Calculations of AC magnetic losses from the experimental field profiles in various types of coated conductors under applied fields

Yoo, J,Lee, S,Jung, Y,Lee, J,Youm, D,Ha, H,Kim, H,Ko, R-K,Oh, S Institute of Physics 2008 Journal of physics. Conference series Vol.97 No.1

<P>We measured the field profiles, <I>H</I>(<I>x,H</I><SUB>a</SUB>) s, near the surface of coated conductors (CCs) by using the scanning Hall probe method. The samples were SmBCO-CC tape fabricated by co-evaporation method and YBCO-CC tape fabricated by PLD method. The applied fields, <I>H</I><SUB>a</SUB>s, were decreased from <I>H</I><SUB>peak</SUB>to -<I>H</I><SUB>peak</SUB> stepwise. From the values of <I>H</I>(<I>x,H</I><SUB>a</SUB>), we calculated the current profiles, <I>J</I>(<I>x,H</I><SUB>a</SUB>) s, by the inversion method. From the values of <I>J</I>(<I>x,H</I><SUB>a</SUB>) and the corresponding flux densities, we calculated the hysteretic energy losses per cycle, <I>Q</I><SUB>M</SUB>s, for various <I>H</I><SUB>peak</SUB>s. From the values of <I>Q</I><SUB>M</SUB>, we calculated the characteristic functions, <I>g</I>s, by using the relation, <I>g</I>= π<I>Q</I><SUB>M</SUB>/μ<SUB>0</SUB><I>I</I><SUP>2</SUP><SUB>c</SUB>. Here, <I>I</I><SUB>c</SUB> is the critical current. For the range of <I>H</I><SUB>peak</SUB>/<I>H</I><SUB>c</SUB>≤ 3, the <I>g</I>-values of SmBCO CC tape were larger than those of YBCO CC tape. However, for the range of <I>H</I><SUB>peak</SUB>/<I>H</I><SUB>c</SUB> ≥ 3, the <I>g</I>-values of SmBCO CC tape were smaller than those of YBCO CC tape. When <I>H</I><SUB>peak</SUB>/<I>H</I><SUB>c</SUB> = 3, both sample show almost same value of <I>g.</I>However we found qualitatively different <I>J–B</I> hysteretic curves for both samples. We also compared our <I>g</I>-values with other <I>g</I>-values, which were directly measured by energy loss experiments. Our <I>g</I>-values of YBCO CC tapes were basically similar to the Brandt's theoretical values of <I>g</I> in the most range of <I>I</I><SUB>peak</SUB> in our measurements.</P>

Ex situ catalytic upgrading of lignocellulosic biomass components over vanadium contained H-MCM-41 catalysts

Kim, B.S.,Jeong, C.S.,Kim, J.M.,Park, S.B.,Park, S.H.,Jeon, J.K.,Jung, S.C.,Kim, S.C.,Park, Y.K. Elsevier Science Publishers 2016 CATALYSIS TODAY - Vol.265 No.-

<P>H-V-MCM-41 catalysts containing 5, 10, and 30 wt% of vanadium were synthesized and applied to the ex situ catalytic pyrolysis (CP) of three polymeric components of lignocellulosic biomass for the first time. Characterization of the catalysts was performed using N-2 adsorption-desorption, XRD, FT-IR, and NH3-TPD. The results of XRD analysis showed that 5 wt% and 10 wt% H-V-MCM-41 catalysts maintained the mesoporous structure, whereas the mesoporous structure was destroyed in 30 wt% H-V-MCM-41 with considerable amount of small V2O5 crystalline outside the framework. NH3-TPD showed that H-V-MCM-41 has mostly weak acid sites and that 10 wt% H-V-MCM-41 had the largest quantity of acid sites due to framework vanadium. In the case of CP of cellulose using Py-GC/MS, 10 wt% H-V-MCM-41 showed the highest catalytic activity for the production of valuable furanic compounds such as furfural because of the enhanced deoxygenation over the acid sites formed on framework vanadium. In the case of CP of xylan as well, 10 wt% H-V-MCM-41 led to the largest yield of mono-aromatics. The production of acetic acid was also promoted by H-V-MCM-41 catalysts. The CP of lignin over H-V-MCM-41 catalysts promoted substantially the production of important feedstock chemicals for the petrochemical industry: phenolics and mono-aromatics. (C) 2015 Elsevier B.V. All rights reserved.</P>

