세관 양광주 방전에서 플라즈마 확산의 완전 해

김동준,정종문,김정현,황하청,정재윤,조윤희,임현교,구제환,최은하,조광섭,Jin, D.J.,Jeong, J.M.,Kim, J.H.,Hwang, H.C.,Chung, J.Y.,Cho, Y.H.,Lim, H.K.,Koo, J.H.,Choi, E.H.,Cho, G.S. 한국진공학회 2010 Applied Science and Convergence Technology Vol.19 No.1

관경이 수 mm인 세관 램프 내부에서 플라즈마의 확산을 조사하기 위하여 이극성(ambipolar) 확산방정식을 해하였다. 반경 방향의 확산에 의한 유리관 벽에서의 플라즈마 소멸 특성시간은 $\tau_r\;=\;(r_0/2.4)^2/D_a$로 주어진다. 반경 $r_0{\sim}1\;mm$이고 이극성 확산계수 $D_a{\sim}0.01\;m^2/s$ 이면, $\tau_r{\sim}17\;{\mu}s$이다. 이는 램프의 교류전원 구동에서 플라즈마를 유지하기 위한 구동 최소 주파수 ~30 kHz에 해당한다. 고전압이 인가되는 전극부에 발생한 고밀도의 플라즈마가 양광주로 확산되는 특성시간은 $\tau_z{\sim}0.1\;s$이다. 고밀도 플라즈마 경계에서의 시간에 대한 확산속도는 $t{\sim}10^{-6}\;s$일 때 $u_D{\sim}10^2\;m/s$이고, $t{\sim}10^{-3}\;s$이면 그 속도는 $u_D{\sim}1\;m/s$로 느려진다. 따라서 램프 길이 ~1 m에 대하여 전극부에서 생성된 고밀도 플라즈마가 양광주 전체로 확산되는 시간은 수 초가 걸린다. The ambipolar diffusion equation has been solved in a fine-tube lamp of a few mm in diameter. In the diffusion of radial direction, the plasma diffuses and vanishes away at the glass wall by recombination with the characteristic time of plasma loss is given by $\tau_r\;=\;(r_0/2.4)^2/D_a$. With the radius $r_0{\sim}1\;mm$ and the ambipolar diffusion coefficient $D_a{\sim}0.01\;m^2/s$, the vanishing time is calculated $\tau_r{\sim}10\;{\mu}s$ which corresponds to the least value of frequency 30 kHz for the sustaining the plasma in the operation of high voltage AC-power. In the diffusion of longitudinal z-direction, a high density plasma generated at the area of a high voltage electrode, diffuses into the positive column with the characteristic time $\tau_z{\sim}0.1\;s$. The plasma diffusion velocity at the boundary of high density plasma is $u_D{\sim}10^2\;m/s$ at the time $t{\sim}10^{-6}$ s and the diffusion velocity becomes slow as $u_D{\sim}1\;m/s$ at $t{\sim}10^{-3}\;s$. Therefore, for the long lamp of 1 m, it takes about several seconds for the high density plasma at the area of electrode to diffuse through the whole positive column space.

Rhizome Germination Rate of Miscanthus x giganteus at Different Rhizome Sizes

( Chung Y. S. ),( M. Park ),( S. Lee ) 강원대학교 농업생명과학연구원(구 농업과학연구소) 2018 강원 농업생명환경연구 Vol.30 No.2

Miscanthus is a perennial rhizomatous grass that originated in the tropics and subtropics, although different species are found throughout a wide climatic range. In general, Miscanthus are grown from rhizomes under greenhouse conditions and subsequently transplanted into the field. To manage plants well, it is important to have uniform germination. However, the impact of rhizome size on the germination rate of Miscanthus species has not been thoroughly studied. The impact of rhizome size on germination rate and germination days was therefore investigated in three Miscanthus species (M. sinensis, M. sacchariflorus, and M. x giganteus). There was no considerable variation in germination days between the three Miscanthus species studied. However, the germination rate varied depending on rhizome size. Rhizome size does not affect the germination rate of M. sacchariflorus; thus, small rhizomes can be used for planting. The results of this study suggest the use of 15-20 g of rhizomes for M. giganteus and M. sinensis to ensure a 100% rate of germination.

[S9-1] Anti-diabetic Effects of Two Variants of Korean Arlemisia princeps Pampanini Cultivated in Ganghwa Island

U.J. Jung,N-I. Bae,H-G. Chung,M-H. Bang,J-S. Yoo,T-S. Jeong,K-T. Lee,Y-J. Kang,M-K. Lee,S-N. Ryu,M-S. Choi 한국식품영양과학회 2006 한국식품영양과학회 학술대회발표집 Vol.2006 No.10

M-13 bacteriophage based structural color sensor for detecting antibiotics

Moon, J.S.,Park, M.,Kim, W.G.,Kim, C.,Hwang, J.,Seol, D.,Kim, C.S.,Sohn, J.R.,Chung, H.,Oh, J.W. Elsevier Sequoia 2017 Sensors and actuators. B Chemical Vol.240 No.-

