• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.3
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• pp.102-110
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• 2004

A design code validated against the thermal analysis results of CFD and published RTE code for a regeneratively cooled combustion chamber has been developed. The major function of the code is to predict the regenerative cooling performance and stress of the chamber wall. Adopted are the empirical correlation for the evaluation of the heat transfer coefficient of hot gas and coolant, and theoretical formula for the fin effect of the channel rib. The hot-gas-side wall temperature from the present code shows 100 K difference at most compared to RTE results. It shows less than 10 % difference for the heat flux thrall through the chamber wall and hot-gas-side convective heat transfer coefficient. The major cause of the wall temperature difference is due to the underestimation of the fin effect of the channel rib.

• Journal of Veterinary Clinics
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• v.18 no.1
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• pp.14-17
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• 2001

Recombinant interleukin-2 (IL-2) has demonstrated as an antineoplastic agent in mice and human, but the relatively low response rates observed in clinical trials. Therefore, the present study was undertaken in order to evaluate therapeutic activities of IL-2 for the establishment of therapeutic applications. At the onset of the experiment, normal C3H/HeN mice were injected with $3{\times}10^6$ RD-995 tumor cells, murine ultraviolet radiation-induced fibrosarcoma, subcutaneously. Beginning on day 25, experimental groups were treated with a 5-day course of IL-2 (subcutaneous injection of 30,000 IU every 12 hours for 5 days). The result of this experiment revealed that RD-995 tumor grew progressively in control mice. Subcutaneous IL-2 therapy decreased tumor growth until day 23, then the tumor grew progressively. No significant difference in the survival of IL-2 therapy decreased tumor growth until day 23, then the tumor grew progressively. No significant difference in the survival of IL-2 therapy decreased tumor growth until day 23, then the tumor grew progressively. No significant difference in the survival of IL-2 treated mice were observed compared with the control mice.

• The Journal of Information Systems
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• v.19 no.3
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• pp.75-103
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• 2010

This study analyzes a model appling value in the mobile learning. We investigate the interaction, ease of use, hedonic value, and utilitarian value considering importance factors in the mobile learning, and the customer values are found to influence the customer satisfaction. We analysis a relationship between these factors and the customer satisfaction, and the relationship between the customer satisfaction and the loyalty. Finally, we research difference among gender of the satisfaction on the mobile learning. To fulfill this purpose, the research model was designed from literature review, and the structural equation modeling technique was used to evaluate hypotheses. The major results of this study are as follows. First, the ease of use, hedonic value, and utilitarian value positively influenced the satisfaction, and the satisfaction had positive influences on the customer loyalty. But the interaction didn't have positive influence on the satisfaction. Second, gender difference was found for some path coefficient. Male user's interaction and ease of use has effect on the satisfaction, and Female user's hedonic value and utilitarian value have influenced the satisfaction. When it consider the market share or the growth potential of the mobile learning industry, the results of this study will provide the useful information to manage mobile learning.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.5
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• pp.450-457
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• 2003

In this paper, we studied the effect of asymmetrical 3rd order IMD of power amplifier due to changes in modulation frequency on IMD cancellation performance. The phase extraction method for determining asymmetric rate for phase distortion of IMD is proposed and the phase difference between lower and upper 3rd order IMD is measured by this method. The phase compensation circuit to decrease the phase difference is also designed and fabricated. From the measurement results using the phase compensation circuit applied to 5 W RF power amplifier fur PCS applications, the 3rd order IMD cancellation performance can be achieved up to 2-tone spacing 1.5 MHz (phase difference within 10$^{\circ}$).

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.1
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• pp.142-155
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• 1992

Numerical analysis is performed for the unsteady axisymmetric two dimensional phase change problem of freezing of water around a vertical tube. Heat conduction in the tube wall and solid phase, natural convection in liquid phase and volume expansion caused by density difference between solid and liquid phases are included in the numerical analysis. Existing correlation is used for estimating density-temperature relation of water, and the effect of volume expansion is reflected as fluid velocity at the interface and the free surface. As pure water has maximum density at 4.deg. C, it is found that there exists an initial temperature at which the flow direction reverses near the interface and by this effect the slope of interface becomes reversed depending on the initial temperature of water. By considering natural convection and solid-liquid density difference in the calculation, their effects on phase change process are studied and the effects of various parameters are also studied quantitatively.

