COAL COMBUSTION CHARACTERISTICS IN A CIRCULATING FAST FLUIDIZED BED

Lee, Geun Seong,Han, Gui Young,Kim, Sang Done 한국화학공학회 1984 Korean Journal of Chemical Engineering Vol.1 No.1

Kinetics Studies on the Hydrolysis of N-Benzoyl-4,5-diphenylimidazole Derivatives

Lee, Jong-Pal,Lim, Gui-Taek,Lee, Yong-Hee,Lee, Sung-Sik,Koo, In-Sun,Ryu, Zoon-Ha Korean Chemical Society 2003 Bulletin of the Korean Chemical Society Vol.24 No.9

Life Science : Anti-Amyloidogenic Effect of Thiacremonone through Anti-Inflamation in Vitro and In Vivo Models

( Gui Hua Lim ),( Young Jung Lee ),( Dong Young Choi ),( Sang Bae Han ),( Jae Kyung Jung ),( Bang Yeon Hwang ),( Dong Chul Moon ),( Young Soo Kim ),( Myung Koo Lee ),( Ki Wanoh ),( Heon Sang Jeong ),( 영남대학교 약품개발연구소 2012 영남대학교 약품개발연구소 연구업적집 Vol.22 No.0

Neuroinflammation is implicated for amyloidogenesis. Sulfur compounds extracted from garlic have been shown to have anti-inflammatory properties. Previously, we have investigated that thiacremonone, a sulfur compound isolated from garlic has anti-inflammatory effects. To investigate thiacremonone`s potential effect on anti-neuroinflammation and anti-amyloidogenesis, 4 week old ICR mice were given different doses of thiacremonone (1, 3, and 10 mg/kg) in drinking water for 1 month and received intraperitoneal injection of lipopolysaccharide (LPS) (250 μg/kg/day) at last 7 days of treatment. Our data show thiacremonone decreased LPS-induced memory impairment, glial activation, pro-inflammatory mediators` expression, and amyloidogenesis. In an in vitro study, we obtained similar results, with thiacremonone (1, 2, and 5 μg/ml) effectively decreased LPS (1 μg/ml)-induced glial activation and inflammatory mediators generation which are implicated in amyloidogenesis. Our data also demonstrated that thiacremonone inhibited LPS-induced amyloidogenesis in cultured astrocytes and microglial BV-2 cells. NF-κB, a critical transcriptional factor regulating not only inflammation but also amyloid-β generation, was inhibited by thiacremonone via blocking of phosphorylation of IκBα in mice brain as well as cultured astrocytes and microglial BV-2 cells. These results indicated that the anti-inflammatory compound, thiacremonone, inhibited neuroinflammation and amyloidogenesis through inhibition of NF-κB activity, and thus could be applied for intervention of inflammation-related neurodegenerative disease including Alzheimer`s disease.

Purification Characteristics and Hydraulic Conditions in an Artificial Wetland System

( Gui Sook Nam ),( Byeng Hyen Park ),( Jae Ok Kim ),( Kwang Sik Lee ),( Gea Jae Joo ),( Sang Joon Lee ) 한국하천호수학회 2002 생태와 환경 Vol.35 No.4

