Papers by Keyword: Micro-Electromechanical System (MEMS)

Abstract: The artificial basilar membrane has been developed to mimic the mechanical performance of the basilar membrane in the cochlea. The artificial basilar membrane consists of an array of microbridgeresonators that are mechanically sensitive to the perceived audible frequency range between 20 Hz to 20 kHz. In this work, the finite element (FE) model of the microbridge resonators have been designed in Comsol Multiphysics 4.3 to work close to the audible frequency range. The lumped element (LE) model of the microbridge resonators have been calculated and compared to the simulated FE model. The microbridge resonators array with 0.5 μm thickness, 20 μm width and length varying from 275 μm up to 7700 μm have been designed using two different materials, i.e., platinum (Pt) and aluminium (Al). The microbridge resonators have been found to mimic closely the tonotopicorganisation characteristics of the basilar membrane. From the FE and LE models of the Pt and Almicrobridge resonators, Pt has been found to be a better material than Alfor the artificial basilar membrane design. For the same geometrical dimensions, the Ptmicrobridge resonatorsoperate within the audible frequency range while the Almicrobridge resonatorsoperate approximately 43%-53% above the audible frequency range.

Abstract: In order to realize consistency and low cost in the production process of the exploding foil initiator, the manufacturing method of exploding foil initiator was studied using micro processing technology. Microcrystalline glass was used as substrate, and magnetron sputtering,photolithography and wet etching technology were utilized to product the metal bridge foil on the surface of the substrate. SU-8 photoresist was used as the barrel material and scanning electron microscope was exploited to characterize structure of the initiator. Through the electrical tests, the flyer was successfully generated and after the barrel had a good integrity.

Abstract: In this paper, a novel microdevice-based solid phase extraction (SPE) method has been developed to extract genomic DNA from real biological samples, such as whole blood, by using a green reagent NaCl as the new binding salt. Guanidine as a bind salt was widely used for extraction DNA with a high extraction efficiency. But it was proved that guanidine was a kind of polymerase chain reaction (PCR) inhibitors, which is also toxic and the waste of guanidine might contaminate environment. NaCl is a natural, nontoxic, cheap, and green reagent, which would be a perfect candidate to replace guanidine. Silicon - polydimethylsiloxane (PDMS) - glass microdevice with a microchannel was designed and fabricated by micro electromechanical system (MEMS) technology. The DNA adsorption on the surface of the microchannel was observed by scan electron microscopy (SEM) technology. Then both NaCl and guanidine were used as the binding salt to extract genomic DNA from real biological sample. Compared with the binding salt of guanidine, the microdevice-based SPE method using NaCl is able to extract enough genomic DNA from rat whole blood in 30 min. About 725.2-1279.3 ng/mL genomic DNA was successfully extracted from whole blood by using NaCl. This highly efficient, effortless, and green method can be widely used as a lab-on-a-chip component for initial biologic sample preparation.

Abstract: Liquid-suspended rotor micro-mechanical gyroscope uses a high-speed rotating hollow rotor in response to the density of the liquid as the mass to do the angular velocity detection. In order to improve the liquid-suspended gyroscope's performance, this paper suggested a new high performance magnetic driving technology. In this technology, the driving performance is optimized by applying six-phase overlapped driving signal to the twelve driving coils of the stator. With this driving technology, the rotating speed of rotor in 3# industrial white oil can go up to 8700rpm.

Abstract: This paper reports on the magnetic field distribution and magnetic circuit calculating method of micro generator. A micro axial-flux electromagnetic generator is designed as size of Φ6mm×3mm. Traditional magnetic circuit analysis methods are used to retrieve the air-gap magnetic density on no-load micro generator in operation. FEA is done for the micro generator model using magnetic field numerical simulation software. The main parameters of no-load magnetic field and the waveform of induced EMF are obtained. Comparing the results obtained from the magnetic circuit analysis and numerical simulation, the error of air magnetic density is less than 2.54% and the error of the maximum value of induced EMF is less than 2. 68%. The results suggest that magnetic circuit analysis methods can be used for magnetic field analysis of micro axial-flux electromagnetic generators, and be helpful to provide guidance for designs.

Abstract: This paper presents a novel MEMS coplanar microwave waveguide (CPW) structure. The high-resistivity silicon is chosen as the material of substrate and the aluminum is as the metal transmission line because of its high conductivity ,Removing the silicon between the signal line and ground line, underneath the edge of both line,these can effectly reduce the loss.A layer of polyimide is added between the metal and silicon substrates continued to reduce the loss. The simulation results from HFSS show and demonstrate the insert loss is less than the results of traditional CPW.

Abstract: The design, fabrication and characterisation of flexural-mode 3C-SiC resonators are presented. Single-clamped, double-clamped beams and circular membranes, with aluminium and platinum electrodes patterned on top, have been implemented. The structures’ resonant frequency has been investigated optically when the devices are actuated mechanically and electro-thermally. Electro-thermal mixing of two input electrical signals with two different frequencies has been demonstrated. The temperature stability of the 3C-SiC resonators has been characterised.

Abstract: This new hybrid capacitance and micro-leverage amplifier actuator was based on modifying existing structure and mechanism. That overcame the drawback of small displacement of the capacitance actuator in virtual of the micro-leverage amplifier. The amplifier time of the single micro-leverage amplifier was 4.5. Connect the 1×9 array with nine electrostatic capacitance micro-actuators with the amplifier and form a polymer actuator. The actuator whole size was limited to 4×4 mm, the maximum output displacement was 42μm under 15V voltage input. The pull-in voltage of the actuator array was 19V.

Abstract: Current MEMS design methods do not fulfill the needs of emerging complex MEMS devices. In this paper, a systematic direct solid modeling approach for surface micromachined MEMS design is proposed. In this approach, practical model of a surface micromachined MEMS device, designed in a traditional CAD environment, is simplified firstly; after simplification, masks and process sequences are generated through solid-based mask synthesis; then local variation is used to refining the 3D layer model; finally masks and process sequences are verified in rough simulation and accurate simulation. The approach aims at enabling designers to focus on creative design activity in an intuitive mode.

Abstract: In this article, a new technique for controlling crack position and its propagation direction in solder-bonding using Al/Ni exothermic reaction is described. Sputtered Al/Ni multilayer film is able to produce heat instantly by its self-propagating exothermic reaction, and the reactive film can be used as heat source for solder-bonding. During the reaction, however, volume reduction by approximately 12% occurs due to crystal structural change from fcc to bcc and lattice-spacing reduction. Consequently, cracks are produced in the reacted NiAl structure. The cracks negatively affect the strength of the bonded system. We have found a new technique for controlling crack position and its propagation direction. Multiple ignitions for reaction demonstrated that cracks in reacted NiAl film can be controlled. When applying the flash heating technique to wafer-level bonding, cracks are probably produced. If cracks can be fabricated on dicing cut lines by using the simultaneous multiple reactions technique, crack-less solder-bonded Si hermetic packages would be realized.