• Title/Summary/Keyword: migration model

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The Effect of Dislocation Pipe Diffusion on Electro-Migration-Induced Breakdown in an FCC Structure (면심입방구조에서 Electro-Migration-Induced Breakdown에 대한 전위파이프 확산의 영향)

  • 이득용
    • Journal of the Korean Ceramic Society
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    • v.28 no.11
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    • pp.878-884
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    • 1991
  • The mobility and diffusivity in an edge dislocation in an FCC crystal formed by the removal of one half of a (100) plane were evaluated in an applied field by analyzing a vacancy tight binding model using Stark's matrix technique. A model of an edge dislocation in an FCC crystal was constructed for a [100] Burgers vector where vacancy transport along the edge dislocation in an FCC crystal was constructed for a [100] Burgers vector where vacancy transport along the edge of the extrac half plane of ions was considered. The model considered a tight binding approximation of the vacancy to the compressed region of the core and carried the calculation to the limit of an infinite length of dislocation. The diffusivity and the ratio of mobility to diffusivity were found to increase without bounds in the limit where the correlation factor becomes zero. In contrast, as the correlation factor became unity, the diffusivity became zero and the ratio of mobility to diffusivity became unity associated with the uncorrelated limit of 1/kT. This implied that the phenomenon was not unique to the crystal structure but was unique to edge dislocations with vacancy tight binding.

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Distributed Genetic Algorithm using aster/slave model for the TSP (TSP를 위한 마스터/슬레이브 모델을 이용한 분산유전 알고리즘)

  • Jung-Sook Kim
    • Journal of the Korea Computer Industry Society
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    • v.3 no.2
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    • pp.185-190
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    • 2002
  • As the TSP(Traveling Salesman Problem) belongs to the class of NP-complete problems, various techniques are required for finding optimum or near optimum solution to the TSP. This paper designs a distributed genetic algorithm in order to reduce the execution time and obtain more near optimal using multi-slave model for the TSP. Especially, distributed genetic algorithms with multiple populations are difficult to configure because they are controlled by many parameters that affect their efficiency and accuracy. Among other things, one must decide the number and the size of the populations (demes), the rate of migration, the frequency of migrations, and the destination of the migrants. In this paper, I develop random dynamic migration rate that controls the size and the frequency of migrations. In addition to this, I design new migration policy that selects the destination of the migrants among the slaves

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Experimental Investigation of Consolidation Induced Contaminant Transport Using a Centrifuge

  • Horace, Moo-Young;Kim, Tae-Hyung
    • Journal of Soil and Groundwater Environment
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    • v.8 no.1
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    • pp.35-41
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    • 2003
  • Laboratory procedures are available for estimating contaminant migration from sediment into caps by diffusion, but diffusion may not be the major process affecting capping effectiveness. Movement of contaminated pore water from sediment into caps due to sediment consolidation during and after cap placement may be much more significant than contaminant diffusion into caps. To verify this phenomenon, model tests were conducted by utilizing a research centrifuge. In this study, test was modeled for 22.5 hours at 100 g, which modeled a contaminant migration time of 25 years for a prototype that was 100 times larger than the centrifuge model. Centrifuge test results illustrate that advection and dispersion due to consolidation are dominating the migration of contaminants.

A Numerical Model for Nuclide Migration in the Far-field of the Repository (처분장 Far-field에서의 핵종이동 수치 모델)

  • Lee, Youn-Myoung;Lee, Han-Soo;Park, Heui-Joo;Cho, Won-Jin;Han, Kyong-Won;Park, Hun-Hwee
    • Nuclear Engineering and Technology
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    • v.21 no.4
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    • pp.267-276
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    • 1989
  • A numerical model for nuclide migration through fractured rock media has been developed. Nuclide transport with groundwater in rock fissures and the diffusion of nuclides into rock matrix are considered one-dimensionally . In the safety assessment of the repository for radioactive waste, this one-dimensional model by the finite-difference scheme, which enables us not only to use more realistic boundary conditions but also to model the nonhomogeneous rock medium as the multilayered media, can be used effectively with the analytical mode. The solution by the numerical model will be verified analytically, and then extended to the double-layered rock medium transport model.

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Effects of TESTIN Gene Expression on Proliferation and Migration of the 5-8F Nasopharyngeal Carcinoma Cell Line

  • Zhong, Zhun;Zhang, Fei;Yin, Shu-Cheng
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.6
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    • pp.2555-2559
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    • 2015
  • Purpose: To investigate effects of the TESTIN (TES) gene on proliferation and migration of highly metastatic nasopharyngeal carcinoma cell line 5-8F and the related mechanisms. Materials and Methods: The target gene of human nasopharyngeal carcinoma cell line 5-8F was amplified by PCR and cloned into the empty plasmid pEGFP-N1 to construct a eukaryotic expression vector pEGFP-N1-TES. This was then transfected into 5-8F cells. MTT assays, flow cytometry and scratch wound tests were used to detect the proliferation and migration of transfected 5-8F cells. Results: A cell model with stable and high expression of TES gene was successfully established. MTT assays showed that the OD value of 5-8F/TES cells was markedly lower than that of 5-8F/GFP cells and 5-8F cells (p<0.05). Flow cytometry showed that the apoptosis rate of 5-8F/TES cells was prominently increased compared with 5-8F/GFP cells and 5-8F cells (p<0.05). In vitro scratch wound assays showed that, the width of the wound area of 5-8F/TES cells narrowed slightly, while the width of the wound area of 5-8F/ GFP cells and 5-8F cells narrowed sharply, suggesting that the TES overexpression could inhibit the migration ability. Conclusions: TES gene expression remarkably inhibits the proliferation of human nasopharyngeal carcinoma cell line 5-8F and reduces its migration in vitro. Thus, it may be a potential tumor suppressor gene for nasopharyngeal carcinoma.

