Temperature derivatives of P and S wave velocities for mantle high pressure minerals

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The results summarized below.1. Lock-in -Amplifier was introduced for ultrasound spectroscopy. It is indispensable to detect small signals masked by back ground noise. It also useful to reconstruct signal pattern disturbed by noise. The "cos" component and "sin" components of the signal simultaneously measured by the Lock-in-Amplifier so that we can conduct background correction separately for the two components.2. We confirmed that handmade -transducers are useful up to 50 MHz. This innovation, combined with the above improvement, is important for future development of high frequency ultrasound spectroscopy.3. Resonance frequency shift by clamp force was also examined fro rectangle specimen. The proposed mechanism for the frequency shift was confirmed again in rectangle resonance method as well as sphere resonance method. The knowledge can be applied for identification of resonant peaks in the future study.4. Measurements of β, γ spinels and perovskite have finished. The implications of the results are now considering.