• Carbon letters
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• 제18권
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• pp.11-17
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• 2016

Monolithic carbon foams with hierarchical porosity were prepared from polyurethane templates and resol precursors. Mesoporosity was achieved through the use of soft templating with surfactant Pluronic F127, and macroporosity from the polyurethane foams was retained. Conditions to obtain high porosity materials were optimized. The best materials have high specific surface areas (380 and 582 m² g^-1, respectively) and high electrical conductivity, which make them good candidates for supports in sensors. These materials showed an almost linear dependence between the potential and the pH of aqueous solutions.

• 한국환경과학회지
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• 제13권3호
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• pp.319-325
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• 2004

An experimental study on the preparation of monolithic porous polymers by environmentally friend process in supercritical carbon dioxide has been carried out. Polymerization mixture composed of a cross-linking monomer, initiator and functional co-polymer was charged in the reactor with sapphire window. After the system was purged with a flow of $CO_2$ for 15 min, the reactor was pressurized with liquid $CO_2$ up to 100 bars. The reactor was isolated from and placed back to the system via quick connector for shaking until the mixture had become fully homogeneous. The reactor was then heated and pressurized to the required reaction conditions and left overnight. After cooling and $CO_2$ evacuation, the polymer was removed from the reactor as dry, white, continuous monoliths. The effect of experimental conditions on the physical properties of porous polymer was systematically examined, and it was found that monomer content had a major effect on the physical properties of the polymers.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1996년도 추계학술대회 논문
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• pp.180-186
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• 1996

Using carbon steel or ceramic as a shaft material of monolithic and slited insert ring clamped on it. The fitting strengths of the sgrink fitted assemblies measured from room temperature to 30$0^{\circ}C$ and following conclusions were obtained as results of this investigation. 1) The fitting condition under which the shrink fitted assemble was stronger than that using simple fit in high temperature. 2) When both material of the 30mm-diameter shaft and 55mm-diameter boss are SM45C the clamping torque is increased 2.7times as the interference increases 3 times from 20${\mu}{\textrm}{m}$ at the contact length of 6mm monolithic fit. 3) When only the material of boss is changed to STS 304 the clamping torque is increased at the rate of 37.3N.m per 1mm increase of the contact length at the interference of 50${\mu}{\textrm}{m}$ monolithic fit.

• Bulletin of the Korean Chemical Society
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• 제32권12호
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• pp.4275-4280
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• 2011

Present study describes the optimization of disk type sorptive extraction using monolithic material (Mono Trap) for the analysis of volatile aroma compounds from Lantana camara L. in combination with gas chromatography/mass spectrometry (GC/MS). Monolithic material sorptive extraction (MMSE) is a new sampling technique using a monolithic hybrid adsorptive disk (O.D. 10 mm, 1 mm thickness) made of high purity silica and activated carbon having a large surface area chemically bonded with octadecyl silane (ODS). The experimental parameters that may influence the MMSE efficiency have been optimized. Linearity, accuracy, precision and detection limits were evaluated to assess the performance of the proposed method. The method was validated with real plant samples of Lantana camara L. Twenty eight compounds including the main representative compounds of ${\alpha}$-curcumene and ${\beta}$-caryophyllene were found in analyzed samples. Results proved that proposed method could be used as a good alternative for the analysis for such volatile aroma compounds in plant samples.

• Korean Chemical Engineering Research
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• 제43권1호
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• pp.21-26
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• 2005

초임계 이산화탄소를 이용하여 다공성 고분자 모노리스를 제조하는 실험적 연구를 행하여, 단량체의 종류와 중합반응 조건들이 생성되는 고분자 모노리스의 물성에 미치는 영향을 실험적으로 조사하였다. 중합반응은 반응이 진행되는 동안 반응물의 상변화를 관찰할 수 있도록 사파이어 창을 부착한 고압 반응기 내에서 진행되었으며, 단량체의 농도가 매우 낮은 경우를 제외하고는 반응기 내부형태와 동일한 형상의 건조하고 다공성인 고분자 모노리스를 얻었을 수 있었다. 생성되는 고분자 모노리스의 비 표면적은 반응혼합물 중의 단량체 농도와 중합반응 압력에 따라 증가하였으며, 기계적 강도는 경도 보강제 MMA를 첨가하여 증대시킬 수 있었다.

