• Geophysics and Geophysical Exploration
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• v.15 no.1
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• pp.8-15
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• 2012

To estimate the S-wave velocity structure beneath the KS31 broad-band station in Wonju, Korea, we used $H-{\kappa}$ stacking and joint inversion of receiver functions and surface-wave dispersion curves derived from 297 teleseismic events (Mw > 5.5) recorded during the period between 2002 and 2009. We thereby determined that the average depth to a nearly flat Moho is $32.4{\pm}0.5\;km$ within tens of kilometer radius of the seismic station. For the crust at this location, we estimate an average shear-wave velocity of 3.69 km/s and a ratio of P- to S-wave velocities, $V_p/V_s$, of $1.72{\pm}0.04$, as is typical for continental crust. A negative phase in the receiver functions at 1 s indicates the presence of a shearwave low velocity layer in a depth interval of 10 to 18 km in the upper crust beneath the KS31 station.

• Journal of the Korean Chemical Society
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• v.44 no.1
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• pp.17-23
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• 2000

Electrodes of the polycationic film with electropolymerized $[Ru(v-bpy)_3]^{2+}$ having about 1:1 ratio of $PF6^-/ClO_4^-$as the doped counter ions, were modified with xylenol orange and diethylditbiocarbamate by ion exchange which had stability constant as 38.6 and 17.5 respectively. These electrodes were employed in the quantitative multiple determination of U(W) in solution. The working electrode of electrochemical cell for the analytical signal was Pt/p-$[Ru(v-bpy)_3]^{2+}$, ligand, U(VI) with Ag/AgCl reference elecrode. In the stripping voltammetry. electrode process was electron transfer controlled one and calibration curves at the ranges of $1.0{\times}10^{-3}{\sim}1.0{\times}10^{-7}$ M had excellent relationship as 0.99 and relative standard deviation as 5${\sim}$8%.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.1
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• pp.22-29
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• 2000

This paper deals with the dielectric characteristics of $SF_6$ gas gap stressed by $\pm$1.2/44[$mutextrm{s}$] non-oscillating impulse and $\pm$0.4[$mutextrm{s}$]/1.14[MHz] oscillating impulse voltages in the presence of a needle-shape metallic particle in gas-insulated switchgear(GIS). Breakdown voltage-time (V-t) and breakdown voltage-gas pressure (V-p) characteristics were investigated and discussed. The experiments were carried out under highly inhomogeneous field geometry with a needle protrusion whose length and radius are 10[mm] and 0.5[mm], respectively. The gas pressure ranges from 0.1 to 0.5[㎫]. As a result, it was found that the electrical breakdown for both the positive and negative polarity develops with steplike pulses in leader mechanism, When subjected to the positive oscillating impulse voltage, the minimum breakdown voltages appeared in all the gas pressure ranges and the V-t curves have a pronounced upturning at short times to breakdown and give a little dependence of the gas pressure. On the other hand, in the case of the negative polarity the dependence of the V-t and V-p characteristics on the wave shape of the applied voltages is known to be appreciable.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1456-1458
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• 1996

In resonant tunneling diodes with the quantum well structure showing the negative differential resistance (NDR), it is essential to increase both the peak-to-valley current ratio (PVCR) and the peak current density ($J_p$) for the accurate switching operation and the high output of the device. In this work, a resonant interband tunneling diode (RITD) with single quantum well structure, which is composed of $In_{0.53}Ga_{0.47}As/ln_{0.52}Al_{0.48}As$ heterojunction on the InP substrate, is suggested to improve the PVCR and $J_p$ through the narrowed tunnel barriers. As the result, the measured I-V curves showed the PVCR over 60.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.7
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• pp.1042-1048
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• 1990

The approximations of charge relationships at normally doped semiconductor interfaces were qualitatively derived basis on electrical neutrality conditions. Effects of ion adsorptions, activation processes, interfacial structures, rectifying phenomena, and effects of surface potential barriers at the p- and n-Si/CsNO3 aqueous electrolytes, and the p-Si/(1HF:3HNO3:6H2O) electrolyte solutions were investigated using a cyclic voltammetric method. The space charge acts the most important role for the pn junction structures, the rectifying phenomena, and the activation processes. The Current-Voltage (I-V) characteristics curves significantly depend on developing of the Helmholtz double layers and charging of the show surface states during the activation processes. A linear Current-Voltage characteristics region was observed at the p-Si/(1HF:3HNO3: 6H2O) electrolyte solution interface.

