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        검색결과 5

        1.
        2021.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        As the size of market for electric vehicles and energy storage systems grows, the demand for lithium-ion batteries (LIBs) is increasing. Currently, commercial LIBs are fabricated with liquid electrolytes, which have some safety issues such as low chemical stability, which can cause ignition of fire. As a substitute for liquid electrolytes, solid electrolytes are now being extensively studied. However, solid electrolytes have disadvantages of low ionic conductivity and high resistance at interface between electrode and electrolyte. In this study, Li7La3Zr2O12 (LLZO), one of the best ion conducting materials among oxide based solid electrolytes, is fabricated through RF-sputtering and various electrochemical properties are analyzed. Moreover, the electrochemical properties of LLZO are found to significantly improve with co-sputtered Li2O. An all-solid thin film battery is fabricated by introducing a thin film solid electrolyte and an Li4Ti5O12 (LTO) cathode; resulting electrochemical properties are also analyzed. The LLZO/Li2O (60W) sample shows a very good performance in ionic conductivity of 7.3  108 S/cm, with improvement in c-rate and stable cycle performance.
        4,000원
        2.
        2018.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We examined the characteristics of indium tin zinc oxide (ITZO) thin film transistors (TFTs) on polyimide (PI) substrates for next-generation flexible display application. In this study, the ITZO TFT was fabricated and analyzed with a SiOx/ SiNx gate insulator deposited using plasma enhanced chemical vapor deposition (PECVD) below 350℃. X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectroscopy (SIMS) results revealed that the oxygen vacancies and impurities such as H, OH and H2O increased at ITZO/gate insulator interface. Our study suggests that the hydrogen related impurities existing in the PI and gate insulator were diffused into the channel during the fabrication process. We demonstrate that these impurities and oxygen vacancies in the ITZO channel/gate insulator may cause degradation of the electrical characteristics and bias stability. Therefore, in order to realize high performance oxide TFTs for flexible displays, it is necessary to develop a buffer layer (e.g., Al2O3) that can sufficiently prevent the diffusion of impurities into the channel.
        4,000원
        3.
        2017.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Aluminum-oxide(Al2O3) thin films were deposited by electron cyclotron resonance plasma-enhanced atomic layer deposition at room temperature using trimethylaluminum(TMA) as the Al source and O2 plasma as the oxidant. In order to compare our results with those obtained using the conventional thermal ALD method, Al2O3 films were also deposited with TMA and H2O as reactants at 280 oC. The chemical composition and microstructure of the as-deposited Al2O3 films were characterized by X-ray diffraction(XRD), X-ray photo-electric spectroscopy(XPS), atomic force microscopy(AFM) and transmission electron microscopy(TEM). Optical properties of the Al2O3 films were characterized using UV-vis and ellipsometry measurements. Electrical properties were characterized by capacitance-frequency and current-voltage measurements. Using the ECR method, a growth rate of 0.18 nm/cycle was achieved, which is much higher than the growth rate of 0.14 nm/cycle obtained using thermal ALD. Excellent dielectric and insulating properties were demonstrated for both Al2O3 films.
        4,000원
        4.
        2016.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Nine species of fossil plants were described based on the new material collected from the Hasandong Formation. They are as follows: Thallites yabei, Onychiopsis elongata, Cladophlebis denticulata, C. shinshuensis, C. (Eboracia ?) lobifolia, C. (Klukia ?) koraiensis, Brachyphyllum japonicum, Elatocladus tennerima, and Taeniopteris ? sp. cf. T. auriculata. The floristic composition of the Hasandong flora is very similar to that of the Nakdong flora. This means that both floras might have flourished under subtropical warm arid climate. This flora contains both the Tetori-type and Ryoseki-type floras. It is considered that the Hasandong flora is a member of the Mixed-type floras that existed in eastern Eurasia during the Late Jurassic to Early Cretaceous time.
        4,600원
        5.
        2015.02 KCI 등재 구독 인증기관·개인회원 무료
        The book of ‘World Museum of National History’ includes an analysis of the origin of natural history and howthe natural museums function and play a role. The book also describes details of the current situation of the naturalhistory museums around the world. It is expected that the book helps advance and spread ‘the scientific culture’ as wellas it assists to increase the awareness of the importance of science among the general public. the natural museums function and play a role. The book also describes details of the current situation of the natural history museums around the world. It is expected that the book helps advance and spread ‘the scientific culture’ as well as it assists to increase the awareness of the importance of science among the general public.