• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2002년도 춘계학술대회 논문집
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• pp.23-28
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• 2002

This paper describes the machining characteristics of the $MoSi_2$ based composites by electric discharge drilling with various tubular electrodes, besides, Hardness characteristics and microstructures of $Nb/MoSi_2$ laminate composites were evaluated from the variation of fabricating conditions such as preparation temperature, applied pressure and pressure holding time. $MoSi_2$ -based composites has been developed in new materials for jet engine of supersonic-speed airplanes and gas turbine for high- temperature generator. Achieving this objective may require new hard materials with high strength and high temperature-resistance. However, With the exception of grinding, traditional machining methods are not applicable to these new materials. Electric discharge machining (EDM) is a thermal process that utilizes a spark discharge to melt a conductive material, the tool electrode being almost non-unloaded, because there is no direct contact between the tool electrode and the workpiece. By combining a nonconducting ceramics with more conducting ceramic it was possible to raise the electrical conductivity. From experimental results, it was found that the lamination from Nb sheet and $MoSi_2$ powder was an excellent strategy to improve hardness characteristics of monolithic $MoSi_2$. However, interfacial reaction products like (Nb, Mo)$SiO_2$ and $Nb_2Si_3$ formed at the interface of $Nb/MoSi_2$ and increased with fabricating temperature. $MoSi_2$ composites which a hole drilling was not possible by the conventional machining process, enhanced the capacity of ED-drilling by adding $NbSi_2$ relative to that of SiC or $ZrO_2$ reinforcements.

• 대한의용생체공학회:의공학회지
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• 제27권6호
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• pp.409-417
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• 2006

Research on neural circuit is a difficult area due to complexity and inaccessibility. Due to recent developments, the research using multi-electrode array of cells or tissues has become an important research area. However, there are some difficulties to decode the submerged meaning from huge and complex neural data. Moreover, it needs a harmonic collaboration between informatics and bioscience. In this paper, we have developed a custom-designed signal processing technique for multi-electrode array measured neural responses induced by electrical stimuli to the hippocampal tissue slices of the rat brain. The raw data from hippocampal slice using the multi-electrode array system were saved in a computer. Then we estimated characteristic points in each channel and calculated the total activity. To estimate the points, we used the Polynomial Fitting Approximation Method. Using the calculated total activity, we could provide the histogram or pseudo-image matrix to help interpretation of results.

• 한국표면공학회지
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• 제49권6호
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• pp.507-512
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• 2016

Expensive silver powder is used to form electrodes in most IT equipment, and recently, many attempts have been made to lower manufacturing costs by developing powders with Ag-Ni or Ag-Cu core-shell structures. This study examined the sintering behavior of Ag-Ni electrode powder with a core-shell structure for silicon solar cell with high energy efficiency. The electrode powder was found to have a surface similar to pure Ag powder, and cross-sectional analysis revealed that Ag was uniformly coated on Ni powder. Each electrode was formed by sintering in the range of $500^{\circ}C$ to $800^{\circ}C$, and the specimen sintered at $600^{\circ}C$ had the lowest sheet resistance of $5.5m{\Omega}/{\Box}$, which is about two times greater than that of pure Ag. The microstructures of electrodes formed at varying sintering temperatures were examined to determine why sheet resistance showed a minimum value at $600^{\circ}C$. The electrode formed at $600^{\circ}C$ had the best Ag connectivity, and thus provided a better path for the flow of electrons.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2000년도 제18회 학술발표회 논문개요집
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• pp.185-185
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• 2000