Color sensor systems that exploit the advantages of M-13 bacteriophage have been shown to be potentially useful for detection of hazardous materials. The properties of M-13 bacteriophage can be systemically modified to impart target-specific selectivity and sensitivity using the phage display technique. Here, we describe a structural color-based sensor that utilizes genetically engineered M-13 bacteriophage to discriminate different types of antibiotics. An M-13 bacteriophage based structural color matrix was fabricated using a simple pulling technique by self-assembly of M-13 bacteriophage. When exposed to organic solvent, M-13 bacteriophage bundles promptly swell and promote distinct structural color change. Color sensors composed of M-13 bacteriophage genetically engineered to possess WHW peptide motifs clearly discriminated three different types of antibiotics, which was based on the color analysis of sensor using principal component analysis. Our sensing approach based on M-13 bacteriophage could be a promising sensor technique such as an environmental monitoring system.

Experimental investigation of Wheeler's hardening model for Pusan clays

Chung, S.G.,M. Suneel,K.N. Prasad,Rao, K.G. 東亞大學校建設技術硏究所 2004 硏究論文集 Vol.28 No.1

The present paper adopts Wheeler's model (1997) to evaluate its application to Pusan clays. A program of triaxial and consolidation tests on samples of Pusan clays at Yangsan, Korea was under taken to investigate the applicability of the model adopted. The model parameters are evaluated by describing the initial state of the soil. Model predictions are shown to be qualitatively consistent with experimental observations, but refinement seems to be required to have much better agreement between experimental results and model predictions.

Lipopolysaccharide from <i>Prevotella nigrescens</i> stimulates osteoclastogenesis in cocultures of bone marrow mononuclear cells and primary osteoblasts

Chung, Y.-H.,Chang, E.-J.,Kim, S.-J.,Kim, H.-H.,Kim, H.-M.,Lee, S.-B.,Ko, J. S. Blackwell Publishing Ltd 2006 Journal of periodontal research Vol.41 No.4

<P>Background and Objective: </P><P>Lipopolysaccharide is thought to be a major virulence factor of pathogens associated with periodontal diseases and is believed to stimulate bone resorption <I>in vivo</I>. Although <I>Prevotella nigrescens</I> has been implicated in periodontitis, its role in osteoclastogenesis has not been reported. In this study, we investigated the effects of lipopolysaccharide from <I>P. nigrescens</I> on the formation of osteoclasts and the production of cytokines related to osteoclast differentiation.</P><P>Material and Methods: </P><P>Mouse bone marrow mononuclear cells were cultured in the presence of macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor &kgr;B ligand (RANKL), with or without lipopolysaccharide. Bone marrow mononuclear cells were also cocultured with calvarial osteoblastic cells in the presence or absence of lipopolysaccharide. Osteoclast formation was determined by tartrate-resistant acid phosphatase cytochemistry. The production of osteoprotegerin (OPG), M-CSF, tumor necrosis factor alpha (TNF-&agr;), transforming growth factor-beta (TGF-&bgr;) and prostaglandin E<SUB>2</SUB> (PGE<SUB>2</SUB>) was determined by enzyme-linked immunosorbent assay (ELISA).</P><P>Results: </P><P><I>P. nigrescens</I> lipopolysaccharide inhibited osteoclast differentiation from bone marrow mononuclear cells cultured in the presence of M-CSF and RANKL. However, in the coculture system, <I>P. nigrescens</I> lipopolysaccharide stimulated osteoclastogenesis. Notably, <I>P. nigrescens</I> lipopolysaccharide decreased OPG production but increased TGF-&bgr; secretion. In addition, treatment with <I>P. nigrescens</I> lipopolysaccharide increased PGE<SUB>2</SUB> production during the late stage of the culture period. There was no difference in M-CSF and TNF-&agr; production.</P><P>Conclusion: </P><P>These results demonstrate that <I>P. nigrescens</I> lipopolysaccharide stimulates osteoclastogenesis in the coculture system by decreasing the production of OPG and increasing the production of TGF-&bgr; and PGE<SUB>2</SUB>. Through the mechanisms involving these factors, <I>P. nigrescens</I> lipopolysaccharide may cause alveolar bone resorption in periodontal diseases.</P>

Geological and Geotechnical Characteristics of Marine Clay in Busan New Port

Chung, S.G,E. Ninjgarav,M. Suneel,K.Ganapathi Rao,Kim, G.J. 東亞大學校 建設技術硏究所 2005 硏究論文集 Vol.28 No.2

Since early 1990s reclamation projects for Busan and its vicinity in Nakdong River plain have been performed for industrial and residential complexes. As well it has started to build a new port (Busan Newport) with increase in overloads of Busan port since late 1990s. In the area the sedimentary deposit is composed of soft clay of about 30m thick, thin sand layer of 3-4m thick, hard clayey soil, and then basal conglomerates and sandy sediments, total thickness of which is about 70m at maximum under seawater. For the huge project many contract companies have simultaneously performed geotechnical investigations to get design parameters. Based on the harmful experiences gained by the previous projects, it was also required to pay careful attention to sampling and laboratory and field tests for theproject. Nevertheless the results of laboratory tests were so scattered and then resulted in difficulty to evaluate the design parameters. Existing data has been reviewed to evaluate the validity or cause of their variation. In addition geological study, sampling and soil tests have been carefully carried out at a few locations. Using the results the clay would be effectively characterized for depositional environment and its relation to soil properties.

