• Applied Microscopy
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• v.27 no.1
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• pp.47-56
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• 1997

The objective of the present study was to investigate the cytotoxicity of adriamycin in liver cells (group A), and the protective effect of squalene to the hepatocytes to which adriamycin-induced cytotcxicity (group B) was examined by transmission electron micro-scope. In the group A, The cisternae of rough endoplasmic reitculum and smooth endoplasmic reticulum are dilated/disoriented at 24 hours and 48 hours. The inner and outer membrane of mitochondria are detached or destructed , and attached ribosomes of rough endoplasmic reticulum are diminished in number. The cisternae of the smooth endoplasmic reticulum are dilated, and the cristae of mitochondria are disrupted at 72 hours and 96 hours. In the group B, the cisternae of the rough endoplasmic reticulum and smooth endoplasmic resticulum are dilated at 24 hours. The cisternae of the smooth endoplasmic reticulum are dilated at 48 hours. The cell organelles of hepatocytes are recovered from cytotoxicity at 72 hours. These results suggest that 50 is not only concerned with composition of the membrane system of the cell organelles but also decreased the cytotoxicity of the hepatocytes.

• Journal of Korean Port Research
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• v.10 no.1
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• pp.1-14
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• 1996

Rapid change in the technological environment of marine transportation and the development of the ocean shipping industry have fostered a revolution in the port system. This in turn has caused major changes in the function and use of port in Korea. Aside from this, Mokpo Port, however continues to decline, because the existing port facilities and related subsystem are already obsolete with no chance of regaining operational effectiveness and treatment for proper implementation. Although a few studies have been done on the Mokpo Port, has not been found, any reseach for the analytical approach to the transportation system of it. This paper aims to make an extensive analysis of the physical distribution system in Mokpo Port focusing on the coordination of subsystems such as navigational aids system. The base of introduced simulation tool here is the queueing theory. The overall findings are as follows: 1. Among those vessels called at Mokpo Port in 1994, 556 ships(2,736,669 G/T) are oceangoing while 8155 ships(2,587,217 G/T) are domestic. The average size of oceangoing vessels is 4,922,1 G/T, and the domestic is 317,8 G/T. The average arrival interval and service time of the domestic vessels are 6.0 hours and 24.1 hours respectively marking the berth occupation rate over 100%. Those for oceangoing vessels are 34.5 hours, 120.0 hours and 37.2%. In order to maintainin the berth occupation rate to 70% the capacity considering the 1994 of domestic piers must be extended to 145% and oceangoing vessels must be increased to 165%. 2. The capacity of approaching channel is enough to handle the total traffic volume of 3. Tugs are sufficiently being provided to handle all ships requiring their services 4. The capacity of storage and inland transportation systems are sufficient to handle the throughput and the yard stroage utilization rate of No.1 - No.5 is 4.5% and No.6 is 30% of 1993's. 5. The utilization rate of LLC(Level Looping Crane) and PNT(PNeumaTic) are 2.7% and 18.8%, respectively.

• Journal of Environmental Health Sciences
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• v.27 no.3
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• pp.11-20
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• 2001

An anaerobic sludge-aerobic fixed-bed biofilm(packed with ceramic support carrier of 1 inch size) reactor system was built up to treat textile wastewater. The efficiency of reactor system was examined by determining the effects of textile wastewater ratio(from 25% to 100% at HRT 24 h). The influent range of SCOD concentration and color were 1,036~1,357 mg/L, and 1,487~1,853 degree, respectively. When textile wastewater ratio was 100% and hydraulic retention time was 24 hours, SCOD removal efficiency by the anaerobic stage were 39.2% 100% and hydraulic retention time was 24 hours, SCOD removal efficiency by the anaerobic stage were 39.2% and the removal efficiency of the whole system were 75.8%. Color removal efficiency by the anaerobic stage were 45.4%(soluble color), and the removal efficiency of the whole system were 70.2%. In the A/A reactor system, the aerobic stage played an important role in removing both color and COD as well as anaerobic stage.

• Journal of Power System Engineering
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• v.21 no.3
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• pp.30-36
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• 2017

Carbon fiber shows excellent heat generation value and thermal efficiency comparing with the metallic materials because of its far infrared-rays and radiant heat. So, high performance and economic steam boiler system for the industry can be manufactured by using the carbon fiber heater. The far infrared ray radiation rate was more than 90 % of carbon fiber. Steam boiler system with carbon fiber heater in this study is made up of heating section. In the proof test of steam boiler, the aimed temperature and dwelling time were at $500^{\circ}C$ for 8,000 hours, $600^{\circ}C$-3,000 hours, and $700^{\circ}C$-1,000 hours. The temperature rise rate of steam boiler with carbon fiber heater was about 40% faster than that of the conventional boiler.

• Korean journal of food and cookery science
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• v.27 no.2
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• pp.61-71
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• 2011

This study was conducted to estimate the shelf-life of Kimbab manufactured using a Hazard Analysis and Critical Control Point (HACCP). We performed a microbiological verification after applying the HACCP plan to Kimbab. Additionally, the shelf-life of Kimbab at each holding temperature was calculated as a regression equation between the aerobic plate counts and holding time during the storage period. The critical control points of the HACCP plan, that were applied to Kimbab, included: cold-holding of refrigerated foods, checking the endpoint cooking temperature of heated food, and cold-holding of cooked foods. As a result of the microbiological verification of Kimbab, the aerobic plate counts averaged 3.46 log CFU/g. In contrast, the coliforms, E. coli, Staphylococcus aureus, and Salmonella spp. were not detected in any of the samples. The estimated shelf-life of Kimbab was calculated to be 45 hours at $10^{\circ}C$, 29 hours at $15^{\circ}C$, 6 hours at $25^{\circ}C$ and 3 hours at $35^{\circ}C$. In conclusion, manufacturers should apply a prerequisite program and a HACCP system for a safe consumption of ready-to-eat foods and label products with a proper shelf-life. Distributors should control the proper holding time-temperature until sale and consumers should eat immediately after purchasing ready-to-eat foods.

