• 한국정보통신학회논문지
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• 제19권1호
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• pp.156-162
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• 2015

본 연구에서는 비대칭 이중게이트 MOSFET의 산화막두께, 채널도핑농도 그리고 상하단 게이트 전압 등과 같은 소자 파라미터에 따른 전도중심 및 전자농도가 문턱전압이하 스윙에 미치는 영향을 분석하고자 한다. 비대칭 이중게이트 MOSFET는 대칭구조와 비교하면 상하단 게이트 산화막의 두께 및 게이트 전압을 각각 달리 설정할 수 있으므로 단채널효과를 제어할 수 있는 요소가 증가하는 장점을 가지고 있다. 그러므로 상하단 산화막두께 및 게이트 전압에 따른 전도중심 및 전자분포의 변화를 분석하여 심각한 단채널효과인 문턱전압이하 스윙 값의 저하 현상을 감소시킬 수 있는 최적의 조건을 구하고자 한다. 문턱전압이하 스윙의 해석학적 모델을 유도하기 위하여 포아송방정식을 이용하여 전위분포의 해석학적 모델을 구하였다. 결과적으로 소자 파라미터에 따라 전도중심 및 전자농도가 크게 변화하였으며 문턱전압이하 스윙은 상하단 전도중심 및 전자농도에 의하여 큰 영향을 받는 것을 알 수 있었다.

• Korean Chemical Engineering Research
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• 제43권6호
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• pp.662-667
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• 2005

HMCM-41 중간세공 물질(mesoporous material) 촉매를 사용하여 aryl methallyl ether로부터 의약품과 농약의 주요 중간체인 2,3-dihydrobenzofuran 유도체를 합성하였다. 산점 농도가 촉매 활성에 미치는 영향을 비교하기 위하여 Si/Al 몰비가 40과 50으로 다른 촉매를 제조하였으며, aryl methallyl ether에 다양한 치환기를 도입하여 벤젠 고리의 전자 밀도가 전환율과 수율에 미치는 효과를 조사하였다. 산점이 많아질수록 전환율은 높아졌으나, 2,3-dihydorbenzofuran 유도체의 수율과 직접 연관짓기는 어려웠다. 전자공여기의 치환으로 벤젠 고리의 전자 밀도가 높아지면 claisen 자리 옮김 반응이 빨라져서 2,3-dihydrobenzofuran 유도체가 많이 생성되었다. 반면, 전자흡인기가 치환되어 벤젠 고리의 전자 밀도가 낮아지면 산 촉매에 의해 aryl methallyl ether 분해 반응이 촉진되어 2,3-dihydrobenzofuran 유도체 대신 phenol 유도체가 생성되었다.

• 한국응용과학기술학회지
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• 제33권4호
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• pp.693-697
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• 2016

본 연구는 추출물 농도에 따른 생리활성물질의 용출량을 측정하기 위해 전자공여능과 총 폴리페놀 함량을 측정한 결과이다. 전자공여능은 추출물의 첨가 농도가 15%인 경우는 21.81%로 나타났고, 35% 농도에서 40.45%로 가장 높았다. 한약재의 첨가 농도가 증가함에 따라 전자공여능은 유의적으로 증가하였다(p<0.05). 가장 높은 35% 첨가 농도에서의 40.45% 공여능은 이보다 더 낮았으므로 전자공여능은 미약한 것으로 생각된다. 총 폴리페놀함량은 한방약술 15%에서는 $113.89{\pm}1.79{\mu}g\;GAE/m{\ell}$로 나타났고, 한방약술 35% 에서는 $274.24{\pm}0.71{\mu}g\;GAE/m{\ell}$로 나타나서 첨가물의 농도 증가에 따라 총 폴리페놀의 함량도 유의적으로 증가하였다(p<0.05). 추출물 농도가 30%에서 총 폴리페놀 함량의 증가 폭이 $61.75{\mu}g\;GAE/m{\ell}$로 가장 높았다.

• Journal of Magnetics
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• 제20권3호
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• pp.241-245
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• 2015

A study on the preparation of nickel oxide nanoparticles using electron beam irradiation is described. Nickel nanoparticles were synthesized with nickel chloride hexahydrate as a metal precursor and different sodium hydroxide concentrations using electron beam irradiation. The effects of sodium hydroxide concentration and electron beam absorbed doses were investigated. The samples were synthesized at different sodium hydroxide concentrations and with absorbed doses of 100 to 500 kGy at room temperature. Synthesized nanoparticles were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) and a vibrating sample magnetometer (VSM). The nanoparticle morphologies seemed to be non-spherical and aggregated. The 1:1 molar ratio of nickel chloride hexahydrate and sodium hydroxide showed a higher purity and saturation magnetization value of 13.0 emu/g. The electron beam absorbed dose was increased with increasing nickel nanoparticle nucleation.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 추계학술발표회
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• pp.391-394
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• 2003

