• Title/Summary/Keyword: critical current ($I_c$)

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Sex hormones alter the response of Toll-like receptor 3 to its specific ligand in fallopian tube epithelial cells

  • Zandieh, Zahra;Amjadi, Fatemehsadat;Vakilian, Haghighat;Aflatoonian, Khashayar;Amirchaghmaghi, Elham;Fazeli, Alireza;Aflatoonian, Reza
    • Clinical and Experimental Reproductive Medicine
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    • v.45 no.4
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    • pp.154-162
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    • 2018
  • Objective: The fallopian tubes play a critical role in the early events of fertilization. The rapid innate immune defense is an important part of the fallopian tubes. Toll-like receptor 3 (TLR3), as a part of the innate immune system, plays an important role in detecting viral infections. In this basic and experimental study, the effect of sex hormones on the function of TLR3 in the OE-E6/E7 cell line was investigated. Methods: The functionality of TLR3 in this cell line was evaluated by cytokine measurements (interleukin [IL]-6 and IL-1b) and the effects of sex hormones on TLR3 were tested by an enzyme-linked immunosorbent assay kit. Additionally, TLR3 small interfering RNA (siRNA) and a TLR3 function-blocking antibody were used to confirm our findings. Results: The production of IL-6 significantly increased in the presence of polyinosinic-polycytidylic acid (poly(I:C)) as the TLR3 ligand. Using a TLR3-siRNA-ransfected OE-E6/E7 cell line and function-blocking antibody confirmed that cytokine production was due to TLR3. In addition, 17-${\beta}$ estradiol and progesterone suppressed the production of IL-6 in the presence and absence of poly(I:C). Conclusion: These results imply that sex hormones exerted a suppressive effect on the function of TLR3 in the fallopian tube cell line when different concentrations of sex hormones were present. The current results also suggest that estrogen receptor beta and nuclear progesterone receptor B are likely to mediate the hormonal regulation of TLR3, as these two receptors are the main estrogen and progesterone receptors in OEE6/E7 cell line.

The Effect of Burn-out Temperature and Cooling Rate on the Microstructure and Corrosion Behavior of Dental Casting Gold Alloy (치과용 합금 주조 시의 소환온도와 주조 후 냉각방법이 미세조직과 부식거동에 미치는 영향)

  • Lee, Sang-Hyeok;Ham, Duck-Sun;Kim, Hak-Kwan;Jang, Ju-Woong;Kim, Myung-Ho
    • Journal of Technologic Dentistry
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    • v.22 no.1
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    • pp.69-78
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    • 2000
  • The microstructure and corrosion behavior of commercially dental casting gold alloys were investigated to clarify the effect of burn-out temperature and cooling rate. In the case of water quenching after casting, only the αphase, which is typical dendritic microstructure of golda alloy, was detected. However, the precipitates along the grain boundary were detected only at the slow cooling rate and they increased inversely proportional to the burn-out temperature. This might be due to the time difference which solute atom could diffuse. EPMA and SEM results also demonstrated that the precipitate should be lamellar structure consisted of Ag rich phase(${\alpha}_1$) and Cu rich phase (${\alpha}_2$). In terms of corrosion, the galvanic coupling was formed due to the difference of composition between precipitates and matrix at the slow cooling rate. In the case of water quenching, the critical current density($i_p$) which indicate the degree of corrosion was lowest at $650^{\circ}C$ and below the burnout temperature, $i_p$ increased with it because of the effect of grain boundary segregation. But above the temperature, $i_p$ increased with it. This may be due to the strain field effect by residual thermal stress.

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Synthesis and Structural Properties of YBa2Cu3O7-x Films/ZnO Nanorods on SrTiO3 Substrates

  • Jin, Zhenlan;Park, C.I.;Song, K.J.;Han, S.W.
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.08a
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    • pp.169-169
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    • 2012
  • The high-temperature superconductor YBa2Cu3O7-x (YBCO) have attached attentions because of a high superconducting transition temperature, low surface resistance, high superconducting critical current density (Jc), and superior superconducting capability under magnetic field. Moreover, the Jc of YBCO superconductors can be enhanced by adding impurities to the YBCO films for vortex-pinning. Understanding and controlling pinning centers are key factors to realize high Jc superconductors. We synthesized vertically-aligned ZnO nanorods on SrTiO3 (STO) substrates by catalyst-free metal-organic chemical vapor deposition (MOCVD), and subsequently, deposited YBCO films on the ZnO nanorods/STO templates using pulsed laser deposition (PLD). The various techniques were used to analyze the structural and interfacial properties of the YBCO/ZnO nanorods/STO hybrid structures. SEM, TEM, and XRD measurements demonstrated that YBCO films on ZnO nanorods/STO were well crystallized with the (001) orientation. EXAFS measurements from YBCO/ZnO nanorods/STO at Cu K edge demonstrated that the local structural properties around Cu atoms in YBCO were quite similar to those of YBCO/STO.

