• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 추계학술대회 논문집 학회본부
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• pp.581-583
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• 1997

In this paper, we present a temperature characteristic in OPGW link due to meteological effects. we measured a temperature on a 2km OPGW using a distributed optical fiber temperature sensing system. The measurement showed that OPGW temperature was several degrees lower to ambient atmospheric temperature in the nighttime and several degrees higher than that in the daytime due to sunshine. It'll be used for a reference data of the transmission delay variations in OPGW link due to meteorological effects.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1996년도 추계학술대회 논문집
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• pp.214-217
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• 1996

In this paper. we deal wish the I-t characteristic of law voltage distribution fuse. It is used to be thermal characteristic in being produced at fuse element part. The elements are divided low temperature melting element(LTME) by high temperature melting element(HTME). Those parts make of coordination. The characteristic of fuse is decided by material and design etc. used at element. We analysis I-t characteristic curve by using the numerical method. And we compared the curve of simulation with that of experiment

• 한국기계가공학회지
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• 제17권1호
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• pp.138-143
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• 2018

In general, the operating temperature of electronic equipment is closely related to product life and reliability, and it is recognized that effectively cooling the parts is an important problem. In this paper, an experimental study on the cooling characteristic according to the pin array of the heat sink is conducted. The experiment on the heat sink was based on the natural convection and temperature distribution changes. The experimental results indicate that the pin array of the heat sink has an effect on the thermoelectric module's cooling characteristic.

• 전기의세계
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• 제25권2호
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• pp.87-91
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• 1976

Experimentally to investigate the conductive characteristic of oil-immersed paper, we observed the leakage current-voltage characteristic of oil-immersed paper, the temperature dependence of ionization rate and the effect of metal electrode on the leakage current. The results showed that the leakage current-voltage characteristic generally followed the experimental equation i=i$_{0}$ exp (K.root.E) and the slope K did not change by the temperature and electric strength, but only when the direct voltage was applied. And also the leakage current seemed to depend on the work function of metal electrode. From the above results we concluded that the deterioration of oil-immersed paper was not only caused by the thermionic emission from the cathode but also by the conductive property of oil-immersed paper in itself and the work function of metal electrode.e.

• ETRI Journal
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• 제28권3호
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• pp.347-354
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• 2006

The characteristic variation of 3-dimensional (3-D) solenoid-type embedded inductors is investigated. Four different structures of a 3-D inductor are fabricated by using a low-temperature co-fired ceramic (LTCC) process, and their s-parameters are measured between 50 MHz and 5 GHz. The circuit model parameters of each building block are optimized and extracted using the partial element equivalent circuit method and an HSPICE circuit simulator. Based on the model parameters, the characteristics of the test structures such as self-resonant frequency, inductance, and quality (Q) factor are analyzed, and predictive modeling is applied to the structures composed of a combination of the modeled building blocks. In addition, characteristic variations of the 3-D inductors with different structures using extracted building blocks are also investigated. This approach can provide a characteristic estimation of 3-D solenoid embedded inductors for structural variations.

• 한국항공우주학회지
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• 제36권2호
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• pp.115-122
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• 2008

예조건화 오일러 방정식의 수렴 특성에 미치는 특성 조건수의 영향을 조사하였다. 그리고 Choi와 Merkle 예조건화를 적용한 경우와 온도 예조건화를 적용한 경우의 수렴 특성을 분석하였다. 공간차분을 위해 예조건화 Roe의 FDS 기법을 적용하였고, 시간적분을 위해 예조건화 LU-SGS 기법을 적용하였다. 지배방정식의 수렴 특성은 특성 조건수에 크게 영향을 받는 것으로 나타났으며, 최적의 특성 조건수가 존재하는 것으로 나타났다. 그리고 최적의 특성 조건수는 Choi 와 Merkle 예조건화를 적용한 경우와 온도 예조건화를 적용한 경우가 서로 다른 것으로 나타났다.

• 한국전기전자재료학회논문지
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• 제19권3호
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• pp.240-245
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• 2006

Recently, as the road capacity reaches the limit and environmental problems becomes serious, there is gradually increased a need for railroad vehicles that are environment-friendly and have time regularity, reliability, and safety. Accordingly, in addition to conventional railroad vehicles, lots of vehicles are being newly developed. In this study, temperature sensors were adhered to transformer that is used in KHST(Korean High-Speed Train) to verify variation of temperature characteristics about transformer synthetically and efficiently. In the case that temperature of transformer exceeds reference temperature for running of KHST, overheating of transformer may cause a fatal accident of vehicle. Therefore, after on-line measuring system was constructed in vehicle, oil temperature and tank temperature were measured on real-time. Characteristics and main specifications of transformer in KHST were described in this paper. Also, measuring system for temperature measurement of transformer was explained in brief. Temperature data of transformer was acquired using measuring system, KRRI(Korea Railroad Research Institute) analyzed characteristic in contrast with comparing with temperature of transformer about month, running speed and running time.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2004년도 제29회 KOSCI SYMPOSIUM 논문집
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• pp.213-216
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• 2004

The results of combustion performance test of fuel-rich gas generator(GG) using LOx and kerosene as propellant at design and off-design point are described. The parameters used in this analysis are the average exit temperature($T_{GG}$) and the characteristic velocity($C^{\ast}$). The average gas temperature at the exit of gas generator is found to be a function of propellant O/F ratio. For the gas generator having residence time of 4msec or more, the effect of flame residence time and combustion chamber pressure on the exit temperature is not significant. The exit characteristic velocity is found to be linearly proportional to the gas temperature at the exit of gas generator.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.311-318
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• 2001

A three-dimensional numerical analysis of the flow and heat transfer characteristic of wood-flour-filled polypropylene melt in an extrusion die was carried out Used for this analysis were Finite Concept Method based on FVM, unstructured grid and non-Newtonian fluid viscosity model. Temperature and flow fields are closely coupled through temperature dependent viscosity and viscous dissipation. With large Peclet, Nahme, Brinkman numbers, viscous heating caused high temperature belt near die housing, Changing taper plate thickness and examining some predefined parameters at die exit investigated the effect of taper plate on velocity and temperature uniformities. In the presence of taper plate, uniformity at die exit could be improved and there existed an optimum thickness to maximize it.

• 열처리공학회지
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• 제7권4호
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• pp.298-306
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• 1994

This study was performed to investigation the effect of austempering temperature on the mecanical properties and fracture Characteristic of the ductile cast iron with contains Cu and Mo. The obtained results of this study were as follows; Microstructure of austemped ductile cast iron obtained by austempering were low bainite with some martensite at $250^{\circ}C$, mixture of low and upper bainite at $300^{\circ}C$ and upper bainite at $350^{\circ}C$. With increasing austempering temperature, yield strength, tensile strength and hardness decreased, while the elongation and impact absorption energy increased. With increasing austempering temperature, fracture toughness value increased and mainly controlled by bolume fraction of retained austenite. The volume fraction of retained austenite increased and the fracture surface obtained fibrous and dimple with increasing austempering temperature.