• Economic and Environmental Geology
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• v.51 no.6
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• pp.485-492
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• 2018

About 300 thousand tones of oyster shells are produced annually and, thus, their massive recycling methods are required. Recently, a method, utilizing them as wet desulfurization materials after removal of organic matters and changing $CaCO_3$ phase into CaO through calcination, is under consideration. This study investigates the mineralogical changes (specific surface area, phase changes, surface state, etc.) of oyster shells by calcination and their characteristics were compared with those of limestone. Uncalcined oyster shells showed the higher specific surface area than limestone because the former are composed of platy and columnar structures. In contrast, investigated limestone showed a dense structure. The phase change of oyster shells occurred at lower temperature than that of limestone. The specific surface area of oyster shell decreased significantly after calcination while limestone depicted a drastic increase. Small amount of Na contained in oyster shell was suggested as the cause of this phenomenon; in that, it acted as a flux causing melting and sintering of oyster materials at lower temperature. Because of this, an additional phenomenon was observed that a part of shell materials remained untransformed even at higher calcination temperature and after longer treatment period due to the sintered surface, which covers the rest parts. Further studies investigating the effect of this phenomena from the perspective of desulfurization is required.

• Clinical and Experimental Pediatrics
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• v.45 no.12
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• pp.1551-1558
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• 2002

Purpose : Loss of hippocampal interneurons in dentate gyrus has been reported in patients with severe temporal lobe epilepsy and in animals treated with kainic acid(KA). Interneurons contain $Ca^{2+}$- binding protein parvalbumin(PV). The effects of kainic acid on parvalbumin-immunoreactive (PV-IR) interneurons in dentate gyrus were investigated in organotypic hippocampal slice cultures. Methods : Cultured hippocampal slices from postnatal day nine C57/BL6 mice were exposed to $10{\mu}M$ KA, and were observed at 0, 8, 24, 48, 72 hours after a one hour KA exposure. Neuronal injury was determined by morphologic changes of PV-IR interneuron in dentate gyrus. Results : Transient(1 hour) exposure of hippocampal explant cultures to KA produced marked varicosities in dendrites of PV-IR interneuron in dentate gyrus and the shaft of interbeaded dendrite is often much thinner than those in control. The presence of varicosities in dendrites was reversible with KA washout. The dendrites of KA treated explants were no longer beaded at 8, 24, 48 and 72 hours after KA exposure. The number of cells in PV-IR interneurons in dentate gyrus was decreased at 0, 8 hours after exposure. But there was no significant difference in 24, 48 and 72 hours recovery group compared with control group. Conclusion : The results suggested that loss of PV-IR interneurons in dentate gyrus is transient, and is not accompanied by PV-IR interneuronal cell death.

• Applied Microscopy
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• v.33 no.4
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• pp.299-313
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• 2003

The aim of the present study was to assess the role of protein kinase C (PKC) in the development of cardiac injury following scald burn. Sprague-Dawley rats were induced a scald burn a 15% total body surface area. Phorbol 12-myristate 13-acetate (PMA, 2 mg/kg) and bisindolylmaleimide (BIS, 0.05 mg/kg) were immediately administered i.p. after burn injury. 5 h and 24 h later, heart was removed and examined biochemical assay, ultrastructural changes and stereological analysis. The activity of serum aspartate aminotransferase was significantly increased at 5h (p<0.01) and 5h+BIS (p<0.001) after burn compared with that of control. The activity of serum creatinine was significantly decreased in PMA-treated groups after burn compared with postburn 5 h. PMA caused a decrease in MPO activity and induced wavy fibers in cardiac myocytes at postburn 5 and 24h. BIS induced contraction band, separation of intercalated disk and abnormal mitochondria in cardiac myocytes at postburn 5 and 24h. In stereological analysis, treatment of rats with PMA increased volume density of myofibril and mitochondria compared with postburn 5 and 24h. Our data suggest that the activation of PKC in scald burned heart decreases inflammation and protects the myocardium.

