• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.407-408
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• 2013

Thin transparent conductive oxides (TCOs) having a thickness lower than 30 nm have been widely usedin touch screen panels. However the resistivity of the TCO films significantly increases as the thickness decreases, due to the poor crystallinity at very thin thickness of TCO films. In this study, we have investigated the effect of electron beam irradiation during the sputtering on the electrical properties and transmittance of 30 nm-thick ITO films, which have a different SnO2 atomic percent, prepared by magnetron sputtering at room temperature. Fig. 1 shows the variation of resistivity of ITO films with a different SnO2 atomic percent for both the normal ITO films and electron beam irradiated ITO films. As shows in Fig. 1, the electron beam irradiation to the ITO (SnO2 weight percent 10%) films during the sputtering resulted in a significantly decreased in resistivity from $7.4{\times}10^{-4}{\Omega}-cm$ to $1.5{\times}10^{-4}{\Omega}-cm$ and it also increased in transmittance from 84% to 88% at a wavelength of 550 nm. These results can be attributed to energy transfer from electron to ad-atoms of ITO films during the electron beam irradiated sputtering, which can enhance the crystallinity of 30 nm-thick ITO films. It is strongly indicate that electron beam irradiation can greatly improve the electrical properties and transmittance of very thin ITO films for touch screen panels, flexible displays and solar cells.

• Nutrition Research and Practice
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• 제1권4호
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• pp.279-284
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• 2007

Solar ultraviolet (UV) irradiation leads to distinct changes in the skin connective tissues by degradation of collagen, which is a major structural component in the extracellular matrix. UV irradiation induces the production of matrix metalloproteinases (MMP) capable of attacking native fibrillar collagen and responsible for inhibiting the construction of collagenous extracellular matrix. In this study, we attempted to investigate the protective actions of Rubus coreanus ethanol extract (RCE) on the MMP production and the consequent procollagen/collagen degradation in UV-B-irradiated human dermal fibroblasts. The analytical data showed that Rubus coreanus ethanol extract was mostly comprised of cyanidin 3-rutinoside. Pre-treatment of fibroblasts with this extract inhibited UV-B-induced production of MMP-1, MMP-8 and MMP-13 in dose-dependent manners. In addition, Western blot analysis and immunocytochemical staining assay revealed that RCE markedly augmented the cellular levels of procollagen/collagen declined in UV-B-exposed dermal fibroblasts. These results demonstrate that RCE blocks UV-B-induced increase of the collagen degradation by inhibiting MMP production. Thus, RCE may act as an agent inhibiting excessive dermal collagen degradation leading to the skin photoaging.

• 천문학논총
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• 제12권1호
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• pp.47-62
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• 1997

In this paper we present a newly improved telescope control software and a newly developed data analysis software package for effective use of the Solar Flare Telescope(SOFT) The telescope control software permits us to make not only auto tacking of the SOFT, but also quantitative measurement of the solar irradiation, allowing us to provide weather monitorings. In addition we introduce an IDL widget software package for both monochromatioc (MONO version) and polarimetric data (VMG version) analysis. The MONO version is capable of loading FITS files, changing colors and contrast, image processing, displaying plots, and saving displayed plots by selected formats The VMG version, on the other hand provides a calibration of polarimetric data and plots of reduced vector magnetic fields.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2005년도 춘계학술대회
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• pp.127-131
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• 2005

The paper addresses modeling and analysis of a grid-connected photovoltaic generation system (PV system). PSCAD/EMIDC. an industry standard simulation tool for studying the transient behavior of electric power system and apparatus. is used to conduct all aspects of model implementation and to carry out extensive simulation study. An equivalent circuit model of a solar cell has been used for modeling solar array. A PWM voltage source inverter (VSI) and its current control scheme have been implemented. A maximum power point tracking (MPPT) technique is employed for drawing the maximum available energy from the PV array. Comprehensive simulation results are presented to examine PV array behaviors and PV system control performance in response to irradiation changes. In addition, dynamic responses of PV array and system to network fault conditions are simulated and analysed

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.495-498
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• 2008

Photocatalytic water splitting into $H_2$ and $O_2$ using semiconductors has received much attention, especially for its potential application to direct production of $H_2$ for clean energy from water utilizing solar light energy. Since the report of Fujishima and Honda on the water splitting by photoelectrochemical cells, numerous different semiconducting materials have been used as photocatalysts for hydrogen generation from water. Among them, platinized titania significantly accelerates hydrogen production from water. For geometrical improvement of $TiO_2$ particle, porous $TiO_2$ structure was proposed and studied such as nanofiber, nanorod and nototubes. This research focuses on finding out the optimum temperature and electrolyte to produce $H_2$ by solar water splitting.

