• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.12
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• pp.1218-1226
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• 2004

This paper presents thermal behaviors and performances of a fresh air load reduction system by using earth tube system combined with air-heated solar collector. The earth tube system reduces a fresh air load by heat exchange with soil throughout the year. In the previous experimental research, it was clarified that the earth tube system was very useful as a fresh air load reduction system. However, since outlet temperature of the fresh air which was heated by earth tube system was below 15$^{\circ}C$ in winter, it is not suitable to introduce the fresh air into the place of residence directly. Therefore, a simulation model using the simple heat diffusion equation was used to examine a rising effect of outlet air temperature in winter by combining with air-heated solar collector. An improvement of annual performance by control of operation is also quantitatively examined. In conclusion, it is confirmed that its performance is improved by control of operation throughout the year and outlet air temperature rose by combining with air-heated solar collector.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.9
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• pp.870-878
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• 2000

An experimental study and a modeling are peformed to investigate the pressure drop of combining junctions in two-phase flows. Experiments on tripod geometry used in a condenser or an evaporator, are conducted with inlet mass fluxes from 200 to$ 400 kg/m^2$s, and pipe diameters of 7 m and 9.52 m. The working fluid is R22. The result shows that the pressure drop increases as the quality does, but the effect of the increase of the pressure decreases when the diameter of a pipe increases. When the mass flux increases, the pressure drop linearly does. Furthermore, when the pipe diameter decreases, the pressure drop has a quadratic increase.

• Journal of electromagnetic engineering and science
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• v.4 no.4
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• pp.175-182
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• 2004

When the M-ary signal experiences the Rayleigh fading, the diversity schemes can reduce the effect of fading since the probability that all the signals components will fade simultaneously is reduced considerably. The symbol error probabilities for various M-ary signals, such as MDPSK(M-ary DPSK) and MPSK(M-ary PSK), are mathematically derived for the Selection Combining 2(SC-2) and Selection Combining 3(SC-3) demodulation system which requires a less complex receiver than Maximum Ratio Combining(MRC). The propagation model used in this paper is the frequency-nonselective slow Rayleigh fading channel corrupted by the Additive White Gaussian Noise(AWGN). The numerical results presented in this paper are expected to provide information for the design of radio system using M-ary modulation method for above mentioned channel environment.

• Journal of electromagnetic engineering and science
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• v.7 no.4
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• pp.183-189
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• 2007

When the M-ary signal experiences the Rayleigh fading, the diversity schemes can reduce the effect of fading since the probability that all the signals components will fade simultaneously is reduced considerably. The symbol error probabilities for various M-ary signals, such as MDPSK(M-ary DPSK) and MPSK(M-ary PSK), are mathematically derived for the Selection Combining 2(SC-2) and Selection Combining 3(SC-3) demodulation system which requires a less complex receiver than maximum ratio combining(MRC). The propagation model used in this paper is the frequency-nonselective slow Rayleigh fading channel corrupted by the additive white gaussian noise(AWGN). The numerical results presented in this paper are expected to provide information for the design of radio system using M-ary modulation method for above mentioned channel environment.

• Journal of the Korean Society of Tobacco Science
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• v.4 no.1
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• pp.7-13
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• 1982

Six orient varieties of N.tabacum and 15 $F_1$ hybrids, not including reciprocal crosses, were evaluated for the degrees of heterosis and the combining abilities of 6 characteristics in Suweon, Korea, 1981. The values 9f general combining abilities tiers greater than those of specific combining abilities in all traits but significant SCA was also observed for Plant height, days to flowering and yield. In general, CCA effect was large in Samsun, Kavala and Izmir varieties. Large SCA values were observed for number of leaves in Samsun x Izmir, days to flowering in Samsun x Serves, leaf shape in Basma x Xantlli, and yield in Basma x Kavala and Xanthi x Izmir. Heterosis of favorable directions in $F_1$ was generally observed for all traits. Especially the $F_1$ of Samsun x Kavala flowered earlier than its midparents. Large heterosis effects were manifested for the number of leaves in Samsun x Izmir and yield in Samsun x Izmir as well as Xanthix Izmir.