OGLE-2015-BLG-1482L: The First Isolated Low-mass Microlens in the Galactic Bulge

Chung, S.-J.,Zhu, W.,Udalski, A.,Lee, C.-U.,Ryu, Y.-H.,Jung, Y. K.,Shin, I.-G.,Yee, J. C.,Hwang, K.-H.,Gould, A.,Albrow, M.,Cha, S.-M.,Han, C.,Kim, D.-J.,Kim, H.-W.,Kim, S.-L.,Kim, Y.-H.,Lee, Y.,Park, American Astronomical Society 2017 The Astrophysical Journal Vol.838 No.2

<P>We analyze the single microlensing event OGLE-2015-BLG-1482 simultaneously observed from two ground-based surveys and from Spitzer. The Spitzer data exhibit finite-source effects that are. due to the passage of the lens close to or directly over. the surface of the source star as seen from Spitzer. Such finite-source effects generally yield measurements of the angular Einstein radius, which when combined with the microlens parallax derived from a comparison between the ground-based and the Spitzer light curves. yields the lens mass and lens-source relative parallax. From this analysis, we find that the lens of OGLE-2015-BLG-1482 is a very low-mass star with a. mass 0.10 +/- 0.02 M-circle dot or a brown dwarf with a. mass 55 +/- 9MJ, which are. located at D-LS = 0.80 +/- 0.19 kpc and D-LS = 0.54 +/- 0.08 kpc, respectively,. where DLS is the distance between the lens and the source, and thus it is the first isolated low-mass microlens that has been decisively located in the Galactic bulge. The degeneracy between the two solutions is severe ( Delta chi(2) = 0.3). The fundamental reason for the degeneracy is that the finite-source effect is seen only in a single data point from Spitzer, and this single data point gives rise to two solutions for rho, the angular size of the source in units of the angular Einstein ring radius. Because the rho degeneracy can be resolved only by relatively high-cadence observations around the peak, while the Spitzer cadence is typically similar to 1 day(-1), we expect that events for which the finite-source effect is seen only in the Spitzer data may frequently exhibit this rho degeneracy. For OGLE-2015-BLG-1482, the relative proper motion of the lens and source for the low-mass star is mu(rel) = 9.0 +/- 1.9 mas yr(-1), while for the brown dwarf it is 5.5 +/- 0.5 mas yr(-1). Hence, the degeneracy can be resolved within similar to 10 years from direct-lens imaging by using next-generation instruments with high spatial resolution.</P>

Investigations in to the Capacity and Strength of Rhizome Germination in Three Different Miscanthus Species

( Chung Y. S. ),( M. Park ),( S. Lee ) 강원대학교 농업생명과학연구원(구 농업과학연구소) 2018 강원 농업생명환경연구 Vol.30 No.2

Miscanthus is a perennial rhizomatous grass. Among Miscanthus species, M. sinensis, M. sacchariflorus, and M. x giganteus and their varieties are widely planted worldwide. However, M. x giganteus must be propagated vegetatively owing to its sterility. Therefore, its propagation poses significant challenges both economically and to production efficiency. Most M. x giganteus is propagated by rhizomes that form nodes, internodes, and buds in a similar manner to above-ground stems. Therefore, we investigated the germination rate and strength of three different Miscanthus species, M. sinensis, M. sacchariflorus, and M. x giganteus. We found that, of these species, M. sacchariflorus performed best in terms of both germination rate and strength. The results of the current study could provide the starting point for further and extensive study of rhizome germination in Miscanthus species.

Raised Source-Drain Transistors in a Cell and Support Area with Co-Silicide for 88-nm DRAM Technology and Beyond

Y.M. Choi,B.J. Park,D.H. Kim,D.I. Kim,D.S. Hwang,H. K. Hwang,H.J. Kim,H.S. Kim,I.B. Chung,J.M. Park,J.W. Lee,J.Y. Kim,Kinam Kim,M.H. Jo,정문영,N.J. Kang,S.E. Kim,Y.J. Park,Y.S. Hwang 한국물리학회 2004 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.44 No.1

Full integration of a 512-Mb dynamic random access memory (DRAM) using both a raised sourcedrain (S/D) in a cell and a support area with additional Co silicidation in the support area is successfully performed for the first time at an 88-nm technology node. The Co-silicided support transistors in the DRAM circuit can be made by using the silicidation-blocking-layer method which keeps the cell array from silicidation. Raised S/D transistors using Si selective epitaxial growth (SEG) demonstrate good short-channel eect (SCE) immunity and a Co-silicided S/D in the support transistors exhibits an excellent current driving capability and reduced S/D sheet resistance, even for very small dimensions.