In this paper, we developed a contactless monitoring technique of liquid for measuring the concentration of liquid. This sensor is composed of dual sensing capacitors and quartz oscillation circuits. We succeeded in measuring dielectric and conductivity change at the same time by using dual frequency. Therefore, it can measure liquid tailored to its physicochemical properties with wide frequency range. In this study, we succeeded in monitoring change of concentration of cutting oil. The proposed sensor can be expected to be used for liquid monitoring.

In the transurethral lithotripsy using flexible endoscope (f-TUL), a flexible ureteroscope is inserted into the bladder from the urethra and breaks calculus by laser transmitted through an optical fiber. Because laser irradiation position is fixed in the endoscopic field of view, it is difficult to perform precise alignment of laser to the target when the target has relatively complex structure. To solve the problem, a thin multidirectional active bending mechanism of the laser fiber using Shape Memory Alloy (SMA) wire has been developed. This device has 170 µm diameter channel for laser fiber and is controlled by 3 SMA wires. Maximum outer diameter is 1.1 mm and length of the bending part is 10 mm. The fabricated bending mechanism with laser fiber bends up to 10 degrees. Surface temperature was measured by using a thermocouple in water bath and was lower than 41°C.

The purpose of this study was to explicate the mechanism of transition storage modulus and loss modulus under external magnetic field. Magneto-rheological elastomer (MRE) is expected to be used as damping material and actuator controlled by an external magnetic field. However, magnetic particles' behavior inside of MRE has not been explained completely. Especially, the mechanisms of loss modulus transition under external magnetic field has not been known well. We constructed a simple model with two magnetic particles, and try to make MRE behavior clear. In this report, we show a data of the viscoelastic property of MRE which consists of magnetic particles and polydimethylsiloxane (PDMS). The obtained viscoelastic property is explained by using two magnetic particles model.

We measured flow speed of a moving object in a water with Doppler effect using a MEMS ultrasonic receiver. This measurement is aimed for non-invasive blood pressure measurement. We proposed a wide frequency range receiver to measure both blood flow speed and vessel diameter at the same time in a blood vessel. Our sensor has a piezoresistive cantilever which is put on the boundary between air and liquid in a device. According to this structure, proposed receiver can measure acoustic waves from Hz to MHz order frequency, so that we can obtain blood flow speed (MHz order), and blood pressure change (Hz order) with the same device. On this paper, we measured flow speed ranging from 64.0 to 76.3 mm/s with 5.6 to 19% error.

This research reports capacitance-voltage (CV) changes of capacitive micromachined ultrasonic transducers (CMUT) for ultrasonic diagnoses. The CMUT constitutes an electrostatically vibrating film, which is fabricated by deposition processes of SiO₂ and SiN films as insulator and TiN and Al films as top electrode on an Si substrate. The ultrasonic waves are transmitted by addition of AC voltage between the top electrode and the Si substrate, whereas the reflective ultrasonic wave are received with the vibrating film and converted to the electrical signals for ultrasonic diagnostic images. There is a problem that the CV changes of CMUT occur due to charge-injection into the insulator, since a high AC and DC voltages are applied for driving the vibrating film. Thus, it is necessary to suppress the change in CV characteristics of the CMUT due to charge-injection. It is clarified that the CV drift due to charge-injection can be decreased by forming the top electrode so as to cover the vibrating film. Also, the CV drift is able to be suppressed by setting the driving voltage to be equal to or less than the collapse voltage.

In this report, we constructed a simple mathematical analysis model for a new MEMS deformable mirror using an electrostatic piston array. The deformable mirror has been developed as a wave-front compensation device in adaptive optics for retinal observation. The device realizes a large convex deformation with a low operation voltage because of moving bottom electrodes on the pistons. The constructed model is based on the plate theory and simple superposition of the actuation components. The calculated deformation analyzed using this model agrees well with that analyzed using the finite element method not only in deformation shape but the peak-valley deformations. In addition, the calculation time is much shorter, so the model can be used for design optimization of the device.