• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.452-455
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• 2007

The geothermal heat pump system is designed for cooling and heating for three stories building (2,435 $m^2$) includes total 79 heat pumps. Therefore, the monitoring system is installed for each floor and the data is automatically transmitted to the monitoring system. Heat exchange rate and temperature of a geothermal heat pump system have been monitored for a long period. The seasonal operation of geothermal heat pump shows the different shape of heat exchange rate for cooling and heating. Ground water flow can influence on heat exchange rate and thermal storage of the system. In order to define the hydraulic characteristics and groundwater temperature variation, the relationships among air temperatures, groundwater temperatures, water table, and precipitation are analysed.

• The Korean Journal of Ecology
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• v.6 no.2
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• pp.90-97
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• 1983

Seasonal changes of the soil nutrient contents and aboveground biomass, relationship between the soil nutrients and the productivity, and the net efficiencies of solar energy conversion were studied in two reeed communities (Phragmites communis Trin.) at the salt marsh in the estuary of the Sumjin-River from April 30 to October 9, 1981. The inorganic nutrients such as exchangeable sodium and potassium of soil were decreased during growing season. The amounts of organic matter, exchangeable sodium and potassium, total nitrogen, and available phosphorus in stand $\prod$ were much more than those of stand $\coprod$ . Productivity of Phragmites communis was positively correlated with the soil nutrients such as available phosphorus, exchangeable potassium and total nitrogen. The maximum dry matter productions of the aboveground parts in stand $\prod$ stand $\coprod$ were $ 1, 120g/m^2; and; 843g/m^2$ in August, and the net coversion efficiencies of PhAR based on growing season (April to September) were 1.77% and 1.33%, respectively.

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.239-241
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• 2010

Performance evaluation for an air conditioning system is conducted at a specified test conditions. One is low temperature and the other is high temperature condition. Most of the manufactures tried to improve the performance at higher outdoor temperature. One of the reasons is that the customer wants to get ore capacity at high temperature climate. To cope with these kinds of demand, manufactures are tried to achieve higher capacity at high temperature with minimum power consumption even with same size of the system. Consequently, previous studies on performance of the air conditioning system are focused on capacity and performance improvement at high outdoor temperature.

• Development and Reproduction
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• v.16 no.1
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• pp.1-8
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• 2012

The reproduction of animals is a way to maintain their species and demands a large amount of energy. The golden hamsters are seasonal breeders whose reproductive activities are regulated by photoperiod (length of day time in a day). The photic information received is transported to the pineal gland via many steps. Melatonin produced by the pineal gland affects the reproductive neuroendocrine system to manage reproductive activities. The major regulator neurons, secreting gonadotropin-releasing hormone, integrate all kinds of information to govern the reproductive frame hypothalamuspituitary-gonad axis. The elements impinging on the neurons are recently outspread. Thus the present review is to briefly survey the elements discovered newly and subjected to the active research realm and their correlations, focusing on the regulation of reproduction in mainly male golden hamsters as a representative animal.

• Korean Journal of Community Nutrition
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• v.12 no.1
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• pp.58-67
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• 2007

For the rapidly growing elderly population, the achievement and maintenance of good nutritional status is critical to health, functioning and quality of life. Elderly women living alone have been identified as a group associated with poor nutrition. The purpose of this study was to assess dietary intakes of elderly women living alone as compared to those of elderly women living with family in a rural area and to examine seasonal variation. The subjects are 49 elderly women living alone and 41 elderly women living with family who reside in Goryeong-gun, Gyeongbuk, and their food intakes were assessed once each time in summer 2005, winter 2005-2006, and spring 2006. The average ages were 74.7 years for living alone and 72.8 years for living with family. Education level was not different between the two groups. Height, weight, body mass index, systolic and diastolic blood pressures, and fasting blood glucose were not significantly different between the two groups. Average intakes of major nutrients, nutrient adequacy ratio, mean adequacy ratio and index of nutritional quality were lower in the elderly women living alone compared with the elderly women living with family in summer, but the differences in intakes of most nutrients became insignificant both in winter and in spring. High carbohydrate and low fat diet was prevalent and intakes of carbohydrate and fat in summer deviated from macronutrient acceptable distribution ranges. Percentages of the subjects who consumed energy less than 75% of the estimated energy requirement and nutrients less than the estimated average requirement were higher than those reported by the Third National Health and Nutrition Examination Survey. In summer, the percentage of the subjects who consumed energy less than both 75% of the estimated energy requirement and 4 nutrients less than estimated average requirements was 58.5% of the elderly women living alone, which was higher than 26.5% of the elderly women living with family and that of National Nutrition Survey. Therefore, nutrition policies including nutrition education and support are necessary to improve nutritional status of elderly, especially elderly women living alone and should reflect regional and seasonal characteristics.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.2
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• pp.109-119
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• 2012

