• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1996년도 춘계학술대회논문집
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• pp.110-120
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• 1996

A crank-slider mechanism is driven by the rotating disk with are crank-pin guide to be applied to the deep drawing and cold forging presses. Load characteristics for different presses are summarized to see the basics of deep drawing of sheet metal and forging in terms of load-stroke relationship. Several types of conventional deep drawing presses are also shown to be compared with the ratating disk-types press. Kinematic performances by thearc guide driving mechanism are anlayzed in terms of load capaicty, stroke, and slide velocity characteristics, and they are compared with those by conventional driving , e.g. Niagara-typepress and so on. Kinematically better performances is shown by arc guide drive than those by conventional ones. The new driving mechanism is also proven to be one of the best for mass production press in terms of short cycle time. Possible applications of the arc guide press to deep drawing and cold forging work are in terms of kinematics and load capacity.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2004년도 한국우주과학회보 제13권2호
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• pp.376-379
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• 2004

Operational orbit determination (OOD) depends on the capability of generating accurate prediction of spacecraft ephemeris in a short period. The predicted ephemeris is used in the operations such as instrument pointing and orbit maneuvers. In this study the orbit prediction problem consists of the estimating diverse arc length orbit using GPS navigation data, the predicted orbit for the next 48 hours, and the fitted 30-hour arc length orbits of double differenced GPS measurements for the predicted 48-hour period. For 24-hour orbit arc length, the predicted orbit difference from truth orbit was 205 meters due to the along-track error. The main error sources for the orbit prediction of the Low Earth Orbiter (LEO) satellite are solar pressure and atmosphere density.

• 한국세라믹학회지
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• 제46권5호
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• pp.497-504
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• 2009

DLC is considered as the candidate material for application of moving parts in automotive components relatively in high pressure and temperature operating conditions for its high hardness with self lubrication and chemical inertness. Different deposition method such as arc plating, ion gun plating and PECVD were used for comparing mechanical and tribological properties of each DLCs deposited on stainless steel with 1 um thick respectively. Among these 3 types of DLCs, the arc plated DLC film showed highest value for wear resistance in dry condition. From the results of analysis for physical properties of DLC films, it seems that the adhesion force and crack initiation modes were more important factors than intrinsic mechanical properties such as hardness, elastic modulus and/or roughness to the wear resistance of DLC films. Raman spectroscopy was used for understanding chemical bonding natures of each type of DLC films. Typical D and G peaks were identified based on the deposition method. Hardness of the coating layers were identified by nanoindentation method and the adhesions were checked by scratch method.

• Journal of Electrical Engineering and Technology
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• 제5권2호
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• pp.264-269
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• 2010

This paper presents the analysis of the dielectric characteristics of a hot $SF_6$ gas in a gas circuit breaker. Hot gas flow is analyzed using the FVFLIC method considering the moving boundary, material properties of real $SF_6$ gas, and arc plasma. In the arc model, the re-absorption of the emitted radiation is approximated with the boundary source layer where the re-absorbed radiation energy is input as an energy source term in the energy conservation equation. The breakdown criterion of a hot gas is predicted using the critical electric field as a function of temperature and pressure. To validate the simulation method, breakdown voltage for a 145kV 40kA circuit breaker was measured for various conditions. Consistent results between the simulation and experiment were confirmed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 C
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• pp.1665-1667
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• 2003

Recently, a breaking capacity increases with breaking method using gas pressure from ablation materials in low voltage circuit breakers. In this paper, we investigated arc quenching materials with spectroscopic method. Especially, Hydrogen spectrum was investigated because its dielectric characteristics are better than other gases. We selected two arc quenching materials, UP and PA6, that use in circuit breakers. They had hydrogen spectrums, but PA6 was better than UP in the qualitative aspect.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2007년도 추계학술대회 논문집
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• pp.140-141
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• 2007

The arc ion plating (AIP) technique has been used widely for thin coating in the area of surface engineering. The TiN coating is important in the field of dies, cutting tools and other mechanical parts. When forming the TiN films by AIP technique, the processing parameters such as arc power, bias voltage, working pressure, temperature of substrate and pre-treatment affected the adhesion respectively. The results of scratch test revealed that the adhesion strength was influenced by arc power most strongly. And a sequence of the importance of each parameters has been obtained. The crystal structure and cross-section of TiN films are also be investigated.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.1109-1112
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• 2004

This study reports on the pressure relief design and braided composite of surge arrester. Surge arresters with porcelain housing must not have explosive breakage of the housing to minimize damage to other equipment when subjected to internal high short circuit current. As a solution, this study describes pressure relief design performance of arresters with braided composite module. In general, braided composite has Potential for improved impact and delamination resistance. Manufacturing processes of the braided composite could also be automated and could potentially lead to lower costs. Therefore, in consideration of characteristics of pressure relief for polymer arrester, the fabric pattern of braided composite was decided. And Polymer arrester module was manufactured with braid. The mechanisms of pressure occurrence and relief were investigated basically by analyzing arc energy and the correlation between thermal shock and indoor pressure in pressure relief test.

• 수산해양기술연구
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• 제21권1호
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• pp.12-18
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• 1985

고압변압기의 1차측을 제어하고 2차측에 유도된 전압을 이용한 수중방전음원의 전기음향학적 제특성을 분석.검사한 결과는 다음과 같다. 1. 방전시 2차측 전류는 초기에는 Ohm 법칙을 따르다가 전류가 최고 6.3A 흘러 절연 파괴되었으며, 그 순간 방전음이 생성되었다. 2. 전류인가점과 방전음 생성문의 시간차는 약 3ms였으며, 전압이 최고일 때 절연파괴가 일어나 방전음이 생성되었다. 3. 전극의 끝이 뾰족할수록 2차측 전압이 높을수록 음압수준은 높았다. 4. 뾰족한 형태의 전극은 전극간격이 100cm일 때도 방전이 일어났으며 전극간격이 1cm이상부터 비교적 안정된 방전음이 생성되었다. 5. 방전음의 펄스폭은 약 0.15ms인 Shock Wave였으며, 10HKz 이하의 합성저주파 성분이었다.

• 동력기계공학회지
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• 제8권1호
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• pp.24-29
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• 2004

In this study, a computer analysis has been developed for predicting the pipe pressure of the intake and exhaust manifold. To obtain the boundary conditions for a numerical analysis, one dimensional and non-steady gas dynamic calculation is performed by using the MOC(Method Of Characteristic). The main numerical parameters are the variation of the engine revolution to calculate the pulsating flow which the intake and exhaust valves arc working. The comparison of exhaust pressure in case of numerical results is quite matched with in case of experimental results. When engine revaluation is increased, the pressure amplitude showed a high value, but the pressure frequency was decreased.

• Journal of Mechanical Science and Technology
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• 제20권10호
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• pp.1716-1721
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• 2006

The Lubrication Mode of line contacts between the vane and the camring in an oil hydraulic vane pump has been investigated. First, the variations of the radial force of a vane were calculated from previous measurements of dynamic internal pressure in four chambers surrounding a vane. Next, the lubrication modes were distinguished with Hooke's chart, which is an improvement over Johnson's chart. Finally, the influence of the boundary conditions in the lubrication region on the fluid film lubrication was examined by calculating the film pressure distributions. The results showed that the lubrication mode of the vane tip exists in the rigid-variable-viscosity region, and that discharge pressure higher than 7 MPa greatly affects the oil film pressure in the small and the large arc section because of the Piezo-viscous effect.