• Ocean and Polar Research
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• v.28 no.2
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• pp.175-186
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• 2006

There are disputes for oil and gas development between China and Japan in the East China Sea. These involve the area where China is already carrying out activities of oil and gas development and where Japan is proclaiming its EEZ. China insists that the Chinese activities on oil and gas development area are being carried out within the Chinese jurisdictional waters even if the median line principle of Japanese proclamation is applied in delimitation. Indeed, the permit for Japanese development is causing disputes between China and Japan because its permit allows development in the waters adjacent to Chinese development area. h the event, the core of this dispute around the oil and gas field in the East China Sea relates to issues of maritime boundary delimitation and issues of resources acquisition with both states. Chinese policy on oil and gas development is to first consider development issues in accordance with a median line principle where waters toward to China from the median line should be developed by China and the area toward Japan from the median line within the Chinese continental shelf should be jointly developed. However, the Japanese position is that the East China Sea should be jointly developed, and Japan hopes to eventually convince China to accept its median line delimitation. With on-going development of such issues, Korea should establish a strategy of negotiation based on analyses of resource distributional conditions and other strategic factors in the Korean delimitation area. In particular, Korea should prepare and make the best use of joint development zone established in an agreement between the ROK and Japan concerning the development of the southern part of continental shelf adjacent to both states.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.12
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• pp.1715-1721
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• 2002

Numerical analysis was conducted to characterize the gas flow field and particle deposition on a horizontal freestanding semiconductor wafer under the laminar flow field at vacuum environment. In order to calculate the properties of gas, the gas was assumed to obey the ideal gas law. The particle transport mechanisms considered were convection, Brownian diffusion and gravitational settling. The averaged particle deposition velocities and their radial distributions fnr the upper surface of the wafer were calculated from the particle concentration equation in an Eulerian frame of reference for system pressures of 1 mbar~1 atm and particle sizes of 2nm~10$^4$ nm(10 ${\mu}{\textrm}{m}$). It was observed that as the system pressure decreases, the boundary layer of gas flow becomes thicker and the deposition velocities are increased over the whole range of particle size. One thing to be noted here is that the deposition velocities are increased in the diffusion dominant particle size range with decreasing system pressure, whereas the thickness of the boundary layer is larger. This contradiction is attributed to the increase of particle mechanical mobility and the consequent increase of Brownian diffusion with decreasing the system pressure. The present numerical results showed good agreement with the results of the approximate model and the available experimental data.

• Membrane and Water Treatment
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• v.11 no.5
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• pp.353-361
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• 2020

The present study deals with a numerical investigation of heat and mass transfer in a Sweeping Gas Membrane Distillation (SGMD) used for desalination. The governing equations expressing the conservation of mass, momentum, energy and species with coupled boundary conditions were solved numerically. The slip boundary condition applied on the feed saline solution-hydrophobic membrane interface is taken into consideration showing its effects on profiles and process parameters.The numerical model was validated with available experimental data and was found to be in good agreement particularly when the slip condition is considered. The results of the simulations highlighted the effect of slip boundary condition on the velocity and temperature distributions as well as the process effectiveness. They showed in particular that as the slip length increases, the permeate flux of fresh water and process thermal efficiency rise.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1688-1691
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• 2007

This paper shows that the boundary image sticking can be prohibited completely by using the vacuum sealing process, which means that the residual impurities such as nitrogen or oxygen can be a critical factor inducing the boundary image sticking. The production of boundary image sticking was checked in the test panel fabricated by the $N_2$ or $O_2$ flow during the vacuum sealing process. As a result, the boundary image sticking did not appear in the case of $N_2flow$, whereas the boundary image sticking was observed in the case of $O_2$ flow even though the test panel was fabricated by the vacuum sealing process.

