Key Engineering Materials Vol. 503

Abstract: A novel preconcentration method for efficient DNA sample stacking during sample introduction and injection in microchip electrophoresis is presented in this paper. The method suggests that a pair of sample stacking electrodes is designed after the double-T section. A sample stacking electrical field can be established after sample introduction inside the double-T section, so that the sample stacking procedure can be controlled accurately and efficiently. In order to test this method’s validity, a numerical model is setup using COMSOL Multiphysics software. The simulation result shows that the peak DNA concentration can be increased up to 10 fold by this method. These results demonstrate the great potential for significantly enhance DNA sequencing speed and resolution in microchip electrophoresis.

Abstract: Micro injection molding is used widely owing to its high accuracy, high production efficiency, low cost and can fabricate products with complex structures. For optical components, the residual stress is a main element for quality. In this research, the light guide plate is used as the study object. The light guide plate was designed by software Pro-E, and was simulated by Moldflow for filling process. Orthogonal method was used in this research. The most important factor that affects residual stress level is mold temperature. The level of the different process parameters on residual stress are mold temperature, packing time, packing pressure and melt temperature.

Abstract: A MEMS broadband microstrip patch antenna based on Minkowski fractal boundary is designed. An air layer is designed in the antenna’s high resistance silicon substrate by MEMS technology and microstrip patch antenna with second degree iteration Minkowski fractal boundary is simulated. Then different p on the influence on the broadband performance of the antenna is discussed. The simulation results show that the broadband performance can be gained from microstrip patch antenna with MEMS air layer based on second iteration Minkowski fractal boundary. 23.34% relative bandwidth of the optimized antenna is achieved and the requirement of the broadband communication is satisfied.

Abstract: In this paper, the relations between scattering intensity and the radius of scattering particles, the refractive and the wavelength have been studied based on the MATLAB software, and the relations between the concentration of the particles, the radius and the refractive and the optical properties of diffuser have also been simulated by the Light Tools software based on the Monte-Carlo Method. The results show that with the increasing of radius and the wavelength, the distribution of scattering light energy gets concentrated. With the increasing of the particles, the transmittance decreases, and the uniformity increases first and decreases later. With the increasing of radius, the transmittance decreases. With the increasing of the index of refractive, the transmittance increases first and decreases later.

Abstract: This paper presents a complete set of SIMULINK models, which allow exhaustive behavioral simulations of fluxgate system to be performed. The model construction is detailed and it is applied to the Vacquier-type fluxgate sensor. Well known characteristics of these sensors are confirmed through the simulations. In spite of this simplicity, the model has been successfully used to describe the variation of the output of a Vacquier-type fluxgate sensor with the amplitude and the frequency of the driving current. Using a previously developed 2nd harmonic fluxgate magnetometer, some preliminary experimental results are obtained confirming the appearance at its output.

Abstract: This paper presents a new way to design a low-cost micro-thermoelectric generator (μ-TEG) which can be fabricated by using electrochemical and MEMS technology. The overall dimension of the μ-TEG is about 13mm × 13mm × 0.4mm, which contains 128 p- and n-type pairs of semiconductors connected electrically in series and thermally in parallel. The p-type antimony telluride (Sb2Te3) and n-type bismuth telluride (Bi2Te3) with an optimal thickness of 20μm were designed to deposit in a flexible polymer mold formed by photolithographic patterning of Polyimide (PI) with a three electrode configuration. Simulations of the thermocouple with PI mold were carried on, using finite element analysis. The analysis shows the possibility to achieve 3.5 mV while the difference in temperature is 10K and the thickness of the silicon substrate is 400μm, which reveals that the output power of the thermocouple without releasing process is only 4% lower than the one with the releasing process. Therefore the PI mold is not removed, considering the potential for easier fabrication and lower cost. The deposition parameters were also studied and optimized for the best thermoelectric performance. In our experiments, the n- and p-type semiconductors could be obtained when the voltage and current are around 50mV versus saturated calomel electrode (SCE) and 40 mA, respectively.

Abstract: This paper describes the effects of the microsphere-taper coupling structure from the external libration Sound, especially the impact on the coupling distance. Here two solutions have been proposed. One approach is to cover the system with a insulation shield. The other is to integrate the coupling structure with the ultraviolet glue. The results show that both measures are viable. The packaged microsphere-taper coupling structure is entirety separated from the nonego, making the structure not be disturbed by the external libration sound. In the subsequent experimentation, the packaged structure will have a good prospect.

Abstract: This paper presents a portable phosphate detection system based on electrochemical reaction mechanism using cobalt modified microelectrodes. The microelectrodes were fabricated by MEMS (Micro-electromechanical Systems) technology and modified by electrodeposition of cobalt. The performances of the microsensors were characterized by testing a series of standard phosphate solution. MSP430F4793 microcontroller was applied to control the detection process at low power consumption. Comparing with the test results achieved by using traditional electrochemical workstation method, this portable detection system has similar characteristics with the concentration range from 10-6 to 10-4 mol/L.

Abstract: The diffusers with microlens arrays and V-cut micro structures of LED light were designed in this paper. Based on the theory of non-linear ray tracing, optical properties of the diffusers with three different micro structures were simulated by Lighttools. The three different structures are diffuser with non-structures, diffuser with 0.4mm in diameter microlens arrays and diffuser with V-cut which groove width is 0.4mm and the material of the diffusers was PP (polypropylene). Three types of diffusers were fabricated by extrusion rolling method and their transmittance and uniformity were tested. The simulation showed that diffuser with V-cut micro structures had the best transmittance and uniformity. The experiment showed that the diffusers produced by extrusion rolling method had perfect reprint effect. The simulation results and experiment results had much consistency in transmittance and uniformity. This research is helpful to solve the non-uniform luminescence and glare problems of the LED light.

Abstract: A refined approach producing MEMS numerical macromodels is proposed in this paper by generating the iterative Krylov subspace using a refined Arnoldi algorithm, which can reduce the degrees of freedom of the original system equations described by the state space method. Projection of the original system matrix onto the Krylov subspace which is spanned by a refined Arnoldi algorithm is still based on the transfer function moment matching principle. The idea of the iterative version is to expect that a new initial vector will contain more and more information on the required eigenvectors that is called refined vector. The refined approach improves approximation accuracy of the system matrix eigenvalues equivalent to a more accurate approximation to the poles of the system transfer function, obtaining a more accurate reduced-order model. The clamped beam model and the FOM model are reduced order by classical Arnoldi and refined Arnoldi algorithm in numerical experiments. From the computing result it is concluded that the refined Arnoldi algorithm based Krylov subspace technique for MEMS model order reduction has more accuracy and reaches lower order number of reduced order model than the classical Arnoldi process.