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Two-Dimensional Electron Gas (2DEG) at $Ta_2O_5/SrTiO_3$ Heterointerface

  • Joung, Jin Gwan;Yoo, Kwang Soo;Kim, Jin Sang;Baek, Seung-Hyub
    • Proceedings of the Korean Vacuum Society Conference
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    • 2013.02a
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    • pp.161-161
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    • 2013
  • Two-dimensional electron gas (2DEG) has been investigated at the heterointerface between two insulating dielectric perovskite oxides, $LaAlO_3$ (LAO)/$SrTiO_3$ (STO). Properties of the 2DEG have attracted an enormous interest in condensed matter physics due to multifunctional properties such as the coexistence of ferromagnetism and superconductivity, as well as the high electron mobility. Here, we have grown $Ta_2O_5$ thin films using pulsed laser deposition on $SrTiO_3$ substrate to investigate the electric properties of the $Ta_2O_5$/STO heterointerface. Our research reveal that the non-polar $Ta_2O_5$/$TiO_2$ heterointerface favors the formation of 2DEG similar to that at the LAO/STO heterointerface. The metallic behavior was found in this heterointerface with the current about $10{\sim}100{\mu}A$ at 5 V by using conventional I-V measurements, when the $Ta_20_5$ film thickness reaches over critical thickness, $d_c{\simeq}2uc$. The finding that electrons was localized at $Ta_2O_5$/STO heterointerface have attracted to be strong and new candidate for nanoscale oxide device applications.

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Fabrication and Characterization of Step-Edge Josephson Junctions on R-plane Al$_2O_3$ Substrates (R-면 사파이어 기판 위에 제작된 계단형 모서리 조셉슨 접합의 특성)

  • Lim, Hae-Ryong;Kim, In-Seon;Kim, Dong-Ho;Park, Yong-Ki;Park, Jong-Chul
    • 한국초전도학회:학술대회논문집
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    • v.9
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    • pp.147-151
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    • 1999
  • YBCO step-edge Josephson junction were fabricated on sapphire substrates. The steps were formed on R-plane sapphire substrates by using Ar ion milling with PR masks. The step angle was controlled in the wide range from 25$^{\circ}$ to 50$^{\circ}$ by adjusting both the Ar ion incident angle and the photoresist mask rotation angle relative to the incident Ar ion beam. CeO$_2$ buffer layer and in-situ YBa$_2Cu_3O_{7-{\delta}}$ (YBCO) thin films was deposited on the stepped R-plane sapphire substrates by pulsed laser deposition method. The YBCO film thickness was varied to obtain the ratio of film thickness to step height in the range from 0.5 to 1. The step edge junction exhibited RSJ-like behaviors with I$_cR_n$ product of 100 ${\sim}$ 300 ${\mu}$V, critical current density of 10$^3$ ${\sim}$ 10$^5$ A/ cm$^2$ at 77 K.

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Study on the shape design of field coil in HTS generator considering stress condition

  • Jo, Young-Sik;Lee, Ju-Min;Hong, Jung-Pyo;Lee, Ju;Sohn, Myung-Hwan;Kwon, Young-Kil;Ryu, Kang-Sik
    • 한국초전도학회:학술대회논문집
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    • v.10
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    • pp.257-261
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    • 2000
  • The value of I$_c$(critical current) in HTS (High Temperature Superconductor) tape has a great influence on B${\bot}$(vertical field). Therefore, in shape design of field coil for the HTSG(High Temperature Superconducting Generator), a method to reduce the B${\bot}$ should be considered in order to maintain the stability and substantial improvement on the performance. On the basis of the magnetic field analysis, this paper deals with various field coil shape according to the iron plate to obtain small B${\bot}$ by using Biot-Savart's law, image method and 2D FEA(2 Dimensional Finite Element Analysis) considering the stress condition of HTS. Moreover, the analysis is verified by comparison with experimental results. And also this paper presents the advanced model by using 3D FEA, in which flux density at armature is calculated in 5kVA class HTSG.

