• 한국자기학회지
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• 제9권5호
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• pp.263-270
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• 1999

컴퓨터 하드디스크용 윤활제인 PFPE중 Z-DOL과 AM2001을 이용하여 pulling-up speed와 윤활제의 농도를 변화시키면서 윤활제의 두께변화를 알아보았으며, 또한 열처리를 통해 overcoat층인 carbon과 윤활제의 결합특성을 알아보았다. Pulling-up speed가 빠를수록, 그리고 윤활제의 농도가 증가할수록 윤활제의 두께는 두껍게 coating되었음을 알 수 있었으며, 또한 XPS을 이용하여 분석해 본 결과, overcoat층인 carbon에 존재하는 표면 오염물은 C-OH, CO가 지배적이었고, 열처리를 함으로써 overcoat층인 carbon과 윤활제의 결합력이 증진됨을 알 수 있었다.

• Carbon letters
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• 제2권1호
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• pp.9-14
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• 2001

Adsorption and desorption characteristics of methyl iodide at high temperature conditions up to $250^{\circ}C$ by TEDA-impregnated activated carbon, which is used for radioiodine retention in nuclear facility, was experimentally evaluated. In the range of temperature from $30^{\circ}C$ to $250^{\circ}C$, the adsorption capacity of base activated carbon decreased sharply with increasing temperature but that of TEDA-impregnated activated carbon showed higher value even at high temperature ranges. Especially, the desorption amount of methyl iodide on TEDA-impregnated carbon represented lower value than that on unimpregnated carbon. The breakthrough curves of methyl iodide in the fixed bed packed with base carbon and TEDA-impregnated activated carbon at high temperature were compared. TEDA-impregnated activated carbon would be applicable to adsorption process up to $150^{\circ}C$ for the removal of radioiodine in a nuclear facility.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.215-216
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• 2023

As the introduction of new climate system, efforts to change carbon neutrality, efforts to convert carbon neutrality. In Korea, we are setting up carbon emissions through greenhouse gas and energy target management system for business and companies that emit carbon emissions. The construction industry quantitatively predict the carbon emissions, but it is struggling to set up the amount of carbon emissions before construction stage, but it is suffering from lack of data. Therefore, this study was conducted by collecting data on the energy usage amount of carbon emissions according to the energy usage of the construction phenomenon and low-capacity prediction of the construction phenomenon. Through collected data, the average energy usage amount by building users and evaluated the average carbon emissions. It also evaluated the contribution of carbon emissions by energy sources.

• 한국환경과학회지
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• 제26권2호
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• pp.147-157
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• 2017

This study investigated the characteristics of variations in carbon dioxide concentration and air temperature with the vertical change of surface in a grassplot. Field observations were carried out at a grassplot in Gyeongnam Science High School, over four days in August and November, 2015. Continuous observation equipment (GMP343, VAISALA) was installed at the LP (0.1 m from the surface) and UP (1.1 m from the surface) points, and the carbon dioxide concentration and air temperature were measured simultaneously at 1-min intervals. To summarize the results of the observation, August had higher than average concentrations of carbon dioxide, while November showed average air temperatures. Moreover, the concentration of carbon dioxide was higher at the UP point, while the air temperature was higher at the LP point. The correlation coefficient of carbon dioxide concentration between the UP and LP points was 0.80 in August across all the four days, while it was higher in November at 0.58-0.95. The results of the regression analysis of carbon dioxide concentration with air temperature changes for both August and November showed a distinct change at the LP point (R2=0.36-0.76), as compared to the UP point (R2=0.1-0.57). Between the UP and LP points, the carbon dioxide concentration and air temperature regression analysis results indicated that an active exchange was taking place between the two points.

• Steel and Composite Structures
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• 제15권3호
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• pp.267-279
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• 2013

This article describes a simple and cost effective fabrication procedure by using hand lay-up technique that is employed for the manufacturing of thin-walled axi-symmetric composite shell structures with carbon, glass and hybrid woven fabric composite materials. The hand lay-up technique is very commonly used in aerospace and marine industries for making the complicated shell structures. A generic fabrication procedure is presented in this paper aimed at manufacture of plain Carbon Fabric Reinforced Plastic (CFRP) and Glass Fabric Reinforced Plastic (GFRP) shells using hand lay-up process. This paper delivers a technical breakthrough in fabrication of composite shell structures without any joints and wrinkling. The manufacture of stiffened CFRP shells, laminated CFRP shells and hybrid (carbon/glass/epoxy) composite shells which are valued by the aerospace industry for their high strength-to-weight ratio under axial loading have also been addressed in this paper. A fabrication process document which describes the major processing steps of the composite shell manufacturing process has been presented in this paper. A study of microstructure of the glass fabric/epoxy composite, carbon fabric/epoxy composite and hybrid carbon/glass/fabric epoxy composites using Scanning Electron Microscope (SEM) has been also carried out in this paper.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.542-546
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• 2004

Fully non-local Quasicontinuum method using sub-divided region with Hermite interpolation function is proposed for simulation of carbon nanotube. Tersoff-Brenner potential is adopted for interaction of bonded atoms and also van der Waals force for non-bonded interaction. Bending of single wall carbon nanotube with chirality (20,0) and 15nm length is simulated up to 90 degree. Bending of double wall carbon nanotube with chirality (20,0) and (12,0) is simulated up to 65 degree. Bending of four wall carbon nanotube is simulated up to 45 degree.

