• Journal of the Korean Vacuum Society
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• v.3 no.4
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• pp.442-448
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• 1994

용액분무법으로 RuO2 박막을 석영 기판위에 성장시켰다. RuO2 박막의 결정구조는 정방 구조이 며 격자상수 a0=4.508 A, c0=3.092 A 이였다. RuO2 박막은 금속성 전도성을 나타냈다. RuO2박마의 광흡 수도는 후열처리함에 따라 증가하였고 박막의 광흡수도의 최소값은 후열처리 온도에 의존하지 않으며 에너지로 환산하면 ∼2.0eV로 거의 일정하였다. RuO2 박막의 후열처리의 온도와 후열처리 분위기가 기 판위에 성장된 RuO2 박막의 표면형태 grain 크기 grain 경계폭 전기적특성등에 영향을 미쳤다. RuO2 박 막이 실험실내의 공기중에 노출됨으로서 시료의 표면에 S와 C가 물리 흡착되었으며 sputtering 시간이 증가함에 따라 Ar+ 이온 빔의 충겨으로 RuO2가 부분적으로 환원되어 O원자의 피크 대 피크 높이가 감 소하여 O/Ru 의피크 높이의 비가 낮게 관측되었다.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07b
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• pp.241-243
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• 2005

Horn et al.에 의하여 개발된 THRASH 알고리즘은 대표적인 단백질 질량분석 플랫폼으로써, 극초분해능(ultra high resolution) Fourier Transform 질량분석법을 통해 얻어지는 고집적 전기분무 (electrospray ionization ESI) 질량 스펙트럼 데이터를 분석하는데 이용되고 있다. 하지만 이 알고리즘은 속도 면에서 부족하여 실시간 분석에 한계점을 보이고 있다. 이를 보완하기 위해 본 논문에서는 THRASH알고리즘의 속도를 향상시키는 기법을 제안하고 실험 결과를 통하여 새로운 기법이 융합된 알고리즘의 수행 속도가 기존 THRASH알고리즘의 속도를 비약적으로 향상시킬 수 있음을 보인다.

• Journal of the Korean Electrochemical Society
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• v.19 no.2
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• pp.50-56
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• 2016

Spherical lithium manganese oxide spinel, $Li_{1.10}Mn_{1.86}Al_{0.02}Mg_{0.02}O_4$ was prepared by wet-milling, spray-drying, and sintering process. In the spray-drying process, solid content in slurry was varied from 20 to 30 wt%. In the sintering process, the precursors have been sintered under air or $O_2$ atmosphere. While the as-prepared samples exhibit excellent electrochemical properties at room temperature, the discharge voltage profiles at 5.0C are very different one from another. The origin for the difference especially at initial state of discharge is oxygen defect. The sample prepared in air has larger capacity related to the plateau at 3.3 V (vs. $Li/Li^+$) which is caused by the oxygen defects than the one prepared in $O_2$. The difference of discharge voltage profiles especially at the final state of discharge comes from different diffusion rate of $Li^+$ ions. The sample prepared from 30 wt% solid content of slurry shows twice higher diffusion rate than the samples prepared from 20 wt% solid content, which is attributed to better compactness between primary particles for the sample prepared from 30wt % solid content than the one prepared by 20 wt%.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.44.2-44.2
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• 2011

고분자 전해질 연료전지는 다른 연료전지에 비해 작동온도가 낮고 전류밀도 및 출력밀도가 높으며 시동시간이 짧아서 다양한 분야에 응용이 가능할 것으로 기대된다. 그 중 양극판은 가격비와 중량비가 높아 부품 가격 및 중량을 낮출 경우 파급 효과가 높은 것으로 예상된다. 본 연구에서는 일반적으로 사용하고 있는 스테인리스강보다 가격이 저렴한 저탄소강을 모재로 이용하였다. 저탄소강은 자체로 내식성을 가지지 못하므로, 최근에 차세대 신소재로 각광을 받고 있는 그라핀(graphene)을 전기분무(electro spray coating)법으로 코팅하여 저탄소강의 내식성을 향상시키고자 하였다. 그라핀은 에탄올을 용매로 사용하여 분산하였으며, 분산제로 소량의 다이페닐다이에톡시실란(diphenyldiethoxysilane)을 첨가하여 코팅용액을 제작하였다. 코팅공정은 5~15 kV의 전압을 가하여 1시간동안 코팅을 진행하였으며, 그라핀-저탄소강의 미세구조를 주사전자현미경과 광학현미경을 통하여 관찰하였다. 또한 X-선 회절분석법을 이용하여 그라핀의 결정구조를 분석하였다. 한편 스택의 내부와 유사한 산화성 분위기를 모사하기 위해 $80^{\circ}C$의 0.1N $H_2SO_4$+2ppm $F^-$ 용액에서 내식성 실험을 수행하였고 면간접촉저항을 측정하였다. 그라핀이 코팅된 저탄소강 시편은 고분자 전해질 연료전지 양극판의 요구조건을 만족하였으며, 연료전지 양극판으로서의 사용가능성을 확인하였다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.10
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• pp.1317-1321
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• 2018

