• Journal of Advanced Marine Engineering and Technology
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• 제28권6호
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• pp.962-971
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• 2004

This paper has dealt with thermo-physical properties of microencapsulated phase change material slurry as a latent heat storage material having a low melting point. The measured results of the thermo-physical properties of the test microencapsulated phase change material slurry, those are, density, specific heat, thermal conductivity and viscosity, were discussed for the temperature region of solid and liquid phases of the dispersion material (paraffin). The measurements of these properties of microencapsulated phase change material slurry have been carried out by using a specific-gravity meter, a water calorimeter, a differential scanning calorimeter(DSC), a transient hot wire method and rotating type viscometer, respectively. It was clarified that the additional properties law could be applied to the estimation of the density and specific heat of microencapsulated phase change material slurry and also the Euckens equation could be applied to the estimation of the thermal conductivity of this slurry.

• 대한가정학회지
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• 제17권4호
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• pp.15-22
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• 1979

This paper was studied changes of physical properties of Lining fabrics by washing and difference between dry method. I experimented four kinds of Lining fabrics for the sample . The analysis was performed by correlation coefficient analysis and significance tested between correlation coefficients. The results are summarized as follows : 1) Increasing rate of shrinkage tends to call high density and weight. 2) Rayon fabrics is shown the most high rate of shrinkage and decreasing strength by increasing washing times. 3) Drip dry makes little change of physical properties. 4) Polyester fabrics is little by washing times and dry method.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1991년도 가을 학술발표회 논문집
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• pp.1-4
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• 1991

Relationship between againg and characteristic change of asphalt is not well known through asphalt rheolopy. Therefore, this study was conducted to evaluate characteristic change of asphalt cement due to againg based on experimental results of chromatogram and selected physical properties. Currently, three virgin asphalt cements were tested for physical properties and chromatograms before and after artificially conditioning for againg. Results in the current study showed that againg caused significant changes of physical properties and increase of larger size molecules and approximately corresponding reduction of smaller size molecule in asphalt cement molecular size distribution.

• 패션비즈니스
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• 제8권5호
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• pp.31-40
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• 2004

The purpose of this study is to investigate the change of the physical properties, bending and luster properties, which are related to the touch and appearance of silk fabrics modified by the degumming process. The silk has long been known as one of the most elegant and soft textile materials. The raw silk yarn, or cocoon bave, spun from the spinneret, is rather stiff due to the sericin covering the two fibroins together. The sericin can be removed during a degumming process. The removal of the sericin would result in remarkable change in the physical properties of the raw silk fabrics, including luster of the fabrics, which process parameters could possibly be utilized to adequately control the silk fabric properties. The KES(Kawabata Evaluation System) is a testing methodology that has been used with considerable success for predicting the hand and tailorability of apparel fabrics. This study uses one of the KES, bending tester, to measure the bending properties of the silk fabrics degummed for specified period to change the physical/mechanical properties of the fabric. The KES bending measurement revealed that the bending rigidity decreased for both the warp and weft direction of the silk fabrics with the increase of the degumming period. It has been shown in this study that the some of the hand-related physical properties, including the bending rigidity, drapability, and luster, could be modified with the change in the degumming period.

• Tribology and Lubricants
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• 제28권2호
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• pp.93-98
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• 2012

The engine oil is an oil used for lubrication of various internal combustion engines. Recently, the vehicle and engine oil manufacture usually guarantee for oil change over 15000~20000 km mileage, but the most of driver usually change engine oil every 5000 km driving in Korea. In this case, it is possible to cause environmental contamination by used engine oil and increase the cost of driving by frequently oil change. In this study, we investigate the various physical properties such as flash point, pour point, kinematic viscosity, cold cranking simulator, total acid number, and four-ball test for fresh engine oil and used engine oil after vehicle driving (5000 km, 10000 km). The test result showed that the total acid number and wear scar by four-ball test of used engine oil had increased than fresh engine oil, but 2 kind of used oil (5000 km and 10000 km) had similar physical properties.

