• Journal of Biosystems Engineering
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• v.35 no.1
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• pp.31-36
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• 2010

A small unmanned helicopter was suggested to replace the conventional spray system. Aerial application using an agricultural helicopter helps precise and timely spraying, and reduces labor intensity and environmental pollution. In this research, a rotor system (SW05) was developed and its lift capability was evaluated. Lift force for the dead weight of the helicopter was obtained at the grip pitch angle of $12^{\circ}$. As the pitch angle increased to $14^{\circ}$ and $16^{\circ}$, the payload increased to 176 N and 216 N, respectively. Compared with SW04 airfoil performance in the total lift, the SW05 airfoil showed nearly the same capacity, but the payload of the SW05 was reduced because of the increased dead weight. A rated flight condition was defined as lifting mean payload of 294 N with the grip pitch angles of $16{\sim}17^{\circ}$ at the rotor rotating speed of 850~950 rpm for the adjusted engine power. The fuel consumption would be 4.8~6.0 L/hr, and the air temperature of cooling fan should be kept below $160^{\circ}C$.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2008.11a
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• pp.538-544
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• 2008

Activated protein C (APC) is thought to exert antiinflammatory activities through the endothelial protein C receptor (EPCR)-dependent cleavage of protease activated receptor 1 (PAR-1) in endothelial cells. Since thrombin cleaves PAR-1 with $\sim$3-4-orders of magnitude higher efficiency, and PAR-1 is a target for proinflammatory activities of thrombin, it is not understood how APC can elicit protective responses through the cleavage of PAR-1. In this study, we demonstrate that EPCR is associated with caveolin-1 in endothelial lipid rafts, but its occupancy by protein C leads to its dissociation from caveolin-1 and subsequent recruitment of PAR-1 to protective signaling pathways through the coupling of PAR-1 to Gi-protein. When EPCR is bound by protein C, the PAR-1-dependent protective response in endothelial cells can be mediated by either thrombin or APC. These results provide a new paradigm for understanding the mechanism through which PAR-1 and EPCR participate in cellular signaling events in endothelial cells.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.486-488
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• 2008

300 MHz가 넘는 초고자장 MRI에서는 송신 또는 수신 RF Magnetic Field 의 불균일도가 심해져서 이를 개선하기 위한 많은 방법들이 제안되고 있다. 그 중 가장 대표적인 방법은 $4{\sim}32$ 채널의 Transmit Array의 각 채널에 인가되는 전압과 위상을 변화시켜 RF Magnetic Field의 불균일도를 개선하는 방법이다. 본 논문에서는 Transmit Array 내부에서 머리위치의 변화에 따라 RF Magnetic Field ($B_1$ Field) 의 불균일도가 많이 변화하며 이에 따라 RF 송신용 전압과 위상의 Pattern을 새로 최적화 해야 함을 확인하였다. 또한 RF field Mapping을 하기 위해서 Composite RF Sequence를 사용한 Rapid Sequence의 사용과 채널 전압과 위상을 최적화하기 위해서 일반적인 Iterative 방식보다 간편하고 빠른 Target Method를 제안하였다. Driving 패턴의 최적화는 Complex 행렬식을 사용했으며 RF Magnetic Field ($B_1$ Field) 분포는 FDTD 방식으로 계산하였다.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.278-278
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• 2013

최근 나노 입자의 안전성에 대한 연구가 활발하게 이루어 지고 있다. 대부분의 연구는 세포독성과 쥐에 흡입시켜 각 장기에 침착 정도를 측정하는 연구에 집중되어 있고, 나노입자의 리간드 특성에 대한 연구는 활발이 진행되고 있지 않다. 따라서 같은 나노입자를 이용한 연구결과가 다르게 나타나는 것을 종종 확인 할 수 있어서, 나노입자 특성평가의 중요성이 커지고 있다 [1,2]. 본 연구에서는 용매에 리간드가 존재하는 PEG-conjugated AuNPs과 원심분리로 용액내의 free-ligands가 제거된 PEG-conjugated AuNPs에 대하여 ToF-SIMS 이미지를 얻었고, PEG와 AuNPs 이미지의 statistical correlation으로부터 AuNPs의 표면에 존재하는 리간드들의 stability를 평가할 수 있는 방법을 개발하였다. 또한, citrated-conjugated AuNPs을 PEG 리간드로 표면을 치완시키고, phagolysosomal simulant Fulid(PSF) 용액에 incubation 과정 동안의 PEG 리간드가 표면에서 제거되어 용액에 존재함을 확인하였다. ToF-SIMS의 이미지와 statistical correlation을 이용하면 나노입자의 표면에 존재하는 다양한 리간드들의 안정성을 평가할 수 있고, 이를 통한 나노입자의 안전성에 대한 연구에 기여 할 수 있을 것으로 기대된다.

• Journal of Biosystems Engineering
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• v.33 no.3
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• pp.210-215
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• 2008

The objective of this study was to develop models to predict SCC (somatic cell count) in unhomogenized milk by visible and near-infrared (NIR) spectroscopic technique. Total of 100 milk samples were collected from dairy farms and preserved to minimize propagation of bacteria cells during transportation. Reductive reagents such as methyl red, methylene blue, bromcresol purple, phenol red and resazurin were added to milk samples, and then colors of milk were changed based on SCC of milk. For optimal reductive reagents, reaction time was controlled at 3 level of reaction time. A spectrophotometer was used to measure reflectance spectra from milk samples. The partial least square (PLS) models were developed to predict SCC of unhomogenized milk. The PLS results showed that milk samples with reductive reagents had a good correlation between predicted and measured SCC at 5 minutes of reaction time in the visible range. The PLS models with resazurin reagent had the best performance in $400{\sim}600\;nm$. The prediction results of milk samples with resazurin had 0.86 of correlation coefficient and 14,184 cell/mL of SEP.

