http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
( Daewoo Lee ),( Sung Ho Kook ),( Hyeok Ji ),( Seung Ah Lee ),( Ki Choon Choi ),( Kyung Yeol Lee ),( Jeong Chae Lee ) 생화학분자생물학회(구 한국생화학분자생물학회) 2015 BMB Reports Vol.48 No.11
There are controversial findings regarding the roles of nuclear factor (erythroid-derived 2)-like 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway on bone metabolism under oxidative stress. We investigated how Nrf2/HO-1 pathway affects osteoblast differentiation of MC3T3-E1 cells in response to hydrogen peroxide (H2O2), N-acetyl cysteine (NAC), or both. Exposing the cells to H2O2 decreased the alkaline phosphatase activity, calcium accumulation, and expression of osteoblast markers, such as osteocalcin and runt-related transcription factor-2. In contrast, H2O2 treatment increased the expression of Nrf2 and HO-1 in the cells. Treatment with hemin, a chemical HO-1 inducer, mimicked the inhibitory effect of H2O2 on osteoblast differentiation by increasing the HO-1 expression and decreasing the osteogenic marker genes. Pretreatment with NAC restored all changes induced by H2O2 to near normal levels in the cells. Collectively, our findings suggest that H2O2-mediated activation of Nrf2/HO-1 pathway negatively regulates the osteoblast differentiation, which is inhibited by NAC. [BMB Reports 2015; 48(11): 636-641]
Optimization Analysis of Trajectory for Re-Entry Vehicle Using Global Orthogonal Polynomial
Daewoo Lee 대한기계학회 2006 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.20 No.10
We present a procedure for the application of global orthogonal polynomial into an atmospheric re-entry maneuvering problem. This trajectory optimization is imbedded in a family of canonically parameterized optimal control problem. The optimal control problem is transcribed to nonlinear programming via global orthogonal polynomial and is solved a sparse nonlinear optimization algorithm. We analyze the optimal trajectories with respect to the performance of re-entry maneuver.
Lee, Daewoo,Li, Ming-Yu,Sui, Mao,Zhang, Quanzhen,Pandey, Puran,Kim, Eun-Soo,Lee, Jihoon Springer US 2015 NANOSCALE RESEARCH LETTERS Vol.10 No.1
<P>Metallic nanoparticles have been widely witnessed in many applications: serving as the catalysts for various nanowire systems, as the active mediums of various device applications, and also for the nanoscale templates for hybrid quantum structures. In the performance of devices and configurations of the resulting nanostructures, the size and density of nanoparticles play critical roles. In this paper, the control of self-assembled Au droplets on GaAs (100), (110), and (111) is systematically investigated through the variation of deposition amount (DA), annealing temperature (AT), and dwelling time (DT). Based on the Volmer–Weber growth model, the formation of Au droplets and dramatic evolution of Au nanostructures on various GaAs surfaces is observed from the Au clusters to the round-dome shapes with the AT variation between 250 and 550 °C. With the systematic DA control, a radical size and density evolution of Au droplets shows the size expansion of over 400 % in average height and 800 % in average lateral diameter, while the density shows over two orders of decrease. With the DT variation, the self-assembled Au droplets tend to grow larger due to the Ostwald ripening while a clear distinction among the surface indexes is observed.</P><P><B>Electronic supplementary material</B></P><P>The online version of this article (doi:10.1186/s11671-015-0950-z) contains supplementary material, which is available to authorized users.</P>
Suh, Daewoo,Lee, Sanghoon,Mun, Hyeona,Park, Sung-Hoon,Lee, Kyu Hyoung,Wng Kim, Sung,Choi, Jae-Young,Baik, Seunghyun Elsevier 2015 Nano energy Vol.13 No.-
