Progress in the development of heating systems towards long pulse operation for KSTAR

Kwak, J.G.,Bae, Y.D.,Chang, D.H.,Chang, D.S.,Hong, B.G.,Hwang, C.K.,In, S.R.,Jeong, S.H.,Jin, J.T.,Jung, K.S.,Kim, B.R.,Kim, J.,Kim, S.K.,Kim, T.S.,Lee, D.W.,Lee, K.W.,Oh, B.H.,Seo, C.S.,Seo, M.S.,Yoo International Atomic Energy Agency 2007 Nuclear fusion Vol.47 No.5

<P>Construction of the Korea superconducting tokamak advanced research (KSTAR) tokamak is in its final phase. For the long-pulse KSTAR discharges, the ion cyclotron range of frequencies (ICRF) and neutral beam injection (NBI) heating systems are expected to play important roles through a selective heating of ions and electrons, control of the plasma pressure and current profiles, a core fuelling and beam diagnostics for the KSTAR. In addition, the ICRF system is expected to be used for possible discharge cleaning and assisting in the tokamak startup. In this paper, the recent progress in the development of the ICRF and the NBI heating systems is described. The four-strap ICRF antenna has been successfully tested for a voltage up to 41 kV for a pulse length of 300 s (to 46 kV for 20 s) in a test chamber. A prototype KSTAR NBI system has been developed. At present, the system has successfully produced a 1 MW beam power for 200 s and a 3.5 MW output beam power for 4 s.</P>

Limiting Concentrate during Growing Period Affect Performance and Gene Expression of Hepatic Gluconeogenic Enzymes and Visfatin in Korean Native Beef Calves

Chang, S.S.,Lohakare, J.D.,Singh, N.K.,Kwon, E.G.,Nejad, J.G.,Sung, K.I.,Hong, S.K. Asian Australasian Association of Animal Productio 2013 Animal Bioscience Vol.26 No.2

This study elucidated the effects of limited concentrate feeding on growth, plasma profile, and gene expression of gluconeogenic enzymes and visfatin in the liver of Hanwoo beef calves. The purpose of this study was to test that reducing the amount of concentrate would partially be compensated by increasing the intake of forage and by altering the metabolic status. The study utilized 20 Korean native beef calves (Hanwoo; 60 to 70 d of age) divided into two groups of 10 calves each for 158 d. Control group calves received the amount of concentrate as per the established Korean feeding standards for Hanwoo, whereas calves in the restricted group only received half the amount of concentrate as per standard requirements. Good quality forage (Timothy hay) was available for ad libitum consumption to both groups. Since calves were with their dam until 4 months of age in breeding pens before weaning, the intake of milk before weaning was not recorded, however, the concentrate and forage intakes were recorded daily. Body weights (BW) were recorded at start and on 10 d interval. Blood samples were collected at start and at 50 d interval. On the final day of the experiment, liver biopsies were collected from all animals in each group. The BW was not different between the groups at all times, but tended to be higher (p = 0.061) only at final BW in control than restricted group. Total BW gain in the control group was 116.2 kg as opposed to 84.1 kg in restricted group that led to average BW gain of 736 g/d and 532 g/d in respective groups, and the differences were significant (p<0.01). As planned, the calves in the control group had higher concentrate and lower forage intake than the restricted group. The plasma variables like total protein and urea were higher (p<0.05) in control than restricted group. The mRNA expressions for the gluconeogenic enzymes such as cytosolic phosphoenol pyruvate carboxykinase (EC 4.1.1.32) and pyruvate carboxylase (EC 6.4.1.1), and visfatin measured by quantitative real-time PCR in liver biopsies showed higher expression (p<0.05) in restricted group than control. Overall, restricting concentrate severely reduced the growth intensity and affected few plasma indices, and gene expression in liver was increased indicating that restricting concentrate in the feeding schemes during early growth for beef calves is not advocated.

