• Journal of Wetlands Research
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• v.19 no.4
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• pp.409-422
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• 2017

In order to understand the environmental factors affecting the waterbird community in winter, we divided the watershed into 6 sections and investigated the size of the stream, the water quality, benthic invertebrates, and fish including birds. The influences on the community of water birds in Wonju stream were river structure, temperature and water quality. Among the structure of the river, the factors affecting the waterbird community in winter were the width of the stream and the width of the flowing water. The wider the width, the more species and the number of the winter waterbirds were. As the width of river water was wide, the smaller the width and width of the waterway, the fewer the population. The temperature changes of the wintering season affected the community of water birds because it led to freezing of rivers. The sections that were not frozen showed a significant increase and decrease in the temperature drop and rise. The values of pH, water temperature, COD, BOD, TN, TP and total E. coli increased with the increase of the downstream waterbirds population in the water quality survey. The water quality of S6 was affected by the downstream sewage treatment plant The number of wintering waterbirds was also highest. The effluent from the sewage treatment plant seems to have a considerable influence on the water quality. The increase of several items such as TN promotes the nutrition of the river, which leads to the accumulation of organic matter and the proliferation of aquatic organisms. This may be the cause of the increase in winter waterbirds as a food source. The benthic macroinvertebrate communities and fish communities did not show any correlation with the wintering water-birds communities.

• Journal of the Korea Organic Resources Recycling Association
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• v.20 no.2
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• pp.44-52
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• 2012

As an alternative strategy in the era of high level petroleum cost, the study focused to suggest the way on the revitalization of renewable energy through the impact on introduction effect of renewable energy in green village. Total feasible solar energy production is 6.73 GWh/yr along with the biomass energy producing electric power energy is 134.06 GWh/yr, the two category's total electric power energy is 233.19 GWh/yr, which is possible to achieve the selfsufficiency of energy by 33% for total energy consumption of 705.80 GWh/yr in the region. The calculated feasibility on the carbon dioxide reduction, carbon dioxide reduction level is 1,891 ton_$CO_2$ by agricultural byproducts, 43,635 ton_$CO_2$ by livestock waste, 395 ton_$CO_2$ by municipal waste, 50,324 ton_$CO_2$ by forest byproducts, the total biomass shows 96,245 ton_$CO_2$, while the carbon dioxide reduction of solar light energy is 2,251 ton_$CO_2$, 1,383.3 ton_$CO_2$ by solar heat energy, the total solar energy shows 3,634 ton_$CO_2$. So total carbon dioxide reduction effect shows 99,879 ton_$CO_2$.

• Journal for History of Mathematics
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• v.22 no.3
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• pp.79-102
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• 2009

Most who have heard of Sang-Seol Lee know him for his contribution to the Korean independence movement nearly a hundred years ago. This paper, however, will discuss Lee's other great contribution to his country; that of being "The father of modern mathematical education in Korea". Lee passed the rigorous government officer examination with the highest honor and became a teacher for the royal prince. Later he became the president of Sunkyunkwan, a national institute of higher learning since 1398, and eventually a well-known university bearing the same name. Lee was also a highly regarded Confucian scholar and well versed in foreign languages. He wanted Korea to become a modern country and felt that the areas of science and engineering were studies that needed improving in order to achieve modernization. While researching Western textbooks on the subjects he realized that Western mathematics would be especially important for Korea. With that, it became his mission to integrate Western mathematics into the Korean educational system. This paper will explain the importance of Sang-Seol Lee's contributions to mathematic education in Korea and how it helped Korea become the modern nation it is today.

