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.

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.

Selective hydrogenation of d-glucose to d-sorbitol over HY zeolite supported ruthenium nanoparticles catalysts

Mishra, D.K.,Dabbawala, A.A.,Park, J.J.,Jhung, S.H.,Hwang, J.S. Elsevier Science Publishers 2014 CATALYSIS TODAY - Vol.232 No.-

HY zeolite (HYZ) supported ruthenium (Ru) nanoparticles catalyst (Ru/HYZ) is prepared by simple impregnation method and is characterized by using energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), CO chemisorption and inductively coupled plasma (ICP) mass spectrometry. The catalyst Ru/HYZ is evaluated in hydrogenation of d-glucose and hydrogenation experiments to produce a selective product d-sorbitol were conducted batch wise in a three-phase laboratory scale reactor. The kinetics studies of d-glucose hydrogenation using the catalyst Ru/HYZ were carried out. In the operating regime studied the rate of reaction showed first orders dependency with respect to d-glucose and hydrogen. For affording maximum d-glucose conversion, yield and selectivity to d-sorbitol, the reaction conditions were also optimized.

Valeriana officinalis extract and its main component, valerenic acid, ameliorate d-galactose-induced reductions in memory, cell proliferation, and neuroblast differentiation by reducing corticosterone levels and lipid peroxidation

Nam, S.M.,Choi, J.H.,Yoo, D.Y.,Kim, W.,Jung, H.Y.,Kim, J.W.,Kang, S.Y.,Park, J.,Kim, D.W.,Kim, W.J.,Yoon, Y.S.,Hwang, I.K. Pergamon Press ; Elsevier Science Ltd 2013 Experimental Gerontology Vol.48 No.11

Valeriana officinalis is used in herbal medicine of many cultures as mild sedatives and tranquilizers. In this study, we investigated the effects of extract from valerian root extracts and its major component, valerenic acid on memory function, cell proliferation, neuroblast differentiation, serum corticosterone, and lipid peroxidation in adult and aged mice. For the aging model, d-galactose (100mg/kg) was administered subcutaneously to 6-week-old male mice for 10weeks. At 13weeks of age, valerian root extracts (100mg/kg) or valerenic acid (340μg/kg) was administered orally to control and d-galactose-treated mice for 3weeks. The dosage of valerenic acid (340μg/kg), which is the active ingredient of valerian root extract, was determined by the content of valerenic acid in valerian root extract (3.401+/-0.066mg/g) measured by HPLC. The administration of valerian root extract and valerenic acid significantly improved the preferential exploration of new objects in novel object recognition test and the escape latency, swimming speeds, platform crossings, and spatial preference for the target quadrant in Morris water maze test compared to the d-galactose-treated mice. Cell proliferation and neuroblast differentiation were significantly decreased, while serum corticosterone level and lipid peroxidation in hippocampus were significantly increased in the d-galactose-treated group compared to that in the control group. The administration of valerian root extract significantly ameliorated these changes in the dentate gyrus of both control and d-galactose-treated groups. In addition, valerenic acid also mitigated the d-galactose-induced reduction of these changes. These results indicate that valerian root extract and valerenic acid enhance cognitive function, promote cell proliferation and neuroblast differentiation, and reduce serum corticosterone and lipid peroxidation in aged mice.

z-방향으로 비등방적인 원통형 결함을 가진 YBCO 단결정의 자속운동

심성엽,황태종,김동호 嶺南大學校 基礎科學 硏究所 1998 基礎科學硏究 Vol.18 No.-

We have made a comparison of the magnetic properties between columnar defect introduced YBCO single crystal(S#1) and partially introduced crystal(S#2).Magnetization vs. applied field curves of S#1 had larger width than S#2 by SQUID magnetometer measurement. But if we considered the volume of partially introduce columnar defect in S#2, the curves of magntization of S#1 and S#2 showed nearly same magnitude. Moreover, S#1 and S#2 showed same normalized relaxation rate thus we may concluded that only the part of columnar defect contrubute the flux pinning in S#2. Irreversibility line(IRL)was obtained from AC susceptibility measurement. IRL of S#2 showed downward shift relative to the case of S31. Below the Bcr, exponent αwas 1.85 and 1.68 in the S#2, respectively. Bose-glass phase was even showed in the case of S#2 defect structure.

