• 한국수소및신에너지학회논문집
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• 제14권3호
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• pp.187-194
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• 2003

The production of hydrogen fuel depends basically on the water electrolysis. The study on the decrease of overpotential which activates the hydrogen production is the core to elevate the hydrogen production efficiency on principle. Characteristics on the overpotential decrease are observed through the micro reaction by ultrasonic in electrolytic cell. For the above, the electrochemical analyzer, i.e., BAS is applied, Experiments with ultrasonic forcing into 4 kinds of solution such as city water, city water plus nitrogen. distilled water, and distilled water plus nitrogen are carried out. And concentrations of KOH are 0%, 10%, 20% and 30%. The basic characteristics of the overpotential decrease are obtained through the analysis by LSV technique in sweep technique. In results, it is clarified that the ultrasonic influences the decrease of overpotential to obtain the efficiency elevation of hydrogen fuel production.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2003년도 유체기계 연구개발 발표회 논문집
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• pp.92-98
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• 2003

Turbine blades experience significant surface degradation with service. This paper presents experimental evidence of blade surface roughness reducing turbine efficiency. Performance tests were conducted in a low speed, single-stage axial flow turbine rig with roughened blade surfaces. Sheets of sandpaper with equivalent sandgrain roughnesses of 106 and $400{\mu}m$ were used to roughen the blades. In these tests, effects of roughened stator vanes and rotor blades were separately evaluated. In the fully rough regime ($k_{s}=400{\mu}m$), the experimental results show an 11 percent decrease in normalized efficiency with roughness only on stator vanes ; an 8 percent decrease with roughness only on rotor blades ; and a 19 percent decrease with roughness on both the stator and rotor blades. In the transitionally rough regime ($k_{s}=106{\mu}m$), the trends are similar approximately 4 percent decrease with either roughened stator or roughened rotor and an 8 percent decrease with roughness on both stator and rotor blades. Thus, roughened stator vanes incur more performance penalty than roughened rotor blades.

• 아태비즈니스연구
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• 제9권4호
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• pp.85-97
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• 2018

This paper investigates factors underlying a decrease in trading values in KOSPI 200 futures/options market on the basis of the current state of the markets. Among the factors that could affect trading values in KOSPI 200 derivatives market, we focus on the market activity of underlying assets as it has an impact on the trading of financial derivatives. Trading value and volatility are designated as market activity and the empirical results confirm that the market activity of the underlying assets is significant in explaining the decrease in trading values in KOSPI 200 futures/options market. To figure out fundamental reasons of the decrease in trading values in this market, we examine mitigation of home bias and decrease in leverage incentives as they are presumed to have influence on KOSPI 200 index market. As the global and local financial environment is time-varying, the degree of home bias and the leverage demand also changes. It implies that institutional change and/or policy effort to promote the trading of KOSPI 200 financial derivatives should be made taking into account the fact that considerable portion of the change in trading values in financial derivatives market depends on the state of the market.

• KDI Journal of Economic Policy
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• 제44권2호
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• pp.45-71
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• 2022

This paper studies potentially relevant factors affecting changes in the number of self-employed in Korea during the period of 1986-2018. The number of self-employed had increased steadily until 2002 but started to decrease around that time and had continued to decline. The increasing trend in the number of self-employed during 1986-2001 is mostly explained by demographic changes, whereas the declining trend during 2002-2018 cannot be explained by demographic factors. In this study, I consider four institutional factors that potentially affect the decrease in the number of self-employed after 2002: i) a decrease in the job-separation rate of wage workers, ii) an increase in the income tax rate applied to the self-employed, iii) an increase in minimum wages, iv) an expansion of unemployment insurance benefits. Using a search and matching model with the self-employed, I quantify the effects of these four factors on the decrease in the number of self-employed during 2002-2018. Quantitative results show that the impact of the increase in the minimum wage is relatively large, whereas the effects of the other three factors are limited. The increase in the minimum wage accounts for approximately 17.5% (0.169 million) of the decrease in the number of self-employed during 2002-2018 (0.964 million).

