Eddy current measurement technology are widely used in instruments such as displacement meters, vibration meters, and non-destructive testing equipment. In this paper, we proposes eddy current speed meter using a rectangular coil and clarifies its speed characteristics using an analytical method. A rectangle has a shape effect not present in a circle and an improvement in characteristics due to the coil system aspect ratio and also improvement in the flux utilization and miniaturization of the sensor can be expected. Therefore, after verifying the validity of the analytical solution through experiments, the speed characteristics are calculated for a case in which the parameters relating to the moving conductor-slab are varied and that in which the coil system aspect ratio is varied. In addition, essential documentation for the optimum design of rectangular coil eddy current speed meter is obtained.

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We proposed a proximity and tactile sensor using capacitance measurement. The proposed sensor consists of the three electrodes (X₁, X₂, Y). The capacitance between X electrode (X₁ or X₂) and Y electrode is measured by switching between X₁ and X₂. In addition, the other electrode (X₂ or X₁) is grounded. The capacitance between X₁ and Y electrode is detected the object before contact (proximity range), and discriminate the material on contact. In addition, the capacitance between X₂ and Y electrode is detected the indentation on contact. In the experiment, detection of the object before and after contact, and identification of two kinds of materials on contact were demonstrated. This technique may be applicable to proximity and tactile sensor for robot and touch screen.

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The femtosecond laser (fs laser) is generally used in order to transmit and receive the terahertz (THz) wave. But the fs laser is very expensive. The cost of equipment is an important factor to adopt inspection equipment. Therefore, we developed the terahertz time domain spectroscopy (THz-TDS) using laser diode (LD) which cheap laser. The measured samples are concretes and cables. Concretes and cables are generally inspected by X-rays or ultrasonic waves, and those inspections are required to inspect the measuring object by non-destructive and non-contact. We measured about the sample from which the diameter of glass spheres differed, and the sample which mixed glass spheres with cement. We disassembled the cable and measured the material separately.
In THz-TDS using fs laser and LD, we confirmed correlation between transmission and the diameter of glass spheres, and correlation between transmission and the mixture ratio of cement and glass spheres. Moreover, we confirmed that we recognized the form of the conductor in the cable by transmission of the THz wave through the material of the cable. We compared the measurement result of having used fs laser with the measurement result of having used LD, and we validated that the equipment using LD is suitable for the inspection equipment.

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Terahertz waves are effective for detection of delamination of dielectric coatings applied onto a metal surface. In most cases, the thickness of the air gap which results from delamination is much smaller than the spatial width of the terahertz pulse, so the reflections from the upper and lower boundaries of the air gap, and the multiple reflections within the air gap are not temporally resolved. The reflection of the terahertz pulse was calculated based on an impulse response model, which included the effects of multiple reflection. The calculation results were compared with the experimental results in the case of reflection from a three-layer structure consisting of a polyethylene plate, air gap, and metal plate. The results showed that an air gap with a thickness of about 30 µm can detected, even when the lower limit of the time-resolved measurement was 120 µm.

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The present study analyzed the effects of repetitive transcranial magnetic stimulation (rTMS) on brain activity. P300 latency of event-related potential (ERP) was used to evaluate the effect of low-frequency and short-term rTMS. We investigated the effect of P300 latency by 1.0 or 0.5 rTMS over the supramarginal gyrus (SMGs) and dorsolateral prefrontal cortex (DLPFCs). The P300 of ERP was elicited by auditory odd-ball task, which was delivered before and shortly after rTMS. ERP was measured prior to rTMS as a control, and after the rTMS. The rTMS was performed for 100 pulses. We found that the individual frequency difference of rTMS affected P300 latencies. Compared to the control, with 1.0 Hz-rTMS to the left-SMG, P300 latencies decreased. Latencies were shorted by approximately 18 ms at Fz electrode. With 0.5 Hz-rTMS to the left-SMG and 1.0 Hz-rTMS to the left-DLPFC, P300 latencies increased. Latencies were lengthened by approximately 26 ms at Fz electrode with 0.5 Hz-rTMS to the left-SMG, and by approximately 18 ms at Fz electrode with 1 Hz-rTMS to the left-DLPFC. In contrast, P300 latency was little altered by rTMS over the right-SMG and right-DLPFC. The results suggested that the effect of low-frequency rTMS had difference by stimulus frequency and stimulation point.

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