• Bulletin of the Korean Chemical Society
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• v.29 no.10
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• pp.1920-1926
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• 2008

We investigated the C-H bond activation mechanism of aldimine by the [RhCl$(PPH_3)_3$] model catalyst using DFT B3LYP//SBKJC/6-31G*/6-31G on GAMESS. Due to their potential utility in organic synthesis, C-H bond activation is one of the most active research fields in organic and organometallic chemistry. C-H bond activation by a transition metal catalyst can be classified into two types of mechanisms: direct C-H bond cleavage by the metal catalyst or a multi-step mechanism via a tetrahedral transition state. There are three structural isomers of [RhCl$(PH_3)_2$] coordinated aldimine that differ in the position of chloride with respect to the molecular plane. By comparing activation energies of the overall reaction pathways that the three isomeric structures follow in each mechanism, we found that the C-H bond activation of aldimine by the [RhCl$(PH_3)_3$] catalyst occurs through the tetrahedral intermediate.

• Proceedings of the KIEE Conference
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• 2005.11a
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• pp.36-38
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• 2005

This study is about how to lower the driving voltage that enables to move the micro droplet by the EWOD (Electro Wetting On Dielectric) mechanism. EWOD is well known that it is used ${\mu}-TAS$ digital micro fluidics system. As the device which is fabricated with dielectric layer between electrode and micro droplet is applied voltage, the hydrophobic surface is changed into the hydrophilic surface by electrical property. Therefore, EWOD induces the movement of micro droplet with reducing contact angle of micro droplet. The driving voltage was depended on the dielectric constant of dielectric layer, thus it can be reduced by increase of dielectric constant. Typically, very high voltage ($100V{\sim}$) is used to move the micro droplet. In previous study, we used $Ta_{2}O_{5}$ as the dielectric layer and driving voltage was 23V that reduced 24 percent compared with $SiO_2$. In this study, we used $BZN(Bi_{2}O_{3}ZnO-Nb_{2}O_{5})$ layer which had high dielectric constant. It was operated the just 12V. And micro droplet was moved within Is on 15V. It was reduced the voltage until 35 percents compare with $Ta_{2}O_{5}$ and 50 percents compare with $SiO_2$. The movement of micro droplet within 1s was achieved with BZN (ferroelectrics)just on 15V.

• The Research Journal of the Costume Culture
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• v.15 no.4
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• pp.702-712
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• 2007

The purpose of this study was to understand the current trend with regard to the material of jeans and the making method of jeans pattern and the characteristics of washing processing through the overall production status of jeans in casual brands and to offer the basic data for producing the high efficient jeans. The results were as follows. According to the survey of production status of jeans in casual brands, the fabric mixture was highest in the order of non-stretch denim 100% cotton, stretch denim cotton/spandex mix and denim with $1{\sim}2%$ weft direction spandex mix. The most frequently used processing method for denim was in the order of normal finishing, mercerization finishing, soft finishing and pigment finishing. The most frequently used method of washing finishing for jeans was in the order of forming by embossing washing, bio stone washing, normal washing, bio washing, and bio stone bleach washing. The average shrinkage was higher on waist circumference and pants length of warp direction rather than hips circumference, thigh circumference, hem circumference of weft direction.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.3102-3107
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• 2008

This paper was focused on the particulate matter (PM) on the gasoline and bio ethanol. Bio ethanol as a clean fuel is considered one of the alternative fuels that decreased the PM emission from the vehicle. Particle formation in SI engine was depended on the fuel and engine operating condition. In this paper, Particle number concentration behaviors were analyzed by DMS500 (Differential Mobility Spectrometer) and CPC (Condensation Particle Counter) instrument which was recommended by PMP (Particle Measurement Programme). Particle emissions were measured with various engine operating variables such as air excess ratio ($\lambda$), spark timing and intake valve opening (IVO) at part load condition. In vehicle test, the number of particulate matter was analyzed with golden particle measurement system, which was consist of CVS (Constant Volume Sampler), particle number counter and particle number diluter.

• BMB Reports
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• v.56 no.11
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• pp.594-599
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• 2023

A number of therapeutic drugs have been developed from functional chemicals found in plants. Knowledge of plants used for medicinal purposes has historically been transmitted by word of mouth or through literature. The aim of the present study is to provide a systemic platform for the development of lead compounds against breast cancer based on a traditional medical text. To verify our systematic approach, integrating processes consisted of text mining of traditional medical texts, 3-D virtual docking screening, and in vitro and in vivo experimental validations were demonstrated. Our text analysis system identified rutin as a specific phytochemical traditionally used for cancer treatment. 3-D virtual screening predicted that rutin could block EGFR signaling. Thus, we validated significant anti-cancer effects of rutin against breast cancer cells through blockade of EGFR signaling pathway in vitro. We also demonstrated in vivo anti-cancer effects of rutin using the breast cancer recurrence in vivo models. In summary, our innovative approach might be proper for discovering new phytochemical lead compounds designing for blockade of malignant neoplasm including breast cancer.