• Transactions of Materials Processing
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• v.8 no.3
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• pp.319-319
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• 1999

From isothermal and cyclic oxidation tests on thermomechanically treated Ti-5%Al, Ti47%Al-4%Cr, and Ti-48%Al-2%Cr-2%Nb alloys at 800, 900, 1000℃ in air, it was found that Ti-48%Al-2%Cr-2%Nb and Ti-47%Al-4%Cr had the best and the worst oxidation resistance, respectively. The oxide scales consisted primarily of TiO₂and Al₂O₃, with and without a small amount of dissolved Cr and 7b ions, depending on the alloy composition. These ions were slightly enriched inside the inner oxide layer, and strongly enriched around the scale-matrix interface. The outer TiO₂-rich layer was formed by the outward diffusion of Ti ions, while the inner (TiO₂+A1₂O₃,) mixed layer was formed by the inward transport of oxygen. The outward movement of Al ions farmed the intermediate Al₂O₃-rich Iayer, above talc prepared alloys.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.12 no.1
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• pp.88-93
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• 1999

This paper describes the electron transport characteristics in $SiH_4$ gas calculated for the range of E/n:0.5~300(Td) and Pressure:0.5, 1, 2.5(Torr) by the Monte carlo simulation and Boltzmann equation method using a set of electron collision cross sections determined by the reported results. The motion has been calculated to give swarm parameters for the electron drift velocity, longitudinal and transverse diffusion coefficients, the electron ionization coefficients, characteristics energy and the electron energy distribution function. The electron energy distributions function has been analysed in $SiH_4$ at E/N: 30, 50(Td)for a case of the equilibrium region in the mean electron energy and respective set of electron collision cross sections. The results of Monte carlo simulation and Boltzmann equation have been compared with experimental data by ohmori ad Pollock.

• Steel and Composite Structures
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• v.38 no.5
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• pp.523-531
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• 2021

The generalized thermoelastic analysis problem of a two-dimension porous medium with and without energy dissipation are obtained in the context of Green-Naghdi's (GNIII) model. The exact solutions are presented to obtain the studying fields due to the pulse heat flux that decay exponentially in the surface of porous media. By using Laplace and Fourier transform with the eigenvalues scheme, the physical quantities are analytically presented. The surface is shocked by thermal (pulse heat flux problems) and applying the traction free on its outer surfaces (mechanical boundary) through transport (diffusion) process of temperature to observe the analytical complete expression of the main physical fields. The change in volume fraction field, the variations of the displacement components, temperature and the components of stress are graphically presented. Suitable discussion and conclusions are presented.

• International Commerce and Information Review
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• v.4 no.2
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• pp.279-301
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• 2002

Lately, one of the most representative phases on business world is the diffusion of internet business. This change has been making new port business model called 'e-Port' in maritime transport. The focus of this article is to suggest some strategies on the implementation of e-Port in Korea. To research and analyze the e-Port realities, we first reviewed the previous study on Internet Marketing and e-Business. Six strategies that are critical on e-Port model were classified: (1) contents, (2) community, (3) commerce, (4) connection, (5) communication, (6) customization. Secondly, we chose and evaluated website of eight ports: Hongkong, Singapore, Antwerp, Hamburg, as successful e-port models. And then, we investigated actual conditions of e-Port in Pusan, Inchon, K wangwang, and Gusan. And then we try to find effective plan on the operation of e-Port.

• Journal of Fisheries and Marine Sciences Education
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• v.13 no.2
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• pp.132-145
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• 2001

The cold discharge from LNG(liquefied natural gas) terminal makes the water temperature around the terminal fall down. This temperature reduction may result in serious changes on marine ecosystem of the coastal area. The numerical model experiments of material transport and tidal circulation in the inner bay, Chinhae Bay are investigated in the dispersion of cold discharge from LNG terminal. The condition of ambient water is exposed to tide, tidal current and cold discharge temperature. Simple numerical model experiments highlight the importance of tidal circulation and cold discharge at each case and some results are discussed. The results of this study can be used as the guideline for the site selection of LNG terminals and long-term marine environmental impact assessment.

