• Title/Summary/Keyword: Green's function

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An Analysis of the Hydroelastic Response of Large Floating Structures in Oblique Waves (사파중에 놓인 거대 부유체의 응답에 대한 유탄성 해석)

  • In-H. Sim;Jae-D. Yoon;Hang-S. Choi
    • Journal of the Society of Naval Architects of Korea
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    • v.36 no.3
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    • pp.83-92
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    • 1999
  • In this paper, the fluid-structure interaction of large floating structures has been rigorously analyzed and the shear effect on the structural deformation has been investigated in oblique waves. A constant panel method(CPM) based on the Green function method is implemented for computing the hydrodynamic pressure, while a finite element method(FEM) is applied for the structural response based on the Mindlin plate theory with including shear deformation. In order to validate the method, we compared numerical results with experimental ones of Mega Float carried out by Yago & Endo in head waves. General behavior shows good agreement but the local displacement at the ends is slightly different. The numerical results show that the radiation pressure due to the fluid-structure interaction is locally larger than that of wave excitation and mooring devices greatly reduce the response. It is observed that the shear effects among the total deformation constitutes about 4% in the case of Mega Float in oblique waves.

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A Study on the Transport­oriented Development(TOD) and Policy Implication considering Climate Change: Focused on Dublin Public Transport Policy, Ireland (기후변화를 고려한 대중교통지향적 도시개발(TOD)과 정책적 시사점: 아일랜드, 더블린 대중교통정책을 중심으로)

  • Oh, Eun-Yeol
    • Journal of Industrial Convergence
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    • v.17 no.4
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    • pp.45-51
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    • 2019
  • In this study, climate change considerations are an important measure to create a resilient city that conforms to the principle of sustainable development that balances the economic, social and environmental harmony of a country or city and can preserve its size, function and characteristics to the maximum extent possible. In this regard, the public transportation system being built and operated in Dublin City, Ireland, illustrates the city's system through green traffic. Therefore, based on the urban-based conditions equipped by Dublin, Ireland, in that Dublin is realizing preemptive mass-traffic-oriented urban development (TOD) considering climate change, the purpose of the study was to classify the methods of research as internal (strong and weak) and external (opportunity and threat) factors through SWOT analysis and to present mass-oriented urban development strategies and policy implications.

EXPRESSION AND FUNCTIONAL CHARACTERIZATION OF ODONTOBLAST-DERIVED GENE: OD314 (상아모세포 관련 유전자, OD314의 발현과 기능 연구)

  • Kim, Doo-Hyun;Kim, Heung-Joong;Jeong, Moon-Jin;Son, Ho-Hyun;Park, Joo-Cheol
    • Restorative Dentistry and Endodontics
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    • v.29 no.4
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    • pp.399-408
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    • 2004
  • Odontoblasts are responsible for the formation and maintenance of dentin. They are known to synthesize unique gene products including dentin sialophosphoprotein (DSPP). Another unique genes of the cells remain unclear. OD314 was isolated from the odontoblasts/pulp cells of rats and partially characterized as an odontoblast-enriched gene (Dey et al., 2001). This study aimed to elucidate the biological function of OD314, relating to odontoblast differentiation and dentinogenesis. After determining the open reading frame (ORP) of OD314 by transient transfection analysis using green fluorescent protein (GPP) expression vector, mRNA in-situ hybridization, immunohistochemistry, reverse transcription-polymerase chain reaction (RT-PCR) and western analysis were performed. The results were as follows: 1. In in-situ hybridization, OD314 mRNAs were expressed in odontoblasts of developing coronal and root pulp. 2. OD314 was a novel protein encoding 154 amino acids, and the protein was mainly expressed in cytoplasm by transient transfection analysis. 3. Mineralized nodules were associated with multilayer cell nodules in the culture of human dental pulp cells and first detected from day 21 using alizarin-red S staining. 4. In RT-PCR analysis, OD314, osteocalcin (OC) and DSPP strongly expressed throughout 28 days of culture. Whereas, osteonectin (ON) mRNA expression stayed low up to day 14, and then gradually decreased from day 21. 5. Western blots showed an approximately 17 kDa band. OD314 protein was expressed from the start of culture and then increased greatly from day 21. In conclusion, OD314 is considered as an odontoblast-enriched gene and may play important roles in odontoblast differentiation and dentin mineralization.

