IEEJ Transactions on Sensors and Micromachines
Online ISSN : 1347-5525
Print ISSN : 1341-8939
ISSN-L : 1341-8939
Volume 116, Issue 10
Displaying 1-6 of 6 articles from this issue
  • Kiyoshi Toko
    1996Volume 116Issue 10 Pages 409-412
    Published: November 20, 1996
    Released on J-STAGE: April 01, 2009
    JOURNAL FREE ACCESS
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  • Shoji Kawahito, Masayuki Sutoh, Akira Yamasawa, Yoshiaki Tadokoro
    1996Volume 116Issue 10 Pages 413-421
    Published: November 20, 1996
    Released on J-STAGE: April 01, 2009
    JOURNAL FREE ACCESS
    This paper presents highly-sensitive fluxgate magnetic sensors based on silicon microtechnology and electrodeposited magnetic thin films. To achieve high sensitivity, we propose a coil structure that both the excitation and the pickup coils are wrapped around a thin-film core. The optimal coupling structure between excitation and pickup coils is investigated. The closely-coupled coil structure that a one turn of excitation coil and a few turns of pick-up coil are wound alternatively around the magnetic core is effective to achieve high sensitivity. In general, the magnetic performance of the core prepared by electrodeposition is degraded due to the thermal treatment process during the fabrication. The addition of indium in the plating bath of permalloy greatly reduces the degradation of magnetic core due to the thermal treatment process. An improved basic micro fluxgate sensing element chip employing new-type coil structures and the indium-added permalloy prepared by electrodeposition is fabricated. The maximum sensitivity of the fabricated sensor is measured to be 2700V/T at the excitation frequency of 3MHz. The noise spectral density is measured to be 0.6nT/√Hz at 10Hz.
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  • Defrosting Detection of Frozen Foods
    Tetsuo KUBOTA, Hideki NAKANO, Kohji KOSHIJI, Eimei SHU, Michiko SUZUKI ...
    1996Volume 116Issue 10 Pages 422-428
    Published: November 20, 1996
    Released on J-STAGE: April 01, 2009
    JOURNAL FREE ACCESS
    Foods have different dielectric properties which depend on the frozen and defrosted condition. As a frozen food is heated by a microwave oven for defrosting, its dielectric property varies with temperature. Consequently, the microwave reflection coefficient in the feed waveguide connected to the oven cavity also varies with temperature. We suggest to detect the reflection coefficient using a loop coupling directional coupler. The coupling characteristics of the loop coupling directional coupler was analyzed, and the directional coupler was designed according to the results obtained from the analysis and formed on a glass base-epoxy resin laminate. Measuring the frequency characteristics of the coupler, we obtained the coupling coefficient of 43.6dB and the directivity of 20.6dB at 2450MHz. The coupling coefficient and the directivity were sufficient for the measurement of the reflection coefficient from microwave oven. We named this loop coupling directional coupler "High Power Sensor". We inserted mushed potato used as a sample food into a waveguide excited by microwave power of 300W for heating. Using the High Power Sensor attached to a wall on the waveguide, we measured the reflection coefficient from the mushed potato heated from -20°C to 10°C. As a result, it was found that the minimum reflection coefficient existed in the range of temperature from -5°C to 0°C well known as the optimum defrosting condition for cooking. Further, we have developed a microwave oven with defrosting function using the High Power Sensor and tried to detect the optimum defrosting condition for various frozen foods. As a result, we confirmed that the optimum defrosting conditions of the various foods for cooking can be detected by the High Power Sensor.
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  • Hiroshi Ishida, Takamichi Nakamoto, Toyosaka Moriizumi
    1996Volume 116Issue 10 Pages 429-434
    Published: November 20, 1996
    Released on J-STAGE: April 01, 2009
    JOURNAL FREE ACCESS
    A new method for localizing an odor source by mimicking the behavior of silkworm moths is proposed. A male silkworm moth is able to track airborne sexual pheromone to its female counterpart. During the search, a moth draws air from its front to its two antennae by wing vibrations, and turns toward the antenna more strongly stimulated by the pheromone. An artificial system with this mechanism has been realized using a small fan and plural gas sensors instead of the moth's wings and antennae, respectively. The system is called an 'odor compass' since it continuously points to an odor source by rotating the probe to the sensor with the largest response. The capability of its directional probing is successfully demonstrated by the results of estimation of the odor-source direction in a clean room. Furthermore, the improvement of the system to realize the three-dimensional localization, which is often required in a practical environment, is reported, and its feasibility is demonstrated.
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  • Takaki Kanno, Kaneo Mohri, Ken-ichi Bushida
    1996Volume 116Issue 10 Pages 435-440
    Published: November 20, 1996
    Released on J-STAGE: April 01, 2009
    JOURNAL FREE ACCESS
    A new sensitive and low power consumption micro magnetic sensor is presented using an amorphous wire MI head installed in a C-MOS multivibrator. The impedance in the MI head is sensitively changed with more than 80%/Oe due to a sharp current magnetization during a transient period in the C-MOS inverter. The sensor circuit operates with a high stability due to a current source like operation in the source line and the independence of the field detection sensitively on the oscillation frequency of the multivibrator. A power consumption is less than 1mW in the C-MOS multivibrator having a 250kHz oscillation frequency.
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  • Toshiyuki Tsuchiya, Osamu Tabata, Jiro Sakata, Yasunori Taga
    1996Volume 116Issue 10 Pages 441-446
    Published: November 20, 1996
    Released on J-STAGE: April 01, 2009
    JOURNAL FREE ACCESS
    In this paper, a new tensile tester for thin films is presented. This tensile tester has a grip that fixes a thin film specimen using electrostatic force. The tester was constructed in a scanning electron microscope (SEM) chamber. Using this tester, the tensile strengths of polycrystalline silicon (poly-Si) thin films have been measured. The tested part of the specimen is 30-300μm long, 5μm wide and 2μm thick. The fracture of the poly-Si thin film was brittle. The mean tensile strength was 2.0-2.6GPa, depending on the length of the tested part. The size of the critical flaw that initiates fracture of the poly-Si thin film is 28-47nm, rather small than the grain size of the poly-Si thin film.
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