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      • KCI등재

        오존 처리된 페놀계 활성탄소섬유의 표면 특성

        고경열,양범호,유승곤 한국화학공학회 2003 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.41 No.3

        액상에서의 오존 산화 반응에 의해 활성탄소섬유 표면 산소의 함량은 17.0wt%에서 22.4wt%로 증가하였고, 수소의 함량은 1.9wt%에서 2.7wt%로 증가하였다. 오존 산화 개시제를 달리하여 처리하면 활성탄소섬유에 생성되는 관능기들과 총산도 값을 조절할 수 있었다. 오존 처리되지 않은 활성탄소섬유의 총산도값은 0.631 meq./g인데 비하여, 1M NaOH 수용액을 개시제로 증가하였고, 특히 phenol그룹이 크게 증가하였다. NaOH로 처리하면 phenol그룹만 증가하였고, H_2O_2로 처리하면 phenol 그룹이 많이, carboxyl그룹이 약간 증가하였다. The oxygen and the hydrogen contents of activated carbon fibers increased from 17.0 wt% and 1.9 wt% to 22.4 wt% and 2.7 wt% by oxidation with ozone in liquid phase. The amount of functional groups and total acidity could be controlled with initiators of ozone decomposition reactions. The total acidity of ACF ozone treated ACF was 0.63 l meq./g, and particularly the phenolic group increased. The phenolic group only was developed when ACF was treated in NaOH solution, large amount of phenolic group and some carboxylic group only was developed when ACF was treated in NaOH solution, large amount of phenolic group and some carboxylic group were developed when ACF was treated in H_2O_2 solution.

      • 곁사슬형 Polyethylene Glycol을 가진 Adenosine Deaminase 결합체의 생화학적 특성

        안치운,이범종,김동규 인제대학교 1996 仁濟論叢 Vol.12 No.2

        Calf adenosine deaminase(ADA) was modified with pendant-type polyethylene glyco1(PEG) using cyanuric chloride as a coupler. Attachment of PEG to the enzyme alters the kinetic profile of the enzyme in that a decrease in the Km for adenosine. The Km value of the ADA and PEG-ADA10 were 30 μM, 25 μM against adenosine, respectively. But the PEG-ADA20 exhibited reasonable retention of catalytic activity with a increased Km, it was 50 μM against adenosine. Thermal inactivation at temperature above optima was essentially the same for the native and modified enzyme. PEG appears to have no effect on stabilizing to high temperature. This suggests that PEG attachment causes some destabilization of the adenosine deaminase structure. The electrophoretic mobility in polyacrylamide gels of PEG-ADA was severely reduced as compared to the native enzyme. Unmodified proteins show single band, whereas the modified enzyme forms a number of bands throughtout the gels. The decreased electrophoretic mobility of PEG-ADA may be due to a charge-shielding effect of the hydrophilic PEG shell surrounding the enzyme. In addition, the increased size of the adducts formed may serve to retard migration in the polyacrylamide gels. The present results show that the biochemical properties of adenosine deaminase were altered after chemical modification with PEG.

      • 2-헵타데실-2-옥사졸린의 공기-물 계면에서의 일분자막 및 LB막 특성

        황선경,이범종 인제대학교 기초과학 연구소 1999 자연과학 Vol.3 No.-

        2-헵타데실-2-옥사졸린(C17-OXZ)양친매성 분자의 공기-물 계면에서의 개환 반응과 Langmuir-Blodgett(LB)막의 가교화에 대해 연구하였다. C17-OXZ는 스테아르산과 2-아미노에탄올의 탈수 및 고리화 반응에 의해 합성되었다. 일분자막의 특성은 표면압력-면적(π-A)등온선으로 확인하였다. 하층액이 산성일 때 또는 폴리알릴아민을 포함하고 있을 때 일분자막이 더욱 팽창하였다. 그러나, 알칼리 하층액에서는 순수인 경우에 비하여 π-A등온선상에 주목할 만한 변화가 관찰되지 않았다. 폴리아크릴산을 포함하는 경우에서는 더욱 팽창된 일분자막을 형성하였고 표면압력의 자발적인 증가가 발견되었다. 일분자막의 상변화는 Brewster 각 현미경(BAM)에 의하여 관찰되었다. 일분자막들은 플루오르화 칼슘기판에 누적되었고 FT-IR 분광법으로 분자구조를 결정하였다. 그 결과 옥사졸린의 개환 중합보다는 이미노 이중결합의 가수분해 반응이 우세함을 확인하였다. LB막의 안정성은 다공성 기판 위로의 누적형태를 주사 전자 현미경으로 관찰함으로써 간접적으로 평가하였다. 하층액에 폴리아크릴산을 포함하는 경우가 가장 안정된 LB막을 형성하였다. The network structures of monolayers are important for molecularly-thin films such as the LB film in order to improve the intrinsic fragility and to make their technological applications possible. In this study, we investigated the ring-opening reaction of 2-heptadecyl-2-ox-azoline(C17-OXZ) at the air-water interface and its formation of network LB films. The amphiphile C17-OXZ was synthesized via dehydration and cyclization of stearic acid with 2-am-inoethanol. Monolayer behaviors were studied at the air-water interface by measuring the surface pressure-area(π-A)isotherms. When the subphase became acidic or contained poly(allylamine), the monolayers showed more expanded phases. However, any noticeable change of the π-A isotherm was not observed in alkaline subphase compared with that of pure water subphase. When poly(acrylic acid)was dissolved in the subphase, the π-A isotherm revealed expanded monolayer and a spontaneous increase of surface presssure was found. Phase changes of the monolayers were observed by Brewster angle microscopy(BAM). The monolayers were transferred onto calcium fluoride substrates and the molecular structures were determined by the FT-IR spectroscopy. However, the competitive advantage was favored to hydrolytic reaction of imino double bond rather than the ring-opening polymerization expected from the imino nitrogn on oxazoline ring. The stability of the network film was indirectly evaluated by the SEM observation of the film morphology covered over the porous substrate. The most stable LB film was produced from the subphase containing poly(acrylic acid)

