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        검색결과 855

        362.
        2013.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In the segmented-in-series solid-oxide fuel cells (SIS-SOFCs), fabrication techniques which use decalcomania paper have many advantages, i.e., an increased active area of the electrode; better interfacial adhesion property between the anode, electrolyte and cathode; and improved layer thickness uniformity. In this work, a cell-stack was fabricated on porous ceramic flattened tube supports using decalcomania paper, which consists of an anode, electrolyte, and a cathode. The anode layer was 40μm thick, and was porous. The electrolyte layers exhibited a uniform thickness of about 20μm with a dense structure. Interfacial adhesion was improved due to the dense structure. The cathode layers was 30μm thick with porous structure, good adhesion to the electrolyte. The ohmic resistance levels at 800, 750 and 700˚C were measured, showing values of 1.49, 1.58 and 1.65Ω·cm2, respectively. The polarization resistances at 800, 750 and 700˚C were measured to be 1.63, 2.61 and 4.17cm2, respectively. These lower resistance values originated from the excellent interfacial adhesion between the anode, electrolyte and cathode. In a two-cell-stack SOFC, open-circuit voltages(OCVs) of 1.915, 1.942 and 1.957 V and maximum power densities(MPD) of 289.9, 276.1 and 220.4mW/cm2 were measured at 800, 750 and 700˚C, respectively. The proposed fabrication technique using decalcomania paper was shown to be feasible for the easy fabrication of segmented-in-series flattened tube SOFCs.
        4,000원
        363.
        2013.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this paper, we studied a p-type reflector based on indium tin oxide (ITO) for vertical-type ultraviolet light-emitting diodes (UV LEDs). We investigated the reflectance properties with different deposition methods. An ITO layer with a thickness of 50 nm was deposited by two different methods, sputtering and e-beam evaporation. From the measurement of the optical reflection, we obtained 70% reflectance at a wavelength of 382 nm by means of sputtering, while only 30% reflectance resulted when using the e-beam evaporation method. Also, the light output power of a 1mm×1mm vertical chip created with the sputtering method recorded a twofold increase over a chip created with e-beam evaporation method. From the measurement of the root mean square (RMS), we obtained a RMS value 1.3 nm for the ITO layer using the sputtering method, while this value was 5.6 nm for the ITO layer when using the e-beam evaporation method. These decreases in the reflectance and light output power when using the e-beam evaporation method are thought to stem from the rough surface morphology of the ITO layer, which leads to diffused reflection and the absorption of light. However, the turn-on voltage and operation voltage of the two samples showed identical results of 2.42 V and 3.5 V, respectively. Given these results, we conclude that the two ITO layers created by different deposition methods showed no differences in the electric properties of the ohmic contact and series resistance.
        4,000원
        365.
        2013.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        ZnO thin films co-doped with Mg and Ga (MxGyZzO, x+y+z=1, x=0.05, y=0.02 and z=0.93) were preparedon glass substrates by RF magnetron sputtering with different sputtering powers ranging from 100W to 200W at a substratetemperature of 350oC. The effects of the sputtering power on the structural, morphological, electrical, and optical propertiesof MGZO thin films were investigated. The X-ray diffraction patterns showed that all the MGZO thin films were grown asa hexagonal wurtzite phase with the preferred orientation on the c-axis without secondary phases such as MgO, Ga2O3, orZnGa2O4. The intensity of the diffraction peak from the (0002) plane of the MGZO thin films was enhanced as the sputteringpower increased. The (0002) peak positions of the MGZO thin films was shifted toward, a high diffraction angle as thesputtering power increased. Cross-sectional field emission scanning electron microscopy images of the MGZO thin filmsshowed that all of these films had a columnar structure and their thickness increased with an increase in the sputtering power.MGZO thin film deposited at the sputtering power of 200W showed the best electrical characteristics in terms of the carrierconcentration (4.71×1020cm−3), charge carrier mobility (10.2cm2V−1s−1) and a minimum resistivity (1.3×10−3Ωcm). A UV-visible spectroscopy assessment showed that the MGZO thin films had high transmittance of more than 80% in the visibleregion and that the absorption edges of MGZO thin films were very sharp and shifted toward the higher wavelength side, from270nm to 340nm, with an increase in the sputtering power. The band-gap energy of MGZO thin films was widened from3.74eV to 3.92eV with the change in the sputtering power.
        4,000원
        370.
        2013.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The Cu2ZnSnS4 (CZTS) thin film solar cell is a candidate next generation thin film solar cell. For the application of an absorption layer in solar cells, CZTS thin films were deposited by pulsed laser deposition (PLD) at substrate temperature of 300˚C without post annealing process. Deposition time was carefully adjusted as the main experimental variable. Regardless of deposition time, single phase CZTS thin films are obtained with no existence of secondary phases. Irregularly-shaped grains are densely formed on the surface of CZTS thin films. With increasing deposition time, the grain size increases and the thickness of the CZTS thin films increases from 0.16 to 1μm. The variation of the surface morphology and thickness of the CZTS thin films depends on the deposition time. The stoichiometry of all CZTS thin films shows a Cu-rich and S-poor state. Sn content gradually increases as deposition time increases. Secondary ion mass spectrometry was carried out to evaluate the elemental depth distribution in CZTS thin films. The optimal deposition time to grow CZTS thin films is 150 min. In this study, we show the effect of deposition time on the structural properties of CZTS thin film deposited on soda lime glass (SLG) substrate using PLD. We present a comprehensive evaluation of CZTS thin films.
