• Membrane Journal
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• v.10 no.3
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• pp.139-147
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• 2000

Non-Fickian (or anomalous) diffusion was observed in transient sorption of aromatic solvents(such as benzene, toluene, and chlorobenzene) in fluoropolymers (such as ETFE, ECTFE and PVDF). In this study, five other transient sorption models (Crank, Long ＆ Richman, Berens ＆ Hopfenberg, Neogi, Li) based on Fick's law were employed to fit the anomalous sorption data for aromatic solvents. The adjustable parameters were determined by least square analysis of the measured and predicted fractional uptake. For ETFE sorption data slightly deviating from Fickian behavior, all the models exhibited satisfactory results in fitting the anomalous sorption data. In particular, Neogj model predicted intrinsic diffusivity (0.4～0.8$\times$10$^{-5}$ $\textrm{cm}^2$/day) and equilibrium diffusivity (0.13～0.31$\times$10$^{-4}$ $\textrm{cm}^2$/day) as well as relaxation kinetics related to non-Fickain diffusion. For a typical sigmoidal sorption behavior in PVDF, only Crank's model could give the reasonable evaluation on transport properties. The ratio of intial diffusivity (D$_{i}$) to final equilibrium diffusivity (D$_{\infty}$) was ranged from 80 to 200. For the final stage of uptake In ECTFE with drastic acceleration, all the models exhibited significant deviations from the sorption data. New diffusion models based on thermodynamics and continuum mechanics should be employed to get valuable information on transport properties as well as relaxation kinetics coupled with non-Fickian diffusion.

• Journal of The Korean Astronomical Society
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• v.36 no.spc1
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• pp.55-61
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• 2003

There are at least three effects of the non-thermal particle bombardment on the solar atmosphere: (1) non-thermal ionization and excitation; (2) proton-hydrogen charge exchange; (3) impact line polarization. Due to the non-thermal ionization and excitation effects of electron bombardments in flares, H$\alpha$ line is widely broadened and shows a strong central reversal. Significant enhancements at the line wings of Ly$\alpha$ and Ly$\beta$ are also predicted. In the case of proton bombardment, less strong broadening and no large central reversal are expected. However, due to proton-hydrogen charge exchange, the enhancements at the red wings of Ly$\alpha$ and especially of Ly$\beta$ lines at the early impulsive phase of flares are significant. Electron beam can also in some cases generates visible and UV continuum emission in white-light flares. However, at the onset phase, a negative 'black' flare may appear in several seconds, due to the increase of the $H^-$ opacity. The impact polarization of atomic lines can provide complementary information on the energetic particles, the energy transport and deposit in the solar chromosphere. New results of spectropolarimetric analysis for the major flare on July 23, 2002 are also given in the paper.

• Journal of the Korean Home Economics Association
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• v.46 no.7
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• pp.35-45
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• 2008

For the highly involved and emotional product, such as cosmetic product, the consumer focuses on the information about the symbolic meaning of a product. As a continuum, cosmetic advertising frequently requires a celebrity and/or cue since it provides identification between customer and cosmetic. Although many studies have examined the effectiveness of the congruence between brand image and self-image, there are little research regarding the congruence between advertising image and self image. The objective of this study is to examine the attitudinal effectiveness of the congruence between cosmetic advertising image and self-image. For the experiment, 2(ad type: rational vs emotional) factorial designs were performed. A total of 240 undergraduate female students participated in the experiment. The results of the study are as follows. First, the congruence had a significantly positive influence on advertising attitude, but not on brand attitude. Second, the type of cosmetic advertising caused differences in attitudinal persuasiveness affected by the congruence.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.481-484
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• 2005

The AutoForm previously used the membrane element and it accomplished sheet metal forming analysis. The membrane analysis has been widely applied to various sheet metal forming processes because of its time effectiveness. However, it's well known that the membrane analysis can not provide correct information for the processes which have considerable bending effects. In this research it tried to compare the analysis results which use the shell element which is applied newly in the AutoForm commercial software with actual experimental results. The shell element is compromise element between continuum element and membrane element. The Finite element method by using shell element is the most efficient numerical method. From this research, it is known that FEA by using shell element can predict accurately the problems happened in actual experimental auto-body panel.

• Proceedings of the KIEE Conference
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• 2007.11c
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• pp.183-186
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• 2007

Realistic deformation of computer simulated anatomical structures is computationally intensive. As a result, simple methodologies not based in continuum mechanics have been employed for achieving real time deformation of virtual reality. Since the graphical interpolations and simple spring models commonly used in these simulations are not based on the biomechanical properties of tissue structures, these "quick and dirty"methods typically do not accurately represent the complex deformations and force-feedback interactions that can take place during surgery. Finite Element(FE) analysis is widely regarded as the most appropriate alternative to these methods. However, because of the highly computational nature of the FE method, its direct application to real time force feedback and visualization of tissue deformation has not been practical for most simulations. If the mathematics are optimized through pre-processing to yield only the information essential to the simulation task run-time computation requirements can be drastically reduced. To apply the FEM, We examined a various in verse matrix method and a deformed material model is produced and then the graphic deformation with this model is able to force. As our simulation program is reduced by the real-time calculation and simplification because the purpose of this system is to transact in the real time.

