• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.42.4-43
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• 2020

The hydrogen-rich envelope mass of a dying massive star is the key factor that determines the type and properties of the resulting supernova. Emulating wind-driven mass loss of single stars with the MESA(Modules for Experiments in Stellar Astrophysics) stellar evolution code, we made a grid of models for a large parameter space of initial mass (12 M⊙ to 30M⊙), metallicity (solar, LMC and SMC), hydrogen envelope mass (0.01M⊙ to 10M⊙) for progenitor stars in their final step of evolution. Our results suggest the final luminosity of the progenitor is largely determined by the initial mass, which means there is luminosity degeneracy for stars with the same initial mass but with different hydrogen-rich envelope masses. Since we can break this degeneracy by correcting luminosity with surface gravity (spectroscopic HR diagram), we can infer the exact mass property of an observed progenitor. The surface temperature drastically varies near the envelope mass of ~0.1M⊙ and surface temperature of ~10000 K, where the demarcation between the hydrogen-rich envelope and the helium core lies, which explains the rarity of 'white' supergiants. There also exists a discontinuity in the chemical composition of the progenitor envelope around this critical hydrogen-rich envelope mass of ~0.1 M⊙, which can be tested in future observations of "flash spectroscopy" of supernovae.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.191-196
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• 2004

This study proposed the analysis of mass position detection and modified stiffness due to the change of the mass and stiffness of structure by using the original and modified dynamic characteristics. The method is applied to examples of a cantilever and 3 degree of freedom by modifying the mass. The predicted detection of mass positions and magnitudes are in good agrement with these from the structural reanalysis using the modified mass.

• Korean Journal of Veterinary Research
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• v.22 no.1
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• pp.81-84
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• 1982

Renal dysfunction was experimentally induced with reductions in renal mass in dogs and then the remaining kidney function was estimated by blood urea nitrogen and serum creatinine concentrations. During experimental period, blood urea nitrogen and serum creatinine concentrations showed no variance in dogs with 50% reductions in renal mass, but these values were remarkably increased in dogs with 75% reductions in renal mass. It was considered that 75% reductions in renal mass was applicable as experimental models for renal dysfunction.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.181-186
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• 1998

A modelling method for the vibration analysis of rotating cantilever plates with a concentrated mass is presented. The equations of motion for the rotating plates with a concentrated mass located in an arbitrary position are derived. For the modelling of the concentrated mass, a mass density Dirac delta function is used. The effects of concentrated mass and its location, angular speed, and hub radius of the rotating plate on the natural frequencies are studied. Particularly, mode shape variations due to some parameter variations are investigated.

• Mass Spectrometry Letters
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• v.9 no.3
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• pp.73-76
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• 2018

The number of matched peaks (NMP) is estimated as the spectral similarity measure in tandem mass spectral library searches of small molecules. In the high resolution mode, NMP provides the same reliable identification as in the case of a common dot-product function. Corresponding true positive rates are ($94{\pm}3$) % and ($96{\pm}3$) %, respectively.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1992.04a
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• pp.26-29
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• 1992

Modern tall buildings are subject to wind induced oscillations. Those oscillations can cause discomfort to the occupants. To control these motions, tuned mass dampers have been used. In this paper, component node synthesis, based on Lagrange multipliers formulation. is applied to the along-wind motion of tall buildings with multiple tuned mass dampers. Spectral densities of accelerations of top floor are compared by changing the numbers and locations of tuned mass dampers. It is found that multiple tuned mass dampers can be more effective than single tuned mass damper in reducing the acceleration response.

• Bulletin of the Korean Chemical Society
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• v.35 no.3
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• pp.955-957
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• 2014

• Journal of Chest Surgery
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• v.26 no.7
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• pp.548-551
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• 1993

Calcified right ventricular thrombi are very rare.One case of large clacified thrombus in right ventricle being seen in a 65-year old man, is presented. He had dyspnea and generalized edema.The chest film showed a large calcified mass in cardiac shadow especially in lateral view.On echocardiography and chest computed tomography, large calcified mass density occupied nearly entire right ventricular outflow tract.The mass removal was performed through right ventriculotomny.The mass was whitish, stony hard, measured 4 cm x 4.5 cm x 8 cm, tightly attached to right ventricular infundibular septum and ventriculoinfundibular fold.

• Bulletin of the Korean Chemical Society
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• v.30 no.8
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• pp.1864-1866
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• 2009

• Journal of The Korean Astronomical Society
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• v.38 no.3
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• pp.357-363
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• 2005

A deep stellar analysis is introduced for the poorly studied open cluster NGC 2509. The Near-IR database of the digital Two Micron All Sky Survey (2MASS) has been used to re-estimate and refine the fundamental parameters of the cluster, i.e. age, reddening, distance, and diameter. As well as, luminosity function, mass function, total mass, relaxation time, and mass segregation of NGC 2509 have been estimated here for the first time..