<출판저널> 연중기획 '이달의 책, 이달의 저자' - "물방울 하나 떨어지면" 깊이 읽기

이경철,Lee, Gyeong-Cheol 대한출판문화협회 2004 출판저널 Vol.339 No.-

P-V 곡선법을 활용한 땃두릅나무의 내건성 평가

이경철,권영휴,권윤구,한상균,Lee, K.C.,Kwon, Y.H.,Kwon, Y.K.,Han, S.K. 국립한국농수산대학교 교육개발센터 2019 현장농업연구지 = Journal of practical agricultural resear Vol.21 No.1

This study was carried out to establish a proper cultivation site and to diagnose the drought tolerance of Oplopanax elatus leaves by using pressure-volume curves. As a result of analysing data measured, the leaf of Oplopanax elatus showed the osmotic pressure at full turgor(Ψosat) was -0.77 MPa, and the osmotic pressure at incipient plasmolysis(Ψotlp) was -0.90 MPa. Then, the value of maximum bulk modulus of elasticity Emax was 3.7 MPa, showing that slightly lower drought tolerance of Oplopanax elatus. Furthermore, the values of relative water contents RWCtlp and RWC^* were above 80%, showing that the function of osmoregulation is somewhat better. Thus, responses to water relations such as Ψosat, Ψotlp, Emax, RWCtlp and RWC^* of Oplopanax elatus showed relatively lower drought-tolerance property indicating that those growth are appropriate in high moisture soil sites.

산마늘과 울릉산마늘 유묘의 생장특성 비교

이경철,김하선,한상균,이경민,Lee,K.C.,Kim,H.S.,Han,S.K.,Lee,K.M. 국립한국농수산대학교 교육개발센터 2017 현장농업연구지 = Journal of practical agricultural resear Vol.19 No.1

This study was conducted to investigate of growth performances and net assimilation rate(NAR) of Allium microdictyon Prokh. distributed inland and Allium ochotense Prokh. originated Ulleung-do. The Allium microdictyon on the growth of 1-2 years showed the largest relative growth rate, and showed high relative growth from three to four years. Allium ochotense on the growth from one year to three years showed high relative growth rate. The T/R rate of Allium ochotense of 2~5years was in the range of 0.4~0.5. However, The T/R rate of Allium microdictyon was increased as increasing with age. This implies that Allium microdictyon was consumed more energy on growing subterranean part. The LWR of 1~3years old Allium ochotense. was showed more smaller than 4~5years old. It seems that the growth characteristics of Allium ochotense 1-3 years after sowing the leaf growth consume more energy than Allium microdictyon. Net assimilation rate(NAR) of Allium ochotense for 1-3 years after sowing was higher than that of Allium microdictyon. In this time, the material of Allium ochotense has a higher production efficiency can be seen indirectly.

P-V 곡선법을 활용한 어수리의 수분특성 분석

이경철,권영휴,이경민,한상균,Lee, K.C.,Kwon, Y.H.,Lee, K.M.,Han, S.K. 국립한국농수산대학교 교육개발센터 2017 현장농업연구지 = Journal of practical agricultural resear Vol.19 No.1

This study was carried out to establish a proper cultivation site and to diagnose the drought tolerance of Heracleum moellendorffii leaves by using pressure-volume curves. As a result of analysing data measured, the leaf of H. moellendorffii showed the osmotic pressure at full turgor (Ψ_o^sat) was -1.0MPa, and that at incipient plasmolysis (Ψ_o^tlp) -1.2MPa. Then, the value of maximum bulk modulus of elasticity Emax was 28MPa, showing the sightly strong drought tolerance of H. moellendorffii. Furthermore, the values of relative water contents RWC^tlp and RWC^* were above 88%, showing that the function of osmoregulation is somewhat better. Thus, responses to water relations such as Ψ_o^sat, Ψ_o^tlp, E_max, RWC^tlp and RWC^* of H. moellendorffii showed it's slightly high drought tolerance property.