• 혜화의학회지
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• 제8권1호
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• pp.593-623
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• 1999

This experimental study was designed to verify the anti-aging efficacy of Eukmigihwangtang (EMGHT) and Rehmannia Radix, and determine the specific role and actions of Rehmannia Radix. Normal rat (2 months old), aging rat (8 months old), and pathologically induced rat (2 months old, injected 30mg/kg of streptozotocin) are observed to study the aging eliciting factors such as peroxide contents and enzyme activities. The following results were obtained in this study: 1. For the body weight changes, normal group given Rehmannia Radix showed decrease in the body weight compared to the control group, aging group given EMGHT and Rehmannia Radix showed significant decrease in the body weight, and STZ injected group showed suppression to the body weight loss when given EMGHT and Rehmannia Radix. 2. For the content changes in serum lipid peroxide, normal group showed increasing level as the rat gets older. Aging group and STZ injected group given EMGHT and Rehmannia Radix showed significant decrease in the lipid peroxide level compared to the control group. Decrease was more prominant in the group given EMGHT. 3. For the changes in serum hydroxyl radical, normal group did not show significant changes, but aging group and STZ injected group given EMGHT and Rehmannia Radix showed significant decrease in the hydroxyl radical level compared to the control group. Decrease was more prominant in the group given EMGHT. 4. For the changes in serum superoxide dismutase (SOD) activity, normal group did not show significant changes, but aging group given EMGHT and Rehmannia Radix showed significant increase in the SOD activity compared to the control group. STZ injected group given EMGHT and Rehmannia Radix showed significant decrease in the SOD activity compared to the control group. 5. For the content changes in hepatic lipid peroxide, aging group and STZ injected group given EMGHT and Rehmannia Radix showed significant decrease in the lipid peroxide level compared to the control group. 6. For the changes in hepatic cytochrome P-450 activity, aging group and STZ injected group given EMGHT and Rehmannia Radix showed significant decrease compared to the control group. Cytochrome b5 activity was significantly decreased only in the STZ injected group given EMGHT and Rehmannia Radix. 7. For the changes in hepatic aminopyrine demethylase and aniline hydroxylase activity, aging group given EMGHT and Rehmannia Radix showed significant decrease compared to the control group. STZ injected group given EMGHT and Rehmannia Radix showed significant increase in the aminopyrine demethylase activity, and showed significant decrease in the aniline hydroxylase activity compared to the control group. 8. For the content changes in hepatic protein bound-SH and nonprotein bound-SH, againg group and STZ injected group given EMGHT and Rehmannia Radix showed significant increase compared to the control group. 9. For the content changes in hepatic glutathione level, aging group and STZ injected group given EMGHT and Rehmannia Radix showed significant increase compared to the control group. 10. For the changes in hepatic glutathione S-transferase activity, aging group and STZ injected group given EMGHT and Rehmannia Radix showed significant increase and decrease, respectively, compared to the control group. 11. For the changes in hepatic glutathione reductase activity, aging group and STZ injected group given EMGHT and Rehmannia Radix showed significant increase compared to the control group, while $\gamma$-Glutamylcystein synthetase activity did not show significant changes. 12. For the changes in hepatic superoxide dismutase activity, aging group and STZ injected group given EMGHT and Rehmannia Radix showed significant decrease compared to the control group. From the above results, the antioxidant effects of EMGHT and Rehmannia Radix were proved, as well as the role of Rehmannia Radix, a chief of EMGHT, was examined. In addition, since no change was reconized as the quantity of Rehmannia Radix and the order herbs increased, the reasonableness on EMGHT was proven with respect to its composition and quantity. Thus, the significance of EMGHT could be objectively exmined in terms of its composition and quantity. Considering animals used in the experiment, there were obvious changes in aging rats and pathologically induced rats than in normal rats. Consequently, it was noticeable that EMGHT and Rehmannia Radix were working selectively on the subjects.