• Parasites, Hosts and Diseases
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• v.35 no.4
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• pp.245-250
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• 1997

The responses of gastric mucosal mast cells (GMMCS) to infection with coccid- ian protozoa, Clptosporinium muris, in mice were examined during primary and challenge infections. Each of three-week-old ICR SPF mice was orally inoculated with a single dose of 2 × 106 oocysts of C. muffs (strain MCR). After oocyst shedding ceased, the mice were orally challenged with a single dose of 2×106 oocysts of the same species. GMMCS reached a peak on days 20-30 postinoculation (Pl) in number, and decreased thereafter. An increase on days 20-30 post-challenge-infection (PCI) was also observed. The mice showed, on the whole, normal profiles of oocyst shedding in droppings. The number of the cells of uninfected control mice remained constant. .Tudging from the above results, it is suggested that mastocytosis correlate with expulsion of C. mans in primary infection and the defense mechanism of challenge infection.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.2
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• pp.73-79
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• 2006

Aeration is the most important and indispensable operation unit for the treatment of swine manure using aerobic liquid-composting process. The composting of swine manure depends on biological treatment process, but the highly concentrated ammonia nitrogen is required a pretreatment to expect the appropriate efficiency of the biological treatment process. In this study, pilot experiments have been carried out to estimate of the fit condition about ammonia stripping process as a pretreatment to aerobic liquid- composting. pH adjustment with $Ca(OH)_2$ was economically superior to use of NaOH and optimum pH of ammonia stripping was 12.3, ammonia nitorgen was rapidly removed as pH were increased at $$35^{\circ}C$$. When air stripping is performed before aerobic liquid-stripping, a high initial pH is required for complete ammonia removal and is additional effects such as organic substances, phosphorus, turbidity, and color removal. Stripping process was very efficient in the pretreatment of highly concentrated ammonia nitrogen for composting of swine manure. Emission rate of gaseous ammonia was $0.5355mole\;s^{-1}$ at initial time and $0.0253mole\;s^{-1}$ at finitial time. The fit condition of ammonia stripping in this study were at the temperature of $$35^{\circ}C$$, and the pH of 12.3 during 48 hours.

• Current Industrial and Technological Trends in Aerospace
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• v.6 no.1
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• pp.3-13
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• 2008

The year 2007 marked two important anniversaries for space. The Soviet Union launched Sputnik 50 years ago on October 4. 1957. The 40th anniversary of the United Nations treaty on outer space was also marked in 2007. 2008 and 2007 were full of dramatic events of space activity as well : Success of Japan's first large lunar explorer 'KAGUYA'(SELENE) and China's 'Chang'e 1', launch of ISS laboratory module, 'Colombus' and 'Kibo', test of China's ASAT, and success of Korea's first astronaut program and so on. International government space budgets reached $78.3 billion in 2007, a strong growth rate of 36% over 2006, and the recently released Global Exploration Strategy, The Framework for Coordination is a set of guidelines for international cooperation among 14 of the world's space agencies. Worldwide space industry revenue grew by 20% over 2005, $106.1 billion in 2006 and $173.9 billion expected in 2007. This paper discusses the issues related to the Earth observation R&D trend and market in detail. Korea's 2008 government space spending is \316.4 billion, 2007 space industry revenue was $106 million. Several research projects are now underway and STSAT 2 will be launched by KSLV-1 at the Naro Space Center within this year.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.88-92
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• 2017

Owing to the depletion of fossil energy, wind power is attracting attention as a promising environmentally friendly alternative energy source, because it is abundant, renewable, and non-polluting. Wind turbines are divided into horizontal axis wind turbines (HAWTs) and vertical axis wind turbines (VAWTs) according to the direction of the rotating shaft. VAWTs have a low power generation efficiency, but are not affected by the wind direction and, thus, no yaw system is required and their structure is simple. Small VAWTs are attracting much attention because they can generate power even at low wind speeds. In this study, the output voltages and output currents of small VAWTs with gyromill type, hinge type and double door type blades capable of generating power even at low wind speeds were analyzed at variable wind speeds in the range of 1~11 m/s. At the maximum wind speed of 11m/s, the application of the double door type blades achieved 67% and 9% higher wind turbine output voltages than that of the gyromill type and hinge type blades, respectively. As regards the wind turbine output currents, the application of the double door type blades gave rise to 93% and 5% higher results than that of the gyromill type and hinge type blades, respectively. Through this study, the excellent output characteristics and commercialization potential of the double door type blades, which can generate power both at low and high wind speeds, were confirmed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.57-64
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• 2017

