• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.5
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• pp.556-561
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• 1995

Persisent circadian rhythms in carbon assimilation, stomatal conductance and soluble carbohydrate concentration were investigated during grain filling period in rice plant transferred from a natural photoperiod to constant conditions. A weak rhythm in photosynthesis, measured as carbon assimilation, and stomatal opening, as conductance to water vapor, with a period of approximately 24-hours, occurred under constant condition. Carbon assimilation and stomatal conductance reached maximum values near noon and minimum values near midnight during the early stage (until 72-hour) after transferring to constant condition, and then the amplitude and phase were changed slowly, the rhythms with little damping, reaching maximum values near midnight and minimum values near noon during 96~120-hours after transferring. However, photosynthesis in plants grown for 14days after anthesis under constant moderate light(day and night) did not oscillated in constant condition unlike plants grown under a cycle of light and darkness. These phenomenon was observed in soluble carbohydrate concentration in flag leaves as well. Evidences from several approaches indicate that endogenous rhythms of $CO_2$ assimilation, stomatal conductance and soluble carbohydrate concentration are closely couped with each other and particularly important to plants, which depend on the natural day-night cycle as a external signal.

• Applied Chemistry for Engineering
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• v.24 no.6
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• pp.656-662
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• 2013

The iron oxide ($Fe_3O_4$) particles in the coolant of the secondary system of a nuclear power plant reduce the heat transfer performance or induce corrosion on the surface of the heat transfer tube. To prevent these problems, we conducted a study to improve the dispersion stability of iron oxide using polymeric dispersant injection in simulated secondary system water. The three kinds of anionic polymers containing carboxyl groups were selected. The dispersion characteristics of the iron oxide particles with the polymeric dispersants were evaluated by performing a settling test and measuring the transmission, the zeta potential, and the hydrodynamic particle size of the colloid solutions. Polymeric dispersants had a significant impact on the iron oxide dispersion stability in an aqueous solution. While the dispersant injection tended to improve the dispersion stability, the dispersion stability of iron oxide did not increase linearly with an increase in the dispersant concentration. This non-linearity is due to the agglomerations between the iron oxide particles above a critical dispersant concentration. The effect of the dispersant on the dispersion stability improvement was significant when the dispersant concentration ratio (ppm, dispersant/magnetite) was in the range of 0.1 to 0.01. This suggests that the optimization of dispersant concentration is required to maximize the iron oxide removal effect with the dispersant injection considering the applied environments, the iron oxide concentration and the concentration ratio of dispersant to iron oxide.

• Korean Journal of Ecology and Environment
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• v.47 no.3
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• pp.194-201
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• 2014

To elucidate which climate factors and what periods affect the time of breeding migration of Gori salamanders (Hynobius yangi), we have investigated relationships between the 5-years breeding monitoring data from 2006 to 2010 which had obtained in both natural and translocated breeding sites at Bongdae mountain, Gijang-gun, Busan-si and the matched climate data obtained from the weather station, approximately 25 km apart from the sites. Mean average and mean lowest temperatures during one month before the first breeding migration were related with the time of first female migration in the translocated site. Mean temperature variation and mean precipitation during 60~120 days before the first breeding migration affected the time of 30% male appearance at the natural site and the time of 30% female appearance at both natural and translocated sites. Climate factors were more closely related with female appearance than male and at the translocated site than at the natural site. Our results show that changes in mean temperature variation and mean precipitation rather than mean average temperature might more significantly affect the breeding migration of salamanders, female breeding migration is more closely related with climate factors, and the salamanders translocated could be more affected by climate changes than those in natural populations.

• Korean Journal of Poultry Science
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• v.27 no.2
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• pp.115-132
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• 2000

Eggshell strength and eggshell pigmentation are described in this paper since these are needed for quality egg production. A strong eggshell is determined by the components of the shell (cuticle, true shell and membranes) as well as the proper function of the gastrointestinal tract, the shell gland, the Kidneys and the endocrine system. When the puller reaches sexual maturity, the medullary bone must be ready for the laying hen at the peak egg shell formation. The amount of calcium in the layer diet, sources of calcium feed, the ratio of calcium and phosphorus in the layer diet, adequate levels of vitamin D and the dietary mineral (electrolyte) balance in the body fluid are important factors along with the levels of other nutrients. Biological, environmental and managerial factors such as the age of laying flock, temperature and humidity of the hen house, bird strain, disease, egg collection through transportation and others and influence the shell breakage at various stages of movement of the eggs from the producer to the consumer. The pigments present in eggshells are protoporphyrin-Ⅸ, biliverdin-Ⅸ and its zinc chelate and occasional traces of coproporphyrin-Ⅲ. However, there are several causes of changes in eggshell pigmentation such as the age of hen, disease, drugs and surface defects due to abnormal post-cuticular deposits.