비타민 D3 의 경구투여 또는 자외선 조사가 브로일러 병아리의 증체 및 비타민 D3 대사에 미치는 영향

장윤환(Y . H . Chiang),황선일(S . I . Hwang),김중달(J . D . Kim),M . F . Holick(M . F . Holick) 한국영양사료학회 1995 韓國營養飼料學會誌 Vol.19 No.6

RF 스위치 적용을 위한 박막 PZT 엑추에이터의 d<SUB>31</SUB> 구동과 d<SUB>33</SUB> 구동 특성 비교

신민재(M. J. Shin),서영호(Y. H. Seo),최두선(D-S. Choi),황경현(K-H. Hwang) 한국정밀공학회 2006 한국정밀공학회 학술발표대회 논문집 Vol.2006 No.5월

In this work, we present the comparison between d<SUB>31</SUB> and d<SUB>33</SUB> mode characterization using the PZT micro-actuator for large displacement. The PZT micro-actuator consisted of Si, PZT, and Pt layer on SOI wafer. The electrode shapes were laminated and interdigitated for d<SUB>31</SUB> and d<SUB>33</SUB> mode, respectively. In order to characterize the actuation mode, we measured the displacement using laser interferometer. The maximum displacement of d<SUB>31</SUB> mode was 12.2㎛ at 10V, the actuation characterization of d<SUB>31</SUB> was better than that of d<SUB>33</SUB> mode. We estimated that displacement of d<SUB>33</SUB> mode would be larger than that of d<SUB>31</SUB> above 30V.

protoplast-fusion에 依한 澱粉에서 Ethanol의 單段醱酵能 酵母 開發 : I. Characteristics of two yeast strains and conditions for the protoplast formation and reeneration as a preliminary step in interspecific protoplast-fusion I. Interspecific Protoplast-fusion 을 爲한 酵母菌林의 諸特性과 Protoplast 調製 및 Regeneration 條件

