Papers by Author: Zhuo Qing Yang

Abstract: Graphic nanoporous copper (NPC) was prepared by a new method. Cu68Zn32 and Cu36Zn64 (atomic percentages) precursor alloy thin film was deposited by electro-deposition in acidic alloy plating solution and then dealloyed in hydrochloric acid to fabricate nanoporous copper (NPC) with pore size from 30nm to 100nm. The results show that the microstructure of NPC can be controlled by changing alloy plating solution and dealloying process, this process also maintains compatibility with micro-fabrication technique.

Abstract: This paper describes the designing and producing of a multi-direction tiny force switch, which is based on the technology of micro-surface processing on privative silicon. The switch is mainly formed by shore, overhanging spring, movable electrode and fixed electrode. Its’ structure material is Ni. The parameters of switch are confirmed by doing finite-element analysis with ANSYS. And rigidities of structure both on horizontal direction and vertical direction are analyzed by using ANSYS to ensure that the uniformity of switch rigidity is qualified. After producing the switch, the rigidity of switch is tested by using bonding tester. The test result shows that the rigidity is almost qualified with requirements.

Abstract: A fully integrated micro electromagnetic vibration energy harvester based on MEMS technology is designed and its mechanical and electromagnetic characteristics are analyzed by using Finite Element method (FEM). Structure static, modal and harmonic analysis of spring-magnet system was carried out by ANSYS software. Ansoft Maxwell software was used to simulate the electromagnetic characteristics of the energy conversion system, especially the relationship between the output performances of the structure and parameters of the coil. The optimized model is designed and the optimization principles could provide a reference for the future electromagnetic vibration based harvester design.

Abstract: Microscale polyurethane modified epoxy resin film has been fabricated using MEMS tehnologies in the present paper. The effect of different process conditions on the thickness of fabricated film was discussed. The microscale film shows smooth and uniform surface morphology. The tensile test of the film by DMA indicates its tensile strength and Young's modulus are approximately 55MPa and 1.8GPa, respectively. The fracture section of the film was characterized by SEM. In addition, the interface bonding strength of the fabricated film between Ni substrate is much higher than Parylene-C and SU-8. This microscale polymer film is promising in several smart MEMS fields, especially bio-MEMS structures.

Abstract: A planar micro triggered spark gap switch with three electrodes was designed and fabricated based on non-silicon surface micromachining technology. It consists of two main electrodes, the shape of which is semicircle, and a triggering electrode which is a thin strip. The gap distance between two main electrodes is 800μm. Benefitting from MEMS technology, the switch is integratable and its cost has the potential to be reduced. The designed switch has been optimized and tested. It gives out a pulse current with peak of 5165.21A and 129.6ns rise time. The test data has an agreement with the simulation results.

Abstract: A micromachining technique has been developed for the fabrication of microscale polymer-bonded magnet. Two types of lithographically defined molds, photoresist mold and electroplated metal mold, were introduced. Photoresist mold is convenient, while electroplated metal mold can be fabricated on the glass or steel substrate which can bear much more compression. NdFeB films of thickness between 50 and 500 µm were prepared by micro-patterning of composites containing 83-95wt% of commercial NdFeB powder after curing at the room temperature. Magnetic properties mainly depend on the types and percentage of volume loading of magnetic powder. Coercivity of 772.4kA/m (9.70kOe), remanence of 275.1mT (2.751kG), and energy product of 22.6kJ/m³ (2.8MGOe) have been achieved. This easily developed magnet could be a promising candidate for applications in magnetic microelectromechanical systems (MEMS).