• Journal of Sensor Science and Technology
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• v.27 no.4
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• pp.264-268
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• 2018

Vertically-aligned $TiO_2$ nanotube electrodes have attracted considerable attention for applications in solar cells, catalysts, and sensors, because of their ideal structure for electron transport and electrolyte diffusion. Here, we prepare vertically-aligned $TiO_2$ nanotube electrodes using a two-step anodization process. The prepared $TiO_2$ nanotube electrodes exhibit uniform pore structures with an inner diameter of ~80-90 nm and wall thickness of ~20-25 nm. In addition, they exhibit an anatase crystal phase after a high-temperature annealing. The annealed $TiO_2$ nanotube electrodes are applied in dye-sensitized solar cells (DSSCs) as photoanodes. The fabricated DSSC exhibits conversion efficiencies of 3.46 and 2.15% with liquid- and gel-type electrolytes, respectively.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.1
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• pp.19-23
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• 2014

This paper describes the electron transport characteristics in $SF_6$-He gas calculated E/N values 0.1~700[Td] by the Monte Carlo simulation and Boltzmann equation method using a set of electron collision cross sections determined by the authors and the values of electron swarm parameters obtained by TOF method. This study gained the values of the electron swarm parameters such as the electron drift velocity, the electron ionization or attachment coefficients, longitudinal and transverse diffusion coefficients for $SF_6$-He gas at a range of E/N. A set of electron collision cross section has been assembled and used in Monte Carlo simulation to predict values of swarm parameters. The result of Boltzmann equation and Monte Carlo Simulation has been compared with experimental data by Ohmori, Lucas and Carter. The swarm parameter from the swarm study are expected to sever as a critical test of current theories of low energy scattering by atoms and molecules.

• Journal of the Korean institute of surface engineering
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• v.35 no.4
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• pp.193-198
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• 2002

Alloys of XD45 (Ti45A12Nb2Mn-0.8vol%TiB$_2$) and XD47 (Ti47A12Nb2Mn-0.8vol%TiB$_2$) were oxidized between 800 and $1000^{\circ}C$ in air, and their oxidation characteristics were studied. The oxide scales consisted primarily of an outer $TiO_2$ layer, an intermediate $Al_2$$O_3$-rich layer, and an inner mixed layer of ($TiO_2$+$Al_2$$O_3$). Nb tended to present at the lower part of the oxide scale, whereas Mn at the upper part of the oxide scale. The Pt marker tests indicated that the outer oxide layer grew primarily by the outward diffusion of Ti and Mn, and the inner mixed layer by the inward transport of oxygen.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.199-202
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• 2008

It is well-known fact that tidal difference between the ebb and flow in Yellow Sea is about 9 m so that it has largest value in the world. This wide range of tide level enables Yellow Sea water to intrude into main stream of Han River. However, the study of the tidal reach of Han River has not been carried out thoroughly since North and South Koreas share this region so that topography data and physical measurement are lacking. In this study, to examine the reverse flow and dispersion behavior by tidal effect at the tidal reach of Han River, 2-D river analysis models were applied. RMA-2 was applied to calculate the horizontal velocities and water surface elevation. With the results of velocities and water depth, RAM4, which is 2-D advection-dispersion model based on FEM was simulated to analyze the horizontal transport behavior of BOD.

• Korean Chemical Engineering Research
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• v.57 no.3
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• pp.368-371
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• 2019

Using first principles calculations we investigated the thermomechanical stability of spent nuclear fuels (SNF), especially how mechanical properties of $UO_2$, such as, bulk, shear and Young's moduli and Poisson's ratio vary through alpha-decay of U into Th with generation of He gas. Our results indicate that substitution of U by Th through alpha decay ($U_{1-x}Th_xO_2$) does not significantly affect the stability of the grain in a fuel matrix. In addition, we studied the transport properties of He in and boundaries of the $U_{1-x}Th_xO_2$ grain. Helium preferentially resides at the grain boundaries through diffusion. Our study can contribute to substantial reduction of environmentally risk and enhancement of our sustainability by safe control of radioactive materials.