• 전자공학회논문지
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• 제50권7호
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• pp.115-121
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• 2013

본 연구에서는 TiInZnO(TiIZO)를 채널층으로 하는 thin film transistors(TFTs)를 제작하였다. TiIZO 층은 InZnO(IZO)와 Ti target을 이용하여 RF-magnetron co-sputtering system 방식으로 상온에서 증착하였으며, 어떠한 열처리도 하지 않았다. Ti의 첨가가 어떠한 영항을 주는지 연구하기 위해 X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS) 분석을 시행하였으며, 전기적인 특성을 측정하였다. Ti의 첨가는 Ti target의 rf power 변화에 따라 달리하였다. Ti의 첨가가 전류점멸비에 큰 영향을 주는 것을 확인하였고, 이것은 Ti의 산화력이 In과 Zn보다 뛰어나 산소결함자리의 형성을 억제하기 때문이다. Ti의 rf power가 40W일 때 가장 좋은 특성을 나타냈으며, 전류점멸비, 전자이동도, 문턱전압, subthreshold swing이 각각 $10^5$, 2.09 [$cm^2/V{\cdot}s$]. 2.2 [V], 0.492 [V/dec.]로 측정되었다.

• 전자공학회논문지D
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• 제35D권11호
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• pp.70-77
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• 1998

본 논문에서는 nickel/silicon carbide(Ni/SiC) 접합에 의한 Schottky 다이오드를 제작하고, 그 전기적 특성을 조사하였다. Ni/4H-SiC의 경우, 산화막 모서리 단락을 하였을 때 상온에서 973V의 역방향 항복전압이 측정되었으며 이는 모서리 단락되지 않은 Schottky 다이오드의 역방향 항복전압 430V에 비해 매우 높았다. Ni/6H-SiC Schottky 다이오드의 경우, 산화막으로 모서리 단락시켰을 때와 시키지 않았을 때의 역방향 항복전압은 각각, 920V와 160V 였다. 고온에서의 소자 특성도 매우 좋아서 Ni/4H-SiC Schottky 다이오드와 Ni/6H-SiC Schottky 다이오드 모두 300℃까지 전류 특성의 변화가 거의 없었으며 550℃에서도 양호한 정류 특성을 보였다. 상온에서의 Schottky barrier height와 이상인자(ideality factor) 및 specific on-resistance는 Ni/4H-SiC의 경우는 1.55eV, 1.3, 3.6×10/sup -2/Ω·㎠이었으며 Ni/6H-SiC Schottky 다이오드의 경우에 1.24eV, 1.2, 2.6×10/sup -2Ω·㎠/로 나타났다. 실험 결과 Ni/4H-SiC 및 Ni/6H-SiC Schottky 다이오드 모두 고온, 고전압 소자로서 우수한 특성을 나타냄이 입증되었다.

• 한국멀티미디어학회논문지
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• 제7권2호
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• pp.223-230
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• 2004

슈팅게임이라고 하면 사격으로 적을 없애는 모든 형식의 게임을 포함하는 장르라고 할 수 있다. 그것은 오락실에서 흔히 만나는 비행기 슈팅게임에서부터 근래 유행하는 1인칭 슈팅액션게임에 이르기까지 다양한 장르를 포함한다. 이런 점에서 슈팅게임은 모든 게임의 시초라고 할 수 있으며 게임 초창기부터 개발되었고, 아직도 전자오락실이나 PC, 모바일 폰에서 접할 수 있다. 슈팅 게임이 꾸준한 인기를 얻을 수 있는 이유는 간단한 시스템과 인터페이스, 빠른 진행이 남녀노소를 막론한 누구나 게임을 쉽게 즐길 수 있도록 유인하고 있기 때문이다. 요즘 등장하는 슈팅 게임들도 예전과 같은 시스템을 가지고 있으며 게임을 즐기는 부분만큼은 어느 게임보다도 직관적이어서 PC 게임을 접해본 경력을 막론하고 여러 계층의 사람들이 애호하고 있다. 물체의 전-후-좌-우 조정법과 적 비행기의 출현방식, 배경 스크롤 정도의 기법만 익힌다면 가능하므로 게임 제작을 하려는 초보자들이 시도해 볼만한 게임 장르 중 하나이다. 이러한 제작 및 작동의 편의성 때문에 초보개발자들은 슈팅게임의 원초적인 쏘고 맞추는데 생기는 타격감에 대한 내용은 소홀히 하고, 제작해서 완성되고도 타격감의 향상에 따른 박진감, 스릴 등을 효과적으로 전달하지 못하는 것을 느꼈을 것이다. 그러한 타격 감은 그래픽적인 요소와 사운드에서 나타나게 되는데 그런 요소에 관한 것은 잘 만들어진 슈팅 게임을 분석함으로써 일정한 방법이나 수치적인 통계로 나타낼 수 있을 것이다. 본 논문에서는 비행기 슈팅게임 비틀윙과 1945플러스를 비교 분석함으로써 슈팅게임에서의 타격감 향상을 위한 효과적 방향을 제시하려고 한다.

