• 공업화학
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• 제18권4호
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• pp.320-325
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• 2007

본 연구에서는 재래식 및 마이크로파 합성법을 통하여 비수계 유기용매인 diethanolamine을 용매로 하여 초산니켈 수용액과 히드라진 수화물로부터 니켈 분말을 합성하였다. X선 회절분석, 주사 전자현미경 분석, 열분석 및 X선 광전자 분광기 분석등을 통하여 마이크로파의 비열적 효과 및 반응 조건이 니켈분말의 합성에 미치는 영향을 조사하였다. 재래식 합성과 비교해보면, 마이크로파를 이용한 합성에서 마이크로파의 비열적 효과에 기인하여 상대적으로 응집이 적게 일어나고, 입자 크기는 작고, 입도 분포는 균일하였다.

• Journal of Electrical Engineering and Technology
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• 제10권5호
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• pp.2120-2125
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• 2015

In this paper, a rectangular waveguide probe with a ridge-loaded straight slot (RLSS) is presented for a near-field scanning microwave microscope (NSMM). The RLSS is located laterally at the end wall of the cavity and is loaded on double ridges in a narrow straight slot to improve the spatial resolution compared with a straight slot. The probe consists of a rectangular cavity with an RLSS and a feed section of a WR-90 rectangular waveguide. When the proposed NSMM is located at distance of 0.1mm in front of a substrate without patches or strips, the simulated full width at half maximum (FWHM) of the probe improve by approximately 31.5 % compared with that of a straight slot without ridges. One dimensional scanning of the E-plane on a sample under test was conducted, and the reflection coefficient of the near-field scanning probe is presented.

• Advances in nano research
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• 제5권3호
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• pp.203-214
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• 2017

In this study we present the reaction mechanism of $Cu_2ZnSnSe_4$ (CZTSe) nanoparticles synthesized by microwave-assisted chemical synthesis. We performed reactions every 10 minutes in order to identify different phases during quaternary CZTSe formation. The powder samples were analyzed by x-ray diffraction (XRD), Raman spectroscopy, energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The results showed that in the first minutes copper phases are predominant, then copper and tin secondary phases react to form ternary phase. The quaternary phase is formed at 50 minutes while ternary and secondary phases are consumed. At 60 minutes pure quaternary CZTSe phase is present. After 60 minutes the quaternary phase decomposes in the previous ternary and secondary phases, which indicates that 60 minutes is ideal reaction time. The EDS analysis of pure quaternary nanocrystals (CZTSe) showed stoichiometric relations similar to the reported research in the literature, which falls in the range of Cu/(Zn+Sn): 0.8-1.0, Zn/Sn: 1.0-1.20. In conclusion, the evolution pathway of CZTSe synthesized by this novel method is similar to other synthesis methods reported before. Nanoparticles synthesized in this study present desirable properties in order to use them in solar cell and photoelectrochemical cell applications.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.2
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• pp.719-722
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• 2003

Ferroelectric $Pb(Zr_{1-x}Ti_x)O_3$ (PZT) films were deposited on (001) MgO single crystals using sol-gel method. Structural properties and surface morphologies of PZT films were investigated using an X-ray diffractometer and a scanning electron microscopy, respectively. The dielectric properties of PZT films were investigated with the dc bias field using interdigitated capacitors (IDC) which were fabricated on PZT films using a thick metal layer by photolithography and dry etching process. The small signal dielectric properties of PZT films were calculated by a modified conformal mapping method with low and high frequency data, such as capacitance measured by an impedance gain/phase analyzer at 100 kHz and reflection coefficient (S-parameter) measured by a HP 8510C vector network analyzer at 1 -20 GHz. The IDC on PZT films exhibited about 67% of capacitance change with an electric field of 135 kV/cm at 10 GHz. These PZT thin films can be applied to tunable microwave devices such as phase shifters, tunable resonators and tunable filters.

• 한국표면공학회지
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• 제41권2호
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• pp.43-47
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• 2008

Cubic boron nitride(c-BN) films were deposited on tungsten carbide insert tool by microwave plasma enhanced chemical vapor deposition(MPECVD) from a gas mixture of triethyl borate$(B(C_2H_5O)_3)$, ammonia $(NH_3)$, hydrogen$(H_2)$ and argon(Ar). The qualities of deposited thin film were investigated by x-ray diffrac-tion(XRD), field emission scanning electron microscopy(FE-SEM) and micro Raman spectroscope. The surface morphologies of the synthesised BN as well as crystallinity appear to be highly dependent on the flow rate of $B(C_2H_5O)_3$ and $(NH_3)$ gases. The deposited film had more crystallized phases with 5 scem of $B(C_2H_5O)_3$ and $(NH_3)$ gases than with 2 sccm, and the phase was identified as c-BN by micro Raman spectroscope and XRD. The adhesion strength were also increased with increasing flow rates of $B(C_2H_5O)_3$ and $(NH_3)$ gases.