Site-specific mutagenesis of yeast 2-Cys peroxiredoxin improves heat or oxidative stress tolerance by enhancing its chaperone or peroxidase function

Hong, S. H.,Lee, S. S.,Chung, J. M.,Jung, H. s.,Singh, S.,Mondal, S.,Jang, H. H.,Cho, J. Y.,Bae, H. J.,Chung, B. Y. Springer Science + Business Media 2017 Protoplasma Vol.254 No.1

<P>Yeast peroxiredoxin II (yPrxII) is an antioxidant enzyme that plays a protective role against the damage caused by reactive oxygen species (ROS) in Saccharomyces cerevisiae. This enzyme consists of 196 amino acids containing 2-Cys Prx with highly conserved two active cysteine residues at positions 48 and 171. The yPrxII has dual enzymatic functions as a peroxidase and molecular chaperone. To understand the effect of additional cysteine residues on dual functions of yPrxII, S79C-yPrxII and S109C-yPrxII, the substitution of Ser with Cys residue at 79 and 109 positions, respectively, was generated. S109C-yPrxII and S79C-yPrxII showed 3.7- and 2.7-fold higher chaperone and peroxidase activity, respectively, than the wild type (WT). The improvement in enzyme activity was found to be closely associated with structural changes in proteins. S109C-yPrxII had increased beta-sheet in its secondary structure and formed high-molecular-weight (HMW) as well as low-molecular-weight (LMW) complexes, but S79C-yPrxII formed only LMW complexes. HMW complexes predominantly exhibited a chaperone function, and LMW complexes showed a peroxidase function. In addition, transgenic yeast cells over-expressing Cys-substituted yPrxII showed greater tolerance against heat and oxidative stress compared to WT-yPrxII.</P>

放射菌을 利用한 異種間 原形質體 融合과 그 融合體의 安定性에 관한 硏究(Ⅱ)

閔洪基,金昌珉,孫麗源,韓惠勝,崔英珠,丁大映,韓康玄,李相燮,李欽淑,元奉必 국립보건연구원 1992 국립보건원보 Vol.29 No.2

Induction of bone formation by <i>Escherichia coli</i>‐expressed recombinant human bone morphogenetic protein‐2 using block‐type macroporous biphasic calcium phosphate in orthotopic and ectopic rat models

Park, J‐,C.,So, S‐,S.,Jung, I‐,H.,Yun, J‐,H.,Choi, S‐,H.,Cho, K‐,S.,Kim, C‐,S. Blackwell Publishing Ltd 2011 Journal of periodontal research Vol.46 No.6

<P><I>Park J‐C, So S‐S, Jung I‐H, Yun J‐H, Choi S‐H, Cho K‐S, Kim C‐S. Induction of bone formation by</I> Escherichia coli<I>‐expressed recombinant human bone morphogenetic protein‐2 using block‐type macroporous biphasic calcium phosphate in orthotopic and ectopic rat models. J Periodont Res 2011; 46: 682–690. © 2011 John Wiley & Sons A/S</I></P><P><B>Background and Objective: </B> The potential of the <I>Escherichia coli</I>‐expressed recombinant human bone morphogenetic protein‐2 (ErhBMP‐2) to support new bone formation/maturation using a block‐type of macroporous biphasic calcium phosphate (bMBCP) carrier was evaluated in an orthotopic and ectopic rat model.</P><P><B>Material and Methods: </B> Critical‐size (Φ 8 mm) calvarial defects and subcutaneous pockets in 32 Sprague–Dawley rats received implants of rhBMP‐2 (2.5 μg) in a bMBCP carrier or bMBCP alone (control). Implant sites were evaluated using histological and histometric analysis following 2‐ and 8‐wk healing intervals (eight animals/group/interval).</P><P><B>Results: </B> ErhBMP‐2/bMBCP supported significantly greater bone formation at 2 and 8 wk (10.8% and 25.4%, respectively) than the control at 2 and 8 wk (5.3% and 14.0%, respectively) in calvarial defects (<I>p</I> < 0.01). Bone formation was only observed for the ErhBMP‐2/bMBCP ectopic sites and was significantly greater at 8 wk (7.5%) than at 2 wk (4.5%) (<I>p</I> < 0.01). Appositional and endochondral bone formation was usually associated with a significant increase in fatty marrow at 8 wk. The bMBCP carrier showed no evidence of bioresorption.</P><P><B>Conclusion: </B> ErhBMP‐2/bMBCP induced significant bone formation in both calvarial and ectopic sites. Further study appears to be required to evaluate the relevance of the bMBCP carrier.</P>

