• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.174-178
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• 2006

This study was conducted to compare the changes of isoflavone content grown at different planting dates and to determine a relationship between growing periods and isoflavone content, in soybean. A total fifty six soybean varieties, including summer type soybean, Chinese varieties and domestic soybean varieties, were used this experiment. Mean total isoflavone content of domestic soybean varieties was higher than summer type soybean varieties and Chinese varieties. And, the soybean isoflavone content was significantly increased in growth at late planting dates. Soybean isoflavone contents was increased with longer reproductive growth period. While, the relationship between seed weight and isoflavone content showed significantly negative correlation coefficient, -0.57 at Apr. 15, -0.51 at May 15, and -0.38 at Jun. 15, respectively planting dates.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.2
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• pp.230-236
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• 2009

In this paper, in order to utilize new and renewable energy a grid-connected parasol-type solar power generation system is presented. The proposed power system combining with commercial electric power system is designed to meet the need fur maximum power consumption and parasols for the people staying at beach during hot summer. Solar electric power can be charged in rechargeable batteries during day time and used to provide charged electric power to loads like lamps and fans during night time, A battery charge-discharge controller is required for the good performance of batteries to be charged. The presented battery controller is designed based on high performance microprocessor for precise charge-discharge operations. An alarm circuit to give notice of battery exchange time and other convenient functions are installed in the system. We implemented the proposed solar power generation system at East Sea beach during peak summer season to verify its productivity and performance by experiments.

• Journal of Ecology and Environment
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• v.38 no.3
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• pp.375-381
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• 2015

We investigated the influence of summer rainfall on Pectinatella magnifica colonies in lotic ecosystems. Of the examined substrate materials, branches and aquatic macrophytes supported more colonies of P. magnifica than that by stones or artificial materials. The influence of rainfall on P. magnifica colonies differed in accordance with the type of substrate material at each study site. In the Geum River, little difference was noted in the number of P. magnifica colonies on branches before ($mean{\pm}SE$, $24{\pm}7.3$ individuals) and after rainfall ($20{\pm}8.4$ ind.); other substrate types supported fewer colonies of P. magnifica after rainfall. In contrast, in the Miryang River, rainfall had minimal effect on the number of P. magnifica colonies supported by macrophytes ($13{\pm}3.8$ and $12{\pm}4.3$ ind., respectively). Artificial material was more abundant in the Banbyeon Stream where it was able to support more colonies of P. magnifica. We found that the structure of different substrates sustains P. magnifica following rainfall. In the Miryang River, free-floating and submerged plants with a relatively heterogeneous substrate surface were the dominant macrophytes, whereas in the Geum River, simple macrophytes (i.e., emergent plants) were dominant. Therefore, we conclude that the substrate type on which P. magnifica grows plays an important role in resisting physical disturbances such as rainfall.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.1
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• pp.50-54
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• 1984

To study the effects of planting dates and mulching on the growth and yield of summer type soybean, a variety, Damamidori introduced from Japan, was planted four times from April 13 with 10 days interval. Experimental plot in each planting date was devided into two sub-plots, polyethylene film mulching and non-mulching. By mulching, days to emergence and first flowering were shortened, especially in the early plantings; e.g. as much as 11 and 12 days, respectively, in the first planting. Compared to non-mulching, plant height, number of nodes of main stem, number of branches, and dry weight of stem and branches per unit area were also much increased by mulching. As the plantings were delayed, plant height, the total number of nodes and dry weight of main stem and branches, and 100 seed weight showed increasing trends, which were mainly due to lower infection rate of soybean seeds to pod and stem blight (Diaporthe phaseolorum) in the later plantings. The higher infection rate of soybean seeds to pod and stem blight, the lower infection rate to purple seed stain (Cercospora kikuchii) was shown in mulching but not in non-mulching.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.27 no.3
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• pp.170-177
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• 1991

This paper presents the seasonal variation of distribution and flushing time of the fresh water in Suyoung Bay based on the monthly observation from May 1989 through April 1990 and Pusan City Report of Suyoung Bay. Most of Suyoung river water was trapped inside of the bay west of the Dong-Baek Island located. Low salinity water lies dominantly on the right hand side of the Suyong river. Salinity structure of the bay is the well mixed type in summer and the partially mixed type in other season. The fresh water fraction varied in an exponetial manner from unity at the head of bay toward a value of zero at the its mouth. The calculated average flushing time during a year was about 10-15days. About 1.5 days was in summer because the strong fresh water discharge from the river was dominated in the bay.

