• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2018년도 춘계학술대회 논문집
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• pp.68-68
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• 2018

Nanoporous or nanotubular metal oxide can be fabricated by anodization of metal substrate in fluoride contained electrolytes. The approach allows various transition metals such as Zr, Hf, Nb, Ta to form highly ordered oxide nanostructures. These oxide nanostructures have various advantages such as high surface area, fast electron transport rate and slow recombination in semiconductive materials. Recently, vanadium oxide nanostructures have been drawn attentions due to their superior electronic, catalytic and ion insertion properties. However, anodization of vanadium metal to form oxide layers is relatively difficult due to ease formation of highly soluble complex in water contained electrolyte during anodization. Yang et al. reported $[TiF_6]^{2-}$ or $[BF_4]^-$ in electrolyte helps to formation of stable oxide layer [1, 2]. However, the reported approaches are very sensitive in other parameters. In this presentation, we deal with the other important key parameters to form ordered anodic vanadium oxide such as pH, temperatures and applied potential.

• 한국표면공학회지
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• 제30권4호
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• pp.231-238
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• 1997

Tantalum oxide thin filme has an amorphous structure and a high resistivity. Its stoichiometric structure was $Ta_2O_{5.3}$ and the transmission ratio was 80%. The high resistivity of $Ta_2O_{5.3}$ thin film electrolyte made an EC windows without electrical shottness, but the bleached/colored cur rent was very low because of the low ion conductivith. Upon adding moisture into the system, the $\Delta$T increased upto 25 %. proton concentration increase was the main cases to improve optical property. The influence of adding precious or transition metal film(~100 $\AA$ thickness) in $Ta_2O_5$layer on the color change performance was observed. The metal insertion layers had formed hydroxide and they behaved as a stable proton source. The transmission diffrnece and cycle life were greatly enhanced in the case of Ti inssertion.The $\Delta$T was 50% and the cycle life was 18, 000.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.169-170
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• 2006

A band pass filter for the V-band application with unique circuit and structure was designed and implemented using 2-metals, 3-BCB layers. In the mean while the effective electrical conductivity of metal layer was extracted and its value was $4{\times}10^7S/m$. The insertion loss of band pass filter at 60 GHz was 3.0 dB and group delay was below 0.1 ns.

• Journal of electromagnetic engineering and science
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• 제1권1호
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• pp.100-104
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• 2001

Since the most of malfunctions in the industrial equipment controlled by processors is consist of the electrical fast transient (EFT)$^{[1],[2]}$TEX>, the International Electrotechnical Commission (IEC) prepared the dummy signal to test the immunity level of the equipments. To work out a countermeasure for the malfunction, We designed a new electromagnetic compatibility (EMC) filter for high power supply, which is consisted of a feed-through capacitor and ferrite materials with high permeability. The ferrite material is surrounded with a power cable or is inserted on the cable’s second layer in order to increase common-mode inductance. We have obtained a excellent insertion loss characteristics over the frequency band from 150 kHz to 30 MHz. The developed new EMC filter satisfy IEC 61000-4-4 and is suitable for industrial, militaly, and medical equipments with reduced malfuntions.

• Applied Science and Convergence Technology
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• 제23권5호
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• pp.289-295
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• 2014

${\alpha}-V_2O_5$ nanorods were grown by means of electron beam irradiation and thermal oxidation methods and the visible emission properties of the nanorods grown by both methods were investigated. The growth and crystallinity of the nanorods were greatly enhanced by the insertion of a buffer layer. The emission spectra of the nanorods grown by thermal oxidation and electron beam irradiation showed a peak centered at 710~720 nm, which is believed to be due to oxygen vacancies introduced during the growth process. Also, the emission peak centered at 530 nm observed in the $V_2O_5$ nanorods grown by electron beam irradiation was considered to be due to the band edge transition as a result of the enhanced crystallinity.