      • 고분자 이미다졸-금속 착제 LB막의 선책적 기체 투과성

        김병주,이범종 인제대학교기초과학연구소 1999 자연과학 Vol.3 No.-

        이미다졸-금속 이온구조를 갖는 고분자 Langmuir-Blodgett(LB)막을 다공성 막 필터 위에 제조하여 산소와 질소의 투과성을 이들의 캐스트 막과 비교하여 검토하였다. 양친매성 고분자 폴리(N-(2-(4-이미다졸일)에틸)말레이미드·alt-1-옥타데센)(IM-O)는 폴리(무수말레산-alt-1-옥타데센)과 히스타민의 반응으로 합성되었다. IM-O는 순수한 물 또는 금속 이온 (철(Ⅲ)과 코발트(Ⅱ)이온)하층액 위에서의 40 mN/m의 표면압력에서도 안정한 일분자막을 유지하였다. 이 일분자막은 30 mN/m의 표면 압력에서 FP-010 막 필터 위에 Y형태로 누적되었다. 이 다중막의 구조는 FT-IR을 통하여 확인하였다. LB막의 균일성과 안정성은 SEM 관찰을 통하여 간접적으로 평가하였고, 산소와 질소의 투과도는 감압법을 이용하여 측정하였다. 본 LB막들의 기체 선택성은 산소보다 질소가 약간 높게 나타났으며, 두 기체에 대하여 모두 고투과성을 나타냈다. 이들 고분자-금속 착체의 캐스트 막을 제조하여 기체 투과도를 측정한 결과 질소에 대한 선택성은 변함이 없었다. The permeability of oxygen and nitrogen was investigated from the polymeric LB films containing imidazole-metal ion complexes and compared with its corresponding cast films on porous membrane filters. The amphiphilic polymer, poly(N-(2-(4-imidazolyl)ethyl)-maleimide-alt-1-octadecene)(IM-O), was synthesized by reaction of poly(maleic anhydride-alt-1-octadecene)with histamine. Chloroform solutions of IM-O were spread on pure water and aqueous metal ions(iron(Ⅲ) and cobalt(Ⅱ)ions) and the monolayers showed high stability up to 40 mN/m against surface pressure. The monolyers of polyion-complexed polymers at the air-water interface can be transferred onto solid substrates such as a porous fluorocarbon membrane filter(FP-010) and a CaF2 plate. The Y-type deposition was found at a surface pressure of 30 mN/m. The molecular structures of LB films were investigated by means of FT-IR spectroscopy. The mechanical stability and uniformity of the LB films on FP-010 membranes were indirectly evidenced by SEM observation of the surface morphology of FP-010 membranes were indirectly evidenced by SEM observation of the surface morphology of FP-010 covered with the LB films. The permeability of oxygen and nitrogen was measured with the pressure method. The LB films showed more or less higher selectivity toward nitrogen, and high permeability was found to both the oxygen and nitrogen. The cast films of the corresponding polymer-metal complexes also showed preference to nitrogen in selectivity.

      • KCI등재

        Electrical Properties and Fabrication of G3-16[TPY-Ru-TPY] Dendrimer Thin Films

        Sang-Burm Jung,Burm-Jong Lee,Chungkyun Kim,Young-Soo Kwon 한국물리학회 2004 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.44 No.1

        Dendrimers have been well known as promising macromolecules for building an organized nanostructure, whose periphery can be terminated by various functionalities. In this study, we attempted to fabricate ultra-thin dendrimer lms containing 16[TPY-Ru-TPY] end functional groups. The samples for the determination of the electrical properties were fabricated by using the Langmuir- Blodgett (LB) method. We investigated the surface activity at the air-water interface as well as the electrical properties for monolayers of the G3-16[TPY-Ru-TPY] dendrimer. The -A isotherms of the dendrimers showed that stable condensed lms were formed at the air-water interface. Also, we studied the electrical properties of ultra-thin dendrimer LB lms by using the I-V characteristics and Schottky plots with a metal/insulator/metal (MIM) structure.

      • SCOPUSKCI등재
      • SCIESCOPUSKCI등재

        Wide Band-gap FETs for High Power Amplifiers

        Burm, Jin-Wook,Kim, Jae-Kwon The Institute of Electronics and Information Engin 2006 Journal of semiconductor technology and science Vol.6 No.3

        Wide band-gap semiconductor electron devices have made great progresses to produce very high power amplifiers for various wireless standards. The advantages of wide band-gap electronic devices and their progresses are summarized in this paper.

      • KCI등재

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