Molecular Dynamics Simulation Studies of Benzene, Toluene, and p-Xylene in NpT Ensemble: Thermodynamic, Structural, and Dynamic Properties

  • Kim, Ja-Hun;Lee, Song-Hi
    • Bulletin of the Korean Chemical Society
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    • v.23 no.3
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    • pp.447-453
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    • 2002
  • In this paper we have presented the results of thermodynamic, structural, and dynamic properties of model systems for liquid benzene, toluene and p-xylene in an isobaric-isothermal (NpT) ensemble at 283.15, 303.15, 323.15, and 343.15 K using molecular dynamics (MD) simulation. This work is initiated to compensate for our previous canonical (NVT) ensemble MD simulations [Bull. Kor. Chem. Soc. 2001, 23, 441] for the same systems in which the calculated pressures were too low. The calculated pressures in the NpT ensemble MD simulations are close to 1 atm and the volume of each system increases with increasing temperature. The first and second peaks in the center of mass g(r) diminish gradually and the minima increase as usual for the three liquids as the temperature increases. The three peaks of the site-site gC-C(r) at 283.15 K support the perpendicular structure of nearest neighbors in liquid benzene. Two self-diffusion coefficients of liquid benzene via the Einstein equation and via the Green-Kubo relation are in excellent agreement with the experimental measures. The self-diffusion coefficients of liquid toluene and p-xylene are in accord with the trend that the self-diffusion coefficient decreases with increasing number of methyl group. The friction constants calculated from the force auto-correlation (FAC) function with the assumption that the fast random force correlation ends at time which the FAC has the first negative value give a correct qualitative trends: decrease with increase of temperature and increase with the number of methyl group. The friction constants calculated from the FAC's are always less than those obtained from the friction-diffusion relation which reflects that the random FAC decays slower than the total FAC as described by Kubo [Rep. Prog. Phys. 1966, 29, 255].

An Effect of Layered Earth on Magnetotelluric Responses of Three-Dimensional Bodies (3차원체의 MT응답에 미치는 층상대지의 효과)

  • Kim, Hee Joon;Hong, Chol Hoon
    • Economic and Environmental Geology
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    • v.27 no.5
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    • pp.491-498
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    • 1994
  • The integral equation method is used for magnetotelluric (MT) modeling of a finite inhomogeneity in a two-layered earth. An integral equation relates the incident plane-wave field and the scattering currents in the three-dimensional (3-D) inhomogeneity through the electric tensor Green's function appropriate to a layered earth. This paper describes an effect of overburden and basement on MT responses of 3-D body. The effect of overburden is to reduce the detectability of target, and the reduction of detectability is more apparent for conductive overburden than for resistive one. The effect of basement, on the other hand, may enhance the anomaly due to 3-D body in the upper layer. In case of the resistive basement current perturbations about the body tend to be confined to the more conductive upper layer.

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Electron Trapping and Transport in Poly(tetraphenyl)silole Siloxane of Quantum Well Structure

  • Choi, Jin-Kyu;Jang, Seung-Hyun;Kim, Ki-Jeong;Sohn, Hong-Lae;Jeong, Hyun-Dam
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.02a
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    • pp.158-158
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    • 2012
  • A new kind of organic-inorganic hybrid polymer, poly(tetraphenyl)silole siloxane (PSS), was invented and synthesized for realization of its unique charge trap properties. The organic portions consisting of (tetraphenyl)silole rings are responsible for electron trapping owing to their low-lying LUMO, while the Si-O-Si inorganic linkages of high HOMO-LUMO gap provide the intrachain energy barrier for controlling electron transport. Such an alternation of the organic and inorganic moieties in a polymer may give an interesting quantum well electronic structure in a molecule. The PSS thin film was fabricated by spin-coating of the PSS solution in THF organic solvent onto Si-wafer substrates and curing. The electron trapping of the PSS thin films was confirmed by the capacitance-voltage (C-V) measurements performed within the metal-insulator-semiconductor (MIS) device structure. And the quantum well electronic structure of the PSS thin film, which was thought to be the origin of the electron trapping, was investigated by a combination of theoretical and experimental methods: density functional theory (DFT) calculations in Gaussian03 package and spectroscopic techniques such as near edge X-ray absorption fine structure spectroscopy (NEXAFS) and photoemission spectroscopy (PES). The electron trapping properties of the PSS thin film of quantum well structure are closely related to intra- and inter-polymer chain electron transports. Among them, the intra-chain electron transport was theoretically studied using the Atomistix Toolkit (ATK) software based on the non-equilibrium Green's function (NEGF) method in conjunction with the DFT.

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Analysis of Large-Amplitude Ship Motions Using a Cartesian-Gridbased Computational Method (직교격자 기반 수치기법을 이용한 선박의 대변위 운동해석)

  • Yang, Kyung-Kyu;Nam, Bo-Woo;Lee, Jae-Hoon;Kim, Yonghwan
    • Journal of the Society of Naval Architects of Korea
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    • v.49 no.6
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    • pp.461-468
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    • 2012
  • In this study, a Cartesian-grid method based on finite volume approach is applied to simulate the ship motions in large amplitude waves. Fractional step method is applied for pressure-velocity coupling and TVD limiter is used to interpolate the cell face value for the discretization of convective term. Water, air, and solid phases are identified by using the concept of volume-fraction function for each phase. In order to capture the interface between air and water, the tangent of hyperbola for interface capturing (THINC) scheme is used with weighed line interface calculation (WLIC) method which considers multidimensional information. The volume fraction of solid body embedded in the Cartesian grid system is calculated using a level-set based algorithm, and the body boundary condition is imposed by a volume weighted formula. Numerical simulations for the two-dimensional barge type model and Wigley hull in linear waves have been carried out to validate the newly developed code. To demonstrate the applicability for highly nonlinear wave-body interactions such as green water on the deck, numerical analysis on the large-amplitude motion of S175 containership is conducted and all computational results are compared with experimental data.