• Microbiology and Biotechnology Letters
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• v.2 no.3
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• pp.127-131
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• 1974

Inhibition of over-oxidation of prednisolone in the fermentation has been studied by using vegetative cells as enzyme source. firstly, A. simplex (ATCC 6946) was demonst.ated to degrade p.ednisolone in the vegetative culture of the microorganism. Over 72％ of hydrocortisone was transformed into prednisoloneby 3 hours of the fermentation. However, the prednisolone produced was considerably oxidized forming over-oxidation product in 8hours of fermentation period with the intact cells. Secondly, in order to depress the over-oxidation and the breakdown of the steroid skeleton of prednisolone, chelating agents such as $\alpha$$\alpha$'-dipyridyl, o-phenanthroline and 8-hydroxyruinoline were added to the fermentation broth. Conseauently, the breakdown of prednisolone by the iutact cells was able to be remarkably retatded and an intermediate regarded as an oxidized product derived from prednisolone was accumulated, by the addition of $\alpha$$\alpha$'-dipytidyl in the fermentation.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.37-37
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• 2020

일반적으로 생활용수 및 공업용수의 경우 대부분 주수원으로 댐 및 저수지 등을 통해 용수공급이 이루어지며, 일부 지역에서는 하천에서 직접 취수가 이루어지고 있다. 그러나 하천을 수원으로 사용하고 있는 대부분의 지점에서는 계측이 이루어지고 있지 않아 정확한 양을 파악하기 어려운 실정이다. 이러한 현상이 지속 될 경우, 하천 관리를 위한 정확한 가용수량 파악을 통한 수자원 계획 수립 및 수문학적 가뭄정보 생산시 어려움이 수반된다. 수문학적 가뭄 정보를 보다 정확하게 제공하기 위해서는 유역 내 물순환체계 구축, 수문기상 빅데이터 활용, 정확한 유역유출모델링 등 다양한 요소들이 통합적으로 연계되는 것이 무엇보다도 중요하다. 더불어 유역 내 전반적인 물수급 체계를 조사 및 분석하고, 이를 기반으로 모델을 구축하는 것이 선결되어야 할 것으로 판단된다. 이러한 점에서 본 연구에서는 실적기반 가뭄 모니터링을 위한 시공간적으로 상세화 된 물순환 모형을 개발하는데 목적이 있으며, 이를 통해 준실시간으로 하천을 중심으로 가뭄 모니터링이 필요한 지점에 유량을 제공할 수 있는 체계를 개발하고자 한다. 즉, 가뭄에 대해 선제적으로 대응하기 위해서 모니터링 현황, 분석 및 전망 그리고 가뭄 발생지역을 보다 신뢰성 있게 판단하기 위한 가뭄정보 기술정보 제공이 가능한 모형이라 할 수 있다. 이를 통해 궁극적으로 댐, 저수지, 하천 등 다양한 수원을 가지는 유역 내 가용수자원량을 보다 정확하게 판단하여, 다양한 수자원 계획 수립시 기초자료로 활용 될 수 있을 것으로 기대된다.

• Journal of Korea Water Resources Association
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• v.48 no.6
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• pp.463-477
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• 2015

The recent unusual climate and extreme weather events have frequently given unexpected disaster and damages, facing difficulties in the management of water resources. In particular, climate change could result in intensified typhoons, and this would be the worst case scenario that can happen. The primary objective of this study is to identify the patterns of typhoon-induced precipitation and the associated synoptic pattern. This study focused on analyzing precipitation patterns over the South Korea using historic records as opposed to a specified season or duration, and further investigates the potential connection with heavy rainfall to synoptic patterns. In this study, we used the best track data provided by the Regional Specialized Meteorological Center of Japan for 40 years from 1973 to 2012. The patterns of the typhoon-induced precipitation were categorized into four groups according to a given typhoon track information, and then the associated synoptic climatology patterns were further investigated. The results demonstrate that the typhoon-induced precipitation patterns could be grouped and potentially simulated according to the identified synoptic patterns. Our future work will focus on developing a short-term forecasting model of typhoon-induced precipitation considering the identified climate patterns as inputs.

• Korean Journal of Ecology and Environment
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• v.33 no.4 s.92
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• pp.342-349
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• 2000

This paper demonstrates the influence of intensity of the monsoon on morpho-hydrological fluctuations in Taechung Reservoir during 1993${\sim}$1994. During the study, hydrological variables including rainfall, inflow, and discharge volume showed distinct contrast between 1993 and 1994. Interannaul differences in rainfall occurred during the monsoon in July${\sim}$August monsoon and influenced inflow, discharge, and water residence time (WRT). Total inflow in 1993 was four times greater than that of 1994, and summer inflow in 1993 was 8 times greater than summer 1994. Annual Mean WRT was 93.2 d in 1993 vs. 158.6 d in 1994 and the largest differences occurred between monsoons of 1993 and 1994. Morphometric variables reflected the interannual contrasts of hydrology, so that in 1993 surface area, total volume, shoreline development, and mean depth increased consistently from premonsoon to postmonsoon and over this same period in 1994 they decreased. This outcome indicates that the area of shallow littoral zones in 1993 was greater than in 1994. Also, the drainage area to surface area (D/L) at 80 m MSL was 60.7 which was much greater than values in Soyang and Andong reservoirs and natural lakes world-wide. The morpho-hydrodynamic conditions seemed to influence in-reservoir nutrient concentration which is one of the most important factors regulating the eutrophication processes. I believe, under the maximum hydrodynamic fluctuations in Korean waterbodies during the monsoon, applications of mass balance models to man-made lakes for assessments of external loading should be considered because the models can be used under the seasonally stable inflow and water residence time.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.4
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• pp.415-420
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• 2010