• International journal of advanced smart convergence
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• 제10권3호
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• pp.232-244
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• 2021

This study analyzed the changes in carbon monoxide, carbon dioxide, oxygen and visual distance by presence of sprinkler heads and their types in the event of a fire in an indoor gymnasium. Based on carbon monoxide and visual distance that affects human bodies enormously, first, if there is no sprinkler head, carbon monoxide will reach 0.4% within five seconds and visual distance rapidly shrank within five seconds. Seconds, in the event of standard sprinkler heads, carbon monoxide gradually increased from 30 seconds onwards and visual distance rapidly shrank after five seconds. Second, Third, if there are special sprinkler heads, carbon monoxide fluctuated after opening the head and visual distance became 5m or below from 15 seconds. Finally, in the event of early response sprinkler heads, carbon monoxide fluctuated up and down at 3 seconds due to falling water drops. Visual distance shrank up to 5m or below at 6 seconds. In the future, time for operation of each sprinkler head shall be analyzed.

• Carbon letters
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• 제11권3호
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• pp.184-191
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• 2010

Carbon nanotubes are unique tubular structures of nanometer diameter and large length/diameter ratio. The nanotubes may consist of one up to tens and hundreds of concentric shells of carbons with adjacent shells separation of ~0.34 nm. Multiwalled carbon nanotubes were synthesized by arc-discharge technique. MWCNTs were formed at the cathode deposit along with other carbonaceous materials like amorphous carbon, graphite etc. However, to get the best advantage of carbon nanotubes in various advanced applications, these undesired carbonaceous materials to be removed which is a challenging task. In the present study, various techniques were tried out for purifying MWCNTs such as physical filtration, chemical treatment and thermal annealing. SEM, FTIR, TGA and BET techniques were used to characterize the CNTs at various stages. Results shows that suitable chemical treatment followed by thermal annealing under controlled flow of oxygen gives the better route for purification of carbon nanotubes.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 D
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• pp.1432-1435
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• 1998

Influences of carbon black contents on the tracking resistance, tan $\delta$ and dielectric constant volume resistivity and dielectric strength of EPDM compounds before and after a exposure to UV radiation were investigated. Carbon black content up to 1.5 phr have a positive effect to improve the resistance to tracking and erosion, since carbon black diminish the leakage current. Results from the study reveal that both tan $\delta$ and dielectric constant volume resistivity and dielectric strength are unaffected by adding of carbon black up to 2.0 phr and carbon black have a significant effect to suppress the photo-degradation of EPDM compounds.

• 대한공업교육학회지
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• 제32권2호
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• pp.188-198
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• 2007

이 연구의 목적은 열처리 방법으로 탄소나노튜브에 백금나노 입자를 담지하는 것이다. 이 목적을 달성하기 위해서 염화백금산 수용액으로부터 hexachloro platinate(IV)를 탄소나노튜브에 흡착시킨 후 환원제를 사용하지 않고 질소분위기에서 $400^{\circ}C$로 열처리 하여 백금 나노입자를 담지 시켰다. 탄소나노튜브에 흡착된 hexachloro platinate(IV)의 함량은 UV-visible spectrophotometer를 사용하여 정량하였고, 탄소나노튜브에 담지된 백금 나노입자 존재와 분산을 확인하기 위해서 열중량분석, X-ray 회절분석, 투과전자현미경 관찰을 수행하였다. hexachloro platinate(IV)를 흡착시킨 탄소나노튜브를 환원제를 사용하지 않고 질소분위기에서 $400^{\circ}C$에서 열처리하면 2 nm 이하의 백금 나노입자가 균일하게 분포되었다. 한편, $800^{\circ}C$에서 열처리한 경우에는 백금입자들이 상호 응집현상이 발생하여 백금 입자의 크기가 커지고 분산이 균일하지 못했다. 따라서 hexachloro platinate(IV)를 탄소나노튜브에 흡착시킨 후 질소분위기에서 $400^{\circ}C$의 간단한 열처리를 통해서 백금 나노입자를 담지시킬 수 있었다.