Today, due to the environmental regulations regarding air pollution in the EU, the use of EPS (Styrofoam) as the cushioning material in the packaging industry is decreasing. In effect, air cushioning based cushioning materials are rapidly expanding into the market and replacing EPS, due to their excellent buffering ability and environmental friendliness. This is a new selective filling type air filling material manufacturing technology that affords improvements in the amount of raw materials required, its processing and its aesthetic appearance compared to the conventional air filling cushioning materials. In this study, a multi-stage air cell filling valve molding technology is developed based on selective filling technology, which allows packages to be selectively filled in various forms by applying valve forming structure technology. This multi-stage air cell filling valve molding technology is a technique in which a plurality of injection ports are formed by laminating three layers of films, viz. a first injection film, a valve film, and a second injection film having valve ends. In the conventional technology, a separate external air injection path for injecting air into a plurality of connected air bags is needed. However, in the proposed system, an external air injection path is formed inside the air bag, Due to the lack of need for an injection furnace, the raw material and process are reduced and air is injected and then discharged, while the air bag is reduced in length to 63 ~ 66% of its normal value. The outer surface of the outer air injection path is integrated inside by maintaining the original length of the cross section, while the unnecessary folded air is injected into the interior of the air bag, This smart air filling type cushioning material manufacturing technology constitutes a big improvement over the existing technologies.

• The Korean Journal of Pesticide Science
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• v.16 no.4
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• pp.322-327
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• 2012

Fate of fenitrothion aerially sprayed to control pine wood nematode (Bursaphelenchus xylophilus) was studied in a forest of Haman area. And the monitoring of fenitrothion was conducted in a stream flowed from forest area of Gijang sprayed fenitrothion. Fenitrothion 50% EC was diluted 100 times and applied two or three times using helicopter in Haman and Gijang, respectively. Average fenitrothion deposits on forest floor ranged from 6% of standard aerial application rate. Following to the second application, fenitrothion deposits in the pine needle ranged from 0.6 to 0.9 mg/kg and then rapidly decreased to 0.01 mg/kg after 109 days. Deposits on the plant washed off by rainfall and reached to soil surface was 1.3% of the application rate. All of fenitrothion on the ground resided in the forest floor covering the soil surface, where fenitrothion residues were decreased to a tenth at 109 days after the second application, but they were not detected in sol beneath it. And the only low level of fenitrothion residues, 0.0009 mg/L, was detected in runnel of the experimental forest just after aerial application. The concentration of fenitrothion in effluent from Gijang area was less than detection limit (0.0001 mg/L) during the entire period.

• Korean Journal of Ecology and Environment
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• v.38 no.1 s.110
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• pp.105-117
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• 2005

During the period of heavy rain from 2002 to 2004, the characteristics of the inflow, temporal and spatial fluctuations of high turbid water according to thermal stratification were studied on the Andong Reservoir which is the largest artificial lake in the Nakdong River basin, Korea. Thermal stratification was formed in June. Its structure determined to the pathway of inflowing turbid water and has affected by the transportation of high turbid water. Regardless of the time and amount of inflow, the high turbid water showed the shape of underflow at the riverine zone, separated from the bottom at the transition zone and moved to the lacustrine zone with the shape of density current. The plunging point depended on the time and amount of inflow. The distributions of thermal stratification and DO concentrations were changed by inflowing discharge. Two thermoclines and minimum DO layers were found out existing at metalimnion in a specific time, respectively. The layer of high turbid water which formed with the thickness of 20 m at the maximum below the depth of 15 m moved toward dam. Not settled to the bottom, the newly formed layer was discharged through the intake-outlet and dispersed into all layers by the circulation in the fall.