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        검색결과 346

        81.
        2018.12 구독 인증기관 무료, 개인회원 유료
        Rock bream iridovirus (RBIV) is a megalocytivirus widely infected in various fish species in Korea, causing symptoms of acute inflammation and enlargement of spleen. In our previous study, RBIV induced the initial upregulation but later down-regulation of proinflammatory cytokines and IFN1 gene expression. Signal transducers and activators of transcriptions (STAT) are transcription factors involved in the regulation of immune genes including IFNs. This study was conducted to analyse the expression of STAT2. The expressional study of STAT2 gene was performed in head kidney and spleen upon RBIV infection and immune stimulants like LPS or poly I:C in vitro. Consequently, STAT2 gene expression pattern was different in head kidney and spleen as it was significantly up-regulated by LPS from 4 h to 8 h but down-regulated at 24 h while up-regulated by poly I:C at 8 h in head kidney while, in spleen, STAT2 gene expression was down regulated by LPS but significantly up-regulated by poly I:C. Upon RBIV stimulation, STAT2 gene expression was significantly down-regulated by high dose RBIV at 4 h but up-regulated at 8 h and 24 h in head kidney. In spleen cells, it was up-regulated by medium dose RBIV at 4 h and by high dose RBIV at 4 h and 8 h but down regulated later then. In vivo, STAT2 gene expression was not significantly affected by RBIV infection while significant up-regulated by vaccination at day 7 post-vaccination, indicating STAT2 gene can be involved in adaptive immune response in rock bream.
        4,000원
        82.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 강유전성 고분자를 이용하여 제작된 100 nm 이하 두께를 가지는 박막형 커페시터의 측정 주파수에 따른 분극 반전 특성을 측정, 분석하였다. 고정된 박막 두께에 대해, 인가되는 최고 전기장의 세기가 증가할수록 더 높은 항전계에서 분극 반전이 발생되었다. 고정된 최고 전기장에 대해, 박막의 두께에 무관하게 같은 항전계에서 분극 반전이 발생되었다. 모든 측정에서 로그스케일 전기장 및 로그스케일 주파수의 관계에서 약 0.12 ± 0.01의 비례 상수를 보였다. 결과적으로, 강유전체 고분자 커페시터가 40 nm 두께까지는 size effect 없이 일정한 분극 반전 특성을 보였다. 본 연구는 저전압 동작 고분자 메모리 소자의 동작 예측에 유용할 것이므로 저전압에서 동작 가능한 고분자 메모리 소자의 가능성을 보여준다.
        4,000원
        83.
        2018.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We investigate the effect of light intensity and wavelength of a solar cell device using photoconductive atomic force microscopy(PC-AFM). A POCl3 diffusion doping process is used to produce a p-n junction solar cell device based on a poly- Si wafer, and the electrical properties of prepared solar cells are measured using a solar cell simulator system. The measured open circuit voltage(Voc) is 0.59 V and the short circuit current(Isc) is 48.5 mA. Moreover, the values of the fill factors and efficiencies of the devices are 0.7 and approximately 13.6%, respectively. In addition, PC-AFM, a recent notable method for nano-scale characterization of photovoltaic elements, is used for direct measurements of photoelectric characteristics in limited areas instead of large areas. The effects of changes in the intensity and wavelength of light shining on the element on the photoelectric characteristics are observed. Results obtained through PC-AFM are compared with the electric/optical characteristics data obtained through a solar simulator. The voltage(VPC-AFM) at which the current is 0 A in the I-V characteristic curves increases sharply up to 18 W/m2, peaking and slowly falling as light intensity increases. Here, VPC-AFM at 18 W/m2 is 0.29 V, which corresponds to 59 % of the average Voc value, as measured with the solar simulator. Furthermore, while the light wavelength increases from 300 nm to 1,100 nm, the external quantum efficiency(EQE) and results from PC-AFM show similar trends at the macro scale but reveal different results in several sections, indicating the need for detailed analysis and improvement in the future.
        4,000원
        84.
        2018.11 구독 인증기관·개인회원 무료
        An ionic polyacetylene with the pendent N-glycidylpyridinium bromide, poly(2-ethynyl-N-glycidylpyridinium bromide), was synthesized in 91% yield by the activated polymerization of 2-ethynylpyridine with epibromohydrin without any additional catalyst or catalyst. This polymer exhibited characteristic UV-visible absorption band at 515nm and yellow PL spectrum at 598nm corresponding to the photon energy of 2.07 eV. The cyclovoltamograms of polymer exhibited the electrochemically stable window in the region of 1.41.8V and the redox current value gradually increased as the scan rate increased. The kinetics of the redox process of polymer was found to be well-controlled by the reactant diffusion process from the experiment of the oxidation current density of PEGPB versus the scan rate.