Flow Lab. : Flow Visualization and Simulation (핵종이동 가시적 현상관찰및 수치모사)

  • Park Chung-Kyun;Cho Won-Jin;Hahn Pi1-Soo
    • Proceedings of the Korean Radioactive Waste Society Conference
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    • 2005.11a
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    • pp.134-142
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    • 2005
  • The experimental setups for flow visualization and processes identification in laboratory scale (so cal led Flow Lab.) has developed to get ideas and answer fundamental questions of flow and migration in geologic media. The setup was made of a granite block of $50{\times}50cm$ scale and a transparent acrylate plate. The tracers used in this experiments were tritiated water, anions, and sorbing cations as well as an organic dye, eosine, to visualize migration paths. The migration plumes were taken with a digital camera as a function of time and stored as digital images. A migration model was also developed to describe and identify the transport processes. Computer simulation was carried out not only for the hydraulic behavior such as distributions of pressure and flow vectors in the fracture but also for the migration plume and the elution curves.

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Fast numerical methods for marine controlled-source electromagnetic (EM) survey data based on multigrid quasi-linear approximation and iterative EM migration (다중격자 준선형 근사 및 반복적 전자탐사 구조보정법에 기초한 해양 인공송신 전자탐사 자료의 빠른 수치해석 기법)

  • Ueda, Takumi;Zhdanov, Michael S.
    • Geophysics and Geophysical Exploration
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    • v.11 no.1
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    • pp.60-67
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    • 2008
  • In this paper we consider an application of the method of electromagnetic (EM) migration to the interpretation of a typical marine controlled-source (MCSEM) survey consisting of a set of sea-bottom receivers and a moving electrical bipole transmitter. Three-dimensional interpretation of MCSEM data is a very challenging problem because of the enormous number of computations required in the case of the multi-transmitter and multi-receiver data acquisition systems used in these surveys. At the same time, we demonstrate that the MCSEM surveys with their dense system of transmitters and receivers are extremely well suited for application of the migration method. In order to speed up the computation of the migration field, we apply a fast form of integral equation (IE) solution based on the multigrid quasi-linear (MGQL) approximation which we have developed. The principles of migration imaging formulated in this paper are tested on a typical model of a sea-bottom petroleum reservoir.

Prestack Reverse Time Migration for Seismic Reflection data in Block 5, Jeju Basin (제주분지 제 5광구 탄성파자료의 중합전 역시간 구조보정)

  • Ko, Chin-Surk;Jang, Seong-Hyung
    • Economic and Environmental Geology
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    • v.43 no.4
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    • pp.349-358
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    • 2010
  • For imaging complex subsurface structures such as salt dome, faults, thrust belt, and folds, seismic prestack reverse-time migration in depth domain is widely used, which is performed by the cross-correlation of shot-domain wavefield extrapolation with receiver-domain wavefield extrapolation. We apply the prestack reverse-time migration, which had been developed at KIGAM, to the seismic field data set of Block 5 in Jeju basin of Korea continental shelf in order to improve subsurface syncline stratigraphy image of the deep structures under the shot point 8km at the surface. We performed basic data processing for improving S/N ratio in the shot gathers, and constructed a velocity model from stack velocity which was calculated by the iterative velocity spectrum. The syncline structure of the stack image appears as disconnected interfaces due to the diffractions, but the result of the prestack migration shows that the syncline image is improved as seismic energy is concentrated on the geological interfaces.

Numerical Study on Fine Migration in Geo-materials (지반내 세립토 유동에 대한 수치해석적 연구)

  • Shin, Hosung
    • Journal of the Korean Geotechnical Society
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    • v.34 no.11
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    • pp.33-41
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    • 2018
  • Soil internal erosion is a phenomenon in which fines attached to the solid skeleton are detached by fluid flow, and this continuous fine migration weakens the hydro-mechanical characteristics of the ground structure. This paper proposed governing equations for fine migration in pore spaces and its related scheme for the numerical analysis. Phase diagram for fine particles includes three different states: detached fines in the liquid phase ($c_e$), attached fines in the solid phase (${\sigma}_a$), and pore-clogged fines in the solid phase (${\sigma}_s$). Numerical formulations for finite element method are developed based on the hydraulic governing equations of pore fluid and fine migration. This study proposed a method of estimating model parameters for fine detachment, attachment, and clogging from 1D erosion experiments. And it proposed an analytical formula for hydraulic permeability function considering fine clogging. Numerical analysis of the previous erosion test developed the numerical scheme and verified the adequacy of fine migration models.