• Title/Summary/Keyword: IT Diffusion

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Novel synthesis of nanocrystalline thin films by design and control of deposition energy and plasma

  • Han, Jeon G.
    • Proceedings of the Korean Vacuum Society Conference
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    • 2016.02a
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    • pp.77-77
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    • 2016
  • Thin films synthesized by plasma processes have been widely applied in a variety of industrial sectors. The structure control of thin film is one of prime factor in most of these applications. It is well known that the structure of this film is closely associated with plasma parameters and species of plasma which are electrons, ions, radical and neutrals in plasma processes. However the precise control of structure by plasma process is still limited due to inherent complexity, reproducibility and control problems in practical implementation of plasma processing. Therefore the study on the fundamental physical properties that govern the plasmas becomes more crucial for molecular scale control of film structure and corresponding properties for new generation nano scale film materials development and application. The thin films are formed through nucleation and growth stages during thin film depostion. Such stages involve adsorption, surface diffusion, chemical binding and other atomic processes at surfaces. This requires identification, determination and quantification of the surface activity of the species in the plasma. Specifically, the ions and neutrals have kinetic energies ranging from ~ thermal up to tens of eV, which are generated by electron impact of the polyatomic precursor, gas phase reaction, and interactions with the substrate and reactor walls. The present work highlights these aspects for the controlled and low-temperature plasma enhanced chemical vapour disposition (PECVD) of Si-based films like crystalline Si (c-Si), Si-quantum dot, and sputtered crystalline C by the design and control of radicals, plasmas and the deposition energy. Additionally, there is growing demand on the low-temperature deposition process with low hydrogen content by PECVD. The deposition temperature can be reduced significantly by utilizing alternative plasma concepts to lower the reaction activation energy. Evolution in this area continues and has recently produced solutions by increasing the plasma excitation frequency from radio frequency to ultra high frequency (UHF) and in the range of microwave. In this sense, the necessity of dedicated experimental studies, diagnostics and computer modelling of process plasmas to quantify the effect of the unique chemistry and structure of the growing film by radical and plasma control is realized. Different low-temperature PECVD processes using RF, UHF, and RF/UHF hybrid plasmas along with magnetron sputtering plasmas are investigated using numerous diagnostics and film analysis tools. The broad outlook of this work also outlines some of the 'Grand Scientific Challenges' to which significant contributions from plasma nanoscience-related research can be foreseen.

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The Correlation between Japanese Animation and Spyri's (일본 애니메이션 <알프스 소녀 하이디>와 슈피리 문학과의 연관성)

  • Park, Gi-Ryung
    • Cartoon and Animation Studies
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    • s.37
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    • pp.247-265
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    • 2014
  • This essay is about the considering the mutual relevance of animation and literary work in a case. The television animation Heidi, Girl of the Alps made in Japan is the most famous media version of the original novel. The novel Heidi by the Switzerland writer Johanna Spyri has been translated in a lot of countries, and the original Heidi has been adapted for mass media - literary(translation), movie, play, animation, cartoon, picture book. Here, with the relation between animation Heidi, Girl of the Alps and Spyri's Heidi and the present condition of the change in Japan and Korea, the relevance of animation and literature was reconsidered. First, Heidi, Girl of the Alps and Heidi have the different characteristic as media, and the content has some different set-up. On the other hand, original soul is inherited in the animation. Second, the animation has affected Heidi related visual image and the original media diffusion. The above consideration from a viewpoint of the mutual relevance between media shows the importance to return aiming at mutual understanding of animation and literature and mutual value between the diversified media. Moreover, it suggests a possibility of leading to creation of the energy which results in transformation also to action.

