The rotational structure of the B-X system of sulfur dimers in the spectra of Comet Hyakutake (C/1996 B2)     

Sang J. Kim  M.F. A'Hearn  R. Meier 《Icarus》2003,166(1):157-166

We have constructed line-by-line fluorescence models for the ro-vibrational bands of the B-X system of sulfur dimers (S₂). For the first time the detailed rotational lines of the bands are clearly resolved in the high-resolution echelle spectra of Comet Hyakutake (C/1996 B2), which were obtained at the Kitt Peak 4-m telescope on 26.4 March 1996 (UT). In order to construct satisfactory band models of the B-X system, we first compared the models to laboratory spectra available in literature, and then compared the models including Swings effects to the high-resolution spectra of Hyakutake. From the model fits, we derived a rotational temperature of 70±10 K, which should represent a temperature of a coma region close to the nucleus, where most of the S₂ emissions originate. We present previously proposed scenarios for the origin of S₂ in cometary comae, and compare them with our spectral analysis.  相似文献   

Acoustic tomography for monitoring the Sea of Japan: a pilot experiment     

Spindel  R.C. Jungyul Na Dahl  P.H. Suntaek Oh Eggen  C. Young Gyu Kim Akulichev  V.A. Morgunov  Y.N. 《Oceanic Engineering, IEEE Journal of》2003,28(2):297-302

A pilot experiment was conducted in the Sea of Japan (also called the East Sea) in September-October 1999, to assess the possibility of using acoustic tomographic techniques for monitoring water mass structure and dynamics. Acoustic m-sequence signals at various frequencies between 250 and 634 Hz were transmitted from bottom-mounted acoustic sources in shallow water off the coast of Vladivostok to vertical-array receiving systems deployed off the north coast of Ulleung-Do island (S. Korea), 558 km to the south. The data are analyzed for temporal correlation, time spread, and transmission loss and are interpreted in terms of a tomographic system for monitoring the East Sea.  相似文献   

Application of generalized contaminant retardation factor to a multi‐phase system     

Song‐Bae Kim  Dong‐Ju Kim 《水文研究》2003,17(15):3059-3068

In this study, a generalized contaminant retardation factor applicable to a multiphase system where various types of colloids exist simultaneously with contaminants is derived and incorporated into an equilibrium model which is successfully applied to experimental data for which phenanthrene was used as hydrophobic organic contaminants and dissolved organic matter (DOM) or bacteria as mobile carriers. Based on the parameter values for the experimental data regarding the association of phenanthrene with solid matrix, DOM and various bacterial isolates, numerical experiments are performed to examine the transport behaviour of hydrophobic organic contaminants in various types of the multiphase system. Numerical experiments demonstrate that the extent of contaminant transport enhancement depends on the adsorption affinity of the colloid, its concentration and its mobility, and that the importance of a third phase to contaminant transport needs to be evaluated carefully with respect to the relevance of experimental conditions applied to realistic environmental conditions. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

Is the Parker Instability a Viable Mechanism for the Formation of Giant Molecular Clouds?     

Jongsoo Kim  Dongsu Ryu  Seung Soo Hong 《Astrophysics and Space Science》2004,292(1-4):255-260

The stratified interstellar medium has been known to be subject to the Parker instability, and the instability has been considered as a plausible mechanism for the formation of giant molecular clouds (GMCs). By presenting our recent efforts to understand the instability through linear analyses and numerical simulations, we raise a negative point of view that the Parker instability alone could not form GMCs.  相似文献   

Numerical analysis of bacterial transport in saturated porous media     

Song‐Bae Kim 《水文研究》2006,20(5):1177-1186

A mathematical model to describe bacterial transport in saturated porous media is presented. Reversible/irreversible attachment and growth/decay terms were incorporated into the transport model. Additionally, the changes of porosity and permeability due to bacterial deposition and/or growth were accounted for in the model. The predictive model was used to fit the column experimental data from the literature, and the fitting result showed a good match with the data. Based on the parameter values determined from the literature experimental data, numerical experiments were performed to examine bacterial sorption and/or growth during bacterial transport through saturated porous media. In addition, sensitivity analysis was performed to investigate the impact of key model parameters for bacterial transport on the permeability and porosity of porous media. The model results show that the permeability and porosity of porous media could be altered due to bacterial deposition and growth on the solid matrix. However, variation of permeability due to bacterial growth was trivial compared with natural permeability variation. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

