• 전기의세계
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• 제25권5호
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• pp.3-12
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• 1976

일본에서는 송전전압 500kV 이상의 전압에 의한 송전을 초초고압송전이라고 부르고 있다. 1952년 신북육간선이 초고압 275kV로 운전개시한 이래 1973년 초초고압 500kV 방총간선이 운전개시하기까지의 약 20년간 초고압 275kV 송전이 주간선으로서 활약하였다. 500kV 송전을 실현하는데 있어서 해명해 두어야 할 기술적 문제에는 여러가지가 있겠지만 우선 송전전압이 275kV의 2배가까이 승압됨으로 여기에 따른 송전선료 및 변전소의 외부전연 및 변압기의 절연문제등이 큰 문제로 될 것이다. 여기서는 1.운전전압과 송전용량에 대해서 2.운전전압 및 상용주파과전압에 대해서 3.송전선의 코로나방잔과 도체설계에 대해서 4.송전선의 절연설계에 대해서의 4가지 문제에 초점을 맞추어 그 내용을 간단히 설명하여 보기로 한다.

• Proceedings of the KIEE Conference
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1736-1738
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• 2002

Oil-filled power cables and XLPE power cables have been globally applied for extra-high-voltage underground power transmission lines. The application of XLPE cables for the transmission lines have been largely increased at the domestic and overseas projects because of some issues. O.F cables have some week points, related with the issues of the environmental pollution and the needed maintenance work, even though they have been applied for several ten years and their reliability has been proven. Meanwhile, the demands on XLPE power cables increase as their manufacturing technologies have been improved and their simplicity of installations has been focused on. In Korea, for the first time, the 275kV XLPE cable is to be applied at an overseas power plant project. This paper introduces the project profile, the design of the XLPE cable and its accessories, the cable system design and the installation design.

• Proceedings of the KIEE Conference
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.2057-2059
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• 2000

The underground transmission system has been internationally developing the voltage class of which increase to realizing high reliability and efficiency. Under this situation, if a company don't do much labor to elevating one's technology, the company will be hard to compete against other companies in trade. Our company has successfully developed 275kV oil-filled cable and its accessory in 1999 for Malaysia project, which was based on accumulated technological know-how, which is the highest voltage level among awarded oversea underground transmission networks in Korea. The power cable and its accessories were subjected to type approval test in accordance with IEC 60141-1 and TNB tender documents. This paper describes the main features of the type approval tests of the cable and its accessories.

• Journal of Sensor Science and Technology
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• 제29권4호
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• pp.275-278
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• 2020

In this study, we evaluated the temperature-dependent characteristics of homojunction InGaAs vertical Fin-shaped Tunnel Field-Effect Transistors (Fin TFETs), which were fabricated using a novel nano-fin patterning technique in which the Au electroplating and the high-temperature InGaAs dry-etching processes were combined. The fabricated homojunction InGaAs vertical Fin TFETs, with a fin width and gate length of 60 nm and 100 nm, respectively, exhibited excellent device characteristics, such as a minimum subthreshold swing of 80 mV/decade for drain voltage (V_DS) = 0.3 V at 300 K. We also analyzed the temperature-dependent characteristics of the fabricated TFETs and confirmed that the on-state characteristics were insensitive to temperature variations. From 77 K to 300 K, the subthreshold swing at gate voltage (V_GS) = threshold voltage (V_T), and it was constant at 115 mV/decade, thereby indicating that the conduction mechanism through band-to-band tunneling influenced the on-state characteristics of the devices.

• Journal of Powder Materials
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• 제17권4호
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• pp.289-294
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• 2010

