고수두 1,000 MW 석탄화력발전소 냉각수계통 수격방지장치의 성능특성

김근필,유호선,Kim, Keun-Pil,Yoo, Hoseon 한국플랜트학회 2019 플랜트 저널 Vol.15 No.4

In recent, according to the tightening of environment regulation policy, the height of the site of the power plant is increased and the length of the cooling water pipe is increased. This has a serious impact on the stability of the plant. This study analyzes the transient phenomenon using LIQT 7.2, an unsteady state one-dimensional analysis software, to secure the stability of 1,000 MW high-capacity coal-fired power plant cooling water system with high head. To prevent water hammer, The effects on performance characteristics were predicted by individual and combination application. The surge pressure of the cooling water which occurs when the pump was stopped without installing the anti-surge devices was the largest at the pump outlet side. The most effective and simple way to reduce surge pressure in these cooling water systems is to combine a vacuum breaker with a hydraulic non-return valve, which is an essential device for pump protection. 최근 환경 규제 정책 강화에 따른 입지 제약발생으로 발전소 부지가 높아지고 냉각수 관로의 길이가 증가되어 냉각수 계통 내 수격현상이 심화된다. 이는 발전소 안정성에 심각한 영향을 주게 된다. 본 연구에서는 수두가 높은 1,000 MW급 대용량 석탄화력발전소 냉각수계통에 대한 안정성을 확보하고자 비정상상태 1차원 해석 상용 소프트웨어인 LIQT 7.2을 사용하여 과도현상을 분석하고, 수격현상을 저감하기 위해 수격방지장치를 개별 및 조합 적용하여 성능특성에 대한 효과를 예측하였다. 수격방지 장치를 설치하지 않고 펌프가 불시 정지되었을 경우 발생하는 냉각수 서지압력은 펌프 출구 측에서 가장 크게 나타났다. 이러한 냉각수계통의 서지압력을 저감시키는 가장 효과적이고 간단한 방법은 펌프 보호를 위해 필수적 장치인 유압구동역류방지밸브에 진공파괴밸브를 조합한 것이다.

Hop2 and Sae3 Are Required for Dmc1-Mediated Double-Strand Break Repair via Homolog Bias during Meiosis

조홍래,김근필,공윤주,홍수길 한국분자세포생물학회 2016 Molecules and cells Vol.39 No.7

During meiosis, exchange of DNA segments occurs be-tween paired homologous chromosomes in order to pro-duce recombinant chromosomes, helping to increase genetic diversity within a species. This genetic exchange process is tightly controlled by the eukaryotic RecA homologs Rad51 and Dmc1, which are involved in strand exchange of meiotic recombination, with Rad51 participating specifically in mitotic recombination. Meiotic recombination requires an interaction between homologous chromosomes to repair programmed double-strand breaks (DSBs). In this study, we investigated the budding yeast meiosis-specific proteins Hop2 and Sae3, which function in the Dmc1-dependent pathway. This pathway mediates the homology searching and strand invasion processes. Mek1 kinase participates in switching meiotic recombination from sister bias to homolog bias after DSB formation. In the absence of Hop2 and Sae3, DSBs were produced normally, but showed defects in the DSB-to-single-end invasion transition mediated by Dmc1 and auxiliary factors, and mutant strains failed to complete proper chromosome segregation. However, in the absence of Mek1 kinase activity, Rad51-dependent recombination progressed via sister bias in the hop2 or sae3 mutants, even in the presence of Dmc1. Thus, Hop2 and Sae3 actively modulate Dmc1-dependent recombination, effectively progressing homolog bias, a process requiring Mek1 kinase activation.

Shu1 Promotes Homolog Bias of Meiotic Recombination in Saccharomyces cerevisiae

홍수길,김근필 한국분자세포생물학회 2013 Molecules and cells Vol.36 No.5

Homologous recombination occurs closely between ho-mologous chromatids with highly ordered recombino-somes through RecA homologs and mediators. The present study demonstrates this relationship during the period of “partner choice” in yeast meiotic recombination. We have examined the formation of recombination intermediates in the absence or presence of Shu1, a member of the PCSS complex, which also includes Psy3, Csm2, and Shu2. DNA physical analysis indicates that Shu1 is essential for promoting the establishment of homolog bias during meiotic homologous recombination, and the partner choice is switched by Mek1 kinase activity. Furthermore, Shu1 pro-motes both crossover (CO) and non-crossover (NCO) pathways of meiotic recombination. The inactivation of Mek1 kinase allows for meiotic recombination to progress efficiently, but is lost in homolog bias where most double-strand breaks (DSBs) are repaired via stable intersister joint molecules. Moreover, the Srs2 helicase deletion cells in the budding yeast show slightly reduced COs and NCOs, and Shu1 promotes homolog bias inde-pendent of Srs2. Our findings reveal that Shu1 and Mek1 kinase activity have biochemically distinct roles in partner choice, which in turn enhances the understanding of the mechanism associated with the precondition for homolog bias.