        85.
        2018.11 구독 인증기관·개인회원 무료
        We have synthesized new alkylated indenopyrazine homopolymer and its copolymer having an alkylated spirofluorene moiety. Poly(6,6,12,12-(Tetra-2-ethylhexyl)-6,12-Dihydrodiindeno[1,2-b:1,2-e]pyrazine-2,8-diyl) [PEHIP] and Poly(6,6,12,12-(tetra-2-ethylhexyl)-6,12-dihydrodiindeno[1,2-b:1,2-e]pyrazine-co-20,30,60,70-tertrakis-octyloxy-9-spirofluorene) [PEHIPSF] were polymerized by using Yamamoto reaction. PEHIP and PEHIPSF showed the PL maximum values of 470 nm and 454 nm in PL spectra. The PEHIPSF was fabricated into an EL device and it exhibited the EL maximum value of 463 nm.
        86.
        2018.11 구독 인증기관·개인회원 무료
        The instrumental analysis data on the polymer structure revealed that the poly(PA) have the conjugated polyene backbone structure with phenyl substituents. The band gap energy of poly(PA) was estimated to be 2.51 eV and the photoluminescence spectra of poly(PA) showed that the photoluminescence peak is located at 439 nm, corresponding to a photon energy of 2.82 eV. The cyclovoltamograms of poly(PA) exhibited that the irreversible oxidation and reduction were occurred at 0.38V and 0.93 V, respectively (vs Ag=AgNO3). The redox current value gradually increased as the scan rate increased.
        87.
        2018.11 구독 인증기관·개인회원 무료
        The present polymer have a conjugated polymer backbone system with the designed substituents. The photoluminescence peak of polymer was observed at 525nm, which is corresponded to the photon energy of 2.36 eV and the band gap of poly(EBA) was 2.38 eV. The cyclovoltamograms of the polymer exhibited the irreversible electrochemical behaviors. It was found that the kinetics of the redox process of this conjugated polymer might be mainly controlled by the diffusion process from the experiment of the oxidation current density of polymer versus the scan rate.
        88.
        2018.11 구독 인증기관·개인회원 무료
        The electrochemical properties of poly(a-methylbenzyl dipropargylamine) was studied by cyclic voltametry. Poly(a-methylbenzyl dipropargylamine) was prepared by the cyclopolymerization of a-methylbenzyl dipropargylamine in high yield. The photoluminescence peaks of the present polymer was observed at 443nm corresponding to the photon energy of 2.80 eV. The cyclovoltamograms of the polymer exhibited the irreversible electrochemical behaviors between the doping and undoping peaks. It was found that the kinetics of the redox process of poly(MBDA) might be mainly controlled by the electron transfer process from the experiment of the oxidation current density of poly(MBDA) versus the scan rate.
        89.
        2018.11 구독 인증기관·개인회원 무료
        The activated polymerization of 2-ethynylpyridine by using 2-thiophenecarbonyl chloride yielded the corresponding conjugated ionic polymer, poly[2-ethynylN-(2-thiophenecarbonyl)pyridinium chloride] (PETCPC). The polymerization proceeded well to give high yield of polymer without any additional initiator or catalyst. The instrumental analysis data on polymer structure indicated that the present ionic polymer have a conjugated polymer backbone system having N-(2-thiophenecarbonyl)pyridinium chloride as substituents. The photoluminescence maximum peak of PETCPC was located at 573 nm, which corresponds to the photon energy of 2.16 eV. The aromatic functional substituents in the conjugated backbone system shift PL maximum values because it makes different molecule arrangement. The cyclovoltamograms of PETCPC exhibited the electrochemically stable window at 1.24 to 1.80 V region.
        90.
        2018.11 구독 인증기관·개인회원 무료
        최근 수자원 부족의 문제에 대한 탈출구를 찾기 위해 해수담수화 공정이 지속적인 연구가 이루어지고 있다. 그 중 전기흡착탈이온(EAD) 공정은 이온교환막을 이용한 전기투석법과 이온교환수지를 이용한 이온교환수지법을 혼합하여 이루어지는 공정으로 현재 사용되고 있는 해수담수화 공정의 효율을 더 높이 올려줄 것이라 예상하고 있다. 하지만, 이 공정은 이온교환막 사이에 이온교환수지가 있는 구조이기 때문에 기존 모듈보다 비교적 사이즈가 크다는 단점이 있다. 또한, 이온교환수지의 크기 분포와 당량비가 모듈의 성능에 영향을 준다. 본 연구는 현재 상용화되고 있는 이온교환공정에서 쓰이고 있는 모듈의 문제해결과 성능 향상을 위해 진행되었다. 개질을 통해 이온교환용량을 더욱 향상시키고 일반적인 이온교환수지가 아닌 더 작고 균질한 이온교환능력을 가진 이온교환 나노입자를 제조하여 제막을 진행하였고, 다양한 특성평가가 이루어졌다.
