The actuator system of a hard disk drive (HDD) is very sensitive to vibration circumstances. It is of great importance to study the dynamic characteristics of the actuator system and to control its vibration response. Piezoelectric shunt damping is an emerging vibration suppression technique used to control structural vibration. In this paper, two methods are proposed to improve vibration damping efficiency of the classical piezoelectric shunt damping system and suppress the vibration of the actuator arm. Based on the analysis of the effect of the generalized electromechanical coupling coefficient on the amplitude of the transfer function and damping ratio, the distribution area of the PZT transducer of the shunt damping system is defined as a design variable of topology optimization to maximize the effective area and hence to maximize the converted vibration energy of the actuator arm. Moreover, the vibration control efficiency is improved by introducing a negative impedance converter to eliminate the additional loss resistance of the coil inductor of the shunt circuit. Then the vibration control experiments for the actuator arm of an HDD are carried out to verify the proposed methods. According to the results of FE analysis and modal tests of the actuator system, topology optimization for the PZT transducer is performed on the target modes while the effects of additional stiffness and additional mass of the coupled PZT transducer are also considered. The high damping efficiency of this improved piezoelectric shunt damping system is demonstrated by a 323% maximum increment of damping ratio and 20.36 dB, 8.22 dB and 12.02 dB reduction for its three modes of vibration, respectively.

In this paper, we develop a temperature control system based on DSP chip TMS320F28335 for a small real-time PCR instrument. In the system, PWM waves generated by the DSP passes through power amplifier circuit to drive the peltier, and a pt100 is used as a temperature sensor to build a Wheatstone bridge sensing circuit. The temperature signal from the pt100 is converted into voltage signal. Then the voltage signal goes through the A/D converted module and the Position PID algorithm to adjust the duty cycle of the PWM waves. Experimental results show that the system's rising and cooling rate can reach 4°C/s with an accuracy of 0.2°C.

A method for the vibration and noise reduction of a typical aircraft panel structure under noise excitations is studied. The noise excitations are caused by travelling wave test device, and the experimental is performed by the piezoelectric switching shunt circuit based on the piezoelectric effect.

In this paper we build up a set of simple urinary sediment detection device which is composed of a biological microscope, focusing mechanism, and CCD camera. We apply this device in urinary sediment detection to verify its feasibility. In our experiment, the urinary sediment quality control diluted 200 times is dropped into quantitative analysis plate to detect on the device. We watch and count the number of red and white blood cells in 30 counting pools. Microscopic images are clear and the number of red and white blood cells in these images fluctuates around the average value. Experimental results show that our device is feasible in urinary sediment detection.

In this paper, the typical aircraft panel is excited by the noise induced in traveling wave tube, the vibratory phenomenon of the typical aircraft panel is researched in detail. The piezoelectric vibration of the aircraft panels is damped by Synchronized Switch Damping on Inductor technology (SSDI technology). The acceleration parameters of the structure are controlled and the effect of structural damping is achieved.