• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.12
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• pp.715-732
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• 2009

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2008. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) Research trends in thermal and fluid engineering have been surveyed in the categories of general fluid flow, fluid machinery and piping, new and renewable energy, and fire. Well-developed CFD technologies were widely applied in developing facilities and their systems. New research topics include fire, fuel cell, and solar energy. Research was mainly focused on flow distribution and optimization in the fields of fluid machinery and piping. Topics related to the development of fans and compressors had been popular, but were no longer investigated widely. Research papers on micro heat exchangers using nanofluids and micro pumps were also not presented during this period. There were some studies on thermal reliability and performance in the fields of new and renewable energy. Numerical simulations of smoke ventilation and the spread of fire were the main topics in the field of fire. (2) Research works on heat transfer presented in 2008 have been reviewed in the categories of heat transfer characteristics, industrial heat exchangers, and ground heat exchangers. Research on heat transfer characteristics included thermal transport in cryogenic vessels, dish solar collectors, radiative thermal reflectors, variable conductance heat pipes, and flow condensation and evaporation of refrigerants. In the area of industrial heat exchangers, examined are research on micro-channel plate heat exchangers, liquid cooled cold plates, fin-tube heat exchangers, and frost behavior of heat exchanger fins. Measurements on ground thermal conductivity and on the thermal diffusion characteristics of ground heat exchangers were reported. (3) In the field of refrigeration, many studies were presented on simultaneous heating and cooling heat pump systems. Switching between various operation modes and optimizing the refrigerant charge were considered in this research. Studies of heat pump systems using unutilized energy sources such as sewage water and river water were reported. Evaporative cooling was studied both theoretically and experimentally as a potential alternative to the conventional methods. (4) Research papers on building facilities have been reviewed and divided into studies on heat and cold sources, air conditioning and air cleaning, ventilation, automatic control of heat sources with piping systems, and sound reduction in hydraulic turbine dynamo rooms. In particular, considered were efficient and effective uses of energy resulting in reduced environmental pollution and operating costs. (5) In the field of building environments, many studies focused on health and comfort. Ventilation. system performance was considered to be important in improving indoor air conditions. Due to high oil prices, various tests were planned to examine building energy consumption and to cut life cycle costs.

• Korean journal of communication and information
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• v.46
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• pp.511-555
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• 2009

Media-related regulations can be classified into two categories; regulations of individual media contents and regulations regarding the entry to and withdrawal from a certain field. In this dissertation, ownership regulations are regarded as legal and political measures so as to prevent the monopoly and oligopoly of public opinion, and to secure its diversity. Every country has its own regulation model according to its particular media environment. Korea too is obliged to actively respond to its environmental changes, at the same time vitalizing the media industry and protecting consumers' rights and interests. Strong political intentions to protect the public interest is necessary when it comes to media regulation policies, especially in the circumstances that public interest is an industrial priority. As the convergence of broadcasting and telecommunications is leading to a major shift in the media industry, the regulation of cross-media ownership is an issue involving potential conflicts among media-owners, non-governmental organizations and the authorities concerned, depending on their various viewpoints regarding the media industry. In this paper, an attempt was made to search necessity of redefining 'public interest', which is the logic behind the restriction of cross-media ownership, and to reconceptualize issues on the centralization and diversity of media. First, an examination of the actual conditions of newspaper companies was carried out in order to reinvestigate domestic cross-media ownership issues, which is represented by the cross-ownership issue of newspapers and broadcasting stations. Next, the dilemma of policies stimulated by the fusion of media was discussed based on cross-media ownership restrictions, and the need for efficient conflict control was suggested. Finally, proposals on the independency and public confidence of media-related policy-making authorities, the rationalization of regulation models, an itemized discussion on cross-media ownership regulation issues, the elaboration of measures for a balanced development among media were made. It could be found that a number of foreign countries were still facing challenges to prevent monopoly and oligopoly of the public opinion and the industry. A solution to settle disagreements about the dilemma of the media industry, including the cross-media ownership regulation issues, must be arranged on the grounds of 'mutual respect of public interest and industrial interest', In Korea, an ease on the ownership regulations adapting to the change in the media industry may be considered, however the softening of the cross-media ownership regulations must be approached with the utmost care. Paradoxically Relieving cross-media ownership regulations may be considered the foundation of a richer field of journalism, where there is no need for concern over the monopoly and oligopoly of public opinion.