• 청정기술
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• 제16권2호
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• pp.140-144
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• 2010

리튬이온전지의 음극활물질로서 titania-silica 혼합물을 얻기 위해 TiCl4와 TEOS를 전구체로 사용하여 졸-겔법을 이용해 합성하였다. 졸-겔법을 이용하여 혼합물을 합성할 경우에 균일한 분포를 갖는 화합물을 제조할 수 있다. 마이크로파를 이용하여 혼합물을 열처리하여 새로운 물성을 갖는 화합물의 제조를 시도하였다. 합성한 화합물의 물성을 측정하기 위하여 화합물의 조성, 열처리 온도 및 마이크로파 처리등을 실험변수로 사용하였다. 특성 분석방법으로는 합성물질의 구조적 특성과 입자의 표면분석을 하기 위해 XRD(X-ray diffraction)와 SEM (scanning electron microscopy)과 전지 충 방전기를 사용하여 충 방전에 따르는 전지의 용량변화를 관찰하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.142-142
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• 2009

Bismuth-substituted yttrium iron garnet(Bi-YIG; $Bi_xY_{3-x}Fe_5O_{12}$, x=0, 0.5, 1.0, 1.5, 2.0) thin films were fabricated on glass substrates using a metal organic decomposition (MOD) method. The dielectric property was measured by NSMM(Near-field scanning microwave microscopy) system that operating frequency is 4 Ghz. The obtained reflection coefficient $S_{11}$ of the Bi:YIG thin films with different bismuth concentration was increased as the bismuth concentration increased due to the lattice mismatch and vacancy of ions because of a lager ionic radius of bismuth ion than yttrium ion.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 디스플레이 광소자분야
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• pp.132-136
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• 2004

열 증착 방법을 이용하여 copper(II)-phthalocyanine(CuPc) 박막을 glass 기판 위에 제작하였다. 열처리 조건은 $150^{\circ}C$에서 후열(annealing) 처리 하는 방식과 예열하는 두 가지 방식으로 달리하였다. 제작된 박막의 전기전도도를 평가하기 위해 마이크로웨이브 근접장 효과를 이용한 근접장 현미경(near-field scanning microwave microscope)을 이용하여 비파괴적인 방식으로 CuPc 박막의 반사계수(reflection coefficient)를 측정하였다. CuPc 박막의 전기전도도 특성을 UV 흡수도를 통한 에너지 밴드갭의 shift 현상과 관련지어 설명하고 또한 x-ray diffraction(XRD) data를 통해 박막의 결정 특성과 비교하였다. 박막 표면 특성은 SEM(scanning microscope microscopy)을 통해 관측하였다. 열처리 조건에 따른 CuPc 박막의 전기전도도 특성은 후열 처리한 박막의 경우 예열 처리한 박막보다 전기 전도 특성이 향상되었음을 관측할 수 있었다.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2014년도 추계학술대회 논문집
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• pp.260-261
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• 2014

$TiO_2$ nanotubes (TNT) synthesized by microwave-assisted hydrothermal method by using $TiO_2-P25$ as a precursor at hydrothermal temperature $150^{\circ}C$ in 4 hours. The concentration of alkaline solution is between 4M and 10M. Samples were characterized by X-ray diffraction (XRD), Raman spectroscopy (RS), Transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) and UV-vis DRS spectroscopy. The results demonstrated the effects of the alkali concentration to the formation of nanotubes. The photocatalytic activity was investigated by degradation of Methylene Blue (MB).

• Elastomers and Composites
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• 제50권4호
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• pp.274-278
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• 2015

Nanosized gold particles were synthesized by microwave irradiation in a mixture composed of potassium tetrachloroaurate(III) n-hydrate, sodium citrate dihydrate and Tween 20. The synthesized gold particles were characterized by UV-vis spectrophotometer, scanning electron microscopy, and X-ray diffraction techniques. Using UV-vis spectroscopy, it was confirmed that gold nanoparticles act as a catalyst in the reduction of 4-nitroaniline with sodium borohydride to form 1,4-diaminobenzene. Additionally, we studied the kinetics of this reductive reaction in the presence of these gold nanoparticles under various conditions.