The Effect of Bright Lenses on The Astrometric Observations of Gravitational Microlensing Events

Youngjin Jeong,Cheongho Han,Sung-Hong Park 한국천문학회 1999 天文學會報 Vol.24 No.1

Where Are the Binary source Gravitational Microlensing Events ?

Jeong Youngjin,Han Cheangho 한국천문학회 1998 天文學會報 Vol.23 No.-

Anti-inflammatory Effect of Columbianetin on Activated Human Mast Cells

Jeong, Hyun-Ja,Na, Ho-Jeong,Kim, Su-Jin,Rim, Hong-Kun,Myung, Noh-Yil,Moon, Phil-Dong,Han, Na-Ra,Seo, Jae-Uk,Kang, Tae-Hee,Kim, Jae-Joong,Choi, Youngjin,Kang, In-Cheol,Hong, Seung-Heon,Kim, You-Ah,Seo, Pharmaceutical Society of Japan 2009 BIOLOGICAL & PHARMACEUTICAL BULLETIN Vol.32 No.6

<P>In the present study, we extracted <I>Corydalis heterocarpa</I> with various solvents in order to find the bioactive constituents that demonstrated anti-inflammatory effects. We isolated the active compound, Columbianetin. Anti-inflammatory effect of Columbianetin has been reported but the precise effects of Columbianetin in experimental models have remained unknown. In the present study, we investigate the effect of Columbianetin on the production of histamine, interleukin (IL)-1β, IL-6, IL-8, and tumor necrosis factor (TNF)-α and expression of cyclooxygenase-2 (COX-2) by using the human mast cell line (HMC-1). Various concentrations of Columbianetin were treated before the activation of HMC-1 cells with phorbol 12-myristate 13-acetate (PMA) plus calcium ionophore, A23187. PMA plus A23187 significantly increased IL-1β, IL-6, IL-8, and TNF-α production compared with media control (<I>p</I><0.05). We also show that the increased cytokines IL-1β, IL-6, IL-8, and TNF-α level was significantly inhibited by Columbianetin in a dose-dependent manner (<I>p</I><0.05). Maximal inhibition rates of IL-1β, IL-6, IL-8, and TNF-α production by Columbianetin were about 102.6%, 101.1%, 95.8%, and 103.9%, respectively. Columbianetin inhibited expression of COX-2. In addition, the effect of Columbianetin was investigated on the histamine release from HMC-1 stimulated by substance P, which promotes histamine release. Columbianetin also inhibited the histamine release by substance P. In conclusion, these results indicate that Columbianetin may be helpful in regulating mast cell-mediated allergic inflammatory responses.</P>

Carbon Nanotube Film for Stretchable Conductor

Youngjin Jeong,Yunjea Hwang,Seunghyuk Lee,Yeonjae Oh,Hyunwoong Oh 한국고분자학회 2016 한국고분자학회 학술대회 연구논문 초록집 Vol.41 No.2

Effect of Ar Flow Ratio on the Characteristics of Ga-Doped ZnO Grown by RF Magnetron Sputtering

정영진(Jeong, Youngjin),이승진(Lee, Seungjin),손창식(Son, Changsik) 한국신재생에너지학회 2011 한국신재생에너지학회 학술대회논문집 Vol.2011 No.11

The structural, optical, and electrical properties of Ga-doped ZnO (GZO) thin films on glass substrates grown by radio-frequency(RF) magnetron sputtering were investigated. The flow ratio of Ar was varied as a deposition parameter for growing high-quality GZO thin films. The structural properties and surface morphologies of GZO were characterized by the X-ray diffraction. To analyze the optical properties of GZO, the optical absorbance was measured in the wavelength range of 300-1100 nm by using UV-VIS spectrophotometer. The optical transmittance, absorption coefficient, and optical bandgap energy of GZO thin films were calculated from the measured data. The crystallinity of GZO thin films is improved and the bandgap energy increases from 3.08 to 3.23eV with the increasing Ar flow ratio from 10 to 100 sccm. The average transmittance of the films is over 88% in the visible range. The lowest resistivity of the GZO is 6.215{times}10^{-4}{Omega}{cdot}cm and the hall mobility increases with the increasing Ar flow ratio. We can optimize the characteristics of GZO as a transparent electrode for thin film solar cells by controlling Ar flow ratio during deposition process.

