• 한국입자에어로졸학회지
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• 제6권2호
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• pp.61-67
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• 2010

In this paper, we describe a new method to form polymer thin films, in which carbon nanotubes (CNTs) are homogeneously distributed so that they can strengthen the mechanical property of resulting polymer film. To do so, we first homogeneously mixed CNTs with polymer in a DMF solvent. With the assistance of ultrasonic nebulizer, the polymer/CNT solution was then aerosolized into micro-sized droplets and finally turned into solidified polymer/CNT composite particles by gas-phase drying process. As the results of SEM and TEM analysis, CNTs were found to be homogeneously immobilized in the polymer matrix particles due to rapid drying process in the gas phase. For comparison purpose, (i) the polymer/CNTs composite particles prepared by aerosol processing method and (ii) polymer/CNTs sheets prepared by simple solution-evaporation method were employed to form polymer/CNTs composite thin films using a hot press. As the result, the aerosol processing of composite particles was found to be a much more effective method to form homogeneously distributed-CNTs in the polymer matrix thin film.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.200-203
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• 2007

Parametric investigation of the polyol process for the preparation of carbon supported Pt nano particles as catalysts for fuel cells was carried out. It was found that the concentration of glycolate anion, which is a function of pH, plays an important role in controlling Pt particle size and loading on carbon. It was observed that Pt loading decreased with increasing alkalinity of the solution. As evidenced by zeta potential measurement, this was mainly due to poor adsorption or repulsive forces between the metal colloids and the supports. In order to modify the conventional polyol process, the effect of the gas purging conditions on the characteristics of Pt/C was examined. By the optimization of the gas environment during the reaction, it was possible to obtain high loading of 39.5wt% with a 2.8 nm size of Pt particle. From the single cell test, it was found that operating in ambient $O_{2}$ at 70oC can deliver high performance of more than 0.6 V at 1.44 A $cm^{-2}$.

• 한국환경과학회지
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• 제21권5호
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• pp.623-631
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• 2012

The adsorption behavior of Eosin Y on activated carbon (AC) in batch system was investigated. The adsorption isotherm could be well fitted by the Langmuir adsorption equation. The kinetics of adsorption followed the pseudo-second-order model. The temperature variation was used to evaluate the values of free energy (${\Delta}G^{\circ}$), enthalpy (${\Delta}H^{\circ}$) and entropy (${\Delta}S^{\circ}$). The positive value of enthalpy change ${\Delta}H^{\circ}$ for the process confirms the endothermic nature of the process and more favourable at higher temperature, the positive entropy of adsorption ${\Delta}S^{\circ}$ reflects the affinity of the AC material toward Eosin Y and the negative free energy values ${\Delta}G^{\circ}$ indicate that the adsorption process is spontaneous. With the increase of the amount of AC, removal efficiency of Eosin Y was increased, but adsorption capacity was decreased. And adsorption capacity was increased with the decrease of particle size. With the increase of the amount of AC, removal efficiency of Eosin Y was increased, but adsorption capacity was decreased. And adsorption capacity was increased with the decrease of particle size.

• KSBB Journal
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• 제18권3호
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• pp.243-247
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• 2003

커들란과 활성탄의 조성을 몇 가지로 나누어서 실험한 결과 커들란 30 g/L과 활성탄 6 g/L의 비로 제조하여 Autoclave ($121^{\circ}C$, 1 atm, 15 min)에서 가열한 담체의 물성이 다공성 특성 및 세포의 고정화 측면에서 우수함을 보였다. 충전층 반응기를 설치하여 담체를 고정시킨 후 미생물 부착능력을 실험한 결과, 철 산화 세균에 의하여 시간이 증가할수록 철 산화 속도가 빨라지고, 이 과정을 주사전자현미경으로 촬영한 결과 시간이 증가할수록 담체에 부착되는 미생물의 농도가 증가함을 확인할 수 있었다. 그리고 본 실험에서 사용된 담체는 환경 친화적인 고분자로 2차적으로 발생할 수 있는 환경문제를 해결 할 수 있으며 기존의 담체에 비교하여 비표면적이 넓고, 인체에 해가 없는 생물고분자 담체이므로 식품용도의 흡착제 등으로도 유용하게 사용될 수 있다.

