• Title/Summary/Keyword: $T_{\omega}$

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Study on the miniaturized HTS antenna using H-type resonators for satellite communication systems. ('H'형태 공진기를 이용한 축소화된 위성통신 기지국용 고온초전도 안테나에 관한 연구)

  • Chung, D.C.;Lim, S.H.;Choi, H.S.;Hwang, J.S.;Han, B.S.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.07a
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    • pp.559-562
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    • 2004
  • The $high-T_c$ Superconducting(HTS) antenna which consists of "H" type resonator has the benefits for the miniaturization of antenna in comparison with the microstrip antenna of the similar dimension. To fabricate the "H" type antenna HTS $YBa_2Cu_3O_{7-x}$(YBCO) thin films were deposited on MgO substrates using rf-magnetron sputtering. Standard etching processes were performed for the patterning of the "H" type antenna. For comparison between normal conducting antennas and superconducting antennas, the gold antennas with the same dimension were also fabricated. An aperture coupling was used for impedance matching between $50\Omega$ feed line and HTS radiating patch. The diverse experimental results were reported in terms of the resonant frequency, the return loss and the characteristics impedance. The "H" type superconducting antenna showed the performance of 1.36 in SWR, 24 % in efficiency, and 14.6 dB in the return loss superior to the normal conducting counterpart.

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HALL EFFECT AND RESISTIVITY OF AMORPHOUS $Fe_{83-x}Zr_{7}B_{10}Nb_{x}$ ALLOYS

  • Lee, Soo-Hyung;Yu, Seong-Cho;Xu, Jun-Hau;Rao, K.V.;Noh, Tae-Hwan;Kang, Il-Koo;Rhie, Kungwon
    • Journal of the Korean Magnetics Society
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    • v.5 no.5
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    • pp.772-777
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    • 1995
  • The effect of small addition of Nb on the electrical resistivity and Hall coefficient of the amorphous $Fe_{83}Zr_{7}B_{10}$ alloy and annealed ones below the crystallization temperature were investigated, which has been considered to be suitable for high frequency core material. At room temperature, their resistivities $\rho$ and the spontaneous Hall coefficients $R_{s}$ are $~1.6\;{\mu}{\Omega}m$ and $~3{\times}10^{-8}m^{3}/As$, respectively. $R_{s}$ and $\rho$ are decreased with increasing temperature from 100 K to room temperature. Side-jump effect was adopted to analyze the effect of the small variation of concentration and annealing. The quantity of $R_{s}/{\rho}^{2}$ at room temperature, which is directly related to the electronic structure of the mother alloy, remained almost a constant except as quenched one as it can be predicted from the side-jump effect. We suggested the temperature dependence of $R_{s}/{\rho}^{2}$ can be compared to Ms{T}.

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Structural and Electrical Properties of SrRuO3 thin Film Grown on SrTiO3 (110) Substrate

  • Kwon, O-Ung;Kwon, Namic;Lee, B.W.;Jung, C.U.
    • Journal of Magnetics
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    • v.18 no.1
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    • pp.39-42
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    • 2013
  • We studied the structural and electrical properties of $SrRuO_3$ thin films grown on $SrTiO_3$ (110) substrate. High resolution X-ray diffraction measurement of the grown film showed 1) very sharp peaks for $SrRuO_3$ film with a very narrow rocking curve with FWHM = $0.045^{\circ}$ and 2) coherent growth behavior having the same in-plane lattice constants of the film as those of the substrate. The resisitivity data showed good metallic behavior; ${\rho}$ = 63(205) ${\mu}{\Omega}{\cdot}cm$ at 5 (300) K with a residual resistivity ratio of ~3. The observed kink at ${\rho}(T)$ showed that the ferromagnetic transition temperature was ~10 K higher than that of $SrRuO_3$ thin film grown on $SrTiO_3$ (001) substrate. The observed rather lower RRR value could be partially due to a very small amount of Ru vacancy generally observed in $SrRuO_3$ thin films grown by PLD method and is evident in the larger unit-cell volume compared to that of stoichiometric thin film.

Trends in Canadian Dietary Supplements Enhanced with Female Hormones Required in Response to the COVID-19 Pandemic (코로나19 (COVID-19) 팬데믹에 대응하여 요구되는 여성호르몬이 강화된 캐나다산 식이 보충제의 동향)

  • Shim, Youn Young;Reaney, Martin J.T.;Lee, Hak Sung;Kim, Hye-Jin
    • Journal of the FoodService Safety
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    • v.3 no.1
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    • pp.1-7
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    • 2022
  • As one of the post-COVID-19 response strategies, representative processed products derived from the natural plant material flaxseed and a dietary supplement fortified with female hormones (estrogens) were developed in Canada, an eco-friendly country was introduced. These products were: 1) flaxseed oil to help maintain cognitive and immune function, 2) Lignan50, a substance with effects similar to estrogen, a female hormone, 3) XanFlax, a thickener for confectionery/baking and egg substitute, 4) MediFlax, a constipation reliever, 5) SesaFlax, which has a fragrance similar to sesame, 6) Linusorb, which is effective for its pharmaceutical anti-inflammatory/anti-oxidation and anti-aging properties, and 7) LinuLyte, a water/electrolyte supplement containing high dietary fiber. It is expected that these dietary products will help maintain and promote health as part of a response to the COVID-19 pandemic.

