Eight types of polyurethane were synthesized using seven types of diisocyanate. It was found that the elasto-optical constant depends on the concentration of diisocyanate groups in a unit volume of a polymer and the magnitude of anisotropy of the dielectric constant of diisocyanate groups. It was also found that incident light scattered when bending stress was generated inside photoelastic polyurethanes. A high sensitive tactile sensor for robot hands was devised using one of the developed polyurethanes with high photoelasticity.

We report a novel elasticity control technique for piezoelectric lead zirconate titanate (PZT) ceramics using an electric circuit that behaves as a “negative capacitor” (hereafter referred to as a negative-capacitance circuit) for application to sound shielding technology. A feature of this technology using an optimized negative-capacitance circuit is effective sound attenuation regardless of the PZT ceramic type or frequency ranges of the noise. In this experiment, we prepared three types of PZT ceramic with different dielectric and piezoelectric characteristics. We improved the circuit constants of negative-capacitance circuits for the three kinds of PZT ceramic with different physical properties. We measured the transmission loss attenuation factor of the three types of PZT ceramic in the frequency range from 1 to 100 kHz. We found that the transmission loss attenuation factors of all three types of ceramic were greater than 20 dB in the frequency range from 1 to 100 kHz.

A wireless triggering system for acoustic anemometers using an acoustic probe with a long baseline is investigated. Acoustic probes for measuring micrometeorologic parameters, such as temperature and wind velocity, are used as noncontact and nondestructive methods. The acoustic probe with a long baseline was previously proposed by the authors and investigated to form a sensing grid system for micrometeorologic measurement. The authors have also partially investigated a wireless sensing grid using a wireless local-area network (LAN). However, because of the synchronization problem between sensor nodes, the trigger line has been left wired. In this paper, the problem of synchronization is solved by investigating a wireless triggering system using frequency modulated (FM) radio waves. The primitive triggering system of FM radio waves has some instability on time synchronization depending on such the communication environment as signal-to-noise ratio (SNR). To overcome the influence of the instability, a cross-correlation method is adopted to the triggering system. As a result, the time synchronization errors of the trigger system were reduced by up to one tenth. In addition, not only the instability problem but also other larger errors are compensated by the proposed system in an experimental wind velocity measurement.

We evaluate the vibration in the edge face of a poly(L-lactic acid) (PLLA) film from the propagated signal of an ultrasonic wave generated by the excitation force of the edge. Although the excitation area is too small to drive the edge face, the vibration can be measured only using the fixing method that does not suppress the resonance and the equipment with a high signal-to-noise ratio. This is considered to be due to the fact that the theoretically calculated force of the PLLA film is more than 10 times larger than that of a well-known ferroelectric polymer film, poly(vinylidene fluoride). We confirm that the film functions as a resonator and can be applied to a resonated transducer. In spite of the vibration in the edge face of the polymer film, we observe compliant responses to excitations by burst or rectangular waves. The practicality of a resonator can be suggested.

We apply a general random walk model to the study of the ATPase's one-dimensional translocation along obstacle biological environment, and show the e ects of random obstacles on the ATPase translocation along singlestranded DNA. We nd that the obstacle environment can reduce the lifetime of ATPase lattice-bound state which results in the inhibition of ATPase activity. We also carry out the ranges of rate constant of ATPase unidirectional translocation and bidirectional translocation. Our results are consistent with the experiments and relevant theoretical consideration, and can beused to explain some physiological phenomena.PACS numb e r s :