• Title/Summary/Keyword: Gyu-Dong Choi

Search Result 605, Processing Time 0.032 seconds

In Vivo Antipyretic, Analgesic, and Anti-inflammatory Activities of the Brown Alga Ecklonia cava Extracts in Mice

  • Kang, Ji-Young;Choi, Jae-Suk;Park, Nam-Gyu;Ahn, Dong-Hyun;Hong, Yong-Ki
    • Fisheries and Aquatic Sciences
    • /
    • v.15 no.1
    • /
    • pp.73-76
    • /
    • 2012
  • Dichloromethane, ethanol, and boiling water extracts of the brown alga Ecklonia cava were examined in vivo for their antipyretic, analgesic, and anti-inflammatory activities in mice. These activities were evaluated by yeast-induced pyrexia, tail-flick test, and phorbol myristate acetate-induced inflammation (edema, erythema, and blood flow). Ethanol extract of E. cava (0.4 mg/ear) inhibited the inflammatory symptoms of mouse ear edema, erythema, and blood flow by 82.6%, 69.0%, and 65.4%, respectively. This extract also demonstrated potent analgesic activity. No acute toxicity was observed after p.o. administration of each extract (5 g/kg bw). These in vivo data are in agreement with the claims of the health care industry and indigenous medicine that E. cava is an effective remedy for inflammation-related symptoms.

Design, Synthesis and Anticonvulsive Activities of Potential Prodrugs Linked by Two-carbon Chain

  • Zhao, Long-Xuan;Moon, Yoon-Soo;Basnet, Ar-Jun;Park, Jae-Gyu;Kim, Eun-kyung;Kim, Dae-Ok;Jeong, Tae-Cheon;Jahng, Yurng-Dong;Choi, Jong-Won;Lee, Eung-Seok
    • Archives of Pharmacal Research
    • /
    • v.26 no.10
    • /
    • pp.785-795
    • /
    • 2003
  • For the development of new anticonvulsive agents, GABAmimetics such as nipecotic acid, isonipecotic acid, ${\gamma}-aminobutyric$ acid (GABA), ${\gamma}-vinyl$ GABA (vigabatrin) and valproic acid were covalently coupled through an ester bond by a two-carbon linker chain as potential prodrugs and evaluated for their anticonvulsive activities.

An experimental Study for the Maximun Curing Temperature Effect on the Freezing and Thawing of Steam Curing Concrete (증기양생콘크리트의 최고양생온도변화가 콘크리트의 동결융해저항성에 미치는 영향)

  • Youn, Suk;Choi, Se-Gyu;Kim, Dong-Sin;Yu, Sung-Yong;Kim, Saeng-Bin
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 1997.04a
    • /
    • pp.170-176
    • /
    • 1997
  • The published works on steam curing effect have been generally concentrated on the subject, "compressive strength". However a practical test for durable steam curing concrete products has not been performed in domestic. In this study, the maximum temperature of steam is considered as a major variable to investigate the freezing and thawing resistance of the steam curing concrete. All of the specimen were cured for 24 hours which included presteaming 4 hour. Finally we found that the most effective curing condition is the case of one-day and 14-day specimens after the 24 hours steam curing at $74^{\cire}C$ degree curing temperature. It is also found that the durability of one-day samples are much weaker than those of 14-day samples. Consequently, we can conclude that the samples that produced immediately after a steam curing are more possible to deteriorate from the freezing and thawing environment.vironment.

  • PDF

Lap Splice Strength of Reinforcing Bars on the Relitive Rib Area (상대마디면적에 따른 이형철근의 겹침이음 강도)

  • Park, Sung-Gyu;Hong, Geon-Ho;Choi, Dong-Uk
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2005.05a
    • /
    • pp.307-310
    • /
    • 2005
  • The effects of deformation properties on the bond of steel reinforcing bars to concrete are experimentally studies to expect the lap splice strength. Based on the previous research about relative rib area, lap splice strength between reinforcing bars and concrete can be improved by the control of rib height and spacing. This paper describes the testing and analysis of 15 beam-spliced specimens containing D25, D22, D19 with relative rib areas ranging from 0.066 to 0.162. The tests are analyzed to determine the effect of relative rib area(Rr) on the increase in bond strength. The tests also provide a preliminary indication of the effect of high relative rib area on the splice strength of uncoated bars.

