• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.451-454
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• 1989

A DC thermal plasma generation system for both LPPS and APPS was designed and its characteristics was analysed. Discharge experiments for 60 conical and cylindrical type anode nozzle were conducted and the results were compaerd each other. The flow dependence and the electrode gap dependence were precisely explained and especially voltage jump phenomena under the existance of the parallel magnetic field was studid.

• Journal of the Korean Ceramic Society
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• v.29 no.3
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• pp.183-188
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• 1992

The physical properties of 0.5PZT-0.5(PNN-PZN) ceramics have been investigated as a function of PZN content. A pyrochlore phase exists in the range of 600∼850$^{\circ}C$ and a stable perovskite phase appears above 850$^{\circ}C$. The piezoelectric properties (except electro-mechanical coupling factor) of 0.5PZT-0.5(PNN-PZN) ceramics showed almost linear relationships of PZN content within the range of 0.5PZT-0.5PNN system and 0.5PZT-0.5PZN system. The temperature dependence of piezoelectric constant, the electric field dependence of induced strain and a bend strength are improved by addition of PZN.

• Journal of the Optical Society of Korea
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• v.6 no.1
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• pp.1-4
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• 2002

We studied experimentally the angular spectrum of the light emitted from dye Molecules near a plane boundary. It is confirmed that the molecules near the boundary can emit light into the evanescent wave mode, and the light emission with the angle greater than the critical angle is detected with good accuracy. The angular spectrum of the spontaneous radiation is measured, and the spectrum shows contributions from the molecules both near and far away from the boundary. The polarization dependence and the pumping angle dependence are also measured. The experimental results are in good agreement with quantum theory.

• Radiation Oncology Journal
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• v.6 no.1
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• pp.109-116
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• 1988

The Alcyon Co-60 gamma rays was studied for electron contamination. The surface dose, attributable almost entirely to contamination electrons, has a linear dependence on field width for square fields and an inverse square dependence on distance from the bottom of the fixed head assembly Build-up and surface dose measurements were taken with and without an acrylic blocking tray in place. Further measurements were made with a copper filter designed to reduce secondary electrons emitted by photon interactions with the acrylic tray. The results are discussed in relation to skin sparing effect for radiation therapy Patients. And to achieve the maximum skin sparing effect, the selection of the optimum SSD and TSD is needed.

• Progress in Superconductivity
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• v.13 no.1
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• pp.47-51
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• 2011

Mono-atomic-layer graphene is an interesting system for studying the relativistic carrier transport arising from a linear energy-momentum dispersion relation. An easy control of the carrier density in graphene by applying an external gate field makes the system even more useful. In this study, we measured the Josephson current in a device consisting of mono-layer graphene sheet sandwiched between two closely spaced (~300 nm) aluminum superconducting electrodes. Gate dependence of the supercurrent in graphene Josephson junction follows the gate dependence of the normal-state conductance. The gate-tunable and relatively large supercurrent in a graphene Josephson junction would facilitate our understanding on the weak-link behavior in a superconducting-normal metal-superconducting (SNS) type Josephson junction.

• Journal of Magnetics
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• v.2 no.4
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• pp.135-137
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• 1997

We report the salient features of the magnetic properties of amorphous TM70Cr5Si10B15(TM=Fe, Co, Ni) alloys. The temperature dependence of magnetization for amorphous ribbons were measured by a SQUID and a VSM from 5 K to 700 K under an external field of 10 kOe. Except TM70Cr5Si10B15 that shows a paramagnetic behaviour, both Fe and Co based amorphous alloys show a typical ferromagnetic thermo-magnetization curves. For these two ferromagnetic alloys, the saturation magnetization in the temperature range from 5 K to about 0.4 Tc can be descrived by the Bloch relation, Ms (T)=Ms(0) [1-BT3/2-CT5/2]. The spin wave stiffness constants and the range of exchange interaction were analyzed from the magnetization behaviour. The variation of the magnetic properties are discussed and compared with the composition of the alloys.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1445-1447
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• 1994

This paper deals with the edge effect in thin insulating films, focusing on their dependence on film thickness, so we derived a simple mathematical form which depicts that reducing film thickness lowers the field at the electrode edge. we expect that this result may be suitable to problems with multi level insulating films.

• Bulletin of the Korean Chemical Society
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• v.30 no.5
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• pp.1143-1146
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• 2009

[$Mn_{12}O_{12}(azo-L)_{16}(H_2O)_4$] (1), a new Mn12 single molecule magnet containing a photochromic azobenzene ligand, has been successfully synthesized by substitution of acetate ligand of Mn12 with 6-[4-{4-hexyloxyphenyl( azo)}-phenoxy]hexanoic-1-acid. The reversible photoisomerization of the azobenzene group was confirmed by UV-visible absorption spectroscopy. The temperature and field dependence of dc susceptibility and the temperature and the frequency dependence of ac susceptibility were measured for the cis and the trans isomer of 1. The magnetization value of the cis isomer in dc measurement is higher than that of the trans isomer. The cis isomer of 1 has a slower relaxation because cis-trans photoisomerization of the azobenzene group in peripheral ligands induces changes in its structure and dipole moment.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.313-316
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• 2003

The lead zirconate titanate, $Pb(Zr_{0:52}Ti_{0:48})O_3$, films of $0.5\;{\mu}m,\;1\;{\mu}m$ and $2\;{\mu}m$ thickness were fabricated on $Pt/Ti/SiO_2/Si$ substrate by the rf magnetron sputtering method. The PZT films were annealed using by a rapid thermal annealing (RTA) method. The thickness dependence of the film structure, dielectric properties, Polarization-electric field hysteresis loops and capacitance-voltage characteristics were investigated over the thickness range of $0.5\;{\mu}m,\;1\;{\mu}m$ and $2\;{\mu}m$. According to the XRD patterns of the films, (110) peak intensity increases with film thickness increased. The increase of PZT films thickness leads to the decrease of the remanent polarization and the dielectric constant.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.758-761
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• 1995

The magnetization of $Mn_{1-x}Co_{x}Pt_{3}$ ordered alloys was measured at various temperatures and the pressure effect on $T_{c}$ for X=0.25, 0.5 and 0.6 was examined. The X dependence of $T_{c}$ determined by Arott plot has a minimum near X=0.6. The field-cooling effect measurement for X=0.5 shows a reentrant spin glass behavior. It is found that there is a concentration showing no pressure dependence of $T_{c}$ between X=0.25 and 0.5. These magnetic properties are discussed with a rigid band model.