• 한국광학회:학술대회논문집
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• 한국광학회 2000년도 하계학술발표회
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• pp.34-35
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• 2000

A Y-branch phase modulator made of an electro-optic(EO) polymer has been designed and fabricated. An EO polymer, PMMA-DR1, is used for the core layer, and UV-curable polymers, UV-15 and UV-15 LV, for the cladding layers. The rib type polymeric waveguides are fabricated by the reactive ion etching method and their EO effects are obtained by the poling process. The optical properties of the fabricated phase modulator are as follows: the halfwave voltage, $V_{\pi}$, is 25 V, the insertion loss of TM mode is 13.8 dB, and the intensity modulation is 0.17 % (V).

• Journal of Chest Surgery
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• 제25권5호
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• pp.550-554
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• 1992

The selection of an appropriate surgical technique for repair of aneurysm of the ascending aortia with aortic insufficiency is unsettled. The etiology of the disease process has been the best indicator for the type of repair. Placement of a supracoronary graft[seperate graft and valve] is a compromise if the coronary ostia are displaced cephalad by the aneurysm, where as insertion of a valved conduit is difficult and unnecessary if the coronary ostia are normally placed. A 53 year old female patient underwent primary repaiar of proximal dissected layer and aortic valve replacement with 24mm carbomedics, The operative findings consisted of a supravalvular intimal tear, cicumferential dissection, dilated aortic annulus and normal position of coronary ostia. She is good physical activity now llmonths posoperatively.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2016년도 자성 및 자성재료 국제학술대회
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• pp.73-74
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• 2016

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 C
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• pp.1034-1038
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• 1995

The purpose of this study is to research and develop $TiS_2$ composite cathode for lithium polymer battery(LPB). $TiS_2$ electrode represent a class of insertion positive electrode used in Li secondary batteries. In this study, we investigated preparation of $TiS_2$ composite cathode and AC impedance response of $TiS_2$ composite/SPE/Li cells as a function of state of charge(SOC) and cycling. The resistance of B type cell using $TiS_2PEO_8LiClO_4PC_5EC_5$ composite cathode was lower than that of A type cell using $TiS_2PEO$ composite cathode. The cell resistance of B type cell is high for the first few percent discharge, decreases for midium discharge and then increases again toward the end of discharge. We believe the magnitude of the cell resistance is dominated by passivation layer impedance and small cathode resistance. AC impedance results indicate that the cell internal resistance increase with cycling, and this is attributed to change of passivation layer impedance with cycling. The passivation layer resistance($R_f$) of B type cell decreases for the 2nd cycling and then increases again with cycling. Redox coulombic efficiency of B type cell was about 141% at 1st cycle and 100% at 12th cycle. Also, $TiS_2$ specific capacity was 115 mAh/g at 12 cycle.

• 한국재료학회지
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• 제24권3호
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• pp.152-158
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• 2014

We report the effect of the fabric of the surface microstructure on the CO gas sensing properties of $SnO_2$ thin films deposited on self-assembled Au nanodots ($SnO_2$/Au) that were formed on $SiO_2/Si$ substrates. We characterized structural and morphological properties, comparing them to those of $SnO_2$ thin films deposited directly onto $SiO_2/Si$ substrates. We observed a significant enhancement of CO gas sensing properties in the $SnO_2$/Au gas sensors, specifically exhibiting a high maximum response at $200^{\circ}C$ and quite a low detection limit of 1 ppm level in dry air. In particular, the response of the $SnO_2/Au$ gas sensor was found to reach the maximum value of 32.5 at $200^{\circ}C$, which is roughly 27 times higher than the response (~1.2) of the $SnO_2$ gas sensor obtained at the same operating temperature of $200^{\circ}C$. Furthermore, the $SnO_2/Au$ gas sensors displayed very fast response and recovery behaviors. The observed enhancement in the CO gas sensing properties of the $SnO_2/Au$ sensors is mainly ascribed to the formation of a nanostructured morphology in the active $SnO_2$ layer having a high specific surface-reaction area by the insertion of a nanodot form of Au nucleation layer.