• Journal of Nutrition and Health
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• v.27 no.10
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• pp.996-1006
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• 1994

This study was performed to investigate the effect of dietary chitin & chitosan on cadmium (Cd) toxicity and lipid metabolism in rats. Forty-two male rats of Sprague-Dawley strain weighing 137$\pm$2g were blocked into 6 groups according to body weight, and were raised for 4 weeks. Cadmium chloride was given at the level of 0 or 400ppm in diet and chitin and chitosan were given at the level of 0 or 4%(w/w) of diet. The results are summarized as follow. Chitosan decreased the toxicity of Cd on liver, kidney and femur and increase the Cd content of fecal excretion. Chitosan increased the lipdi & cholesterol content of fecal excretion by combining with lipid and bile acid. Chitosan decreased lipid, cholesterol and TG content in serum and liver by combining with lipid and bile acid. Chitin was less effective than chitosan in decreasing of Cd toxicity and lipid content of rat.

• Journal of Information Management
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• v.38 no.1
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• pp.1-19
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• 2007

This study investigates the effect of data fusion on the retrieval effectiveness by performing an experiment combining multiple representations of Web documents. The types of document representation combined in the study include content terms, links, anchor text, and URL. The experimental results showed that the data fusion technique combining document representation methods in Web environment did not bring any significant improvement in retrieval effectiveness.

• Herbal Formula Science
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• v.31 no.3
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• pp.203-213
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• 2023

Objectives : The purpose of this study is to report the symptomatic relief effect of a herbal prescription combined with methimazole for hyperthyroidism caused by Graves' disease. Methods : After diagnosis of hyperthyroidism, methimazole was initially administered alone. As the clinical symptoms continued, a herbal medicine combining Gamiondam-tang and Cheongsimyeonja-eum was administered together with methimazole. Blood concentrations of hormones were measured, and the degree of clinical symptoms was measured using the NRS scale. The effect of herbal medicine on heat intolerance was analyzed by Wilcoxon rank sum test, and the relationship between thyroid hormone and heat intolerance was analyzed by Pearson's correlation coefficient. Results : Heat intolerance symptoms were significantly reduced when the herbal prescription was administered in parallel than when methimazole was administered alone (w=296, p=0.001). The decrease in heat intolerance was not related to thyroid hormone levels (p=0.27, 0.37). Conclusions : It was found that the herbal medicine combining Gamiondam-tang and Cheongsimyeonja-eum was effective in treating hyperthyroidism symptoms including heat intolerance.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.7
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• pp.360-365
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• 2017

Recently, development efforts of triple-effect absorption chiller have been increased in order to improve the efficiency of double-effect absorption chiller. However, triple-effect absorption chiller has some disadvantages, including high corrosion characteristic of LiBr solution at high temperature of $200^{\circ}C$. Moreover, it is necessary to develop new components for operation under high pressure of 2 bars even though COP is increased to 1.6 or 1.7. The objective of this study was to introduce a new system by combining double effect absorption chiller with single effect absorption chiller with multi-generators using bypass flow of LiBr dilute solution to $3^{rd}$ generator to overcome the disadvantages of triple-effect chiller and improve energy efficiency. Results indicate that the new absorption cycle had a much higher efficiency than double-effect chiller system, showing significant improvement when bypass solution flow rate of 25% was applied to the $3^{rd}$ generator using the main dilute solution of the absorber. The COP of the new chiller system was found to be 1.438, which was 21.7% higher than that (1.18) of the present double-effect system. The COP was decreased when solution by-pass rate to the $3^{rd}$ generator was increased. In addition, lower cooling water temperature caused higher COP. Therefore, the multi-generator system with by-pass solution might be an excellent chiller alternative to triple-effect absorption chiller with higher efficiency.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.4 no.3
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• pp.25-30
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• 1995

A new finishing process, magnetic-electrolytic-abrasive polishing(MEAP), combining Lorentz' force effect in the traditional electrolytic finishing process was developed to realize the high efficiency as well as high surface quality of finishing . The paper describes the theoretical basis about the modification of electrolytic ions motion by the magnetic field. The effect of magnetic field on the electrolytic process was discussed was and analyzed from the result of model test.