張 月琳

This paper proposes a health monitoring system for detecting a blockage in a pipe using the acoustic vibration excitation with high power laser. Non-contact acoustic impulse excitation can be applied to acoustic fields by using a shock wave generated by laser-induced breakdown in air. A high-power Nd:YAG pulse laser is used in the present vibration testing system for generating the laser-induced breakdown in acoustic fields. The laser excitation makes a precise measurement of the acoustic resonant frequency in wide frequency range possible with high reproducibility. The acoustic resonant frequency changes by the blockage and its position in the pipe. In this study, the detection of the blockage in the pipe is focused. The acoustic resonant frequencies in the pipe with/without the blockage are measured by a microphone. Then the position of the blockage is identified by evaluating the cross section ratio between the pipe and the blockage analyzed from the measured data.

This study proposes a tuning method of model-based controller with adaptive parameters in the controller, that is effective to maintain the control performance and stability for characteristic variation of the structures. The main idea of this tuning method is tuning the poles of the controller that have great effect on the control performance and stability. Simultaneous perturbation stochastic approximation (SPSA) is used as tuning algorithm. The vibration control simulation by using the proposed tuning method is carried out. The perturbations are given to the model of the controlled object to change its physical characteristics, and the controller is tuned for adapting to these changes. This study shows the effectiveness of the proposed tuning method by conducting the simulations.

In this study, the resistance of PC 12 cells against strain is investigated by the impact test. The resistance of cell body is evaluated by the cell mortality and the citotoxicity. The axonal injury is evaluated by the morphological observation. The cell mortality and the citotoxicity increase according to the increase of strain rate. PC 12 cells with axons show larger cell mortality and citotoxicity than without axons, and the axons of injured/dead cells show the morphological features of axonal injury. This result shows the difference between the impact resistance of neuronal cells with axons and without axons quantitatively.

The finite element analyses of the cerebral contusion based on judicial autopsy reports were performed in order to show the relationship between the input force duration and occurrence of the coup contusion, contrecoup contusion. In finite element analysis the skull fracture was taken into consideration. The result showed that coup contusion would occur when impacted by light weight impactor with high velocity which yielded short force duration, and contrecoup contusion would occur when impacted by heavy weight impactor with low velocity which yielded long force duration. When force duration was less than 5ms, coup contusion tended to occur, and contrecoup contusion tended to occur when force duration was more than 5ms.