Al2O3 High Dense Single Layer Gas Barrier by Neutral Beam Assisted Sputtering (NBAS) Process

  • Jang, Yun-Seong;Hong, Mun-Pyo
    • Proceedings of the Korean Vacuum Society Conference
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    • 2015.08a
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    • pp.157-157
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    • 2015
  • Recently, the growing interest in organic microelectronic devices including OLEDs has led to an increasing amount of research into their many potential applications in the area of flexible electronic devices based on plastic substrates. However, these organic devices require a gas barrier coating to prevent the permeation of water and oxygen because organic materials are highly susceptible to water and oxygen. In particular, high efficiency OLEDs require an extremely low water vapor transition rate (WVTR) of $1{\times}10^{-6}g/m^2day$. The Key factor in high quality inorganic gas barrier formation for achieving the very low WVTR required ($1{\times}10^{-6}g/m^2day$) is the suppression of defect sites and gas diffusion pathways between grain boundaries. In this study NBAS process was introduced to deposit enhanced film density single gas barrier layer with a low WVTR. Fig. 1. shows a schematic illustration of the NBAS apparatus. The NBAS process was used for the $Al_2O_3$ nano-crystal structure films deposition, as shown in Fig. 1. The NBAS system is based on the conventional RF magnetron sputtering and it has the electron cyclotron resonance (ECR) plasma source and metal reflector. $Ar^+$ ion in the ECR plasma can be accelerated into the plasma sheath between the plasma and metal reflector, which are then neutralized mainly by Auger neutralization. The neutral beam energy is controlled by the metal reflector bias. The controllable neutral beam energy can continuously change crystalline structures from an amorphous phase to nanocrystal phase of various grain sizes. The $Al_2O_3$ films can be high film density by controllable Auger neutral beam energy. we developed $Al_2O_3$ high dense barrier layer using NBAS process. We can verified that NBAS process effect can lead to formation of high density nano-crystal structure barrier layer. As a result, Fig. 2. shows that the NBAS processed $Al_2O_3$ high dense barrier layer shows excellent WVTR property as a under $2{\times}10^{-5}g/m^2day$ in the single barrier layer of 100nm thickness. Therefore, the NBAS processed $Al_2O_3$ high dense barrier layer is very suitable in the high efficiency OLED application.

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A Regional Study on the Korean Toilet Culture (韓國 통시(뒷간) 文化의 地域的 硏究)

  • ;Chang, Bo-Woong
    • Journal of the Korean Geographical Society
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    • v.30 no.3
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    • pp.255-268
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    • 1995
  • According to cultural diffusion route, the Korean toilet culture could be classified as southern culture and northern culture, In Cheju Island the toilet is located on the stone fence of swine. The native people of Cheju Island name it as TONGSHI. And Southern culture could be diffused from South Sea to Cheju Island by the sea current. Around Mt.Chiri area, the greater part of traditional toilets are on the upper floor in the barn, and pigs are on the bottom floor under the toilet. This type of toilet would be the northern culture of the toilet, which would be diffused from continent of Asia to Korean Peninsula. Residents of these areas also name this toilet as TONGSHI. The Korean word "TONGSHI" means a toilet on the pig fence. Traditional toilet culture in Korea differs from regions and residents. We can find dry-closets in Seon-am Temple and Song-kawng Temple. This high floor dry-closet type would be effected by Buddhism. In the reclaimed land and islands of west sea we could not find the old traditional toilets.l toilets.

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Study on Environmental Factors of Inquiry Instruction of Secondary School Science Teachers (중.고등학교 과학교사의 탐구수업 환경 요인에 관한 연구)

