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Quench Detection Based on Voltage Measurement for the KSTAR Superconducting Coils
Yong Chu,Yonekawa, H.,Kim, Y.O.,Park, K.R.,Hyun Jung Lee,Park, M.K.,Park, Y.M.,Lee, S.J.,Ha, T.H.,Oh, Y.K.,Bak, J.S. IEEE 2009 IEEE transactions on applied superconductivity Vol.19 No.3
<P>To protect the KSTAR (Korea Superconducting Tokamak Advanced Research) superconducting coils against a quench, the quench detection system based on voltage measurement was fabricated. It used a detect/dump scheme which detects the presence of non-recovering normal zones and activates a dump circuit that transfers most of the stored energy into a dump resistor. Even though it is desirable to discharge the coil energy as fast as possible after quench detection, a time delay between the quench detection and the complete dump circuit actuation will be necessary in order that the quench voltage is to be distinguished from various noises. The quench threshold voltage and the delay time should be set before operation for quench voltage detection so that the maximum hot-spot temperature could be limited to 150 K. This paper describes the hardware techniques to prevent the malfunction of the quench detection due to voltage noises arising from the KSTAR operating scenarios. During the first operation of the KSTAR machine, the inductive voltages and other voltage noises were measured and effectively compensated below voltage thresholds. A quench did not occur and the quench detection system was well operated without any false activation.</P>
현웅조(Ung-Jo Hyun),원용재(Yong-Jae Won),정응기(Eung-Gi Jeong),안억근(Eok-Keun Ahn),이정희(Jeong-Heui Lee),정국현(Kuk-Hyun Jung),박향미(Hyang-Mi Park),전용희(Yong-Hee Jeon),곽지은(Jieun Kwak),성낙식(Nak-Sig Sung),김정천(Jeong-Cheon K 한국육종학회 2021 한국육종학회지 Vol.53 No.2
Alchanmi’, a japonica rice variety, was developed from a cross between ‘Junam’ and ‘Chilbo’ by a rice breeding team at the NationalInstitute of Crop Science and Icheon, Agricultural Technology Center in 2018. The heading date of ‘Alchanmi’ was August 10 in the middleplain area-two days later than that of ‘Hwaseong’. ‘Alchanmi’ had a culm length of 69 cm, 16 cm shorter than that of ‘Hwaseong’, and 103spikelets per panicle. The viviparous germination rate of ‘Alchanmi’ was 24.4%. It showed resistance to blast, bacterial blight (K1, K2, K3race), and stripe virus, but was susceptible to the K3a race of bacterial blight, dwarf and black streak dwarf viruses, and plant hoppers. Themilled rice of this variety exhibited a translucent and medium short grain shape. The cooked rice grains of ‘Alchanmi’ had an excellent palatabilityindex (0.7) and showed lower amylose content (18.6%) than that of ‘Hwaseong’. The grain milling characteristics of ‘Alchanmi’ were betterthan those of ‘Hwaseong’, especially the head rice milling recovery ratio and head rice ratio (96.2%). ‘Alchanmi’ showed 5.83 MT/ha of milledrice productivity at 6 sites under ordinary cultivation (Registration No. 8132).
