• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.6
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• pp.113-118
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• 1999

In order to evaluate strength of spot welded joint, at first it is importent that we should know strain distribution near nugget zone. During loading, in HAZ, compressive strain increase with Increase of load, but in nugget zone tensile strain increase. During unloading, on the other hand, even through the decreases, the strain variation is not almost appeared in nugget zone and HAZ. In nugget boundary zone, the strain range increases continuously along with load increase on outer surface, but the strain increases continunously and decreases rapidly beyond yield strength on inner surface. In this paper, strain distribution are measured in inner and outer surface with variation of thickness and load under tensile-shear load. Tensile-shear strength increased as with increase of specimen thickness. As for thickness increase rates are 25%, 50%, 100%, and 150%, tensile-shear strength in crease rates are 40%, 81%, 130% and 228%.

• Journal of the korean Society of Automotive Engineers
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• v.10 no.1
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• pp.26-32
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• 1988

A study has been conducted experimentally on the natural convection heat transfer characteristics of fin arrays on a horizontal flat plate in air. The effects of fin heights and Rayleigh numbers are mainly investigated. The experimental results are as follows; 1. The mean fin and mean total Nusselt numbers increase as dimensionless fin heights increase at 0.67.leg.H/s.leg.1.67. The mean plate Nusselt numbers increase in case of upward facing fins, but they decrease in case of downward facing fins. 2. The mean Nusselt numbers increase as Rayleigh numbers increase. 3. The mean fin surface Nusselt numbers has its maximum outside surface (Y$_{1}$) where there is no interference from each other fin. 4. The mean total Nusselt numbers in case of upward facing fins increase by 47% and 26%, respectively at H/S=0.67 and 1.67 than those in case of downward facing fins for Ra$_{s}$=6.50*10$^{3}$.>.

• Journal of Technology Innovation
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• v.13 no.3
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• pp.101-129
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• 2005

We decompose the patent increase over the period 1982 through 2000 using the data provided by KIPO(Korean Intellectual Property Office) and also compare our results to U.S. experiences. First, we show that the contribution of the increase in the R&D spending accounts for $71\%$ of patent increase between 1982 and 2000. Second, an overall increase in patent intensity measured by patent-R&D ratio between 1982 and 2000 is explained by $234\%$ of the changes in the patent yields in individual industries rather than by the reallocation of resources. Third, we find that there is structural change in patent intensity and patenting between 1994 and 1995. The patent yields in individual industries account for $86.4\%$ of patent increase between 1994 and 1995. Fourth, two high tech fields, electrical machinery and precision instrument, account for about $80\%$ of the patent increase.

• Proceedings of the Korean Quaternary Association Conference
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• 2004.06a
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• pp.29-29
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• 2004

Long term observational analysis by climatologists has confirmedthat the global warming is no longer a topic of debate among scientists andpolicy makers. According to the report of IPCC-2001 (Intergovernmental Panelon Climate Change), the global mean surface air temperature is increasinggradually. The reported increase of mean temperature is by 0.6 degree in the end of twentieth century. This could represent severe threat for propertylosses especially due to increase in the number of extreme weather arising out of global warming. period of model integration from 2001 to 2100 using output of ECHAM4/HOPE-G of Max Planet Institute of Meteorology (MPI) for IPCC SRES (Special Report on Emission Scenarios). The main results of this study indicate increase of surface air temperature by 6.20C and precipitation by 2.6% over Korea in the end of 21st century. Simulation results also show that there is increase in daily maximum and minimum temperatures while decrease in diurnal temperature range (DTR). DTR changes are diminished mainly due to relatively rapid increase of daily minimum temperature than that of daily maximumtemperature. It has been observed that increase in precipitation amount anddecrease in the number of rainy days lead to increase of pre precipitationintensity.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.7
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• pp.2289-2297
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• 1996

Flows in the combustion chamber near the spark plug are measured using LDv.A single cylinder DOHC S.I. engine of compression ratio 9.5:1 with a transparent quartz window piston is used. Combustion chamber shape is semi-wedge type. Measured data are analyzed using the ensemble averaged analysis and the cycle resolved analysis which uses FFT Filtering. Turbulent intensity and mean velocity are studied in the main flow direction and the normal to main flow direction as a function of engine speeds. The results shows that the turbulent intensity obtained by the ensemble averaged analysis is greater than that calculated by the cycle resolved analysis. Especially, the ensemble averaged analysis shows increase in turbulence at the end of compression stroke although the cycle resolved analysis shows increase only in the cycle-by-cycle variation with no noticeable increase in turbulence. The mean velocity in the main flow direction increase as engine speed increase. But the mean velocity normal to the main flow does not show such increase. Turbulent intensity in both direction increase in proportion to engine speeds. The magnitude of turbulent intensity is about 0.3 ~ 0.4 times the mean piston speeds at the end of the compression stroke.