• Proceedings of the KOR-KST Conference
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• 1996.02a
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• pp.29-58
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• 1996

현재 서울은 교통사고문제, 교통혼잡문제와 자동차로부터 배출되는 유해가스에 의한 대기환경오염문제를 갖고 있다. 본 논문의 목적은 대기환경오염을 악화시키는 자동차의 주된 배출오염가스인 일산화탄소, 탄화수소 및 질소화합물량을 교차로 교통량을 중심으로 어떻게 계산하는가에 있다. 연구의 대상지역은 서울시의 송파구 교차로들과 도심지역의 링크들을 선택하였다. 그리고 교통량, 지체시간, 링크길이, 정지회수, 운행속도, 주행속도 등을 고려하여, 제작차 배출가스 허용기준, 총량기준, 불량차 기준, 속도기준 등에 의한 계수산정 및 TRAF-NETSIM에 의한 시뮬레이션을 통하여 일정 도로상의 제한된 범위내의 배출량 산출을 시도하였다. 본 연구의 결과에 의하면 첫째, 어느 방법이든 실제배출량의 정확한 값을 표현 할 수는 없는 것이고, 단지 상대적인 비교에 의하면 배출가스량의 수준을 추정 할 수 있었다. 또한, 시뮬레이션 배출율표를 우리 현실에 맞는 자료에 의해 수정할 수 있다면, 그 결과는 실제량에 보다 근접할 수 있을 것이다. 둘째, 서울도로의 현재 혼잡상태에서 속도의 저감에 배출량이 민감한 반응을 보이고 있다는 사실이다. 셋째, 교통량변화에 따른 배출량의 변화가 일산화탄소에서 가장 심하게 나타남을 알 수 있었고, 신호운영상의 옵셋값이 잘못 설정되면 탄화수소는 35%, 일산화탄소는 40%, 질소산화물은 75%까지 초과발생할 수 있으며, 유해배출가스량을 최소화시키는 측면에서의 신호최적화를 위해서는 현재의 Stop Penalty는 상향 조정되어야 함이 밝혀졌다. 앞으로는 자동차로 인한 대기환경오염 농도의 저감을 위해서는 도로별 자동차 유해가스 배출 총량규제 방안도 고려해 볼 가치가 있으며, 이를 위해 환경공학과 교통공학의 다학제적 공동연구가 지속적으로 필요하며 교통정책에 반영되어야 할 것이다.분석, 리용수 학모형대이십일세기상해항공운량진행예측, 제출발전상해항공운수적전 략목표급발전중점. 예측2020년 상해항공항총객운탄토량4300만인/년, 화운량달120만돈; 2050년객운량장달18150만인차/년, 화운량518만돈. 사, 발전상해민항기출경제정책, 제출위료$\ll$진흥상해, 개발포동, 복무전국, 면향세계$\gg$ 화도이십일세기중기국민경제달도중등발달국가수 평굉관전략목표적실현, 제료필수재지도사상상파교통운수진정방도전략 산업지위, 환응재관리체제상채취과단유효적개혁조시, 재기출경제정책 상급여대력부지. 오, 전략목표, 위파상해건설성위태평양서안최대적경제, 김융, 무역적중심, 요구상해항공항성위화동지구통향세계각지항선망출발참, 구성대외개방선면축심, 실현국제항선적함접화국내항반적전항, 형성다축심복사식항선망; 가강기장건설, 개피포동제이국제기장건설, 괄응포동개발경제발전적수요. 부화개시일은 각 5월 26일과 5월 22일이었다. 11. 6월 중순에 애벌레를 대상으로 처리한 Phenthoate EC가 96.38%의 방제가로 약효가 가장 우수하였고 3월중순 및 4월중순 월동후 암컷을 대상으로 처리한 Machine oil, Phenthoate EC 및 Trichlorfon WP는 비교적 약효가 낮았다.>$^{\circ}$E/$\leq$30$^{\circ}$NW 단열군이 연구지역 내에서 지하수 유동성이 가장 높은 단열군으로 추정된다. 이러한 사실은 3개 시추공을 대상으로 실시한 시추공 내 물리검층과 정압주입시험에서도 확인된다.. It was resulted from increase of weight of single cocoon. "Manta"2.5ppm produced 22.2kg of cocoon. It is equal to 9% increase i

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.5
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• pp.754-763
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• 2018

The maritime ICT-convergence equipment are essentially required to a type approval (TA) certification that needs environmental and functional tests, to install in vessel. The environmental test is to experiment the possession for required durabilities of the target device in maritime environment, and the functional test is to check the required functions of target equipment based on international standard. In Korea, the environmental testing facilities amount to 227 sites, but there is no functional testing facility. Because of this, we establish a function test facility for the maritime ICT-equipment. In this paper, we analyze and design the functional testing requirement and required interlocking simulators for digital interfaces and navigation communication equipment. We propose the 2-steps of functional testing procedures, which are single test and integration test, to improve the reliability of testing result. The single test is to examine own functions of the target device, and the integration test is to check harmonized operation with other navigation and communication devices.