NtHSP70-2 and NtHSP17.6 from Nicotiana tabacum Could Function Together in Chaperone Network

윤해정,김근필,박수민,홍주봉 한국유전학회 2006 Genes & Genomics Vol.28 No.2

Heat shock protein 70 (HSP70) is a highly conserved protein family that shows molecular chaperone activity in protecting proteins from aggregation and folding of polypeptides. Small heat shock proteins (sHSPs) that are abundant in plants under abiotic stress conditions are also known to function as molecular chaperones, however, active function of sHSPs in refolding their substrates has not been detected in plants. Thus, possible composite function of sHSPs with other molecular chaperones has been suggested and, in many cases, proven. NtHSP70-2, a HSP70 from Nicotiana tabacum, was overexpressed and purified from Escherichia coli. Firstly, purified NtHSP70-2 was examined for its chaperone activity in vitro and was confirmed as a typical and strong molecular chaperone. Then composite function of NtHSP70-2 and NtHSP17.6, a cytosolic sHSP from N. tabacum, was tested for the activity to refold firefly luciferase in vitro. Luciferase refolding assay showed that luciferase associated with NtHSP17.6 could be reactivated by the components of rabbit reticulocyte lysate and the activity of reticulocyte lysate was proportional to the concentration of NtHSP17.6. NtHSP70-2 could not replace the reticulocyte lysate but dramatically enhanced refolding of luciferase. These data suggest that NtHSP70-2 and NtHSP17.6 function together to refold heat-denatured substrates with the help of other chaperones.

기업특성요인이 회계이익의 정보효과에 미치는 영향에 관한 연구

정용근,김근필 동국대학교 경영대학원 1999 經營論叢-東國大學校 經營大學院 Vol.23 No.-

택지개발사업지구의 단독주택용지 토지이용실태와 범죄발생에 관한 연구 -지방중소도시 노후주거지를 대상으로-

김민혜,최상철,김근필,채병선 전북대학교 부설 휴양및경관계획연구소 2019 휴양및경관연구 (J East Asian Landscape Studies) Vol.13 No.3

This study is proceeded on basis of the hypothesis that the detached housing area created by the housing site development project ‘will increase in crime due to the deterioration of the housing environment such as the deterioration with housing and mixed-use of land, the spread of non-residential facilities, and the increase of vacancy (empty houses).’ Targeting the detached housing areas created more than 27 years ago, this study compares and analyzes the researched materials of land-use status in 1996, and analyzes and considers the relationship between housing environment and violence and theft crime occurrence (2006-2018). As a result, first, non-residential facilities more than doubled in 2016 compared to 1996, spreading into inner parts of residences bordering the collector street in the districts, and the rate of working and religious spaces and vacancy increased. Second, the incidence rate of violent crimes was high in the local distribution road where through traffics took place and in sites with mixed uses bordering the collector street. And violent crimes intensively occurred in areas concentrated in liquor sales facilities among the Type2 neighborhood living facility. Third, the intrusion theft crime rate was higher among theft crimes, and the incidence rate was higher in residential buildings (60.3%) than in non-residential buildings (39.7%). Fourth, the crime rate in buildings with a vacancy was not high, but crimes repeatedly occurred in adjacent buildings with vacancies located in the street and roads. The results of this analysis may be used to promote the CPTED project through the cooperation of the residents, the administration, and the police in order to improve the residential environment in the old residential area, and reflected on the vertical and lot system plan and the district unit plan that will enable to secure ‘safety’ for creating the detached housing site in the future. 본 연구는 택지개발사업으로 조성된 단독주택용지가 ‘주택의 노후화와 토지이용의 혼재, 비주거시설의 확산, 공실(빈집) 증가 등으로 주거환경이 악화됨에 따라 범죄가 증가할 것이다’라는 가설 아래 진행되었다. 조성된 지 27년이 지난 단독주택용지를 대상으로 1996년 토지이용실태에 관한 연구 자료와 비교·분석하고, 주거환경과 폭력·절도범죄 발생(2006~2018년)과의 관계를 분석․고찰하였다. 연구 결과, 첫째, 1996년에 비해 2016년 비주거시설이 2배 이상 증가하며 지구 내 집산도로에 접한 주거지 내부로 확산되었고, 업무와 종교, 공실의 비율이 증가하였다. 둘째, 폭력범죄는 통과교통이 발생하는 보조간선과 집산도로에 접한 용도혼재 필지에서 발생비율이 높았고, 제2종근린생활시설 중 주류 판매시설이 밀집한 곳에서 집중되어 발생하였다. 셋째, 절도범죄 중 침입절도범죄율이 높게 나타났고 비주거건축물(39.7%) 보다 주거건축물(60.3%)에서 발생률이 높았다. 넷째, 공실이 있는 건축물에서의 범죄율은 높지 않지만, 공실이 입지한 가로의 인접 건축물과 노상에서 중복적으로 범죄가 발생되었다. 이러한 분석결과는 노후주거지의 주거환경 향상을 위해 주민과 행정 및 경찰이 협력하여 CPTED 사업 추진에 활용할 수 있고, 향후 단독주택용지를 조성함에 있어 ‘안전성’을 확보할 수 있는 가로 및 필지체계 계획과 지구단위계획에 반영할 수 있다.

