• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2008년도 하계학술발표대회 논문집
• /
• pp.184-188
• /
• 2008

It has been recognized that friction coefficient decreased with decreasing viscosity of oil in lubrication. In general, the more viscosity decreases, the more wear rate increases due to decrease load carrying capacity. It has been proposed that nano particles in oil decrease friction coefficient and wear rate. The purpose of this study is to apply oil of lower viscosity that mix with nano particles at the compressor used in a refrigerator to decrease friction coefficient keeping Load carrying capacity. Mineral oil of 8 cSt were used and mixed with nano particle. Friction coefficient was evaluated by a disk-on-disk tester. As a result, friction coefficient of nano oil decreased by 90% in comparison with raw oil. These results lead us to the conclusion that nano oil is new plan to raise efficiency of the compressor.

• 한국환경보건학회지
• /
• 제1권1호
• /
• pp.5-8
• /
• 1974

A survey was carried out in order to figure out of phenomenon of increasing and decreasing rate of WBC during a day in normal and healthy person from Oct. 1, 1972 to Nov. 31, 1972. For this survey, it was classified by two groups 50 male students and 35 female students who are from 18 to 25 years old. The blood sampling was collected by thin smear method 8 times from 7:30 A.M. to 10:30 P.M. by 2 hours intervals and calculated by direct manual method. As the results of this survey, the following conclusions were obtained 1) Number of WBC was the lowest degree during the forenoon, and it was the highest degree around the midnight. It was increase from around the noon up to the midnight and decrease from the midnight up to around the noon. 2) Increasing and decreasing curve of WBC of male and female was keeping same pace with both sex in a day. 3) Increase and decrease of lymphocyte and eosinophil was keeping almost same pace with WBC. 4) Increasing rate of number of monocyte was more speedily increasing during the afternoon than the night.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2022년도 가을 학술논문 발표대회
• /
• pp.207-208
• /
• 2022

Since 1960, the green area has decreased due to rapid urbanization and the artificial surface has increased, and the repair and water function of the previous surface has decreased due to the decrease in rainwater absorption capacity. In addition, the risk of carbon dioxide and fine dust is emerging due to the use of fossil fuels due to urbanization. As a result, permeable blocks, an eco-friendly product, are in the spotlight. Therefore, this study was conducted to examine the strength properties of the permeable block using a hydroball. As a result of the experiment, the flexural strength and compressive strength tended to decrease as the hydroball replacement rate increased. It is judged that the hydroball absorbs a large amount of moisture during the mixing process and lacks moisture required for curing, resulting in a decrease in strength. According to KS F 4419, since the hydroball replacement rate is satisfied up to 20%, further research is needed to analyze the adsorption performance of air pollutants in the future and evaluate their utilization as a permeable block in the future.

• 대기
• /
• 제34권2호
• /
• pp.107-121
• /
• 2024

In this study, we empirically analyzed the impact of physical risks due to climate change on the soundness and operational performance of the financial industry by combining economics and climatology. Particularly, unlike previous studies, we employed the Seasonal-Trend decomposition using LOESS (STL) method to extract trends of climate-related risk variables and economic-financial variables, conducting a two-stage empirical analysis. In the first stage estimation, we found that the delinquency rate and the Bank for International Settlement (BIS) ratio of commercial banks have significant negative effects on the damage caused by natural disasters, frequency of heavy rainfall, average temperature, and number of typhoons. On the other hand, for insurance companies, the damage from natural disasters, frequency of heavy rainfall, frequency of heavy snowfall, and annual average temperature have significant negative effects on return on assets (ROA) and the risk-based capital ratio (RBC). In the second stage estimation, based on the first stage results, we predicted the soundness and operational performance indicators of commercial banks and insurance companies until 2035. According to the forecast results, the delinquency rate of commercial banks is expected to increase steadily until 2035 under assumption that recent years' trend continues until 2035. It indicates that banks' managerial risk can be seriously worsened from climate change. Also the BIS ratio is expected to decrease which also indicates weakening safety buffer against climate risks over time. Additionally, the ROA of insurance companies is expected to decrease, followed by an increase in the RBC, and then a subsequent decrease.

• 한국경영과학회지
• /
• 제11권2호
• /
• pp.7-12
• /
• 1986

The problem of strategic R & D investment is formulate as a differential game model and solved explicity for a special case. It is shown that, at equilibrium, an increase in the intensity of market competition or a decrease in the role of technology transfer results in an increase in the initial rate of investment by competing tfirms. The increased initial investment rate may enhance the rate of technology development. This dynamic model can be used to propose non cooperative R & D investment policies in technologically competitive situation.