• Biomolecules & Therapeutics
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• v.5 no.4
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• pp.419-425
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• 1997

The pharmacokinetics of DWP20364 (1-cyclopropyl -5-amino-6,8-difluoro-7-(2,7-diazabiclo [3,3,0] oct-4-ene-7-yl)-1,4-dihydro-4-oxoquinoline-3-carboxylic acid), a novel fluoroquinolone containing C7-bicyc-talc structure, were compared with those of ciprofloxacin (CPFX) after single intravenous (i.v.) and oral (p.o.) administration to rats using microbiological assay (bioassay). After i.v. administration to rats, the plasma concentrations of the two drugs declined biexponentially. The terminal half-lives (t$_{1}$2$\beta$/) of DWP20364 were 110$\pm$ 13.2 min and 117$\pm$3.09 min after i.v. and p.o. administration, respectively, and they were significantly higher than those of CPFX (45.5$\pm$9.52 min and 48.3$\pm$ 12.1 min, respectively). Similar results were also obtained from plasma concentrations and area under the plasma concentration-time curves. The total body clearance of DWP20364, 7.82$\pm$0.37 ml/min/kg was significantly slower than that of CPFX, 27.3 $\pm$ 11.1 m1/ min/kg. Above data suggested that the antimicrobial activity of DWP20364 could be longer than that of CPFX. The urinary recovery after i.v. and p.o. administration of DWP20364 was significantly lower than those of CPFX suggesting that the effect of DWP20364 on urinary tract infection could be lower than that of CPFX. The serum protein binding values of DWP20364 at 2$\mu$g/ml were apparently 91.5~93.1% in rats and human. DWP20364 was distributed by the order of liver, lung, kidney, sf)leon, heart, muscle and brain collected at 30 min after orally administered.

• Journal of the Korean Vacuum Society
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• v.10 no.2
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• pp.257-261
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• 2001

InAs/GaAs quantum dots between InGaAs/GaAs superlattices were grown by MBE. The quantum dots size is shown to be very uniform by measuring photoluminescence spectra of quantum dots. Single photon structures based on self-consistent calculation were grown and single photon devices were fabricated by e-beam lithography. The electrical hystereses of I-V curves for single Photon devices would result from single electron-hole recombination, where the resonant-tunneling voltages of electron and hole are different.

• Proceedings of the KIEE Conference
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• 2004.11b
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• pp.158-161
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• 2004

This paper presents practical applications of reactive power and voltage planning to obtain voltage stability and operational voltage level for 2005 year summer peak Korea power system. It also describes the new electric facilities, operation criteria, voltage levels, MVAr flows, reactive power reserves in each control area. And reactive compensation devices are installed to maintain established voltage levels and stability margins. This simulation results show the improvement of voltage levels and the increase of reactive margins & interface flow margins. Finally, the paper reports the necessity of dynamic reactive reserves. It can be applied to analysis reactive compensation requirements and P-V & V-Q curves by PSS/E & VSAT.

• Journal of the Korean Institute of Telematics and Electronics
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• v.5 no.1
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• pp.1-5
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• 1968

GaAs single crystals were grown epitaxially from Ga solution with carrier concentrations in the range and electron mobilities between 7,500 and 9,300$\textrm{cm}^2$/v-sec. at 300$^{\circ}$K, and 50,000 and 95,000 $\textrm{cm}^2$/V-sec. at 77$^{\circ}$K. A comparison of the theoretical and experimental curves for the mobility vs. temperature indicates that the significant scattering mechanisms are ionized impurities and phonons in the temperature range of 77$^{\circ}$K to 439$^{\circ}$K. This indicates that the epitaxial layers do not contain other mobility limiting imperfections to a significant degree. Photoluminescence spectra of the. epitaxial layers did not show any emission due to deep lying imperfection leve1s.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.263-266
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• 2001

In this paper, we investigated dielectric properies for BST thin films that was deposited on MgO/Si substrates using RF magnetron sputtering. In here, MgO film was used to perform that a diffusion b arrier between the BST film and Si substrate and a buffer layer to assist the BST film growth. A d eposition condition for MgO films was RF Power of 50W, substrate temperature of room temperature and the working gas ratio of Ar:O$_2$ were varied from 90:10 to 60:47. Finally we manufactured the cap acitor of Al/BST/MgO/Si/Al structure to know electrical properties of this capacitor through I-V, C-V measurement. In the results, C-V aha racteristic curves was shown a ferroelectric property so we measured P-E. A remanent poliazation and coerceive electric field was present 2$\mu$C/cm$^2$ and -27kV/cm respectively at Ar:O$_2$=90:10. And a va clue of dielectric constant was 86 at Ar:02=90:10.