• 한국재료학회지
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• 제11권8호
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• pp.671-678
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• 2001

$RuO_2$ 박막을 전극으로 하여 Pt/Ti/Si 기판 위에 $RuO_2$ /LiPON/$RuO_2$의 다층 구조로 이루어진 전고상의 박막형 마이크로 슈퍼캐패시터를 제작하였다. 전극용 $RuO_2$박막은 반응성 dc 마그네트론 스퍼터를 이용하여 $O_2$/[Ar+$O_2$]비를 증가시키며 성장시켰고, 비정질 LiPON 고체전해질 박막은 순수한 질소분위기 하에서 rf 스퍼터링으로 성장시켰다. 상온에서의 충-방전 측정을 통해 $RuO_2$ 박막의 미세구조에 따라 슈퍼캐패시터의 사이클 특성이 영향을 받는 것을 알 수 있었다. Glancing angle x-ray diffraction(GXRD)과 transmission electron microscopy (TEM) 분석을 통해 산소 유량의 증가가 $RuO_2$박막의 미세 구조의 영향을 주는 것을 알 수 있었고, X-ray photoelectron spectroscopy (XPS) 분석을 통해 산소 유량 비의 증가가 Ru과 산소간의 결합에도 영향을 줌을 알 수 있었다. 또한 사이클 후 슈퍼캐패시터의 TEM 및 AES depth profiling 분석을 통해, 충-방전 시 $RuO_2$와 LiPON과의 계면반응에 의해 형성된 계면 층이 사이클 특성에 영향을 줌을 알 수 있었다.

• 한국재료학회지
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• 제22권7호
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• pp.346-351
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• 2012

$Li_{1+x}Al_xTi_{2-x}(PO_4)_3$(LATP) is a promising solid electrolyte for all-solid-state Li ion batteries. In this study, LATP is prepared through a sol-gel method using relatively the inexpensive reagents $TiCl_4$. The thermal behavior, structural characteristics, fractured surface morphology, ion conductivity, and activation energy of the LATP sintered bodies are investigated by TG-DTA, X-ray diffraction, FE-SEM, and by an impedance method. A gelation powder was calcined at $500^{\circ}C$. A single crystalline phase of the $LiTi_2(PO_4)_3$(LTP) system was obtained at a calcination temperature above $650^{\circ}C$. The obtained powder was pelletized and sintered at $900^{\circ}C$ and $1000^{\circ}C$. The LTP sintered at $900{\sim}1000^{\circ}C$ for 6 h had a relatively low apparent density of 75~80%. The LATP(x = 0.3) pellet sintered at $900^{\circ}C$ for 6 h was denser than those sintered under other conditions and showed the highest ion conductivity of $4.50{\times}10^{-5}$ S/cm at room temperature. However, the ion conductivity of LATP (x = 0.3) sintered at $1000^{\circ}C$ decreased to $1.81{\times}10^{-5}$ S/cm, leading to Li volatilization and abnormal grain growth. For LATP sintered at $900^{\circ}C$ for 6 h, x = 0.3 shows the lowest activation energy of 0.42 eV in the temperature range of room temperature to $300^{\circ}C$.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2000년도 제18회 학술발표회 논문개요집
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• pp.174-174
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• 2000

