• KIEE International Transactions on Electrophysics and Applications
• /
• 제4C권5호
• /
• pp.220-229
• /
• 2004

We have examined a technique of one-dimensional (1D) fluid modeling for radio-frequency Ar capacitively coupled plasmas (CCP) between unequal-sized powered and grounded electrodes. In order to simulate a practical CCP reactor configuration with a grounded side wall by the 1D model, it has been assumed that the discharge space has a conic frustum shape; the grounded electrode is larger than the powered one and the discharge space expands with the distance from the powered electrode. In this paper, we focus on how much a 1D model can approximate a 2D model and evaluate their comparisons. The plasma density calculated by the 1D model has been compared with that by a two-dimensional (2D) fluid model, and a qualitative agreement between them has been obtained. In addition, 1D and 2D calculation results for another reactor configuration with equal-sized electrodes have also been presented together for comparison. In the discussion, four CCP models, which are 1D and 2D models with symmetric and asymmetric geometries, are compared with each other and the DC self-bias voltage has been focused on as a characteristic property that reflects the unequal electrode surface areas. Reactor configuration and experimental parameters, which the self-bias depends on, have been investigated to develop the ID modeling for reactor geometry with unequal-sized electrodes.

• 동의생리병리학회지
• /
• 제27권5호
• /
• pp.563-569
• /
• 2013

This study was undertaken to apply the yin-yang theory in action potential. In order to apply the yin-yang theory in action potential, nature of yin and yang, interrelation of yin and yang and action potential in cell were reviewed. According to the yin-yang theory, inner cellular space corresponds to yin, but outer cellular space corresponds to yang. If we classify ions in intracellular fluid or extracellular fluid by nature of yin and yang, potassium(K+) corresponds to yang within yin(陰中之陽), protein(Pr-) corresponds to yin within yin(陰中之陰) in intracellular fluid, and sodium(Na+) corresponds to yang within yang(陽中之陽), chloride(Cl-) corresponds to yin within yang(陽中之陰) in extracellular fluid. Double donnan equilibrium and equilibrium potential were caused by intracellular anion(Pr-) and extracellular cation(Na+) are related with mutual rooting of yin and yang(陰陽互根) and opposition of yin and yang(陰陽對立). The influx and efflux of ion through cell membrane means waxing and waning of yin and yang(陰陽消長), the change of membrane potential means yin-yang conversion(陰陽轉化) during action potential.

• 한국가시화정보학회지
• /
• 제15권1호
• /
• pp.32-40
• /
• 2017

Interaction between fluid and a rigid object is frequently observed in everyday life. However, it is difficult to simulate their interaction as the medium and the object have different representations. One of the challenging issues arises especially in handling deformation of the object visually as well as rendering haptic feedback. In this paper, we propose a real-time simulation technique for multimodal interaction between particle-based fluids and soluble solids. We have developed the dissolution behavior model of solids, which is discretized based on the idea of smoothed particle hydrodynamics, and the changes in physical properties accompanying dissolution is immediately reflected to the object. The user is allowed to intervene in the simulation environment anytime by manipulating the solid object, where both visual and haptic feedback are delivered to the user on the fly. For immersive visualization, we also adopt the screen space fluid rendering technique which can balance realism and performance.

• 천문학회지
• /
• 제37권1호
• /
• pp.55-59
• /
• 2004

We have developed a two fluid solar wind model from the Sun to 1 AU. Its basic equations are mass, momentum and energy conservations. In these equations, we include a wave mechanism of heating the corona and accelerating the wind. The two fluid model takes into account the power spectrum of Alfvenic wave fluctuation. Model computations have been made to fit observational constraints such as electron($T_e$) and proton($T_p$) temperatures and solar wind speed(V) at 1 AU. As a result, we obtained physical quantities of solar wind as follows: $T_e$ is $7.4{\times}10^5$ K and density(n) is $1.7 {\times}10^7\;cm^{-3}$ in the corona. At 1 AU $T_e$ is $2.1 {\times} 10^5$ K and n is $0.3 cm^{-3}$, and V is $511 km\;s^{-1}$. Our model well explains the heating of protons in the corona and the acceleration of the solar wind.