토양 건조 및 침수처리가 박태기나무의 광계 II 활성에 미치는 영향

이경철,이의열,윤경규,권영휴,한상균,Lee, K.C.,Lee, U.Y.,Youn, K.K.,Kwon, Y.H.,Han, S.K. 국립한국농수산대학교 교육개발센터 2020 현장농업연구지 = Journal of practical agricultural resear Vol.22 No.1

This study was conducted to investigate the photosystem II activities of Cercis chinensis by soil water condition. Drought stress was induced by withholding water and waterlogging treatments was immerging the pots for 15 days. Results showed that the relative activities per reaction center such as ABS/RC, TRo/RC and Dio/RC were significantly increased compared with the control group after 12 days in waterlogging treatments. Particularly, Dio/RC increased substantially under waterlogging stress, indicating that excessive energy was consumed by heat dissipation. Furthermore, the performance index on absorption basis(PI_abs) and responses to structural and functional PS II(SFI_abs) were dramatically decreased after 15 days in both the drought and waterlogging treatments, which reflects the relative reduction state of the photosystem II. These results of chlorophyll a fluorescence by OKJIP analysis show that the sensitive changes photosystem II activity. Thus, on the basis of our results that Cercis chinensis was exhibited a strong reduction of photosynthetic activity to waterlogging stress, and OKJIP parameters such as ABS/RC, DIo/RC, PI_abs and SFI_abs could be useful indicator to monitor the physiological states of Cercis chinensis under soil water condition.

건조스트레스가 수리취의 광합성 및 수분관련 특성에 미치는 영향

이경철,이학봉,Lee, Kyeong-Cheol,Lee, Hak Bong 한국산림과학회 2017 한국산림과학회지 Vol.106 No.3

이 연구는 건조스트레스가 수리취의 생리적 반응에 미치는 영향을 알아보고자 수행하였으며, 건조스트레스는 25일 간의 단수처리를 통해 유도하였다. 건조스트레스가 진행됨에 따라 새벽 녘 수분포텐셜(${\Psi}_{pd}$)과 정오의 수분포텐셜(${\Psi}_{mid}$)이 모두 감소하였으며, 수분불포화도(WSD)는 약 7배 증가하였다. 특히 일중 수분포텐셜차(${\Psi}_{pd}-{\Psi}_{mid}$)는 처리 후 10일까지 0.22~0.18 MPa 범위로 큰 차이를 나타냈으나 이후에는 차이가 크게 줄어드는 경향을 보였다. 수리취는 건조스트레스 처리 후 15일부터 기공전도도와 기공증산속도의 감소가 두드러졌고, 처리 20일 이후에는 최대광합성 속도와 순양자수율 역시 큰 폭으로 감소한 반면 수분이용효율은 반대의 경향을 보였다. 이것은 기공을 통한 $CO_2$와 수분의 조절이 원활하지 못해 광합성량의 감소가 일어난 것을 의미한다. JIP 분석을 통해 단수처리 15일 이후에 기능지수($PI_{ABS}$) 및 에너지전달 효율의 감소가 두드러진 것으로 나타났으며, 광계 2의 활성이 감소한 것을 보여준다. 엽의 원형질 분리시 삼투포텐셜 ${\Psi}_o{^{tlp}}$은 -0.4 MPa, 최대포수시의 삼투포텐셜 ${\Psi}_o{^{sat}}$은 -0.35 MPa의 삼투적 적응 반응을 나타냈으며, 최대탄성계수($E_{max}$)의 탄성적 적응은 9.4 MPa로 나타나 수리취는 건조스트레스에 따라 삼투적 적응과 탄성적 적응이 모두 나타나는 것을 알 수 있었다. Vo/DW, Vt/DW와 같은 수분특성인자는 건조스트레스에 따라 증가되는 것으로 나타났다. 결과적으로 수리취는 새벽녘 엽수분포텐셜이 -0.93 MPa 이하로 저하되면 광합성 활성의 감소가 크게 나타나고, 건조스트레스에 따라 삼투적 적응과 탄성적 적응이 나타나 이것이 이 식물의 중요한 적응방법임을 알 수 있었다. This study was conducted to find out the influence of drought stress on physiological responses of Synurus deltoides. Drought stress was induced by withholding water for 25 days. Leaf water potentials were decreased of both predawn (${\Psi}_{pd}$) and mid-day (${\Psi}_{mid}$) with increasing drought stress, but water saturation dificit (WSD) was 7 times increased. ${\Psi}_{pd}-{\Psi}_{mid}$ showed the significant difference of 0.22~0.18 MPa in stressed before 10 days, and nonsignificant as treatment time became longer. A strong reduction of stomatal conductance ($gH_2O$) and stomatal transpiration rate (E) were observed after 15 days of drought stress Significant reductions of net apparent quantum yield (${\Phi}$) and maximum photosynthesis rate ($Pn_{max}$) were observed after 20 days of drought stress; However, water use efficiency (WUE) was shown the opposite trend. This implies that decrease of photosynthesis rate may be due to an inability to regulate water and $CO_2$ exchanged through the stomata. From JIP analysis, flux ratios (${\Psi}_O$ and ${\Phi}_{EO}$) and performance index on absorption basis ($PI_{ABS}$) were dramatically decreased withholding water after 15 days, which reflects the relative reduction of photosystem II activity. The leaf of S. deltoides showed osmotic adjustment of -0.35 MPa at full turgor and -0.40 MPa at zero turgor, and also cell-wall elastic adjustment of 9.4 MPa, indicating that S. deltoides tolerate drought stress through osmotic adjustment and cell-wall elastic adjustment. The degree of change in water relations parameters such as Vo/DW, Vt/DW decreased with increasing drought stress. This result showed that S. deltoides was exhibited a strong reduction of photosynthetic activity to approximately -0.93 MPa of predawn leaf water potential, and both of osmotic adjustment and cell-wall elastic adjustment in drought stress condition appears to be an important adaptation for restoration in this species.

