• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.2
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• pp.288-298
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• 1999

In spark ignited engines, the electrical spark not only sets the time for the onset of combustion but also is able to greatly influence the character of the initial flame growth and the subsequent combustion, and thereby can influence engine performance. The relative importance of the ignition energy is particularly high under lean or high residual gas or exhaust gas recirculation (EGR). In this study, a modeling of flame Initiation and its development is proposed. Submodels consist in representing of cylinder pressure and temperature, heat transfer to cylinder wall, and flame kernel heat transfer to ambient air and to spark plug electrodes. The breakdown process and the subsequent electrical power input initially control the kernel growth while intermediate growth is mainly dominated by diffusion or conduction. Then, the flame propagates by the chemical energy, and laminar and turbulent flame velocity.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.2
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• pp.40-51
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• 1998

Electron transport properties are investigated by Monte Carlo simulation in n-HgCdTe. The material is easily degenerated at low temperature or being slightly doped, and is characterized by small band gap and large nonparabolic factor. The degeneracy is incorporated in the Monte Carlo simulation by taking into account the electron-electron scattering and the pauli exclusion principle. In the conventional method, however, the electron-electron scattering rate was developed under the assumption of parabolic conduction band. A new formulation of the electron-electron scattering rate is develop considering the band nonparabolicity and overlap integral. The electron-electron scattering effects on the electron distribution,impact ionization coefficienty, electron temperature, drift velocity and electron energy are presented.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1997.03a
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• pp.148-152
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• 1997

A numerical method is presented to predict and analyze the shape and the temperature history of a growing billet produced form the "spray forming" which is a fairly new near net-shape manufacturing process. It is important to understand the mechanism of billet growing and the cooling history of the spray deposited body, because one can obtain a billet with the desired final shape without secondary operations by accurate control of the billet shape and, moreover, growing velocity together with the cooling rate define the microstructure of the final formed product. In the present study, a theoretical model is first established to predict the shape of the billet and next the transient axisymmetric heat conduction problem with growing domain is solved using the so called "front tracking finite element technique".ent technique".uot;.

• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.77-79
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• 2007

The purpose of this study was to suggest a new detection method for early diagnosing diabetic neuropathic foot by obtaining a ratio of toe to figer blood flow using photoplethysmography(PPG). Nerve conduction velocity (NCV) has been routinely used for diagnosing neuropathic foot, but it applies strong electric stimulus to peripheries resulting in stress and pain. The blood flow ratio of diabetic neuropathy(0.96${\pm}$0.20) was significantly higher in comoarison to normal control group(0.46${\pm}$0.15, left : p<0.05, right : p<0.05) and non-neuropathy diabetic group(0.49${\pm}$0.21, left: p<0.05. right: p<0.05).

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.6 s.249
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• pp.514-522
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• 2006

This study has been performed to predict the transient thermal behavior of the plate in indirectly-fired continuous heat treatment furnace. The temperature profiles in the plate are determined solving the transient one-dimensional heat conduction equations. To verify the validity of the present numerical results, the present results obtained from the transient analysis are compared with those of experiments. Extensive parametric investigations are performed to examine the effects of the emissivities of the plate and refractory, plate thickness and velocity, as well as the gas temperature, on the thermal behavior of the plate.

• The Journal of Korean Physical Therapy
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• v.16 no.3
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• pp.72-85
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• 2004

We have few assessment tool in physical therapy. Recently, there is increasingly a concern of electrophysiologic examinations. They includes electomyography; needle and surface, evoked potentials; somatosensory evoked potentials; brainstem auditory evoked potentials; visual evoked potentials, nerve conduction velocity, blink reflex, H-reflex, and F-wave. The purpose of this study is understanding of electrophysiologic examinations. So we hope many physical therapist to use electrophysiologic examinations in research.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.5
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• pp.348-355
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• 2001

The coupled conduction and convection heat transfer from a protruding heated module in a horizontal channel with a variation of channel height is experimentally investigated. The input power to the module is 3, 7W and thermal resistance of module support is 0.06 , 1.03 and 158K/W. the Reynolds number ranged from 350 to 4500 corresponding to the inlet velocity(0.4~1.3 m/s) and channel height(11~35 mm). The results were obtained that the decrease of thermal resistance of module support reduces the module temperature by redistributing the heat flux and the overall thermal resistance of the module. In the study the effect of channel height is very significant in the adiabatic condition, but negligible in the conjugate condition. Finally, correlations for Nusselt number and $Q_B$/Q with a variation of Reynolds number were developed respectively.

• The Journal of Korean Physical Therapy
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• v.12 no.2
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• pp.249-254
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• 2000

The neuromuscular reaction can be delayed and velocity of nerve conduction can be slowed with aging. General activities ate changed to be slowly due to the decreased proprioceptor. The exercise for preventing aging in sites of the muscle strengthening exercise for maintaining the ability of activity. balance exercise for preventing from falling down and breathing exercise for the ability of respiration. The exercise have to be done without caring about the place and time. also have to be done enjoyably than competitively.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.5
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• pp.600-609
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• 1998

The experimental investigation of thermal response characteristics by the air flow through the porous media has been carried out. The packed spheres of steel or glass were considered as the porous media in the present study. Temperature distributions of the fluid in the porous media as well as pressure drops through the porous media were measured. The transient temperature variations in the porous media are compared favorably with the analytical results in the high Reynolds number ranges. However, in the low Reynolds number ranges, the experimental data deviate from the analytical results, due to the dominant heat conduction penetration to the upstream direction, which is not considered in the analytical model. The cool-down response of porous media is found to be dependent upon the specific dimensionless time considering the material property and air velocity. The heat discharge process is recommended to be operated until a certain time, considering the cost efficiency.

• Journal of Industrial Technology
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• v.25 no.A
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• pp.75-80
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• 2005

A trapezoidal fin is analyzed by using one-dimensional analytic method. For two boundary conditions, the heat transfer rate is given instead of specified temperature at the fin base and heat conduction into the fin tip is equal to heat convection from the tip. Temperatures at three different points within the trapezoidal fin are measured by using experimental apparatus. A comparison of the temperature between one-dimensional analytic method and experimentation is made as a function of dimensionless fin length under both free convection and forced convection conditions. The ratio of heat loss from the fin tip surface to that through the fin base is presented as a function of dimensionless fin length and Biot number. One of results shows that the relative error increases as the air velocity increases for forced convection conditions.