• Title/Summary/Keyword: J-V characteristics

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A Swing Characteristics and Application Condition of the V type Suspension String Set (V련 현수애자장치의 횡진특성과 실선로 적용)

  • Sohn H.K.;Lee H.K.;Keum E.Y.;Min B.W.;Choi J.S.;Choi I.H.
    • Proceedings of the KIEE Conference
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    • summer
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    • pp.627-629
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    • 2004
  • V type suspension string sets prevent instabilities from swing motion by the horizontal angle and by wind pressure. These installation conditions are controled mainly 3 items - normal swing angle by horizontal angle of line, unusual swing angle by strong wind, minimum vertical loads. We calculated and analysed that factors for the 765kV transmission line condition. And we were tested swing characteristics of V-string sets in real size test situation. So, we find to installation condition for the V type suspension string sets. This results will be used to design of V type suspension string set and to decision of the installation condition.

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The Characteristics of $\lambda$ Vibration-Mode Type Piezoelectric Transformer ($\lambda$ 진동모드형 압전 변압기의 특성)

  • Jeong, S.H.;Lee, J.S.;Hong, J.K.;Chai, H.I.;Yoon, M.S.;Lim, K.J.
    • Proceedings of the KIEE Conference
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    • 1999.11d
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    • pp.981-983
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    • 1999
  • In this paper, the electrical characteristics of $\lambda$ vibration-mode piezoelectric transformer for applying to CCFL driving inverter was investigated. Piezoelectric transformer was made of PZT - PMN - 0.5wt% $Nb_{2}O_{5}$ composition. As a results of the electrical characteristics of piezoelectric transformer, when applied voltage was $35[V_{rms}]$ in $100[k{\Omega}]$ load resistance, output voltage was about $710[V_{rms}]$ and output power was more than 2[W]. As output power increased, step-up ratio and temperature was very stable until output power was 2.5[W]. Also, Efficiency was maximum in $70[k{\Omega}]$ load resistance, and about 89[%]. Also, when CCFL was used as load, the maintaining voltage was $700[V_{rms}]$ and the luminescence was $2000[cd/m^2]$ in applying $25[V_{rms}]$ to piezoelectric transformer. Conclusively, piezoelectric transformer fabricated in this paper can be applied to piezoelectric inverter for CCFL driving.

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Flashover Characteristics of Damaged Insulator Strings for Live-line works in 765kV T/L (765kv 송전선로 활선작업을 위한 불량애자 발생 유형별 전기적 섬락특성 분석)

  • Lee, H.K.;Shon, H.K.;Park, M.Y.;Park, I.P.;Kim, H.J.
    • Proceedings of the KIEE Conference
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    • 2005.05b
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    • pp.31-34
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    • 2005
  • The 765kV transmission line will be maintained by live-line works for efficient operation, In order to maintain the 765kV transmission lines safely by live-line works, lineman have to know flashover characteristics of the insulator strings with damaged insulators. This paper suggests flashover characteristics of the 765kV insulator strings from experimental test results directly.

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345/154 kV Transmission Line model choice and calculation using TMLC (TMLC용 345, 154kV 송전선로 모델 작성 및 계산)

  • Choi, H.K.;Moon, Y.H.;Yoon, J.Y.;Choo, J.B.;Yun, Y.B.;Kim, Y.H.
    • Proceedings of the KIEE Conference
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    • 2001.07a
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    • pp.336-339
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    • 2001
  • Transmission line data are very important for studying loadflow. Short circuit data(positive sequence, zero sequence) of 345kV and 154kV line were calulated and compared with KEPCO's line characteristics data. This Paper presents method of verification and complement of line data in PSS/E loadflow data using TMLC (Transmission Line Characteritics) program.

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Change of electrical properties of XLPE with electirical-tree degradation (XLPE의 전기트리 열화에 따른 전기적특성의 변화)

  • Kang, D.S.;Ryoo, H.S.;Sun, J.H.;Choi, S.D.;Lee, H.J.
    • Proceedings of the KIEE Conference
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    • 1999.07e
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    • pp.2136-2138
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    • 1999
  • In this study, we describe the change of electrical properties of XLPE with electrical-tree degradation. XLPE insulation was used as specimen which was cut off from 22.9kV XLPE insulated cable and made in a type of block. The applying voltages are 8kV, 10kV, 12kV and frequency is 60Hz Ogra needles having tip radius of 10$\mu\textrm{m}$ were inserted in blocks. PD quantity and $tan{\delta}$ and DC current were measured from inception of tree to breakdown and their characteristics were analyzed.

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High Voltage Ti/4H-SiC Schottky Rectifiers (고전압 Ti/4H-SiC 쇼트키 장벽 다이오드 제작 및 특성분석)

  • Kim, C.K.;Yang, S.J.;Lee, J.H.;Noh, I.H.;Cho, N.I.;Kim, N.K.;Kim, E.D.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.07b
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    • pp.834-838
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    • 2002
  • In this paper, we have fabricated 4H-SiC schottky diodes utilizing a metal-oxide overlap structure for electric filed termination. The barrier height and Ideality factor were measured by current-voltage, capacitance-voltage characteristics. Schottky barrier height(SBH) were 1.41ev for Ni and 1.35eV for Pt, 1.52eV for Pt/Ti at room temperature and Pt/Ti Schottky diode exhibited Ideality factor was 1.06 to 1.4 in the range of $25^{\circ}C{\sim}200^{\circ}C$. To improve the reverse bias characteristics, an edge termination technique is employed for Pt/Ti/4H-SiC Schottky rectifiers and the device show excellent characteristics with higher blocking voltage up to 780V compared with unterminated devices.

