• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1997년도 제25회 춘계학술대회
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• pp.101-110
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• 1997

An experimental study was performed to discover the tribological behaviors of pure silver coated 52100 bearing steel. Pure silver coatings ranging from 80 nm to several micrometers were produced by a thermal evaporation coating method. Experiments using a thrust ball bearing-typed rolling test-rig were performed for the investigations of the influence of coating thickness on the tribological rolling behavior. The existence of optimum film thickness which revealed minimum rolling resistance was discovered. A careful analysis on the contact surfaces for the optimum film thickness has been performed. The contact patches produced by the transferred silver films played an important role for the rolling resistance to keep low.

• Tribology and Lubricants
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• 제13권3호
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• pp.85-92
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• 1997

An experimental study was performed to discover the tribological behaviors of pure silver coated 52100 bearing steel. Pure silver coatings ranging from 80 nm to several micrometers were produced by a thermal evaporation coating method. Experiments using a thrust ball bearing-typed rolling test-rig were performed for the investigations of the influence of coating thickness on the tribological rolling behavior. The existence of optimum film thickness which revealed minimum rolling resistance was discovered. A careful analysis on the contact surfaces for the optimum film thickness has been performed. The contact patches produced by the transferred silver films played an important role for the rolling resistance to keep low.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2008년도 추계 학술논문 발표대회
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• pp.49-52
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• 2008

The present study was to develop a dry PFB method similar to the existing gypsum board construction method in order to apply the existing wet PFB method that uses fire-resistant adhesive. It was found that the existing wet method can produce concrete compressive strength of 80MPa and fire resistance of 3 hours with 30mm PF boards. The goal of development in this study was fire resistance of 3 hours through dry construction of 15mm fire-resistant boards. 1. Improved PF board was prepared by adding inorganic fiber to existing board and using aggregate with grain size of 3mm or less. Molding was done at temperature higher than that for existing PF board molding. While wet curing is used for existing PF boards, this study used dry curing in order to enhance heat insulation performance. 2. According to the results of fire resistance test, when the dry PF method was applied, the temperature of the main reinforcing bar was 116℃ in 15mm, 103.8℃ in 20mm, and 94℃ in 25mm, and these results satisfied the current standards for fire resistance control presented by the Ministry of Land, Transport and Maritime Affairs. When a 3-hour fire resistance test was performed and the external properties of the specimen were examined, the outermost gypsum board hardly remained and internal PF board maintained its form without thermal strain.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 1996년도 특별강연 및 춘계학술발표 개요집
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• pp.133-135
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• 1996

• 한국태양에너지학회 논문집
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• 제35권1호
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• pp.61-68
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• 2015

The advanced counties effort to the supplement of the zero energy buildings for the global building energy saving. In the middle of the development of passive technology, the government has to effort to the energy saving of buildings by enhanced performance of the window thermal insulation. By the method of enhanced performance of window thermal insulation, the use of vacuum double glazing saves the energy consumption in building. This glazing has low U-value(heat transmission coefficient) than normal double glazing. The vacuum glazing enhanced thermal insulation performance by vacuum space of between the glass and glass. For this vacuum glazing, pillar maintain the space between glass and glass. But this structure cause the raising the heat transmission coefficient in pillar approaching glass. This study confirmed the U-value by the test method of thermal resistance for windows and doors. Also this study confirmed the variation of heat transmission coefficient by the structure of vacuum glazing. And this study measured the surface temperature of the vacuum glazing about pillar approaching glass and vacuum space in cool chamber and hot box. That result, this study confirmed U-value of $0.422W/m^2{\cdot}K$ of vacuum glazing. Also this study confirmed U-value of $0.300{\sim}0.422W/m^2{\cdot}K$ by various the structure of vacuum glazing. And this study confirmed the heat flow in pillar approaching glass.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.101-106
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• 2005

During braking at a train, thermal energy is generated due to the frictions between disk and lining and wheel and shoe. In general, the braking transfers the kinetic energy into thermal energy. Therefore. the frictional characteristics are varied according to the braking force, the thermal resistance, and the thermostable, etc. Using a Dynamo testing we have studied the frictional characteristics and the thermal distribution to investigate a stable speed and to improve the testing method through comparing and analysing in the measurement or the thermocouple temperature and infrared camera.