본 연구는 농업용저수지의 수질개선을 위한 인공습지 시스템에서 수리학적 부하조건과 수질정화 특성간의 상관관계를 평가하고, 습지의 조성과 관리에 관한 기본적이며 주요 인자들을 규명하고자하였다. 인공습지시스템은 저수지 중층수를 유입시키기 위한 양수장과 미나리, 창포, 줄, 부들, 갈대 등의 정수식물을 식재한 6개의 개별습지로 구성되어 있다. 시스템은 자유수면흐름방식으로 유입처리유량 0.012-0.122 ㎥/s, 수리학적 체류시간 0.5-2.0 hr의 수리학적 고부하조건으로 운영하였으며, 수심은 0.1-0.2 m, 유입수질은 저수지를 대상으로 하여 비교적 낮은 영양염류 농도(TN (0.224-2.462 ㎎/L, TP 0.145-0.164㎎/L)를 가지고 있다. 본 연구기간 중 각 개별습지의 평균 수질정화효율은 TN 12.1-14.3%로 갈대조에서 높게 나타났으며, TP는 6.3-9.5%로 식물 종에 따른 큰 차이가 없었다. SS는 17.4-38.5%, Chl-a는 12.6-20.2%로 미나리조에서 높게 나타났는데, 이는 유입수 농도가 다소 높은 때문으로 판단된다. 시간당 정화량은 TN 1.299-2.343g·m^-2 ·d^-1, TP 0.085-1.821g·m^-2 ·d^-1, SS는 17.9-111.6g·m^-2 ·d^-1, Chl-a는 0.011-0.094g·m^-2 ·d^-1로 정화효율에서와 달리 TN은 줄에서 가장 높았고, TP는 창포에서 높았다. 침강성 물질인 SS 와 Chl-a는 미나리에서 높게 나타났으며, 미나리는 BOD, COD, TN, TP 등 다른 수질항목에서도 높은 값을 보여주고 있어 정화효율에서와 같이 유입수농도가 습지내 물질제거에 영향이 있음을 보여준다. 정화효율 및 시간당 정화량과 수리학적 조건간의 상관관계는 수심, 체류시간, 일유입량, 수리학적 부하량, 유입수 농도, 온도 등 다양한 변수에 의한 영향으로 비교적 낮게 나타났다. 정화효율과 수리학적 조건간의 상관계수(R^2)는 수리학적 체류시간과 0.016-0.731, 일처리유량과는 0.015-0.868을 나타내었으며, 시간당 정화량과 수리학적 조건간의 상관계수(R^2)는 수리학적 체류시간과는 0.173-0.763, 일처리유량과는 0.209-0.770의 범위를 나타내었다. 정화효율과 수리학적 부하조건간의 상관계수(R^2)가 0.5 이상을 나타내는 각 수생식물 습지별 수질항목은 체류시간과 일처리유량에 대해 각각 20%, 정화속도와 수리학적 조건간의 상관계수는 체류시간에 대해 53%, 일처리유량에 대해 73%가 0.5 이상을 보이고 있어 시간당 정화량과 수리학적 조건간의 상관관계가 정화효율과의 상관관계보다 좀더 유의성 있게 나타났다. 이것은 높은 수리학적 부하조건이 영양염류 등의 정화효율에는 크게 영향을 미치지 않음을 보여주고 있으며, 따라서 비교적 낮은 농도의 영양염류를 가지고 있고, 많은 처리수량을 요구하는 부영양화된 저수지의 수질개선을 위해서는 높은 수리학적 부하조건에서 시간당 정화량을 늘리는 관리방법이 경제적이며, 이에 초점을 맞추어 나가야 할 것으로 사료된다. he purpose of this study was to evaluate the relationships between purification characteristics and hydraulic conditions, and to clarify the basic and essential factors required to be considered in the construction and management of artificial wetland system for the improvement of reservoir water quality. The artificial wetland system was composed of a pumping station and six sequential plants beds with five species of macrophytes: Oenanthe javanica, Acorus calamus, Zizania latifolia, Typha angustifolia, and Phragmites australis. The system was operated on free surface-flow system, and operation conditions were 3,444-4,166 ㎥/d of inflow rate, 0.5-2.0 hr of HRT, 0.1-0.2 m of water depth, 6.0-9.4 m/d of hydraulic loading, and relatively low nutrients concentration(0.224-2.462 ㎎N/L, 0.145-0.164㎎P/L) of inflow water. The mean purification efficiencies of TN ranged from 12.1% to 14.3% by showing the highest efficiency at the Phragmites australis bed, and these of TP were 6.3-9.5% by showing the similar ranges of efficiencies among all species. The mean purification efficiencies of SS and Chl-a ranged from 17.4% to 38.5% and from 12.6% to 20.2%, respectively, and the Oenanthe javanica bed showed the highest efficiency with higher concentration of influent than others. The mean purification amount per day of each pollutant were 9.8-4.1g·m^-2 ·d^-1 in BOD, 1.299-2.343g·m^-2 ·d^-1 in TN, 0.085-1.821g·m^-2 ·d^-1 in TP, 17.9-111.6g·m^-2 ·d^-1 in SS and 0.011-0.094g·m^-2 ·d^-1 in Chl-a. The purification amount per day of TN revealed the highest level at the Zizania latifolia bed, and TP showed at the Acrous calamus bed. SS and Chl-a, as particulate materials, revealed the highest purification amount per day at the Oenanthe javanica bed that was high on the whole parameters. It was estimated that the purification amount per day was increased with the high concentration of influent and shoot density of macrophytes, as was shown in the purification efficiency. Correlation coefficients between purification efficiencies and hydraulic conditions(HRT and inflow rate) were 0.016-0.731 of R^2 in terms of HRT, and 0.015-0.868 of R^2 daily inflow rate. Correlation coefficients of purification amounts per day with hydraulic conditions were 0.173-0.763 of R^2 in terms of HRT, and 0.209-0.770 daily inflow rate. Among the correlation coefficients between purification efficiency and hydraulic condition, the percentages of over 0.5 range of R^2 were 20% in HRT and in daily inflow rate. However, the percentages of over 0.5 range of correlation were 53% in HRT and 73% in daily inflow rate. The relationships between purification amount per day and hydraulic condition were more significant than those of purification efficiency. In this study, high hydraulic conditions(HRT and inflow rate) are not likely to affect significantly the purification efficiency of nutrient. Therefore, the emphasis should be on the purification amounts per day with high hydraulic loadings(HRT and inflow rate) for the improvement of eutrophic reservoir with relatively low nutrients concentration and large quantity to be treated.