        4,000원
        371.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구의 주된 목적은 대한민국 주변도의 제작에 가장 적절한 투영법이 무엇인지를 결정하는 것이다. 이 목적을 달성하기 위해 다음과 같은 구체적인 연구과제를 설정한다. 첫째, 기제작된 지도와 투영법 선정의 가이드라인을 참조하여 몇 개의 후보 투영법을 선정한다. 둘째, 왜곡도 분석 기법에 대한 상세한 리뷰를 통해 투영 왜곡 분석을 위한 기본 방향을 설정한다. 셋째, GIS-기반 투영 왜곡 분석을 실시하고 그 결과를 바탕으로 최종의 투영법을 선정한다. 주요 연구 결과를 요약하면 다음과 같다. 첫째, 람베르트 정형원추도법, 알베르스 정적원추도법, 람베르트 정적방위도법, 그리고 정거방위도법이 일차적인 후보 투영법으로 선정되었다. 둘째, 극소 스케일의 국지적 왜곡도 지수를 사용하는 것이 가장 적절하며, 국지적 왜곡도의 값이 실질적으로 산출되어 공간적 분포의 시각화나 통계량 계산을 위해 사용되어야 한다는 점이 인식되었다. 셋째, 투영 왜곡 분석을 위한 플랫폼으로 PDAT(Projection Distortion Analysis Tool)가 선정되었는데, 이것은 국지적 왜곡도 지수에 기반하고 있으며, GIS 상에서 투영 왜곡 분석을 할 수 있는 환경을 제공한다. PDAT를 통해 투영 왜곡 분석이 실시되었고, 그 결과에 대한 종합적인 검토 결과 람베르트 정적방위도법이 최종적인 투영법으로 선정되었다. 본 연구는 대한민국 전도에 대한 적절한 투영법이 무엇인지에 대한 논의에 많은 시사점을 제공할 것으로 보인다.
        4,900원
        372.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문에서는 모션그래픽을 이용한 다양한 콘텐츠 제작 기법에 대해서 나타내었다. 모션그래픽은 영상 커뮤니케이션 언어로서 움직이는 그래픽이라고 할 수 있다 모션그래픽의 특징은 콘텐츠에 상용 작용한다 움직임은 시간과 공간의 개념을 가지고 있다 움직임은 애니메이션으로 표현되어 게임으로 응용된다 모션 그래픽은 이미지 비디오 사운드 등의 요소들을 이용하여 창의적이고 효과적인 영상들을 만든다 모션그래픽은 웹 문서를 포함하여 비디오 제작 게임 등 다양한 콘텐츠들을 제작 할 수 있다 본 논문에서는 모션 콘텐츠 제작을 위하여 다양한 콘텐츠 표현 기법들을 나타냈다.
        4,800원
        374.
        2012.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문은 두 편으로 구성된 치과용 임플란트 구조설계에 대한 논문 중 두 번째 논문으로 첫 번째 논문에서 구조해석 비 교연구를 통하여 그 구조적 성능이 확인된 새로운 임플란트 구조모델에 대하여 시험 설계도면을 작성하여 완성하였으며, 이를 근거로 실제로 CNC 공작기계 등을 이용하여 임플란트를 가공․제작하고, 이를 평가함으로써 치과용 임플란트 구조 설계를 완성하였다. 설계도면 작업은 전용 Tool인 MDT를 이용하여 수행하였으며, 가공작업은 CNC 선반, 범용밀링머신, Wire EDM 등을 이용하여 수행하였다. 전자현미경을 이용하여 임플란트 표면의 가공 상태를 최종 평가 확인하였다. 평가 결과 매우 양호한 상태의 임플란트 시험제품을 설계 제작하였다.
        4,000원
        375.
        2012.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        4,000원
        376.
        2012.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        When a new nuclear fuel is developed, irradiation test needs to be carried out in the research reactor to analyze the performance of the new nuclear fuel. It is necessary to attach sensors in the fuel rod and connect them with instrumentation cables to check the performance of the nuclear fuel during the burn up test in the test loop. A thermocouple is installed at the center of the fuel rod to check the centerline temperature of a fuel rod during the irradiation test. Therefore, A hole needs to be made at the center of a fuel pellet to put the thermocouple. However, it is difficult to make a small fine hole on the sintered UO2 pellet with a simple drilling machine, because the hardness and density of a sintered UO2 pellet are very high. In this study, an instrumented fuel rod mock-up was fabricated using an automated precise drilling machine. Four sintered alumina were drilled off and assembled into the zircaloy tube and a thermocouple was instrumented in the fuel rod mock-up. Sealing of an instrumented fuel rod mock-up was performed in the following two methods. It is sealing of similar metals perform by welding method, and sealing of dissimilar metals perform by swagelok method.
        4,000원
        377.
        2012.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This research focuses on the role of Giovanni Marinioni during the formation of the modern cartography and cadastre during the 18th century. Initial study began with Giambattista Nolli's Roman map noticing not much information was available to acknowledge his activities during his Milan period before the departure to Rome. It became evident that Marinoni was a key person to understand the complex circumstances in which the professional training and formation of Giambattista Nolli took place as later worked as an anonymous intern during the elaboration of Theresian Cadastre of Milan. The other important figures are Leandro Anguissola and Giovanni Filippini. Anguissola's position and precedent work facilitated Marinoni's multidisciplinary activities that he had performed in Vienna and Milano in the field of making urban maps of those two cities. On the other hand, Filippini not only collaborated with Marinoni but also introduced Nolli in the field of cartography. These activities show transitional and dual aspects that characterized the period in which important irreversible changes that occur during the reign of Habsburg empire and in the rest of the Europe toward the formation of modern society and state. Marinoni's theories and praxis greatly influenced Nolli's later commitment under the Savoia and later on the elaboration of the 'Pianta Grande di Roma' in 1748.
        4,000원