著者

岩田 武徳 間瀬 淳 北條 仁士

出版者

九州大学大学院総合理工学府

雑誌

九州大学大学院総合理工学報告 (ISSN:13467883)

巻号頁・発行日

vol.28, no.3, pp.329-334, 2006-12

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Alien substance mixture accident inside foods is serious problems for both consumer and company side. The systems that can measure the different kinds of alien substance have been required. The detecting systems using X-ray, SQUID sensor, and supersonic wave as well as metal detector have been developed and been in the market, however, they are, in many cases, appropriate for the detection of metal alien substance. We have been studying the system using millimeter-waves with frequency of 50-140 GHz to detect both metal and dielectric alien substance. The scattered and transmitted waves are detected using a heterodyne receiver. The angular distribution of the scattered wave is analyzed to obtain the dispersion, auto-correlation function, and the Fourier spectrum. The neural network analysis is utilized to judge the mixture and the size of alien substances. It is shown that the alien substance having 1-3 mm size can be detected in spite of the materials by the present system. By using short wavelength millimeter wave, it is expected to detect even less than 1 mm alien substance.

著者

竹村 素直 間瀬 淳 近木 祐一郎 北條 仁士

出版者

九州大学大学院総合理工学府

雑誌

九州大学大学院総合理工学報告 (ISSN:13467883)

巻号頁・発行日

vol.28, no.4, pp.367-370, 2007-03

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Recently there are much interests in using microwave radar for monitoring and diagnostics of living subjects. In contrast to infrared and visible lights, microwave can propagate through dielectric materials, such as, concrete wall, ground, and human body. An ultra-wideband (UWB) radar is the promising method of such detection, since it gives good spatial resolution as well as good penetration characteristics for various materials. In this report, we describe the development and application of an ultrashort-pulse radar (USPR) having ultra-wideband characteristics, which frequencies are in the range of 7-15 GHz. The simulation of breast cancer detection using the USPR is performed.

著者

平野 賢治 豊田 裕司 木邊 厚視 山本 直嗣 中島 秀紀

出版者

九州大学大学院総合理工学府

雑誌

九州大学大学院総合理工学報告 (ISSN:13467883)

巻号頁・発行日

vol.35, no.1, pp.1-5, 2013-09

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The abundance ratio of the doubly charged ions in an ion thruster plume was measured in order to estimate the thrust and validate a numerical simulation code for lifetime validation of ion thruster. An E×B probe was used for the estimation of the ratio of doubly charged ions to singly charged ions. The ratio of doubly charged ions to singly charged ions is 0.04 at an incident microwave power of 8 W and a mass flow rate of 20 μg/s. The ratio is decreased with increase in mass flow rate. This is because the increase in mass flow rate leads to the decrease in mean free path, and electrons get less energy from the microwaves. The E×B probe can estimate the ion velocity and the average velocity of the accelerated ions is estimated as 3.7×10^4 m/s at a screen voltage of 1000 V, which is reasonable compared to the theoretical value.

著者

林 真照 渡辺 幸信 加来 大輔 中島 秀紀 相良 建至

出版者

九州大学大学院総合理工学府

雑誌

九州大学大学院総合理工学報告 (ISSN:13467883)

巻号頁・発行日

vol.27, no.3, pp.321-328, 2005-12

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We have investigated the response of a 6Li loaded neutron coincidence spectrometer to MeV neutrons. The spectrometer has a structure consisting of three 6Li-glass scintillators in a liquid organic scintillator BC-501A, which can detect selectively neutrons that deposit the full energy in the BC-501A using a coincidence signal generated from the capture event of thermalized neutrons in the 6Li-glass scintillators. The efficiency and response functions were measured using 4.7, 7.2 and 9.0 MeV mono-energetic neutrons, and were compared with those derived by combination with both neutron transport calculation in the spectrometer and scintillator response calculation. The calculation results showed fairly good agreement with the measured ones. Finally, the response function matrices were obtained for 1 to 10 MeV neutrons.