• Title/Summary/Keyword: Interface energy

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A First Principles Calculation of the Coherent Interface Energies between Group IV Transition Metal Nitrides and bcc Iron (IV족 천이금속 질화물과 bcc Fe간 계면 에너지의 제일원리 연구)

  • Chung, Soon-Hyo;Jung, Woo-Sang;Byun, Ji-Young
    • Korean Journal of Materials Research
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    • v.16 no.8
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    • pp.473-478
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    • 2006
  • The coherent interface energies and misfit strain energies of Fe/XN (X=Ti, Zr, Hf) systems were calculated by first principles method. The interface energies in Fe/TiN, Fe/ZrN and Fe/HfN systems were 0.343, 0.114, and 0.030 $J/m^2$, respectively. Influence of bond energy was estimated using the discrete lattice plane/nearest neighbor broken bond(DLP/NNBB) model. It was found that the dependence of interface energy on the type of nitride was closely related to changes of the bond energies between Fe, X and N atoms before and after formation of the Fe/XN interfaces. The misfit strain energies in Fe/TiN, Fe/ZrN, and Fe/HfN systems were 0.239, 1.229, and 0.955 eV per 16 atoms(Fe; 8 atoms and XN; 8 atoms). More misfit strain energy was generated as the difference of lattice parameters between the bulk Fe and the bulk XNs increased.

Determination of Energy Distribution of Interface State Density in the MNOS Memory Device (MNOS 기억소자의 계면상태밀도의 에너지 분포의 결정)

  • 한태현;강창수;박종하;서광열
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1988.10a
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    • pp.1-4
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    • 1988
  • The high frequency and quasi-state C-V curves were measured to determine the interface state density in MNOS devices. Berglund method was appropriate for determination of energy distribution of interface state density all over the energy gap. Applying Vg vs Øs relation by Berlund method to comparison-analysis method of the high-frequency and quasi-static C-V curves, we were able to determine the energy distribution by only measured C-V curves without theoretical C-V curves. The interface state density near the conduction band was high at lower temperature than room temperature.

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A Study on the Characteristics of Molecular Motions on a Liquid-Vapor Interface by a Molecular Dynamics Method (분자동역학법에 의한 기액계면 분자의 운동특성에 관한 고찰)

  • Kim Hye-Min;Park Kweon-Ha;Choi Hyun-Kue;Choi Soon-Ho
    • Journal of Advanced Marine Engineering and Technology
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    • v.29 no.1
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    • pp.34-41
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    • 2005
  • An experimental study of molecular motions on a liquid-vapor interface is limited due to micro-scale characteristics of a system with an angstrom or a nanometer size Therefore, in recent, many studies for micro-scale systems have been conducted by a computer simulation because it is free from experimental limitations. In this study, through the molecular dynamic (MD) method. molecular behavior was clarified on a liquid-vapor interface and a criterion to distinguish between liquid and vapor was suggested by a potential energy and the number of neighboring molecules. At an interface. the potential energy of a molecule was increased but the number of neighboring molecules was decreased when the molecule moved into a vapor region from a liquid region, and vice versa.

The effect of interfacial layer thickness on the interface dipole energy in $O_2$ plasma treated metal/organic interface

  • Kim, Soo-Young;Lee, Jong-Lam
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.115-117
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    • 2009
  • Interface dipole energies between interfacial layers with different thicknesses coated on indium tin oxides (ITOs) and 4,4'-bis[N-(1-naphtyl)-N-phenyl-amino]biphenyl are determined. After $O_2$ plasma treatment on thick-metal (>4 nm) coated ITO, the work function and interface dipole energy increased. In thin-metal (< 2 nm) coated ITO, no change in the interface dipole energy was found though the work function increased. Thus, the $O_2$ plasma treated thin (< 2 nm) interfacial layer reduced the hole injection barrier.

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A STUDY ON CANCER CELL INVASION WITH A THREE-DIMENSIONAL DYNAMIC MULTI-PHYSICS MODEL (3차원 동적 다중물리 모델 기반 암세포 증식과정 예측기술 개발)

  • Song, J.;Zhang, L.;Kim, D.
    • 한국전산유체공학회:학술대회논문집
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    • 2010.05a
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    • pp.556-561
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    • 2010
  • This paper proposes a three-dimensional haptotaxis model to simulate the migration of the population of cancer cells. The invasion of the cancer cells relates with the hapto- and the effect of the energy between cells and (ECM). The diffuse interface model is employed, which incorporates haptotaxis mechanism and interface energies. The semi-implicit Fourier spectral scheme is adopted for efficient complications. The simulation results reveal rich dynamics of cancer cells migration.