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Meter-long coated conductor by R2R PVD methods on RABiTS template

  • Ko, Rock-Kil;Kim, Ho-Sup;Ha, Hong-Soo;Chung, Jun-Ki;Yang, Joo-Saing;Park, Yu-Mi;Shi, Dong-Qi;Song, Kyu-Jeong;Park, Chan;Yoo, Sang-Im;Moon, Seung-Hyun;Kim, Young-Cheol
    • Progress in Superconductivity and Cryogenics
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    • v.6 no.4
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    • pp.13-16
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    • 2004
  • Three film deposition systems (pulsed laser deposition, sputtering, and evaporation) equipped with reel-to-reel metal tape moving apparatus were installed and used to make meter-long coated conductor. Buffer architecture of $CeO_2/YSZ/Y_2O_3$ was deposited on Ni alloy using sputtering, evaporation, and PLD. YBCO superconducting layer was continuously deposited on buffered metal tape by PLD. End-to-end critical current ($I_c$) of 107 A at 77 K, self-field has been achieved in 1 em-wide tape (thickness 0.6∼1.0${\mu}{\textrm}{m}$, tape moving speed 54∼72 cm/hr) over 1 meter length.

Characteristic Study According to the Shape of Field in the Air-cored HTS Synchronous Generator (공심형 HTS 동기발전기의 계자 형상 변화에 따른 특성연구)

  • Jo, Young-Sik;Ahn, Ho-Jin;Hong, Jung-Pyo;Lee, Ju;Kwon, Young-Kil;Ryu, Kang-Sik
    • Proceedings of the KIEE Conference
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    • 2000.07b
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    • pp.849-851
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    • 2000
  • The value of $I_c$(critical current) in HTS (High Temperature Superconductor) tape has a great influence on $B{\bot}$ (vertical field). Therefore, in shape design of field coil for the HTSG(High Temperature Superconducting Generator), a method to reduce the $B{\bot}$ should be considered in order to maintain the stability and substantial improvement on the performance. On the basis of the magnetic field analysis, this paper deals with various field coil shape to obtain small $B{\bot}$ by using Biot-Savart's law and image method. Moreover the analysis is verified by comparison with experimental results. And also this paper presents the advanced model by using 3D FEM(3 Dimensional Finite Element Method), in which flux density at armature is calculated in 5kVA class HTSG.

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A Study on Stability of Ag sheathed Bi-2229 tape and Cylindrical Stacking Conductor for HTS Cable (고온초전도 케이블용 은시스 Bi-2223 테이프 및 적층 도체의 안정성연구)

  • Lee, B.S.;Kim, Y.S.;Jang, H.M.;Back, S.M.;Kim, S.H.
    • Proceedings of the KIEE Conference
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    • 2000.07c
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    • pp.1554-1556
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    • 2000
  • Normal zone propagation(NZP) characteristics were investigated on Ag sheathed multi filamentary Bi-2223 tape and cylindrical stacking conductor. The critical current($I_c$) of Ag sheathed Bi-2223 tape and cylindrical stacking conductor were 12 A, 63 A at 77 K, 0 T. Normal zone propagation(NZP) experiments with tape were conducted with refrigerator in temperature from 45 K to 77 K, 0 T. Cylindrical stacking conductor was molding with epoxy and experiments were conducted with adiabatic condition in $LN_2$. NZP velocities of tape with two condition of DC and AC were almost same at each temperature. Temperature ($T_1$) of tape with distance of 0.5 cm from heater was strongly climbed up to 95K and slowly decreased. NZP velocities of cylindrical stacking conductor were 1.9-2.4 cm/sec in $LN_2$.

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Effect of tensile strain on $I_{c}$ degradation characteristics in Bi-2223 superconducting tapes under bending (Bi-2223 초전도테이프 임계전류의 굽힘하에서 인장변형률 특성)

  • 신형섭;오상수;하동우
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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    • 2003.10a
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    • pp.134-138
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    • 2003
  • The influences of mixed mode of bending-tension on the Ic degradation and their interaction on the strain effect were evaluated in this study. A test fixture which applies a mixed deformation mode of bending-tension to HTS tapes has been newly devised. When the strain induced in the tape due to the mixed deformation mode was expressed as a total tensile strain, the irreversible strain to the critical current degradation of Bi-2223 tapes increased when compared with the case of simple bending mode, and the value at both ends were larger than that at the central region of the bend part. The Ic degradation behavior at the region exceeding the irreversible strain showed quiet a rapid drop of the Ic when compared with the simple bending cases. As the applied bending strain increased namely as the diameter of mandrel adopted decreased, the apparent irreversible strain of Bi-2223 tapes increased However, the increment decreased as the mandrel diameter decreased. As a result, it could be found that the tension to be applied to the Bi-2223 tapes during cabling of HTS tapes should be smaller, as the mandrel diameter becomes smaller.

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