• Progress in Superconductivity and Cryogenics
• /
• v.23 no.4
• /
• pp.19-24
• /
• 2021

The low normal zone propagation velocity (NZPV) of high-temperature superconducting (HTS) tape leads to a quench protection problem in HTS magnet applications. To overcome this limitation, various studies were conducted on HTS coils without turn-to-turn insulation (NI coils) that can achieve self-protection. On the other hand, NI coils have some disadvantages such as slow charging and discharging time. Previously, the HTS coils with turn-to-turn insulation (INS coils) were operated in power supply (PS) driven mode, which requires physical contact with the external PS at room-temperature, not in persistent current mode. When a quench occurs in INS coils, the low NZPV delays quench detection and protection, thereby damaging the coils. However, the rotary HTS flux pump supplies the DC voltage to the superconducting circuit with INS coils in a non-contact manner, which causes the INS coils to operate in a persistent current mode, while enabling quench protection. In this paper, a new protection characteristic of HTS coils is investigated with INS coils charging through the rotary HTS flux pump. To experimentally verify the quench protection characteristic of the INS coil, we investigated the current magnitude of the superconducting circuit through a quench, which was intentionally generated by thermal disturbances in the INS coil under charging or steady state. Our results confirmed the protection characteristic of INS coils using a rotary HTS flux pump.

• Proceedings of the KIEE Conference
• /
• 2006.07b
• /
• pp.741-742
• /
• 2006

This paper deals with an efficient superconducting joint method between 2G high superconducting(HTS) wire, YBCO coated conductor(CC). Recently CC is one of the most promising superconducting wire due to high n-value and critical current independency from external magnetic field. It is expected to be used many superconducting application such as fault current limiter, persistent current system and cable etc. In most HTS applications, superconducting magnet is used, and it is necessary to joint between superconducting wire to fabricate superconducting magnet system. A CC tape used in this research consists of copper stabilizer, silver layer, YBCO layer, buffer and substrate. Direct joint using soldering method was inefficient due to resistance of copper, then copper lamination is removed by chemical etching method to reduce resistance between CC tapes. Jointed tapes were fabricated and tested. Transport current through jointed area and induced voltage were measured to characterize the I-V curve. Resistance between CC wire using chemical etching was compared with resistance of direct jointed tapes using soldering method in this paper.

• Clinical and Experimental Pediatrics
• /
• v.51 no.10
• /
• pp.1096-1101
• /
• 2008

Purpose : Patients with chronic granulomatous disease (CGD) have genetic mutations in a component of the NADPH oxidase enzyme that is necessary for the generation of the superoxide anion. The profound defect in innate immunity is reflected by the patients susceptibility to catalase-positive bacteria and fungi. In addition, CGD patients display signs of persistent inflammation, which is not associated only with deficient superoxide anion production. The aim of this study was to elucidate the cytokine responses in CGD patients after $TNF-{\alpha}$ stimulation. Methods : Heparinized blood samples were collected from 8 CGD patients and 10 healthy volunteers. Monocytes ($1{\times}10^6cell/well$) isolated by the magnet cell isolation system were incubated with a constant amount of $TNF-{\alpha}$ (10 ng/mL) at $37^{\circ}C$ for 6 h. Incubated cells were harvested at 60-min intervals for IL-8 and IL-10 mRNA analysis, and the supernatant was collected at the same intervals to determine IL-8 and IL-10 expression. Monocytes from healthy volunteers were also incubated with antioxidants followed by $TNF-{\alpha}$ stimulation for IL-8 and IL-10 expression. Results : In CGD patients, a high expression of IL-8 together with a significantly higher IL-10 expression than in the healthy controls was seen after $TNF-{\alpha}$ stimulation. Moreover, normal monocytes treated with antioxidants exhibited increased IL-8 responses. Conclusion : The absence of phagocyte-derived reactive oxidants in CGD might be associated with a dysregulated production of pro- and antiinflammatory cytokines. Additional research related to reactive oxidants is needed to clarify the role of cytokines in CGD patients.