• 한국물환경학회지
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• 제26권4호
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• pp.707-712
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• 2010

Nitrogen-doped $TiO_2$ particles have been successfully prepared using titanium tetraisopropoxide as the Ti source and urea as the nitrogen source. As-prepared nitrogen-doped $TiO_2$ was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller method (BET) and ultraviolet-visible light (UV-vis) absorption spectra techniques. Photocatalytic degradation of Methylene Blue (MB) has been carried out in both solar light (UV-vis) and the visible region (${\lambda}=420nm$). Nitrogen-doped $TiO_2$ exhibits higher activity than the commercial $TiO_2$ photocalyst, particularly under visible-light irradiation because bandgap of nitrogen-doped $TiO_2$ becomes remarkably decreased.

• 신재생에너지
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• 제2권2호
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• pp.9-15
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• 2006

The application of photovoltaics into building as integrated building components has been paid more attention worldwide. Photovoltaics or solar electric modules are solid state devices, directly converting solar radiation into electricity; the process does not require fuel and any moving parts, and produce no pollutants. And the prefab building method is very effective because the pre- manufactured building components is simply assembled to making up buildings in the construction fields especially the sandwich panel. So, the purpose of this research is to integrated prefab building materials depending on the cooling type of PV modules. It is concluded that the prediction of BIPV system's performance should be based on the more accurate PV module temperature. From the basis of these results on the correlation of temperature and irradiation were obtained.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.273-273
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• 2006

The encapsulation of volatile organic electrolytes is a major challenge in practical applications of the DSSC. Ionic liquid (IL) within polymer electrolytes is an attractive candidate for replacement. Here we used a low viscosity ionic liquid 1-ethyl 3-methylimidazolium thiocyanate in order to modify ionic conductivity (${\sigma}$) of polymer electrolyte ($PEO:Kl/l_{2}$) and hence DSSC efficiency. The doping of IL enhanced ${\sigma}$ and attained maximum (${\sigma}=7.62{\times}10^{-4}S/cm$) at 80 wt% of IL concentration. Beyond this it was harder to get stable films. XRD confirmed that the intensity of the sharp PEO crystalline peaks decreased when IL was added. The DSC studies confirmed the reduction in crystallinity by adding ionic liquid.The efficiency of solar cell using aforesaid material was 0.6 % at 1 sun irradiation.

• 태양에너지
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• 제18권1호
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• pp.27-34
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• 1998

태양광 발전 시스템의 운용에 있어서 부하의 변동, 일사량, 주변온도등에 의한 최대전력점의 추종은 매우 어려운 기술을 요구한다. 본 연구에서는 이러한 최대전력점의 추종에 있어 빠른 수렴 특성을 얻기 위한 알고리즘으로써 신경 제어기법을 이용하여서 기존의 제어 방식에 의한 동특성과 비교하여 적절한 제어기법 및 시스템동작의 우수한 특성을 얻게 되었다. 즉 최대전력점의 추종 및 안정한 전원의 공급을 갖게되었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.360-361
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• 2008

A new kind of SBM co-polymer binder as styrene, n-butyl acrylate, and methacrylic acid (SBM) monodisperse co-polymer binder materials basted on $TiO_2$ pastes was synthesized and this $TiO_2$ pastes were applied of dye-sensitized solar cells (DSSCs). The SBM co-polymer binder was prepared by soap-free emulsion copolymerization using a PEG-EEM macromonomer. The photoanodes were characterized by morphology investigated from field emission scanning electron microscopy (FE-SEM). The photoelectrochemical properties of the thin films and the performance of DSSCs were measured by photovoltaic-current density. DSSC based on the emulsion co-polymer binder was obtained conversion efficiency of 7.1% under irradiation of AM 1.5($100mWcm^{-2}$).