RF Interference Analysis for KOMPSAT-II Spacecraft

Lim, S.B.,Kim, D.Y.,Chang, Y.K. 통신위성우주산업연구회 2001 Joint Conference on Satellite Communications Vol.2001 No.-

In general, LEO satellite uses S-band communication link for the whole satellite management, whereas the satellite payload frequently implements X-band and/or Ku-band transmitter for payload data transmission. The transmission system should have out-band rejection filter (protection circuit) to prevent any interference with the satellite receiver, so that the receiver can be normally operated. It is usually implemented in the transmitter itself but the vendor of a transmitter could not take it into account whole out of band frequency because a variety of individual satellites utilize different RF communication systems. The KOMPSAT-II, which is an earth observation satellite, is being developed by Korea Aerospace Research Institute and Korean industries. It has S-band communication system for the bus and X-band transmission system for payload data. In addition, L-band GPS Receiver is being incorporated to achieve the KOMPSAT-II mission goal. Unfortunately, the KOMPSAT-2 payload system does not have external out-band rejection~ filter nor transmitter for S-band and L-band protection. The transmitter only has band rejection filter for TDRSS. In addition, it has high gain directional antenna whose directional beam has to pass over the S-band antenna. In this paper, the analysis method is described to calculate the interference effects of the S-band spurious noise power on X-band transmitting system to S-band receiver. The S-band antenna is positioned very closely to the X-band Antenna by I .2m. We will also introduce general simple RF interference analysis method applicable to a traditional system, including advantage and disadvantages. The X-band transmitting system is often required to add the specified filter to suppress the S-band spurious signal for the safety of the receiver performance. The analysis result shows that the performance of S-band receiver is satisfied with no implementation of the specified filter.

유전자 알고리즘을 이용한 InGaP/GaAs HBT 소신호 등가회로 파라미터 추출

장덕성(D.S. Chang),문종섭(J.S. Moon),박철순(C.S. Park),윤경식(K.S. Yoon) 한국지능시스템학회 2001 한국지능시스템학회논문지 Vol.11 No.6

에미터 크기가 2×10 μm²인 InGaP/GaAs 이종접합 바이폴라 트랜지스터의 T자 모양으로 연결된 등가회로 요소를 추출하기 위하여, 경계 구간 설정이 개선된 유전자 알고리즘을 채택하였다. 이 소신호 모델 파라미터를 유전자 알고리즘을 사용하여, 다양한 순방향 바이어스에서 측정한 S-파라미터들로부터 추출하였다. 추출된 값들은 물리적인 의미와 일관성을 보여준다. 모델 S-파라미터는 측정 S-파라미터와 2GHz- 26.5GHz의 주파수 범위에서 잘 일치한다. The present approach based on the genetic algorithm with improved selections of bounds was adopted to extract a bridged T equivalent circuit elements of a 2×10 μm² InGaP/GaAs HBT. The small-signal model parameters were extracted using the genetic algorithm from S-parameters measured at different frequencies under multiple forward-active biases, which demonstrate physically meaningful values and consistency. The agreement between the measured and modeled S-parameters is excellent over the frequency range of 2 to 26.5GHz.

Designing the substrate specificity of d-hydantoinase using a rational approach

Lee, S.C.,Chang, Y.,Shin, D.M.,Han, J.,Seo, M.H.,Fazelinia, H.,Maranas, C.D.,Kim, H.S. IPC Science and Technology Press ; Elsevier Scienc 2009 Enzyme and microbial technology Vol.44 No.3

Enzymes that exhibit superior catalytic activity, stability and substrate specificity are highly desirable for industrial applications. These goals prompted the designed substrate specificity of Bacillus stearothermophilusd-hydantoinase toward the target substrate hydroxyphenylhydantoin (HPH). Positions crucial to substrate specificity were selected using structural and mechanistic information on the structural loops at the active site. The size and hydrophobicity of the involved amino acids were rationally changed, and the substrate specificities of the designed d-Hyd mutants were investigated. As a result, M63I/F159S exhibited about 200-fold higher specificity for HPH than the wild-type enzyme. Systematic mutational analysis and computational modeling also supported the rationale used in the design.

1987년 한국에서 발생한 렙토스피라병의 혈청역학적 조사

이증훈,박영수,이우곤,김석용,정선식,우준희,박성광,박경희,송영욱,김선영,기정일,최두혁,강성귀,김주완,최강원,김우열,최명식,최인학,장우현,윤성열 대한감염학회 1988 감염 Vol.20 No.3

