Particle size effect on the saturation of methane hydrate in sediments – Constrained from experimental results     

Hailong Lu  Tatsuji Kawasaki  Toshiyasu Ukita  Igor Moudrakovski  Tetsuya Fujii  Satoshi Noguchi  Tadaaki Shimada  Masaru Nakamizu  John Ripmeester  Chris Ratcliffe 《Marine and Petroleum Geology》2011,28(10):1801-1805

Except for those occurring at seafloor, most of natural gas hydrate form in sediments and are subject to the influence of sediment. Among these factors, the particle size effect on hydrate saturation level in sediment have been studied with a series of silica sands with various sizes, and the results obtained clearly indicate that particle size does play an important role in affecting the saturation level of hydrate in sediments. The proton relaxation times of water confined in the same series of silica sands, which were determined with NMR measurement, show logarithmic relationship with particle size. By comprehensive consideration of the results of hydrate saturation and water proton relaxation times, the particle size effect observed is tentatively explained by the water availability for hydrate formation in sediments.  相似文献   

Study of variable stars in the MOA data base: long-period red variables in the Large Magellanic Cloud – II. Multiplicity of the period–luminosity relation     

S. Noda  M. Takeuti  F. Abe  I. A. Bond  R. J. Dodd  J. B. Hearnshaw  M. Honda  M. Honma  J. Jugaku  Y. Kan-ya  Y. Kato  P. M. Kilmartin  Y. Matsubara  K. Masuda  Y. Muraki  T. Nakamura  K. Ohnishi  M. Reid  N. J. Rattenbury  To. Saito  Y. Saito  H. Sato  M. Sekiguchi  J. Skuljan  D. J. Sullivan  T. Sumi  R. Yamada  T. Yanagisawa  P. C. M. Yock  M. Yoshizawa 《Monthly notices of the Royal Astronomical Society》2004,348(4):1120-1134

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Constraining the location of microlensing objects towards the Large Magellanic Cloud through parallax measurement in EAGLE observations     

T. Sumi  Y. Kan-ya 《Monthly notices of the Royal Astronomical Society》2002,337(3):1017-1026

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Pulsation at the tip of the first giant branch?     

Yoshifusa Ita  Toshihiko Tanabé  Noriyuki Matsunaga  Yasushi Nakajima  Chie Nagashima  Takahiro Nagayama  Daisuke Kato  Mikio Kurita  Tetsuya Nagata  Shuji Sato  Motohide Tamura  Hidehiko Nakaya  Yoshikazu Nakada 《Monthly notices of the Royal Astronomical Society》2002,337(3):L31-L34

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Proper motion dispersions of red clump giants in the galactic bulge: observations and model comparisons     

Nicholas J. Rattenbury  Shude Mao  Victor P. Debattista  Takahiro Sumi  Ortwin Gerhard  Flavio De Lorenzi 《Monthly notices of the Royal Astronomical Society》2007,378(3):1165-1176

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Spatial inhomogeneity of the martian subsurface water distribution: implication from a global water cycle model     

Tetsuya Tokano 《Icarus》2003,164(1):50-78

In an effort to test and to understand the global hydrogen distribution in the shallow subsurface of Mars retrieved by the Mars Odyssey gamma-ray spectrometer, the present state and movement of water are investigated by a coupled global subsurface-atmosphere water cycle model. It was found that the observed global subsurface hydrogen distribution is largely consistent with the modeled global water cycle, so a large fraction of hydrogen is likely to exist as water, at low and mid latitudes in the form of adsorbed water. Under the present climate the water content in the shallow subsurface becomes higher in the northern hemisphere than in the southern hemisphere as a result of global water cycle, regardless of the initial water distribution in the soil or adsorptive capacity. The higher annual maximum soil temperature in the south, stronger net northward transport of atmospheric water vapor, and the emission of vapor from the northern residual polar cap in northern summer contribute to this hemispheric asymmetry. The generally higher adsorptive capacity of clay minerals in the northern plains may further increase this bias. The longitudinal inhomogeneity is caused by several factors, such as thermal inertia, adsorptive capacity, and atmospheric surface pressure. The water abundance is locally high in low thermal inertia regions (e.g., Arabia Terra) and at deep places where the surface pressure is high (e.g., Hellas); it is low in soil with a low adsorptive capacity (e.g., Tharsis) and high thermal inertia regions (e.g., Solis Planum). Most of the soil humidity near the surface at low and mid latitudes may originate from the atmosphere. The model implies that the upper soil layer should be largely ice-free because otherwise an excessive sublimation and vapor emission into the atmosphere in warm seasons would violate the observational constraints. Moreover, the more uniform latitudinal variation of the observed hydrogen abundance near the surface compared to that of deeper layers is indicative of the presence of adsorbed water instead of ground ice because the adsorbed water content does not as steeply depend on latitude as the ground ice stability. Concerning the regolith mineralogy, montmorillonite can much better account for the observed water cycle than palagonite. While the presence of permanent ground ice appears likely in the polar region below a thin layer, large seasonal cycle of phase change between pore ice and adsorbed water may be possible. Regolith adsorption/desorption is neither negligible nor crucial for the seasonal atmospheric water cycle, but the surface-atmosphere coupling is a major prerequisite for the long-term evolution of subsurface water distribution.  相似文献   

