• 천문학논총
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• 제30권2호
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• pp.709-711
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• 2015

In modern Astronomy the vernal equinoctial (VE) point is taken as the starting point for measuring celestial longitudes. Due to the precession of equinoxes, the above point is receding back along the ecliptic. As a result, the longitudes of fixed stars are increasing every year. In ancient India, the Hindu astronomers did not favour the idea of fixed stars changing their longitudes. In order to stabilize the zodiac, they had taken as the origin a point which is fixed on the ecliptic and as such is quite different from the VE point. This initial point being a fixed one, the longitude of stars measured from this origin remain invariable for all time. There was an epoch in the past when this initial point coincided with the VE point and thus the epoch may be called the zero-year. There is controversy over the determination of the zero-year. The reasons for the choice for the fixed zodiacal system by the Hindu astronomers as well as the epoch of zero-year have been found out on the basis of information available in various astronomical treatises of ancient India written in Sanskrit.

• Journal of Periodontal and Implant Science
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• 제38권3호
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• pp.453-466
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• 2008

Purpose: The purpose of this research is to study about initial adhesion, proliferation and activation of osteoblast to titanium surface treated with machined, hydroxyapatite coating, resorbable blast material blasting and anodizing method. Material and Methods: After treating the titanium surface of each block with machined, impurities were removed and sterilized. The number of cells attached from cultured osteoblast of respective experimental groups were measured at 1, 4, 7, and 14day and alkaline phosphatase, calcium, and inorganic phosphate concentration of cultured solution was measured. Result: Anodizing group showed the highest rate of cell attachment and proliferation activity. RBM treated group showed the highest increasing on their alkaline phosphatase activity, on the calcium apposition, on inorganic phosphate apposition of 1 and 4 days in cultured osteoblast to compare with other groups. Conclusion: On the basis of these findings, we conclude that surface modification of titanium was profoundly effected on the attachment, proliferation and activation of osteoblast in initial stage osseointegration.

• 반도체디스플레이기술학회지
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• 제15권1호
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• pp.12-16
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• 2016

Toluene-free pressure sensitive adhesives were synthesized by using butyl acrylate (BA), 2-hydroxy ethyl acrylate, methyl methacrylate, acrylic acid (AA) as monomers and ethyl acetate as a solvent. The polymerization recipes were designed by changing 1, 3, 5 part per hundreds monomer (phm) of AA content on the basis of 100 BA parts. Two crosslinking agents, ethyl glycol diglycidyl ether (EDGE) and isophorone diisocyanate (IPDI) were added to the synthesized polymers to increase adhesion due to crosslinking. In the measurement of properties, holding power, peel strength, and initial tackiness increased with AA content due to crosslinking between carboxyl group in AA and epoxy group in EDGE and isocyanate group in IPDI. In the comparison of two crosslinking agents, EDGE showed better in the three properties than IPDI by better reaction of epoxy group of EDGE to carboxyl group of AA.

• 대한핵의학회지
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• 제6권1호
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• pp.51-59
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• 1972

$^{86}Rb$ uptake of some organs and tissues, ego both lungs, both renal cortices. small intestine, liver and skeletal muscle were studied in the control and the rabbit subjected to pneumothorax. $^{86}Rb$ in the form of chloride mixed with physiological saline was intravenously. injected. The doses were $100{\mu}c$ for a rabbit. The rabbits were sacrificed at intervals of 10, 20, 40, and 60 seconds after the injection of $^{86}Rb$, by the injection of saturated KCI solution. After sacrification, the organ and tissue sample were quickly removed. $^{86}Rb$ uptake in gm of the organs and tissues were measured. On the basis of uptake value, administered doses and body weight, % dose/gm tissues per 200 gm body weight was calculated. Followings were the results; 1. Pneumothorax resulted in a marked elevation in $^{86}Rb$ uptake value of collapsed lung and returned to normal level lately. 2. Contralateral lung of pnemothorax also showed marked elevation in $^{86}Rb$ uptake value and recovered to normal level. 3. Initial $^{86}Rb$ uptake value of liver, small intestine of the rabbit with pneumothorax showed some elevation as compared to control, but that of late stage were similar with control. 4. Local blood flow determination by means of $^{86}Rb$ uptake were inadequate in the collapsed lung of pneumothorax. 5. It was suggested that the mechanism for the initial elevation of $^{86}Rb$ uptake value in each organs and tissue were different from each other.

• Geomechanics and Engineering
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• 제11권1호
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• pp.161-175
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• 2016

A series of experimental studies are conducted on the deformation and shear strength property of compacted loess. The results reveal that the relationships of both the initial moisture content (w) and the initial degree of compaction (K) of compacted loess with cohesion (w) and the angle of internal friction (${\varphi}$) are linear. The relationship between the secant modulus ($E_{soi}$) and K is also linear. The relationship between $E_{soi}$ and w can be fitted well by a second-order polynomial. Further, when the influences of w and K are ignored, the relationship between the confined compression strain (${\varepsilon}$) and vertical pressure (p) can be expressed by a formula. A correction formula for the deformation of compacted loess caused by a change in w and K is derived on the basis of the study results.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.921-926
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• 2006

The present study has been conducted economic analysis through actual operation of EHP and GHP which are installed at the same building of an university Cost items, such as initial cost, annual energy cost and maintenance cost of each system are considered to analyze LCC and economical efficiency is compared. The initial cost is considered on the basis of actual costs, and annual energy cost is converted into the cost after measuring electricity and gas consumption a day. LCC applied present value method is used to assess economical efficiency of both them. Variables used to LCC analysis are electricity cost escalation rate, natural gas cost escalation rate, interest rate, and service lives and when each of them are 4%, 2%, 8%, and 20 years, results of analysis short that EHP(148,257,306 won) is 8.05%(12,981,990 won) more profitable than GHP(161,239,295 won).

