The simulation results show that the model of the instruction solution is correct and the designed guidance law is feasible.

Abstract: High-performance data acquisition system is designed on the foundation of studying the working principle of diesel engine fuel injection system and analyzing the characteristics of fuel injection pressure waveform. The fuel injection pressure waveform can be accurately captured by the data acquisition system which based on embedded pressure sensors and NI PXI-6143 multifunction data acquisition card, and then the fuel injection opening pressure and the maximum injection pressure can be calculated. Fuel supply advance angle can be obtained by comparing the injection pressure waveform and the top dead center signal. The signal to noise ratio of the data acquisition system is very high, and the operating parameters of fuel supply system can be calculated without software filter. The fuel injection opening pressure, maximum injection pressure and fuel supply advance angle were obtained in situ test on 6L20/27 diesel. The operating parameters all coincide with the technology data sheet given by the factory.

Abstract: Automatic transmission may produce busy shifting on uphill and downhill. This article analyzes three algorithms about the estimation of road ramp: the first using a longitudinal acceleration, the second using estimated output torque, and the third using the difference between two accelerations. The first method is more accurate than the other two, but it is more expensive because an additional acceleration sensor is needed. The second is more complicated and in some driving conditions, it could not estimate the output torque. The third is based on simple theory and inexpensive since no additional sensor is needed. Some simulation results of avoiding unnecessary gear-shifting are also presented in the paper.

Abstract: As users of the increasing demand for multimedia services, 3GPP long term evolution system proposed the Long Term Evolution, LTE. LTE is the most important improvements with a new air interface technology to provide users with higher peak rates. Accurate channel estimation is to ensure the transmission quality of LTE system and the key to its advantages. In pursuit of lower bit error rate (BER), this paper based on pilot signals TDD LTE system on the uplink channel estimation algorithm. Use LS algorithm, MMSE algorithm and svd algorithm. Based on these three improved svd algorithm, it gave the simulation results.

Abstract: 3201Z-type dump truck is modification desiged by EQ3208GJ dump truck chassis which the technical performance parameters are known, and using a lifting mechanism of air controlled hydraulic system. By analyzing the composition and working principle of air controlled hydraulic system and referring to similar models, the design of the tank, the limiting mechanism and power taker are conducted. By calculating the main technical parameters, including in the performances of the hydraulic cylinder and the hydraulic pump, the dump truck's special oil cylinder HG-E180X780 and gear pump CBT-E563 are selected. By the stability of the piston rod, the system pressure and cars lifting time are checked, the reasonability and safty of the design can be proved.

Abstract: Topology and its various benefits and functionality are fairly well understood within the context of 2D Geographical Information Systems. We summarize the principle of common 2D topology and the implementation of GIS databases. Existing topological frameworks and data models as a staring point to guide the review process, three key areas were studied for the purposes of requirements identification, namely existing 2D topological systems. However requirements in 3D have yet to be defined, with factors such as lack of familiarity with the potential of such functionality of 3D systems impeding this process. In this paper, we identify and review the requirements for topology in three-dimensional (3D) applications. Requirements for topological functionality in 3D were then grouped and categorized.

Abstract: Retracted article: The mode matching method is applied to analyze generalized ridged waveguides. The tangential fields in each region are expressed in terms of the product of several matrices, i.e., a functional matrix about x-F(x), a functional matrix about y-G(y) and a column vector of amplitudes. The boundary conditions are transformed into a set of linear equations by taking the inner products of each element of G(y) with weight functions. Two types of ridged waveguide are calculated to validate the theory. Several new modes not reported in previous analysis are presented.

Abstract: This paper aims to give the consumer a list of energy saving practices in order to reduce the usage of energy in residential and commercial buildings. Such practices are crucial to any residential or commercial setting before embarking on installing renewable energy systems such as solar power systems. Those methods are relatively cheap to implement and has the potential to provide energy savings up to 30 %.