Asymptotic giant branch superwind speed at low metallicity     

Jonathan R. Marshall  Jacco Th. van Loon  Mikako Matsuura  Peter R. Wood  Albert A. Zijlstra  Patricia A. Whitelock 《Monthly notices of the Royal Astronomical Society》2004,355(4):1348-1360

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Microwave observations of Saturn's rings: anisotropy in directly transmitted and scattered saturnian thermal emission     

David E. Dunn  Lawrence A. Molnar  Imke de Pater 《Icarus》2004,171(1):183-198

We present a new Very Large Array (VLA) image of Saturn, made from data taken in October 1998 at a wavelength of λ3.6 cm. The moderate ring opening angle (B≈15°) allows us to explore direct transmission of microwave photons through the A and C rings. We find a strong asymmetry of photons transmitted through the A ring, but not in the C ring, a new diagnostic of wake structure in the ring particles. We also find a weak asymmetry between east and west for the far side of the ansae. To facilitate quantitative comparison between dynamic models of the A ring and radio observations, we extend our Monte Carlo radiative transfer code (described in Dunn et al., 2002, Icarus 160, 132-160) to include idealized wakes. We show the idealized model can reproduce the properties of dynamic simulations in directly transmitted light. We examine the model behavior in directly transmitted and scattered light over a range of physical and geometric wake parameters. Finally, we present a wake model with a plausible set of physical parameters that quantitatively reproduces the observed intensity and asymmetry of the A ring both across the planet and in the ansae.  相似文献   

Fragmentation and the formation of primordial protostars: the possible role of collision-induced emission     

E. Ripamonti  T. Abel 《Monthly notices of the Royal Astronomical Society》2004,348(3):1019-1034

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The dependence of protoplanet migration rates on co-orbital torques     

G. D'Angelo  M. R. Bate  S. H. Lubow 《Monthly notices of the Royal Astronomical Society》2005,358(2):316-332

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X-shaped radio galaxies as observational evidence for the interaction of supermassive binary black holes and accretion disc at parsec scale     

F. K. Liu 《Monthly notices of the Royal Astronomical Society》2004,347(4):1357-1369

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Rapid climatic changes recorded in loess successions     

J. Vandenberghe  G. Nugteren 《Global and Planetary Change》2001,28(1-4)

Detailed grain-size analyses, both in China and western Europe, indicate the occurrence of short climatic cycles during loess deposition of the last glacial. Cold episodes coincided with enhanced deposition of relatively coarse loess and alternated with relatively warmer episodes with decreased deposition of finer loess and soil formation. In Europe, these oscillations may coincide with alternations of permafrost development and degradation. The short-term climatic events in the loess sections are similar to the Dansgaard–Oeschger events in ice-core records.  相似文献   

UBV RI CCD photometric study of the open clusters Basel 4 and NGC 7067     

R. K. S. Yadav  Ram Sagar 《Monthly notices of the Royal Astronomical Society》2004,349(4):1481-1492

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The exchange of organic carbon in basin mangrove forests in a southwest Florida estuary     

Robert R. Twilley 《Estuarine, Coastal and Shelf Science》1985,20(5):543-557

The magnitude and seasonality of organic carbon exchange was estimated for two basin mangrove forests in Rookery Bay, Florida. Runoff and tidal inundation in the forests were seasonal with half the annual total of each occurring from August to October. In each forest there were 152 tides yr^?1 with a cumulative depth of about 12 m. Total organic carbon increased in bay waters exporting from the mangroves following a flood tide and peak concentrations were associated with export due to rainfall. The amount of net export from each basin forest was similar, although the concentration of organic carbon in each were different. Monthly net organic carbon export was proportional to the cumulative tidal amplitude within the forest. Total organic carbon export was 64 gC m^?2 yr^?1 and DOC was 75% of the total. A comparison of organic carbon export among riverine, fringe and basin mangroves suggests that tidal hydrology influences the proportion of litter fall that is exported from mangroves; and the magnitude of this organic carbon export from mangroves is related to the cumulative tidal amplitude within the forests.  相似文献   

广西河池地区矿产资源勘查成果展销会情况介绍     

项开文 《南方国土资源》1996,(3)

１９９５年７月１１日—１２日，广西地矿厅和河池地区行署首次联合举办矿产资源勘查成果展销会，会址设在河池市，与会代表１３０余人。展销会提交大会展销的矿产资源勘查成果３８项，引资勘查项目３８项。经买卖双方三天的洽谈，涉及到的项目２５项，会议期间签订矿产资源勘查成果合同协议４项，愈千万元，取得较好的社会经济效益。为地勘资金多渠道来源开辟了新路子，对促进地勘单位地质找矿工作及勘查成果有偿使用发挥了重要作用  相似文献   

Spectroscopic binaries near the North Galactic Pole paper 18: HD 118670     

R. F. Griffin 《Journal of Astrophysics and Astronomy》1990,11(4):533-540

Photoelectric radial-velocity measurements show that HD 118670 is a double-lined spectroscopic binary in an orbit which is not quite circular and whose period is about 48 days. Spectral types of K0 V and K7 V would satisfy the photometry and the mass ratio; the mass function would then suggest the possibility of eclipses. However, actual spectral classification indicates a luminosity somewhat above the main sequence  相似文献