Photometric study of new southern SU UMa-type dwarf novae and candidates: V877 Ara, KK Tel and PU CMa     

Taichi Kato  Roland Santallo  Greg Bolt  Tom Richards  Peter Nelson  Berto Monard  Makoto Uemura  Seiichiro Kiyota  Rod Stubbings  rew Pearce  Tsutomu Watanabe  Patrick Schmeer  Hitoshi Yamaoka 《Monthly notices of the Royal Astronomical Society》2003,339(3):861-871

  相似文献   

Photo-inhibition of phytoplankton photosynthesis as a function of exposure time     

Masayuki Takahashi  Sooji Shimura  Yukuya Yamaguchi  Yoshihiko Fujita 《Journal of Oceanography》1971,27(2):43-50

The photo-inhibition of phytoplankton photosynthesis at higher intensities was examined with a cultured marine diatom,Phaeodactylum tricornutum, and natural samples. The question was to determine whether photo-inhibition results from excretion of photosynthetic products from cell or from an actual decrease in photosynthetic rate. P. tricornutum cultured at 15 klux showed very little photo-inhibition up to 70 klux, and, in the sample cultured at 1 klux, most marked photo-inhibition was observed in 3 hours experiment. Extracellular release was less than 30% of particulate fixation, and did not show any extreme increase to supplement photosynthesis depression at higher light intensities. When the photosynthesis was measured during 10 minutes, both samples showed no photo-inhibition. The photosynthesis by low light sample lost the linearity of time-course with prolonged exposure at high light intensity. Observed photo-inhibition, therefore, we explained with the actual decrease in photosynthetic rate. Similar photo-inhibition could be seen in marine phytoplankton samples concentrated by filtration.  相似文献   

Photographic observations of the stalked crinoidMetacrinus rotundus carpenter in Suruga Bay,central Japan     

Toshihiko Fujita  Suguru Ohta  Tatsuo Oji 《Journal of Oceanography》1987,43(6):333-343

Photographic observations were carried out at depths of the shelf edge at the mouth of Uchiura Inlet, Suruga Bay, central Japan in order to clarify the life style of the isocrinid stalked crinoid,Metacrinus rotundus (Echinodermata). The distribution of the species was found to be restricted to a narrow area where boulders and rock outcrops were locally present. Mean density of the crinoid was 0.05 m^–2, and this value was an order of magnitude smaller than that of the deeper isocrinid,Diplocrinus wyvillethomsoni, reported from the Bay of Biscay.Metacrinus rotundus formed a parabolic filtration fan with its arms recurved into the bottom current, and was thought to be a passive suspension feeder elevating the fan into the water column by its stalk. The distal half of the stalk lay along the hard substratum and about ten groups of cirri grasped the substratum. This mode of attachment was similar to that ofCenocrinus rather than that ofDiplocrinus. Metacrinus rotundus collect food at the layer between 10 and 50 cm above the sea floor, and do not utilize a higher layer even when this layer could be utilized by climbing over a larger boulder. Resuspended benthic materials are thought to be important as a food source forM. rotundus, and the crinoids seek not only locations of stronger currents but also the position where much resuspended matter is available.  相似文献   

II-3 Full-scale performance tests on tandem wells turbine     

Yukihisa Washio  Hitoshi Hotta  Takeaki Miyazaki  Yoshio Masuda 《Ocean Engineering》1985,12(6):564

  相似文献   

An energy conversion method in the ocean using the density difference of water     

Hitoshi Mochizuki  Wataru Mitsuhashi 《Ocean Engineering》1981,8(1):91-96

A new method which produces energy from the ocean by utilizing the density difference of water, by means of a “chimney effect”, is proposed. Density difference of water in the ocean occurs in two ways, namely differences of consistency and water temperature. For instance, fresh river and melting floes and icebergs are pointed out as some origins of the former, while thermal effects of volcanoes and hot springs may account for the latter. Furthermore, sunlight power transmitted into the sea through glass fibre power lines can be an artificial source in the latter case.This paper concentrates on regions near estuaries where low density river water can be piped into the high density ocean. An analysis estimates that the proposed method extracts energy of several thousands or more kW in the above case.  相似文献   