• Nuclear Engineering and Technology
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• 제52권5호
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• pp.878-888
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• 2020

This paper presents the validation of UNIST in-house Monte Carlo code MCS used for the high-fidelity simulation of commercial pressurized water reactors (PWRs). Its focus is on the accurate, spatially detailed neutronic analyses of startup physics tests for the initial core of the Watts Bar Nuclear 1 reactor, which is a vital step in evaluating core phenomena in an operating nuclear power reactor. The MCS solutions for the Consortium for Advanced Simulation of Light Water Reactors (CASL) Virtual Environment for Reactor Applications (VERA) core physics benchmark progression problems 1 to 5 were verified with KENO-VI and Serpent 2 solutions for geometries ranging from a single-pin cell to a full core. MCS was also validated by comparing with results of reactor zero-power physics tests in a full-core simulation. MCS exhibits an excellent consistency against the measured data with a bias of ±3 pcm at the initial criticality whole-core problem. Furthermore, MCS solutions for rod worth are consistent with measured data, and reasonable agreement is obtained for the isothermal temperature coefficient and soluble boron worth. This favorable comparison with measured parameters exhibited by MCS continues to broaden its validation basis. These results provide confidence in MCS's capability in high-fidelity calculations for practical PWR cores.

• Asian-Australasian Journal of Animal Sciences
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• 제24권11호
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• pp.1560-1568
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• 2011

This study was conducted to evaluate the yield, nutrient characteristics, ruminal solubility, degradability and disappearance of spent mushroom (Agaricus bisporus) substrates for ruminants. The annual yield of spent Agaricus bisporus substrates was measured to be about 210,000 tons (M/T) in South Korea. The surface soil-removed spent substrates had nutritional characteristics of high crude ash (375 g/kg) and Ca (32 g/kg), medium protein (134 g/kg CP), and high fiber (384 g/kg NDF on a DM basis). Compared with initial mushroom substrates, spent mushroom substrates had twice higher (p<0.0001) CP content and 22.0% lower (p<0.0001) NDF content on an organic matter basis. Compared with raw rice straw, spent rice straw had much higher (p<0.05) predicted ruminal degradabilities and disappearances of DM and CP and a little lower (p<0.05) predicted degradability and disappearance of NDF. In conclusion, the general feed-nutritional value of spent mushroom (Agaricus bisporus) substrates appeared to improve after cultivation of mushrooms.

• Journal of Biosystems Engineering
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• 제5권1호
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• pp.15-23
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• 1980

Natural-air drying systems have been extensively used for cereal grains, and many researches on the systems have been conducted in foreign countries. However, little research on drying rough rice with natural air has been done. Especially . little research on natural air drying of rough rice based on weather data has been done in Korean. The objective of this study was to present fundamental data for estimating optimum requirements and basic information available for natural air drying of rough rice based on the weather data . The weather data analyzed in this study were the 10-year (1969 to 1978) record of air temperatures, wet-bulb temperatures and relative humidities, which were three-hourly observations in Taegu area. The results of this study are summarized as follows ; 1 From the results of weather data analysis the average air temperature was about $14.8^\circ$and the average relative humidty 67.5% . Average equilibrium moisture content appeared to be 13.8 percent on wet basis, which showed great potential for natural air drying in Taegue area in October. 2. Possible fan operation time based on the equilibrium moisture content of 15% on wet basis was about 14 hours a day during October in Taegu area. Probabilities of possible drying days based on minimum time available for drying in a day were analyzed. 3. Minimum air flow requirements based on the worst year were determined for different fan operation methods and initial moisture contents.

• 한국대기환경학회지
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• 제9권3호
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• pp.207-215
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• 1993

In order to statistically predict $O_3$ levels in Seoul, the study used the TMS (telemeted air monitoring system) data from the Department of Environment, which have monitored at 20 sites in 1989 and 1990. Each data in each site was characterized by 6 major criteria pollutants ($SO_2, TSP, CO, NO_2, THC, and O_3$) and 2 meteorological parameters, such as wind speed and wind direction. To select proper variables and to determine each pollutant's behavior, univariate statistical analyses were extensively studied in the beginning, and then various applied statistical techniques like cluster analysis, regression analysis, and expert system have been intensively examined. For the initial study of high level $O_3$ prediction, the raw data set in each site was separated into 2 group based on 60 ppb $O_3$ level. A hierarchical cluster analysis was applied to classify the group based on 60 ppb $O_3$ into small calsses. Each class in each site has its own pattern. Next, multiple regression for each class was repeatedly applied to determine an $O_3$ prediction submodel and to determine outliers in each class based on a certain level of standardized redisual. Thus, a prediction submodel for each homogeneous class could be obtained. The study was extended to model $O_3$ prediction for both on-time basis and 1-hr after basis. Finally, an expect system was used to build a unified classification rule based on examples of the homogenous classes for all of sites. Thus, a concept of high level $O_3$ prediction model was developed for one of $O_3$ alert systems.