Key Engineering Materials Vols. 467-469

Abstract: Fe-based amorphous coatings have many excellent performances, such as good corrosion resistance, high hardness, satisfactory magnetism, etc. In this paper, Fe-P amorphous coatings were prepared by electrodeposition method, and the phase transformation, microstructure, and hardness of the coatings heated at different heat-treatment temperature were investigated. The results show that Fe-P amorphous coatings begin to crystallize when heated at 300°C, the α-Fe(P) solid solution appears when heated at 330°C, and FexP(X=1,2,3) compounds separate out from the solid solution when heat-treatment temperature is up to 370°C. During the process of heat-treatment, hardness of the Fe-P coating increases as the reinforcement result of solid solution and dispersed phase in the coatings, and the hardness reaches the maximum 1100 HV at 370°C. When heat-treatment temperature is higher than 460°C, dispersed phase in the coatings will grow up, which is called Ostwald Coarsening Phenomenon, and hardness of the coating decreases quickly.

Abstract: The structure of chemical sensor has great influence on the performance of the sensor. This article studies on the relationship between the structure parameter and the mechanical characteristics of the sensor. The original resonance frequency and modes shape of the structure are obtained by the finite element analysis. Then a series of simulation comparison analyses are carried out to verify that the performance of modified sensor structure for food safety detection is improved greatly, which provides a good guide for the design of MEMS chemical sensor further.

Abstract: Micro-actuator is the key device for the MEMS to perform physical functions. According to a kind of bimorph thermal actuator, this article presents an optimum design method to improve the sensitivity of MEMS actuator. Based on thermal analysis of software ANSYS, the thermal displacement and distribution of temperature field can be obtained clearly. Then a series of reasonable parameters are determined by optimum calculation. The simulation comparison analyses including thermal displacement, stress distribution and fatigue life are carried out to demonstrate that the sensitivity of the optimized structure has been improved effectively by the presented optimization method.

Abstract: Coupled system of two second order ordinary differential equations with small parameter was considered. This is a multi-scale system. The solution of the system will change rapidly near both sides of the boundary layer. The system was decomposed into several systems in order to have fourth order asymptotic decomposition firstly. The asymptotic properties of all these systems were discussed secondly. The third order numerical methods were constructed for left side and right side singular component systems thirdly. The error estimation for the system was given finally.

Abstract: Ordinary differential equation with periodical boundary value and small parameter multiplied in the highest derivative was considered. The solution of the problem has boundary layers, which is thin region in the neighborhood of the boundary of the domain. Firstly, the properties of boundary layer were discussed. The solution was decomposed into the smooth component and the singular component. The derivatives of the smooth component and the singular component were estimated. Secondly, mesh partition techniques were presented according to one transition point method and multi-transition points method. Thirdly numerical methods based on non-equidistant mesh partition were presented to solve the problem. Finally error estimations were given for both computational methods.

Abstract: To enhance the work efficiency and systematization degree of fault diagnosis for process production, an extension CBR fault diagnosis (ECFD) method is proposed in which the extension theory applies the formal model to expand the possibility of matter and explore the innovative principle, and the CBR technology provides the ways for solution based on the historical experiences. Considering the characters of the two technologies, some researches are made on the extension basic-element case-description, distance-based extension case-retrieval, and character difference-based extension case-revision for fault diagnosis. Taking the purified terephthalic acid (PTA) solvent system as an application example for fault diagnosis, the ECFD method is proved to be feasible and effective, which provides a new way for diagnosing the production faults accurately.

Abstract: Based on research of the Infrared Heating Oven, an important equipment of the zinc plating production line, the paper established the mathematical model using the principle of heat transfer, and analyzed main influencing factors such as thickness, width, speed of the strip and characteristic parameters of the coating. Both the steady and unsteady-state heat conduction are considered, which provide more accurate theory basis for the design and use of infrared heating oven. And through the theoretical derivation, the relationship between input voltage and output power was made out, which will better fulfill the convenient control.

Abstract: The forward displacement analysis of parallel mechanism is attributed to find the solutions of complicated nonlinear equations and it is a very difficult process. Taking chaotic sequences as the initial values of Newton-downhill method, we can find all the solutions of equations quickly. Making use of existing chaos system and discovering new chaos system to generate chaotic sequences with good properties is the key to the Newton-downhill method based on Chaos sequences. Based on utilizing hyper-chaotic Hénon mapping to obtain initial points, a new method of finding all real number solutions of the nonlinear questions is proposed. Using cosine matrix method, the author established the mathematical model of forward displacement for the generalized 3SPS-3CCS parallel robot mechanism and a numerical example is given. Compared to the quaternion method building mathematical model, the result shows cosine matrix method building mathematical model and hyper-chaotic Newton-downhill method finding solution is brief and high calculation efficiency as the calculation is done in real number range. The proposed method has universality which can be used in forward displacement of other parallel mechanism.

Abstract: Newton iterative method is an important technique to one dimensional and multidimensional variables and iterative process exhibits sensitive dependence on initial guess point. The property of chaos serials produced by Lorenz chaos mapping method was analyzed. For the first time, a new method to find all solutions based on utilizing Lorenz chaos mapping to obtain locate initial points to find all solutions of the nonlinear questions was proposed. The numerical examples in linkage synthesis and approximate synthesis show that the new method is correct and effective.

Abstract: Many questions in natural science and engineering are transformed into nonlinear equations to be found, Newton iterative method is an important technique to one dimensional and multidimensional variables and iterative process exhibits sensitive dependence on initial guess point. The property of chaos serials produced by Sinai chaos mapping method was analyzed. For the first time, a new method to find all solutions based on utilizing Sinai chaos mapping to obtain locate initial points to find all solutions of the nonlinear questions was proposed. The numerical examples in linkage synthesis and approximate synthesis show that the new method is correct and effective.