  • Lee, Hyun-Uk;Shim, Kew-Cheol;Yeau, Sung-Hee;Chang, Nam-Kee
    • Journal of The Korean Association For Science Education
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    • v.18 no.3
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    • pp.443-450
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    • 1998
  • This study was performed to find the environmental factors of inquiry instruction perceived by secondary school science teacher. The instrument consisted of three domains such as teaching conditions, viewpoints of secondary school science teachers of environmental factors for inquiry instruction, and barrier and improve! rent factors of inquiry instruction. Teaching conditions between middle school and high school science teachers were not different significantly. Environmental factors of inquiry instruction of secondary school science teacher included five factors such as 'facilities and encouragement', 'amount of works and materials', 'teacher education and textbook', 'practice and knowledge' and 'perception of necessity and satisfaction'. And all factors except 'perception of necessity and satisfaction' were very low state for inquiry instruction. In the disturbant and improving factors, the critical factors were 'over students per class', 'textbook' and 'learning materials' for middle school science teachers, and 'over students per class', and 'entrance examination' for high school science teachers. Thus the development and diffusion of adequate inquiry learning materials may be helpful to practicing inquiry instruction as decrease of works and psychological charges, and it is needed to reorganize systematically and intensify pre- and in-service teacher education to practice inquiry instruction.

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Factors Affecting the Accuracy of Internet Survey (인터넷 여론조사의 정확도 관련요인)

  • Cho, Sung-Kyum;Joo, Young-Soo;Cho, Eun-Hee
    • Survey Research
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    • v.6 no.2
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    • pp.51-74
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    • 2005
  • The internet survey methods have been more and more widely used as the coverage of the fixed-line telephone is being reduced due to the diffusion of mobile phone. So, there is a need to know the accuracy of this new survey method. This study aims to estimate the accuracy of the internet survey method and identify the factors affecting the accuracy of this method, For this purpose, we analyzed the election poll data during the 17th general election period. These data include fixed-line telephone survey data, internet survey data, mobile phone survey data and the election voting data. The analysis shows that the prediction errors of the internet survey were a little more than those of the telephone or mobile phone survey. But the differences are not significant. It follows from this result that we can use the internet survey method in social survey context. This study also found that the respondent's willingness to participate in the survey, the probability of being at home during survey and the respondent's educational level were affecting the accuracy of the internet survey. Further studies to develop weighting method with these factors are needed.

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Synthesis and Electrochemical Properties of Li[Fe0.9Mn0.1]PO4 Nanofibers as Cathode Material for Lithium Ion Battery by Electrospinning Method (전기방사를 이용한 리튬 이차전지용 양극활물질 Li[Fe0.9Mn0.1]PO4 나노 섬유의 합성 및 전기화학적 특성)

  • Kim, Cheong;Kang, Chung-Soo;Son, Jong-Tae
    • Journal of the Korean Electrochemical Society
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    • v.15 no.2
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    • pp.95-100
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    • 2012
  • $LiFePO_4$ is an attractive cathode material due to its low cost, good cyclability and safety. But it has low ionic conductivity and working voltage impose a limitation on its application for commercial products. In order to solve these problems, the iron($Fe^{2+}$)site in $LiFePO_4$ can be substituted with other transition metal ions such as $Mn^{2+}$ in pursuance of increase the working voltage. Also, reducing the size of electrode materials to nanometer scale can improve the power density because of a larger electrode-electrolyte contact area and shorter diffusion lengths for Li ions in crystals. Therefore, we chose electrospinning as a general method to prepare $Li[Fe_{0.9}Mn_{0.1}]PO_4$ to increase the surface area. Also, there have been very a few reports on the synthesis of cathode materials by electrospinning method for Lithium ion batteries. The morphology and nanostructure of the obtained $Li[Fe_{0.9}Mn_{0.1}]PO_4$ nanofibers were characterized using scanning electron microscopy(SEM). X-ray diffraction(XRD) measurements were also carried out in order to determine the structure of $Li[Fe_{0.9}Mn_{0.1}]PO_4$ nanofibers. Electrochemical properties of $Li[Fe_{0.9}Mn_{0.1}]PO_4$ were investigated with charge/discharge measurements, electrochemical impedance spectroscopy measurements(EIS).