페라이트계 스테인리스 강 MAG 용접의 기계적 물성에 관한 연구

이경철,김재성,김현재,임경호,이보영,Lee, Gyeong-Cheol,Kim, Jae-Seong,Kim, Hyun-Jae,Lim, Kyoung-Ho,Lee, Bo-Young 대한용접접합학회 2009 대한용접·접합학회지 Vol.27 No.2

Ferritic stainless steels have a good heat resistance and economic advantage. They are used for applications such as automotive exhaust systems where resistance to general corrosion is superior to carbon steels. However, there are not enough research for ferritic stainless steels on weldability mainly used as automotive exhaust manifolds. In this study, mechanical and microstructure properties of as-welded STS 429L and STS 444 ferrite stainless steels were confirmed by tensile, bending, hardness test, optical microscopy and scanning electron microscopy. Tensile strength of the STS 444 is higher than the STS 429L when it is a raw material. In contrast to this fact, STS 429L indicated higher tensile strength after butt welded. In addition, the hardness have a increasing tendency as getting down on the bead.

Mn - Zn 페라이트의 레이저 유도 열화학 습식식각

이경철,이천 ( Kyoung Cheoul Lee,Cheon Lee ) 한국전기전자재료학회 1997 전기전자재료학회논문지 Vol.10 No.7

자궁경부 조직 진단을 기준으로 Surepath$^{TM}$ 액상세포검사와 고식적 직접도말 자궁경부 세포검사법의 비교

이경철,정찬권,정은선,최영진,박종섭,이교영,이아원,Lee, Kyung-Chul,Jung, Chan-Kwon,Jung, Eun-Sun,Choi, Yeong-Jin,Park, Jong-Sup,Lee, Kyo-Young,Lee, Ah-Won 대한세포병리학회 2007 대한세포병리학회지 Vol.18 No.1

This study was performed to compare Surepath$^{TM}$ liquid-based smear and a conventional cervicovaginal smear with reference to a histological diagnosis. A hybrid capture test (HCII) was also performed and analyzed. We collected matched cases for cervicovaginal cytology-histology: 207 cases for conventional cytology (CC) and 199 cases for liquid-based cytology (LBC). HCII was performed in 254 patients. When a cytological diagnosis of ASCUS or above (ASCUS+) is classified as positive and a histological diagnosis of LSIL+ is classified as positive, the sensitivity and specificity for LBC was 91.7% and 75.9%, respectively and the sensitivity and specificity for CC was 62.6% and 96.1%, respectively. When a cytological and histological diagnosis of LSIL+ is classified as positive, the sensitivity and specificity for LBC was 77.5 and 96.6%, respectively and the sensitivity and specificity for CC was 49.7% and 100%, respectively. When a histological diagnosis of LSIL+ is classified as positive, the sensitivity and specificity for HCII was 78.9% and 78.1%, respectively. The concordance ratio between the cytological and histological diagnosis was 80.4% (kappa=76.0) for LBC and 56.5% (kappa=55.1) for CC. LBC is more sensitive and less specific then CC, as a cytological cutoff level of ASCUS, but more sensitive and equally specific, as a cytological cutoff level LSIL or HSIL. LBC is more reliable with a high concordance ratio between the cytological and histological diagnosis.

비행 중 회항 시도 항공기의 비행자료 분석

이경철,이종희,송병흠,신대원,Lee, K.C.,Lee, J.H.,Song, B.H.,Shin, D.W. 한국항공운항학회 2003 한국항공운항학회지 Vol.11 No.1

This study is performed to secure the safety of civil aviation by establishing systematic analysis ability of Flight Data Recorder. Through this study, downloading SSFDR(Solid State Flight Data Recorder) to personal computer, editing interface file, flight data numerical analysis and regulations relayed to the aircraft with carry diversion into execution are performed. In the analysis, the flight data of B747-400 model aircraft between Jeju(RKPC) and Gimpo(RKSS) was selected.