• Korean Journal of Environmental Agriculture
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• v.14 no.3
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• pp.345-350
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• 1995

Another two different small composters with the double layer walls(Type 3 and Type 4) were made for dwelling house. One was insulated(Type 4) but the other uninsulated(Type 3). The change in microbial flora has been investigated through laboratory composting using these composters. The results were summarized as follows. 1. While the number of mesophilic bacteria decreased, that of thermophilic bacteria increased in winter. But thermophillic bacteria and mesophillic bacteria showed a tendency to increased in winter. But thermophilic bacteria and mesophillic bacteria showed a tendency to increase and decreas simultaneously in spring and summer at the early stage of composting. 2. The number of mesophilic actinomycetes ans thermophilic actinomycetes were decreased after I week in winter, while thermophilic actinomycetes rapidly increased in spring and mildly increased in summer. 3. The number of mesophilic fungi and thermophilic fungi had a tendency to increase and decrease simultaneously at an early stage of composting except after I week in winter. 4. Mesophilic bacteria, actinomycetes and fungi showed no difference in the number of microbes, but the number of fungi in spring was smaller than in other sensons. 5. At the late stage of composting process, the number of mesophilic fungi was decreased in winter and summer but increased in spring.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.22 no.3
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• pp.1-14
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• 2019

With a view to developing a database of death years of Korean firs (Abies koreana) at Yeongsil in Mt. Halla and investigating their abrupt inter-annual growth reduction tree-ring analysis was employed. To this end, 10 living trees (YSL) were selected to establish a master chronology and 20 dead trees were used to date their dead years. To investigate the difference in death years by death types, 10 trees, which remained standing (YSSD) out of the 20 dead trees were selected. The rest 10 dead trees were already fallen (YSFD). Two increment cores per tree at breast height were extracted in contour direction using an increment borer. A 106-year master chronology (1911-2016) was successfully established from the 10 YSLs. Through cross-dating between individual YSSD time series and the master chronology, it was verified that 1 YSSD was dead in summer 1978, 1 YSSD between autumn 1999 and spring 2000, 2 YSSDs in summer 2007, 1 YSSD in summer 2010, 1 YSSD in summer 2012, and 1 YSSD in summer 2013. The youngest tree rings of 2 YSSDs having no bark were in 1977 and 2002. For the YSFDs, it was verified that 1 YSFD was dead between autumn 1997 and spring 1998, 1 YSFD between autumn 2001 and spring 2002, 2 YSFDs between autumn 2009 and spring 2010, 1 YSFD in summer 2010, and 2 YSFDs between autumn 2012 and spring 2013, while the youngest tree rings of 2 YSFDs having no bark were in 1989 and 2004. To note, the death years of two trees, one from each death type (YSSD and YSFD), could not be verified due to poor cross-dating with the master chronology. The inter-annual growth reductions of YSSD and YSFD occurred more frequently and intensively than YSL. Typically, the YSFD showed the most frequent and intensive inter-annual growth reduction. On comparing the inter-annual growth reductions with the corresponding records of typhoons however we could not find any reliable relationship. Finally, from prior reports and results of the current study it can be concluded that the death and abrupt growth reduction of korean fir at Yeongsil in Mt. Halla are not caused by only a certain environmental factor but various factors.

• Journal of the Korean Solar Energy Society
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• v.27 no.2
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• pp.11-17
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• 2007

This study evaluates the seasonal performances of the horizontal-type geothermal heat exchanger(HGHEX) installed into the foundation slabs of the complex building located at Seoul. The geothermal system is consisted with totally 31,860m long HGHEX, 16 GSHPs (Ground-source Heat Pump) and 8 circulation pumps. This system supplies cooling and heating to the lobby(F1) and the common spaces(BF1). The average heat exchange temperature differences are $2.7^{\circ}C\;and\;2.5^{\circ}C$ in the summer, $1.5^{\circ}C\;and\;0.5^{\circ}C$ in the winter for the F1 and BF1 respectively. From these results, approximately 400Gcal and 180Gcal of geothermal energy are assumed to have been used during the summer and winter seasons respectively. As a conclusion, the geothermal system is reviewed as a effective utility for heating and cooling at the point of seasonal performances.