PVDF as a semicrystal polymer, having a structure with C-F dipole moments, has been widely investigated because of its excellent chemical stability, mechanical strength, and ferroelectricity. In this study, ferroelectic ${\beta}$ type - PVDF layer was prepared by using an electrostatic spray deposition method and the effects of the addition of Ni-nitrate in precursor solution on the properties of PVDF layer were evaluated. Crystallinity and chemical structure of the PVDF layer were analyzed by a X-ray diffraction and Fourier Transform Infrared Spectrophotometer. Surface structure and fractured cross section of the layer were examined by a field emission-scanning electron microscope. LCR meter was used to obtain the dielectric properties of the layer. As the addition of an inorganic metal salt in PVDF sol, ${\beta}$ type - PVDF crystals were appeared in the hydrated metal salts doped-layer since the strong hydrogen bondings $(O-H{\cdots}F-C)_n$ due to high polarity of OH- were formed.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1423_1424
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• 2009

Dye sensitized solar cells(DSC) have been very economical and easy method to convert solar energy to electricity. DSC can reach low costs in future outdoor power applications. However, to commercialize the DSC, there are still many shortages to overcome such as a low efficiency in a large size DSC. In this study, DSCs were fabricated by an electrospray coating method for the $TiO_2$ thin film. They were compared with DSCs prepared by conventional coating methods. We conducted an experiment to obtain the optimized parameters of voltage, flow rate, incident angle and distance in the electrospray method. After we manufactured $TiO_2$ film using that way, we could analyze the characteristics of DSC through SEM, UV curve, EIS.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.7
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• pp.539-545
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• 2001

Undoped and Co$^{2+}$ $\alpha$-Ga$_2$S$_3$ thin films were grown by spray pyrolysis method. It has been found that these thin films have a monoclinic structure and direct optical energy gap and indirect were located to 3.477eV and 3.123 eV at 10K respectively. In the photoluminescence due to a D0A(donor-acceptor) pair recombination were observed at 502 nm and 671 nm for the $\alpha$-Ga$_2$S$_3$ thin film, where is excited by the 325 nm-line of He-Cd laser. These peaks are identified to be corresponding to the electron transition between the energy levels of Co$^{2+}$ ion sited a the T$_{d}$ symmetry point in the $\alpha$-Ga$_2$S$_3$;Co$^{2+}$ thin film. film.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.11
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• pp.2223-2228
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• 2009

Dye sensitized solar cells(DSCs) have been very economical and easy method to convert solar energy to electricity. DSC can reach low costs in future outdoor power applications. However, to commercialize the DSC, there are still many shortages to overcome such a low efficiency in a large size DSC. In this study, DSCs were fabricated by an electrospray coating method for the $TiO_2$ thin film. They were compared with DSCs prepared by conventional coating methods. We conducted an experiment to obtain the optimized parameters of voltage, flow rate, incident angle and distance in the electrospray method. After we fabricated $TiO_2$ film using that way, we investigated the characteristics of DSC through I-V Curve, SEM and EIS. This novel method shows stable performance with an energy conversion efficiency of 3.44 % under 1 sun illumination (AM 1, $P_{in}$ of $100\;mW/cm^2$).

• Korean Chemical Engineering Research
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• v.54 no.6
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• pp.854-862
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• 2016

As the demand for a clean energy to replace fossil fuel being depleted increases, hydrogen energy is considered as a promising candidate for future energy source. Water electrolysis which produces hydrogen has high energy efficiency and stability but still has a large overpotential for oxygen evolution reaction (OER). In this study, $Co_3O_4$ catalysts with different morphology were prepared by spray pyrolysis from solutions which contain Co precursor and various organic additives (urea, sucrose, and citric acid), followed by post heat treatment. For the catalysts synthesized, X-ray diffraction (XRD) measurements were performed to identify their crystal structure. Morphology and surface shape of the catalysts were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Surface area and pore volume were examined by nitrogen adsortpion & desorption tests and X-ray photoelectron spectroscopy (XPS) was conducted to confirm nitrogen doping. Linear sweep voltammetry (LSV) was carried out to investigate OER activity of $Co_3O_4$ catalysts. As a result, bare-$Co_3O_4$ which has high surface area and small particle size determined by spray pyrolysis showed high activity toward OER.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.4 no.3
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• pp.294-305
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• 1994

The influence of deposition parameter on the electrical, optical andsurface morphology of $SnO_2(:F)$ films prepared by ultrasonic spray deposition using DBDA and $SnCl_4.5H_2O$ as a source material was studied. Resistivity was decreased sharply with increasing F/Sn ratio in solution up to 0.6. Depending on the source material, $SnCl_4.5H_2O$ shows lower resistivity than DBDA. When F/Sn ratio in solution was 1, optical transmittance was higher DBDA than $SnCl_4.5H_2O$.