Advanced Materials Research Vols. 1030-1032

Abstract: The merits of HVDC,such as long-distance power transmission, less line lose,ability to transmit high-power and so on,were introduced. The obstacles in development of HVDC,including failure of commutation,hazards of higher harmonics,limitations of transmission direction, problems of insulation and so on,were analyzed. The research progress both at home and abroad in development of HVDC were summarized.At last,research and application prospects of HVDC were prospected briefly.

Abstract: Rocket engine thrust is the main performance parameters. The flow field of missile fight in different Mach is simulated by using FLUENT, then calculating the thrust of different conditions. The calculating results are consistent with the theory of Mach almost no effect on the thrust.

Abstract: In this paper a computer modeling using program complex DEFORM of various models of equal channel angle pressing is made. Also there is a description of opinion of ECA-pressing called “ECA pressing with quasi-ultra-small angles of joint channels” and shown advantages of this opinion.

Abstract: In order to make good use of the previous design knowledge, the knowledge-based engineering ideas were introduced to the design of airfoils for variable-pitch wind turbines, a new design method for airfoil of wind turbine was formed. Firstly, the structure-behavior-function (SBF) model of airfoils design was derived. Secondly, the neural rules for airfoils design of variable-pitch wind turbines were deduced. Thirdly, the design method of airfoils structure for wind turbines based on case-based-reasoning (CBR) was establishment. And the dimensionless model based on case representation was set up, and the algorithm of geometric parameters design for airfoils based on CBR was proposed at last.

Abstract: In this paper, a kind of amplifying and shaping circuit was designed according to the characteristics of high frequency and small amplitude of surface acoustic wave (SAW) gas sensor signal. The circuit is applied to two-channel mixing detection method to solve the problem that backend devices cannot identify sensor signal. The whole circuit is simple in structure and has very good shaping effect on voltages signal of millivolt level, meeting the need of the sensor of gas detection.

Abstract: The paper presented the gas flow field and particle trajectory with a series of inner cylinders in cyclone preheater using RNG k-ε turbulence model and stochastic trajectory model on the platform of Fluent software. The separability and pressure loss of cyclone preheater were investigated. The result shows the ratio of d/D and h/H of cyclone preheater was advised 0.50 to 0.65 and 0.35 to 0.60 respectively. It is also found that the numerical simulation results are in agreement with the thermal data of cement plant.

Abstract: Because difference of formation model affects the potential distribution on the metal casing, the resistivity logging response can be obtained through casing by measuring the potentials on the metal casing. In fact, the logging responses are the comprehension effects of complex formation and metal casing, so that in the coefficients of transmission line equation (TLE), we should consider the effects of formation model in radial-direction. In the following, for the formation taking on six-layer in axial-direction, and step in radial-direction, the resistivity logging responses through casing are researched and discussed, and given the recurrence formula to compute potential. Draw the curve of the resistivity logging response through casing of six-layer formations. The conductivity of formation is computed is very approximating to that of formation model. The computing examples also show that this method has a fast computing speed (the run time of computing example is less than 1s). For analysis the logging response of six-layers and block formations, and the design of logging instruments, the research is important significance and useful.

Abstract: Small current grounding power system is widely used in overhead transmission line in medium voltage distribution network in China. Because of its long lines, branch, space truss structure is complex, low level of automation, It is easily influenced by outside force and the natural environment, and single-phase grounding failure rate is high. It is an important topic to quickly and accurately detect the location of the fault line, and improve the reliability of power supply and distribution system.This paper has carried on the induction and the comparison of various fault detection and location method of overhead transmission line which is currently used in single phase to ground, and analyzed their advantages and disadvantages,given the corresponding conclusions, provided the reference for finding out the reasonable single-phase earth fault location method or improvement.

Abstract: As an important type of energy reserves, underground gas storages are increasingly being used in China. XX salt cavern gas storage provides many experiences as the first one in China. In this paper, the surface gathering system process in XX gas storage was studied systematically. And also, the optimization to separator, pressure regulating device, flow meter in single well process were also made according to the field operation and theory. Through the optimization, the single-well process will be more simple and easier to maintain, and the leftover problems were also resolved, which provided advice to the later stages of XX gas storage.

Abstract: Cadmium zinc telluride (CZT) material is one of the preferred materials for the fabrication of X-ray and gamma-ray detector. In this paper, it is presented a room-temperature nuclear radiation detector system based on CZT material with planar electrode and ohmic-contact. The experimental validation and analysis of the designed system is carried out. At the same time, some research and design on the surface signal-readout method、the charge sensitive preamplifier circuit、pulse signal processing circuit and soft processing program is made. The signal from the CZT material exposed to the radiation through the experiment is successfully required. The signal from the experiment is correspondingly processed and validated. The potential factors that influence the detector performance are discussed. The conductive adhesive is the joint of the ohmic-contact electrode and the preamplifier circuitry. The preamplifier circuitry has high gain, rise time in the nanosecond level and little equivalent charge-noise. The research and experimental design base for the development of subsequent gamma spectrometer.