Human leptospirosis was an unfamiliar disease in Korea until 1984 that outbreak of leptospirosis occurred among farmers and soldiers after field works for harvesting rice. During that time, Lee and Jo confirmed the first Korean cases of leptospirosis by serological test, isolation of causative agent and autopy findings. Afterward several outbreaks occurred also during autumn especially after flood in every years and some characterisitcs of leptospirosis in Korea such as clinical manifestations, serotypes and seroepidemiological features has been revealed by many investigators. Because of the major mode of transmission between rodents and human is by direct contact with leptospiral urine of rodents or contaminated soil by the urine, leptospirosis in Korea has been primarily a disease of person in occupations heavily exposed to contaminated soil or infected urine such as farmer, army and etc. Therefore it seems that leptospirosis is one of the main communicable diseases to be controlled urgently in Korea, for an agricultural people account for almost half of total Korean people. For clarifying the seroepidemiological patterns of human leptospirosis in Korea by sex, month region and main reacting serovars of L. interrogans among acute febrile disease occurred in 1987, 1,773 patient's sers with acute febrile episodes were tested by microagglutination test using 19 representative strains of leptospiral serogroup as antigen. All of those sera were collected from 10 collaborative clinics located in Kyunggi, Kangwon, Chungbuk, Chungnam, Chonbuk, Chonnam province and Seoul. The results wee summerized as follows. 1) Among 1,773 sera of patients with acute febrile episodes, 219 (12.4%) were seropositive to L. interrogans, 487(27.5%) to R. tsutsugamushi, 241(13.6%) to R.typhi and 160(90.0%) to Hantaan virus. 2) Among seropositives to L.interrogans, the male outnumbered the female, 65% and 35%. 3) For age distribution, 26.9% of seropositives to L.interrogans were fifties, 19.6% were forties, 9.1% were sixties, 5.9% were thirties and 4.1% were twenties. 4) Eighty three percent of seropositives had occurred between September and October in 1987 with a peak in September. 5) Main leptospiral serovars reactive to patient's sera were Icterohaemorrhagiae(54.3%), Canicola(31.0%), CH-48(13.2%), Tarassovi(0.9%)and Cynopteri(0.5%). 6) For regional distribution, 65.8% of seropositives to L.interrogans were residents from Chonbuk, 12.3% were Chonnam, 7.3% were Chungnam, 5.5% were Kyunggi and 1.4% were Kangwon.

Temperature and air pollution affected tree ring δ¹³C and water-use efficiency of pine and oak trees under rising CO₂ in a humid temperate forest

Kwak, J.H.,Lim, S.S.,Lee, K.S.,Viet, H.D.,Matsushima, M.,Lee, K.H.,Jung, K.,Kim, H.Y.,Lee, S.M.,Chang, S.X.,Choi, W.J. Elsevier 2016 Chemical geology Vol.420 No.-

<P>To better predict forest productivity under rising atmospheric CO2 concentration ([CO2]), it is critical to understand how intrinsic water-use efficiency (WUEi) and its relationship with tree growth are affected by the concomitant changes in environmental conditions such as precipitation, temperature, and air pollution that either enhance or undermine any potential CO2 fertilization effect. We investigated changes in delta C-13 and WUEi in annual rings and basal area increment (BAI) of Pinus densiflora (from 1968 to 2007) and Quercus variabilis (from 1970 to 2007) trees in relation to precipitation, temperature, and air pollution in a humid temperate forest. The WUEi of P. densiflora increased by 39.9%, whereas that of Q. variabilis did not change over time in the study period. The WUEi was not affected by precipitation for both species but increased (P < 0.001) with temperature for P. densiflora and with SO2 emissions for both species. Multiple regression models suggested that the effect of [CO2] on tree growth was much higher than temperature; however, for the period (1998 to 2007) when SO2 emissions data were available, SO2 emission was the driver of changes in BAI and WUEi, and temperature effects became stronger than [CO2]. Overall, BAI and WUEi were positively (P < 0.001) correlated for P. densiflora, but not for Q. variabilis. We conclude that temperature and air pollution rather than precipitation were key determinants of WUEi at the study site and that the two species had contrasting responses to environmental changes. (C) 2015 Elsevier B.V. All rights reserved.</P>

Peroxiredoxin II promotes hepatic tumorigenesis through cooperation with Ras/Forkhead box M1 signaling pathway

Park, Y-H,Kim, S-U,Kwon, T-H,Kim, J-M,Song, I-S,Shin, H-J,Lee, B-K,Bang, D-H,Lee, S-J,Lee, D-S,Chang, K-T,Kim, B-Y,Yu, D-Y Macmillan Publishers Limited 2016 Oncogene Vol.35 No.27