Long-term wave observation was carried out near Busan New Port and the major wave characteristics were analyzed. At Busan New Port, waves from south direction were predominant throughout the year, while waves from the west, developed at the north sea of Geoje island, appeared almost the same frequency in winter season, showing apparent seasonal variation. During the observation period, the significant wave height was mostly less than 1 m, but it reached its maximum of 8.0 m when typhoon Maemi passed on September 2003. Also, the seasonal variation was hardly observed except July. In contrast, seasonal variation was apparent for the significant wave period, whose peak ranges 4~5 s in summer whereas about 3 s in winter. The largest significant wave period was 15.56 s, observed on June 2003. Meanwhile, the annual variation was negligible for mean wave direction as well as significant wave height and period. Further analysis of the wave data acquired for 5 years at 4.5 km south, in the south sea of Daejuk island, confirmed high correlation between the two observation points in summer and vice versa in winter.

• Journal of the Korean Institute of Gas
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• v.23 no.2
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• pp.74-81
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• 2019

Expansion turbine system to recover the electricity energy from natural gas transmission stations is a well-known technique. The turbo-expander efficiency depends on the ratio of the natural gas flow rates to the design flow rate of the turbo-expander. However, if there is a big difference of the natural gas flow rate through the pressure letdown station because of seasonal supply pattern, that is, high flow rate in winter while low flow rate in summer, single turbo-expander system is not so efficient as to recover the pressurized energy from the low flow-rate natural gas. Therefore, we have proposed a new concept of double turbo-expander system: one is a big capacity and the other a small capacity. Here we have theoretically computed the electric powers at the pressure reduction from 18.5 bar to 7.5 bar depending on the inlet conditions of temperature and flow rate. The calculated electricity generation has been increased by 30% from 12.4 MW in a single turbo expander to 16.1 MW in the proposed double turbo-expander system when a minimal design efficiency of 0.72 is applied.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.2
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• pp.151-163
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• 1992

Seasonal variations of water mass distributions in the Yellow Sea, the East China Sea, and the adjecent seas of Cehju Island, are investigated. A common seasonal variation over these whole areas is shown. Warm and saline waters are extended northwestward into the Yellow Sea in winter and retreated back southeastward to the East China Sea in summer. Barotropic numerical model results suggest that monsoon winds could drive such seasonal variations. Upwind flows play an important role in the processes. In the numerical model results, upwind flows are shifted to China. It is due to energy dissipations by complicated coast lines and shallow bottom topographies in the northern part of the Yellow Sea. The shifted routes of upwind flows agrees well with that of the southward extensions of the Yellow sea Bottom Cold Waters in summer.

• Journal of Korean Society for Atmospheric Environment
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• v.32 no.2
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• pp.208-215
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• 2016

Pinic acid (PA) and cis-pinonic acid (CPA) in the atmospheric particulate matter with an aerodynamic diameter of less than or equal to a nominal $10{\mu}m$ ($PM_{10}$) were analyzed for the samples collected during the period of April 2010 to April 2011 at Jongro in Seoul. Both pinic acid and cis-pinonic acid showed higher seasonal average concentrations in summer (PA; $18.9ng/m^3$, CPA; $16.0ng/m^3$) than winter (PA; $5.3ng/m^3$, CPA; $5.9ng/m^3$). They displayed a seasonal pattern associated with temperature reflecting the influence on emissions of ${\alpha}-pinene$ and ${\beta}-pinene$ from conifers and their photochemical reaction. These results were confirmed through Pearson correlation coefficient between CPA, PA and $O_3+NO_2$, temperature. CPA was only correlated with n-alkanes ($C_{29}$, $C_{31}$, $C_{33}$) from biogenic source. PA was correlated with n-alkanes ($C_{29}$, $C_{31}$, $C_{33}$), n-alkanoic acid ($C_{20}$, $C_{22}$, $C_{24}$) from biogenic source and n-alkanes ($C_{28}$, $C_{30}$, $C_{32}$), and n-alkanoic acid ($C_{16}$, $C_{18}$) from anthropogenic source. These results showed that the formation of PA and CPA from ${\alpha}-pinene$ and ${\beta}-pinene$ is related to organic compounds from biogenic source. And it is possible for PA to be effected by organic compounds from anthropogenic source.

• Proceedings of the KIEE Conference
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• 2007.11b
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• pp.255-257
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• 2007

Korea electricity market consists of two payment systems, capacity and energy. Capacity payments are given to the generators according to its hourly availability considering hourly and seasonal weighting factors. Energy payments are settled at the marginal generation cost based on generator variable cost. In 2007, base load energy market is closed and single capacity payment system is begun to apply in electricity market. In this revised market rule, energy price cap for base load generators is newly introduced. We analyze impact of market rule revision in 2007 on base load generators and suggest improvement scheme to enforce market system in this study.