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Thermoluminescent Characteristics of Newly Developed LiF:Mg,Cu,Na,Si TL Detectors

  • Lee J. I.;Kim J. L.;Chang S. Y.
    • Nuclear Engineering and Technology
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    • v.36 no.1
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    • pp.47-52
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    • 2004
  • Recently, a new sintered pellet-type LiF:Mg,Cu,Na,Si TL detector which has a high sensitivity and good reusability, named KLT-300(KAERI LiF:Mg,Cu,Na,Si TL detector), was developed by the variation of the dopants concentrations and the parameters of the preparation procedure at KAERI (Korea Atomic Energy Research Institute). In this study, the thermoluminescent characteristics of the newly developed TL detectors were investigated. The sensitivity of the TL detector was compared with that of the TLD-100 by light integration. The dose linearity of the detector was tested from $10^{-6}$ Gy up to 30 Gy. The dose response was very linear up to 10 Gy and a sublinear response was observed at higher doses. The energy response of the detector was studied for photon energies from 20 keV to 662 keV. The result shows that a maximum response of 1.004 at 53 keV and a minimum response of 0.825 at 20 keV were observed. The reproducibility study for the TL detector was also carried out. The coefficients of variation for each detector separately did not exceed 0.016, and for all the 10 detectors collectively was 0.0054. Lower limit of detection for the detector was investigated at 70 nGy by the Harshaw 4500 TLD Reader and the residual signal of the TL detector was found to be $0.57\%$.

Optical characteristics of p-type ZnO epilayers doped with Sb by metalorganic chemical vapor deposition

  • Kwon, B.J.;Cho, Y.H.;Choi, Y.S.;Park, S.J.
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.02a
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    • pp.122-122
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    • 2010
  • ZnO is a widely investigated material for the blue and ultraviolet solid-state emitters and detectors. It has been promoted due to a wide-band gap semiconductor which has large exciton binding energy of 60 meV, chemical stability and low radiation damage. However, there are many problems to be solved for the growth of p-type ZnO for practical device applications. Many researchers have made an efforts to achieve p-type conductivity using group-V element of N, P, As, and Sb. In this letter, we have studied the optical characteristics of the antimony-doped ZnO (ZnO:Sb) thin films by means of photoluminescence (PL), PL excitation, temperature-dependent PL, and time-resolved PL techniques. We observed donor-to-acceptor-pair transition at about 3.24 eV with its phonon replicas with a periodic spacing of about 72 meV in the PL spectra of antimony-doped ZnO (ZnO:Sb) thin films at 12 K. We also investigate thermal activation energy and carrier recombination lifetime for the samples. Our result reflects that the antimony doping can generate shallow acceptor states, leading to a good p-type conductivity in ZnO.

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Surface Characteristics of Porous Ti-6Al-4V Implants Fabricated by Electro-Discharge-Sintering in a Low Vacuum Atmosphere (저진공 분위기 전기방전소결에 의해 제조된 다공성 Ti-6Al-4V 임플란트의 표면특성 연구)

  • Hyun, C.Y.;Huh, J.K.;Lee, W.H.
    • Korean Journal of Materials Research
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    • v.16 no.3
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    • pp.178-182
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    • 2006
  • A single electro-discharge-sintering (EDS) pulse (1.0 kJ/0.7 g), from a $300{\mu}F$ capacitor, was applied to atomized spherical Ti-6Al-4V powder in a low vacuum to produce porous-surfaced implant compacts. A solid core surrounded by a porous layer was formed by a discharge in the middle of the compact. XPS (X-ray photoelectron spectroscopy) was used to study the surface characteristics of the implant material. C, O, and Ti were the main constituents, with smaller amounts of Al, V, and N. The implant surface was lightly oxidized and was primarily in the form of $TiO_2$ with a small amount of metallic Ti. A lightly etched EDS implant sample showed the surface form of metallic Ti, indicating that EDS breaks down the oxide film of the as-received Ti-6Al-4V powder during the discharge process. The EDS Ti-6Al-4V implant surface also contained small amounts of aluminum oxide in addition to $TiO_2$. However, V detected in the EDS Ti-6Al-4V implant surface, did not contribute to the formation of the oxide film..

Polymer thin film organic transistor characteristics with plasma treatment of interlayers (플라즈마 표면처리에 따른 유기트랜지스터 특성)

  • Lee, Boong-Joo
    • The Journal of the Korea institute of electronic communication sciences
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    • v.8 no.6
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    • pp.797-803
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    • 2013
  • In this paper, we fabricated insulator thin films by plasma polymerization method for organic thin film transistor's insulator layer. For improving the electrical characteristics of organic transistor, we treated the semiconductor thin film with $O_2$ plasma. As results, the surface energy of organic transistor was increased from $38mJ/m^2$ to $72mJ/m^2$ and the mobility of organic transistor was increased $0.057cm^2V^{-1}s^{-1}$, that is increased 29% average ratio. Therefore, we have known that oragnic transistor's mobility can improve with plasma treatment of semiconductor thin film's surface.