• Journal of Forest and Environmental Science
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• v.10 no.1
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• pp.57-65
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• 1994

This study was carried out to clarify the sediment export by measuring suspended solids included in streamflow during the rainy season. The study area is located in Experimental Forests, Kangwon National University, where the forest road is under construction. For this purpose, the forest watershed with construction of forest road was compared with normal forest watershed in amount of rainfall and discharge, suspended solids and discharge, and the amount of rainfall and suspended solids. The results were shown as followings. 1. The relationship of discharge and the amount of rainfall was shown as Table 3 and Fig. 3. The delay time of peak point observed in hydrograph was changed by rainfall intensity and amount of previous rainfall. That is, when there was a rain on 12. Jun(more than 20mm/hour for hours), the peak point began three hours after the rainfall intensity over 20mm/hour, and showed $1514m^3/hour$ in automatic water level recorder. In case of the 8th of Aug.(maximum rainfall intensity: 40mm/hour), the peak point of discharge was $1246m^3/hour$ in the same time with maximum rainfall intensity. And on the 20th of Aug.(the maximum rainfall intensity: 17.2mm/hour), the peak point of discharge was $1245m^3/hour$ two hours after the maximum rainfall intensity. 2. On watershed under forest road construction, the relationship between discharge and suspended solids is that suspended solids was proportionately increased by raising discharge. That is, on the 12th of Jun, the maximum of discharge per hour was $1514m^3/hour$ and 1261mg/l of suspended solids was observed an hour after peak point of discharge. And in case of 8th and 20th Aug., each of peak points is $1246m^3/hour$ and $1245m^3/hour$ by measuring time. The maximums of suspended solids measured within two watersheds were examined in value of 4952mg/l and 472mg/l at the same time. 3. During the rainy season, the concentration of suspended solids was influenced by rainfall intensity and indicated especially curve-regressional increase in case of strong rainfall intensity. In each of watersheds, the maximums of suspended solids were 1261mg/l and 125mg/l, 4952mg/l and 44mg/l, and 472mg/l and 4mg/l by the order of rain(a), (b), and (c). Two watersheds showed a remarkable difference.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.7
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• pp.959-967
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• 2005

Lead is a ubiquitous environmental and industrial pollutant that causes a major health concerns. It is known to induce a broad range of physiological, biochemical, and behavioral dysfunctions in laboratory and humans, including hematopoietic system, kidneys, liver, and reproductive system. This study was conducted to investigate the effect of Saengshik supplementation on the lead-induced toxicity in rats. Five week old male Sprague­Dawley rats were randomly assigned to five groups for six weeks as followings: control group (CT), lead acetate treated group (PT), and lead acetate groups administered with three different dosages of Saengshik $(SI2.5-12.5\%,\;S25-25\%,\;and\;S50-50\%).$ Lead acetate (12 mg/rat) was intragastrically administered daily for 6 weeks. The results were summarized as follows; Weight gain and food efficiency ratio were significantly lower (p<0.05) in lead administered group compared with those of the control group. Also, significant lead-induced alteration in blood hemoglobin (HGB), hematocrit (HCT), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and reticulocyte distribution width (RDW) were observed. In the liver of lead-exposed animals, there was an increase in the lipid peroxidation (MDA) and the level of glutathione (GSH), but superoxiede dismutase (SOD) activity did not change. Lead-exposed animals with $25\%\;and\;50\%$ Saengshik supplementation showed marked improvements in the values of MCH, MCV, and RDW. Also, the level of HCT was significantly increased by $50\%$ Saengshik supplementation. The levels of liver MDA in $12.5\%\;and\;50\%$ Saengshik administered groups and GSH level in $50\%$ Saengshik administered group were significantly decreased compared to the lead administered group. Also, hepatic SOD activity tended to increase in the presence of Saengshik supplementation. Furthermore, the accumulation of lead in liver and kidney was reduced by presence of Saneghshik supplementation. Liver lead concentration was significantly reduced by both $25\%\;and\;50\%$ Saengshik supplementations and kidney lead concentration was significantly reduced by the $25\%$ Saengshik supplementation. These results show that Saengshik may have a protective effect against lead intoxication but the mechanism of their effects remains unclear.