• Geomechanics and Engineering
• /
• 제15권1호
• /
• pp.645-657
• /
• 2018

The paper aims to analyze the behaviour of torsional type surface waves propagating through fluid saturated inhomogeneous porous media clamped between two inhomogeneous anisotropic media. We considered three types of inhomogeneities in upper anisotropic layer which varies exponentially, quadratically and hyperbolically with depth. The anisotropic half space inhomogeneity varies linearly with depth and intermediate layer is taken as inhomogeneous fluid saturated porous media with sinusoidal variation. Following Biot, the dispersion equation has been derived in a closed form which contains Whittaker's function and its derivative, for approximate result that have been expanded asymptotically up to second term. Possible particular cases have been established which are in perfect agreement with standard results and observe that when one of the upper layer vanishes and other layer is homogeneous isotropic over a homogeneous half space, the velocity of torsional type surface waves coincides with that of classical Love type wave. Comparative study has been made to identify the effects of various dimensionless parameters viz. inhomogeneity parameters, anisotropy parameters, porosity parameter, and initial stress parameters on the torsional wave propagation by means of graphs using MATLAB. The study has its own relevance in connection with the propagation of seismic waves in the earth where fluid saturated poroelastic layer is present.

• 한국항공우주학회지
• /
• 제37권6호
• /
• pp.571-579
• /
• 2009

에너지 물질과 같이 연소 반응을 하는 압축성 물질을 해석하기 위하여 Hydro-SCCM (Shock Compression of Condensed Matter)이라는 에너지 물질과 비반응 물질을 포함한다중 물질 해석툴을 개발하였다. 고에너지 물질은 강한 충격파와 고온과 고압을 가진 물질경계면에서 높은 변형률을 발생시킨다. 이러한 큰 구배를 가진 현상을 해석하기 위하여 새로운 오일러리안 기법을 사용하였다. 본 논문에서는 현상을 해석하기 위한 수학적 방법과 해석결과를 소개하였다.

• 한국마린엔지니어링학회:학술대회논문집
• /
• 한국마린엔지니어링학회 2006년도 전기학술대회논문집
• /
• pp.61-62
• /
• 2006

The suppression of fluid force acting on a square prism near plane wall was studied by attaching fences on the comers of the prism. The height of the fence was 10% of the square width and the range of Reynolds number considered was $Re=2.0{\times}10^4$. The experimental parameters were the attaching position and numbers of fences, the space ratios $G/B(G/B=0.1{\sim}1.2)$ between prism and plane wall. The average drag coefficients were increased and the average hit coefficients were decreased and increased with the space ratios foulard plane wall. The drag of the prism was reduced average 7.6% with the space ratios by attaching the normal fence at the rear and upper comer and the horizontal normal fence at the rear and lower corner on the prism.

• International Journal of Aeronautical and Space Sciences
• /
• 제7권1호
• /
• pp.1-12
• /
• 2006

In this study, a surrogate model is applied to multi-objective aerodynamic optimization design. For the balanced exploration and exploitation, each objective function is converted into the Expected Improvement (EI) and this value is used as fitness value in the multi-objective optimization instead of the objective function itself. Among the non-dominated solutions about EIs, additional sample points for the update of the Kriging model are selected. The present method was applied to a transonic airfoil design. Design results showed the validity of the present method. In order to obtain the information about design space, two data mining techniques are applied to design results: Analysis of Variance (ANOVA) and the Self-Organizing Map (SOM).

• 한국유체기계학회 논문집
• /
• 제13권1호
• /
• pp.35-41
• /
• 2010

Experimental study on the flow field inside the nozzle for radial turbine was performed. At design point, the pressure is high and the Mach number is low at the pressure side of the nozzle inlet semi-vaneless space as the flow turns through the nozzle vanes. As the flow accelerates through the nozzle passage to the throat the pressure level at the pressure and suction sides becomes similar. The flow continued accelerating from the throat to the inlet of turbine wheel and the pressure field became uniform in the circumferential direction in the vaneless space. In high expansion ratio condition, strong favorable pressure gradient band region occurred just after the throat in the semi-vaneless space in the circumferential direction and the pressure became uniform in the circumferential direction after this band. In low expansion ratio condition, core flow acceleration is dominant after the throat and this non-uniform pressure field reached to the inlet of turbine wheel.

• Imaging Science in Dentistry
• /
• 제43권1호
• /
• pp.55-58
• /
• 2013

A ranula is a bluish, transparent, and thin-walled swelling in the floor of the mouth. They originate from the extravasation and subsequent accumulation of saliva from the sublingual gland. Ranulas are usually limited to the sublingual space but they sometimes extend to the submandibular space and parapharyngeal space, which is defined as a plunging ranula. A 21-year-old woman presented with a complaint of a large swelling in the left submandibular region. On contrast-enhanced CT images, it dissected across the midline, and extended to the parapharyngeal space posteriorly and to the submandibular space inferiorly. Several septa and a fluid-fluid level within the lesion were also demonstrated. We diagnosed this lesion as a ranula rather than cystic hygroma due to the location of its center and its sublingual tail sign. As plunging ranula and cystic hygroma are managed with different surgical approaches, it is important to differentiate them radiologically.