• 제목/요약/키워드: Electronic states

검색결과 864건 처리시간 0.031초

버퍼와 채널 상태를 고려한 적응형 링크선택 방안의 성능 분석 (Performance Analysis of Adaptive Link-Selection Scheme considering Buffer and Channel State Information)

  • 김휴준;정영욱
    • 전기전자학회논문지
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    • 제22권2호
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    • pp.402-407
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    • 2018
  • 효과적인 링크선택은 릴레이 네트워크의 성능을 결정짓는 중요한 기술적 이슈이다. 본 논문은 릴레이 버퍼의 상태와 릴레이 링크 상태 뿐만 아니라 유저 버퍼의 상태까지 고려한 링크선택 방안을 제시하고 그 성능을 분석하기 위한 마코프 체인 기반의 분석 모델을 제시하였다. 이를 통해 릴레이 네트워크의 쓰루풋과 지연 성능을 평가하였다.

A Fractional Model Reduction for T-S Fuzzy Systems with State Delay

  • Yoo Seog-Hwan;Choi Byung-Jae
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • 제6권3호
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    • pp.184-189
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    • 2006
  • This paper deals with a fractional model reduction for T-S fuzzy systems with time varying delayed states. A contractive coprime factorization of time delayed T-S fuzzy systems is defined and obtained by solving linear matrix inequalities. Using generalized controllability and observability gramians of the contractive coprime factor, a balanced state space realization of the system is derived. The reduced model will be obtained by truncating states in the balanced realization and an upper bound of model approximation error is also presented. In order to demonstrate efficacy of the suggested method, a numerical example is performed.

스핀편극 각도분해 광전자 분광학을 이용한 자성연구 (Spin-Polarized Angle-Resolved Photoemission Spectroscopy Study of Magnetism)

  • 김형도
    • 한국자기학회지
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    • 제22권6호
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    • pp.228-233
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    • 2012
  • 한 고체의 자성은 원자가 전자의 양자역학적 상태에 의해 결정되는데, 스핀편극 각도분해 광전자 분광학(SP-ARPES)은 고체안의 전자상태를 조사할 수 있는 가장 강력한 방법으로 어떤 물질의 자성을 이해하는 데에 많은 도움을 준다. 본고에서는 SP-ARPES 방법에 대한 간락한 소개와 이를 통해 얻을 수 있는 물리적 정보에 대해 기술한다.

Fluorine-19 NMR Spectroscopic Studies of Phenyl-fluorinated Iron Tetraarylporphyrin Complexes

  • Song, Byung-Ho;Yu, Byung-soo
    • Bulletin of the Korean Chemical Society
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    • 제24권7호
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    • pp.981-985
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    • 2003
  • Fluorine-19 NMR solution measurements have been made for various phenyl-fluorinated iron porphyrin complexes. Large chemical shifts for phenyl fluorine signals of iron(III) and iron(II) are observed, and these signals are sensitive to electronic structure. The chemical shift differences in ortho-phenyl fluorine signals between high-spin ferric and low-spin ferric tetrakis(pentafluorophenyl)porphyrins are approximately 40 ppm, whereas the differences are approximately 7 ppm between high- and low-spin states of ferrous tetrakis(pentafluorophenyl)porphyrin complexes. Analysis of fluorine-19 isotropic shifts for the iron(III) tetrakis(pentafluorophenyl) porphyrin using fluorine-19 NMR indicates there is a sizable contact contribution at the ortho-phenyl fluorine ring position. Large phenyl fluorine-19 NMR chemical shift values, which are sensitive to the oxidation and spin states, can be utilized for identification of the solution electronic structures of iron(III) and iron(II) porphyrin complexes.

Extraction of Exact Layer Thickness of Ultra-thin Gate Dielectrics in Nanoscaled CMOS under Strong Inversion

  • Dey, Munmun;Chattopadhyay, Sanatan
    • JSTS:Journal of Semiconductor Technology and Science
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    • 제10권2호
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    • pp.100-106
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    • 2010
  • The impact of surface quantization on device parameters of a Si metal oxide semiconductor (MOS) capacitor has been analyzed in the present work. Variation of conduction band bending, position of discrete energy states, variation of surface potential, and the variation of inversion carrier concentration at charge centroid have been analyzed for different gate voltages, substrate doping concentrations and oxide thicknesses. Oxide thickness calculated from the experimental C-V data of a MOS capacitor is different from the actual oxide thickness, since such data include the effect of surface quantization. A correction factor has been developed considering the effect of charge centroid in presence of surface quantization at strong inversion and it has been observed that the correction due to surface quantization is crucial for highly doped substrate with thinner gate oxide.