<P>The current study was carried out to define the involvement of Peroxiredoxin (Prx) II in progression of hepatocellular carcinoma (HCC) and the underlying molecular mechanism(s). Expression and function of Prx II in HCC was determined using H-ras(G12V)-transformed HCC cells (H-ras(G12V)-HCC cells) and the tumor livers from H-ras(G12V)-transgenic (Tg) mice and HCC patients. Prx II was upregulated in H-ras(G12V)-HCC cells and H-ras(G12V)-Tg mouse tumor livers, the expression pattern of which highly similar to that of forkhead Box M1 (FoxM1). Moreover, either knockdown of FoxM1 or site-directed mutagenesis of FoxM1-binding site of Prx II promoter significantly reduced Prx II levels in H-ras(G12V)-HCC cells, indicating FoxM1 as a direct transcription factor of Prx II in HCC. Interestingly, the null mutation of Prx II markedly decreased the number and size of tumors in H-ras(G12V)-Tg livers. Consistent with this, knockdown of Prx II in H-ras(G12V)-HCC cells reduced the expression of cyclin D1, cell proliferation, anchorage-independent growth and tumor formation in athymic nude mice, whereas overexpression of Prx II increased or aggravated the tumor phenotypes. Importantly, the expression of Prx II was correlated with that of FoxM1 in HCC patients. The activation of extracellular signal-related kinase (ERK) pathway and the expression of FoxM1 and cyclin D1 were highly dependent on Prx II in H-ras(G12V)-HCC cells and H-ras(G12V)-Tg livers. Prx II is FoxM1-dependently- expressed antioxidant in HCC and function as an enhancer of Ras(G12V) oncogenic potential in hepatic tumorigenesis through activation of ERK/FoxM1/cyclin D1 cascade.</P>

Protein Profile in Corpus Luteum during Pregnancy in Korean Native Cows

Chung, H.J.,Kim, K.W.,Han, D.W.,Lee, H.C.,Yang, B.C.,Chung, H.K.,Shim, M.R.,Choi, M.S.,Jo, E.B.,Jo, Y.M.,Oh, M.Y.,Jo, S.J.,Hong, S.K.,Park, J.K.,Chang, W.K. Asian Australasian Association of Animal Productio 2012 Animal Bioscience Vol.25 No.11

Steroidogenesis requires coordination of the anabolic and catabolic pathways of lipid metabolism, but the profile of proteins associated with progesterone synthesis in cyclic and pregnant corpus luteum (CL) is not well-known in cattle. In Experiment 1, plasma progesterone level was monitored in cyclic cows (n = 5) and pregnant cows (n = 6; until d-90). A significant decline in the plasma progesterone level occurred at d-19 of cyclic cows. Progesterone level in abbatoir-derived luteal tissues was also determined at d 1 to 5, 6 to 13 and 14 to 20 of cyclic cows, and d-60 and -90 of pregnant cows (n = 5 each). Progesterone level in d-60 CL was not different from those in d 6 to 13 CL and d-90 CL, although the difference between d 6 to 13 and d-90 was significant. In Experiment 2, protein expression pattern in CL at d-90 (n = 4) was compared with that in CL of cyclic cows at d 6 to 13 (n = 5). Significant changes in the level of protein expression were detected in 32 protein spots by two-dimensional polyacrylamide gel electrophoresis (2-DE), and 23 of them were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Six proteins were found only in pregnant CL, while the other 17 proteins were found only in cyclic CL. Among the above 6 proteins, vimentin which is involved in the regulation of post-implantation development was included. Thus, the protein expression pattern in CL was disorientated from cyclic luteal phase to mid pregnancy, and alterations in specific CL protein expression may contribute to the maintenance of pregnancy in Korean native cows.

Simulation of Rough Rice Drying by Natural Air(Ⅰ)

Chang, D. I.,Chung, D. S.,Pfost, H. B.,Calderwood, D. L. 충남대학교 농업과학연구소 1983 農業技術硏究報告 Vol.10 No.1

Simulation model of natural air grain drying was discussed and modified to predict the changes of grain moisture content and dry matter loss of rough rice drying. The modified simulation model was then validated using actual test data. A series of simulated drying tests using official weather data for 15 years from Beaumont, Texas, was taken to make minimum airflow rate and maximum bed depth of rough rice drying by natural air, under different conditions of initial moisture content of rough rice, airflow rate and harvest date.