The applicability of in situ microbial filter or biobarrier technology for the remediation of soil and groundwater contaminated with chlorinated solvents was investigated. The efficiency and rates of reductive dechlorination of chlorinated solvents are known to be highly dependent on hydrogen concentration. In this study, the effect of electron donors on the reductive dechlorination of PCE was investigated using vermicompost (worm casting) and peat as permeable reactive barrier medium The effect of organic acids (lactate, butyrate and benzoate), yeast extract and vitamin $B_{l2}$ on the reductive dechlorination was investigated. Compared to the control (no electron donor added), addition of electron donors stimulated the dechlorinated rate. Among the electron donor treatments, lactate/benzoate amendment exhibited the highest dechlorination rate. Since vermicompost and peat are inexpensive and biodegradable and have high sorption capacity, they could be successfully used as biobarrier media, especially when electron donors (for example, lactate/benzoate) are added.d.

• 한국대기환경학회지
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• 제17권1호
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• pp.97-104
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• 2001

Decomposition of trichloroethlyene(TCE) in electron beam irradiation was examined on order to obtain information on the treatment of VOC in air. Air containing vaporized TCE has been studied in a flow reactor with different reaction environments, at various initial TCE concentration and in the presence and absence of water vapor. Maximum decomposition was observed in oxygen reaction environment and the degree of decomposition was about 99% at 20kGy for 2,000ppm initial TCE. The concentration of TCE exponentially decreased with dose in air and pure oxygen. The effect of water vapor on TCE decomposition efficiency was examined. The decomposition rate of TCE in the presence of water vapor (5,600 ppm) was approximately 10% higher than that in the absence of water vapor. Dichloroacetic acid, dichloroacethyl chloride and dichloroethyl ester acid were identified as primary products of this reaction adn were decomposed and oxidized to yield CO and $CO_2$. Perchloroethylene, hexachloroethane, chloroform and carbon tetrachloride were also observed as highly chlorinat-ed by products.

• 한국세라믹학회지
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• 제41권2호
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• pp.102-105
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• 2004

ZnO-In$_2$O$_3$ films were fabricated on Corning 1737 glass substrate by an electron beam evaporation technique and their characteristics were investigated. The composition of ZnO-In$_2$O$_3$ films had a marked effect on the electrical properties of the films. The ZnO-In$_2$O$_3$ films showed superior transparent-conducting characteristics with increase of Zn content. The resistivity and carrier concentration of the film having Zn content of 45 at% are 4.45${\times}$10$^{-3}$ cm and 3.1${\times}$10$^{19}$ cm$^{-3}$ , respectively. Also, the transmittance was higher than 80% throughout the visible range. The average roughness of the film was 14.6 $\AA$ in terms of root mean square.

• 한국세라믹학회지
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• 제28권3호
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• pp.197-204
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• 1991

The photoelectrochemical conversion in SnO2 films deposited by spray pyrolysis using SnCl4-alcohol solution and N2 gas has been studied. The photocurrent increases with increasing deposition temperature up to 40$0^{\circ}C$ and then decreases, and the electron affinity decreases as the deposition temperature increases to 40$0^{\circ}C$. As the concentration of the spray solution increases, the photocurrent reaches a maximum value at the concentration of 0.05M, and the electron affinity is consistent. As the thickness of the film increases, the photocurrent increases with a maximum value at the thickness of 4600$\AA$, and electron affinity does not change.

• 한국염색가공학회지
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• 제15권3호
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• pp.154-160
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• 2003

Polypropylene nonwoven fabrics were grafted with acrylic acid by a preirradiation method by using electron beam accelerator. The effect of irradiation dose, storage time, concentration of acrylic acid, reaction temperature, reaction time and Mohr's salt concentration on the degree of grafting were investigated in detail. The grafted Polypropylene nonwoven fabrics were characterized using IR spectroscopy and SEM. The results showed that the degree of grafting increased with increasing absorbed dose and the Mohr's salt in the acrylic acid solution promoted grafting efficiency.

• Bulletin of the Korean Chemical Society
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• 제6권5호
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• pp.304-308
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• 1985

Morphological structure of tin oxide thin films was examined by transmission electron microscopy. TEM samples were prepared by chemical etching in hydrogen fluoride solution: firstly floating for 2-3 minutes in acid solution, then suspending on water found to be useful for the preparation of TEM samples. Electron micrographs showed the size of grains of the tin oxide crystal was dependent upon the temperature of the film preparation. Dopant concentration and heating time also influence the grain size. The resistivity of tin oxide material was explained by grain size and grain boundaries in a limited temperature and dopant concentration ranges.