        91.
        2018.11 구독 인증기관·개인회원 무료
        Perfluorinated sulfonic acid (PFSA) ionomers have been used as polymer electrolyte membrane (PEM) materials owing to their excellent chemical durability and proton conductivity. However, the PFSA ionomers are suffering from fast hydrogen crossover and, thereby, chemical degradation in the membrane state. To solve these issues is to make reinforced membranes by filling proton-conductive PFSA ionomers in the pores of chemically robust poly(tetrafluoroethylene) (PTFE) support films. However, it is very difficult to obtain PFSA-PTFE reinforced membranes with improved hydrogen barrier property. In this study, PFSA-PTFE reinforced membranes were fabricated by immersing commercial reinforced membrane in PFSA ionomer dispersions with different chemical architectures and particle sizes and their effects were systematically investigated.
        92.
        2018.11 구독 인증기관·개인회원 무료
        Polymer electrolyte membrane fuel cells (PEMFCs) have been studied intensively due to their great potential as a clean and efficient energy conversion device. Especially, considerable attention has been paid to the development of thin polymer electrolyte membranes (PEMs) for the practical application of PEMFCs. However, thin PEMs normally have poor physicochemical stability. It is well-known that the physicochemical stability of polymer membrane can be improved by cross-linking technology. In this presentation two different types of cross-linked membranes from sulfonated poly(arylene ether sulfone) (SPAES) will be introduced: 1) cross-linked SPAES membranes prepared using flexible perfluoropolyether as a cross-linker. 2) End group cross-linked SPAES membranes prepared via simple thiol-ene click reaction.
        93.
        2018.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        축전식 탈염(capacitive deionization)에 이용할 수 있는 폴리페닐렌 옥사이드(PPO) 음이온 교환막의 가교결합에 대해 조사하였다. 브롬화와 아민화 반응단계를 거쳐 PPO 음이온 교환 고분자를 제조하고 비스페놀 A 디글리시딜에테르 (BADGE), m-페닐렌디아민(m-PDA), 헥사메틸렌디아민(HMDA) 등으로 가교하였다. 가교에 따른 겔화되는 시간은 HMDA > m-PDA > BADGE 순으로 짧았으며, 일정한 함량 이상으로 실온에서 가교하면 1-메틸피롤리돈(NMP)과 같은 비양성자성 용매(aprotic solvent)에 녹지 않아 내화학성이 증대되었다. 가교제(BADGE) 함량에 따른 음이온 교환막의 이온 교환 용량과 함 수율을 측정하고 비교하였다. HMDA 용액에 침적하여 표면 가교한 PPO 음이온 교환막을 축전식 탈염에 적용한 결과 그 탈염 성능은 가교하지 않은 막과 비교하여 흡착단계의 초기 부분을 제외하고 거의 차이가 없었다.
        4,000원
        94.
        2018.08 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        An effective cleaning method for Ni removal in Ni-induced lateral crystallization(Ni-MILC) poly-Si TFTs and their electrical properties are investigated. The HCN cleaning method is effective for removal of Ni on the crystallized Si surface, while the nitric acid treatment results decrease by almost two orders of magnitude in the Ni concentration due to effective removal of diffused Ni mainly in the poly-Si grain boundary regions. Using the HCN cleaning method after the nitric acid treatment, re-adsorbed Ni on the Si surfaces is effectively removed by the formation of Ni-cyanide complexions. After the cleaning process, important electrical properties are improved, e.g., the leakage current density from 9.43 × 10−12 to 3.43 × 10−12 A and the subthreshold swing values from 1.37 to 0.67 mV/dec.
        4,000원
        95.
        2018.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        올레핀/파라핀 분리를 위해 poly(ethylene oxide)(PEO)/Ag nanoparticles (AgNPs)(전구체: AgBF4)/p-benzoquinone (p-BQ) 복합막이 제조되었으며, 이 복합체 분리막의 성능은 100시간까지 선택도 10과 투과도 15 GPU로 유지되는 것이 관찰 되었다. 분리막의 성능이 100시간까지 유지할 수 있었던 이유는 p-BQ의 첨가로 인해 Ag ion이 안정적으로 Ag nanoparticles 로 형성될 수 있었을 뿐더러 전자수용체인 p-BQ으로 인해 표면이 부분 양극성화 되어 올레핀 운반체로서 역할을 성공적으로 수행한 결과라 생각되었다. 본 연구에서는 Ag nanoparticles의 전구체로 사용된 AgBF4의 가격이 고가이기 때문에 가격 측면에서 유리한 AgNO3 Ag nanoparticles의 전구체로 사용하여 실험을 진행하였다. 그 결과로서 AgNO3의 경우에는 앞선 AgBF4 과는 다르게 안정적으로 은 나노입자가 형성되지 못하고 이로 인하여 좋은 성능을 내지 못하는 것으로 분석되었다.