Key Features in the Operation of KSTAR

Jong-Gu Kwak,Oh, Y. K.,Kim, K. P.,Kim, S. W.,Hong, S. H.,Chu, Y.,Lee, H. J.,Kim, Y. O.,Kim, J.,Park, S. L.,Hahn, S. H.,Park, M. K.,Kim, H. K.,Bak, J. G.,Bae, Y. S.,Ko, W. H.,Lee, S. G.,Lee, J. H.,Jung IEEE 2012 IEEE transactions on plasma science Vol.40 No.3

<P>The Korea Superconducting Tokamak Advanced Research (KSTAR) device is aimed at advanced tokamak (AT) research. Three years have passed since it achieved its first plasma in 2008. Because it is a superconducting machine and is working toward AT research, it has unique features in terms of the machine engineering and operation. The toroidal field (TF) magnet coils are made of Nb<SUB>3</SUB>Sn, which provide high TFs up to 3.5 T, and have been fully tested. The poloidal field (PF) magnet coils, consisting of both Nb<SUB>3</SUB>Sn and NbTi, which have a maximum current of 25 kA in their design, were tested up to 15 kA. A thermal hydraulic analysis is being conducted for PF magnet coil operation. All plasma-facing components (PFCs) are equipped with water cooled graphite tiles and have the capability of being baked up to 350°C. A startup scenario, which considered both the effect of the ferromagnetic material in the cable in conduit conductor jacket of the magnet coils as well as a nonferromagnetic up-down asymmetry in the cryostat structure, was developed and demonstrated its effectiveness by the last two year's reliable operations. Passive stabilizers and in-vessel control coils (IVCCs) are key components to realize AT operation in KSTAR. The segmented IVCC coils were connected to form circular coils for internal vertical control in 2010, and diverted plasmas with high elongation (κ~1.8, δ>;0.6) were achieved. A neutral beam injection (NBI) system was developed aiming at 2 MW, 300 s per ion source which meets the long-pulse requirement of KSTAR. An NBI ion source with a power of 1.7 MW at 100 kV has been commissioned for 10 s. Finally, ELMy H-modes were successfully produced with 1.3-MW NBI power at a plasma current of 0.6 MA in the 2010 campaign. The first H-mode discharge (#4200) in KSTAR was achieved one year earlier than officially planned and was done at B<SUB>T</SUB> = 2 T with I<SUB>p</SUB> = 0.6 MA in a well-balanced double null configuration after boronization on the PFC. Successful operations in the early days of KSTAR including H-mode experiments revealed the capability of advanced and steady-state operation which is essential for the international thermonuclear experimental reactor (ITER) and future fusion reactors.</P>

Optimization of combined (acid + thermal) pretreatment for fermentative hydrogen production from Laminaria japonica using response surface methodology (RSM)

Jung, K.W.,Kim, D.H.,Kim, H.W.,Shin, H.S. Pergamon Press ; Elsevier Science Ltd 2011 International journal of hydrogen energy Vol.36 No.16

In the present work, a combined (acid + thermal) pretreatment was applied for the enhanced fermentative H<SUB>2</SUB> production (FHP) from Laminaria japonica. Various pretreatment conditions including HCl concentrations, heating temperatures, and reaction times were optimized via response surface methodology (RSM) with a Box-Behnken design (BBD). Through regression analysis, it was found that H<SUB>2</SUB> yield was well fitted by a quadratic polynomial equation (R<SUP>2</SUP> = 0.97), and the HCl concentration was the most significant factor influencing FHP. The desirable pretreatment conditions found were HCl concentration of 4.8%, temperature of 93 <SUP>o</SUP>C, and reaction time of 23 min, under which H<SUB>2</SUB> yield reached to 159.6 mL H<SUB>2</SUB>/g dry cell weight (dcw). The main organic acids produced were acetic and butyric acids that related closely with H<SUB>2</SUB> production. The concentration of hydroxymethylfurfural (HMF), a byproduct formed during the pretreatment process, showed an inverse relationship with H<SUB>2</SUB> yield, indicating that pretreatment conditions for the H<SUB>2</SUB> production from L. japonica were successfully optimized, by increasing the hydrolysis rate of the feedstock and also reducing the formation of HMF.