• Carbon letters
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• 제1권1호
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• pp.12-16
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• 2000

Carbon fiber was reacted with gaseous silicon monoxide which is produced from pack-powder mixture at elevated temperature. As a result of the reaction, two kinds of SiC fiber were obtained. The first one was SiC fibers which were converted from carbon fiber. The fiber is constituted with polycrystal like fine grains or monolithic crystals that have a size from sub-micron to $10\;{\mu}m$. Their size depends on the temperature during the conversion reaction. The second one was ultra-fine SiC fibers that were found on the surface of the converted SiC fibers. The ultra-fine fibers have diameters from 0.08 to $0.2\;{\mu}m$ and their aspect ratio were larger than 100. The chemical composit ion of the ultra-fine fibers was analyzed using an Auger electron spectroscopy. In result, the fibers consist of 51% silicon, 38% carbon and 11% oxygen by weight.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2012년도 춘계학술발표대회
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• pp.68.2-68.2
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• 2012

We present a scheme for monolithically integrating aligned arrays of single walled carbon nanotubes (SWNTs) with sheets of graphene, for use in electronic devices. Here, the graphene and arrays of SWNTs are formed separately, using chemical vapor deposition techniques onto different, optimized growth substrates. Techniques of transfer printing provide a route to integration, yielding two terminal devices and transistors in which patterned structures of graphene form the electrodes and the SWNTs arrays serve as the semiconductor. Electrical testing and analysis reveal the properties of optically transparent transistors that use this design, thereby giving insights into the nature of contacts between graphene and SWNTs.

• 한국세라믹학회지
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• 제21권2호
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• pp.127-134
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• 1984

Basic research on the formation of monolithic glasses from metal alkoxide has been done concerning gelling of silicon alkoxides and dehydration of those gells. The felling time were increased with increasing of Carbon number of alkyl radical of alkoxide and am-ount of water and the lower pH value of water. Large portions of water and organic materials were rem-oved below 25$0^{\circ}C$ and shrinkage of glass took place above 80$0^{\circ}C$ Therefore heating up to 25$0^{\circ}C$ and above 75$0^{\circ}C$ must be done gradually with rate of 0.5$^{\circ}C$/min.

• 분석과학
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• 제24권6호
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• pp.421-428
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• 2011

본 연구에서는 시료상층부 원판 형태 흡탈착 추출법(HS-MMSE)을 개발하여 검증하고 바닐라 향수의 휘발성 아로마 성분들의 기체 크로마토그래피-질량 분석법에 적용하였다. HS-MMSE 방법은 실리카에 octadecyl silane (ODS)과 활성탄을 결합하여 만든 단일 다공성 물질(monolithic material, MonoTrap)을 흡착제로 이용한다. MonoTrap은 시료상층부에서 아로마 성분들을 흡착하고 100 ${\mu}L$ 소량의 용매로 추출한다. HS-MMSE를 이용하여 바닐라 향수로부터 12개의 성분들을 성공적으로 분석하였다. 그 중 benzyl acetate, linalyl acetate, vanillin, ethyl vanillin을 이용하여 추출 효율에 영향을 주는 파라미터들에 대한 실험을 통해 추출 조건을 최적화하였다. 또한, 대상 물질들에 대한 분석 방법의 검증 실험을 진행하였다. 그 결과, 검출한계, 정량한계는 각각 8.35~13.76 ng, 27.82~45.88 ng 범위였고 $r^2$값이 0.9888 이상인 우수한 직선성과 양호한 회수율 및 재현성을 얻었다. 이러한 결과들을 바탕으로 원판 형태 MonoTrap을 이용한 HS-MMSE 방법은 바닐라 향수의 휘발성 아로마 성분들을 분석하는데 효과적인 방법임을 확인하였다.

• 대한금속재료학회지
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• 제47권1호
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• pp.50-58
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• 2009

In this study, alumina matrix composites reinforced with carbon nanotubes (CNTs) were fabricated by ultrasonic dispersion, ball milling, mixing, compaction, and sintering processes, and their relative density, electrical resistance, hardness, flexure strength, and fracture toughness were evaluated. 0~3 vol.% of CNTs were relatively homogeneously dispersed in the composites in spite of the existence of some pores. The three-point bending test results indicated that the flexure strength increased with increasing volume fraction of CNTs, and reached the maximum when the CNT fraction was 1.5 vol.%. The fracture toughness increased as the CNT fraction increased, and the fracture toughness of the composite containing 3 vol.% of CNTs was higher by 40% than that of the monolithic alumina. According to observation of the crack propagation path after the indentation fracture test, a new toughening mechanism of grain interface bridging-induced CNT bridging was suggested to explain the improvement of fracture toughness in the alumina matrix composites reinforced with CNTs.