• 한국세라믹학회지
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• 제30권3호
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• pp.236-242
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• 1993

As the fundamental research on preparation of fine single crystalline ferroxaplana by means of glass-crystallization methods using steel twin-roller, the properties of ferroxplana crystallized from glass were studied. Most of the specimens quenched by twin-roller at about 130$0^{\circ}C$ were glass phase, the crystallization of these glasses underwent multi-steps and ferroxplana phase was only stable in the temperature range of 88$0^{\circ}C$ to 95$0^{\circ}C$. Above 95$0^{\circ}C$ ferroxplana begines to be decomposed in glass. Ferroxplana had such magnetic properties as M8=29emu/g, MHC=166Oe, and Curie Temperature, Tc=610$\pm$5K.

• 소성∙가공
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• 제16권5호통권95호
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• pp.386-390
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• 2007

In order to, simultaneously, synthesize and control the size of microstructure of amorphous/crystalline composites, a repeated extrusion process was performed using the gas atomized $Cu_{54}Ni_6Zr_{22}Ti_{18}$ metallic glass powders and the crystalline brasses. The size of microstructure in the resultant composites was varied depending on the pass of extrusion as well as on the area reduction ratio. The microstructure could be estimated using an equation of $r_n=r_{n-1}/R^{1/2}$, where R is reduction ratio and $r_n$ is the resultant radius of the extruded bar after n pass. Theory of microstructural refinement as well as the relationship between the resultant microstructures and mechanical properties was discussed.

• KIEE International Transactions on Electrophysics and Applications
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• 제2C권5호
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• pp.258-261
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• 2002

Electrical forming dependent current-voltage (I-V) and numerically derived differential conductance(dI／dV) characteristics have been presented in the multi-layer nano-crystalline silicon／oxygen (no-Si／O) superlattice. Distinct staircase-like features, indicating the presence of resonant tunnel barriers, are clearly observed in the dc I-V characteristics. Also, all samples showed a continuous change in current and zero conductivity around OV corresponding to the Coulomb blockade in the calculated dI／dV-V curve. Also, Ra-man scattering measurement showed the presence of a nano-crystalline Si structure. This result becomes a step in the right direction for the fabrication of silicon-based optoelectronic and quantum devices as well as for the replacement of silicon-on-insulator (SOI) in high speed and low power silicon MOSFET devices of the future.

• 한국세라믹학회지
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• 제29권10호
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• pp.765-772
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• 1992

As the fundamental research of preparation of fine single crystalline ferroxplana by means of glass-crystallization methods using steel twin-roller the properties of ferroxplana extracted from cyrstallized glass were studied. Most of all the specimens quenched by twin-roller at about 1350$^{\circ}C$ were glass phase, the crystallization of these glass had multi-steps and ferroxplana phase was only stable untill 900$^{\circ}C$, began to be decomposed from about 950$^{\circ}C$ in glass. The morphology of particle could be controlled by the composition and crystallization condition, and Zn2+ was replaced by reduced Fe2+ which is 2∼3% contents of total Fe. Ferroxplana extracted had such magnetic properties as Ms=34 emu/g, mHc=10 Oe and Curie Temperature, Tc=425K.

• 한국광학회지
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• 제25권1호
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• pp.21-28
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• 2014

본 논문에서는 핀홀어레이를 사용한 완전시차 3D 방식의 초다시점 디스플레이를 제안한다. 이는 시점 이미지를 화면에 나타내는 디스플레이 장치, 완전시차의 구현을 위한 핀홀어레이, 시점 영상들을 동공에 동시에 투영시키기 위한 이미징 렌즈로 구성된다. 제안된 방법은 관찰자에게 수평 및 수직 시차가 동시에 제공되는 초다시점 디스플레이 방법이다. 이에 대한 파라미터들의 분석과 시뮬레이션을 통해 수정체 렌즈의 초점 거리만을 조절함에 따라, 망막에 분포하는 빛들의 분포 및 조도 변화를 확인하였으며, 수정체 렌즈가 이미징 렌즈를 통해 생성된 3D 이미지의 깊이면에 초점을 맺을 때에 가장 선명한 영상이 획득됨을 확인하였다.

• 한국전기전자재료학회논문지
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• 제14권1호
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• pp.48-53
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• 2001

The crystal structure of ZnS fabricated by gas-liquid phase reaction was refined by the Rietveld program using X-ray diffraction data. The R-weighted pattern (R$\sub$wp/) of ZnS powder was 10.85%. The fraction of HCP phase was closely related with extra amount of H$_2$S gas. The lattice parameters and crystalline size were changed by the relative ratio of multi-phase. The luminescence property of ZnS:Cu, Al green phosphors prepared by conventional methods was good in the range of 91∼94% and 150∼190${\AA}$, respectively. According to the maximum entropy electron density(MEED) methods, any defects in (001) plane of cubic phase were not found. We suggest that both the Rietveld and maximum entropy density methods may be useful tools for studying luminescence mechanism of other phosphors materials.