• The Journal of Internal Korean Medicine
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• v.30 no.3
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• pp.465-480
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• 2009

Objective : Lonicerae Flos has detoxifying properties and been used as antipyretic, antibacterial and antitumor. Fermentation of herbal medicine is known to increase the absorption, enhance effectiveness, decrease herbal toxicity and reduce side-effects. This study was performed to measure the effects of fermented Lonicerae Flos on influenza A/WSN (H1N1) virus replication. Material and Methods : Lonicerae Flos was fermented by Lactobacillus casei PM1. Fermented Lonicerae Flos was treated for 12 hours to MDCK (Mardin Darby canine kidney) cells, then cell-virulence was observed by MTT assay for 12 hours, 24 hours, and 36 hours after treatment. Following cases were conducted for 0, 10, 100, and $1000{\mu}g/ml$ concentrations of fermented Lonicerae Flos under the same time-frame; the fermented Lonicerae Flos was treated to MDCK cells before and after contamination by A-type influenza virus. The fermented Lonicerae Flos and the virus were mixed directly. The influence was observed by MTT assay and plaque assay. Results : These findings suggest that the fermented Lonicerae Flos inhibited the virulence of influenza A virus in MDCK cells and suppressed the plaque forming colonies induced by influenza A virus. Furthermore, pretreatment with fermented Lonicerae Flos was more effective than post-treatment. The titer of influenza virus was reduced for all before and after influenza A virus inoculation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.2
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• pp.305-314
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• 2017

Most of the existing researches on systemwide optimization of generator maintenance scheduling do not consider the equivalent operating hours(EOHs) mainly due to the difficulties of calculating the EOHs of the CCGTs in the large scale system. In order to estimate the EOHs not only the operating hours but also the number of start-up/shutdown during the planning period should be estimated, which requires the mathematical model to incorporate the economic dispatch model and unit commitment model. The model is inherently modelled as a large scale mixed-integer nonlinear programming problem and the computation time increases exponentially and intractable as the system size grows. To make the problem tractable, this paper proposes an EOH calculation based on demand grouping by K-means clustering algorithm. Network congestion is also considered in order to improve the accuracy of EOH calculation. This proposed method is applied to the actual Korean electricity market and compared to other existing methods.

• Journal of Electrical Engineering and Technology
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• v.11 no.2
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• pp.338-346
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• 2016

In order for the optimal solution of generators’ annual maintenance scheduling to be applicable to the actual power system it is crucial to incorporate the constraints related to the equivalent operation hours (EOHs) in the optimization model. However, most of the existing researches on the optimal maintenance scheduling are based on the assumption that the maintenances are to be performed periodically regardless of the operation hours. It is mainly because the computation time to calculate EOHs increases exponentially as the number of generators becomes larger. In this paper an efficient algorithm based on demand grouping method is proposed to calculate the approximate EOHs in an acceptable computation time. The method to calculate the approximate EOHs is incorporated into the optimization model for the maintenance scheduling with consideration on the EOHs of generators. The proposed method is successfully applied to the actual Korean power system and shows significant improvement when compared to the result of the maintenance scheduling algorithm without consideration on EOHs.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.04c
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• pp.75-79
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• 2008

In this paper, we measured the activation energy of the Bisphenol A type Epoxy resin (DGEBA)-Jeffamine system according to an irradiation. We put the mixed solutions to the silicon mold after mixing both DGEBA(216g) and Jeffamine(93.9g), curing agent of amine system. The mixed solutions were cured in the atmosphere during 24hours after finishing the first curing during 4hours in the vacuum oven under $80^{\circ}C$. The mixed solutions were cured in the atmosphere during 24hours after finishing the second curing during 12hours in the vacuum oven under $60^{\circ}C$ again. Prepared samples were irradiated to the dose rate of 8kGy/hr with 500kGy, 700kGy, 1000kGy, 1500kGy, 2000kGy, 2500kGy. Experimental results indicated activation energy of the samples reduced as the irradiation dose increased because of the peroxides of the Epoxy created by the oxidation and the radiation.

• Journal of Astronomy and Space Sciences
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• v.21 no.4
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• pp.505-528
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• 2004

We have reproduced the records of lunar occultation recorded in the History of Three Kingdoms(삼국사기), the History of the Koryo Dynasty (고려사), the Annals of the Choson Dynasty (朝鮮王朝實錄), the Daily Records of Royal Secretariat of the Choson Dynasty (승정원일기), and obtained the epochs of their realizations. We analysed these results to understand how the system of hours had been kept and when a day began. During most of the periods encompassed by these annals, the 12 double hours(12진각법) and the system of 100 divisions of the day (백각법) had been used when the lunar and the solar eclipses were calculated by royal astronomers. In these systems, the starting point of a day is midnight. On the other hand, the five watch system of hours (경점법), in which a night is divided into five watches, was also used. In this system, a day begins at the sunrise. We found that the traditional twilight, called dusk and dawn (혼명) and used in the east Asian countries, largely corresponds to the nautical twilight in modern concepts. This fact means that the Korean expressions and words for time system in every day life had originated form the five watch system of hours. We pointed out that the sunrise and sunset were convenient boundary lines to ancient astronomers, as well as to farmers in the agricultural society. Our results can be used to determine the exact epoch of each astronomical record in chronicles.