Effects of CO₂ addition on flame extinction in interacting H₂-air and CO-air premixed flames

Jung, S.W.,Park, J.,Kwon, O.B.,Kim, Y.J.,Keel, S.I.,Yun, J.H.,Lim, I.G. Butterworths [etc.] ; Elsevier Science Ltd 2014 Fuel Vol.136 No.-

The effects of CO<SUB>2</SUB> addition on the downstream interactions of H<SUB>2</SUB>-air and CO-air premixed flames were investigated. Flame stability diagrams mapping the extinction limits for various fuel concentrations as functions of the strain rate were developed for the downstream interactions between H<SUB>2</SUB>-air and CO-air premixed flames with 0-20% CO<SUB>2</SUB> addition. Of particular concern was the impact of the chemical reactions of the additional CO<SUB>2</SUB> on the flame extinction characteristics. The results showed that CO<SUB>2</SUB> addition suppressed the flammable regions appreciably and decreased the critical strain rate, opening up the lean extinction boundary. For highly stretched interacting flames, two flammable island regions on the maps were combined into one when 10% or 20% CO<SUB>2</SUB> was added to either the H<SUB>2</SUB>-air or CO-air premixed mixtures. The chemical reactions of the additional CO<SUB>2</SUB> were significant, especially for high strain rate flames, while the effect of the radiative heat loss of the additional CO<SUB>2</SUB> was minor, even for low strain rate flames. Such chemical reactions were determined by competition between the reaction steps for the consumption and production of HCO and the reverse reaction of CO+OH=CO<SUB>2</SUB>+H with the reaction step of H+O<SUB>2</SUB>→O+OH, an indicator of the overall reaction rate for the H atoms. This resulted in a weakened interacting flame. Such chemical reactions of the additional CO<SUB>2</SUB> were examined in detail to describe the flame characteristics.

H-beam 압연 최종패스에서 소재 후단부의 상·하 압하력 변화에 대한 연구

김성기(S. G. Kim),정현석(H. S. Jung),위창현(C. H. Wee),문홍길(H.G. Moon),서경호(K. H. Seo),변상민(S. M. Byon),이영석(Y. S. Lee) 한국소성·가공학회 2023 한국소성가공학회 학술대회 논문집 Vol.2023 No.5

Emergence of Panton-Valentine leucocidin-positive ST8-methicillin-resistant Staphylococcus aureus (USA300 clone) in Korea causing healthcare-associated and hospital-acquired bacteraemia

Jung, J.,Song, E. H.,Park, S. Y.,Lee, S. R.,Park, S. J.,Sung, H.,Kim, M. N.,Kim, S. H.,Lee, S. O.,Choi, S. H. Springer Science + Business Media 2016 European journal of clinical microbiology & infect Vol.35 No.8

<P>Panton-Valentine leucocidin (PVL)-positive sequence type (ST)8-MRSA-SCCmec IVa (USA300) is the epidemic strain of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) in North America. USA300 is extremely rare in South Korea, and PVL-negative ST72 SCCmec type IVc is the predominant CA-MRSA clone. In a multicentre, prospective cohort study of S. aureus bacteraemia, we identified PVL-positive ST8-MRSA isolates by performing multilocus sequence typing and PCR for PVL. We analyzed the clinical characteristics of patients with PVL-positive ST8-MRSA bacteraemia, and performed SCCmec, spa, and agr typing, PCR for arginine catabolic mobile element (ACME), virulence gene profiling, and pulsed-field gel electrophoresis (PFGE). Among a total of 818 MRSA isolates, we identified ten isolates of PVL-positive ST8-MRSA (USA300) (3 from Hospital D, 4 from Hospital G, and 3 from Hospital A), all of which involved exclusively healthcare-associated (5 isolates) and hospital-acquired bacteraemia (5 isolates). This strain accounted for 8 similar to 10 % of the hospital-acquired MRSA bacteraemia in Hospitals D and G. Bacteraemia of unknown origin was the most common type of infection followed by pneumonia. All the isolates were SCCmec type IVa, spa type t008, and agr group I. Eight of the isolates harboured ACME. In a PFGE analysis, four isolates were identical to the USA300 control strain, five differed by a single band, and the remaining one differed by two bands. All the isolates were pulsed-field type USA300. This is the first report of healthcare-associated and hospital-acquired bacteraemia caused by USA300 in South Korea. USA300 seems to be an emerging hospital clone in this country.</P>