A strong antiferromagnetic coupling in Fe/Si multilayered films (MLF) had been recently discovered and much consideration has been given to whether the coupling in the Fe/Si MLF system has the same origin as the metal/metal MLF. Nevertheless, the nature of the interfacial ron silicide is still controversial. On one hand, a metal/ semiconductor structure was suggested with a narrow band-gap semiconducting $\varepsilon$-FeSi spacer that mediates the coupling. However, some features show that the nature of coupling can be well understood in terms of the conventional metal/metal multilayered system. It is well known that both magneto-optical (MO) and optical properties of a metal depend strongly on their electronic structure that is also correlated with the atomic and chemical ordering. In this study, the nature of the interfacial regions is the Fe/Si multilayers has been investigated by the experimental and computer-simulated MO and optical spectroscopies. The Fe/Si MLF were prepared by rf-sputtering onto glass substrates at room temperature with the number of repetition N=50. The thickness of Fe sublayer was fixed at 3.0nm while the Si sublayer thickness was varied from 1.0 to 2.0 nm. The topmost layer of all the Fe/Si MLF is Fe. In order to carry out the computer simulations, the information on the MO and optical parameters of the materials that may constitute a real multilayered structure should be known in advance. For this purpose, we also prepared Fe, Si, FeSi2 and FeSi samples. The structural characterization of Fe/Si MLF was performed by low- and high -angle x-ray diffraction with a Cu-K$\alpha$ radiation and by transmission electron microscopy. A bulk $\varepsilon$-FeSi was also investigated. The MO and optical properties were measured at room temperature in the 1.0-4.7 eV energy range. The theoretical simulations of MO and optical properties for the Fe/Si MLF were performed by solving exactly a multireflection problem using the scattering matrix approach assuming various stoichiometries of a nonmagnetic spacer separating the antiferromagnetically coupled Fe layers. The simulated spectra of a model structure of FeSi2 or $\varepsilon$-FeSi as the spacer turned out to fail in explaining the experimental spectra of the Fe/Si MLF in both intensity and shape. Thus, the decisive disagreement between experimental and simulated MO and optical properties ruled out the hypothesis of FeSi2 and $\varepsilon$-FeSi as the nonmagnetic spacer. By supposing the spontaneous formation of a metallic ζ-FeSi, a reasonable agreement between experimental and simulated MO and optical spectra was obtained.

• 한국자기학회지
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• 제20권3호
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• pp.106-113
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• 2010

비가압 상태에서 혈압 및 맥박을 정확하게 측정한 값를 얻기 위하여 안정시 휴대성과 소형화가 가능한 자성 홀소자를 이용한 손목 착용형 맥진기의 시제품을 개발하였다. 본 시제품을 이용하여 맥진파를 분석한 13명의 임상시험 데이터로 상관인자를 정하여 혈압추정 알고리즘의 회귀식을 구하였다. 5초간 비가압 맥진기로 맥진파를 수집한 혈압추정값과 전자혈압계나 수은혈압계로 측정한 혈압값을 비교하였다. 비가압 맥진기로 추정한 최고혈압과 최저혈압의 표준편차는 혈압국제규격 허용치 범위 안에 있는 12.1과 5.9로 각각 나타났다.

• 보건교육건강증진학회지
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• 제32권4호
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• pp.79-92
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• 2015

