In this report, we simulate the influence that global warming gave to the underwater sound propagation using the watre temperature of K-1 model result from 2001 to 2100. As a result, it was clarified that changing the profile was few in deep water though the sound speed profile on the surface was greatly changed in the sound propagation from Alaska to Hawaii. Moreover, it was clarified that the sound from Alaska is propagated to the Hawaii though the SOFAR axis is changed on the way by the simulation of the sound source frequency 55 Hz. However, the surface is thought that the global warming influence is large. A more detailed examination is necessary for the possibility of the influence on the communication of the marine mammals.

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The double-mode miniature cantilever-type ultrasonic motor was fabricated using the array-type multilayer piezoelectric ceramics (array-type MLPC) of (Sr, Ca)_2NaNb_5O_<15> (SCNN) such as Pb-free piezoelectric materials, and the electrical driving properties were investigated. The array-type MLPC was arranged in a 2x2 matrix on the actuators. The ultrasonic motor of SCNN array-type MLPC started to rotate at 1.7V_<p-p,>, and showed such characteristics as revolution speed of Ω_0=1000 rpm, a torque of T_0=2.6μNm at 9V_<p-p>. On the other hand, the motor using Pb (Zr, Ti)O_3-Pnb(Zn, Nb)O_3(PZT) showed Ω_0=1000 rpm, a torque of T_0=2.6μNm at 1V_<p-p>. SCNN motor was not so different from PZT motor, however the SCNN motor needed 10 times as high voltage as the PZT motor. By using the array-type MLPC, the driving voltage was reduced by a half, and the driving properties were improved.

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