• 오토저널
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• 제5권1호
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• pp.89-93
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• 1983

This paper describes on experimental investigation into the heat dissipation of Diesel engine, placing emphasis on the variations of compression ratio and cooling water temperature. The engine used for this test was a vertical single-cylinder four-cycle type, having a direct injection. Engine performance and heat transfer rates was tested under the compression ratio 14.3 and 17.4. In this study, the results showed that output and transfer rates of engine decrease in accordance with the decrease of compression ratio. The effect of cooling water temperature and injection delay of fuel on the heat dissipation brings about the decrease of heat transfer rates from cylinder to cooling water.

• 대한약침학회지
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• 제4권3호
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• pp.93-99
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• 2001

Objective : This study was performed to examine the Herbal Acupuncture decrease the side effect of Bee Venom. Methods: We treated Bee Venom and various Herbal Acupuncture mixed Bee Venom using double blind test to 70th health youth, and checked pain, edema size, CBC, Serum biochemistry and Thermography. Results: 1. Herbal Acupuncture made by Morus bombycis Koidzumi showed good results to decrease the side effect of Bee Venom than any other Herbal Acupuncture. 2. We examined CBC, ESR and Serum biochemistry before and after treated. Special change was not showed. 3. We observed the pain and edema after treated Bee Venom and Morus bombycis Koidzumi Herbal Acupuncture mixed Bee Venom. We knew that Morus bombycis Koidzumi Herbal Acupuncture was decrease the pain and edema due to Bee Venom. 4. According to these clinical studies, Morns bombycis Koidzumi Herbal Acupuncture has a possibility to be a good partner of Bee Venom.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2002년도 학술.기술논문발표회
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• pp.55-58
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• 2002

This study is to analyze the influence of correction factor and specimen thickness on the fundamental properties of porous concrete. Results of this study were shown as follows; 1) As correction factor decrease, compaction time according to correction factor and specimen thickness decrease. Also, though correction factor is same, as specimen thickness increase, compaction time increase. So It mutt be considered that the influence of compaction time according to correction factor and specimen thickness. 2) As correction factor decrease, difference of measured thickness and designed thickness according to correction factor and specimen thickness decrease. Also, correction factor of aggregate of 10~l5mm is smaller than that of 5~l0mm. So It must be considered that the influence of correction factor according to size of aggregate.

• Biomolecules & Therapeutics
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• 제5권2호
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• pp.211-214
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• 1997

In the present study, we investigated the mechanisms of antinociceptive effect and thermoregulatory action of capsaicin in guinea pigs. The administration of capsaicin (5 mg/kg, s.c.) caused a significant decrease in frequency of eye wiping, an indicative of nociceptive threshold. This antinociceptive effect of calsaicin was abolished by co-administration of capsazepine (30 mg/kg, s.c.) with capsaicin, suggesting the involvement of a vanilloid receptor in the antinociceptive action of capsaicin. The administration of capsaicin (1 mg/kg, s.c.) produced a significant decrease in body temperature of guinea pigs. The maximum decrease in body temperature by 2 degrees was shown 1 hour after the treatment, and this decrease was not reversed by coadministration of capsazepine. In conclusion, it is suggested that the mechanism of action of capsaicin-induced thermoregulation involves different pathways from that of capsaicin-induced antinociception.

• 대한약리학회지
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• 제15권1_2호
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• pp.39-43
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• 1979

Piroxicam is known to be a new nonsteroidal anti-inflammatory drug which has anti-inflammatory, antiedema, antigranuloma and analgesic activities through the mechanism of inhibition of prostaglandin synthetase. Clinical survey for piroxicam was carried cut on 40 cases of rheumatoid arthritis and 30 cases of degenerative arthritis who visited University Hospital from Feb. to June, 1979. Following results could be obtained: 1) In rheumatoid and degenerative arthritis, the effect of piroxicam was significant in decrease of joint pain, shortening of duration of morning stiffness, decrease in number of swollen joints, improvement of joint stiffness, decrease of E.S.R., increase of mean grip strength and decrease of articular index. 2) Side effects, almost all in G-I troubles were encountered in 6 cases in 40 cases of rheumatoid arthritis and 4 cases in 30 cases of degenerative arthritis.