Tropane Spirohydantoin들의 합성 및 구조분석

정대일,이도훈,송주현,이용균,최순규,박유미,한정태 동아대학교 환경문제연구소 2006 硏究報告 Vol.28 No.1

The tropane ring system is an important substructure in a number of natural products and synthetic compounds of biological and medicinal importance. As a result of the significance of the tropane ring system, the purpose of this study is the synthesis of anticonvulsant compounds of new s tructure anticipated anticonvulsant activity. After we first synthesized the various N-substituted nortropinone derivatives, we prepared new nortropane alkaloids and nortropinone derivatives. Substantially, we tried several experiments to optimize reaction condition. The tropane spirohydantoins 17, 18, 19, 20, 21 were respectively synthesized by the treatment of corresponding N-substituted nortropinone with potassium cyanide and ammonium carbonate.

Arc-Magnetron 복합 코팅 공정에 의한 (TiAl)N 박막 합성에 관한 연구

한전건,윤주선,한준희 대한금속재료학회(대한금속학회) 2000 대한금속·재료학회지 Vol.38 No.3

(TiAl)N films deposited by cathodic arc process employing two separate targets of Al and Ti have lots of macro-particles on the surface. The macro-particles were found out to be generated mainly from Al cathode of low melting temperature. In the previous study, TiN films deposited with external magnetic field showed remarkable reduction of surface droplet. For the (TiAl)N coatings, however, the efficiency of Al droplet removal was not so much as TiN films. A new coating concept combining magnetron sputtering and arc evaporation for improved coating properties was made in this study. (TiAl)N and Al-gradient (TiAl)N coatings were deposited by arc-magnetron hybrid process and content of Al in the films was changed by power density of Al magnetron sputtering source. This hybrid process allowed compositionally gradient (TiAl)N coatings to be deposited with low macro-particles and excellent adhesion. It is noted that Al-gradient (TiAl)N coating showed micro hardness of 3,000 ㎏/㎟ and good adhesion of HF2 grade. The present study introduces the hybrid process parameters involved. The formation behavior of (TiAl)N and Al-gradient (TiAl)N coatings were investigated by SEM, EDX AES and XRD.

Formation of the internal transport barrier in KSTAR

Chung, J.,Kim, H.S.,Jeon, Y.M.,Kim, J.,Choi, M.J.,Ko, J.,Lee, K.D.,Lee, H.H.,Yi, S.,Kwon, J.M.,Hahn, S.-H.,Ko, W.H.,Lee, J.H.,Yoon, S.W. International Atomic Energy Agency 2018 Nuclear fusion Vol.58 No.1

<P>One of key objectives of tokamak experiments is the exploration of enhanced confinement regimes, and the access of the internal transport barrier (ITB) formation is dealt with an important physics issue in the most of major tokamaks. Also, the advanced tokamak scenario with ITB is expected to lead to a continuous reactor with high fusion power density. From that point of view, the formation of the ITB in KSTAR which is designed for long pulse operation capability is very important although its heating and current drive systems are not fully equipped yet. We have therefore assumed that an early injection of the full NBI power (∼5.5 MW) during the current ramp-up would give a chance to form an internal barrier if the plasma could stay in the L-mode. To avoid the H-mode transition, we have produced inboard limited plasmas with detaching from the both upper and lower divertors. Using this approach, an ITB formation during L-mode has been observed which shows improved core confinement. Ion and electron temperature profiles show the barrier clearly in the temperature, and it was sustained for about 7 s in the dedicated experiment. This is the first stationary ITB observed in a full superconducting tokamak. This operation scenario with the ITB could be an alternative way to achieve a high performance regime in KSTAR, and the length of the ITB discharge could be extended even longer. In this paper, we present the formation of the ITB using measured and simulated characteristic profiles.</P>

Electric Probe Measurements at Edge Region During H‐Mode Discharges in KSTAR

Bak, J.G.,Oh, Y.S.,Kim, H.S.,Hahn, S.H.,Yoon, S.W.,Jeon, Y.M.,Xiao, W.W.,Ko, W.H.,Kim, W.C.,Kwak, J.G.,Woo, H.J.,Chung, K.S.,the KSTAR project team, WILEY‐VCH Verlag 2013 Contributions to plasma physics Vol.53 No.1