• Journal of The Korean Society of Integrative Medicine
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• v.5 no.1
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• pp.85-92
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• 2017

Purpose : The purpose of this study was to investigate the effect of posture difference on respiratory function in cerebral palsy patients. Methods : Twenty-two cerebral palsy childrens were recruited this study. Respiratory Function test was measured with Cardio Touch 3000 and Micro Respiratory Pressure Meter. Cardio Touch 3000 was used to assess cerebral palsy childrens' forced vital capacity and forced expiratory volume at one second. Micro Respiratory Pressure Meter was to assess Maximum inspiratory pressure and Maximum expiratory pressure. Subjects had four respiratory functions measured in supine, slouched sitting, and elected sitting postures. Statistical analysis was used Paired t-test for within-group comparisons and Independent t-test for between-group comparisons. SPSS statistics Ver 20.0 was used for statistical anlysis and statistical significance was defined as a p-value less than 0.05. Result : The subjects' respiratory function according to posture showed significant difference in Forced Vital Capacity(FVC), Maximum Expiratory Pressure(MEP) and Maximum inspiratory pressure(MIP)(p<.05). Elected sitting posture had a positive effect on respiratory function than slouched sitting, supine. Conclusion : In conclusion, We could see that change of posture in children with cerebral palsy affects respiratory function and Elected sitting can be a positive help for the respiratory function of children with cerebral palsy.

• Restorative Dentistry and Endodontics
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• v.13 no.1
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• pp.151-158
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• 1988

The purpose of this study was to evaluate the effect of canal filling methods and post-space preparation time on the apical seal of endodontically treated teeth. Seventy-six single-rooted human teeth were divided into 6 groups and each tooth was obturated and prepared post-space according to the purpose of this study. After all specimens were immersed in Indian ink, decalcified and cleared, the degree of dye penetration into the root canals observed by magnifying glass (X20) and measured by caliper. The results were as follows: 1. In the thermatic condensation, no significant difference in ink penetration occured when the post-spaces were created immediately after obturation or when they were made a week later. 2. In the lateral condensation, no significant difference in ink penetration existed between teeth whose post-space were prepared immediately or delayed. 3. In comparison of experimental groups and control groups, no significant difference showed when the groups were obturated with McSpadden compactor but when the teeth were laterally condensed, the experimental groups showed less ink penetration than controls. 4. Thermatic condensed teeth with McSpadden compactor were less ink penetration thn laterally condensed teeth.

• Journal of the Korean Society of Physical Medicine
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• v.5 no.4
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• pp.667-674
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• 2010

Purpose : The purpose of this study was to investigate the effect of motion-based game exercise program and stretching exercise program on static and dynamic standing balance in elderly women. Methods : Subjects participated in the exercise program was 40 eldery women took part in this study. The average age of the elderly was 70.60 years. All subjects could walk without an assistive device. All subjects were participated in this study during 4 weeks(3 days per week, 30min/day). All participants were assessed on berg balance scale(BBS), functional reach test(FRT), timed up&go test(TUG). Results : The data were analyzed using paired t-test. After 4 weeks exercise training, the result of this study were as follows: The BBS of the elderly was significant difference between test-retest(p<0.05). The TUG of the elderly were significant difference between test-retest(p<0.05). The Motion-Based game from FRT of the was more significant difference than stretching exercise program(p<0.05). we also found significant differences for both groups FRT scores, and changes in mean BBS, TUG scores, but BBS, TUG were not significant. Conclusion : We findings suggest that elderly women person could improve their standing balance through Motion-Based game exercise program, and stretching exercise program.

• The Journal of Korean Physical Therapy
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• v.25 no.5
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• pp.252-259
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• 2013

Purpose: The aim of this study was to evaluate the effect of progressive body weight decrease combined with increasing level of overground walking speed training for patients with chronic stroke. Methods: Eighteen subjects with chronic stroke were composed of the control group (5% body weight support combined with increasing speed training) and the experimental group (progressive body weight decrease with increasing speed training); three sets, three times per week over a period of four weeks. Results: Significant differences in terms of comfortable gait speed (CGS) and the rate of change of CGS were observed between the control and experimental groups (p<0.05). However, no significant difference in the dynamic gait index was observed between the control and experimental groups (p>0.05). A significant difference in the 6 minute walking test (6MWT) was observed for the experimental group, and a significant difference in the rate of change for the 6MWT was observed between the control and experimental groups (p<0.05). Conclusion: The progressive body weight decrease combined with increasing in level of overground walking speed training may be a better and more effective method for community walking and reintegration.

• Journal of the Korean Society of Hazard Mitigation
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• v.4 no.2 s.13
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• pp.13-18
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• 2004

In this study, in the first place, parameters primarily influencing displacement and stress were constructed by using the Finite Difference Method; then using those parameters, the result of crown displacement and convergence among the existing, experimental values of a centrifuge model were compared with the result of numerical analysis; and then considering the stress and time effect of lining installation, parameters according to the difference of stiffness were studied. In the result of this study, it found out that rough, ground reinforcement effect manifests itself when reinforcement propert of the grouting of the big scale steel pipe through 3-D analysis is E= 4,000tf/m2 which of the stiffness of the original ground.