Mesoporous MFI zeolites as high performance catalysts for Diels-Alder cycloaddition of bio-derived dimethylfuran and ethylene to renewable <i>p</i>-xylene

Kim, Jeong-Chul,Kim, Tae-Wan,Kim, Youngjin,Ryoo, Ryong,Jeong, Soon-Yong,Kim, Chul-Ung Elsevier 2017 Applied Catalysis B Vol.206 No.-

<P><B>Abstract</B></P> <P>Zeolite solid-acid catalyst can produce <I>p</I>-xylene (PX) <I>via</I> a renewable synthetic route through Diels-Alder cycloaddition and dehydration reactions of bio-derived 2,5-dimethylfuran (DMF) and ethylene (DMF-to-PX). Here, to find a key factor in the physicochemical properties of a zeolite catalyst, we synthesized a series of mesoporous MFI zeolite nanosheets with systematically controlled thickness (2.5 and 7.5nm) and silica-alumina ratio (Si/Al=48–340) as well-defined model catalysts for PX production. From the catalytic results using these MFI zeolite nanosheets and conventional MFI zeolites, PX production yield was found to be strongly related to zeolite crystal thickness and concentration of Brønsted acid sites of the MFI zeolite catalysts. The MFI zeolite nanosheet with small thickness provided high PX production due to the presence of Brønsted acid sites on the exterior surface and facile mass transfer of aromatic compounds through mesopores. To verify these catalytic factors and to apply it to commercially available zeolite, a mesoporous MFI zeolite was prepared from a commercial ZSM-5 zeolite <I>via</I> a simple post-treatment process; mesoporous MFI-type zeolites were tested in the DMF-to-PX reaction. This mesoporous MFI zeolite exhibited a superior PX yield (75.8%) with high DMF conversion and PX selectivity compared with those characteristics of pristine MFI zeolite (PX yield=8.4%).</P> <P><B>Highlights</B></P> <P> <UL> <LI> Nanosheet MFI zeolites (NS-MFI) were synthesized with different crystal thickness and Si/Al ratios. </LI> <LI> NS-MFI were investigated as model catalysts for Diels-Alder cycloaddition reaction of 2,5-dimethylfuran and ethylene. </LI> <LI> <I>p</I>-Xylene production yield improved by the NS-MFI with small crystal thickness. </LI> <LI> The better PX production yield of NS-MFI is attributed to a large number of external Brønsted acid sites and mesopores. </LI> <LI> These catalytic factors can be extended to a commercial ZSM-5 zeolite catalyst. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

영역확장 방법을 적용한 3 차원 공간에서 견관절 분할

정영진(youngjin jeong),김정준(Kim Jeong Jun),이희성(Lee Hee Sung),서안나(Anna Seo) 한국HCI학회 2017 한국HCI학회 학술대회 Vol.2017 No.2

속리산국립공원의 나방류 다양성에 관한 연구

김영진(Youngjin Kim),한용구(Yong-Gu Han),최민주(Min-Joo Choi),정종철(Jong-Chul Jeong),홍의정(Eui-Jeong Hong)조영호(Youngho Cho) 국립공원연구원 2015 국립공원연구지 Vol.6 No.3

속리산국립공원 나방류 다양성 현지조사결과, 총 28과 373종 2,374개체가 확인되었으며, 과거 문헌자료를 포함하여 속리산국립공원의 나방류를 총 518종으로 정리하였다. 주요 조사지점별 출현 현황은 세심정 일대 27과 273종, 대목리 일대 26과 262종, 화양리 일대 26과 253종, 쌍곡리 일대 23과 205종, 사내리 일대 22과 203종, 상오리 일대 21과 190종이 조사되었다. 군집분석에 의한 전체 우점종은 청백무늬밤나방이 0.022의 우점도 지수로 나타났다. 종다양도 지수는 세심정 일대가 5.400으로 가장 높게 나타났으며 균등도는 전 조사지점이 0.962~0.969의 지수로 확인되었고, 풍부도는 세심정 일대가 43.684로 가장 높게 조사되었다. 중요 곤충자원으로는 한국고유생물종 2종, 환경부 특정종 24종, 국외반출승인대상생물종 7종이 확인되었다. From the Natural Resource Research in Songnisan National Park, Korea in 2011, A total of 28 families 373 species 2,374 individuals moths were identified. Consequently, the insects identified from previous studies and this survey become 518 species. By the survey point, Sesimjeong area was identified as the highest emergence as 27 families 273 species. Next was Daemok-ri area as 26 families 262 species, Hwayang-ri area as 26 families 253 species, Ssanggok-ri area as 23 families 205 species, Sanae-ri area as 22 families 203 species and then Sango-ri area as 21 families 190 species. The dominant species in survey point was as Ercheia niveostrigata in Songnisan National Park. An important insect resource were identified as 2 endemic species of Korea, 24 specific species of Ministry of Environment, Korea and 7 biological resources subject to permission for taking abroad species of Korea.