• The Journal of Korean Medicine
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• v.17 no.1 s.31
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• pp.146-170
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• 1996

This study aimed to evaluate the anti-stress effects of Walgukhwan, Walgukhwan+Ejintang and Wal gukhwan+Samultang. The experimental animals treated with each extracts during 15 days before the immobilization stress. And each experimental animals were endowed with 12 hours immobilization stress. Then the brain, blood and urine catecholamine contents and serum total cholesterol, triglyceride and free fatty acid levels were studied. The result were as followed; 1. Walgukhwan, Walgukhwan+Ejintang and Walgukhwan+Samultang were not statistically effective to the changes of the body weight. 2. Walgukhwan was statistically effective to the increase of the blood norepinephrine content as compared with control. 3. Walgukhwan+Ejintang was statistically effective to the increase of the blood and urine norepinephrine contents as compared with control. 4. Walgukhwan+Samultang was statisticallv effective to the increase of the brain, blood and urine norepinephrine contents and also to the increase of the blood and urine dopamine contents as compared with control. 5. Walgukhwan was statistically effective to the increase of the serum free fatty acid level as compared with control. 6. Walgukhwan+Ejintang was statistically effective to the increase of the serum triglyceride and free fatty acid levels as compared with control. 7. Walgukhwan+Samultang was statistically effective to the increase of the serum total cholesterol, triglyceride and free fatty acid levels as compared with control.

• Journal of Acupuncture Research
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• v.22 no.2
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• pp.203-210
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• 2005

Objectives : The purpose of this study was to investigate anti-cancer effects of various ginseng herbal acupuncture in mice and expression of cytokine mRNA. Methods: Anti-cancer effects of various ginseng herbal acupuncture were tested by measuring the increase of life span of mice suffering from peritoneal cancer induced by Sarcoma-180, and expression of mRNA manifestation using RT-PCR. The results are as follows: Results: 1. Increase of life span of mice suffering from peritoneal cancer induced by Sarcoma-180 was measured for anti-cancer effects. As a result, 115% increase was shown in the cultivated wild ginseng group, 11.1% increase in the red ginseng group, and no increase was detected in either white ginseng and fresh ginseng groups. 2. Measuring the expression of cytokine mRNA manifestation, expression of $interferon-{\gamma}$ was slightly increased in the cultivated wild ginseng group compared to the control group, but manifestation of interleukin-10 was slightly decreased. 3. For the red ginseng, white ginseng, and fresh ginseng experiment groups II, IL-2, IL-4, $INF-{\gamma}$, and IL -10 all showed increase suggesting possible error occurring during the test process. Conclusion: From the results obtained in this study, we can reason that the ginseng we use may not match the ginseng cited in the texts of the past. Anti-cancer effects of cultivated wild ginseng can be more potent than those of white and fresh ginseng.

• Journal of Korea Foundry Society
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• v.12 no.6
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• pp.450-457
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• 1992

The study aims to investigate the influence of alloying elements(V,Ti) and heat treatment on the mechanical properties in hypo-eutectic chromium cast iron. Before heat treatment, all of the specimen were fully annealed(950$^{\circ}C{\times}5Hr$) to homogenize their structures. The influence of heat treatment and alloying elements(V,Ti) on hardness, retained austenite volume, and charpy impact energy as well as tensile strength of the specimen was tested systematically. Retained austenite decreased with the increase of V and Ti, but incresed with the increase of number of cycles. The impact energy decreased, and hardness and tensile strength increased with the increase of alloying elements (V,Ti) and the decrease of the number of cycles. The hardness and tensile strength increased, but impact energy decreased with the increase of V and Ti elements and the temperature of destabillization heat treatment. After the destabillization heat treatment at the same temperature, the impact energy is increased, while hardness and tensile strength decreased as the increase of tempering temperature. Retained austenite increased with increase of destabilizatoin heat treatment temperature, while decrease with the increase of tempering temperature.

• Nuclear Engineering and Technology
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• v.51 no.4
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• pp.1017-1023
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• 2019

The increase of the alternate current frequency results in increased rotational speed of the electrical motors and connected pumps. The consequence for the reactor coolant pumps is increased flow in primary coolant system. Increase of the current frequency can be initiated by the subsynchronous resonance phenomenon (SSR). This paper analyses the implications of the SSR and consequential increase of the frequency on the nuclear power plant safety. The Simulink $MATLAB^{(R)}$ model of the steam turbine and governor system and RELAP5 computer code of the pressurized water reactor are used in the analysis. The SSR results in fast increase of reactor coolant pumps speed and flow in the primary coolant system. The turbine trip value is reached in short time following SSR. The increase of flow of reactor coolant pumps results in increase of heat removal from reactor core. This results in positive reactivity insertion with reactor power increase of 0.5% before reactor trip is initiated by the turbine trip. The main parameters of the plant did not exceed the values of reactor trip set points. The pressure drop over reactor core is small discarding the possibility of core barrel lift.

• Geomechanics and Engineering
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• v.29 no.4
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• pp.451-461
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• 2022

The roadways surrounded by rock and coal will lose their stability or even collapse under rock burst. Rock burst mainly involves an evolution of dynamic loading which behaves quite differently from static or quasi-static loading. To compare the dynamic response of coal and rocks with different static strengths, three different rocks and bituminous coal were selected for testing at three different dynamic loadings. It's found that the dynamic compression strength of rocks and bituminous coal is much greater than the static compression strength. The dynamic compression strength and dynamic increase factor of the rocks both increase linearly with the increase of the strain rate, while those of the bituminous coal are irregular due to the characteristics of multi-fracture and heterogeneity. Moreover, the absorbed energy of the rocks and bituminous coal both increase linearly with an increase in the strain rate. And the ratio of absorbed energy to the total energy of bituminous coal is greater than that of rocks. With the increase of dynamic loading, the failure degree of the sample increases, with the increase of the static compressive strength, the damage degree also increases. The static compassion strength of the bituminous coal is lower than that of rocks, so the number of small-scale fragments was the largest after bituminous coal rupture.