• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.3
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• pp.384-393
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• 2002

The effects of hole expansion angle and the arrangement of nozzles on a film cooling system for a turbine-blade-shaped surface were experimentally investigated. Liquid crystal with flue-temperature correlation and an image processing system were employed to evaluate surface temperature. Distributions of cooling effectiveness were then presented to figure out the change of heat transfer characteristics with different geometric conditions of cooling-holes. It was found thats the averaged cooling efficiency on the suction surface was maximum with 10 degree of the cooling hole expansion angle. It was also shown that the averaged cooling efficiency on the pressure surface and the averaged cooling efficiency for dual array case were not affected by the hole expansion angle.

• 대한예방의학회:학술대회논문집
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• 1996.10a
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• pp.213-214
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• 1996

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.2
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• pp.296-301
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• 2010

The purpose of this study was to investigate the mechanism of Hexane extract of Fructus Ligustri Lucidi (HFLL)-induced regulation of melanogenesis. An apparent down-regulatory effect of tyrosinase activity was observed when B16F10 cells were incubated with HFLL. Interestingly, HFLL did not inhibit the catalytic activity of cell-free tyrosinase from B16F10 cells, whereas kojic acid directly inhibited tyrosinase activity. Regarding protein levels of melanogenic enzymes, the amounts of tyrosinase and tyrosinase-related protein 1 (TRP-1) were decreased by HFLL, while the amount of tyrosinase-related protein 2 (TRP-2) slightly was reduced after incubation with HFLL. Treatment with HFLL was found to down-regulate microphthalmia-associated transcription factor (MITF). These results suggest that HFLL is an effective inhibitor of pigmentation caused by down regulation via MITF, tyrosinase, and TRP-1 expressions.

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.2
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• pp.236-241
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• 2010

The purpose of this study was to investigate the mechanism of ethanol extract of Agrimonia pilosa Ledeb. (EAP)-reduced melanogenesis and diphenyl-picryl-hydrazyl (DPPH) radical scavenging activity. Agrimonia pilosa Ledeb., a perennial herbaceous plant, has been used as an antihemorrhagic, anthelminntic, and antiinflammatory agents in Chinese herbal medicine. In the present study, we observed that melanin synthesis and tyrosinase activity of B16F10 cells were significantly decreased by EAP. However, EAP could not suppress tyrosinase activity in the cell-free system, whereas kojic acid directly inhibited tyrosinase activity. Furthermore, EAP decreased the protein expression of tyrosinase, tyrosinase-related prootein 1 (TRP-1), and tyrosinase-related prootein 2 (TRP-2). EAP scavenged DPPH radical up to 41% with 100 ${\mu}g/m{\ell}$ concentration. These results suggest that the hypopigmentary effect of EPA was due to regulation of tyrosinase protein.

• Transactions of the KSME C: Technology and Education
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• v.5 no.1
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• pp.69-77
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• 2017

Nanotechnology, along with Information Technology (IT) and Bio-technology (BT), has been regarded as a core area that will drive technological revolution of $21^{st}$ century. South Korea and other countries with advanced scientific and technological research programs are investing heavily in the field, and among its various aspects, nanomaterial industry is considered to be at the heart of this global competition. In this review, we look at nanomaterials industry from the perspective of mechanical engineering. Nanomaterials exhibit unique characteristics differing from those of micron, or sub-micron sized materials, and hence are potentially able to open up new opportunities. Specifically, environmental and biological sciences, energy, and catalysis are areas that are expected to benefit from these developments.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.58.1-58.1
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• 2011