서울의 사라진 어처구니에 대한 고찰

정영진(Youngjin Jeong) 한국외국어대학교 역사문화연구소 2023 역사문화연구 Vol.86 No.-

서울에 남아 있는 옛 목조 건축물의 지붕을 장식하고 있는 어처구니는 중국의 영향을 받아 조선시대에 변형⸱토착화된 것으로서, 건물을 꾸미고 벽사(辟邪)의 기능을 하면서 건물의 위상을 상징하는 것이다. 특히 권력자와 관련된 건물의 어처구니의 개수는 관례상 건물의 위상과 규모가 클수록 많은데, 황제의 정전(正殿)의 추녀마루에는 11개가 배치되었다. 한편, 황궁우와 덕수궁 중화전 그리고 경복궁의 근정전과 경회루 지붕의 추녀마루에는 어처구니가 현재 각각 최고 6개와 9개 그리고 7개와 11개가 얹혀있지만, 각 건물이 지어진 초기에 촬영된 사진 속에는 각각 7개와 11개개 그리고 11개와 11개의 어처구니가 얹혀있었음을 확인할 수 있다. 현재 경회루와 근정전의 어처구니 개수 차이에 대해서는 황제국의 사신을 대접하는 건물과 제후국의 왕이 사용하는 건물의 위상 차이를 상징하는 것이라는 해석과 개즙⸱복원⸱보수과정에서 잘 못 배치된 것이라는 추측이 있다. 그러나 대원군 시기에 중창된 근정전과 경회루의 추녀마루 어처구니의 최고 개수는 황제를 상징하는 11개였다. 그러므로 이러한 사실은 대원군이 경복궁을 중창하면서 청나라의 정치적 영향권으로부터 독립하려는 의지를 근정전의 어처구니 개수로 표현하였던 것으로 추정된다. 이러한 추정은 창덕궁 인정전의 어처구니가 9개인 반면에 칭제이후에 지어진 舊⸱新중화전의 어처구니 개수는 11개였다는 사실로도 뒷받침될 수 있다. 잘 못 복원된 어처구니는 한국 역사와 문화에 대한 그릇된 해석을 야기할 수 있으므로 어처구니의 올바른 복원이 요망된다. Eocheogoony(Jabsang, 雜像) decoration on the roofs of Korean old wooden buildings in Seoul had been imported from the old China, modified and settled down in the early Chosen period. Eocheogoony decoration have functions of decorating the roof of the buildings, conjuring away wickedness and representing the status of the buildings as well. Especially, the number of Eocheogoony of a set gets bigger as the building user’s status gets higher; for example, the only official building of emperor could have sets of 11 Eocheogoonies on its roof hip rafters. And now, Whangkoongwoo, JoongwhaJeon, Keunjeongjeon and Kyoungwhoyroo have sets of maximumly 6, 8, 7 and 11 Eocheogoonies on their roof hip rafters respectively. However, the old photographs taken in the early period of the buildings show the numbers of 7, 11, 11 and 11 respectively. Presently, the reason of the maximumly 11 Eocheogoonies sets of Kyoungwhoyroo and 7 of Keunjeongjeon is explained as caused by the status difference between Kyoungwhoyroo for Chinese imperial envoy and Keunjeongjeon for the king of Chosen, or the result of inadequate restoration and repair. However, the maximumly 11 Eocheogoonies set of Keunjeongjeon which was rebuilt by Daewongoon could be interpreted as one of the representativeness of independent volition out of Chinese influence. This interpretation could be supported by the facts that the old and new Joongwhajeons, which were built after the imperial proclamation of Chosen, had the sets of 11 Eocheogoonies. Correct restorations of the historic buildings are needed because inadequate restorations could cause misconstrue about the history and culture of Korea.

화학 기계적 연마에 의한 리튬 니오베이트의 광학 특성에 관한 연구

정석훈(Sukhoon Jeong),김영진(Youngjin Kim),이현섭(hyunseop Lee),정해도(Haedo Jeong) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5

Lithium niobate (LN:LiNbO₃) is a compound of niobium, lithium and oxygen. The characteristics of LN are piezoelectricity, ferroelectricity and photoelectricity, and which is widely used in widely surface acoustic wave (SAW). To manufacture LN device, the LN surface should be a smooth surface and defect-free because of optical property, but the LN material is processed difficult by traditional processes such as grinding and mechanical polishing (MP) because of its brittleness. To decrease defects, chemical mechanical polishing (CMP) was applied to the LN wafer. In this study, the suitable parameters such as down force and relative velocity, were investigated for the LN CMP process. To improve roughness, the LN CMP was performed using the parameters that were the highest removal rate among process parameters. And, evaluation of optical property was performed by the optical reflectance and non-linear characteristic.