플라즈마 연구 및 응용에서 플라즈마를 구성하는 이온에 대한 정보를 얻는 것은 중요하다. 특히 플라즈마 진단, 박막 증착, 플라즈마 코팅, 플라즈마 이온주입 등과 같은 플라즈마 프로세싱에서 이온들의 종류 구성비율 및 분포는 매우 중요하다. 질량분석기는 대개 큰 규모로 복잡하고 값비싼 경향이 있다. 플라즈마 교란을 최소화하면서 충분한 질량분해능을 갖고 국소적으로 이온들을 분석할 수 있는 간단하고 작은 규모의 값싼 질량분석기가 필요하다. 본 연구에서는 플라즈마 내에 존재하는 이온을 분석하기 위하여 간단하고 작은 규모의 값싼 프라즈마 이온 질량분석기를 설계, 제작하였다. 이온 질량분석기는 ion extraction part, double focusing sector magnet, ion collector로 구성되어 있다. 플라즈마에 잠기는 ion extraction part의 외부 전극에 Al2O3를 코팅하여 플라즈마 교란을 최소화하였다. 이온들의 공간적 분포를 측정하기 쉽게 하기 위하여 ion extraction part를 이동하여도 질량여과기를 통과한 후에 접속되는 초점의 위치가 Faraday ion collector 에 고정되도록 ion optical system을 설계하였다. Extracting electrode에 의하여 가속된 이온들이 sector magnet에 들어갈 때 평행이 되게 하기 위하여 여러 개의 미세구조를 갖는 Mo grids를 사용하고 immersion lens를 넣어서 이온 광학 시스템을 구성하였다. extraction electrode와 sector magnet 사이에 보조 electrode를 하나 더 넣어서 extracting electrode와 보조 electrode 사이에 immersion lens를 만들었다. 질량여과기로는 permanent magnet sector와 time-varying electrical field를 결합하여 사용하였다. Extracting electrode에 1kV 정도의 전압을 인가하여 이온들을 가속시키고 sector magnet에 톱니파 형태의 전압을 인가하여 mass spectrum을 얻었다. 이온 질량분석기를 플라즈마 장치에 적용하여 질량분해능 등의 특성을 연구하였다. Hot cathode discharge와 inductively coupled RF discharge에서 발생된 질소 플라즈마를 구성하는 이온들의 종류와 그 구성비율을 연구하였다.

• 대한화학회지
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• 제39권1호
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• pp.47-56
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• 1995

세자리 Schiff base의 몰리브네늄(V) 착물로써 $[Mo(Ⅴ)_2O(SOHB)_4],\; [Mo(Ⅴ)_2O_3(SOIP)_2(NCS)_2]$ 및 $ [Mo(Ⅴ)_2O_3(SOTB)_2(H_20)_2]$ (SOHB: Salicylidene-o-imino hydroxybenzene, SOIP; Salicylidene-o-imino pyridine, SOTB; Salicylidene-o-imino thiolbenzene)들을 합성하였다. 이들 착물들의 원소분석과 금속정량, IR, UV-visible spectrum 및 열무게분석(TGA)으로부터 금속과 리간드의 몰비가 1:1 및 1:2 착물임을 확인하였다. 0.1 M tetraethylammonium perchlorate (TEAP) 지지전해질을 포함한 비수용매에서 순환 전압-전류법과 시차펄스 폴라로그래피에 의한 전기화학적 측정으로부터 이들 착물들은 일전자 전이의 확산지배적인 환원과정이 다음과 같이 진행됨을 알았다. Mo(Ⅴ)Mo(Ⅴ)e-→ Mo(Ⅴ)Mo(Ⅳ)e-→Mo(Ⅳ)Mo(Ⅳ)e-→Mo(Ⅳ)Mo(Ⅲ).

• 한국전기전자재료학회논문지
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• 제24권6호
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• pp.468-472
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• 2011

Conductive $SrMoO_3$ thin films were fabricated by RF magnetron sputtering with the powder-type sputtering target, and annealed for crystallization. When RTP (rapid thermal processing) in vacuum was applied, the fabricated thin films showed the mixed phases of $SrMoO_3$ and $SrMoO_4$, but $SrMoO_3$ phase could be promoted by the lowering of the working pressure during deposition. In order to eliminate $O_2$ gas during deposition and annealing, further lowering of the working pressure and furnace annealing in hydrogen atmosphere were tried. With the optimization of the deposition and annealing conditions, the thin film with nearly single-phase of $SrMoO_3$ was obtained, and it showed good electrical conduction properties with a low resistivity of $2.5{\times}10^{-3}{\Omega}{\cdot}cm$ at room temperature.

