Key Engineering Materials Vols. 474-476

Abstract: In this paper we consider the system of M/M/N queue with service interrup-tions , therates of server breakdown are different between busy time and idle time, and thereis one repairman ite system. We give out the group of equations for the steady state distribution of the number of effective servers. We obtain the steady-state probabilities of the states and the steady-state availability of the system. This document

Abstract: For the frame characteristics of leveler and the leveler AGC control system requirements, this paper analyzed the structure of the frame. And using the finite element software ANSYS analyzed the stress distribution and deformation of leveler prestressedstand. Thus we can obtain the frame stiffness in different preload coefficient, and establish the corresponding AGC compensation model. All of this, the leveler control system can provide the precise compensation for frame bounce. Because of this, it improved the straightening precision, and achieved the lean straightening. Meanwhile, it can provide the feedback guarantee for the accurate correction of leveler model.

Abstract: ZnO nanoparticles were synthesized in the method of precipitation, and they were characterized by the means of the transmission electron microscopy (TEM), the X-ray powder diffraction (XRD), the thermogravimetric analysis and differential thermal analysis (TG-DTA), and the Fourier transform infrared spectroscopy (FT-IR). Also their photocatalytic and degradation performance for the methyl orange aqueous solution were studied. The research results showed as-prepared ZnO nanoparticles were spherical crystals in hexagonal crystal system, and their size distribution was mainly in the range of 20-30 nm. The annealing temperature was about 390 °C, and a few organics remained, which may be helpful for the formation of ZnO particles. They had integrated crystal form, high crystallinity and thermal stability. Moreover, the obtained ZnO nanoparticles had excellent photocatalytic and degradation performance for the methyl orange aqueous solution. When reacted for 3.5 h, the degradation rate of the methyl orange aqueous solution was up to about 97%.

Abstract: With the development of computer technology, Computer Aided Engineering (CAE) and Computer Aided Inspection (CAI) are more widely used in stamping products for design and manufacture, but there is a lack of link between each other. On the one hand, results of CAE analysis are not effectively used and evaluated; the other hand, single CAI is not able to analyze reasons for wrinkle, crack, or springback in stamping products. To compensate these shortcomings, a CAE/CAI integrated method is established to ensure information sharing between of them, which is helpful for guiding the design of sheet metal forming. By this method, the feasibility of sheet metal forming is analyzed and forecasted, and the results of deformation are effectively assessed by 3D comparison, 2D comparison and GD&T inspection. And ultimately the superiority of CAE/CAI Integrated method is proved by case study.

Abstract: Blended-Wing-Body (BWB) civil aircraft possesses so light structure, high lift-drag ratio and low fuel burn that it has been an important topic of future civil aircraft. But internal pressure causes large bending stress instead of skin-membrane stress in BWB non-cylindrical fuselage. For 150 seats BWB fuselage, a composite 3-bay fuselage model is analyzed and two improved configurations of braced fuselage derivatives are designed in this paper. By optimization analysis, the optimized non-cylindrical fuselage structures are obtained in low bending stress and deformation condition, and optimized layer thicknesses ratio of composite material are presented. The optimization conclusions are very valuable and applicable for the fuselage structural design of BWB civil aircraft.

Abstract: In this paper, the single-phase synchronization inverter of fuel cell is taken as the main topic. The network system topology, the control strategy and the phase-locked algorithm are analyzed in detail. The system’s main circuit topology, the software PLL principles and process are proposed, and they are verified by the experiments.

Abstract: Mobile and wireless technologies (MWTs), such as wireless laptop computers, personal digital assistants (PDA), mobile phones, smart phones, etc., have been widely used in our lives. Government agencies are using MWTs to enhance their managerial effectiveness and provide convenient service to citizens. Based on fairness theory, this study develops a typology of the characteristics of MWTs in m-Government systems: transparency-related MWTs characteristics, information accuracy-related MWTs characteristics and voice-related MWTs characteristics, and examine how the three categories of MWTs characteristics affect user satisfaction in mobile government systems.

Abstract: In order to meet the requirements of high torque and small center distance of the twin screw pulping extruder, an improved design method of the crown gear coupling (CGC) was studied. Based on the preliminary structural design, the paper selected parameters of tooth form of the crown gear firstly, and according to the contact strength solved the tooth width, then the discussed influences of radius of displacement circle and unilateral thinning amount on tooth thickness, finally through the finite element analysis verified the design results. The results show that under the condition of radial restriction the most effective ways to increase load-bearing capability of the CGC are to improve the tooth stiffness and increase the tooth width, and the increasing of tooth width should consider the tip strength of the crown gear and avoid over-cutting. The CGC design method of the paper can meet the requirements of the twin screw extruder.

Abstract: The effect of sintering temperatures (1050-1200 °C) on the phase formation, microstructure and dielectric properties of a binary system lead-free ceramic bismuth sodium titanate–bismuth potassium titanate were investigated. 0.8Bi_0.5Na_0.5TiO₃-0.2Bi_0.5K_0.5TiO₃; BNKT ceramics were successfully fabricated using the combustion technique. XRD results showed the rhombohedral-tetragonal morphotropic phase boundary (MPB). The SEM results showed the average grain size (0.51-2.59 µm) of the samples increased with the increase of sintering temperatures. The sample sintered at the optimum temperature of 1150 °C exhibited the maximum density, shrinkage, dielectric constant at Curie temperature and remanent polarization (P_r) which were around 5.65 g/cm³, 17.75%, 5014 and 1.6 mC/cm², respectively. The dielectric constant was related to the XRD results and density of the sintered ceramic.

Abstract: In e-commerce platform, the auction market is the most attractive channel for the general public. Because of low cost, making the entry barriers are low. Online sellers rely on the auction website as the platform. However, “What sellers should do to maximize the profit” is the main purpose for this paper. This study used Apple ipod nano as an auction object on Yahoo!Auctions, and we came up with eleven factors as research variables , and tried to use genetic algorithm to build a successful auction model for sellers. In this research , if the results showed that the optimal seller behavior of chromosomes are 1,6,9,11 from the portfolio, it means that the seller need to provide product images, accept “Buy it now” , inform buyers about deliver time and maintain a good seller reputation. Therefore, the seller might be recommend to make efforts on the provision of product information, include pictures of auction goods and answer all detail questions, accept “Buy it now” , inform the buyers when sending out the goods, and maintain good reputation.