Rayleigh scattering cross-section redward of Lyα by atomic hydrogen     

Hee-Won Lee  Hee Il Kim 《Monthly notices of the Royal Astronomical Society》2004,347(3):802-806

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The Y 2 Isochrones     

Sukyoung K. Yi  Pierre demarque  Yong-Cheol Kim 《Astrophysics and Space Science》2004,291(3-4):261-262

We present a new set of isochrones in which the effect of the α-element enhancement is fully incorporated. The isochrone tables, together with interpolation routines in age and chemical composition, and in [α/Fe] are available on request as well as from the electronic version of our ApJ papers. Newly derived ages of Galactic globular clusters using these isochrones are 20 to 30% smaller than previous estimates.  相似文献   

Analysis of Cryptosporidium parvum oocyst transport in porous media     

Song‐Bae Kim  M. Yavuz Corapcioglu 《水文研究》2004,18(11):1999-2009

Cryptosporidium parvum is a protozoan parasite, transmitted through aqueous environments in the form of an oocyst. In this study, a transport model into which sorption, filtration and inactivation mechanisms are incorporated is applied to simulate laboratory column data, and the suitability of a kinetic model to describe the C. parvum oocyst transport and removal in porous media is compared with an equilibrium model. The kinetic model is applied to simulate previous column experimental data and successfully simulates the concentration peak; the late time tailing effect appeared in the breakthrough curves, indicating that the kinetic model is more suitable than the equilibrium one at simulating the fate and transport of the oocysts in porous media. Simulation illustrates that sorption causes retardation along with a tailing in the breakthrough curve. Additionally, filtration acts as a major mechanism of removing the oocysts from the aqueous phase, whereas the role of inactivation in reducing the viable oocyst concentration is minimal. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

INTEROBJECT STRUCTURE OF UNGROUPED IRON METEORITES AS REVEALED BY ADVANCED CLUSTERING: METHODS AND CHEMICAL FEATURES     

Kim H. Esbensen  L. Kaufman  D.L. Massart 《Meteoritics & planetary science》1984,19(2):95-109

Using the MASLOC clustering strategy, 61 ungrouped iron meteorites are probed for physico-chemical clusters. The existing classification of 13 resolved chemical groups is used as an internal coherence reference. Results include tentative establishment of a new group: ID (7 members), with chemical features similar to those of the non-magnetic groups IAB and IIICD. Six additional pairings, all with magmatic chemical signatures, are also recognized.  相似文献   

Monitoring of drawdown pattern during pumping in an unconfined physical aquifer model     

Seoung‐Sup Lee  Joung‐Souk Kim  Dong‐Ju Kim 《水文研究》2001,15(3):479-492

In this study, we attempted to analyse a drawdown pattern around a pumping well in an unconfined sandy gravelly aquifer constructed in a laboratory tank by means of both experimental and numerical modelling of groundwater flow. The physical model consisted of recharge, aquifer and discharge zones. Permeability and specific yield of the aquifer material were determined by Dupuit approximation under steady‐state flow and stepwise gravitational drainage of groundwater, respectively. The drawdown of water table in pumping and neighbouring observation wells was monitored to investigate the effect of no‐flow boundary on the drawdown pattern during pumping for three different boundary conditions: (i) no recharge and no discharge with four no‐flow boundaries (Case 1); (ii) no recharge and reservoir with three no‐flow boundaries (Case 2); (iii) recharge and discharge with two no‐flow boundaries (Case 3). Based on the aquifer parameters, numerical modelling was also performed to compare the simulated drawdown with that observed. Results showed that a large difference existed between the simulated drawdown and that observed in wells for all cases. The reason for the difference could be explained by the formation of a curvilinear type water table between wells rather than a linear one due to a delayed response of water table in the capillary fringe. This phenomenon was also investigated from a mass balance study on the pumping volume. The curvilinear type of water table was further evidenced by measurement of water contents at several positions in the aquifer between wells using time domain reflectometry (TDR). This indicates that the existing groundwater flow model applicable to an unconfined aquifer lacks the capacity to describe a slow response of water table in the aquifer and care should be taken in the interpretation of water table formation in the aquifer during pumping. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献