<P><B>Abstract</B></P><P>Electrical probe measurements are carried out at the scrape‐off‐layer (SOL) and divertor regions in order to investigate the characteristics of edge plasmas during H‐mode discharges in the Korea Superconducting Tokamak Advanced Research (KSTAR) device. Radial profiles of plasma parameters such as electron temperature T<SUB><I>e</I></SUB>, plasma density n<SUB><I>e</I></SUB>, and parallel flow velocity v<I><SUB>‖</SUB></I> are measured by using a fast reciprocating Langmuir probe assembly (FRLPA) at the SOL region. From the FRLPA measurements, it is found that the decay length of temperature λ<I><SUB>Te</SUB></I> and that of density λ<I><SUB>ne</SUB></I> are 2 <I>∼</I> 4 cm and 1 <I>∼</I> 3 cm, respectively. The magnitude of v<I><SUB>‖</SUB></I> near the last closed flux surface (LCFS) is 4 <I>∼</I> 15 km/s. The radial flux due to edge turbulence at the SOL region is investigated by using spectra analysis on electrostatic fluctuation levels such as ion saturation current Ĩ<I><SUB>is</SUB></I> and floating potential <TEX>$ \tilde{\rm V}_f$</TEX> obtained from the FRLPA measurement. The value of the flux is estimated as <I>∼</I> 10<SUP>20</SUP> particle m<SUP>−2</SUP> s <SUP>−1</SUP> near the LCFS. The poloidal distribution of the ion saturation current density j<I><SUB>is</SUB></I> is measured by fixed edge Langmuir probe array (ELPA) at the divertor region, and it is found that the positions of strike points from the ELPA measurement agree well with those reconstructed from the EFIT result using magnetic diagnostic data. From the spectrum analysis on the ELPA measurements at the divertor region during edge localized modes (ELMs) control in the H‐mode discharges, it is observed that the magnitude of <TEX>$ \tilde{\rm j}_{is}$</TEX>(<I>ω</I>) near strike point decreases when the ELMs are suppressed or mitigated (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)</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>

Negative Regulation of JAK2 by H3K9 Methyltransferase G9a in Leukemia

Son, H.-J.,Kim, J.-Y.,Hahn, Y.,Seo, S.-B. American Society for Microbiology 2012 Molecular and cellular biology Vol.32 No.18

Exendin-4 induction of cyclin D1 expression in INS-1 beta-cells: involvement of cAMP-responsive element.

Kim, M-J,Kang, J-H,Park, Y G,Ryu, G R,Ko, S H,Jeong, I-K,Koh, K-H,Rhie, D-J,Yoon, S H,Hahn, S J,Kim, M-S,Jo, Y-H Journal of Endocrinology, Ltd. [etc.] 2006 The Journal of endocrinology Vol.188 No.3

<P>Glucagon-like peptide-1 (GLP-1) and its analog exendin-4 (EX) have been considered as a growth factor implicated in pancreatic islet mass increase and beta-cell proliferation. This study aimed to investigate the effect of EX on cyclin D1 expression, a key regulator of the cell cycle, in the pancreatic beta-cell line INS-1. We demonstrated that EX significantly increased cyclin D1 mRNA and subsequently its protein levels. Although EX induced phosphorylation of Raf-1 and extracellular-signal-regulated kinase (ERK), both PD98059 and exogenous ERK1 had no effect on the cyclin D1 induction by EX. Instead, the cAMP-elevating agent forskolin induced cyclin D1 expression remarkably and this response was inhibited by pretreatment with H-89, a protein kinase A (PKA) inhibitor. Promoter analyses revealed that the cAMP-responsive element (CRE) site (at position -48; 5'-TAACGTCA-3') of cyclin D1 gene was required for both basal and EX-induced activation of the cyclin D1 promoter, which was confirmed by site-directed mutagenesis study. For EX to activate the cyclin D1 promoter effectively, CRE-binding protein (CREB) should be phosphorylated and bound to the putative CRE site, according to the results of electrophoretic mobility shift and chromatin immunoprecipitation assays. Lastly, a transfection assay employing constitutively active or dominant-negative CREB expression plasmids clearly demonstrated that CREB was largely involved in both basal and EX-induced cyclin D1 promoter activities. Taken together, EX-induced cyclin D1 expression is largely dependent on the cAMP/PKA signaling pathway, and EX increases the level of phosphorylated CREB and more potently trans-activates cyclin D1 gene through binding of the CREB to the putative CRE site, implicating a potential mechanism underlying beta-cell proliferation by EX.</P>

RF 마그네트론 스퍼터링법에 의한 a-축 배향 $YBa_2Cu_3O_{7-\delta}$박막의 제조

이재준,김영환,신진,이경희,최상삼,한택상,Lee, J.J.,Kim, Y.H.,Shin, J.,Lee, K.H.,Choi, S.S.,Hahn, T.S. 한국재료학회 1994 한국재료학회지 Vol.4 No.4