A study for Earthquake Parameter of Uljin Earthquake (울진지진(2004/05/29)의 지진원 특성에 관한 연구)

  • Kim, Jun-Kyoung
    • Journal of the Earthquake Engineering Society of Korea
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    • v.11 no.6
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    • pp.33-39
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    • 2007
  • The seismic source parameters of the Uljin earthquake on 29 May 2004, including focal depth, focal mechanism, magnitude, and moment tensor elements for source characteristics, are analysed using moment tensor seismic source inversion. The Green‘s function for 3 crust models representing the southern Korean Peninsula are used. Also 3 kinds of epicenters are used to find optimum solution for seismic source parameters. Results show that seismic source parameters have a little dependency of azimuthal distribution and epicentral distances of seismic stations. Final results show that the event, considering 6 moment tensor elements, is caused by the typical reverse fault with nearly NS strike. The focal mechanism implies that the tectonic force around epicenter area currently has compressive environment, with nearly EW principal axis. The focal depth is estimated to be about 12km. The resultant focal mechanism show fairly good agreement to those of other studies. However, focal depth is much different from that of other studies.

A WUSCHEL Homeobox Transcription Factor, OsWOX13, Enhances Drought Tolerance and Triggers Early Flowering in Rice

  • Minh-Thu, Pham-Thi;Kim, Joung Sug;Chae, Songhwa;Jun, Kyong Mi;Lee, Gang-Seob;Kim, Dong-Eun;Cheong, Jong-Joo;Song, Sang Ik;Nahm, Baek Hie;Kim, Yeon-Ki
    • Molecules and Cells
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    • v.41 no.8
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    • pp.781-798
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    • 2018
  • Plants have evolved strategies to cope with drought stress by maximizing physiological capacity and adjusting developmental processes such as flowering time. The WOX13 orthologous group is the most conserved among the clade of WOX homeodomain-containing proteins and is found to function in both drought stress and flower development. In this study, we isolated and characterized OsWOX13 from rice. OsWOX13 was regulated spatially in vegetative organs but temporally in flowers and seeds. Overexpression of OsWOX13 (OsWOX13-ov) in rice under the rab21 promoter resulted in drought resistance and early flowering by 7-10 days. Screening of gene expression profiles in mature leaf and panicles of OsWOX13-ov showed a broad spectrum of effects on biological processes, such as abiotic and biotic stresses, exerting a cross-talk between responses. Protein binding microarray and electrophoretic mobility shift assay analyses supported ATTGATTG as the putative cis-element binding of OsWOX13. OsDREB1A and OsDREB1F, drought stress response transcription factors, contain ATTGATTG motif(s) in their promoters and are preferentially expressed in OsWOX13-ov. In addition, Heading date 3a and OsMADS14, regulators in the flowering pathway and development, were enhanced in OsWOX13-ov. These results suggest that OsWOX13 mediates the stress response and early flowering and, thus, may be a regulator of genes involved in drought escape.

Public Administration Town Plan of Sejong-City based on Landscape Ecological Perspectives (경관생태학적 관점에서의 세종시 중심행정타운 조성계획)

  • Lee, Ai-Ran
    • Ecology and Resilient Infrastructure
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    • v.1 no.2
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    • pp.94-101
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    • 2014
  • This is the urban design master plan for the Public Administration Town. The project proposes a newly configured city, where environmental and democratic principles are expressed in the shape of the urban fabric. To achieve the goal, the concepts of 'Flat City, Link City, and Zero City' were introduced. These concept show "Space fabric arrange, connection and material circulation and flow from ecological landscape". 'Flat City' shaped the government buildings into an iconic plane, and democratic society. The iconic plane's surface extends across the whole city, creating an expansive public park, which is easily accessible, and open to nature. 'Link City' connects governmental agencies to enhance their function and interactions. Government facilities, parks and green spaces, cultural facilities, commercial zones, and residential districts areas create an interconnecting network. 'Zero City' has integrated infrastructure systems to reuse waste, reduce pollution, and provide essential city functions. It creates a new wildlife habitat, making 'Zero City' a good neighborhood. This proposal was made to integrate historical, regional, nature experiences with various approaches in architecture, city, and landscape architecture.