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Biological micro-dissection has a wide range of applications in the field of molecular pathology. The current laser-assisted dissection technology is expensive, and laser radiation can lead to sample contamination. As an economical and pollution-free micro-dissection method, piezoelectric ultrasonic micro-dissection has a wide application prospect. However, the performance of the current piezoelectric ultrasonic micro-dissection technology is unsatisfactory. In this paper, a novel piezoelectric ultrasonic micro-dissection device based on a flexure mechanism is proposed in order to solve the problems of low dissecting precision and excessive wear of the dissecting needle caused by the harmful lateral vibration of the current piezoelectric ultrasonic micro-dissection device. By analyzing the flexibility of flexure hinge, the type of flexure beam and the optimal design parameters are determined. Through comparing the harmonic response simulation analysis of the micro-dissection device based on a flexure mechanism and the traditional micro-dissection device without the flexure mechanism, the newly designed micro-dissection device achieves the best vibration effect when the driving frequency is 28kHz, compared with the traditional micro-dissection device, the lateral vibration suppression effect is improved by 68%. Then, based on the 3D printing technology, a prototype of a novel micro-dissection device was produced, and its performance was tested. It was found that the flexure mechanism did indeed suppress the lateral vibration of the needle tip. Finally, the experiments of 5μm thick paraffin-embedded rat liver sections were carried out, and the effects of different dissecting parameters on the dissecting effect were analyzed, and the optimal dissecting parameters were obtained. By comparing the dissecting effects of the tissue sample and the wear condition of the needle tip between the novel micro-dissection device and the traditional micro-dissection device under their optimal dissecting parameters, it is proved that the suppression of harmful lateral vibration not only significantly improves the dissecting effect, but also improves the service life and durability of the dissecting needle, which is beneficial to reduce the equipment costs.

Antenna array has been widely used due to its advantages of high gain, low side lobe and narrow beam. For vehicle radar, antenna array is required to have narrow beam, wide measurement range, middle and long distance coverage in order for the high accuracy, wide angle range, middle and long distance of detection. Therefore, according to the Taylor polynomial microstrip antenna array theory, a 16-unit series-fed microstrip antenna array was designed in this study. Based on this and the beam forming technology, the 3-beam transmission antenna was designed to realize the division of airspace. Then the high frequency structure simulator and the optimization design module of the advanced design system are adopted for the frequency sweeping analysis, and the design size model data of antenna is optimized. The final experimental result shows that the design is qualified for the requirement of spatial division of narrow antenna beam.

In order to achieve higher gains and lower side lobe in antenna design, array antenna is conventionally adopted. Besides, Chebyshev polynomial amplitude ratio is widely employed in the design, and it optimizes the main and side lobes under specific main lobe width and side lobe level. However, the actual product can be easily affected by machining error and the antenna material property, which change along with the frequency. The influence is evident at millimeter waves level owing to the short wave length. In micro-strip antenna applications, the test frequency for key parameters of high-frequency base material is limited by 10 GHz, while the parameters have no explicit definition at higher frequency. Therefore, a large mismatch between the design and actual product may exist when the frequency reaches 77 GHz or higher. In this paper, a weighting method is proposed to compensate parameters of the base material and machining error. Based on this method, simulation result of the design is revised to match tested result of actual product.

In order to improve the positioning accuracy of magnetic levitation positioning platform and realize high-speed and high-precision positioning, this paper adopts the planar four-wheel drive structure based on the idea of modularity. Based on this structure, the relationship between the command coordinates and the driving coordinates is deduced, and the movement and rotation dynamics model of the positioning platform is established. For the multi-input and multi-output coupling system of magnetic levitation positioning platform, the sliding mode control strategy based on exponential reaching law is proposed, and through simulation verification, compared to the traditional control method, magnetic levitation positioning platform can acquire fastness and stability. Finally, a three-degree-of-freedom magnetic levitation positioning platform is built. To achieve the positioning platform of the closed-loop feedback, the displacement of the positioning platform is detected in real time by the laser displacement sensors. From the experimental results, the platform's stroke is 50mm×50mm, after about 153ms, the platform stabilizes to 50mm in the X direction and after about 198ms, the platform stabilizes to 50mm in the Y direction, the repeated positioning accuracy in XY plane can be obtained within 5μm.