• 제목/요약/키워드: electronic structures

검색결과 1,785건 처리시간 0.029초

망목구조 변화에 따른 에폭시 복합게료의 유전 특성에 관한 연구 (A Study on The Dielectric Characteristics in EPOXY Composites due to Variation of Network Structures)

  • 손인환;이덕진;심종탁;김명호;김경환;최벙옥;김재환
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1996년도 춘계학술대회 논문집
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    • pp.202-205
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    • 1996
  • In this paper it is researched a relation between network structures and electrical properties - especially dielectric characteristics with changing of network structure. It is resulted that the specimens which have single network structures have smaller dielectric loss than SIN specimens but have relatively larger dependency to variation of temperature and frequency. For that reason formation of structures is attained by introducing of SIN to insulating materials. therefore it is counted that introduction of multiple structure including SIN is necessary to improve heat proof and electrical properties.

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소규모 구조물의 안전진단을 위한 무선 센서 네트워크 (Wireless Sensor Network for Health & Safety Monitoring of Small Sized Structures)

  • 맹주상;김일환
    • 전기학회논문지
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    • 제67권8호
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    • pp.1099-1105
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    • 2018
  • Wireless sensor networks have been shown to be an effective method for health monitoring of civil structures. In this paper a wireless strain sensor system which will allow easier collection of accurate strain signals in small sized structures is described. The experiment result shows that the developed wireless sensor system and the proposed network system are fit for health & safety monitoring and control of structures.

A Study of Mg Capping Inside p-tert-butylcalix[4]arene Adsorbed on a Ge(100) Surface

  • Shin, Minjeong;Lee, Myungjin;Lee, Hangil
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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    • pp.135-135
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    • 2013
  • The electronic and adsorption structures of Mg and p-tert-butylcalix[4]arene (p-TBCA) adsorbed onto a Ge(100) surface under a variety of sample conditions were characterized using high-resolution photoemission spectroscopy (HRPES) and their corresponding DFT calculation results. Interestingly, after 0.10 ML p-TBCA molecules had been adsorbed onto a Ge(100) surface, subsequent adsorption of a small amount of metallic Mg (~0.10 ML) resulted in the formation of a capped structure inside the pre-adsorbed p-TBCA molecules. The adsorption structures resulting from further deposition of Mg (~0.50 ML) onto the Ge(100) surface were monitored based on the surface charge state and Mg 2s core level spectrum. Work function measurements clearly indicated the electronic structures of the Mg and p-TBCA adsorbed onto the Ge(100) surface. Moreover, we confirmed that three different adsorption structures are experimentally favorable at room temperature through DFT calculation results.

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A method of optimum design based on reliability for antenna structures

  • Chen, Jianjun;Wang, Fanglin;Sun, Huaian;Zhang, Chijiang
    • Structural Engineering and Mechanics
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    • 제8권4호
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    • pp.401-410
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    • 1999
  • A method of optimum design based on reliability for antenna structures is presented in this paper. By constructing the equivalent event, the formula is derived for calculating the reliability of reflector accuracy of antenna under the action of random wind load. The optimal model is developed, in which the cross sectional areas of member are treated as design variables, the structure weight as objective function, the reliability of reflector accuracy and the strength or stability of structural elements as constraints. The improved accelerated convergence gradient algorithm developed by the author is used. The design results show that the method in this paper is feasible and effective.

Tight-binding Electronic Structure Study of the β'- and β''-Phases of the Organic Conducting Salts (BEDT-TTF)2[(IBr2)0.2(BrICl)0.1(ICl2)0.7]

  • Koo, Hyun-Joo;WhangBo, Myung-Hwan
    • Bulletin of the Korean Chemical Society
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    • 제28권2호
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    • pp.241-245
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    • 2007
  • The electronic structures of the new organic conducting salts, the β'- and β''-phases of (BEDT-TTF)2[(IBr2)0.2(BrICl)0.1(ICl2)0.7], were examined by calculating their electronic band structures, Fermi surfaces and HOMO-HOMO interaction energies using the extended Huckel tight binding method. On the basis of these calculations, we probed why the β'-phase is semiconducting while the β ''-phase is metallic.

Electronic Structures and Physical Properties of the Ordered and Disordered $Ni_2$MnGa Alloy Films

  • Kim, K. W.;Lee, N. N.;Y. Y. Kudryavtsev;Lee, Y. P.
    • 한국진공학회지
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    • 제12권S1호
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    • pp.104-106
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    • 2003
  • In this study, the electronic structures and physical properties of Ni$_2$MnGa alloy films and their dependence on the order-disorder structural transitions were investigated. The results show that the ordered films behave nearly the same as the bulk $Ni_2$MnGa alloy, including the martensitic transformation at 200 K. Unexpectedly, the disordering in $Ni_2$MnGa alloy films does not lead to any appreciable magnetic ordering down to 4 K. An annealing of the disordered films restores the ordered structure with an almost full recovery of the magnetic and the transport properties of the ordered $Ni_2$MnGa alloy films. A possible explanation of the disappearance of magnetic moment in the disordered film is given by using the ab initio first-principles electronic-structure calculations.

표면 Texturization을 가진 Photovoltaic Device 내부의 열 분포 특성에 관한 연구 (A Study of the Thermal Characteristics of a Photovoltaic Device with Surface Texturization)

  • 정지철;문경숙;구상모
    • 한국전기전자재료학회논문지
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    • 제23권7호
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    • pp.509-512
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    • 2010
  • The thermal distribution of 2D and 3D p-n photovoltaic diode structures with and without surface texturing has been studied. By analysis of the numerical simulation results of the I-V characteristics and lattice temperature distributions the effect of different texturing structures on the characteristics of silicon p-n photovoltaic devices has been studied systematically. The efficiency of the device having surface texturing shows more than ~2% enhancement compared to the reference devices which did not have texturing. In addition, the effect of the density of the texturing groove has been studied and it has been confirmed that the texturing structure not only improves the light trapping but also plays an important role in the heat radiation.

Supersonic Free Jet and Ab initio Studies of Electronic-Vibrational Structures of Fluorene

  • 부봉현;최영식;김택수;강성권;김재룡
    • Bulletin of the Korean Chemical Society
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    • 제16권4호
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    • pp.341-344
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    • 1995
  • Laser-induced fluorescence (LIF) excitation spectra were measured for fluorene (FR) cooled in pulsed supersonic expansions of He in the range 283.7-296.7 nm. Ab initio studies of FR have also been carried out for determining the electronic and vibrational structures by using the standard 3-21G basis sets. In the LIF excitation spectra of FR, highly resolved vibronic bands are observed having the band origin of 33,791 cm-1. The vibrational bands above the electronic origin were assigned on the basis of the well-characterized electronic vibrational bands reported previously and of normal modes of vibrations derived by our HF/3-21G calculations.