• 한국화재소방학회논문지
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• 제31권4호
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• pp.7-11
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• 2017

각종 화재, 폭발, 누출, 테러 사고 시 발생되는 유해가스로부터 작업자나 소방대원들의 안전을 확보하고 원활한 구조활동을 위하여 입자형 활성탄을 여과재로 사용하는 특수 방독면의 필요성이 크게 증가하고 있다. 본 연구에서는 CFD 유동해석을 통하여 활성탄 정화통에 대한 압력손실 특성을 규명하였으며, 해석 결과 호흡유량에 대한 압력손실은 유속이 빠를수록, 여과재의 입자가 작을수록, 공극률이 작을수록 커지지만, 특정 조건 이상에서는 그 변화가 매우 크게 나타나 활성탄 여과재의 선택 시 이를 충분히 고려하여야 하는 것으로 분석되었다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제47권4호
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• pp.315-320
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• 2021

Carbon-ion radiotherapy (CIRT) is on the rise as a treatment choice for malignant tumor. Compared to conventional radiotherapy, particle beams have different physical and biological properties. Particle beam provides a low entry dose, deposits most of the energy at the endpoint of the flight path, and forms an asymptotic dose peak (the "Bragg peak"). Compared to protons, carbon with its larger mass decreases beam scattering, resulting in a sharper dose distribution border. We report a 50-year-old male who underwent CIRT without surgical resection on osteosarcoma of the mandible. After CIRT, the patient's pain was gone, and the malignant mass remained stable with accompanying necrosis. Nine months later, however, magnetic resonance imaging demonstrated progression of the left mandibular osteosarcoma with pulmonary metastases. After multidisciplinary discussion, concurrent chemoradiotherapy was conducted. While necrotic bone segments came out of the mandible during subsequent periodic outpatient visits, the tumor itself was stable. Thirty months after his first visit and diagnosis, the patient is waiting for chemotherapy. Although CIRT is superior in treating radioresistant hypoxic disease, CIRT is in its infancy, so care must be taken for its indications and complications.

• 한국전기전자재료학회논문지
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• 제36권2호
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• pp.164-169
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• 2023

Nano Pt particles were dispersed on carbon-based supports by a polyol process for a catalyst application in a polymer electrolyte fuel cell. We tried to optimize the effect of pH on the electrostatic forces between the support and the Pt colloids. We investigated the relationship among the surface charges on the carbon support, the solution pH, and the concentration of a glycolate, and the Pt particle size. The produced catalyst with nano Pt particles on the support was evaluated by the long-term cyclic voltammetry (CV) performance test and compared with the results from a commercial catalyst. Our experimental results reveal that the pH-control can modify the particle size distribution and the dispersion of the nano Pt particles. This resulted in a cost-effective method for the synthesis of highly Pt loaded Pt/C catalysts for fuel cells better than a commercial catalyst system.

• 한국세라믹학회지
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• 제36권5호
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• pp.504-512
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• 1999

The high-quality carbon nanofibers were prepared by chemical vapor deposition of gas mixtures of CO-H2 and C3H8-H2 over Fe-Cu and Ni-Cu bimetallic catalysts. The yield and structure of carbon nanofiber produced were altered by the change of catalyst composition and reaction temperature. The high yields were obtained around 500$^{\circ}C$ with e-Cu catalyst and around 700-750$^{\circ}C$ with Ni-Cu catalyst and the relatively higher yields were obtained with the bimetallic catalyst containing 50-90% of Ni and Fe respectively in comparison with the pure metals. The carbon nanofibers produced over the Fe-Cu catalyst at around 500$^{\circ}C$ with the maximum yields had the highest surface ares of 160-200 m2/g around 650$^{\circ}C$ which was slightly lower than the temperature for maximum yields. In order to examine the characteristics of carbon nanofibers as catalyst support Ni and Co metals were supporte on the carbon nanofibers and CO hydrogenation reaction was performed with the catalysts. The particle size distribution of Ni and Co supported over the carbon nanofibers were 6-15 nm and the CO hydrogenation reaction rate with the carbon-nanofiber supported catalysts was much higher than that over the other supports.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2004년도 추계학술대회 논문집
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• pp.501-502
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• 2004

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2005년도 추계학술발표회
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• pp.306-307
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• 2005