過去の学会誌一覧

Vol.31 No.2 通巻114号 (2004年/平成16年)

研究 水中聴覚における外耳道の空気泡の影響について
Effects of Air Bubble in the Ear Canal for Underwater Hearing
*1 Kazuoki KURAMOTO, Kensei OIMATSU, Shin'ya KUWAHARA (Japan Coast Guard Academy)
*2 Shizuma YAMAGUCHI (Faculty of Engineering, Yamaguchi University)
Abstract:
In order to examine the effects of air bubble in the ear canal for underwater hearing, detailed measurement of minimum audible field (MAF) in audio frequency (50 Hz~8 kHz) and comparison of loudness were carried out at two conditions as below, 1) the air bubble remains in the ear canal and 2) the ear canal is filled with water. As the result, in the high frequency region over about 300 Hz, it is highly sensitive to hearing in the case that the air bubble remained in the ear canal. In the low frequency region under 300 Hz, it becomes more sensitive in the case that the ear canal was filled with the water by removing the air bubble.
The reverse phenomenon of "hearing" at about 300 Hz is explained by difference between frequency characteristics of the occlusion effect (air conduction) and the effect in which the ear canal was filled with the water (bone conduction).
倉本 和興,老松 建成, 桑原 信也, 山口 静馬 11(81)
合成開口ソーナーの基礎研究と水槽実験の結果
Basic Study of Synthetic Aperture Sonar and Experimental Results at Acoustic Tank
*1 Takao SAWA (Japan Marine Science and Technology Center)
*2 Sadaaki SATO (Kawasaki Shipbuilding Corporation)
*3 Toshiaki NAKAMURA (National Defense Academy in Japan)
*4 Takuya SHIMURA, Yasutaka AMITANI, Hiroshi OCHI, Yoshitaka WATANABE, Satoshi TSUKIOKA (Japan Marine Science and Technology Center)
Abstract:
Synthetic Aperture Sonar has a great advantage of high azimuth resolution compared with legacy side scan sonar. Calculating theoretical resolution of Synthetic Aperture Sonar, it needs approximations and limitations to express that as elementary mathematics. In this study, we discuss an influence on resolution by these mathematical approximations and limitations. We had made a trial Synthetic Aperture Sonar to study basic characters both of theory and experiment. As a result of our experiment at acoustic tank, it is turn out that resolutions on experiment, simulation and theory are same. And we discuss about conditions to achieve theoretical resolutions at sea area.
澤  隆雄,佐藤 禎章, 中村 敏明, 志村 拓也,網谷 泰孝,越智  寛, 渡邊 佳孝, 月岡  哲 16(86)
解説 我が国のソーナーの音響標準について 三上 宏幸 24(94)
イルカに吸盤でハイドロホンを取り付けよ-ハイテクはローテクな技が支える- 赤松 友成 29(99)
2003年度第1回シンポジウム発表要旨 イルカの音響行動の観察システム-音響データロガーの開発- 赤松 友成,王  丁, 王  克雄 41(111)
ADCPを用いた海潮流の測定と水産への応用 三宅 秀男,高橋 大介 44(114)
随想 わが国古来の技術文化を想う 新美 博一 48(118)
海外学会カレンダー 山口  功 51(121)
会記事 55(125)