For the aim of low-temperature co-fired ceramic microwave components, sintering behavior and microwave properties (dielectric constant ${\varepsilon}_r$, quality factor Q, and temperature coefficient of resonant frequency ${\tau}_f$) are investigated in $Bi_{18}O(Ca_{0.725}Zn_{0.275})_8Nb_{12}O_{65}$ [BCZN] ceramics with addition of $V_2O_5$. The specimens are prepared by conventional ceramic processing technique. As the main result, it is demonstrated that the additives ($V_2O_5$) show the effect of lowering of sintering temperature and improvement of microwave properties at the optimum additive content. The addition of 0.25 wt% $V_2O_5$ lowers the sintering temperature to $890^{\circ}C$ utilizing liquidphase sintering and show the microwave dielectric properties (dielectric constant ${\varepsilon}_r$ = 75, quality factor $Q{\times}f$ = 572 GHz, temperature coefficient of resonance frequency ${\tau}_f\;=\;-10\;ppm/^{\circ}C$). The estimated microwave dielectric properties with $V_2O_5$ addition (increase of ${\varepsilon}_r$, decrease of $Q{\times}f$, shift of ${\tau}_f$ to negative values) can be explained by the observed microstrucure (sintered density, abnormal grain structure) and possibly high-permittivity $Bi_{18}Zn_8Nb_{12}O_{65}$ (BZN) phase determined by X-ray diffraction.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.275-275
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• 2008

This paper describe the fabrication of a Pd/polycrystalline 3C-SiC schottky diode and its characteristics, in which the polycrystalline 3C-SiC layer and Pd Schottky contact were deposited by using APCVD and sputter, respectively. Crystalline quality, uniformity, and preferred orientations of the Pd thin film were evaluated by SEM and XRD, respectively. Pd/poly 3C-SiC Schottky diodes were fabricated and characterized by I-V and C-V measurements. Its electric current density Js and barrier height voltage were measured as $2\times10^{-3}$ A/$cm^2$ and 0.58 eV, respectively. These devices were operated until about $400^{\circ}C$. Therefore, from these results, Pd/poly 3C-SiC Schottky devices have very high potential for high temperature chemical sensor applications.

• NEWSLETTER 전기공업
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• 96-23호통권168호
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• pp.23-37
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• 1996

• Journal of the Korean Society for Heat Treatment
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• 제15권4호
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• pp.172-177
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• 2002

The steady-static creep behaviors of Ti-6Al-4V alloy, using the constant stress creep tester, were investigated over the temperature range of $510{\sim}550^{\circ}C$(0.42~0.44Tm) and the stress range of 200~275 MPa($20.41{\sim}28.06kg/mm^2$). The stress exponents(n) for the static creep deformation of this alloy were 9.85, 9.35, 9.24 and 8.85 at the temperature of 510, 525, 535 and $550^{\circ}C$, respectively. The stress exponent(n) decreased with increasing the temperature and became close to about 5. The apparent activation energies(Q) for the static creep deformation were 254.4, 241.8, 234.4 and 221.9 kJ/mole for the stress of 200, 225, 250 and 275MPa, respectively. The activation energy(Q) decreased with increasing the stress. From the above results, it can be concluded that the static creep deformation for Ti-6Al-4V alloy was controlled by the dislocation climb over the ranges of the experimental conditions. Larson-Miller Parameter(P) for the crept specimens of Ti-6Al-4V alloy under the static creep conditions was obtained as $P=(T+460)({\log}\;t_r+21)$. The failure plane observed by SEM showed up dimple phenomenon at all range.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• 제26권4호
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• pp.275-277
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• 2013

Thin-film transistors(TFTs) with silicon zinc tin oxide(SZTO) channel layer are fabricated by solution-process. The threshold voltage ($V_{th}$) shifted toward positive directly with increasing Si contents in SZTO system. Because the Si has a lower standard electrode potential (SEP) than Sn, Zn, thus degenerate the oxygen vacancy (VO). As a result, the Si act as carrier suppressor and oxygen binder in the SZTO as well as a $V_{th}$ controller.

• Journal of Korean Public Health Nursing
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• 제32권2호
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• pp.275-287
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• 2018

Purpose: This study examined the trends of socio-demographic and health factors affecting the health-related quality of life (HRQoL) in Korean elderly. Methods: Data were obtained from the Fourth, Fifth and Sixth Korean National Health and Nutrition Examination Survey (KNHANES V-1, 2007, KNHANES V-1, 2010, KNHANES V-2, 2014). The sample consisted of 3,668 Korean individuals aged 65 years and older. The data were analyzed using a t-test, Chi-square test and multiple linear regression using the SPSS/WIN 20.0 program. Results: The HRQoL is improving consistently and the affecting factors on the HRQoL were the education level, activity limitation, subjective health and walking days per week in the three data of 2007, 2010, and 2014. Conclusion: A health care program focusing on improving activity limitation and physical activity should be considered for the improvement of HRQoL for the elderly in the community.