Full-range equation for wave boundary layer thickness     

Ahmad Sana  Hitoshi Tanaka 《Coastal Engineering》2007

Full-range equation covering all the flow regimes in a wave boundary layer is proposed for the boundary layer thickness. The results are compared with the available experimental data and good agreement has been found. In case of wave boundary layers, there are three definitions of boundary layer thickness in use. Therefore, the full-range equation is derived for three of the definitions. The findings of this study may be useful in calculating suspended sediment transport in coastal environments and studying wave–current combined motion.  相似文献   

Air-Sea Gas Transfer Velocity in Stormy Winter Estimated from Radon Deficiency     

Hitoshi Kawabata  Hisashi Narita  Koh Harada  Shizuo Tsunogai  Masashi Kusakabe 《Journal of Oceanography》2003,59(5):651-661

Thirteen vertical profiles of ²²⁶Ra and ²²²Rn in the near-surface water were obtained in the western North Pacific in winter, and the gas transfer velocities across the air-sea interface were estimated. The transfer velocities found by applying a steady state model varied widely from 2.1 to 30.2 m day⁻¹ with a mean of 9.4 m day⁻¹. The mean value is almost 5 times higher than that in summer in other oceans, and the maximum value is a record high for world oceans. This is partly due to the inadequacy of the steady state model, which overestimates when stronger winds blow in more recent days than the ²²²Rn half-life of about 4 days. In fact, a strong low pressure zone passed through the station about 2 days earlier, which was one of the low pressure zones that with a period of develop once a week or so in the northwestern North Pacific in winter. Instead of steady-state removal, if half of the radon removal occurred sporadically every 7 days, and the last removal took place two days before the observation, the transfer velocity would be 26 m day⁻¹. Our mean transfer velocity, which is less than 20% different from the steady state value including both overestimated and underestimated values, 9.4 ± 4.8 m day⁻¹, seems to represent the mean state of this region in winter. This suggests that the gas exchange fluxes under extremely rough conditions in the open ocean are larger than those estimated by using a transfer velocity equation with a linear or quadratic relationship with wind speed. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Upwelling plumes in sagami bay and adjacent water around the Izu Islands,Japan     

Masayuki Takahashi  Isao Koike  Takashi Ishimaru  Toshiro Saino  Ken Furuya  Yoshihiko Fujita  Akihiko Hattori  Shun-ei Ichimura 《Journal of Oceanography》1980,36(4):209-216

Water plumes, 20 km long or less, identified by low temperature, high salinity and high nutrient concentrations, were observed on the eastern side of Izu Islands where the Kuroshio Current or its branch flowed eastward. The T-S diagrams and the vertical profiles of oceanographic variables indicated that the water plumes resulted from the upwelling of subsurface water. A newly formed plume, characterized by a sharp temperature front and high nutrient concentrations, contained less chlorophyll than did old plumes. It is suggested that the upwelling plumes are maintained for a period long enough to allow luxuriant growth of phytoplankton.  相似文献   

Density,biomass and community structure of demersal fishes off the Pacific coast of northeastern Japan   总被引：8，自引：0，他引：8  

Toshihiko Fujita  Tadashi Inada  Yoshio Ishito 《Journal of Oceanography》1993,49(2):211-229

Demersal fish communities were studied on the lower continental shelf and the upper continental slope along the Pacific coast of northeastern Japan. Species composition, number and weight of each species were examined based on otter trawl samples at 45 stations. Mean density and biomass of demersal fishes were 131 ha^–1 and 21 kg ha^–1, respectively. The ten most abundant species comprised of about 95% of total number and weight of overall catch indicating simple species composition. Gadiform fishesTheragra chalcogramma, Gadus macrocephalus andPhysiculus maximowiczi were the most important species by number, weight and frequency of occurrences, and three main community types represented by the three key species were recognized.Theragra-dominant community showed higher density and biomass, and lower diversity thanPhysiculus-dominant community did. Species diversity of demersal fish community was negatively correlated to density and biomass. Density and biomass of demersal fish community were high on the uppermost slope, and the high abundance resulted from low-diversity communities dominated byT. chalcogramma andG. macrocephalus.  相似文献   

IMA Kobe 2006 Special Issue: Sea-floor Hydrothermal Deposits of Arc–Back-arc Systems in Western Pacific     

Tetsuro Urabe    Hitoshi Chiba  Yasuhiro Kato 《Resource Geology》2008,58(3):205-205

  相似文献