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낙동강 남조류에서 Microcystin의 정제와 생화학적 특성
곽충근,정인철,조무연 고신대학교 의학부 1998 高神大學校 醫學部 論文集 Vol.13 No.1-2
The sample were obtained in July and August 1996 from fresh bloom materials composed predominantly of Microcystis spp. The bule-green algae samples was identified to be a Microcystis aeruginosu. The algae samples were harvested, lyophilized, and purification of the microcystin-type toxin were carried out by using Ultrogel AcA 202 column (elution solvent : 20% methanol, flow rate : 0.6ml/min, detector wavelength 238nm)LC. Qualitative analysis was detected to be a microcystin-type toxin. A peak shape and elution time of amino acid analyzer chromatogram of a puried material were identical to those of physiological fluid standard. The amino acid analysis of the physiological fluid standard and the purified field sample did exhibit five amino acid in common, and the same elution time. Presumably, the toxin was identified to be a microcystin-LR type toxin, closely related to microcystin-LR. LC_(50) value of the microcystin-LR type toxin was in the range from 0.4 to 0.8mg dry weight/ml by human lymphoblast NC-37 cel toxicity test. To investigate genomic change in c-myc gene by a hepatotoxin microcystin-LR, human lymphoblast NC-37 cells exposed with microcystin (0.8mg dried cell/ml) was evaluated by the methods of quantitative polymerase chain reaction. When the DNA isolated from NC-37 cells exposed to 0.8mg dried cell/ml of microcystin were amplified by polymerase chain reaction using a primer containing c-myc exon 11, the resulting DNA was appeared to be decrease in microcystin treated cells than in the microcystin untreated control groups. However, the RNA expression in Northern blot hybridization was identical in the control, microcystin treated cells. These results indicate that mi crocystin induces changes in the exon Ⅱ in human c-myc gene, may lead to a transformation of the cell.
배전계통에서 접지망 형태에 따른 과도접지임피던스 모델링에 관한 연구
곽충근,한병길,김경화,김지명,노대석 한국산학기술학회 2022 한국산학기술학회논문지 Vol.23 No.6
최근, 고도 정보화 시대의 급속한 발전과 신재생에너지원의 전력계통 유입의 증가로, 배전계통에서 낙뢰 및 서지 등의 피해에 대비한 피뢰·접지시스템에 대한 연구가 활발히 진행되고 있다. 60Hz 대역의 상용전원 계통 고장사고의 관점에서, 지락 또는 단락사고 시 인체의 감전사고 예방 및 설비보호 측면만을 고려하여 운용되어 왔으나, 다양한 분산형 전원이 연계된 국내 22.9kV-Y 다중 직접접지 배전계통의 접지개념을 상용주파수뿐만 아니라 고주파 대역에서의 접지임피던스를 해석하기 위한 방안이 요구되고 있다. 따라서, 본 논문에서는 전력계통 상용 해석프로그램인 PSCAD/EMTDC를 이용하여, 접지망형태에 따른 과도접지임피던스를 평가할 수 있는 과도접지임피던스의 모델링을 제시하며, 이 모델링은 배전계통부, 수용가부, 뇌서지 발생장치부, 과도접지임피던스 계측부로 구성된다. 또한, 본 모델링을 바탕으로 배전계통의 접지망 형태에 따른 과도접지임피던스의 특성을 분석한 결과, 25kHz 및 1MHz의 과도접지임피던의 최대값은 배전용변전소에서 각각 14.1[Ω], 35.5[Ω]이고, 배전선로 인출점에서 11.3[Ω], 32.6[Ω]이며, 수용가 부하에서 3.15[Ω], 3.2[Ω]으로 산정됨을 알 수 있다. 따라서, 동일한 뇌서지가 발생할 경우에도 주파수 영역(25kHz 및 1MHz)에 따라 과도접지 임피던스가 다르게 나타남을 알 수 있다. Recently, a multitude of research on lightning protection and electrical grounding in the case of an electrical power distribution system has been actively conducted worldwide. In particular, these research activities improve the prevention of the electrical power distribution system's damage from lightning, power surge (due to the rapidly developing advanced information devices and renewable energy resources' interconnections in this system), etc. However, the existing lightning protection and electrical grounding in an electrical power distribution system under 60 Hz bandwidth have been only preventing electrical shocks to humans and protecting this system from grounding and short circuit faults. Hence, analyzing the multi-direct grounding under the reference and high-frequency bandwidths in the case of a 22.9 kV - Y electrical power distribution system connected to various distributed electrical power sources is needed. Therefore, this research evaluated the transient electrical grounding impedance under different electrical grounding types by using the PSCAD/EMTDC software. In particular, this evaluation used a model that had the details of the electrical power distribution system, the customer's electrical load on this system, a lightning surge device, and a device for the transient electrical grounding impedance's measurement. Notably, this evaluation showed that the transient electrical grounding impedance's characteristics depended on the electrical power distribution system's frequency bandwidth, such as 25 kHz or 1 MHz.