  • PDF

Switch Paralleling Characteristic Analysis for FB Converter in 1[kW] Fuel-Cell System (풀브리지 컨버터를 갖는 1[kW] 연료전지 시스템 스위치 병렬 특성 분석)

  • Choi, Jung-Muk;Han, Dong-Hwa;Lee, Young-Jin;Jeong, Byong-Hwan;Choe, Gyu-Ha
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
    • /
    • v.24 no.9
    • /
    • pp.62-70
    • /
    • 2010
  • Fuel cell system which can solve the environmental problem is receiving attention. To use utility power necessary power conversion system from low voltage that is generated by fuel cell system. because fuel cell has special characteristic of low voltage high current. To improve PCS's efficiency the paralleling method is used. Available the method could reduce the switching loss. But the existing research could not be found optimal result and accompanying several effects. In this study analysis several effects causing the parallel method. The effects have been demonstrated through simulations and experiments.

Digital Controller Design and Implementation of a Bidirectional Battery Charging/Discharging Converter (양방향 배터리 충/방전 컨버터의 디지털 제어기 설계 및 구현)

  • Lee, Young-Jin;Han, Dong-Hwa;Choi, Jung-muk;Cho, Young-hoon;Choe, Gyu-Ha
    • Proceedings of the KIPE Conference
    • /
    • 2013.07a
    • /
    • pp.124-125
    • /
    • 2013
  • 본 논문에서는 배터리 충/방전을 위한 3상 인터리브드 양방향 DC-DC 컨버터의 디지털 전류제어기를 설계 및 구현한다. 기존의 아날로그 제어기와 달리 디지털 PWM 지연과 제어기 연산시간 지연에 대한 현상을 고려한 디지털 전류제어기를 설계하고 배터리 충방전 시스템에 적용하여 타당성을 검증한다.

  • PDF

The Study of PV-BESS System with Active Power Filter Function (Active Power Filter기능을 가지는 PV-BESS시스템 연구)

  • Han, Dong-hwa;Choi, Jung-muk;Lee, Young-Jin;Cho, Young-hoon;Choe, Gyu-ha
    • Proceedings of the KIPE Conference
    • /
    • 2013.07a
    • /
    • pp.479-480
    • /
    • 2013
  • 기존의 태양광 시스템은 일사량이 존재할 경우 즉 태양이 있을경우에만 동작하는 낮은 활용도를 가진다. 본 논문에서는 태양광에서 발전되는 불규칙적인 에너지를 효과적으로 사용하기 위해 BESS 시스템을 결합하여 태양광 시스템의 활용도를 높이며, 계통의 전원의 안정화를 위하여 Active Power Filter기능을 수행한다. 논문에서는 이를 구현하고 타당성을 검증하였다.

  • PDF

A Study on Control System Of Induction Heating (유도 가열기의 제어시스템에 관한 연구)

  • Kim, Dong-Un;Sung, Nark-Kuy;Han, Kyung-Hee;Choi, Gi-Soo;Ahn, Gyu-Bok;Lee, Seung-Hwan
    • Proceedings of the KIEE Conference
    • /
    • 2000.07b
    • /
    • pp.1254-1256
    • /
    • 2000
  • In this paper, a control scheme for induction heating is proposed. The propose scheme estimates, resonant frequency by PI control subbing a phase of output voltage and resonant capacitor voltage. There are would be two advantages in the proposed system over existing induction heating system. One is the rapid resonant frequency estimation. A other is the just control of temperature. Power Circuit is used a inverter stack and transformer rated on 5.5kw.

  • PDF

Fuzzy control system tuning by performance evaluation (성능평가에 의한 퍼지제어시스템 동조)

  • Jeong, Heon;Jeong, Chang-Gyu;Ko, Nack-Yong;Kim, Young-Dong;Choi, Han-Soo
    • Proceedings of the KIEE Conference
    • /
    • 1995.07b
    • /
    • pp.682-684
    • /
    • 1995
  • The most effective way to improve the performance of a fuzzy controller may be to optimize look-up values. Look-up values are derived from processes used input-output scale factors, membership functions, rule base, fuzzy inference method and defuzzification. It is powerful way to modify or organize look-up table values. In this paper, We propose the look-up values self-organizing fuzzy controller(LSOFC). We use the plus-minus tuning method(PMTM), scanning values through the processes of addition and subtraction. We show the efficiency of this LSOFC by the results of simulation for nonlinear time-varying plant with unmodelled dynamics.

  • PDF

Study on Combustion Stability of Sub-scale Gas Generator (축소형 가스발생기 연소안정성 연구)

  • Ahn, Kyu-Bok;Kang, Dong-Hyuk;Kim, Mun-Ki;Lim, Byoung-Jik;Kim, Jong-Gyu;Seo, Seong-Hyeon;Choi, Hwan-Seok
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • 2010.11a
    • /
    • pp.594-596
    • /
    • 2010
  • Hot-firing tests were performed on a sub-scale gas generator for development of a 75 ton-class liquid rocket engine. This paper deals with the analysis results of low-frequency combustion instability that encountered during combustion tests of the gas generator.

  • PDF