IEEJ Transactions on Fundamentals and Materials
Online ISSN : 1347-5533
Print ISSN : 0385-4205
ISSN-L : 0385-4205
Volume 142, Issue 10
Displaying 1-7 of 7 articles from this issue
  • Yui Okuyama, Yuka Yasuzawa, Hirotake Sugawara
    2022 Volume 142 Issue 10 Pages 397-405
    Published: October 01, 2022
    Released on J-STAGE: October 01, 2022

    In this study, we have measured the negative ion mobility in O2 at high pressures with a little amount of H2O concentration between 15 and 17000 ppb. After that, we carried out a Monte Carlo simulation using mobility of electrons, that of the ions obtained in the measurements, and rate coefficients of ion-molecule reactions. As the results, the mobility value 2.39 cm2/V·s of O4ˉ is obtained in ultrahigh purity O2 of which the H2O concentration is between 15 to 100 ppb. Moreover, the mobility decreases with the H2O concentrations at which the ion species are considered to be O2ˉ·(H2O)n (n = 1, 2, 3). Then, we compared the experimental result with that of the simulation and estimated the ion mobility and rate coefficients of ion molecule reactions. Simulation results using estimated values of the ion mobility and rate coefficients agree well with measurement results.

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  • —Assessing the Effect of the Pulse Width of Transient Electromagnetic Field—
    Yuki Haji, Yoshihisa Otsuki, Masao Masugi
    2022 Volume 142 Issue 10 Pages 406-412
    Published: October 01, 2022
    Released on J-STAGE: October 01, 2022

    This paper presents an effect of transient-electromagnetic fields (or pulsed electromagnetic fields) on the growth of the radish. In our experiment, two kinds of transient electromagnetic fields by spark discharges were applied to seeds and seedlings of the radish. When generating spark discharges, the pulse widths of discharge current (800 A) were set to 3 µs and 15 µs, respectively. Based on measured discharge currents, we also evaluated the energy level of electromagnetic fields by using an electric dipole model. The analytical results quantitively confirmed that a waveform with a short pulse-width (3 µs) can generate high frequency energy component although the total energy of a waveform with a wide pulse-width (15 µs) is greater. Then, regarding the growth rate of the radish, we found that the weight of enlarge roots (or tuberous root) for the pulse width of 3 µs became greater than the others (control [no application] and the pulse width of 15 µs) by around 23-38%. In addition, the t-test-based statistical assessment confirmed that there were statistically significant differences in the mean value between the control and 3 µs groups at the significance level of 5%.

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Technical Note
  • Mikio Mori, Takuya Maezawa
    2022 Volume 142 Issue 10 Pages 413-418
    Published: October 01, 2022
    Released on J-STAGE: October 01, 2022

    Musical whistling competitions have been regularly held in Japan since 2005. The author serves as a judge at some of these competitions. However, defining what constitutes whistling may be problematic and may pose a challenge at the time of judging. Pucker whistling, which is achieved by puckering the lips, is the most common type of whistling. However, other styles may be used in competitions. Recently, K. Harvest introduced 45 different types of whistling methods in a video, which are classified in this study according to the sound source, the fundamental frequency determined by the vocal tract resonance, and the lip-opening characteristics. In addition, we subdivided these 45 types of whistling into 99 categories based on the distinction between blowing sound and sound absorption and the presence or absence of overtone in the generation process. Similar to the speech generation process, the whistle generation process can be regarded as a combination of three actions, that is, sound source generation, vocal tract tuning, and radiation from the lips.

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