• 제목/요약/키워드: effective diffusion

검색결과 844건 처리시간 0.032초

고효율기기의 보급확산을 고려한 전력수요관리 모니터링시스템의 방법론 개발 (Development of DSM(Demand Side Management) Monitoring Methodology Considering the Diffusion Process of High Efficient End-Use Appliances)

  • 황성욱;김발호;김정훈;장승찬;김창섭
    • 대한전기학회논문지:전력기술부문A
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    • 제48권8호
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    • pp.941-950
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    • 1999
  • This paper presents a DSM monitoring methodology that is able to evaluate the impact of DSM programs especially focused on the strategic conservation i.e. the enhancement of end-use energy efficiency. For an effective assessment of DSM programs, it is foremost necessary to examine the market characteristics on the specific end-use appliance according to the customer's adoption of DSM programs. The proposed monitoring methodology contains a diffusion process of high efficient end-uses considering major factors of DSM impact such as, price, reference capacity, forecasted capacity and lifetime of end-use appliances. Case studies show the projection of power reductions and energy savings resulted from DSM monitoring in order to diagnose the current status properly and provide a baseline of DSM policy and analysis.

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$CF_4$ 기체의 MCS-BEq 알고리즘에 의한 전자에너지 분포함수 (Electron Energy Distribution Function in $CF_4$ Gas used by MCS-BE Algorithm)

  • 박재세;김상남;김일남
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2002년도 학술대회 논문집 전문대학교육위원
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    • pp.102-105
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    • 2002
  • In this paper, the electron transport characteristics in $CF_4$ has been analysed over the E/N range 1${\sim}$300 [Td] by a two-term approximation Boltzmann equation method and by a Monte Carlo simulation. The motion has been calculated to give swarm parameters for the electron drift velocity, longitudinal diffusion coefficient, the ratio of the diffusion coefficient to the mobility, electron ionization and attachment coefficients, effective ionization coefficient, mean energy, collision frequency and the electron energy distribution function. The swarm parameter from the swarm study are expected to serve as a critical test of current theories of low energy electron scattering by atoms and molecules, in particular, as well as crucial information for quantitative simulations of weakly ionized plasmas.

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금속후 어닐링 방법이 Si-$SiO_2$ 계면 전하 농도에 미치는 영향 (Effect of Post-Metallization Anneal (PMA) on Interface Trap Density of Si-$SiO_2$)

  • 정종완
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2007년도 추계학술대회 논문집
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    • pp.157-158
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    • 2007
  • Effects of post-metallization anneal (PMA) on interface trap characteristics of Si-$SiO_2$ are studied. The conventional PMA method utilizes forming gas anneal, where 10% hydrogen in nitrogen atmosphere is used. A new PMA method utilizes hydrogen rich PECVD- silicon nitride $(SiN_x)$ film as a hydrogen diffusion source and a out-diffusion blocking layer. It can be shown through charge pumping current measurement that the new PMA is indeed effective to decrease Si-$SiO_2$ interface trap density.

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시뮬레이션에 의한 $CF_4$ 기체의 전자수송특성 (A Study of the Insulation Characteristic in $CF_4$ Gas)

  • 김상남;황청호
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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    • pp.468-469
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    • 2007
  • In this paper, the electron transport characteristics in $CF_4$ has been analysed over the E/N range 1~300[Td] by a two-tenn approximation Boltzmann equation method and by a Monte Carlo simulation. The motion has been calculated to give swarm parameters for the electron drift velocity, longitudinal diffusion coefficient, the ratio of the diffusion coefficient to the mobility, electron ionization and attachment coefficients, effective ionization coefficient, mean energy, collision frequency and the electron energy distribution function. The swarm parameter from the swarm study are expected to serve as a critical test of current theories of low energy electron scattering by atoms and molecules, in particular, as well as crucial information for quantitative simulations of weakly ionized plasmas.

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고정화 세포에 의한 Fructo-oligosaccharides 생산 반응메카니즘에서 물질전달 영향에 대한 수학적 모델 (Modeling the effect of mass transfer on the kinetics of fructo-oligosaccharide production by immobilized cells)

  • 윤종원;전영중이민규송승구
    • KSBB Journal
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    • 제8권3호
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    • pp.266-271
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    • 1993
  • Calcium Alginate gel에 고정화된 Aureobasidium pullulans cell을 이용한 fructo-이igosaccharides 생산 반응메카니즘에 있어서 포도당, sucrose 및 fructo-oligosaccharides의 유효확산계수를 구하고, 반응메카니즘에 대한 수학적 모벨을 제안하였다. $770g/\ell$, $860g/\ell$ 의 고농도 당용액에서 이들의 유효확산계수는 $1.2-7.6\times10^{-7}\textrm{cm}^2$/s 범위로 매우 낮은 값을 보였고, 이 결과를 모댈식에서 적용하여 기질농도, bead 크기 및 첨가비율 등을 변화시키면서 실험적으로 검증해 본 결과 실험치와 모델식이 대체로 잘 일하였다.

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건축물의 연기확산 방지 및 제어를 위한 방연구획의 법제화 제안 (Proposal of Legislation of Smoke Compartment for Prevention and Control of Smoke Diffusion in Buildings)

  • 권영진;진승현;김혜원
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2019년도 추계 학술논문 발표대회
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    • pp.96-97
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    • 2019
  • According to building law, there are only regulations on the fire prevention compartments that can perform the function of partial smoke compartment, but the building law management of the smoke compartment for effective smoke diffusion prevention and control is not possible. The lack of control on the smoke compartment such as leakage rate on the penetrating part, and the lack of leakage rate in the design of smoke control of fire safety law resulted in the absence of fundamental safety technology. Therefore, this study seeks to find solutions to domestic problems after reviewing relevant domestic laws and regulations.

