著者

小泉 雄大 田城 文人

出版者

一般社団法人 日本魚類学会

雑誌

魚類学雑誌 (ISSN:00215090)

巻号頁・発行日

pp.20-021, (Released:2020-09-10)

参考文献数

17

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A single large specimen [197.8 mm standard length (SL)] of the genus Chaunax Lowe, 1846 (Lophiiformes: Chaunacidae), captured during a commercial bottom trawl at a depth of 150–250 m off Cape Daio-zaki, Shima, Mie Prefecture, Japan on November 2016. Lacked markings on the body surface, thereby differing clearly from the three Japanese congeners (Chaunax fimbriatus Hilgendorf, 1879, Chaunax penicillatus McCulloch, 1915 and Chaunax abei Le Danois, 1978) known to date. Subsequently identified as Chaunax apus Lloyd, 1909, the specimen was characterized as follows: body without marking, reddish dorsally and paler ventrally (fresh condition), becoming uniformly whitish (preserved) ; tips of cirri on esca partially dark; dorsal surface of head lacking cirri; head length 39.3% SL; and 3 neuromasts in upper preopercular series, 3 in lower preopercular series, and 15 in pectoral series. The specimen represents both the northernmost and easternmost records of the species in the Pacific Ocean, in addition to being the first from Japanese waters. Intraspecific variation was noted in the count of spinules bridging the lateral-line complex (4–5 pairs in the present specimen vs. usually 3 pairs in previous reports of the species). The need for reconsideration of two of the three species groups recognized in the genus Chaunax [C. abei (including C. apus) and C. fimbriatus species groups] was discussed from the viewpoint of new morphological data obtained from the above specimen. The new standard Japanese name “Akafusen” is proposed for C. apus, in referring to its characteristic body shape and color.

著者

小泉 雄大 遠藤 広光 今村 央

出版者

一般社団法人 日本魚類学会

雑誌

魚類学雑誌 (ISSN:00215090)

巻号頁・発行日

pp.20-029, (Released:2021-03-15)

参考文献数

17

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The stomiid snaggletooth genus Astronesthes Richardson, 1844 comprises nine species groups (including 40 valid species), plus a further eight species independent of the groups. Among them, the Astronesthes cyanea species group (seven species) is distinguished from all other species by having the following characters: e.g., 42‒50 total vertebrae, 16‒21 dorsal-fin rays, a relatively long chin barbel (but rudimentary in three species), 3 or 4 photophores (part of the ventral row below the pectoral fin) forming an arch, and prominent luminous tissue on the operculum in large specimens. Two specimens (84.6 and 111.1 mm in standard length) belonging to this species group, collected off the Yaeyama and Ogasawara Islands, Japan, were identified as Astronesthes formosana Liao, Chen and Shao, 2006. Although the original description of A. formosana, which noted its close resemblance to Astronesthes indopacifica Parin and Borodulina, 1997, considered the former to differ from the latter in having prominent luminous patch on the lower jaw (vs. absent), a slightly swollen or rounded tip on the chin barbel (vs. slender and simple), prominent luminous tissue on the lower part of the operculum, extending to the lower end of the maxilla [vs. restricted to the middle part of the operculum (in >50 mm standard length specimens)], numerous scalelike spots or prominent patches dorsally on the head and body (vs. sparse), and the upper nostril with more a pair prominent or smearlike luminous patches (vs. a single pair prominent luminous patches), no significant differences were found between the two species in prominent luminous tissue on the operculum, and scalelike spots or prominent patches dorsally on the head (including upper nostril) and body. In addition, the barbel tip shape was found to be of inconclusive value for separating the two species, leaving the presence or absence of prominent luminous patch on the lower jaw as the only valid distinguishing characteristic. Because the features of the two Japanese specimens agreed closely with those in the original description of A. formosana, they were identified as that species, being the first record of the latter from Japanese waters. The new standard Japanese name “Taiwan-tokagegisu” is proposed for the species.

著者

中村 元 福江 高志 小泉 雄大 石塚 勝

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 B編 (ISSN:03875016)

巻号頁・発行日

vol.76, no.768, pp.1184-1190, 2010-08-25 (Released:2017-06-09)

参考文献数

8

被引用文献数

4 2

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A compact air-cooling device often encounters high-density mounting environment, which may reduce a flow-rate of a cooling fan. In this work, the PQ characteristics of a cooling fan was investigated which varied by placing an obstacle in close proximity of a fan. Small axial-flow fans of 30-80mm in side length and small centrifugal fans of 35-52mm in side length were tested here. As a result, it was found that the maximum flow rate for the free air-flow begin to decrease when the opening area of the gap-flow between the fan and the obstacle becomes smaller than twice the fan flow area, and decreases suddenly if it becomes smaller than the fan flow area. This relation was almost independent of type and size of a fan, rotation speed of impeller, and shape and position of an obstacle.

著者

福田 哲士 増田 幸男 福江 高志 畠山 友行 石塚 勝 小泉 雄大

出版者

社団法人 日本伝熱学会

雑誌

日本伝熱学会論文集 (ISSN:09189963)

巻号頁・発行日

vol.30, no.1, pp.1-12, 2022 (Released:2022-02-22)

参考文献数

21

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This study describes the 40 mm scale small axial fan P - Q curves mounted in high-density packaging electronic equipment. An accurate prediction of supply flow rate by fans strongly affects the reliability of the cooling design. However, in high-density packaging electronic equipment, the fan performance is affected by the mounting components around the fans, and the accurate prediction of the supply flow rate becomes difficult. In this paper, by a CFD analysis, visualization around the fan impellers with the obstructions was conducted. By comparing the predicted result of the P- Q curves by the proposed analytical method and experiment, the proposed analysis's effectiveness was evaluated.