A Study on Wired LogiC for Type Unit for PLC Output Driving (PLC 출력 구동을 위한 Wired Logic for Type Unit에 관한 연구)

  • 위성동;김태성
    • Journal of the Korean Institute of Telematics and Electronics T
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    • v.36T no.1
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    • pp.51-57
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    • 1999
  • This thesis is written about the Wired Logic Type Unit in developing equipment that the load is driven, that the interface unit connect with 1 Scan time to PO30 of operated PLC output contact with that a sensing signal of Temperature Sensor RSD Pt $100\Omega$ let generate the relay output of temperature controller and input the PLC. The PLC Test Kit in country that the PLC to be programmed at the PLC education place is able to drive the load, is done to do a education of PLC on status that interface process between PLC and load are disregarded. As Developing Kit for supplement this point, when the relay output of temperature controller to use Pt 100 of temperature sensor as mentioned on the former among every kinds of sensor feed back to the input of the PLC, as the equipment to act with real time system that the output contact of PLC operated to insert the WLTIJ among PC, PLC and the load, it can understand and see very easy the main principle of PLC use. The structure of WLTU to be a interface unit of load separated as to the point of contact and noncontact, sensor, indicating lamp and A contact and B contact that is belong to driving part, and a motor is belong to loading part.

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Capacitively Loaded Loop Antenna Fed with Metamaterial Balun (Metamaterial 발룬으로 급전된 Capacitively Loaded 루프 안테나)

  • Jung, Youn-Kwon;Lee, Bom-Son
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.20 no.10
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    • pp.1084-1090
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    • 2009
  • This paper presents a balun consisting of a T-junction, a Right/Left Handed Transmission line(RLH-TL), and a conventional Right Handed(RH) line. It is assumed that the RLH-TL consists of N unit-cells. We provide closed-form solutions and design a very compact wideband(80 %) balun using CPW lines based on the obtained solutions. Then, we propose a capacitively loaded loop antenna designed for a uniform current distribution. The antenna resistance of the proposed antenna at resonance is about 204 ohms. The length of the unit cell is about $\lambda/12$(total length: $1\;\lambda$). The magnetic field generated from the proposed antenna is stronger than that of the conventional one by as much as 20 dB. We used a coplanar strip line(CPS) to combine the loop antenna and balun. The proposed antenna may be used as a near field UHF RFID reader antenna.

Characteristics of Partial Discharge Under HVDC in SF6 Gas (SF6 가스 중 직류 고전압 하에서 부분방전 특성)

  • Kim, Min-Su;Kim, Sun-Jae;Jeong, Gi-Woo;Jo, Hyang-Eun;Kil, Gyung-Suk
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.27 no.4
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    • pp.238-243
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    • 2014
  • This paper dealt with the measurement and analysis of partial discharge (PD) under high voltage direct current (HVDC) in SF6 gas. Electrode systems such as a protrusion on conductor (POC), a protrusion on enclosure (POE), a crack on epoxy plate and a free particle (FP) were fabricated to simulate the insulation defects. The analysis system was designed with a Time-Frequency (T-F) map algorithm programed based on LabVIEW. This can arrange the acquired PD pulses into frequency and time domain. A HVDC power source is composed of a transformer (220 V/50 kV), a diode (100 kV) and a capacitor (50 kV, 0.5 ${\mu}F$). The gap between the electrodes is 3 mm, and the $SF_6$ gas was set at 5 bar. PD pulses were detected by a 50 ${\Omega}$ non-inductive resistor. In the analysis, PD pulses were distributed below 0.5 MHz and 20 ns ~ 35 ns for the POC, 0.7 MHz ~ 1.7 MHz, below 0.6 MHz and 10 ns ~ 40 ns and 60 ns ~125 ns for the POE, below 0.1 MHz and 135 ns ~ 215 ns for the crack, and below 1.6 MHz and 250 ns for the FP.