        4,000원
        96.
        2018.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 가교막을 poly(2,6-dimethyl-1,4-phenylene oxide)(PPO)에 브롬화반응을 통해 제조한 Br-PPO를 주 사슬로 성공적으로 제조하였고, 키토산과 4차암모늄이 포함된 키토산을 가교제로 사용하였다. 제조된 가교막은 트리메틸아민 용액에 함침하여 후처리를 진행하였다. 그리고 가교도는 가교제 비율을 이용하여 조절하였다. 이렇게 제조된 A-PPO + chitosan 가교막과 A-PPO + QA-chitosan 가교막의 이온교환막으로써의 가능성을 여러 특성평가로 확인하였다. Chitosan을 사용한 가교막보다 QA-chitosan을 사용한 가교막이 가교가 더 잘 이루어졌으며, QA-chitosan의 함량이 증가할수록 이온교환용량이 1.18 meq/g에서 1.53 meq/g까지 증가하는 경향, 함수율이 21.6%에서 42.2%까지 증가하는 경향을 나타내었다.
        4,000원
        97.
        2018.05 구독 인증기관·개인회원 무료
        Modified asphalt pavements are needed to resolve pavement distress problems like rutting, pot-hole and warm asphalt pavements are needed to solve energy saving, reduction of noxious gasses emission and early traffic opening. To present these two characteristics, we developed polymer-modified warm-mix asphalt binder and mixtures and evaluated their performance by optimizing polymer-modified warm-mix additive. As results, physical properties and rheological characteristics of polymer-modified warm-mix asphalt binder are similar to normal modified binder. And we confirmed that polymer-modified warm-mix asphalt mixtures satisfied quality standard of Ministry of Land, Infrastructure and Transport.
        98.
        2018.05 구독 인증기관·개인회원 무료
        Fly ash is used as alumina-silicate resource material to reaction processing on geopolymer materials. The strength of material is belonging to alkaline liquid, fly ash, activity reaction of fly ash. Geopolymer concrete as non-toxic, bleed free and high strength material can be used for construction on rigid pavement. Study on influence of polypropylene fiber on performance characteristic of geopolymer concrete is considered. In this research, the mix proportion with fly ash and alkaline liquid is used to react on geopolymer concrete. The poly-propylene fiber in range from 0 to 0.5% by volume is added in mixture of geopolymer concrete. The ratio between length and diameter in range of 100-500 is investigated. The results are indicated that workability of fresh concrete is reduced by using poly-propylene fiber. The adding of poly-propylene fiber is significantly affected on characteristic of geopolymer concrete. Poly-propylene fiber can be distributed in fly ash matrix and reduced shrinkage of concrete during activation. After geopolymerization, compressive and the flexural strength of concrete produced with fibers are enhanced up to 10% and 20%, respectively. However, when the length to diameter ratio increases, compressive strength is tended to decrease with mixture using polypropylene fiber.
        99.
        2018.05 구독 인증기관·개인회원 무료
        The anion exchange membrane fuel cells (AEMFCs) have been known to be promising eco-friendly power sources. To develop AEMFCs, the high ion conductivity, good dimensional, mechanical and alkaline stabilities are required for AEMs. However, the high conductivity generally requires high water uptake, which causes an enhanced swelling and decreased mechanical properties for the AEMs. To overcome this problem, we introduced an ionic conductor having long alkyl diammonium groups to alkyl-substituted poly(p-phenylene oxide) (PPO). Addition of this new additive increased the conductivity, mechanical and alkaline stabilities due to the molecular interaction between alkyl chains in PPO and same group of the additive. Synthesis and properties of the corresponding membranes will be discussed in detail.
        100.
        2018.05 구독 인증기관·개인회원 무료
        Polymer electrolyte membrane fuel cells (PEMFCs) have attracted particular interest as alternative and enviromentally friendly energy source for both mobile and stationary application. The perfluorosulfonic acid membranes, such as Nafion® are most used PEMs because of their good chemical and electrochemical stability. However they have drawbacks such as high cost, low application temperature, insufficient durability. Sulfonated poly (arylene ether)s, poly (phenylene ether)s, poly (arylene ether ketone)s have beem developed. This work is an attempt to synthesize sulfonated poly (arylene ether)s contained phosphinate moiety which is pendant phenyl structure. Sulfonated poly (arylene ether)s membranes were prepared from DOPO-BPA, 4,4’-sulfonyl diphenol(SFDPS), 1,4-bis(4-fluoro benzoyl)benzene(1,4-FBB).
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