• Journal of Plant Biology
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• v.16 no.3_4
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• pp.17-34
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• 1973

The physico-chemical factors, the distribution of chlorophyll and the primary production of the lakes Hwajinpo, Yongrangho, Chunchonho, Uiamho, Soyangho and Changjamot have been studied in order to make ecological comparison among these lakes during summer stagnation period of August to September of 1973. On the basis of the characteristics of these lakes, the lake types have been discussed. Thermocline is observed at 3-4m zone in the lake Changjamot and 4-5m zone in the lake Yongrangho. In the case of lake Hwajinpo and impoundments, the distinct thermal stratification is not observed at the summer stagnation period. As to vertical distribution of dissolved oxygen, a positive heterograde curve is obtained in the lakes Hwajinpo and Yongrangho. In the lake Changjamot the typical clinograde curve and the oxygen depletion in hypolimnion are observed. In the case of impoundments, however, the orthograde curve is observed in the lakes Chunchonho and Uiamho. While in the lake Soyangho, any stratification of the disssolved oxygen is not found. In the brackish lakes, such as lakes Hwajinpo and Yongragho, the salinity of hypolimnion is found to be much higher than that of epilimnion. In the lake Hwajinpo, the salinity of hypolimnion is exhibited 32.7$\textperthousand$, which is nearly the same as sea water. The distribution of nitrogenous compounds and phosphates is found to be high in the lake Changjmot. The silicate is also found in high concentration in the lake Chunchonho, and the distribution of nutrients in the brackish lakes is generally low. As to the vertical distribution of chlorophyll level, the lake Changjamot shows a stratum type and the brackish lakes L-type stratification. In the impoundments, lakes Chunchonho and Uiamho appear to be homogeneous type. Seasonal variation of chlorophyll level in the lake Changjamot is examined from January to September 1973. The vertical distribution of chlorophyll during the period of circulation from January to April is homogeneous type and is stratum type thereafter. The maximum chlorophyll level is 277.4mg/$m^2$ on June 23 and the pattern of seasonal variation of chlorophyll level is comparable to the type of eutrophy. The horizontal distribution of chlorophyll level is studied in the brackish lakes, Hwajinpo and Yongrangho. The pattern of distribution is found to be an irregular type. On the basis of measurements of primary production by means of the carbon-14 method and the distribution of chlorophyll level, it is concluded that the interior part of the lake Hwajinpo and Changjamot are eutrophic and the exterior part of the lake Hwajinpo, lake Yongrangho and the impoundments, lake Uiambo and Soyangho are mesotrophic.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.10
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• pp.387-393
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• 2016

A ground source heat pump system maintains a constant efficiency due to its stable heat source and radiant heat temperature which provide a more effective thermal performance than that of the air source heat pump system. As an eco-friendly renewable energy source, it can reduce electric power and carbon dioxide. In this study, we analyzed one year of data from a web based remote monitoring system to estimate the thermal performance of GSHP with the capacity of 3RT, which is installed in a low energy house located in Daejeon, Korea. This GSHP system is a hybrid system connected to a solar hot water system. Cold and hot water stored in a buffer tank is supplied to six ceiling cassette type fan coil units and a floor panel heating system installed in each room. The results are as follows. First, the GSHP system was operated for ten minutes intermittently in summer in order to decrease the heat load caused by super-insulation. Second, the energy consumption in winter where the system was operated throughout the entire day was 7.5 times higher than that in summer. Moreover, the annual COP of the heating and cooling system was 4.1 in summer and 4.2 in winter, showing little difference. Third, the outlet temperature of the ground heat exchanger in winter decreased from $13^{\circ}C$ in November to $9^{\circ}C$ in February, while that in summer increased from $14^{\circ}C$ to $17^{\circ}C$ showing that the temperature change in winter is greater than that in summer.

• Journal of the Korean Institute of Landscape Architecture
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• v.31 no.3
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• pp.83-90
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• 2003

This study explored effects of urban greenspace on improving atmospheric environment, which is concerned with $CO_2$, SO$_2$ and NO$_2$ uptake, and with reduction of summer air temperatures. The site of this study was focused on Jung-gu in Seoul. Tree density and cover were 1.1 trees/100 $m^2$ and 12.5% respectively for the study area except forest lands. Atmospheric purification by greenspace was associated with changes in tree cover per unit area of each land use type. The mean $CO_2$ storage by woody plants was 19.4t/ha, and annual uptake averaged 2.2t/ha/yr for $CO_2$, 1.9kg/ha/yr for SO$_2$ and 5.0kg/ha/yr for NO$_2$. Entire tree plantings in the study area played a significant role by annually offsetting $CO_2$ emissions of about 1,830t from fossil fuel consumption by 330 persons, SO$_2$ emissions of 1,620kg by 1,080 persons, and NO$_2$ emissions of 4,230kg by 450 persons. The summer air temperature was 3.6$^{\circ}C$ cooler at a location with 54% cover of woody plants and 4.5$^{\circ}C$ cooler at a forest site with 100% cover, compared to a place with no planting. A 10% increase of woody plant cover was estimated to decrease summer air temperature by approximately 0.6$^{\circ}C$ until a certain level of canopy cover. Analyzing data from the Automatic Weather Stations in Seoul revealed that increasing tree cover decreased mean air temperature for the summer season (Jun~Aug) in a nonlinear function. Woody plant cover was the best predictive variable of summer temperature reduction. The results from this study are expected to be useful in emphasizing the environmental benefits and importance of urban greenspace enlargement, and in urging the necessity for planting and management budgets.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.3
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• pp.433-442
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• 2013