• 한국도로학회논문집
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• 제4권4호
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• pp.53-66
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• 2002

아스팔트는 노화에 따라 물리적 특성변화가 일어난다. 하지만 같은 수준으로 노화시킨 아스팔트 혼합물들임에도 골재와 결합재 등에 따라 서로 다른 강성이나 취성을 보인다. 이는 노화에 의한 바인더 특성 변화의 차이에 기인한 것인데 이와 같이 혼합물 내에서 바인더의 물리적 특성 변화 차이에 영향을 주는 요인에 대한 연구는 별로 없다. 따라서 본 연구에서는 아스팔트 혼합물의 노화 후추출한 바인더의 물리적 특성을 측정하고 물성 차이에 영향을 미치는 요인을 분석하였다. 폴리머 3종류와 골재 두 종류, 두 가지 입도, 두 종류의 아스팔트를 사용하여 32종류의 혼합물을 제조하고, 이를 장 단기 노화 처리하였다. 각 혼합물의 노화 후 Abson recovery 방법으로 바인더를 추출 회생하고 바인더 물성 시험(침입도, 동점도, 절대점도)을 수행하였다. 이를 SAS를 이용하여 통계 분석하였다. 바인더 시험에서 골재 종류와 폴리머가 노화시 물성변화에 차이를 가져오는 심각한 요인임을 알 수 있었고, 입도는 점도 변화에 큰 영향을 미치는 인자인 것임을 확인할 수 있었다. 본 연구 결과, 혼합물 내의 바인더 물성은 골재 종류, 입도, 개질제의 종류, 바인더의 종류 등의 다양한 요인에 의해 많은 영향을 받는 다는 것을 알 수 있었다.

• 한국연초학회지
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• 제20권1호
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• pp.13-18
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• 1998

In the flue curing process, the wet bulb temperature is usually controlled at a constant level. To improve the quality of flue cured leaves, we studied the effect of the cyclic change of wet bulb temperature at the yellowing stage of flue curing on physical properties of cured leaves. The wet bulb temperature was automatically controlled between preset high (38℃) and low point (35℃) every one hour cyclically. As a result, the acceleration of the increase in the physical properties of cured leaves were observed. The leaves cured by this method were more or less orange in color, better bodied, and less brittle compared with the leaves produced by conventional curing. However, the leaves cured by this method had a little sharpness and harshness. As to the physical properties, there was decreased in occurrence of flat leaves than that of conventional ones. On the other hand, in case of cyclic curing method, increase of price per kg reached to 2-3% compared with those of conventional ones.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.156-159
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• 2002

This study reports on physical properties of the noise radiation caused by expansion of exhaust gas and vibration of pumps according to change of vaccum degree. The fundamental responses show that the sound power level radiated is proportional to the common logarithm of the degree of vaccum.

• 암석학회지
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• 제20권3호
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• pp.141-149
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• 2011

암석의 물리적 특성 변화에 대해 온도의 영향을 연구하기 위해 2종의 화강암류와 대리암, 사암을 전기로에서 $400^{\circ}C$와 $600^{\circ}C$로 가열하였다. 모든 시료에서 가열 후 물리적 특성(비중, 공극률, 흡수율, 초음파속도)과 색상 변화는 보이나, 편광현미경을 이용한 광물학적 변화는 뚜렷하지 않다. 특히 물리적 특성 변화에서 공극률과 흡수율은 증가하고, 비중과 초음파 속도는 감소하는 경향을 보이며, 온도가 증가할수록 변화폭은 크게 나타난다. 여기서 측정한 공극률은 암석의 전체 공극률을 반영하지 못하고 있으나 온도에 의한 암석의 표면 상태 변화를 반영한다 반면 초음파 속도는 암석의 전체적인 손상 정도를 파악하는데 유용하다. 그러므로 온도에 의한 암석의 물리적 특성 변화를 설명하기 위해 공극률과 초음파 속도는 상호 비교해야 한다.

• 한국의류학회지
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• 제23권6호
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• pp.853-863
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• 1999

the change of physical properties (thickness, weight, air permeability) and mechanical properties(abrasion resistance breaking load and displacement) of samples were determined after heat exposure by a RPP tester. The effect of exposure time and heat flux intensity on the changes and the relationship between physical properties and mechanical properties were investigated. FR treated cotton Kevlar/PBI and Nomex with different structureal characteristics were chosen for specimens. The changes of physical properties and mechanical properties were calculated based on their initial values before heat exposure. The longer exposure time and the high heat flux intensity the more changes of those properties. Heat flux intensity was more effective on the changes, The showed to be affected by an interplay of shrinkage and pyrolysis products loss. The changes of thickness and abrasion resistance showed to be higher for plain weave fabric and those of air permeabiliyt and breaking load and displacement for twill weave fabric. While FR treated cotton which have high RPP value experienced serious and detrimental changes after heat exposure Kevlar/PBI which has low RPP value showed no high changes. In conclusion it could be confirmed that when total performance of a protective clothing is estimated retention capability of physical and mechanical properties after heat exposure as well as RPP value must be considered.