In situ Imaging of Meiotic Chromosomes Dynamic of Trapped Yeast Cells by using Microfluidic chip

장성찬,정헌호,김근필,이창수 한국공업화학회 2013 한국공업화학회 연구논문 초록집 Vol.2013 No.1

효모 감수분열과정에서의 유전자 재조합 기전 특이적 DNA 중간체의 구조 변화

성영진,윤상욱,김근필,Sung, Young Jin,Yoon, Sang Wook,Kim, Keun Pil 한국미생물학회 2013 미생물학회지 Vol.49 No.1

유전자 재조합체는 상동염색체간의 예정된 DNA 가닥 전이와 교환이 이루어지는 상동염색체 재조합 과정에 의하여 생성된다. 이 재조합 경로는 DNA 이중 가닥 절단(double-strand breaks, DSBs)에 의해서 개시되며, 전이 과정의 중간단계에서 DNA의 구조적 변이 중간체인 단일 가닥 침투(single-end invasions, SEIs)와 이중 홀리데이 접합(double-Holliday junctions, dHJs)이 형성되어 교차성(crossover, CO) 혹은 비교차성(non-crossover, NCO) 결과물이 만들어진다. 본 연구는 이중 가닥 절단, 단일 가닥 침투, 이중 홀리데이 접합과 같은 재조합 중간체와 재조합 결과물의 구조분석에 초점을 두고, 이를 출아효모에서 인위적으로 이중 가닥 절단을 발생시킬 수 있는 HIS4LEU2 "hot spot" 을 이용한 물리적 분석방법으로 감수분열 재조합 중간체를 규명하였다. 물리적 분석을 위하여 동조화 된 세포에 감수분열을 유도한 후 hot spot 자리를 인식하는 제한효소를 처리하면, 재조합 중간체를 형성하고 있는 DNA 단편들을 Southern 분석법을 통해 탐지 및 정량 할 수 있다. 본 연구는 이 시스템으로 감수분열에서 이중가닥 절단으로부터 기인하는 단일 가닥 침투, 이중 홀리데이 접합 그리고 교차성/비교차성 재조합체로 전이되는 DNA의 구조 다형을 분석할 수 있음을 제시한다. During meiosis, genetic recombinants are formed by homologous recombination accompanying with the programmed double-strand breaks (DSBs) and strand exchanges between homologous chromosomes. The mechanism is generated by recombination intermediates such as single-end invasions (SEIs) and double-Holliday junctions (dHJs), and followed by crossover (CO) or non-crossover (NCO) products. Our study was focused on the analysis of meiotic recombination intermediates (DSBs, SEIs, and dHJs) and final recombination products (CO and NCO). We identified these meiotic recombination intermediates using DNA physical analysis under HIS4LEU2 "hot spot" system in budding yeast, Saccharomyces cerevisiae. For DNA physical analysis, when the hot spot locus is recognized by restriction enzyme from synchronous meiotic cells, the fragmented DNA that are forming recombination intermediates can be detected and quantified through Southern hybridization analysis. Our study suggests that this system can analyze the structural change of recombination intermediates during DSB-SEI transition, double-Holiday junctions and crossover/non-crossover products in meiosis.

Cellular Dynamics of Rad51 and Rad54 in Response to Postreplicative Stress and DNA Damage in HeLa Cells

최의환,윤서빈,한윤수,김근필 한국분자세포생물학회 2017 Molecules and cells Vol.40 No.2

Homologous recombination (HR) is necessary for maintenance of genomic integrity and prevention of various mutations in tumor suppressor genes and proto-oncogenes. Rad51 and Rad54 are key HR factors that cope with replication stress and DNA breaks in eukaryotes. Rad51 binds to single-stranded DNA (ssDNA) to form the presynaptic filament that promotes a homology search and DNA strand exchange, and Rad54 stimulates the strand-pairing function of Rad51. Here, we studied the molecular dynamics of Rad51 and Rad54 during the cell cycle of HeLa cells. These cells constitutively express Rad51 and Rad54 throughout the entire cell cycle, and the formation of foci immediately increased in response to various types of DNA damage and replication stress, except for caffeine, which suppressed the Rad51-dependent HR pathway. Depletion of Rad51 caused severe defects in re-sponse to postreplicative stress. Accordingly, HeLa cells were arrested at the G2–M transition although a small amount of Rad51 was steadily maintained in HeLa cells. Our results suggest that cell cycle progression and proliferation of HeLa cells can be tightly controlled by the abundance of HR proteins, which are essential for the rapid response to postreplicative stress and DNA damage stress.

활선상태의 저항성 누설전류 측정장치 개발

유지하,구윤서,이동준,김근필 대한전기학회 2012 대한전기학회 학술대회 논문집 Vol.2012 No.7