CIS(CuInSe2)계 화합물 태양전지는 높은 광흡수계수와 열적 안정성으로 고효율 태양전지 제조가 가능하여 태양전지용 광흡수층으로 매우 이상적이다. 미국 NREL에서는 이러한 CIGS 태양전지를 Co-evaporation 방법으로 제조 20%이상의 에너지 변환 효율을 달성하였다고 보고하였다. CIGS 태양전지의 경우 기존의 유리 기판 대신 유연한 철강 기판을 사용해 태양 전지를 flexible하게 제조 할 수 있다는 장점이 있다. 이러한 flexible 태양전지의 경우 기존의 rigid 태양전지의 적용분야 뿐만 아니라 BIPV, 선박, 장난감, 군용, 자동차등 더욱 더 많은 분야에 활용이 가능하다. 본 연구에서는 기존의 rigid한 기판인 soda lime glass와 flexible 기판인 stainless steel 기판으로 소자를 제조하여 효율을 비교 분석 및 stainless steel 기판의 표면 처리 방법에 따라서 표면 조도의 특성을 분석하여 stainless steel 기판별 효율 특성도 비교 분석 하였다. 후면전극으로는 약 $1{\mu}m$의 Mo를 DC Sputtering 방법을 이용하여 증착하였고, CIGS 광흡수층은 약 $2.5{\mu}m$의 두께로 미국의 NREL과 같은 3 stage 방식을 이용하여 광흡수층을 Co-Evaporation 방법으로 제조하였고, 버퍼층인CdS는 약 50nm의 두께로 CBD 방법으로 제조 하였으며, 창층인 ZnO는 약 500nm 두께로 RF Sputtering 방법으로 제조 하였고, 마지막으로 약 $1{\mu}m$ 두께의 Al 전면전극은 Thermal Evaporation 방법으로 제조 하였다. 소자의 물리적, 전기적 특성을 분석하기위해 FE-SEM, AFM, Solar Cell Simulator 분석을 실시하였다.

• Applied Chemistry for Engineering
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• v.25 no.6
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• pp.586-591
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• 2014

In this study, the diarylide compound pigment of high hiding power and vivid color was synthesized successfully by controlling several factors such as pH, coupler solution temperature, kind and addition amount of dispersion precursor, and crystallization temperature in the process of coupling synthesis. The properties of samples were measured by the means of FT-IR, UV-Vis spectroscopy, PSA, zeta potential, and turbiscan. It was found that the highly dispersive sample could be prepared by introducing the dispersive precursor.

• Applied Chemistry for Engineering
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• v.25 no.4
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• pp.357-362
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• 2014

To prepare diketopyrrolopyrrole (DPP) red 254 pigment with high shield and bright color, DPP red 254 crude previously synthesized was treated at various thermal-treat temperature, addition derivative and ball-milling. The properties of samples were measured by the means of FT-IR, UV-Vis spectroscopy, TEM, PSA, BET surface area analyzer, viscometer and spectrophotometer. It was found that solvent thermal-treatment of the sample prepared after ball-milling as nano-scale was very effective method in pigmentation process.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2495-2496
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• 2002

Most of existing disinfection sterilizer had used mist method that burn chemicals and dust with them by putting chemicals in the course of explosion using gasoline. But, that method is not used because of environmental pollution, and spray method using a high-pressure pump is used in an advanced country. These method is very effective than existing mist method because the effect of chemicals can be appeared as it is when spray chemicals. This research will develop completely automatic multi-function disinfection sterilizer in the first at home that can be liberally used by oneself in order to alternate existing products need addition manpower and can be easily used at a place where sources of electricity is not by using gasoline engine to solve inconvenience by the use of electricity, and can be literally operated above and below, right and left in a driver's seat when is loaded in vehicles.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.249-251
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• 2001

This paper presents performance analysis on a low pass filter of a CT saturation detecting algorithm using difference. At the instants of beginning/end of saturation, the shapes of the secondary current are changed significantly though secondary currents are continuous. At the instants, the second-order or third-order difference of the secondary current has big values because of discontinuity of the first order difference. Thus, the third difference of the current is used to detect the beginning/end of CT saturation. An antialiasing low pass filter removes high frequency components and causes phase lag. A CT saturation detecting algorithm using difference of CT secondary currents is affected by the low pass filter. The algorithm is tested with cutoff frequencies of the filter for the two sampling rates of 64[S/C] and 32 [S/C]. The results of various test cases indicate satisfactory performance of the algorithm.