Cryptographic keys for security should be generated by true random number generators that apply irreversible hashing algorithms to initial values taken from a random source. As DRAM shows randomness in its access latency, it can be used as a random source. However, systems with synchronous DRAM (SDRAM) do not easily expose such randomness resulting in highly clustered random numbers. We resolved this problem by using the xor instruction. Statistical testing shows that the generated random bits have the quality comparable to true random bit sequences. The performance of bit generation is at the order of 100 Kbits/sec. Since the proposed random number generation requires neither external devices nor any special circuits, this method may be used in any computing device that employs DRAM.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.996-1000
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• 2009

물순환계를 종합적으로 관리하기 위해서는 물순환계의 모니터링과 해석모형의 구축이 필요하다. 실측자료만으로는 복잡 다양한 물순환계 구조 및 인과관계를 규명할 수 없기 때문에 시간적 공간적으로 변화하는 다양한 수문현상을 일관된 하나의 시스템으로 이해하기 위해 물순환 해석모델을 구축하여 검토할 필요가 있다. CAT(Catchment hydrologic cycle Analysis Tool)은 수문학적으로 균일하게 판단되는 범위를 소유역으로 분할하여 지형학적 요인에 의한 유출 특성을 객관적으로 반영할 수 있게 하며, 토양층에 따라 침투, 증발, 지하수 흐름 등의 모의가 가능하도록 하는 Link-Node 모형으로, 증발산은 기준 증발산을 외부에서 직접 입력하거나, Penman-Monteith 방법을 선택할 수 있으며, 침투는 토양의 수리전도도에 따른 연직방향 침투 및 사면방향 복귀류를 고려할 수 있다. 노드의 지하수 유거를 고려하여 기존 노드-링크 방식 모형의 장기 유출 해석시 제한점을 보완하였으며, Muskingum, Muskingum-Cunge, Kinematic wave 방법을 이용하여 하도추적을 모의할 수 있다. 또한 GUI를 통해 사용자가 손쉽게 모형을 적용하고 관리 할 수 있도록 하고, 여러 시나리오를 적용함에 있어서 편리하도록 개발 중인 모형이다. 본 연구에서는 개발중인 CAT 모형을 평가 하기위해 시험 유역으로 운영 중인 설마천 유역에 적용하여 소유역 분할(노드수), 계산 시간 간격(일/시단위) 등에 따른 적용성을 평가하였다. 관측 자료를 통해 구축 가능한 물리적 매개변수를 통해 해당 유역을 단일 노드 및 다중 노드로 간단히 모형화할 수 있었으며, 모의 결과, 관측 유량과 적절히 일치하는 결과를 얻을 수 있었다. 1시간 단위에 대한 모의에서도 유출을 적절히 모의할 수 있었으며, 소규모 유역에 대한 정밀한 물순환 해석이 가능할 것으로 평가되었다.

• Korean Journal of Ecology and Environment
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• v.37 no.3 s.108
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• pp.263-271
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• 2004

To collect the basic ecological information about the microbial food webs in eutrophic water system with different residence time, the monthly variation of bacterioplankon (bacteria and small-sized cyanobacteria) and nanoplankton (phytoplankton and protists) were examined from December 2000 to September 2001. Kyungan stream is shorter in resident time (ca.5.4 d) than Seokchon reservoir (ca.72 d), even though they showed the same pattern in precipitation. With the basic environments, we examined the biomass (standing crops and its carbon content) of each plankton collected from the surface water. Large-sized planktons flourished in the time of low temperature, while small planktons were in the time of the high temperature period. Especially, in the Kyungan stream with much disturbance by rainfall and outflow, high diversity showed in term of species and cell morphology, compared to that of Seokchon lake. The time-lag relationship remarkably showed between phytoplankton and bacteria in Seokchon reservoir, and between protists and bacteria in Kyungan stream, respectively.