吳秉夏,黃殷成,李炯周,李啓瑚,朴官和,張海東,徐鉉昌 서울大學校農科大學 1984 서울대농학연구지 Vol.9 No.1

澱粉으로 부터의 alcohol 醱酵能을 增進시키기 爲하여 澱粉糖化性 菌株인 Saccharomyces diastaticus와 優秀한 alcohol 醱酵性 菌株인 Saccharomyces uvarum을 母菌株로 하여 이들간의 同屬異種間 原形質融合(interspecific protoplast fusion)을 通한 優秀한 澱粉醱酵 性 alcohol 生産性 菌株를 새로이 開發할 目的에서 다음과 같은 一漣의 實驗結果를 얻었다. S. diastaticus의 醱酵液과 S. diastaticus+S. uvarum 混合醱酵液의 風味特性등을 確認하였다. 風味成分 抽出은 methylene chloride와 diethylether를 가지고 neutral flavor fraction과 acidic flavor fraction으로 나누었고 gas chromatography를 通하여 同定 및 定量하였다. Neutral flavor fraction의 경우 S. diastaticus+S. uvarum 混合醱酵液이 S. diastaticus 醱酵液보다, ester成分中에서는 ethyl acetate와 ethyl undecanoate가 더 많았고, alcohol 成分中에서는 n-propanol과 n-butanol이 더 많았다. Acidic flavor fraction의 경우 C??~C?? fatty acid가 同定 및 定量되었는데 S. diastaticus+S. uvarum 混合醱酵液이 S. diastaticus 醱酵液보다 lauric acid, caprylic acid, capric acid 含量이 두드러지게 많았다. S. diastaticus의 glucoamylase 生産性, glucoamylase의 分離 精製, 酵素力價 그리고 酵素學的 特性에서 optimum pH는 5.0, optimum temperature는 55℃ 이었다. S. diastaticus와 S. uvarum을 母菌株로 이들 간의 protoplast fusion을 위한 基礎的인 硏究로서 두 菌株의 諸特性과 protoplast調製의 最適條件을 決定하고 protoplast의 regeneration 條件의 確立을 도모하였다.두 菌의 生育曲線에서 모두 培養開始 7~8 時間만에 對數期 中期에 到達되었으므로 protoplast 調製는 이 時期의 細胞를 쓰기로 하였다. Generation time은 S. diastaticus가 1.04, S. uvarum이 1.38 時間이었다. 細胞의 크기는 S. diastaticus 44.10?㎛³, S. uvarum 99.67㎛³로 S. uvarum이 2倍나 컸다. DNA 含量은 細胞 當 S. diastaticus 44.3fg, S. uvarum 37.6fg이었다. 30% glucose 및 soluble starch에 대한 두 菌株의 ethanol 醱酵能은 glucose에 對하여 S. uvarum 11.4%, S. diastaticus 8.9% 이었고 soluble starch에 對하여는 S. diastaticus 만이 6.9%이었다. 두 菌株는 generation time, 細胞크기 및 DNA 含量 等으로 보아 diploid strain임을 알 수 있었고, 融合株 選拔을 위한 marker 로는 Sacch. uvarum의 melibiose 資化能의 차이를 利用할 수 있음을 밝혔다. Protoplast의 調製에는 β-glucuronidase와 Zymoyase를 使用하였는데 두 酵素 反應最適條件은 β-glucuronidase는 pH 8.0에서 10% 濃度의 溶液으로, Zymolyase는 pH7.5에서 20㎛/ml의 濃度의 溶液으로 하여 모두 70分間 處理하는 것으로 決定하였으나 이 정도의 處理時間에서는 protoplast가 극히 不安定하게 되어 regeneration frequency가 떨어지는 것을 確認하였으며, 特히 Zymolyase 處理로 얻어진 protoplast의 regeneration率이 낮은 것은 Zymolyase中에 不純物로 微量 混在한 protease가 protoplast의 노출된 membrane-bound protein을 分解함으로써 protoplast를 破壞시키기 때문인 것으로 추측되었다. 融合實驗에 利用할 수 있을 정도의 regeneration frequency를 얻기 위해서는 Zymolyase를 45分間 處理하여 얻은 protoplast를 1.5%의 polyvinylpyrrolicone이 加해진 OYPD培地에서 重層法으로 展開하여 regeneration시키는 것이 좋은 것으로 판명되었다. As preliminary steps of protoplast fusion between Saccharomyces diastaticus and S. uvarum to develop a fusant of higher ethanol production from starch, characteristics of the two presumptive parent strains, optimal conditions for protoplast preparation and conditions for highrer regeneration frequency were investigated. To determine flavor characteristics of the parent strains, neutral and acidic flavor fractions were extracted from liquids fermented by S. diastaticus and S. diastaticus + S. uvarum with methylene chloride and diethly ether. The liquid by the mixed culture produced more ethly acetate, ethyl undecanoate, n-propanol, n-butanol, lauric acid, caprylic acid and capric acid than that by S. diastaticus. Glucoamylase from S. diastaticus was purified and activity, productivity, and characteristics were determined. Optimum conditions for the enzyme were pH 5.0 and 55℃. The two strains reached logarithmic phase in 7-8h during growth and the generation time was 1.04 in S. diastaticus and 1.38 in S. uvarum. Cell size and DNA content per cell of S. diastaticus were 44.10㎛³and 44.3 fg, and for S. uvarum, 99.67㎛³and 37.6fg. Ethanol productivities of S. diastaticus were 8.9% from 30% glucose and 6.9% from 30% starch and 11.4% from glucose with S. uvarum. Through determination of generation time, cell size, and DNA content per cell, both strains appeared as diploids, and differences in assimilability of melibiose and soluble starch of the two strains were selected as markers to determine the fusant. The optimal condition for protoplast formation was treatment of both strains with 10% ß-glucuronidase at pH 8.0 or 20㎍/ml Zymolyase at pH 7.5 for 70 min. While the regeneration frequencies were very low at 70min exposure to Zymolyase because of the instability of protoplasts, the yeasts treated for 45min were better for regeneration. The regeneration frequencies were also enhanced by 3-6 times when the regeration was carried out with 1.5% polyvinylpyrrolidone which stabilized protoplasts.

간염 및 소아설사 바이러스질환에 대한 특이진단법 개발

윤재득,지영미,김기순,천두성,정윤석,박정구,황응수,김동수,정용석 국립보건연구원 1999 국립보건원보 Vol.36 No.-

Rational Design of Low Cost and High Energy Lithium Batteries through Tailored Fluorine-free Electrolyte and Nanostructured S/C Composite

Agostini, M.,Lim, D.-H.,Sadd, M.,Hwang, J.-Y.,Brutti, S.,Heo, J. W.,Ahn, J. H.,Sun, Y. K.,Matic, A. Wiley (John WileySons) 2018 ChemSusChem Vol.11 No.17

<P>We report a new Li-S cell concept based on an optimized F-free catholyte solution and a high loading nanostructured C/S composite cathode. The Li2S8 present in the electrolyte ensures both buffering against active material dissolution and Li+ conduction. The high S loading is obtained by confining elemental S (approximate to 80%) in the pores of a highly ordered mesopores carbon (CMK3). With this concept we demonstrate stabilization of a high energy density and excellent cycling performance over 500 cycles. This Li-S cell has a specific capacity that reaches over 1000 mA hg(-1), with an overall S loading of 3.6 mg cm(-2) and low electrolyte volume (i.e., 10 mu L cm(-2)), resulting in a practical energy density of 365 Wh kg(-1). The Li-S system proposed thus meets the requirements for large scale energy storage systems and is expected to be environmentally friendly and have lower cost compared with the commercial Li-ion battery thanks to the removal of both Co and F from the overall formulation.</P>