Endothelium-Dependent Vasorelaxation Effects of Rubus Coreanus extract on Rabbit Carotid Artery (복분자(覆盆子)의 내피세포의존성 혈관이완효과)

  • Chin, Jun Ho;Park, Sun Young
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.27 no.4
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    • pp.437-445
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    • 2013
  • This study was investigated to evaluate the vasorelaxant effect of Rubus coreanus(RC) extract on contracted rabbit carotid artery and its mechanism. To study the effect of RC extract on contracted rabbit carotid arterial strips, arterial strips with intact or damaged endothelium were used for experiment using organ bath. The pre-contracted arterial strips with norepinephrine(NE) or potassium chloride(KCl) was treated with various concentrations of an extract of RC(0.01, 0.03, 0.1, 0.3 and 1.0 $mg/m{\ell}$). To determine the mechanisms of RC-induced vasorelaxant, RC extract was infused into contracted arterial rings which had been pretreated by indomethacin(IM), tetraethylammonium chloride(TEA), $N{\omega}$-nitro-L-arginine (L-NNA), methylene blue(MB). And calcium chloride(Ca) 1 mM was infused into precontracted arterial ring induced by NE or KCl after treatment of RC extract in $Ca^{2+}$-free krebs solution. Cytotoxic activity of RC extract on human umbilical vein endothelial cell(HUVEC) was measured by MTT assay, and nitric oxide(NO) prodution was measured by Griess reagent. RC extract revealed significant relaxation on NE-induced arterial contraction, but didn't relax on KCl-induced arterial contraction. RC extract also had an effective relaxation to the intact endothelium arterial ring, but not the damaged endothelium arterial ring. Treatment of IM, TEA, L-NNA, MB reduced the relaxation of RC extract. Pretreatment of RC extract inhibited the contraction by influx of extracellular $Ca^{2+}$ in contracted arterial ring induced by NE, but it didn't work the contraction by influx of extracellular $Ca^{2+}$ in contracted arterial ring induced by KCl in $Ca^{2+}$-free krebs solution. RC extract increased nitric oxide production on HUVEC. This study indicated that the relaxation effect of RC extract on contracted rabbit carotid artery is related with NO-cGMP pathway, EDHF, prostacyclin.

A Study on the Improvement on the Target Structure in a Magnetron Sputtering Apparatus (마그네트론 스퍼터링 장치의 타겟구조 개선에 관한 연구)

  • Bae, Chang-Hwan;Lee, Ju-Hee;Han, Chang-Suk
    • Journal of the Korean Society for Heat Treatment
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    • v.23 no.1
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    • pp.23-28
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    • 2010
  • The cylindrical magnetron sputtering has not been widely used, although this system is useful for only certain types of applications such as fiber coatings. This paper presents electrode configurations which improved the complicacy of the target assembly by using the positive voltage power supply. It is a modified type which has a target constructed with a large cylindrical part, a conical part and a small cylindrical part. When positive voltage was applied to an anode, a stable glow discharge was established and a high deposition rate was obtained. The substrate bias current was monitored to estimate the effect of ion bombardment. As a result, it was found that the substrate current was large. With cylindrical and conical cathode magnetron sputter deposition on the surface of the substrate to prevent re-sputtering, ion impact because it can increase the effectiveness with excellent ductility and adhesion of Ti film deposition can be obtained. We board at the front end of the ground resistance of $5\;k{\Omega}$ attached to the substrate potential can be controlled easily, and Ti film deposition with excellent adhesion can be obtained. Microstructure and morphology of Ti films deposited on pure Cu wires were investigated by scanning electron microscopy in relation to preparation conditions. High level ion bombardment was found to be effective in obtaining a good adhesion for Cu wire coatings.

Electrophysiological and Morphological Classification of Inhibitory Interneurons in Layer II/III of the Rat Visual Cortex

  • Rhie, Duck-Joo;Kang, Ho-Young;Ryu, Gyeong-Ryul;Kim, Myung-Jun;Yoon, Shin-Hee;Hahn, Sang-June;Min, Do-Sik;Jo, Yang-Hyeok;Kim, Myung-Suk
    • The Korean Journal of Physiology and Pharmacology
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    • v.7 no.6
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    • pp.317-323
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    • 2003
  • Interneuron diversity is one of the key factors to hinder understanding the mechanism of cortical neural network functions even with their important roles. We characterized inhibitory interneurons in layer II/III of the rat primary visual cortex, using patch-clamp recording and confocal reconstruction, and classified inhibitory interneurons into fast spiking (FS), late spiking (LS), burst spiking (BS), and regular spiking non-pyramidal (RSNP) neurons according to their electrophysiological characteristics. Global parameters to identify inhibitory interneurons were resting membrane potential (>-70 mV) and action potential (AP) width (<0.9 msec at half amplitude). FS could be differentiated from LS, based on smaller amplitude of the AP (<∼50 mV) and shorter peak-to-trough time (P-T time) of the afterhyperpolarization (<4 msec). In addition to the shorter AP width, RSNP had the higher input resistance (>200 $M{Omega}$) and the shorter P-T time (<20 msec) than those of regular spiking pyramidal neurons. Confocal reconstruction of recorded cells revealed characteristic morphology of each subtype of inhibitory interneurons. Thus, our results provide at least four subtypes of inhibitory interneurons in layer II/III of the rat primary visual cortex and a classification scheme of inhibitory interneurons.