• Journal of Korean Society of Forest Science
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• v.94 no.6
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• pp.370-376
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• 2005

Sarcodon aspratus is well known as a natural edible mushroom and a symbiotic mycorrhizal fungus with oaks. This study was conducted to clarify the effects of environmental conditions on the fruiting of S. aspratus on the hillslope of Wolak Mt., Jecheon city, Chungbuk, South Korea. Soil moisture and soil temperature in S. aspratus colony were measured hourly and compared with those in the non-colony soil. The mean soil moisture during the mushroom development was 14.3% in the colony soil and 16.4% in the non-colony soil. The S. aspratus colony soils showed 2.1% less soil moisture. The mean soil temperature was $16.8^{\circ}C$ in the colony soil and $16.5^{\circ}C$ in the non-colony soil. The S. asprauts colony soils showed slightly higher temperature. It is considered that more soil water was consumed and more energy was emitted during the mycelial elongation and the mushroom development. The development of S. aspratus seems similar to that of T. matsutake which is known to be considerably affected by soil moisture, daily maximum air temperature, daily minimum air temperature and daily minimum soil temperature. The season of S. aspratus development ranges from the end of August to the beginning of October. And Ellino phenomenon and its unusual change in the weather seems to affect primodia and fruiting body development. Especially if daily minimum soil temperature continues to become higher than $20^{\circ}C$, the damage of primodia and its fruiting body was frequently observed in the field plots during the last few years recently.

• Clean Technology
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• v.21 no.1
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• pp.76-82
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• 2015

Volatile organic compounds (VOC) free adhesives have been interested by many scientists and engineers due to environmental regulations and the safety of industrial workers. In this work, a series of composites composed with bisphenol A epoxy resin used as solvent, dicyandiamide, and promoter were prepared to investigate the most appropriate molar ratio for steel-steel adhesion. The cured test specimen of each composite were measured with universal testing machine (UTM) to figure out mechanical properties such as tensile strength, Young’s modulus, and elongation. Furthermore, the lap shear strength of the specimen was tested with UTM while impact resistance was measured with Izod impact tester. The composite whose molar ratio of epoxy resin to curing agent is 1 : 0.9 (sample 3), showed better tensile strength, coefficient of elastic modulus, elongation, and impact strength than other composites did. The highest tanδ from dynamic mechanical analysis (DMA) was observed from sample 2 (epoxy resin: dicy = 1 : 0.7) while sample 3 showed slightly lower tanδ than that of 2. The morphology of the fracture surface of the cured composites from SEM showed that the number of subtle lines on the surface caused by impact increase as the contents of amine curing agent accrete. Furthermore, the viscosity change of sample 5 (epoxy resin: dicy = 1 : 1.3) was observed to confirm its storage stability.

• Journal of Bio-Environment Control
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• v.24 no.2
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• pp.100-105
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• 2015

The calculation method of infiltration loss in greenhouse has different ideas in each design standard, so there is a big difference in each method according to the size of greenhouses, it is necessary to establish a more accurate method that can be applied to the domestic. In order to provide basic data for the formulation of the calculation method of greenhouse heating load, we measured the infiltration rates using the tracer gas method in plastic greenhouses equipped with various thermal curtains. And then the calculation methods of infiltration loss in greenhouses were reviewed. Infiltration rates of the multi-span and single-span greenhouses were measured in the range of $0.042{\sim}0.245h^{-1}$ and $0.056{\sim}0.336h^{-1}$ respectively, single-span greenhouses appeared to be slightly larger. Infiltration rate of the greenhouse has been shown to significantly decrease depending on the number of thermal curtain layers without separation of single-span and multi-span. As the temperature differences between indoor and outdoor increase, the infiltration rates tended to increase. In the range of low wind speed during the experiments, changes of infiltration rate according to the outdoor wind speed could not find a consistent trend. Infiltration rates for the greenhouse heating design need to present the values at the appropriate temperature difference between indoor and outdoor. The change in the infiltration rate according to the wind speed does not need to be considered because the maximum heating load is calculated at a low wind speed range. However the correction factors to increase slightly the maximum heating load including the overall heat transfer coefficient should be applied at the strong wind regions. After reviewing the calculation method of infiltration loss, a method of using the infiltration heat transfer coefficient and the greenhouse covering area was found to have a problem, a method of using the infiltration rate and the greenhouse volume was determined to be reasonable.