• The International Journal of Costume Culture
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• 제7권2호
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• pp.103-111
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• 2004

The shrinkproof-finished wool fibers treated with resin coating and chlorination methods were used to find out an optimal shrinkproof finishing method keeping the quality properties of wool fabric to manufacturers. Shrinkage during repeated washing, electrostatic propensity, thermal resistance and pilling propensity of shrinkproof-finished wool knits, and analysis of finishing methods were measured. Upon the results from the surface examination of shrinkproof-finished wool fibers, the patterns of scale layer and degree of scale removal were subject to change according to the finishing processes. The shrink resistance was significantly enhanced on repeated washing of shrinkproof-finished knits, especially, chlorinated wool. Addition of strong physical force and alkali detergent applied in this washing experiment brought about superior effects with the low shrinkage rate although it was very severe washing conditions for wool fabrics. The results from the washing experiment implies that shrinkproof-finished knitted fabrics can be machine washed at individual households with other ordinary laundry. There was some changes and variation found in thermal resistance, electrostatic propensity, and pilling, however, it seems to be minor within standard limits. Therefore, shrinkproof-finished knitted fabrics did not bring serious changes to other physical properties comparing with original wool, which helps consumers handle wool knitted clothes more conveniently.

• Corrosion Science and Technology
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• 제9권6호
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• pp.325-330
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• 2010

Many surface protection methods have been developed to apply for constructional steels used under severe corrosive environment. Thermal spray coating has been known to be an attractive technique due to its relatively high coating speed. Furthermore high corrosion resistance of coated film with thermal spray is required to expand its application. Four types of coated films(DFT:300 um) such as pure zinc, pure aluminum and two Al-Zn alloy (Al:Zn=85:15 and Al:Zn=95:5) onto the carbon steel (SS401) were prepared with arc spray, and the corrosion behavior of their samples were evaluated by electrochemical method in this study. Pure aluminum sample showed high corrosion resistance behavior exposed to sea water solution and pure zinc and alloy (Al:Zn=95:5) samples followed pure aluminum sample. The other alloy(Al:Zn=85:15) so called galvalume coated onto the carbon steel ranks the 4th corrosion resistance in this study. The results of porosity ratio of those samples by observation are well matched with the electrochemical data.

• Journal of Welding and Joining
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• 제9권3호
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• pp.41-51
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• 1991

The thermomechanical coupling phenomena in the resistance welding process is complicated due to interactions of mechanical, thermal and electrical factors. Although experimental investigations of resistance spot welding have been carried out, but there are a few by computer simulation. so the purpose of this research is to decrease the time and cost much required in experimental investigation by carrying out the analysis of the resistance spot welding process through computer simulation based on the finite element method. The tool used in the computer simulation is the commercial ANSYS program package. A two dimensional axisymetric model is used to simulate the resistance spot welding for two stainless steel sheets of equal thickness and parametric study is carried out for variable welding current, workpieces of unequal thickness and dissimilar materials. The results from the computer simulation are in good agreement with the experimental one. Through these results, such items as stress distribution, temperature profiles, thermal expansion and weld nugget formation are predicted. Reliability and applicability of finite element models have been demonstrated to simulate and to analyze the resistance spot welding process.

• Composites Research
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• 제15권5호
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• pp.27-34
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• 2002

본 연구의 목적은 (주)한국와이바의 CF3327 평직 복합재료의 열전도도를 실험적으로 계측하고 이를 이론적인 예측과 비교하는데 있다. 열전도도 계측을 위하여 비교계측법의 원리를 이용한 실험 장치를 제작하였으며 열전도도가 잘 알려진 그라파이트를 실험함으로써 장비의 정확성을 확인하였다. 미시역학적인 방법은 섬유 및 기지의 물성, 섬유체적비, 직조 형태 등의 변수들이 복합재료의 유효물성치에 미치는 영향을 평가하는데 유용하다. 본 연구에서는 3차원 직-병렬 열저항 개념을 주기적으로 반복되는 평직의 단위구조에 적용하여 열전도도를 예측하였다. 해석 결과를 실험 결과와 비교한 결과 잘 일치함을 확인하였고 섬유체적비가 에폭시 수지 복합재료의 열전도도에 미치는 영향을 고찰하였다.