• 한국전기전자재료학회논문지
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• 제30권5호
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• pp.301-306
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• 2017

Wire electrical discharge machining (WEDM) process was evaluated to slice Silicon (Si) for various applications. Specifically, various Si workpieces with various resistances, such as single and multi crystalline Si bricks and wafers were used. As conventional slicing processes, such as slurry-on or diamond-on wire slicing, are based on mechanical abrasions between Si and abrasive, there is a limitation to decrease the wafer thickness as well as kerf-loss. Especially, when the wafer thickness is less than $150{\mu}m$, wafer breakage increases dramatically during the slicing process. Single crystalline P-type Si bricks and wafers were successively sliced with considerable slicing speed regardless of its growth direction. Also, typical defects, such as microcracks, craters, microholes, and debris, were introduced when Si was sliced by electrical discharge. Also, it was found that defect type is also dependent on resistance of Si. Consequently, this study confirmed the feasibility of slicing single crystalline Si by WEDM.

• 한국동물학회지
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• 제31권1호
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• pp.62-70
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• 1988

미토콘드리아가 포함하고있는 결정한유물의 미새구조와 면역황금표식법에 의한 분석을 위하여 우심근 세포의 미토콘드리아에서 전자전달체에 관여하는 효소를 분리하였다. 우심근 미토콘드리아에서 분리된 효소는 실험토끼에 주사하여 (복합체I,NADH-conezyme Q reductase; 복합체 III,Ubiquinol-cytochrome-c-oxldoreductase; 복합체 IV, Cytochrome-c-oxidase)들에 대한 면역항체를 얻었다. 이들 면역항체들은 우심근과 정상인의 골격근 미토콘드리아와 미토콘드리아에 결정함유물을 포함하는 mitochondrical myopathy환자의 골격근 미토콘드리아에 반응시켜 황금입자를 표식하고 전자현미경을 이용하여 이들 면역항체반응을 관찰하였다. 미토콘드리아가 포함하는 결정함유물의 미세구조에는 paracrystalline inclusions body와 multilamellar strudure inclusion body그리고 구형결정함유물(globular crystalline inclusions body) 및 윤형구조 (whirl shaped structure)의 크리스테 중심에 있는 구형결정함유물 등의 4종류로관찰되었다. 복합체 I,복합체 Iv의 효소에 대한 항체를 우심근과 정상인 골격근 그리고 mitochondrical myopathy환자의 골격근에 동일한 면역반응을 시켰을때 미토콘드리아 크리스테에 부착하는 황금입자의 표식 정도는 각각의 근조직에서 유사한 반응이 관찰되었다. 복합체 III의 효소에 대한 항체는 우심근과 정상인의 골격근에서는 유사한 반응이 나타났으나 mitochondrical myopathy환자의 골격근에서는 극히 소수의 황금입자가 관찰되었다. 구형결정함유물은 복합체 I,III,IV의 3종류의 효소에 대한 면역반응 결과 황금입자표식은 관찰되지 않았다. 따라서 mitochondrical myopathy환자의 미토콘드리아에는 복합에 III의 효소가 결핍되었으며 구형결정함유물은 전자전달체 효소들인 복합체 I,III,Iv 효소단백질과는 상관없는 물질로 생각된다.

• Bulletin of the Korean Chemical Society
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• 제11권3호
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• pp.245-248
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• 1990

A series of compounds were synthesized that contain varying number of mesogenic units, 4-n-butylazobenzene moiety, attached to the central benzene ring through ester bond. These compounds were subjected to thermal analysis on a differential scanning calorimeter (DSC) and also on a polarizing microscope. It was found from this study that the presence of mesogenic units in a multi-mesogenic compound does not guarantee for the compound to become mesomorphic and that the linear molecular shape is conducive to form a liquid crystalline phase.

• 한국수소및신에너지학회논문집
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• 제22권2호
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• pp.199-205
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• 2011

Stainless steel 304 and 316 plates were deposited with the multi-layered coatings of titanium film (0.1 um) and gold film (1-2 um) by an electron beam evaporation method. The XRD patterns of the stainless steel plates modified with the multi-layered coatings showed the crystalline phases of the external gold film and the stainless steel substrate. Surface microstructural morphologies of the stainless steel bipolar plates modified with multi-layered coatings were observed by AFM and FE-SEM images. The external gold films formed on the stainless steel plates showed micro structure of grains of about 100 nm diameter. The grain size of the external surface of the stainless steel plates increased with the gold film thickness. The electrical resistance and water contact angle of the stainless steel bipolar plates covered with multi-layered coatings were examined with the thickness of the external gold film.