• Journal of Bio-Environment Control
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• v.25 no.3
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• pp.218-223
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• 2016

The calculation method of ground heat exchange in greenhouses has different ideas in each design standard, so there is a big difference in each method according to the size of greenhouses, it is necessary to establish a more accurate method that can be applied to the domestic. In order to provide basic data for the formulation of the calculation method of greenhouse heating load, we measured the soil temperature distribution and the soil heat flux in three plastic greenhouses of different size and location during the heating period. And then the calculation methods of ground heat exchange in greenhouses were reviewed. The soil temperature distributions measured in the heating greenhouse were compared with the indoor air temperature, the results showed that soil temperatures were higher than room temperature in the central part of greenhouse, and soil temperatures were lower than room temperature in the side edge of greenhouse. Therefore, it is determined that the ground heat gain in the central part of greenhouse and the perimeter heat loss in the side edge of greenhouse are occurred, there is a difference depending on the size of greenhouse. Introducing the concept of heat loss through the perimeter of building and modified to reflect the size of greenhouse, the calculation method of ground heat exchange in greenhouses is considered appropriate. It was confirmed that the floor heat loss measured by using soil heat flux sensors increased linearly in proportion to the temperature difference between indoor and outdoor. We derived the reference temperature difference which change the direction of ground heat flow and the perimeter heat loss factor from the measured heat flux results. In the heating design of domestic greenhouses, reference temperature differences are proposed to apply $12.5{\sim}15^{\circ}C$ in small greenhouses and around $10^{\circ}C$ in large greenhouses. Perimeter heat loss factors are proposed to apply $2.5{\sim}5.0W{\cdot}m^{-1}{\cdot}K^{-1}$ in small greenhouses and $7.5{\sim}10W{\cdot}m^{-1}{\cdot}K^{-1}$ in large greenhouses as design standard data.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.1
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• pp.9-17
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• 2017

Characteristics of aerodynamic damping ratios of a helical $180^{\circ}$ model which shows better aerodynamic behavior in both along-wind and across-wind responses on a super tall building was investigated by an aeroelastic model test. The aerodynamic damping ratio was evaluated from the wind-induced responses of the model by using Random Decrement (RD) technique. Further, various triggering levels in evaluation of aerodynamic damping ratios using RD technique were also examined. As a result, it was found that when at least 2000 segments were used for evaluating aerodynamic damping ratio for ensemble averaging, the aerodynamic damping ratio can be obtained more consistently with lower irregular fluctuations. This is good agreement with those of previous studies. Another notable observation was that for square and helical $180^{\circ}$ models, the aerodynamic damping ratios in along-wind direction showed similar linear trends with reduced wind speeds regarding of building shapes. On the other hand, for the helical $180^{\circ}$ model, the aerodynamic damping ratio in across-wind direction showed quite different trends with those of the square model. In addition, the aerodynamic damping ratios of the helical $180^{\circ}$ model showed very similar trends with respect to the change of wind direction, and showed gradually increasing trends having small fluctuations with reduced wind speeds. Another observation was that in definition of triggering levels in RD technique on aerodynamic damping ratios, it may be possible to adopt the triggering levels of "standard deviation" or "${\sqrt{2}}$ times of the standard deviation" of the response time history if RD functions have a large number of triggering points. Further, these triggering levels may result in similar values and distributions with reduced wind speeds and either may be acceptable.

• The Korean Journal of Malacology
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• v.32 no.4
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• pp.263-268
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• 2016

Metallothionein (MT) family of metal-binding proteins are involved in maintaining homeostasis and heavy metal poisoning. Recently, MT has been considered as a biomarker that can identify a particular species, very similar to the use of cytochrome oxidase I (COI) gene. Satsuma myomphala species of land snails have been reported from North-East Asia, including South Korea and Japan. In particular, the land snail species have been known from only a limited area of Geoje Island, Gyeongsangnam-do province of South Korea. Genetic studies of S. myomphala has been limited with only 6 nucleotide, 2 protein registered on the NCBI server. For elucidating the genetic information of S. myomphala, we conducted RNA sequencing analysis using Illumina HiSeq 2500 next-generation platform. We screened the MT gene from the RNA-Seq database to confirm the molecular phylogenetic relationship. After sequencing, the de novo analysis and clustering generated 103,774 unigenes. After annotation against PANM database using BLAST program, we obtained MT sequence of 74 amino acid residues containing the coding region of 222 bp. Based on this sequence, we found about 53 sequences using the BLAST program in NCBI nr database. Using ClustalX alignment, Maximum-Likehood Tree of MEGA program, we confirmed the molecular phylogenetic relationships that showed similarity with mollusks such as Helix pomatia and H. aspersa, Megathura crenulata.