Research on construction of ultrasonic system not limited by the diffraction effect

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1) Construction of Displacement Measurement System: In 2007, the system was improved to measure the dynamic dislocation. To achieve the phase switching, external high speed electronic method was newly introduced. As the result of this improvement, high speed operation can be accomplished. The numbers of reference signals were also increased four to eight. Mechanical parts were also improved to make a high precision measurement. Additionally, effects of acoustical external perturbations, especially temperature fluctuation, were measured. The system was totally improved with all things described above.2) Design of the pinhole based Acoustic System (PAS): PAS system including a pinhole which has much smaller diameter tan the wave length was constructed. This pinhole method originally developed by the author realized a high resolution measurement. The acoustic properties such as acoustic field and both lateral and length resolutions were measured. The relationship between resolution and diameter were also measured. This new system was applied in the imaging for the surface topological imaging.3) Constriction of final system: Since both the dislocation system and PAS have a common part in the mechanical and electrical system, so that the combined system was constructed. The performance of the system were measured and considered in detail. The unique experimental demonstrations were accomplished to clarify the usefulness of the system.