The H i content of star-forming galaxies at z= 0.24     

Philip Lah  Jayaram N. Chengalur  Frank H. Briggs  Matthew Colless  Roberto De Propris  Michael B. Pracy  W. J. G. de Blok  Shinobu S. Fujita  Masaru Ajiki  Yasuhiro Shioya  Tohru Nagao  Takashi Murayama  Yoshiaki Taniguchi  Masafumi Yagi  Sadanori Okamura 《Monthly notices of the Royal Astronomical Society》2007,376(3):1357-1366

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Analbite → monalbite transition in a heat treated twinned amelia albite     

Fujio P. Okamura  Subrata Ghose 《Contributions to Mineralogy and Petrology》1975,50(3):211-216

Amelia albite annealed at > 1080 °C for 3200 hrs by Duba and Piwinskii (1974) shows very fine twin lamellae (～1 μm) after the albite law, suggesting that it once underwent transformation into monalbite. A fragment of this specimen was investigated at 27 °C, 300 °C, 550 °C, 800 °C and 930 °C using the high-temperature precession technique. As the temperature increases, the splitting angle of c ^*-axes (likewise c ^*-axes) of two twin individuals continues to decrease. The photographs taken at 930 °C show that these two splitting angles have converged to 0^o, indicating completion of the transformation into monalbite. The transition point we observe supports the results of MacKenzie (1952) (920±20 °C) and Grundy et al. (1967) (930 °C) rather than those of Sueno et al. (1973) and Prewitt et al. (1974) (> 1080 °C); the discrepancy is most likely due to the differences in the degree of Al-Si disorder of the samples used in the experiments.  相似文献   

Liquefied soil pressures on vertical walls with adjacent embankments     

M. Okamura  M. Ishihara  K. Tamura 《Soil Dynamics and Earthquake Engineering》2006,26(2-4):265-274

Horizontal earth pressures on rigid vertical walls in liquefied soils have extensively been studied by many researchers for the level ground surface condition. In this paper, a series of centrifuge tests was conducted to investigate the effects of embankments resting on ground surfaces on the pressure on the rigid vertical walls. In the tests, earth pressures on the rigid walls were successfully measured with built-in earth pressure cells with small accelerometers attached on them. The earth pressure cells are capable of measuring both normal and shear stresses simultaneously with a good accuracy. It appears that dynamic component of the earth pressure of liquefied sand is in proportion to the acceleration of the rigid wall irrespective of amplitude and frequency of the input motion, and increases with increasing average embankment load. On the other hand, the residual component of the earth pressure is found to be well estimated from FEM assuming the liquefied soil as an incompressible elastic body. A practical formula of the earth pressures is established for the purpose of practical use.Another series of centrifuge tests was carried out on models with solidification or densification zones below embankment toes as a remedial countermeasure against liquefaction-induced embankment failure. It was found that the proposed formulae holds valid independently of the movement of walls as long as the liquefied soil behaves as a heavy fluid, and the countermeasure does not soften significantly.  相似文献   

Unstable forearc stress in the eastern Nankai subduction zone for the last 2 million years     

A. Yamaji  T. Sakai  K. Arai  Y. Okamura 《Tectonophysics》2003,369(1-2):103-120

Transpressional tectonics characterizes the SW Japan arc. However, we will show in this article that offshore seismic profiles and onshore mesoscale faults indicate that the eastern part of the forearc was subject to transtensional tectonics since ca. 2.0 Ma. Offshore normal faults imaged on the profiles run parallel to the Nankai Trough, and started activity at 1.0 Ma, but transtensional tectonics commenced the onshore area earlier. In order to understand the stress history in the forearc region, we collected fault-slip data from onshore mesoscale faults in Plio-Pleistocene sedimentary rocks in the Kakegawa area at the northeastern extension of the offshore normal faults. Most of the mesoscale faults are oblique-normal, indicating that the area was subject to transtensional tectonics. The faults suggest that the compressional tectonic regime was followed by the transtensional one at 2.0 Ma, in agreement with regional tectonostratigraphic data, which indicate that folding ceased at that time. Present compressional stress followed the transtensional tectonic regime sometime in the late Pleistocene. Transtensional or extensional tectonic zone shifted from the Kakegawa area to the offshore region.These observations indicate that the state of stress just behind the accretionary prism of the eastern Nankai subduction zone has been unstable in the last 2 million years, suggesting that the forearc wedge has been at critical state in that gravitational force and basal shear traction on the wedge have been balanced, but the forearc tectonics has been susceptible to small perturbations. Possible factors compatible with the observed stress history include the change of subduction direction of the plate at 1.0 Ma, and the rapid uplift of Central Japan thereafter.  相似文献   