Characterization of transparent Sb-doped $SnO_2$ conducting films by XPS analysis (XPS를 이용한 Sb-doped $SnO_2$ 투명전도막의 특성 분석)

  • 임태영;김창열;심광보;오근호
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.13 no.5
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    • pp.254-259
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    • 2003
  • In the fabrication process of transparent conducting thin films of the ATO (antimony-doped tin oxide) on a soda lime glass substrate by a sol-gel dip coating method, the effects of the $SiO_2$ buffer layer formed on the substrate and $N_2$ annealing treatment were investigated by XPS (X-ray photoelectron spectroscopy) analysis. Optical transmittance and electrical resistivity of the 400 nm-thick ATO thin films which were deposited on $SiO_2$ buffer layer/soda lime glass and then annealed under nitrogen atmosphere were 84 % and $5.0\times 10^{-3}\Omega \textrm{cm}$ respectively. The XPS analysis confirmed that a $SiO_2$ buffer layer inhibited Na ion diffusion from the substrate, resulting in prohibiting the formation of a secondary phase such as $Na_2SnO_3$ and SnO and increasing Sb ion concentration and ratio of $Sb^{5+}/Sb^{3+}$ in the film. And it was also found that $N_2$ annealing treatment leads to the reduction of $Sn^{4+}$as well as $Sb^{5+}$ however the reduction of $Sn^{4+}$ is more effective and therefore consequently results in decrease in the electrical resistivity to produce an excellent electrical properties of the film.

Characteristics of reoxidation of nitried oxide for gate dielectric of charge trapping NVSM (전하트랩형 NVSM의 게이트 유전막을 위한 질화산화막의 재산화특성에 관한 연구)

  • 이상은;한태현;서광열
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.11 no.5
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    • pp.224-230
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    • 2001
  • The characteristics of $NO/N_2O$ annealed reoxidized nitrided oxide being studied as super thin gate oxide and gate dielectric layers of Non-Volatile Semiconductor Memory (NVSM) were investigated by Dynamic Secondary Ion Mass Spectrometry (D-SIMS), Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), and Auger Electron Spectroscopy (AES). The specimen was annealed by $NO/N_2O$ after initial oxide process and then rcoxidized for nitrogen redistribution in nitrided oxide. Out-diffusion of incorporated nitrogen during the wet oxidation in reoxidation process took place more strongly than that of the dry oxidation. It seems to indicate that hydrogen plays a role in breaking the Si N bonds. As reoxidation proceeds, incorporated nitrogen of $NO/N_2O$ annealed nitrided oxide is obsen-ed to diffuse toward the surface and substrate at the same time. ToF-SIMS results show that SiON species are detected at the initialoxide interface, and Si,NO species near the new $Si_2NO$ interface that formed after reoxidation. These SiON and $Si_2NO$ species most likely to relate to the origin of the state of memory charge traps in reoxidized nitrided oxide, because nitrogen dangling bonds of SiON and silicon dangling bonds of $Si_2NO$ are contained defects associated with memory effect.

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A Study on the Domestic Scale-up Policy Direction through the Analysis of Scale-up Support Policy for Global Startups (글로벌 창업기업 스케일업(Scale-up) 지원 정책 분석을 통한 국내 스케일업 정책 방향에 관한 연구)

  • Hong, Dae Ung;Jun, Byung Hoon
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.14 no.6
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    • pp.11-27
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    • 2019
  • The second venture "boom" diffusion strategy can be confirmed to be focused only on financing investment and finance, including achieving 5 trillion won annually in new venture investments, creating 20 unicorns, activating M&As and creating dynamic recovery markets. Of course, existing studies show that the fund is a very important policy for corporate growth, but various policy support will be needed to effectively scale up. To overcome these limitations, the scale-up support policies already in operation are analyzed by introducing scale-up policies in advanced countries such as the U.S. and Britain. It also aims to analyze domestic scale-up policies to draw up implications for establishing more effective scale-up policies. Academically, we are very lacking in research on scale-up at home and abroad, and we propose suggestions through this comparative study of policy cases to contribute to the promotion of various studies related to the scalability aspects of future research topics related to scale-up.