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작은 수직관을 흐르는 슬러그 유동의 물질전달 특성에 대한 반경험적 해석 (Semi-Empirical Analysis of the Mass Transfer Characteristics of the Slug Flow in Vertical Mesoscale Tubes)

  • 김동선
    • 설비공학논문집
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    • 제26권8호
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    • pp.366-374
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    • 2014
  • Experimental mass transfer data, which were obtained for the $CO_2$-water slug flows in vertical tubes with 2, 5, and 8mm diameters, were analyzed in comparison with the penetration theory. It was found that a penetration model with molecular diffusion coefficient cannot predict the experimental data accurately. An effective diffusion coefficient, which considers enhancement effect of interfacial waves, was suggested to improve prediction. Another empirical factor was also suggested to consider the effect of non-uniform interface velocity. A modified penetration model was found to be capable of predicting the experimental data reasonably well.

Glucose Diffusion Limiting Membrane Based on Polyethyleneimine (PEI) Hydrogel for the Stabilization of Glucose Sensor

  • Kim, Suk-Joon;Shin, Woonsup
    • Journal of Electrochemical Science and Technology
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    • 제12권2호
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    • pp.225-229
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    • 2021
  • Commercially available continuous glucose sensors require the operation stability for more than two weeks. Typically, the sensor comprises a sensing layer and an over-coating layer for the stable operation inside the body. In the sensing layer, enzymes and mediators are cross-linked together for the effective sensing of the glucose. The over-coating layer limits the flux of glucose and works as a biocompatible layer to the body fluids. Here, we report the simple preparation of the flux-limiting layer by the condensation of polyethyleneimine (PEI), tri-epoxide linker, and trimethylolpropane triglycidyl ether (PTGE). The sensor is constructed by a layer-by-layer drop-coating of the sensing layer containing glucose dehydrogenase and the PEI-derived blocking layer. It is stable for more than 14 days, which is enough for the sensor in the continuous monitor glucose monitoring (CGM) system.

Service life of concrete culverts repaired with biological sulfate-resisting mortars

  • Hyun-Sub, Yoon;Keun-Hyeok, Yang;Nguyen, Van Tuan;Seung-Jun, Kwon
    • Computers and Concrete
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    • 제30권6호
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    • pp.409-419
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    • 2022
  • The purpose of this study is to examine the effectiveness of biological repairing mortars on restoring the structural performance of a sewage culvert deteriorated by sulfate attack. The biological mortars were developed for protecting concrete structures exposed to sulfate attack based on the block membrane action of the bacterial glycocalyx. The diffusion coefficient of sulfate ions in the biological mortars was determined from the natural diffusion cell tests. The effect of sulfate-attack-induced concrete deterioration on the structural performance of culverts was examined by using the moment-curvature relationship predicted based on the nonlinear section lamina approach considering the sulfuric-acid-induced degradation of the structure. Typical analytical assessments showed that biological mortars were quite effective in increasing the sulfate-resistant service life of sewage culverts.

1차원 해석해를 이용한 저투수성 매체에서의 확산에 관한 연구 (One-dimensional Analytical Solutions for Diffusion from a Low-permeability Layer)

  • 장성간;양민준
    • 자원환경지질
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    • 제53권1호
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    • pp.11-21
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    • 2020
  • 본 연구는 대수층과 저투수층이 존재하는 단일시스템에서 trichloroethylene (TCE)과 tetrachloroethylene (PCE)의 거동에 대해 1차원 확산 해석해를 사용하여 저투수층의 농도 분포, 대수층과 저투수층의 경계면에서 확산 선속, 그리고 역확산에 의한 대수층의 오염 지속성을 모델링하였다. 모델링에 사용된 해석해는 이전 연구에서 많이 사용되었던 저투수층의 두께가 무한한 조건의 해석해와 본 연구에서 제시한 저투수층의 두께가 유한한 조건을 고려한 해석해를 모두 사용하였다. 제시된 해석해의 타당성을 평가하기 위해 저투수층의 두께가 무한한 조건의 해석해와 Yang et al.(2015)이 개발한 1차원 확산 해석해의 결과를 Nash-Sutcliffe 유효계수(NSE)로 비교하였다. 저투수층의 농도 분포, 확산 선속, 그리고 대수층의 오염 지속성 등 모든 결과에서 무한한 조건의 해석해를 이용하였을 때 과소평가되는 결과를 나타내었다. 그리고 본 연구에서 제시한 해석해의 결과와 Yang et al. (2015)이 개발한 해석해의 결과는 높은 일치성(NSE = 0.99)을 보였다. 본 연구에서 제시한 해석해를 실제 오염된 부지에 효율적으로 적용하기 위해 유효확산계수, 저투수층의 두께, 그리고 확산된 시간을 이용하여 확산 거리(Zd)라는 용어를 소개하였다. 확산 거리가 0.7 보다 작은 경우 저투수층의 두께가 무한한 조건의 해석해를 사용할 수 있으며, 확산 거리가 0.7 보다 큰 경우 저투수층의 두께가 유한한 확산 해석해를 사용하여야 모델링의 신뢰성을 높일 수 있을 것으로 사료된다.