• Biotechnology and Bioprocess Engineering:BBE
• /
• 제7권2호
• /
• pp.117-120
• /
• 2002

The effect of cell density on cell growth was investigated in a suspension batch culture of hybridoma cells. The specific growth rate was found to increase with increasing initial cell density and then to decrease with further increases in initial cell density. In order to quantitatively describe the dependence of specific growth rate on cell density, a kinetic model is proposed, which satisfactorily represents the experimental data.

• 한국동물위생학회지
• /
• 제20권1호
• /
• pp.1-9
• /
• 1997

The 37,000 holstein which had been raised in Jeju island were examined for the purpose of brucellosis detection and so on. We investigated the relationship between the farms showing positive outbreak and the number of examination, incubation period, and the outbreak rate of positive cattle. We endeavored to separate germs from brucellosis positive cattles blood and negative bulls semen against brucellosis serum test and concluded as follows. We intend to offer you institutional supplements and preventions of brucellosis for the future. 1. Outbreak of brucellosis could not lead the outbreak rate of positive cattle to decrease through 1-2 examination per year, For the past 4 years, the outbreak rate of brucellosis positive cattle had a tendency to show a gradual decrease through at least 5 examinations per year. 2. As we examined live-in cattle with positive cattle in mass outbreak farms for 9 months, we found out positive cattle every month. In a grazing land, the group of cattle producd enormous positive cattle in 9-12 months. 3. Annual brucellosis positive outbreak rate was 20-25% among live-in cattle with brucellosis positive cattle, but the rate might be 50-100% depending on extent of pollution. 4. 94's brucellosis examination showed that 200 positive cattle of 71,153 cattle and most of them were live-in cattle with confirmed brucellosis positive cattle. 5. 1 head of 200 positive cattle showed positivity against serum of bulls test and the rate of bulls was about 1%. 6. Brucellosis germ was separated from 2 cattle's semen among 52 negative bulls against brucellosis serum test and there was the one brucellosis positive cattle against tube agglutination of semen test, so the positive rate of brucellosis was 5.8%. 7. Brucellosis germ was not separated from 15 brucellosis positive cattle's blood.

• 방송공학회논문지
• /
• 제17권3호
• /
• pp.480-490
• /
• 2012

H.264/AVC 표준은 색차 신호를 보간할 때 선형 보간을 이용하여 예측 보간 신호를 생성한다. 휘도 신호의 예측 보간에 사용되는 6탭 FIR 필터, 2탭 선형필터, 고정밀도 필터의 조합은 선형 예측 보간에 비해서 더 정확한 예측 값을 생성할 수 있다. 본 논문에서는 휘도신호의 예측 보간에 사용되는 6탭 FIR 필터, 2탭 선형 필터, 고정밀도 필터를 색차신호의 예측보간에 사용하여 부호화 효율을 높이는 방법을 제안하였다. 실험 결과, 제안하는 방법은 jm11.0kta2.7 과 비교하여 PSNR의 감소없이 BD-Rate의 감소를 확인하였다. Y는 최대 1.3%, Cb는 최대 19.8%, Cr은 최대 25.0%의 BD-Rate의 감소를 확인 할 수 있었다. 평균적으로 Y는 0.5%, Cb는 6.1%, Cr는 6.9%의 BD-Rate의 감소를 확인하였다.

• Environmental Analysis Health and Toxicology
• /
• 제3권1_2호
• /
• pp.43-54
• /
• 1988

Experiment was performed to investigate the immunotoxicity of cadmium administered orally and the effect of ginseng petroleum ether fraction on it. Mice were given 3, 30, or 300 ppm cadmium as cadmium chloride orally in the drinking water and injection of ginseng petroleum ether fraction intraperitoneally for 4 weeks. Mice were sensitized and challenged with sheep red blood cells (S-RBC). Humoral immune response was evaluated by antibody production and Arthus reaction. Body weight gain, spleen weight, thymus weight, and liver weight were also measured. In the present study, cadmium generally suppressed the humoral immunity. There was decrease in the rate of body weight gain and liver weight to body weight by cadmium-administration. Ginseng petroleum ether fraction showed restoring effect, to some extent, on the decrease in PFC and in the rate of liver weight to body weight by cadmium-administration. But it more suppressed Arthus reaction.

• 한국해양공학회지
• /
• 제6권1호
• /
• pp.140-147
• /
• 1992

Corrsion fatigue test was performed under rotated bending in 3.5% NaCl aqueous solution having a temperature from 278.deg.K in order to investigate the effects of aqueous solution remperature on the corrosion fatigue fracture of raw material steel(SS41) and dual phase steel that was produced from SS41 by a series of heat treatment. Corrosion fatigue life decreases remarkably with increase in solution temperature or with decrease in stress level. The corrosion fatigue life and the crack propagation rate at 303.deg.K show the similar behaviors with those at 318.deg.K, which is assumed to be caused by concentration polarization phenamena. The number and the lengths of microcracks increase with increase in solution temperature, so they lead to the decrease in corrosion fatigue life.