Objectives: The purpose of this study is to identify the trends of jjok-bang research based on the perspective of Community-Based Participatory Research and Social Ecological Model and to provide information for future public health interventions, policy designs, and policy implementations. Methods: Studies used in the systematic review are published from 1999 to 2014 and searched using key words such as 'jjok-bang' and 'single room occupancy' using domestic and international electronic databases. However, there were no studies from abroad published during this period. Search in domestic databases such as KCI, KISS, RISS generated 119 studies. In this paper, 20 cases which meet the criteria of the systematic review were included in the final analysis. Results: The contents of research included are the life of jjok-bang inhabitants(9 cases), the demand for welfare services(4 cases) and welfare need(2 cases), mental health(1 cases), and the history of jjok-bang formation(4 cases). Fourteen cases of empirical study were analyzed focusing Community-Based Participatory Research and Social Ecological Model. Some of research was carried out forming a partnership with various community partners and this trend increased since 2008. There are high frequency of intrapersonal level and interpersonal level studies. However, studies looking at the organization, community or policy level were relatively few. Conclusions: Future studies of jjok-bang area should consider the various social determinants which affect the health delivery system, community organization and policies, as well as individual or community level.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2012년도 춘계학술발표대회
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• pp.70.1-70.1
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• 2012

In-situ X-ray photoelectron spectroscopy (XPS) and infrared (IR) spectroscopy studies of SOFC cathode materials will be discussed in this presentation. The mixed conducting perovskites (ABO3) containing rare and alkaline earth metals on the A-site and a transition metal on the B-site are commonly used as cathodes for solid oxide fuel cells (SOFC). However, the details of the oxygen reduction reaction are still not clearly understood. The information about the type of adsorbed oxygen species and their concentration is important for a mechanistic understanding of the oxygen incorporation into these cathode materials. XPS has been widely used for the analysis of adsorbed species and surface structure. However, the conventional XPS experiments have the severe drawback to operate at room temperature and with the sample under ultrahigh vacuum (UHV) conditions, which is far from the relevant conditions of SOFC operation. The disadvantages of conventional XPS can be overcome to a large extent with a "high pressure" XPS setup installed at the BESSY II synchrotron. It allows sample depth profiling over 2 nm without sputtering by variation of the excitation energy, and most importantly measurements under a residual gas pressure in the mbar range. It is also well known that the catalytic activity for the oxygen reduction is very sensitive to their electrical conductivity and oxygen nonstoichiometry. Although the electrical conductivity of perovskite oxides has been intensively studied as a function of temperature or oxygen partial pressure (Po2), in-situ measurements of the conductivity of these materials in contact with the electrolyte as a SOFC configuration have little been reported. In order to measure the in-plane conductivity of an electrode film on the electrolyte, a substrate with high resistance is required for excluding the leakage current of the substrate. It is also hardly possible to measure the conductivity of cracked thin film by electrical methods. In this study, we report the electrical conductivity of perovskite $La_{0.6}Sr_{0.4}CoO_{3-{\delta}}$ (LSC) thin films on yttria-stabilized zirconia (YSZ) electrolyte quantitatively obtained by in-situ IR spectroscopy. This method enables a reliable measurement of the electronic conductivity of the electrodes as part of the SOFC configuration regardless of leakage current to the substrate and cracks in the film.

• 한국세라믹학회지
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• 제54권3호
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• pp.211-216
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• 2017

ZnO nanopowder was synthesized using a relatively facile and convenient glycol process. ZnO nanopowder was successfully synthesized at temperatures as low as $125^{\circ}C$ using zinc acetate as the Zn source and 1,4-butanediol as the solvent. Then, the effects of water content on the growth process and morphological evolution of ZnO powders were investigated using 1,4-butanediol and water as binary solvent mixtures. Using pure 1,4-butanediol at a temperature above $125^{\circ}C$, the prepared hexagonal ZnO nanopowder exhibited a quasi-spherical shape with average crystalline size of approximately 30 - 50 nm. It is also demonstrated that the morphology of ZnO powders can be controlled by the addition of various water content in 1,4-butanediol. With increasing water content, the morphologies of the ZnO powders changed sequentially from quasi-spherical to hexagonal plate and pyramid, and finally to hexagonal prismatic with a pyramidal tip. A sharp peak centered at 384 nm in the UV region and a weak broad peak in the visible region between 450 and 700 nm were shown in the room temperature PL spectra of the ZnO synthesized using the glycol process, regardless of the addition of water, suggesting that ZnO nanopowders with the best crystallinity were obtained under these conditions.