• Proceedings of the Korean Vacuum Society Conference
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• 1994.02a
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• pp.43-43
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• 1994

We studied chemical reactio of Eu metal on the in situ cleaved CdTe(110) surface by pphotoemission sppectroscoppy using synchrotron radiation. The chamber was maintained with base ppressure $\leq$2${\times}$10-10 mb during the expperiment. The expperiment was carried out in pphoton Factory in Jappan. Core level pphotoemission sppectroscoppy was carried out with Al K${\alpha}$ Line. The CdTe simiconductor was determined to be pp-typpe with low dopping concentration from Hall measurement. We found that there are two reacted pphases of Te with Eu (related to divalent Eu and trivalent Eu, resppectively) from least square fitting of Te 4d sppectra, but three is no indication of Cd reaction. Trivalent Eu exists after roughly one monolayer depposition (600 sec. depposition time is considered as one monolayer), which is also observed at Eu 3d core level sppectra. Overlayer Eu is metallized after roughly 2 monolayers depposition, as can be deduced from the fact that metallic edge near Fermi level begins to appear. The intensity of core-level of Te decreases expponentially at the initial stage (near one monolayer) and after one monolayer depposition it decreases more slowly due to Te out-diffusion. We categorized the growth mode of Eu on CdTe as S-K growth mode (cluster formation after one monolayer deppisition) from the relative intensity pplot of Te 4d normalized to the cleaved surface. At cleaved surface band bending is already established due to surface defects. At first 100 sec. depposition time the shift toward lower binding side by 0.6 eV is found at all core level sppectra of all elements in semiconductor. This shift is considered as the re-adjustment of surface Fermi level to the pposition induced by Eu metal (0.2 eV above the valence band maximum).

• Journal of The Korean Astronomical Society
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• v.51 no.2
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• pp.37-48
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• 2018

Massive stars blow powerful stellar winds throughout their evolutionary stages from the main sequence to Wolf-Rayet phases. The amount of mechanical energy deposited in the interstellar medium by the wind from a massive star can be comparable to the explosion energy of a core-collapse supernova that detonates at the end of its life. In this study, we estimate the kinetic energy deposition by massive stars in our Galaxy by considering the integrated Galactic initial mass function and modeling the stellar wind luminosity. The mass loss rate and terminal velocity of stellar winds during the main sequence, red supergiant, and Wolf-Rayet stages are estimated by adopting theoretical calculations and observational data published in the literature. We find that the total stellar wind luminosity due to all massive stars in the Galaxy is about ${\mathcal{L}}_w{\approx}1.1{\times}10^{41}erg\;s^{-1}$, which is about 1/4 of the power of supernova explosions, ${\mathcal{L}}_{SN}{\approx}4.8{\times}10^{41}erg\;s^{-1}$. If we assume that ~ 1 - 10 % of the wind luminosity could be converted to Galactic cosmic rays (GCRs) through collisonless shocks such as termination shocks in stellar bubbles and superbubbles, colliding-wind shocks in binaries, and bow-shocks of massive runaway stars, stellar winds might be expected to make a significant contribution to GCR production, though lower than that of supernova remnants.

• Korean Security Journal
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• no.8
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• pp.107-125
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• 2004

China is an ancient country that has one of the oldest civilizations on earth. Since the end of 1970s, China has made her administrative and economic reform and opening up to the outside world. Now the administrative and economic reforms has scored great success with a series of important accomplishments. China's peculiar political economy largely explained the changing reform initiatives over times. The problems confronting Chinese officials are markedly different from the West despite the fact the China and the West have engaged their efforts in undertaking administrative reforms in the last two decades or so. The purpose of this study is to analyze the bureaucracy, especially the police civil service system in China. Core features of the institution of China's civil servant system is discussed in this study.

• Geophysics and Geophysical Exploration
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• v.15 no.2
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• pp.102-115
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• 2012

The purpose of this paper is to review several different methods calculating gas hydrate saturations. There are three methods using downhole log data, core data (including pressure core), and seismic velocity data. Archie's equation using electrical resistivity of downhole log data is widely used for saturation calculation. In this case, Archie's parameters should be defined accurately. And the occurrence types of gas hydrate significantly affect to saturation calculation. Thus saturation calculation should be carefully conducted. The methods using chlorinity and pressure core data are directly calculated from core sample. So far, the saturation calculated from pressure core gives accurate and quantitative values. But this method is needed much more time and cost. Thus acquisition of the continuous data with sediment depth is realistically hard. The recent several results show that the saturation calculated from resistivity data is the highest values, while the value calculated from pressure core is the lowest. But this trend is not always absolutely. Thus, to estimate accurate gas hydrate saturation, the values calculated from several methods should be compared.

• Economic and Environmental Geology
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• v.41 no.3
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• pp.345-357
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• 2008

Korea has been one of the top ranked countries in the per capita and total consumption of Cu, Zn, Pb, and Ni since economic development based on manufacturing industries. The current instability of mineral demand and supply in Korea is likely to continue or exacerbate in accordance with economic growth in developing countries such as BRICs. Korea needs to increase the self-development portion of strategic mineral resources including Cu, Zn, Pb, and Ni. Our analysis of mineral demand and supply data predicts a long-run instability of supply and demand for main minerals used in the Korean manufacturing industries, and suggests a long range government policy for stable supply of core mineral resources.