An optical and near-infrared search for brown dwarfs in the Pleiades cluster     

Chie Nagashima †  Paul D. Dobbie  Takahiro Nagayama  Yasushi Nakajima  Tetsuya Nagata  Motohide Tamura  Tadashi Nakajima  Koji Sugitani  Hidehiko Nakaya  Simon T. Hodgkin  rew J. Pickles  Shuji Sato 《Monthly notices of the Royal Astronomical Society》2003,343(4):1263-1270

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Variable stars in the Magellanic Clouds: results from OGLE and SIRIUS     

Yoshifusa Ita  Toshihiko Tanabé  Noriyuki Matsunaga  Yasushi Nakajima  Chie Nagashima  Takahiro Nagayama  Daisuke Kato  Mikio Kurita  Tetsuya Nagata  Shuji Sato  Motohide Tamura  Hidehiko Nakaya  Yoshikazu Nakada 《Monthly notices of the Royal Astronomical Society》2004,347(3):720-728

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Timing of dextral oblique subduction along the eastern margin of the Asian continent in the Late Cretaceous: Evidence from the accretionary complex of the Shimanto Belt in the Kii Peninsula, Southwest Japan   总被引：1，自引：1，他引：0  

Tetsuya  Tokiwa 《Island Arc》2009,18(2):306-319

Paleomagnetic studies and hotspot track analyses show that the Kula Plate was subducted dextrally with respect to the Eurasian Plate from the Coniacian to Campanian. However, geological evidence for dextral subduction of the Kula Plate has not been reported from Southwest Japan. Studies of the Coniacian to lower Campanian Miyama Formation of the Shimanto Belt reveal that the mélange fabrics show a dextral sense of shear both at outcrop and microscopic scales. In addition, thrust systems at map-scale also show dextral shearing. Restored shear directions in the mélange indicate dextral oblique subduction of an oceanic plate. This indicates that the Kula Plate subducted dextrally along the eastern margin of Asia during the Coniacian to early Campanian. Combinations with other published kinematic and age constraints suggest that Southwest Japan experienced a change from sinistral to dextral and back to sinistral shear between 89–76 Ma. This history is compatible with global-scale plate reconstructions and places good constraints on the timing of plate boundary interaction with the Cretaceous East Asian margin.  相似文献   

Characteristic features in Venus’ nightside cloud-top temperature obtained by Akatsuki/LIR     

Makoto Taguchi  Tetsuya Fukuhara  Masahiko Futaguchi  Mitsuteru Sato  Takeshi Imamura  Kazuaki Mitsuyama  Masato Nakamura  Munetaka Ueno  Makoto Suzuki  Naomoto Iwagami  George L. Hashimoto 《Icarus》2012,219(1):502-504

Mid-infrared images of almost the entire Venus nightside hemisphere obtained by the Longwave Infrared Camera (LIR) onboard Akatsuki on December 9 and 10, 2010 reveal that the brightness temperature of the cloud-top ranges from 237 K in the cold polar collars to 243 K in the equatorial region, significantly higher than the values obtained by Venera 15. Other characteristic features of the temperature distributions observed are zonal belt structures seen in the middle and low latitudes and patchy temperature structures or quasi-periodic streaks extending in a north–south direction in the northern middle latitudes and southern low latitudes.  相似文献