Discovery of a large-scale clumpy structure around the Lynx supercluster at z∼ 1.27     

Fumiaki Nakata  Tadayuki Kodama  Kazuhiro Shimasaku  Mamoru Doi  Hisanori Furusawa  Masaru Hamabe  Masahiko Kimura  Yutaka Komiyama  Satoshi Miyazaki  Sadanori Okamura  Masami Ouchi †  Maki Sekiguchi  Yoshihiro Ueda  Masafumi Yagi  Naoki Yasuda 《Monthly notices of the Royal Astronomical Society》2005,357(4):1357-1362

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Optical instruments for JNLT     

Sadanori Okamura 《Astrophysics and Space Science》1989,160(1-2):297-311

The plan for optical instruments for the Japanese National Large Telescope is described. Performance of the first-generation instruments is computed on the basis of tentative designs, and the capability of the telescope is demonstrated.Paper presented at the Symposium on the JNLT and Related Engineering Developments, Tokyo, November 29–December 2, 1988.  相似文献   

The build-up of the colour–magnitude relation as a function of environment     

Masayuki Tanaka  Tadayuki Kodama  Nobuo Arimoto  Sadanori Okamura  Keiichi Umetsu  Kazuhiro Shimasaku  Ichi Tanaka  Toru Yamada 《Monthly notices of the Royal Astronomical Society》2005,362(1):268-288

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Evolution of the colour–radius and morphology–radius relations in SDSS galaxy clusters     

Tomotsugu Goto †  Masafumi Yagi  Masayuki Tanaka  Sadanori Okamura 《Monthly notices of the Royal Astronomical Society》2004,348(2):515-518

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Surface color photometry of five barred spiral galaxies     

Sadanori Okamura  Bunshiro Takase 《Astrophysics and Space Science》1976,41(2):275-285

Distributions of the surface brightness and the surface color of five barred spiral galaxies expressed in the form of digital maps are presented. This is the first step to determine the composition of the components of barred spiral galaxies — bar, spiral arm, inner ring and outer ring — and to obtain an accurate picture of the dynamical model of a barred spiral galaxy. We have found that (a) the bar is redder than the spiral arm and has a color similar to that of the disk and (b) the inner ring of theSB(r) type galaxy is bluer than the bar and rather resembles the spiral arm.  相似文献   

Effects of new antifouling compounds on the development of sea urchin   总被引：5，自引：0，他引：5  

Kobayashi N  Okamura H 《Marine pollution bulletin》2002,44(8):748-751

Tributyltin oxide (TBTO) has been used worldwide in marine antifouling paints as a biocide for some time. However, it produced toxic effects, especially in marine water/sediment ecosystems. Consequently, its use in antifouling paints has been prohibited in many countries. In this study, the toxicity of alternative and/or new antifouling biocides compared with TBTO is assessed by a biological method. The effects of these chemicals on marine species have not been well studied. This paper assesses, comparatively, the effects of eight biocides on sea urchin eggs and embryos. The chemicals assessed were TBTO, Irgarol 1051, M1 (the persistent degradation product of Irgarol), Diuron, zinc pyrithione, 'KH101', 'Sea-Nine 211', and copper pyrithione. For these chemicals, toxicity appears to be in the order zinc pyrithione > Sea-Nine 211 > KH101 > copper pyrithione > TBTO > Diuron approximately = Irgarol 1051 > M1. Here, we show that zinc pyrithione, Sea-Nine 211, KH101, and copper pyrithione are much more toxic to sea urchins than TBTO or the other chemicals.  相似文献