• Journal of fish pathology
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• v.4 no.1
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• pp.15-21
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• 1991

The environmental factors and the distribution of coliform group were investigated in Suyeong bay on the summer, 1989. The ranges of environmental factors were as follows : Dissolved oxygen $0.54{\sim}6.82m{\ell}/{\ell}$, COD(Chemical Oxygen Demand) 0.28~9.84ppm, Salinity 14.7~33.5%, Nitrite $0.13{\sim}20.49{\mu}g-at/{\ell}$, Nitrate $0.89{\sim}62.77{\mu}g-at/{\ell}$, Ammonia $3.81{\sim}246.98{\mu}g-at/{\ell}$, Silicate $6.12{\sim}177.5{\mu}g-at/{\ell}$. The coliform group ranged $10^4{\sim}10^5/100m\ell$ in the mouth and it was decreased in the open sea. Among the composition of coliform group, E. coli I type was dominent at distance area. The correlation between coliform group and ammonia was r=0.629. There were negative correlation between salinity, dissolved oxygen and coliform group during study period.

• Animal cells and systems
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• v.1 no.1
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• pp.99-105
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• 1997

Using three species of Korean frogs (Rana dybowskii, R. rugosa and R. nigromaculata), the annual spermatogenic pattern, the seasonal changes in the steroidogenic competence, and responsiveness of testis to gonadotropins in terms of testosterone secretion in vitro were examined. The spermatogenic pattern of R. dybowskii was classified as a discontinuous type since spermatogenesis stops completely after spawning in late winter (February) until mid-summer (July). In contrast, the pattern of R. nigromaculata and R. rugosa was classified as a potent continuous type since sperm was always present in the seminiferous tubules all year round. In all three species, the levels of testicular testosterone and that of testosterone secreted by testis following in vitro culture were very low in late summer (August), but increased thereafter until winter (hibernation period). Interestingly, responsiveness of testis in vitro to gonadotropins in terms of testosterone secretion increased markedly in November (early hibernation period). Specifically, bullfrog LH was more effective than FSH in stimulating the secretion of testosterone by frog testis in vitro during hibernation period. This fact suggests that testosterone secretion by testis during hibernation is at least regulated by the pituitary gonadotropin rather than environmental factors. Taken together, the data presented here suggest that testicular cycles of three species of Korean frogs are closely linked to their females breeding cycles, and are eventually controlled by various environmental cues.

• Korean Journal of Environment and Ecology
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• v.24 no.1
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• pp.46-53
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• 2010

The purpose of this study is to provide a database for the reduction of road-kills in the Odaesan National Park. To accomplish this task, investigations were conducted on the road-kills that occurred in the period from 2003 to 2007. The results of investigations are as follows: 427 road-kill cases were reported during the period, and the road-kill victims turned out to be mostly small mammals. Among mammals and reptiles the road-kill occurrence rate of squirrels and garters was higher than that of other species, and in the case of birds, the road-kill occurrence rate of yellow-throated bunting was the highest. The road-kill accidents of mammals and reptiles took place more frequently during the summer and autumn, while those of birds during the spring and summer. The increase of road-kill occurrence rate was found to be related to the activity and breeding period of wild animals, as well as to the increase of vehicles. The occurrence rate of road-kills was also found to be influenced by the type of land use on the roadside. Furthermore, the occurrence rate increased significantly when the roads passed through dry fields.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.387-392
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• 2006

The recent on indoor air problem has led to many studies on the methods and effects of ventilation for better indoor air quality. Although natural ventilation is the most effective and energy-saving method in residental housings, the small size of openable window has been a problem in high-rise residential buildings to ventilate only through natural ventilation. Consequently, the installation of mechanical ventilation system has been a requirement in residential buildings, and has caused other problems such as increase of energy consumption and SBS. Hybrid ventilation which uses forces of both natural and mechanical power has been introduced to solve the problem of increase in energy consumption with natural ventilation. In this paper, two types of hybrid ventilation systems in residential building were introduced. One type was with natural ventilation through vent grille in the window, and another type was with natural ventilation through ceiling duct while both types used mechanical ventilation system with the outlets. The indoor temperature distribution and pollution density distribution in summer while operating the ceiling air conditioner were analyzed through CFD simulation. In this paper, the optimal location of diffusers to achieve thermal comfort would be proposed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.150-159
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• 2021

This study aimed to prevent inconvenience to electric vehicle users caused by an interruption of charging by the earth leakage breaker trip that occurs during charging. As a field case study, it was confirmed that during the battery charger failure type, leakage current measurement experiment by vehicle type, and leakage current breaker operation experiment, the internal temperature of the charger rose to more than 60 ℃ in summer, and the earth leakage circuit breaker stopped charging by tripping at 80% of the rated sensitivity current. Through Joule heating modeling, 32A is energized at the reference temperature of 30 ℃ at the initial time t=0 (s). After t=3000 (s), the heat generated around the charging part of the earth leakage breaker increased to 32.4 ℃. The temperature and time factors correlated with the amount of heat generated according to the statistical verification tool with a correlation coefficient of 0.97. Overall, it is possible to prevent the leakage breaker sensitivity current trip due to an increase in temperature inside the charger in summer by performing a Joule heating simulation according to the material of the charging case, the arrangement of the internal wiring, and the dielectric medium when developing the charger device.