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Determination of Steel-concrete Interface Parameters: Me chanical Properties of Interface Parameters (강-콘크리트 계면의 계면상수 결정 : 계면상수의 역학적 성질)

  • Lee, Ta;Joo, Young-Tae;Lee, Yong-Hak
    • Journal of the Korea Concrete Institute
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    • v.21 no.6
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    • pp.781-788
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    • 2009
  • Mechanical properties of steel-concrete interface were evaluated on the basis of experimental observations. The properties included bond strength, unbounded and bonded friction angles, residual level of friction angle, mode I fracture energy, mode II bonded fracture energy and unbonded slip-friction energy under different levels of normal stress, and shape parameters to define geometrical shape of failure envelope. For this purpose, a typical type of constitutive model of describing steel-concrete interface behavior was presented based on a hyperbolic three-parameter Mohr-Coulomb type failure criterion. The constitutive model depicts the strong dependency of interface behavior on bonding condition of interface, bonded or unbounded. Values of the interface parameters were determined through interpretation of experimental results, geometry of failure envelope and sensitivity analysis. Nonlinear finite element analysis that incorporates steel-concrete interface as well as material nonlinearities of concrete and steel were performed to predict the experimental results.

Singular Residual Stresses at Interface of Compound Cylinders

  • Lee, S.S.;Kim, T.H.;Kim, J.G.;Park, K.W.;Hwang, J.K.
    • Proceedings of the Korean Nuclear Society Conference
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    • 1996.05c
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    • pp.305-310
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    • 1996
  • This paper concerns the cladding residual stresses in a reactor vessel induced during cooling from the manufacturing temperature down to room temperature Finite element results show that very large stress gradients are present at the interface corner and such stress singularity might lead to local yielding or cladding-base metal debonding.

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Design of SECE Energy Harvest Interface Circuit with High Voltage Comparator for Smart Sensor (고전압 비교기를 적용한 스마트 센서용 SECE 에너지 하베스트 인터페이스 회로 설계)

  • Seok, In-Cheol;Lee, Kyoung-Ho;Han, Seok-Bung
    • The Journal of the Korea institute of electronic communication sciences
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    • v.14 no.3
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    • pp.529-536
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    • 2019
  • In order to apply a piezoelectric energy harvester to a smart sensor system, an energy harvest interface circuit including an AC-DC rectifier is required. In this paper, we compared the performance of full bridge rectifier, which is a typical energy harvester interface circuit, and synchronous piezoelectric energy harvest interface circuit by using board-level simulation. As a result, the output power of a synchronous electric charge extraction(: SECE) circuit is about four times larger than that of the full bridge rectifier, and there is little load variation. And a high voltage comparator, which is essential for the SECE circuit for the piezoelectric energy harvester with an output voltage of 40V or more, was designed using 0.35 um BCD process. The SECE circuit using the designed high-voltage comparator proved that the output power is 427 % higher than the FBR circuit.

Data Management and Communication Networks for Man-Machine Interface System in Korea Advanced Liquid MEtal Reactor : Its Functionality and Design Requirements

  • Cha, Kyung-Ho;Park, Gun-Ok;Suh, Sang-Moon;Kim, Jang-Yeol;Kwon, Kee-Choon
    • Proceedings of the Korean Nuclear Society Conference
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    • 1998.05a
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    • pp.291-296
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    • 1998
  • The DAta management and Communication NETworks (DACONET), Which it is designed as a subsystem for Man-Machine Interface System of Korea Advanced LIquid MEtal Reactor(KALIMER MMIS) and advanced design concept is approached, is described. The DACONET has its roles of providing the real-time data transmission and communication paths between MMIS systems, providing the quality data for protection, monitoring and control of KALIMER and logging the static and dynamic behavioral data during KALIMER operation. The DACONET is characterised as the distributed real-time system architecture with high performance, Future direction, in which advanced technology is being continually applied to Man-Machine interface System Development of Nuclear Power Plants, will be considered for designing data management and communication networks of KALIMER MMIS

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Energy-efficient Real-time Computing by Utilizing Heterogenous Wireless Interfaces of the Smart Mobile Device in Small-IoT Environments (Small-IoT 환경에서 이기종 네트워크를 활용한 스마트 모바일 단말의 에너지 효율적 실시간 컴퓨팅 기법)

  • Lim, Sung-Hwa
    • Journal of the Semiconductor & Display Technology
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    • v.20 no.3
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    • pp.108-112
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    • 2021
  • For smart mobile devices, the wireless communication module is one of the hardware modules that consume the most energy. If we can build a multi-channel multi-interface environment using heterogeneous communication modules and operate them dynamically, data transmission performance can be highly improved by increasing the parallelism. Also, because these heterogeneous modules have different data rates, transmission ranges, and power consumption, we can save energy by exploiting a power efficient and low speed wireless interface module to transmit/receive sporadic small data. In this paper, we propose a power efficient data transmission method using heterogeneous communication networks. We also compared the performance of our proposed scheme to a conventional scheme, and proved that our proposed scheme can save energy while guaranteeing reasonable data delivery time.