First-Principles Study of the Three Polymorphs of Crystalline 1,1-Diamino-2,2-dinitrotheylene

  • Wu, Qiong;Zhu, Weihua;Xiao, Heming
    • Bulletin of the Korean Chemical Society
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    • 제34권8호
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    • pp.2281-2285
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    • 2013
  • The electronic structure, optical spectra, and thermodynamic properties of the three FOX-7 polymorphs (${\alpha}$, ${\beta}$, and ${\gamma}$) have been studied systematically using density functional theory. The LDA (CA-PZ) and generalized gradient approximation (GGA) (PW91) functions were used to relax the three FOX-7 phases without any constraint. Their density of states and partial density of states were calculated and analyzed. The band gaps for the three phases were calculated and the sequence of their sensitivity was presented. Their absorption coefficients were computed and compared. The thermodynamic functions including enthalpy (H), entropy (S), free energy (G), and heat capacity ($C_p$) for the three phases were evaluated.

First-principles study of the electronic and thermal transport properties of carbon chains

  • Kim, Hu Sung;Park, Min Kyu
    • EDISON SW 활용 경진대회 논문집
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    • 제2회(2013년)
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    • pp.238-239
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    • 2013
  • We studied the thermal and electron properties of covalent one-dimensional (1D) monatomic linear chains of carbon, particularly carbyne. We found the ${\alpha}$-carbyne (Polyyne, alternating single and triple C-C bond co-existing) is more stable than ${\beta}$-carbyne (Equally-spaced based on C-C double bond) energetically. As investigation of electron density of states (EDOS), polyyne and cumulene had different electronic characteristic, which corresponding metallic and semiconducting respectively. We also calculate the phonon dispersion, phonon density of states (PDOS) and phonon transmission of carbynes.

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Pr,Eu,Al을 첨가한 SrTiO3 형광체의 발광특성 (Luminescent Properties of SrTiO3 Phosphors doped with Pr,Eu and Al)

  • 박창섭;유일
    • 한국전기전자재료학회논문지
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    • 제20권6호
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    • pp.527-530
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    • 2007
  • [ $SrTiO_3$ ] red phosphors doped with Pr, Er and Al were synthesized by solid state reaction method. Three emission peaks in photoluminescence spectra of the $SrTiO_3:Eu$ Phosphors were observed at 583 nm, 610 nm and 685 nm. The emission peaks in the $SrTiO_3:Eu$ phosphors were associated with charge-transfer states. The decrease of photoluminescence intensity in $SrTiO_3:Eu,Al$ phosphors with doping Al ions was interpreted by the change of charge-transfer states.

p-채널 po1y-Si TFT 소자의 Hot-Carrier효과에 관한 연구 (A Study on the Hot-Carrier Effects of p-channel poly-Si TFT)

  • 진교원;박태성;이제혁;백희원;변문기;김영호
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1997년도 추계학술대회 논문집
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    • pp.266-269
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    • 1997
  • Hot carrier effects as a function of bias stress time and bias stress conditions were syste-matica1ly investigated in p-channel po1y-Si TFT's fabricated on the quartz substrate. The device degradation was observed for the negative bias stress. After positive bias stressing, Improvement of electrical characteristic except for subthreshold slope was observed. It was found that these results were related to the hot carrier injection into the gate oxide and interface states at the poly-Si/SiO$_2$interface rather than defects states generation under bias stress.

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미국 Virginia Tech 공학교육과에서의 공학교육 혁신 (Innovation of Engineering Education in Department of Engineering Education at Virginia Tech in the United States)

  • 김진수
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2007년도 추계학술대회 논문집
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    • pp.504-505
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    • 2007
  • In 2004, a department of engineering education was established at Virginia Tech and Purdue university in the United States. Innovation of engineering education for improving the quality of engineering college education has been progressing. Content of subject of engineering exploration was developed newly for engineering college freshmen. And, effect of a sustainable energy design project on academic achievement for engineering freshmen at Virginia Tech in 2006 was researched. The project was performed throughout a 6 weeks period with one by 50 minutes lecture by professor and one 90 minutes workshop by TAs (Teaching Assistants) every week. To analyze the data, statistical package SPSS (ver. 15.0) was used. In responses to an open-ended question about freshmen students' perceptions of their improvement in design skills, the 3 most identified skills were teamwork, design process, knowledge. In, Korea, an innovation relating to engineering curriculum, facility, instructional strategy and so on will be required.

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