Applied Mechanics and Materials Vols. 130-134

Abstract: A new low cost microfluidic device has been designed and fabricated. Three thread microchannels were fabricated using tape and three indicting filter papers were also made by dipping three filter papers into sodium nitrite with different concentration. The side of the thread microchannels was connected to the indicting filter papers and then mounted on a 128⁰ yx-LiNbO₃ piezoelectric substrate, on which an interdigital transducer and reflector were fabricated using microeletric technology. PDMS film was coated to avoid the evaporation of microfluid transporting in the thread based microchannels. When a 25.5MHz RF signal with 25.4dBm power was applied on the IDT, the microfluid on the piezoelectric substrate was actuated by surface acoustic wave and transported along the thread microchannels, and reacted with nitrite ion in the indicting filter paper. Experimental results show that the thread-piezoelectric substrate microfluidic device can be used for biological or chemical analysis.

Abstract: This paper presented the elementary principle and the computation for waveguide eigenvalues by using mixed method (Quadric-FE-BEM). A general computer program based on the mixed method is programed, as an application, the cut–off wavelength of higher order modes in the rectangular waveguide are computed and the calculation results are well in agreement with the theoretical value. It has been shown that the mixed method is an effective method to analyze waveguide eigenvalues in engineering. At last, the cut-off wavelength of higher order modes in TEM Cell of homogeneous dielectric is also analyzed.

Abstract: For power distribution between engines and electric motors and the dynamic battery management SOC of the dynamic battery in HEV is an important parameter. To estimate SOC accurately LiFePO₄ Battery was taken as study object in this paper and based on the characteristic experiments of the LiFePO₄ Battery a new combining algorithm of estimating SOC has been put forward which combined Ah counting method, equivalent circuit model and open circuit voltage method. The simulation model of SOC algorithm in MATLAB was created in the paper and the results of simulation have indicated that the new strategy of estimating SOC was feasible and accurate.

Abstract: The thin films of W-doped VO₂ were synthesized onto Mo substrates using reactive DC and RF magnetic co-sputtering deposition techniques. The effects of W dopant on the semiconductor to metal phase transition of bare VO₂ were investigated with measuring X-ray diffraction (XRD) , QJ31Wheatstone Bridge and the internal friction and modulus vs temperature. The transition temperatures of VO₂ thin film from monoclinic semiconductor to tetragonal metal are decreased from 68°C to 40°C with the curves of resistance vs temperature and modulus vs temperature. In addition to, the size of grains W-doped VO₂ is more than that of un-doped VO₂, but more smoother.

Abstract: The index system of communication EW equipment`s Reliability can be qualitative and quantitative and multi-hierarchic.The method is used to evaluate communication EW equipment`s Reliability, which combines EAHP and fuzzy synthetic evaluation. Examples indicate that the method is feasible.

Abstract: This paper presents recent results of an experimental investigation on Deflagration to Detonation Transition (DDT) with H₂/air and C₂H₂/air mixtures in 60mm×60mm square detonation tube. The entire process of DDT is demonstrated by cellular patterns and the analysis is mainly based on their evolution.The pressure transducers and ion-probes were utilized to get the pressure and flame history in the tube respectively, and the corresponding cellular patterns are recorded on soot foils along cover board with 60mm×1380mm.Results show that overdriven detonation appears only once and several blast appear in DDT.Cellular patterns show that several twistable lines appear at the obstacle exit neighborhood area , while regular cell takes place after the final twistable line.Details of the cellular pattern indicate that from the early stage to the end of regular cell, the detonation wave sequentially experiences impactive area, abundant secondary cells, secondary cells expanding, local explosive, fine secondary cells, regular cell.

Abstract: A kind of control system which consists of high performance ARM microprocessor and embedded real-time operate system is put forward and researcheed. The control object and the requirements of system are analyzed; the general design project is determined; the control arithmetic and software structure are introduced in the end. ARM microprocessor is the intelligent core of the system. Matched with μCOS-II RTOS and application program, the system can complete the functions of information collection and real-time control.

Abstract: When friction pair contact with each other, self-generated voltage is a macroscopic potential difference manifested in the face of friction pair as a result of the interaction of diversified factor. It is consisted of contact potential between two different materials, thermal electromotive force in the friction process between two different materials, potential difference created by charge change in the contact and abruption process of friction pair and potential difference created by material transfer in the friction process. Self-generated voltage is measured in the paper through measuring system, and then the relation between self-generated voltage and frictional characteristic is analyzed. It is concluded useful to study observation and diagnosis of equipment friction with self-generated voltage signal of metal friction pair.

Abstract: With the continuous development of aviation technology, reliability requirements for air power is growing. As an important component, air static inverter air power has been studied extensively. In this paper, we study the following about the design of the front push-pull forward converter of Aeronautical Static Inverter: First, we design the Push-Pull Forward DC/DC converter control system on the basis of small-signal modeling; Secondly set control system parameters ; Finally, Through the simulation in MATLAB Simulink, we verify the design of the converter control parameter is reasonable, and then verify that Double-loop push-pull Forward DC/DC converter control system in the aviation static inverter is effectiveness.

Abstract: A continuous light-emitting laser diode power supply has been present,in this paper. The power supply is up to 50 W and the current is continuous adjustable below 5A . The supply is easy controlled, miniaturization, high efficiency, non-impact and slow-start to meet the characteristics of laser diode. The efficiency of the supply is better then 93% by application test.