치과용 갈륨합금의 조성변화가 부식 및 기계적특성에 미치는 영향
박영준,이용렬,이도재,Norling, Berry K,Rawls, H Ralph 대한치과기재학회 2001 대한치과재료학회지 Vol.28 No.2
This study was performed to evaluate the effects of compositional variations of dental gallium alloys on their corrosion and mechanical behaviors. 60Ag-28Sn-12Cu wt% (ST group) was prepare by atomization. ST-Pd and ST-Pt groups were prepared by substituting part of tin (Sn) with Pd (2 wt%) and Pt (0.05 wt%), respectively. Low-and high-copper amalgam alloys (LCA and HCA) were also prepared by atomization method for comparison. Alloy powders of each group were mixed with liquid gallium alloy that was composed of 61.98Ga-24.99In-12.98Sn-0.05Bi wt%. Specimens were made according to ADA specification no. 1. Corrosion behavior was evaluated by potentiodynamic anodic polarization test together with X-ray diffractometry (XRD), and scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS). 24 hour-compressive strengths and dimensional changes were measured. Following results were obtained. ST-Pd group showed most anodic behavior with the corrosion potential (E□) of-707 mV (vs. SCE), which is a significant shift in the noble direction from the -883 mV(vs.SCE) of the ST group (p<0.05). Among the specimens of St-Pd group, one specimen even had an E□ of -580 mV showing pronounced improvement in corrosion resistance. LCA group showed the worst corrosion resistance, having E□ of -896 mV. Set specimens had multi-phase microstructures consisting of Ag9In4, CuGa₂, □-Sn, Ag□₂Ga₂□, AG₄Sn and Cu3Sn, and all the groups showed similar XRD patterns. Ag9In4 was the main reaction matrix phase showing strongest XRD peak. CuGa2 phase surrounded the unreacted powder particles. A mixture of light Ag9In4 phase and a dark gray Ga42.3-Cu17.1-Ag16.8-Bi0.2 wt% solid solution appeared in the intergranular layer. ST-Pd group required the shortest mixing time. The intensity of the Ag4Sn peak of unreacted powder was lower and peak intensity of Ag□Ga₂□ phase, which is more corrosion resistant, was higher when compared to that of ST group. Sn(Cu)-Cl corrosion products having various morphologies were formed on corroded specimen surfaces. ST-Pd group had lesser deposition of corrosion product compared to other groups. LCA group specimens corroded more than HCA group specimens. 27-hour ST-Pd group showed highest value compared to those of other groups (p<0.05). HCA group showed higher compressive strength compared to that of LCA group. 24-hour setting expansions were ST-Pd*****(0.24%)<<LCH(0.43%)<ST-Pt(0.51%) <ST(0.56%)<<HCA(1.33). ST-Pd group showed significantly lower setting expansion (p<0.014). HCA group having 28 wt% Cu in alloy powder showed 1.33% setting expansion value which is significantly higher than those of other groups (p<0.01). In summary, substituting 2 wt% palladium for 2 wt% tin in the alloy powder improved the corrosion resistance and compressive strength, and reduced the degree of setting expansion. High-copper content induced excessive setting expansion. This finding indicates that there is still room for further improvement of the corrosion resistance and mechanical properties of dental gallium alloys through composition modification. With furher research, there is still a possibility for gallium alloy to become a successful substitute for dental amalgam.
이병국,황규윤,장봉기,김용배,리갑수,안현철,김화성,이성수,안규동,박종범 순천향대학교 산업의학연구소 1999 순천향산업의학 Vol.5 No.1
The inhibition of δ-aminolevulinic acid dehydratase (ALAD) in the heme synthetic pathway results in increased protophoryphyrin (ZPP) and δ-aminolevulinic acid (ALA) and is responsible for some of toxicological effects of lead. This enzyme is coded by the ALAD gene containing 2 co-dominant alleles. The polymorphisms of ALAD gene may be related to differential effects of lead on ZPP and ALA, ALAD genotype was measured in 975 Korean male lead workers, of whom 897 were homozygous for ALAD1 (ALAD 1-1 genotype) and 96 were heterozygous for ALAD2 (ALAD 1-2 genotype). Blood lead in subjects with ALAD1 was significantly higher than those with ALAD2 (p = 0.01). No difference between ALAD genotypes was found for age, exposure duration, ZPP, ALA, hemoglobin, hematocrit, body mass index, tobacco and alcohol use. After adjustment for possible confounders, ALA and ZPP became significantly elevated in ALAD1 subjects (p = 0.004 and 0.055, respectively). This result suggests that ALAD1 subjects may be more susceptible to the hematotoxicologic effects of lead than ALAD2 subjects.