• Journal of the Korean earth science society
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• v.31 no.4
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• pp.370-377
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• 2010

In this study, we investigated the kinematical properties of the L1521F-IRS in Taurus region using HCN (J=1-0) molecular line. The high resolution mapping has carried out by $5{\times}5$ point observations covering $3.7'{\times}3.7'$ area using a 12-m telescope of Arizona Radio Observatory in Tucsan, USA. L1521F which harbors the faint infrared L1521F-IRS, displayed a strong central concentration of integrated intensity in HCN without serious molecular depletion. It showed a symmetric kinematical structure with the opposite infall motion in either side of the central cores. It is a direct evidence of bipolar outflows in the core of L1521F.

• Journal of Magnetics
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• v.18 no.1
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• pp.43-49
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• 2013

A pulsed ferrite magnetic field generator (FMFG) was designed for the use in the 1000 m long through-the-earth (TTE) communication system for mining disaster situations. To miniaturize the TTE system, a ferrite core having 10,000 of permeability was used for the FMFG. Attenuation of the magnetic field intensity from the FMFG (200-turn and 0.18 m diameter) was calculated to be 89.95 dB at 1000 m depth soil having 0.1 S/m of conductivity. This attenuation was lower than 151.13 dB attenuation of 1 kHz electromagnetic wave at the same conditions. Therefore, the magnetic-field was found to be desirable as a signal carrier source for TTE communications as compared to the electromagnetic wave. The designed FMFG generates the magnetic field intensity of $1{\times}10^{-10}$ Tesla at 1000 m depth. This magnetic field is detectable by compact magnetic sensors such as flux gate or magnetic tunneling junction sensor. Therefore, the miniature FMFG TTE communication system can replace the conventional electromagnetic wave carrier type TTE system and allow reliable signal transmission between rescuer and trapped miners.

• Journal of the Korean earth science society
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• v.28 no.5
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• pp.545-555
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• 2007

Ocean general circulation model developed by GFDL on the basis of MOM4 of FMS are examined and evaluated in order to elucidate the global ocean status. The model employs a tripolar grid system to resolve the Arctic Ocean without polar filtering. The meridional resolution gradually increases from $1/3^{\circ}$ at the equator to $1^{\circ}$ at $30^{\circ}N(S)$. Other horizontal grids have the constant $1^{\circ}$ and vertical grids with 50 levels. The ocean is also coupled to the GFDL sea ice model. It considers tidal effects along with fresh water and chlorophyll concentration. This model is integrated for a 100 year duration with 96 cpu forced by German OMIP and CORE dataset. Levitus, WOA01 climatology, serial CTD observations, WOCE and Argo data are all used for model validation. General features of the world ocean circulation are well simulated except for the western boundary and coastal region where strong advection or fresh water flux are dominant. However, we can find that information concerning chlorophyll and sea ice, newly applied to MOM4 as surface boundary condition, can be used to reduce a model bias near the equatorial and North Pacific ocean.

• 한국해양학회지
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• v.23 no.3
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• pp.97-109
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• 1988

The wind stress and the wind-stress curl over the East Sea of Korea are computed from the ship-observed wind data by the FRDA. In order to emphasize the role of the wind in determining the upper-layer structure, rather persistent and strong winds are selected based on the wind-rose data. The monthly averaged wind stresses are comparable in size with the average value over the Japan Sea. But the monthly averaged magnitude of the wind-stress curl is very large compared to the one over the Japan Sea. This may be due to the spatial variation of the wind speeds influenced by the local orography. The wind-driven upper-layer thickness over the East Sea suggests that the site of deep upper layer indeed exists regardless of season but the position does not appear to be fixed. The convergence of warm surface water driven by the wind could be referred as the warm core.

• Nuclear Engineering and Technology
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• v.52 no.12
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• pp.2717-2724
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• 2020

Silicon, especially silicon in the form of SiO₂, is a major component of rocks. Final spent fuel storages, which are being designed, are located in suitable rock formations in the Earth's crust. Reduction of the uncertainty of silicon neutron scattering and capture is needed; improved silicon evaluations have been recently produced by the ORNL/IAEA collaboration within the INDEN project. This paper deals with the nuclear data validation of that evaluation performed at the LR-0 reactor by means of critical experiments and measurement of reaction rates. Large amounts of silicon were used both as pure crystalline silicon and SiO₂ sand. The critical moderator level was measured for various core configurations. Reaction rates were determined in the largest core configuration. Simulations of the experimental setup were performed using the MCNP6.2 code. The obtained results show the improvement in silicon cross-sections in the INDEN evaluations compared to existing evaluations in major libraries. The new Thermal Scattering Law for SiO₂ published in ENDF/B-VIII.0 additionally reduces the discrepancy between calculation and experiments. However, an unphysical peak is visible in the neutron spectrum in SiO₂ obtained by calculation with the new Thermal Scattering Law.