1 0 0 0 OA 新潟積成盆地における西山・灰爪累層,魚沼層群の層序と古環境
1 0 0 0 IR 宍道湖産ヤマトシジミ殻体の微細成長縞の観察
- 著者
- 高安 克已 小林 巖雄 森田 浩史
- 出版者
- 島根大学
- 雑誌
- Laguna : 汽水域研究 (ISSN:13403834)
- 巻号頁・発行日
- vol.3, pp.103-110, 1996-03
- 被引用文献数
- 2
A vital marking experiment was carried out to examine the process of micro-growth striations of Corbicula japonica Prime from Lake Shinji. Samples were cultured in aquarium and in Lake Shinji for about one month. During culturing they were marked two to three times by tetracycline hydrochloride solution. The fluorescent lines showing the time of marking are observed remarkably well, especially in the samples marked during day time. In addition to these lines, strong stress bands are observed in whole samples in concurrence with the markings. This fact suggests that the process of marking experiment itself arrested the growth of shell. The pattern of micro-growth striations in between the marked lines of each sample show neither cyclicity nor regularity. 13; On the other hand, the micro-growth striations in the samples cultured in Lake Shinji show tendency of higher frequency per day than those in aquarium. From these results, the formation of micro-growth striations is assumed to be influenced by complex changes in the brackish-water environments as well as by their physiological rhythm and its individual variation. 13;
- 著者
- 堀 光平 林 巖
- 出版者
- 一般社団法人日本機械学会
- 雑誌
- 日本機械学會論文集. C編 (ISSN:03875024)
- 巻号頁・発行日
- vol.62, no.596, pp.1548-1555, 1996-04-25
- 被引用文献数
- 6
To improve the efficiency of 3K-type mechanical paradox planetary gear drive, a new design method called the approach-and recess-contact ratio equalization method is proposed and described. The concept of this method is to satisfy the coaxial condition of the rotatory- and fixed-internal gear pairs, which have a large influence on the efficiency of the gear drive, and simultaneously to maximize their efficiency. For this purpose, first the contact ratios of the two internal gear pairs are given ; second, their profile-shift coefficients are determined so that the coaxial condition can be satisfied ; then, the diameters of their addendum circles are determined so that their approach- and recess-contact ratios can be equalized. The efficiency of the gear drive obtained by this design method is theoretically calculated under the assumption that the tooth surface frictional coefficients are all 0.1. Consequently, the maximum efficiency of 86.1% is obtained on a gear drive with a reduction ratio of 1/351 and a contact ratio of 1.2. This obtained efficiency is higher by 12% and 8% than the efficiencies of 74% and 78%, obtained by the conventional design method without and with profile-shift coefficient optimization, respectively.
- 著者
- 稲垣 洋輔 香川 美仁 森川 広一 岩附 信行 林 巖 細川 俊之
- 出版者
- 一般社団法人日本機械学会
- 雑誌
- Dynamics and Design Conference : 機械力学・計測制御講演論文集 : D & D (ISSN:13480235)
- 巻号頁・発行日
- vol.2000, 2000-09-01
This paper describes the optimization of the case cover of small hard disk drive (HDD) used for personal computers. Small Hard disk drives are one of the main causes of noise radiated from personal computers or workstations. Nowadays the rotational speed of spindle motor used to rotate disks is increased year by year in order to increase the transfer speed. It is afraid that the noise radiated from small HDD is increasing more and more accordingly. Optimization of the shape of ribs which are attached on the case cover are hence tried in order to reduce the noise radiated from small HDD used for personal computers. Firstly, the natural modes of flexural vibration of the case covers of small HDD, which were made of aluminum, steel, and brass, were experimentally determined, and the natural frequencies, mode shapes, and damping coefficients were determined. Secondly, the sound power radiated from the case covers was theoretically estimated dy using the results of FEM modal analysis, was made sure to coincide with the measured values. Finally, the sound powers radiated when the thickness of the case cover was uniformly thickened, and when radial ribs, lattics ribs, or circular ribs were attached on the case cover, were compared. As the results, it has been revealed that the sound power is more reduced as the thickness is increased, the increase of thickness is effective especially to the low modes. For attaching ribs, radial ribs were most effective, and the sound power was more reduced as the number of ribs and/or the height was increased.