• 유체기계공업학회:학술대회논문집
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• 2001.11a
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• pp.287-292
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• 2001

The objective of this study is to verify the secondary flow and the total pressure loss distribution in the boundary layer fence installed linear turbine cascade passage and to propose an appropriate height of the boundary layer fence which shows the best loss reduction among the simulated fences. In this study three different boundary layer fence was installed which have different height. This study was performed by numerical method and the result showed the boundary layer fence which has the height of one third of the inlet boundary layer thickness showed the best loss reduction rate.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.7
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• pp.693-700
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• 2008

High-Pressure gas Pipeline which is buried in underground has the Possibility that will be exposed to unexpected dangerous impact of construction equipment. To protect from this kind of danger, the real-time health monitoring system of the high-pressure gas pipeline is necessary. First of all, to make the real-time health monitoring system clearly, the acoustic wave propagation characteristics which are made from various construction equipment impacts must be identified. In link of technical development that prevents the damage of high-pressure gas pipeline, this paper gives FEM(finite element method) and BEM(boundary element method) solutions to identify the acoustic wave propagation characteristic of the various impact input signals which consist of Direc delta function and convolution signal of 45 Hz square signal and random signal.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.11
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• pp.1060-1071
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• 2005

Passive gas dispersions over a 1/1000 scale terrain model at Eiffel type wind tunnel were reproduced by numerical simulation. Large eddy simulation was used to treat the sub-grid scale turbulences. The terrain features were represented by millions of point forces densely distributed over the solid surface using the virtual boundary method. The model simulations agreed very well with the experiments in a consistent fashion for all wind directions. The measured profiles of the wind speeds as well as the tracer gas concentrations were nicely simulated by the CFD model at most locations scattered over the model terrain. With scale factor adjusted and the thermal stratification effects incorporated, the CFD model was expected to provide reliable information on pollutant dispersions over the real complex terrains.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.103-108
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• 2003

In this paper, the current lead for superconducting device is studied by numerical method. The current lead is cooled by surrounded $N_{2}$ gas by natural convection. The heat conduction equation for current lead and boundary layer equation for $N_{2}$ gas must be solved simultaneously. The boundary layer equation for $N_{2}$ gas is highly nonlinear for varied temperature of current lead. So the linearization method is adopted for simplicity. Numerical results using natural convection cooling are compared with the conventional cooling methods such as conduction cooling and vapor cooling methods. The main difference of natural convection cooing is the non-zero temperature gradient at the top of current lead for the minimum heat dissipation into superconducting devices. For the optimized conduction-cooling and vapor-cooling current leads, the temperature gradient at the top of current lead is zero. Also, the heat flow at the cold end is much smaller than conduction cooling case.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.252-255
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• 1996

Cl-based gas chemistry is generally used to etching for Al alloy metallization. After the etching of Al alloy with Cl-based gas plasma, residual chlorine on Al alloy reacts with $H_2O$ due to air exposure and results in Al corrosion. In this study, the corrosion Phenomena of Al were examined with XPS(X-ray photoelectron spectroscopy) and SEF(Scanning electron microscopy). It was confirmed that chlorine mainly existed at the grain boundary of Al alloy after plasma etching of Al alloy with Cl-based gas chemistry and Al corrosion was largely generated at the grain boundary of Al a1loy. And residual chlorine was passivated by sulfur and fluorine which were generated by SF$_{6}$ plasma. These effects of passivation reduced the Al corrosion due to air exposure.e.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.10
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• pp.2418-2425
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• 1993

A two-dimensional transient heat transfer model for reactive gas assisted laser cutting process with a moving Gaussian heat source is developed using a numerical finite difference technique. The kerf width, melting front shape and temperature distribution were calculated by using the boundary-fitted coordinate system to handle the ejection of workpiece material and heat input from reaction and evaporation. An analytical solution for cutting front movement was adopted and numerical simulation was performed to calculate the temperature distribution and melting front thickness. To calculate the moving velocity of cutting front, the normal distribution of the cutting gas velocity was used. The kerf width was revealed to be dependent on the cutting velocity, laser power and cutting gas velocity.