• Journal of Communications and Networks
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• v.10 no.2
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• pp.213-220
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• 2008

This paper analyzes a broadcasting technique for wireless multi-hop sensor networks that uses a form of cooperative diversity called opportunistic large arrays (OLAs). We propose a method for autonomous scheduling of the nodes, which limits the nodes that relay and saves as much as 32% of the transmit energy compared to other broadcast approaches, without requiring global positioning system (GPS), individual node addressing, or inter-node interaction. This energy-saving is a result of cross-layer interaction, in the sense that the medium access control (MAC) and routing functions are partially executed in the physical (PHY) layer. Our proposed method is called OLA with a transmission threshold (OLA-T), where a node compares its received power to a threshold to decide if it should forward. We also investigate OLA with variable threshold (OLA-VT), which optimizes the thresholds as a function of level. OLA-T and OLA-VT are compared with OLA broadcasting without a transmission threshold, each in their minimum energy configuration, using an analytical method under the orthogonal and continuum assumptions. The trade-off between the number of OLA levels (or hops) required to achieve successful network broadcast and transmission energy saved is investigated. The results based on the analytical assumptions are confirmed with Monte Carlo simulations.

• Journal of The Korean Astronomical Society
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• v.29 no.spc1
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• pp.169-170
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• 1996

In the past, it. was very difficult to distinguish thermal and non-thermal emission. Broadbent et a1. (1989) has developed a new technique with the help of the IRAS 60 micron emission. The distribution of non-thermal or synchrotron emission in the Galactic disk has been modeled from the 408 MHz all sky survey of Haslam et a1. (1982) after removal of the thermal component.. At. 408 MHz, t.here is very little absorption in the interstellar medium and the distribution along the line-of-sight. is inferred mainly from its presumed relationship to other tracers of spiral structure via a. number of fitted parameters. But. at lower frequencies, free-free absorption becomes important and can give some direct. information on the line of sight. distribution. We have modeled the thermal electron density according to the spiral arm models and the distribution of ionized hydrogen in the Galactic plane by Lockman (1976) and Cersosimo et. al. (1989) and have made predictions to compare with the surveys of Dwarakanath et al. (1990) at. 34.5 MHz and .Jones and Finlay (1974) at 29.9 MHz. The result confirms that the absorption model of the synchrotron emissivity in the Galactic plane is broadly corrected and illustrates the potential of the absorption technique.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.122-125
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• 2005

The AutoForm previously used the membrane element and it accomplished sheet metal forming analysis. The membrane analysis has been widely applied to various sheet metal forming processes because of its saving time effectiveness. However, it's well known that the membrane analysis can not provides correct information for the processes which considerable bending effects. From this time research it tried to compare the formation analysis result which uses the shell element which is applied newly in the AutoForm and actual products. The shell element is compromise method between continuum analysis and membrane analysis. The Finite element method by using shell element is the most economical numerical method. From analysis results, FEA by using shell element can estimate accurately the problems happened in actual auto-body panel.

• Journal of The Korean Astronomical Society
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• v.53 no.6
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• pp.169-179
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• 2020

Emission features formed through Raman scattering with atomic hydrogen provide unique and crucial information to probe the distribution and kinematics of a thick neutral region illuminated by a strong far-ultraviolet radiation source. We introduce a new 3-dimensional Monte-Carlo code in order to describe the radiative transfer of line photons that are subject to Raman and Rayleigh scattering with atomic hydrogen. In our Sejong Radiative Transfer through Raman and Rayleigh Scattering (STaRS) code, the position, direction, wavelength, and polarization of each photon is traced until escape. The thick neutral scattering region is divided into multiple cells with each cell being characterized by its velocity and density, which ensures flexibility of the code in analyzing Raman-scattered features formed in a neutral region with complicated kinematics and density distribution. To test the code, we revisit the formation of Balmer wings through Raman scattering of the far-UV continuum near Lyβ and Lyγ in a static neutral region. An additional check is made to investigate Raman scattering of O vi in an expanding neutral medium. We find a good agreement of our results with previous works, demonstrating the capability of dealing with radiative transfer modeling that can be applied to spectropolarimetric imaging observations of various objects including symbiotic stars, young planetary nebulae, and active galactic nuclei.

• Coupled systems mechanics
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• v.12 no.2
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• pp.183-197
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• 2023

Scarce research has been published on crack propagation fracture of flywheels manufactured with carbon fiber-reinforced polymers. The present work deals with a calculation method to determine the conditions for which a crack propagates in the axial direction of the flywheel. The assumptions are: flywheels made with just a single thick ply or ply clustering laminates, oriented following the hoop direction; a single crack is analyzed in the plane defined by the hoop and axial directions; the crack starts close to one of the free edges; its axial length is initially large enough so that its tip is far away from that free edge, and the crack expands the entire circumferential perimeter and keeps its concentric position. The developed method provides information for a good design of flywheels. It is concluded that a fracture-based crack propagation criterion generally occurs at a lower speed than a stress-based criterion. Also, that the evolution of failure with thickness using the fracture criterion is exponential, demonstrating that thin flywheels are relatively not sensitive to crack propagation, whereas thick ones are very prone.