• Economic and Environmental Geology
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• v.39 no.6 s.181
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• pp.689-697
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• 2006

Distribution and speciation of arsenic in water resources was investigated in the Ulsan mine area. In 62% of uoundwater samples from the mine area, total As concentrations exceeded 0.05 mg/l, the Korean Drinking Water Standard. As(V) was the major type in groundwater with minor As(III). Arsenic species appeared to be in transition stages following redox changes after exposure to the air through the monitoring wells. In areas around the mine, the mine and Cheongog spring appeared to be the sources of arsenic contamination of water resources. The spring showed 0.345 mg/1-As, as much as seven times of the Korean standard. Groundwater and stream samples showed As-concentrations greater than 0.05 mg/l in 30% and 33% samples, respectively, and 60 and 67% of samples exceeded 0.01 mg/l of WHO guideline, respectively. Again, As(V) was a dominant species, however, several samples had As(III) in appreciable levels. In one stream sample, organic species including DMA and AsB were detected in low levels, probably resulted from transformation or related biogeochemical processes.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.5
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• pp.269-278
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• 2016

In order to improve air quality in the Seoul Metropolitan Area (SMA), the "Special Act on Seoul Metropolitan Air Quality Improvement" has been enforced since 2005. The strategy has resulted in some reduction of air pollution, but there has not been much research into the quantitative impact analysis of each separate preventive countermeasure. Therefore, we analyzed nitrogen oxide reduction resulting from implementation of the emission control plan for on-road mobile sources. The MM5-SMOKE-CMAQ model system was employed for air quality prediction. Reduced $NO_x$ emissions for SMA was 16,561 ton, 4.7% of reduction rate, in 2007. One countermeasure, tighter acceptable standards for manufacturing vehicles, dominated other countermeasures for effective $NO_x$ emission control. Large spatial differences in reduced emissions, those for Seoul being twice that of Incheon and Gyeonggi, showed greater $NO_x$ emission reduction impact in the heart of the metropolitan complex. The $NO_2$ concentration decreased by 0.60 ppb (2.0%), 0.18 ppb (1.5%), and 0.22 ppb (1.7%) in Seoul, Incheon, and Gyeonggi, respectively. Concentration decreases in spring and winter were larger, 1.5~2.0 times, than summer and fall. However, the $NO_2$ reduction impact did not correspond directly to local $NO_x$ emission controls in the city area because of the natural flow and dispersion, both urban and downwind.

• Korean Journal of Environment and Ecology
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• v.18 no.4
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• pp.359-368
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• 2004

The purpose of this study is to examine distribution and damages of the trails of inquiry of urban natural parks. Those parks were located at south-north green corridor at Incheon being mountainous type of urban natural parks that were core area of urban ecosystem preservation to of urban natural parks that citizens recently made use of them as nature experience type of leisure and recreation place from time to time, and to supply basic material deciding on the ways to improve the trails of nature preservation type. The survey sites included Geyang Park, Baekma Park, Yaksa Park, Munhak Park and Cheongryang Park. The number of main trails was 42 at Geyang Park, 43 at Baekma Park, 9 at Yaksa Park, 28 at Munhak Park, and 22 at Cheongryang Park, and it was excessively more than optimum needed: The number of branch trails of the parks seemed to increase. The bared trail width in average of the roads was 3.5m, while maximum depth in average was 21.3cm. The trails were thought to be deteriorated rapidly without systematic maintenance. The 5th and 6th grade of the impact rating class that required restoration because of serious deterioration occupied 19.6∼78.0%. Based on the findings, the study suggested ways to improve and manage the trails of inquiry of urban natural parks that were placed at south-north green corridor at Incheon.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.3 no.3
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• pp.12-19
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• 2000

The purpose of this study is to evaluate the channel changes according to the temporal and spatial distribution of the deposition area by the vegetation invasion in Kyesung-river. The deposition area mainly occurred by landslide and debris flow from the headwater channel. And also the movement of subsequent downstream depends upon the site of deposits by a varity erosional processes. As the age of deposition area is older, it had a tendency to stable by plant invasion relatively. The vegetations grown in deposition area were very effective to estimate a historical deformation process of river-bed occurred by landslide. The vegetations around deposition area consisted of the same as tree species grown in forest area of circumference like Pinus densiflora, Styrax japonica, Quercus acutissima and Salix gracilistyla. If the torrential stream is flooding, the deposition area of 1 to 5 years can be change to the channel easily. Deposition area of 11 to 23 years had a high river-bed because it passed long time since deposited, and amount of sedimention is much more in wide than in narrow channel. It is consider that the change of channel had many influenced by the span of survial time, scale and movement frequency of deposition area after the vegetation invasion.