낙동강 남조류에서 Microcystin의 경제와 생화학적 특성
곽충근,정인철,조무연 고신대학교(의대) 고신대학교 의과대학 학술지 1998 고신대학교 의과대학 학술지 Vol.13 No.1
The sample were obtained in July and August 1996 from fresh bloom materials composed predominantly of Microcystis spp. The blue-green algae samples was identified to be a Microcystis aeruginosa. The algae samples were harvested, lyophilized and purification of the microcystin-type toxin were carried out by using Ultrogel AcA 202 column (elution solvent : 20% methanol, flow rate : 0.6ml/min, detector wavelength : 238nm) LC. Qualitative analysis was detected to be a microcystin-type toxin. A peak shape and elution time of amino acid analyzer chromatogram of a purified material were identical to those of physiological fluid standard. The amino acid analysis of the physiological fluid standard and the purified field sample did exhibit five amino acid in common, and the same elution time. Presumably, the toxin was identified to be a microcystin-LR type toxin, closely related to microcystin-LR. LC50 value of the microcystin-LR type toxin was in the range from 0.4 to 0.8mg dry weight/ml by human lymphoblast NC-37 cell toxicity test. To investigate genomic change in c-myc gene by a hepatotoxin microcystin-LR, human lymphoblast NC-37 cells exposed with microcystin (0.8mg dried cell/ml) was evaluated by the methods of quantitative polymerase chain reaction. When the DNA isolated from NC-37 cells exposed to 0.8mg dried cell/ml of microcystin were amplified by polymerase chain reaction using a primer containing c-myc exon II, the resulting DNA was appeared to be decrease in microcystin treated cells than in the microcysin untreated control groups. However, the RNA expression in Northern blot hybridization was identical in the control, microcystin treated cells. These results indicate that microcystin induces changes in the exon II in human c-myc gene, may lead to a transformation of the cell.
배전계통에서 접지망 형태에 따른 과도접지 임피던스 평가 알고리즘에 관한 연구
곽충근,김경화,김지명,최성문,김윤호,노대석 대한전기학회 2024 전기학회논문지 Vol.73 No.7
Recently, the researches on lightning and surge protection system are being actively conducted due to development of the information technology and large scale interconnection of renewable energy sources in power distribution system. Because the exsiting methods have dealt with prevention of human electric shock and equipment protection only considering reference frequency when the faults such as grounding and short-circuit are occurred, operation method of grounding impedance considering both reference and transient frequencies is being required. Therefore, this paper presents a calculation method of transient grounding impedance in rods and mesh grounding types to evaluate the transient grounding impedance in high frequency bandwidth, and proposes an evaluation algorithm to reduce the transient grounding impedance. Where, the proposed algorithm calculates grounding impedance in both reference and transient frequencies, and designs proper configuration of rods and mesh grounding types in order to meet the code of KEC. And also, this paper performs the modeling which is composed of distribution system, PV system and detecting device of transient grounding impedance using PSCAD/EMTDC S/W. From the simulation results based on the evaluation algorithm and modeling, it is confirmed that the proposed algorithm is useful tool to maintain the transient impedance and surge current within the allowable limit in KEC code.
배전계통에서 접지망 형태에 따른 과도접지임피던스 모델링에 관한 연구
곽충근(Ghung-Geun Kwak),한병길(Byeong-Gil Han),최익준(Ik-Joon Choi),이명근(Myung-Geun Lee),노대석(Dae-Seok Rho) 대한전기학회 2021 대한전기학회 학술대회 논문집 Vol.2021 No.10
배전계통에서 주로 사용하는 접지망은 접지동봉과 메쉬접지 방식을 채택하여 시공하는데, 접지망 형태에 따라 과도접지임피던스의 특성이 달라지기 때문에, 낙뢰 및 서지 등의 피해가 발생할 수 있다. 따라서, 본 논문에서는 전력계통 상용 해석프로그램인 PSCAD/ EMTDC를 이용하여, 모의 배전선로부와 수용가 부하, 뇌서지 발생장치부, 과도접지임피던스 검출부로 구성된 접지망 형태에 따른 과도접지임피던스 모델링을 제시한다. 이 모델링을 바탕으로 과도접지임피던스의 특성을 분석한 결과, 25[kHz]와 1[MHz]의 뇌서지가 발생한 경우, 접지망 형태에 따라 과도접지 임피던스의 특성이 다르게 나타남을 알 수 있었다.