a-측으로 배향된 $YBa_2Cu_3O_{7-\delta}$ 고온 초전도 박막을 $LaAIO_{3}$(100)단결정 기판에 이중 타게트 off-axis rf마그네트론 스퍼터링법으로 증착하였다. 박막은 기판온도(Ts)$590^{\circ}C$와 $680^{\circ}C$사이에서 단일공정으로 증착하는 one-step방법과, $590^{\circ}C$의 저온에서 a-축으로 배향된 YBCO박막(두께-30nm)을 면저 만들어 틀로 작용시킨 후 그 틀위에 나머지 부분을 기판온도를 승온하면서 증착하는 방법인 two-step방법 등 두 가지 방법을 사용하여 증착시켰다. one-step방법에서는 $T_s$가 증가함에 따라 감소하였으며, ($00 \ell$)피크는 증가하였다. Two-step방법으로 증착한 박막은 증착속도가 감소함에 따라 (h00)피크가 우세하게 나타났다. 박막의 미세구조는 a-축, c- 축 배향성이 혼재하여 핀홀과 같은 결함들이 생성되었다. 모든 경우 $T_s$가 감소함에 따라 a-축 배향성은 우세하였으나 전기적 특성은 저하되었고, 긴 전이온도 폭을 가졌다. A-axis oriened YBCO thin flims were grown on $LaAIO_{3}$ single crystal substrate by off-axis rf magnetron sputtering method. We used two kinds of process to get a-axis oriented fi1ms;one-step process and two-step process. In one-step process, films are grown in single step in which substrate temperature( $T_s$) is in the range of $590^{\circ}C$ to $680^{\circ}C$. On the other hand, in two step process a-axis oriented thin film templates i f about 30nm thickness is deposited at low temperature first, and subsequently films are grown at elevated temperature to the final thickness of about 100nm. In the case of one step process($T_s$ ~)$600^{\circ}C$), prefered a-axis orientation is dominant and Cu-rich phases segregate at the surface. Segregations decrease and ($00 \ell$) peaks increase upon increasing $T_s$. The films prepared by two step method appeared to have strong(h00) peaks as the deposition rate increased. Microstructure shows pin holes resulted from mixed phases of a-axis and c-axis oriented films. In both cases of one step and two step process, as TS decreases, prepared films show stronger a-axis orientation. However electrical properties of the films are depressed with lower $T_c$ and wider $\Delta T$ as $T_s$ decreases.

Equilibrium and global MHD stability study of KSTAR high beta plasmas under passive and active mode control

Katsuro-Hopkins, O.,Sabbagh, S.A.,Bialek, J.M.,Park, H.K.,Bak, J.G.,Chung, J.,Hahn, S.H.,Kim, J.Y.,Kwon, M.,Lee, S.G.,Yoon, S.W.,You, K.-I.,Glasser, A.H.,Lao, L.L. International Atomic Energy Agency 2010 Nuclear fusion Vol.50 No.2

<P>The Korea Superconducting Tokamak Advanced Research, KSTAR, is designed to operate a steady-state, high beta plasma while retaining global magnetohydrodynamic (MHD) stability to establish the scientific and technological basis of an economically attractive fusion reactor. An equilibrium model is established for stability analysis of KSTAR. Reconstructions were performed for the experimental start-up scenario and experimental first plasma operation using the EFIT code. The VALEN code was used to determine the vacuum vessel current distribution. Theoretical high beta equilibria spanning the expected operational range are computed for various profiles including generic L-mode and DIII-D experimental H-mode pressure profiles. Ideal MHD stability calculations of toroidal mode number of unity using the DCON code shows a factor of 2 improvement in the wall-stabilized plasma beta limit at moderate to low plasma internal inductance. The planned stabilization system in KSTAR comprises passive stabilizing plates and actively cooled in-vessel control coils (IVCCs) designed for non-axisymmetric field error correction and stabilization of slow timescale MHD modes including resistive wall modes (RWMs). VALEN analysis using standard proportional gain shows that active stabilization near the ideal wall limit can be reached with feedback using the midplane segment of the IVCC. The RMS power required for control using both white noise and noise taken from NSTX active stabilization experiments is computed for beta near the ideal wall limit. Advanced state-space control algorithms yield a factor of 2 power reduction assuming white noise while remaining robust with respect to variations in plasma beta.</P>

A search for 0νββ decay of ¹²⁴Sn with tin-loaded liquid scintillator

KIMS Collaboration,Hwang, M.J.,Kwon, Y.J.,Kim, H.J.,Kwak, J.W.,Kim, S.C.,Kim, S.K.,Kim, T.Y.,Kim, S.Y.,Lee, H.S.,Lee, M.J.,Myung, S.S.,Kim, Y.D.,Lee, J.I.,Kang, W.G.,Hahn, I.S.,Lee, M.H. North-Holland ; Elsevier Science Ltd 2009 Astroparticle physics Vol.31 No.6

<P>A search for the neutrinoless double-beta decay of Sn-124 was carried out using the tin-loaded liquid scintillator for an active source-detector technique. Tin (32.6%) in weight was successfully loaded into the liquid scintillator, and light output was as high as 57% of the unloaded liquid scintillator. A tin-loaded liquid scintillator with 1.1 l volume was installed at the 700 m underground laboratory in YangYang. and data were taken for 5285 h. No evidence for the O nu beta beta decay was found and a lower limit on the Sn-124 half-life was obtained to be 2.0 x 10(19) year with 90% C.L The new limit represents a significant improvement with respect to those previously available for Sn-124. (C) 2009 Elsevier B.V. All rights reserved.</P>