• 대한화학회지
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• 제38권2호
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• pp.160-168
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• 1994

다섯자리 Schiff base의 molybdenum(Ⅴ)착물로써 [Mo(Ⅴ)O(Sal-DET)(NCS)] 와 [Mo(Ⅴ)O(Sal-DPT)(NCS)]들을 Sabat법에 의해 합성하였다. 이들 착물들의 원소분석, IR-spectrum, UV-Vis spectroscopy 및 Thermogravimetric analysis(T.G.A.)곡선으로부터 리간드 대 금속의 몰비가 1:1착물임을 확인하였다. 0.1M tetraethyl ammonium perchlorate(TEAP)지지전해질을 포함한 비수용매에서 순환 전압-전류법과 시차펄스 폴라그래피에 의한 전기화학적 측정으로부터 이들 착물들은 dimer로 형성된 후, 일전자 전이의 확전자 전이의 확산지배적인 환원과정이 다음과 같이 네단계로 진행됨을 알았다. 2Mo(Ⅴ)$\rightleftarrow^{e-}$ Mo(Ⅴ)Mo(Ⅳ) $\longrightarrow^{e-}$ 2Mo(Ⅳ), Mo(Ⅳ)$\longrightarrow^{e-}$ Mo(Ⅲ) $\longrightarrow^{e-}$ Mo(Ⅱ)

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.826-829
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• 2002

$MoO_3$ thin films were deposited on electrode and heater screen-printed alumina substrates in en atmosphere by RF reactive sputtering. The deposition was performed at $300^{\circ}C$ with 350W of a forward power in an $Ar-O_2$ atmosphere. The working pressure was maintained at $3{\times}10^{-2}$mtorr and all deposited films were annealed at $500^{\circ}C$ for 5hours. The surface morphology of films was observed by using a SEM and crystalline phases were analyzed by XRD. The sensing properties were investigated in term of gas concentration under exposure of reducing gases such as $H_2$, $NH_3$ and CO.

• 한국재료학회지
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• 제16권5호
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• pp.297-301
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• 2006

Si/Mo multilayer anode consisting of active/inactive material was prepared using rf/dc magnetron sputtering. Molybdenum acts as a buffer against the volume change of the Silicon. Multilayer deposited on RT (reversible treatment) copper foil current collector to enhance adhesion between Silicon and copper foil. Deposited Silicon was identified as an amorphous. Amorphous has a relatively open structure than crystal structure, thus prevents the lattice expansion and has many diffusion paths of Li ion. When deposited time of Silicon and Molybdenum is 30 second and 2 second respectably, electrode has more capacity and good cycle stability. A 3000 nm thick multilayer was maintained 99% of the initial capacity (1624 $mAhg^{-1}$) after 100 cycles. As the increase of the multilayer thickness (4500 nm, 6000 nm), Si/Mo mutilayer anodes show aggravation cycle stability.

• Journal of Electrochemical Science and Technology
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• 제3권4호
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• pp.172-177
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• 2012

Mo-doped $LiFePO_4$ was synthesized via co-precipitation method using sucrose as the carbon source. Structure, surface morphology, and the electrochemical properties of the synthesized olivine compounds were investigated using Rietveld refinement of X-ray diffraction data (XRD), scanning electron microscopy (SEM), and electrochemical charge-ischarge tests. Spherical morphology with the particle size of ${\sim}8{\mu}m$ authenticated the enhanced tap density and volumetric energy density of the synthesized materials. Charge-discharge behavior of $LiFePO_4$ and Mo-doped $LiFePO_4$ cells demonstrated a specific capacity of 130 and 145 mAh $g^{-1}$, respectively. Mo-doped $LiFePO_4$ cells exhibited an excellent discharge capacity at 96 mAh $g^{-1}$ at 7 C-rate.