Study on the Onset Bifurcations of a Morris-Lecar Neuron under a Periodic Current

Sang-Gui Lee,김승환 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.50 No.1I

Nervous systems under periodic stimuli display rich dynamical states, including mode-locking and chaotic responses, which have been the subject of intentive studies in neurodynamics. In this paper, the bifurcation structure of a Morris-Lecar neuron under a sinusoidal stimulus is investigated, focusing on the mechanisms of the firing onset with the help of bifurcation and continuation algorithms. This system exhibits a simple bifurcation structure with a bell-shaped firing onset without hysteresis. In particular, at high frequency periodic forcing, an interesting dynamical state with a bursting-like behavior appears This study provides useful insight into the firing onset of various neural systems under periodic forcing.

Distance Relay Suitable for Intertie Protection of a Large Wind Farm

Lee, Sang-Cheol,Lee, Young-Gui,Kang, Hae-Gweon,Zheng, Tai-Ying,Kang, Yong-Cheol The Korean Institute of Electrical Engineers 2012 The Journal of International Council on Electrical Vol.2 No.3

A large modern wind farm should keep connected to the grid in the case of a grid fault whilst it should be isolated for an intertie fault. To achieve this function, this paper proposes a distance relaying algorithm suitable for intertie protection of a wind farm in the time domain. The proposed algorithm estimates impedance based on a differential equation method because the frequencies of the voltage and the current deviate from the nominal frequency. To discriminate an intertie fault from a grid fault, the algorithm uses a voltage blocking scheme because the magnitude of the voltage at the point of common coupling for an intertie fault becomes less than that for a grid fault. The performance of the algorithm is verified using the PSCAD/EMTDC simulator under various fault conditions. The results indicate that the algorithm can extend the reach of Zone 1 up to 100% of the length of an intertie and thus discriminate successfully the intertie fault from the grid fault.

Parameter Dependence of a Bona-Fide Stochastic Resonance in a Stochastic FitzHugh-Nagumo Neuron

Lee Sang-Gui,Kim Seunghwan 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.49 No.1

Recently, an alternative stochastic resonance (SR) condition, called the bona-fide SR, was proposed for a bistable system based on the notions of a residence time distribution, and the existence and the structure of optimal resonant frequencies with maximal resonances at a given noise intensity are investigated actively in various systems. In this paper, the bona-fide stochastic resonance is studied in the stochastic FitzHugh-Nagumo neuron, focusing on the dependence of optimal resonant frequencies on the noise intensity, especially, at small noise intensity. Interestingly, the resonant frequencies become non-zero constant values when the noise intensity becomes very small, which is qualitatively different from the bistable system where the resonant frequency goes to zero at small noise intensity. In fact, these nonzero resonant frequencies corresponding to forcing frequencies with minimal amplitudes in the mode-locking states of the deterministic condition, and this correspondency is discussed with the notion of a noise-induced transition. The contours of the order parameters also show functional shape that are very similar to the phase boundaries of modelocking states. These observations provide a clear relationship between the bona-fide SR and the phase boundaries of mode-locking states.

Nontrivial Critical Behavior of Lattice Models with a Conserved Field on a Checkerboard Fractal

Sang-Gui Lee,이상법 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.-

The conserved lattice gas (CLG) model and the conserved threshold transfer process (CTTP) are known to belong to the same universality class for the dimensionality d ≥ 2, while in one dimension the two models exhibit a universality split. The different hopping mechanisms for the two models due to the dimensional reduction were conjectured to be the source of such a universality split. We here present a ``restricted'' CTTP (RCTTP) model, for which the two active particles on each active site are constrained to interact repulsively and hop to different sites. With this restriction, hopping of active particles is deterministic in one dimension and is dominantly deterministic on a checkerboard fractal. We carry out numerical simulations for the CLG, CTTP and RCTTP models on a checkerboard fractal. We find that the three models exhibit distinct critical behaviors, indicating that the universality split occurs on a checkerboard fractal. We also carry out simulations for the RCTTP model on a square lattice and find that the RCTTP model exhibits the same critical behavior as that of the CTTP model. Such a universality split on a checkerboard fractal appears to be attributed to dominant deterministic hopping for the CLG model and the RCTTP model.

Investigation of harmful bacteria contamination in agricultural water and characterization of Isolated Strains

Gui-Nam Wee,Eun-Sun Lyou,Min-Sung Kim,Tae-Kwon Lee,In-Jun Hwang 대한환경공학회 2019 대한환경공학회 학술발표논문집 Vol.2019 No.12

The role of CD24 in epithelial tumor of the gastrointestinal track

Sung-Chul Lim · Gui-Ae Jeong · Yong Lee · Jung-Eun Chio · Duong Hong Quan 조선대학교 의학연구원 2006 The Medical Journal of Chosun University Vol.31 No.1

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