• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.395.1-395.1
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• 2014

차세대 디스플레이 소자 기술로 많은 주목을 받고 있는 유기발광소자는 현재 전류효율 향상과 낮은 구동전압과 관련하여 연구가 활발하게 진행되고 있다. 음극과 양극 전극에서 유기물 층으로 전자와 정공의 주입이 많아져도 유기발광 층에서 재결합하는 전자와 정공의 균형이 맞지 않으면 전류 효율과 휘도가 낮아지는 문제점이 있다. 유기발광소자에서 홀 주입 층으로 사용하는 자기조립박막층은 일반적인 유기발광소자에서 정공의 이동도가 낮은 단점을 보완하여 발광층에서 전자와 정공의 균형을 향상하여 전류효율을 향상과 낮은 구동전압 특성을 나타낸다. 본 연구에서는 홀 주입 층으로 사용되는 각각의 자가조립박막을 형성할 물질이 용해되어 있는 에탄올 용액에 ITO를 담가 자가조립박막을 ITO 위에 형성 시킨다. 각각의 홀 주입 층으로 사용된 자가조립박막층의 chain group의 길이와 ITO와 결합하는 head group에 따라 달라지는 쌍극자 모멘트에 의한 홀 주입의 변화를 통해 각 소자의 전류효율과 구동전압 관찰할 수 있었다. 자가조립박막층의 chain group의 길이가 길어질수록 전극으로부터 유기물 층으로의 홀 주입을 방해하여 발광 층에서의 전자와 정공의 재결합 균형이 무너짐으로써 전류효율과 휘도가 낮아지는 경향을 볼 수 있었다. 이 연구 결과는 자가조립박막층을 홀 주입 층으로 대체하는 구조로 유기발광소자의 효율 향상에 대한 기초자료로 활용할 수 있다.

• Journal of the Korean Magnetics Society
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• v.12 no.3
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• pp.103-108
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• 2002

We investigated magnetoresistance(MR) and exchange bias properties by annealing in top and bosom type spin valves (SV) with nano-oxide layers (NOL). In top SVs with NOL, MR ratio of 9.2% is obtained after postdeposition annealing at 250$\^{C}$. In bottom SVs with NOL, MR ratio of 10.1 % is obtained after postdeposition annealing at 250$\^{C}$. Therefore, specular reflection of the NOL in bottom SVs is higher than that of the NOL in top SVs. Exchange biasing of bottom SVs with NOL is 28% higher than that of bottom SVs without NOL after annealing. This enhancement of exchange biasing is thought to be due to the reduced magnetic moment of the pinned layer with NOL and enhanced (111) FeMn texture.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.04b
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• pp.131-136
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• 1993

일반적으로 공작기계 주축계에 대해서 요구되는 기본적인 항목들로는 고강성, 고감쇠, 고회전정밀도, 저발열, 장수명 등이 있다. 최근에는 이러한 기능들과 함께 가공능률과 가공정밀도의 향상을 도모하기 위해서 고속절삭을 실현햐ㄹ 수 있는 공작기계 주축계의 고속화, 즉 고속 주축계에 대한 연구가 활발히 진행되고 있다. 본 연구에서는 고속주축계의 동특성을 체계적으로해석하기 위해서 주축회전수의 영향을 고려한 유한요소모델(finite element model)을 도입하였다. 특히 주축은 세장비가 비교적 자기 때문에 Timoshenko보 이론으로, 베어링은 유한한 폭을 가지고 있기 때문에 반경방향 외에도 모멘트방향의 강성 및 감쇠특성을 가지고 있는 것으로 모델화 하였다. 그리고 고속주축계의 설계조건들을 도출하기 위해서 동특성 해석결과들로 부터 고속주축계의 모드매개변수들인 고유진동수와 감쇠비에 대한 주축 회전수, 베어링의 지지특성, 베어 링의 간격, 주축재료의 내부감쇠율 등의 영향을 고찰하였다.

• Journal of the Korean Chemical Society
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• v.25 no.4
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• pp.263-269
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• 1981

The substituted pyridinium salts of oxochloromolybdates(V) have been prepared characterized by visible and infrared spectra, and magnetic moments. The electrical conductance of aqueous solutions of substituted pyridinium salts have been measured over a range of concentrations. The results indicate that the complex anions are monomeric in the solid. The magnetic moments of the complexes are similar to the spin-only values. Substituted pyridines are present as pyridinium cation in solid state.