This study aimed to compare the dynamics of air temperature and velocity under two different ventilation and housing systems during summer and winter in Korea. The $NH_3$ concentration of both housing systems was also investigated in relation to the pig's growth. The ventilation systems used were; negative pressure type for the enclosed pig house (EPH) and natural airflow for the conventional pig house (CPH). Against a highly fluctuating outdoor temperature, the EPH was able to maintain a stable temperature at 24.8 to $29.1^{\circ}C$ during summer and 17.9 to $23.1^{\circ}C$ during winter whilst the CPH had a wider temperature variance during summer at 24.7 to $32.3^{\circ}C$. However, the temperature fluctuation of the CPH during winter was almost the same with that of EPH at 14.5 to $18.2^{\circ}C$. The NH3 levels in the CPH ranged from 9.31 to 16.9 mg/L during summer and 5.1 to 19.7 mg/L during winter whilst that of the EPH pig house was 7.9 to 16.1 mg/L and 3.7 to 9.6 mg/L during summer and winter, respectively. These values were less than the critical ammonia level for pigs with the EPH maintaining a lower level than the CPH in both winter and summer. The air velocity at pig nose level in the EPH during summer was 0.23 m/s, enough to provide comfort because of the unique design of the inlet feature. However, no air movement was observed in almost all the lower portions of the CPH during winter because of the absence of an inlet feature. There was a significant improvement in weight gain and feed intake of pigs reared in the EPH compared to the CPH (p<0.05). These findings proved that despite the difference in the housing systems, a stable indoor temperature was necessary to minimize the impact of an avoidable and highly fluctuating outdoor temperature. The EPH consistently maintained an effective indoor airspeed irrespective of season; however the CPH had defective and stagnant air at pig nose level during winter. Characteristics of airflow direction and pattern were consistent relative to housing system during both summer and winter but not of airspeed. The ideal air velocity measurement favored the EPH and therefore can be appropriate for the Korean environment. Further emphasis on its cost effectiveness will be the subject of future investigations.

• Proceedings of the Korean Society of Crop Science Conference
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• 1990.10a
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• pp.24-25
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• 1990

• Journal of environmental and Sanitary engineering
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• v.21 no.1 s.59
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• pp.66-75
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• 2006

When we looked at the seasonal food dregs of the eastern side of gangwondo, gangneung city's summer and winter food dregs showed 25.9 and 25.8% respectively due to the presence of beach areas and ski resorts. Sokcho city showed 28.12% in summer and yangyang gun's summer food dregs showed 40.2%. Yangyang gun's august food dregs showed 2.7 times larger than annual average amount. Outlook density showed regional characteristics. Data showed that food dregs' amount rate has been reduced gradually from 2005 because of the prohibition of direct filling up. As a result of compositions analysis, the eastern side of gangwondo's water fraction of living dregs were lower than that of chuncheon city where is located at the gangwondo's inland area. chuncheon city's data showed residential areas 53.5%, community areas 56.8% and commercial areas 55.6%. These discrepancies caused by the characteristics of dregs discharge type and climate. The caloric value of dregs has been increased incrementally after the ban of food dregs' direct filling up. Therefore, heating value of the dregs exceeds the existing furnace design spec and it can cause high caloric value problems, so we need additional research to solve these problems.

• Journal of the Korean Society of Costume
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• v.61 no.9
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• pp.97-113
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• 2011

To develop the work clothes for the employees in the mechatronics industry in South Korea, a questionnaire survey on many aspects of the work clothes such as type, color, detailed design and function preference of the subject employees has been carried out in the study. The results throughout the survey highlighted certain functions such as extensibility, thermal and air permeability of importance for the work clothing performance. To improve the discomfort caused by some work motions (i.e. squatting down, ascending/descending the stairs, raising arms), more allowances were given to the measurements (i.e. body rise + 2cm and crotch depth + 1cm for squatting down pose; thigh circumference + 1cm and knee circumference + 1cm for ascending/ descending the stairs pose; chest circumference + 5~6cm and jumper length to the level of hip circumference line for raising arms pose) for work clothes patternmaking. The evaluation of the two types of spring/summer and winter work clothes' clothing comfort and wearer mobility suggested certain points to improve the clothing performance (e.g. ventilation slits on the back pleats, arm pits and collar band of the spring/summer suit using net material and lining for the winter suit using quilted thermal materials) and wearer mobility (e.g. pants hem buckles for the easy work motion), which also enabled to fulfill the workers' work clothes design preference.