<P><B>Abstract</B></P> <P>Solution-based synthesis of thermoelectric nanoplates, which provides a low thermal conductivity due to the grain boundary scattering, has received considerable attention as a scalable method. However, the scattering also decreased electrical conductivity leading to a low thermoelectric figure of merit (<I>ZT</I>). Here we employed expanded graphene to enhance thermoelectric performance of p-type Bi<SUB>0.5</SUB>Sb<SUB>1.5</SUB>Te<SUB>3</SUB> composites by simultaneous improvement in electrical conduction and phonon scattering. The addition of expanded graphene (0.1vol%) improved both carrier concentration and electrical conductivity of composites due to the high intrinsic p-type carrier concentration of graphene. Besides, it significantly decreased lattice thermal conductivity due to the phase boundary phonon scattering in spite of the high intrinsic thermal conductivity of graphene. The increased carrier concentration also suppressed the bipolar conduction resulting in a moderate increase in power factor and a slow increase in bipolar thermal conductivity at elevated temperatures. Overall, the maximum <I>ZT</I> increased by 45% (1.13 at 360K) by the addition of expanded graphene. A similar trend with a greater maximum <I>ZT</I> (1.24 at 360K) was observed when ball-milled Bi<SUB>0.5</SUB>Sb<SUB>1.5</SUB>Te<SUB>3</SUB> ingot powders were employed providing reliability of the suggested mechanism.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Thermoelectric properties of graphene-Bi<SUB>0.5</SUB>Sb<SUB>1.5</SUB>Te<SUB>3</SUB> composites prepared by the powder metallurgy were investigated. </LI> <LI> The addition of expanded graphene (0.1vol%) enhanced thermoelectric performance of the p-type Bi<SUB>0.5</SUB>Sb<SUB>1.5</SUB>Te<SUB>3</SUB> composites by simultaneous improvement in electrical conduction and phonon scattering. </LI> <LI> The maximum <I>ZT</I> increased by 45% (1.13 at 360K) by the inclusion of expanded graphene. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
암모니아 수용액(Urea) 분사 맵 구성을 위한 SCR 촉매특성 및 NOx 저감효과에 관한 연구
남대우(Daewoo Nam),강정호(Jeongho Kang),정건우(Gunwoo Jeong),김용태(Youngtae Kim),김태민(Taemin Kim),이해수(Haesoo Lee),김상훈(Changhee Kim),김창희(NaeHyun Lee) 한국자동차공학회 2010 한국자동차공학회 부문종합 학술대회 Vol.2010 No.5
In order to form the basic map for the urea mass flow rate in Urea-SCR system, DOC/DPF and SCR was installed, then injection test was performed at various engine conditions. First of all, pre-map was comprised from the result of the space velocity and the NO₂/NOx ratio. As the result of experiment, it is shown that the NO₂/NOx ratio and the active region of SCR catalyst according to exhaust temperature have largely effect on forming the map of urea mass flow rate. And, in the case of increasing NH3/NOx ratio, NOx conversion is improved, but the NH₃ slip occurs according to increasing NH₃/NOx ratio, which is the factor to limit the region of the urea mass flow rate as well. Then, in case to inject the urea following the map, NOx is decreased about 65%. Although different aspects are shown due to many effect like high temperature, space velocity, NO2/NOx ratio, it is expected to satisfy emission standard EURO-V through the optimization of urea mass flow rate.
모바일 환경 기반의 소프트웨어 스트리밍 시스템을 위한 선인출 기법의 설계 및 구현
이대우 ( Daewoo Lee ),박선영 ( Seon-yeong Park ),김진수 ( Jin-soo Kim ),맹승렬 ( Seung-ryoul Maeng ) 한국정보처리학회 2006 한국정보처리학회 학술대회논문집 Vol.13 No.1
온디맨드 소프트웨어 스트리밍(On-Demand Software Streaming)이란 서버가 제공하는 소프트웨어를 클라이언트에 설치하지 않고 실행하는 기술로, 서버로부터 필요한 부분만 스트리밍으로 전송 받아 실행하는 기술을 말한다. 이 기술을 이용하면 소프트웨어 제공자는 소프트웨어 관리를 용이하게 할 수 있고, 소프트웨어 사용자는 적은 저장 공간으로 많은 소프트웨어를 사용할 수 있다는 이점을 얻게 된다. 하지만 모바일 환경에서 이를 이용하는 경우에는, 느린 무선 네트워크를 통해 소프트웨어 이미지를 전송해야 하기 때문에 소프트웨어 실행 속도가 매우 느리다는 문제가 생긴다. 이를 해결하기 위해서 본 논문에서는 온디맨드 소프트웨어 스트리밍을 사용하는 시스템의 성능 향상을 위해 효율적인 선인출 기법을 설계하고 실제로 구현하였다. 실험 결과, 애플리케이션이 데이터를 읽을 때 걸리는 시간이 무선랜 환경에서는 평균 50%, CDMA 환경에서는 평균 20% 정도 감소했으며, 특히 네트워크 지연시간이 증가할수록 더 많이 감소하였다.
상수도열원과 지열원을 이용한 동절기 지열히트펌프 성능평가에 대한 연구
이병두(Lee, Byoungdoo),이세진(Lee, Sejin),이대우(Lee, Daewoo) 한국신재생에너지학회 2011 한국신재생에너지학회 학술대회논문집 Vol.2011 No.05
본 연구에서는 지열히트펌프 시스템의 열원으로써 지열이외에 건축물의 미활용 에너지라고 할 수 있는 상수도의 에너지를 활용하여 지중열교환기의 천공길이를 줄이는 것이 주요 목적이며, 또한 건물의 미활용에너지를 냉난방에너지원으로써 이용 가능한 것을 보여주는 것에 있다. 실험은 4인 가족기준으로 3RT 용량의 히트펌프를 설치하고 인당 평균 177 liter/day 기준으로 하루에 약 710 liter/day의 물을 사용하는 것으로 가정하였다(환경부 2007년 상수도 통계값). 시간당 가정내에서 사용하는 물량은 일정하지 않아 일일 8시간 사용하는 것으로 하여 약 1.5 LPM 으로 실험하였다. 저수조의 크기 및 지열 히트펌프의 열원으로써 사용가능한 열량을 계산하기 위해 CFD 시물레이션을 수행하였다. CFD의 결과 상수도를 급수하기 위한 저수조의 크기는 2m³로 결정하였으며 이때 열원으로써 사용가능한 열량은 약 0.7RT였다. 48시간의 실험기간 동안 저수조를 통해 얻은 열원은 0.6RT 였으며 100m의 지중열교환기를 통해 얻은 열원은 2RT 였다. 히트펌프 자체의 난방 COP는 평균 4.2를 나타내었으며 펌프등의 소비전력을 포함한 System COP는 4.0 나타내었다. 이번 연구를 통해 건물의 미활용에너지인 저수조의 물을 이용하여 지열히트펌프의 열원으로써 이용 가능하며 기존의 지열히트펌프 시스템대비 천공길이 단축, 시공비 저감이 가능한 것을 볼 수 있었다.