• Journal of the Korean Chemical Society
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• v.25 no.3
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• pp.177-182
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• 1981

Benzoylpyridinium and lutidinium salts containing$ [MoO(NCS)_5]^{2-}$ have been synthesized. The complexes have been characterized by spectroscopic, magnetic susceptibility and conductivity studies. Benzoylpyridinium and lutidinium oxopentaisothiocyanatomolybdates(Ⅴ) arise from d-d and charge transfer transitions. The magnetic moments of the complexes are close to the spin-only values. The complex anions are mononuclear containing N-bonded $NCS^-$ ligand.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.8 no.6
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• pp.629-635
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• 1997

The theory of characteristic modes for coaxial waveguide with periodic axial slots is used to derive the weighted eigenvalue equation for calculating the characteristic values and the characteristic currents. Once the characteristic values and the characteristic currents are obtained, the important quantities such as the equivalent magnetic current, radiation patterns, and RCS are determined. Numerical results of the equivalent magnetic currents, radiation patterns, and RCS are compared with those obtained by use of the method of moments. A fairly good correspondence is observed between them.

• Journal of the Korean Magnetics Society
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• v.17 no.1
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• pp.43-46
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• 2007

The samples were synthesized by using a solid state reaction. The X-ray diffraction pattern for $Ti_{0.96}Co_{0.02}Fe_{0.02}O_2$ showed a pure rutile phase with tetragonal structures. Mixtures of the proper proportions of the elements sealed in evacuated quartz ampoule were heated at $870{\sim}930^{\circ}C$ for one day and then slowly cooled down to room temperature at a rate of $10^{\circ}C/h$. In order to obtain single phase material, it was necessary to grind the sample after the first firing and to press the powders into pellets before annealing them for a second time in evacuated and sealed quartz ampoule. Magnetic properties have been investigated using the vibrating sample magnetometer(VSM). Room temperature magnetic hysteresis(M-H) curve showed an obvious ferromagnetic behavior and the magnetic moment per Fe atom under the applied of 0.8T was estimated to be about $1.3{\mu}_B/CoFe$. But the magnetic moment per Fe atom under the applied of 0.8T was estimated to be about $0.02{\mu}_B/CoFe$ without Ti-getter.

• Journal of the Korean Magnetics Society
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• v.8 no.6
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• pp.374-379
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• 1998

$Mn_1-xCr_xPt_3$ alloy films have been prepared by depositing (Mn, Cr)/Pt multilayers using a rf magnetron sputterer followed by heat treatment. Small and wide angle x-ray diffractometry, magnetic hysteresis loops and Kerr rotation angle spectra of the films have been measured and used to investigate structural, magnetic and magneto-optic properties of the films. The films had a crystal structure of ordered AuCu$_3$ type and the strong preferred orientation of a (111)plane parallel to the film surface. The saturation magnetization of the films was decreased with Cr content reaching almost zero near x=0.58 and then increased for further increasement of Cr content up to x=0.77 over that stayed almost constant. This indicated that Cr atoms were antiferromagnetically coupled with Mn atoms. The magnetic easy axis of MnPt$_3$(x=0) film was parallel to the film surface but those of the films with x$\geq$0.58 increased as Cr content increased reaching about 4 kOe at x=1(CrPt$_3$). The dependence of the Kerr rotation angle on the Cr content was similar to that of the saturation magnetization on the Cr content. The films with x=0.77 and x=1 showed the larger Kerr rotation angle at the wavelengths of near infrared compared to the magneto-optic recording medium, TbFeCo, currently being used.

• Journal of the Korean Chemical Society
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• v.40 no.1
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• pp.65-71
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• 1996

The chemical behaviour of the Eu(Ⅲ) complexes with organic ligands(tris[3-(trifluoromethylhydroxymethylene-camphorato)]) and tris[3-heptafluoropropylhydroxymethylene-camphorato)] has been investigated by the UV/vis-spectrophotometric, magnetic, and electrochemcial methods. The two or three energy absorption bands are observed by the spectra of these complexes. The magnitude of crystal field splitting energy, the spin pair energy and strength were obtained from the spectra of the complexes. These complexes are found to be delocalization, low-spin state, and strong bonding strenth of electron configuration. The magnetic dipolemoment are found to be diamagnetic. The redox reaction processes of complexes were investigated by cyclic voltammetry in aprotic solvent. The redox reaction processes of complexes are turned out to be single or double reaction with respect to one electron diffusion current.

• Journal of the Korean Magnetics Society
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• v.20 no.3
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• pp.83-88
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• 2010

We investigated the electronic structure and magnetism of the (3d, 4d)-Pd alloyed c($2{\times}2$) monolayer systems, by use of the FLAPW band method. For comparison, pure 3d- and 4d-transition metal monolayers are also considered. We found that the antiferromagnetic configuration of pure V monolayers is sustained in the V-Pd alloy system, while the Ti-Pd alloy system is changed to antiferromagnetic configuration from the ferromagnetic state in pure Ti monolayer. The 4d TM (Mo, Ru, Rh)-Pd monolayers are found to be stable in ferromagnetic configurations. The magnetic moments of Ru and Rh atoms in Ru-Pd and Rh-Pd systems are almost same with those of pure Ru and Rh monolayers, while the magnetic moment of Mo atom is increased to $2.98\;{\mu}_B$ in Mo-Pd alloyed system from the value of Mo monolayer, $0.02\;{\mu}_B$.