대표농도경로 (RCP) 시나리오에 따른 회야강 유역의 미래 유출 및 유사 변화 분석

황창수(Hwang, Chang Su),최철웅(Choi, Chul Uong),최지선(Choi, Ji Sun) 대한공간정보학회 2014 대한공간정보학회지 Vol.22 No.3

본 연구는 미래 기후변화 및 토지피복변화가 유역 내 유출량과 유사량의 거동에 가져올 영향을 분석하는데 목적이 있다. 기상자료는 IPCC 5차 평가보고서를 위해 새롭게 논의된 RCP 시나리오 중 서로 상반되는 4.5 및 8.5 시나리오의 기후전망 (2011~2100년) 이 사용되었으며, 토지피복지도는 RCP 4.5 및 8.5 시나리오의 사회ㆍ경제 스토리라인과 로지스틱 회귀모형 (LR)을 이용하여 개발 된 모델에 의해 구축되었다. 기후변화만 고려한 경우, 토지피복변화만 고려한 경우, 기후변화 및 토지피복변화 모두 고려한 경우의 세 가지 시나리오를 설정하고, 각 시나리오에 따른 유출량 및 유사량을 모의한 결과 계절적으로 매우 명확한 변화를 나타내었다. 기후변화는 봄과 겨울에 유출량을 증가시키고 여름과 가을에 유출량을 감소시키는 것으로 나타났으며, 유사량 역시 유출량과 동일한 변화의 양상을 보였다. 토지피복변화는 유출량을 증가시키는 반면 유사량은 감소시키며, 이는 도시화로 인한 불투수 면적의 증가에 의한 것으로 판단된다. 토지피복변화는 기후변화에 비해 유출량에 적은 영향을 끼치나, 기후변화에 의해 초래된 유출량 문제를 더욱 극대화 시킬 수 있다. 따라서 지속적인 수자원 관리를 위하여 기후변화의 잠재적 영향을 파악하고, 토지피복변화에 따른 적절한 수자원 대응 정책 마련이 필요할 것으로 판단된다. This study is analyze future climate and land cover change affects behaviors for amount of streamflow and sediment discharge within basin. We used the climate forecast data in RCP 4.5 and 8.5 (2011-2100) which is opposite view for each other among RCP scenarios that are discussed for 5th report for IPCC. Land cover map built based on a socialㆍeconomic storyline in RCP 4.5/8.5 using Logistic Regression model. In this study we set three scenarios: one scenario for climate change only, one for land cover change only, one for Last both climate change and land cover change. It simulated amount of streamflow and sediment discharge and the result showed a very definite change in the seasonal variation both of them. For climate change, spring and winter increased the amount of streamflow while summer and fall decreased them. Sediment showed the same pattern of change steamflow. Land cover change increases the amount of streamflow while it decreases the amount of sediment discharge, which is believed to be caused by increase of impervious Surface due to urbanization. Although land cover change less affects the amount of streamflow than climate change, it may maximize problems related to the amount of streamflow caused by climate change. Therefore, it"s required to address potential influence from climate change for effective water resource management and prepare suitable measurement for water resource.

Projections of summertime ozone concentration over East Asia under multiple IPCC SRES emission scenarios

Lee, Jae-Bum,Cha, Jun-Seok,Hong, Sung-Chul,Choi, Jin-Young,Myoung, Ji-Su,Park, Rokjin J.,Woo, Jung-Hun,Ho, Changhoi,Han, Jin-Seok,Song, Chang-Keun Elsevier 2015 Atmospheric environment Vol.106 No.-

<P><B>Abstract</B></P> <P>We have developed the Integrated Climate and Air Quality Modeling System (ICAMS) through the one-way nesting of global–regional models to examine the changes in the surface ozone concentrations over East Asia under future climate scenarios. Model simulations have been conducted for the present period of 1996–2005 to evaluate the performance of ICAMS. The simulated surface ozone concentrations reproduced the observed monthly mean concentrations at sites in East Asia with high R<SUP>2</SUP> values (0.4–0.9), indicating a successful simulation to capture both spatial and temporal variability. We then performed several model simulations with the six IPCC SRES scenarios (A2, A1B, A1FI, A1T, B1, and B2) for the next three periods, 2016–2025 (the 2020s), 2046–2055 (the 2050s), and 2091–2100 (the 2090s). The model results show that the projected changes of the annual daily mean maximum eight-hour (DM8H) surface ozone concentrations in summertime for East Asia are in the range of 2–8 ppb, −3 to 8 ppb, and −7 to 9 ppb for the 2020s, the 2050s, and the 2090s, respectively, and are primarily determined based on the emission changes of NO<SUB>x</SUB> and NMVOC. The maximum increases in the annual DM8H surface ozone and high-ozone events occur in the 2020s for all scenarios except for A2, implying that the air quality over East Asia is likely to get worse in the near future period (the 2020s) than in the far future periods (the 2050s and the 2090s). The changes in the future environment based on IPCC SRES scenarios would also influence the change in the occurrences of high-concentrations events more greatly than that of the annual DM8H surface ozone concentrations. Sensitivity simulations show that the emissions increase is the key factor in determining future regional surface ozone concentrations in the case of a developing country, China, whereas a developed country, Japan would be influenced more greatly by effects of the regional climate change than the increase in emissions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Change in ozone level is determined by the combination of NO<SUB>x</SUB> and NMVOC emissions. </LI> <LI> Ozone level over East Asia would get worse in the near future (the 2020s) than far future. </LI> <LI> A high-concentration event generally increases and more frequently occurs in the future. </LI> <LI> Change in ozone air quality in a developing country depends more on emissions change. </LI> <LI> Change in ozone air quality in a developed country depends more on climate change. </LI> </UL> </P>

한ㆍ일 도시가스산업의 생산성 비교분석

최인수(In Su Choi),도범성(Bum Sung Do),박창수(Chang Soo Park),박중구(Jung Gu Park) 한국가스학회 2009 한국가스학회지 Vol.13 No.2

본고는 21세기 들어 고유가와 기후변화협약에 대응하여 중요성이 더해지고 있는 한국과 일본의 도시가스기업의 생산성을 분석하였다. 맘퀴스트 생산성 지수(Malmquist Productivity Index: MPI)를 통해 1997년부터 2005년까지 한국 30개, 일본 5개 기업들의 재무제표를 활용하여 기간 전체로, 그리고 수요의 구조변화를 나타내었던 2000년을 기준으로 이전과 이후의 생산성을 평가하였다. 분석의 결과, 첫째, 1996년~2005년 전체 기간의 MPI 누적지수에서 한국의 도시가스산업이 일본보다 상위에 있는 것으로 분석되었다. 그러나 기간별로 본 MPI 개선효과는 일본의 경우 1997~2000년 동안 -1.03%에서 2001~2005년 동안에는 -1.72%로 근소한 차이를 나타낸 반면, 한국의 경우에는 전반기 0.37%(금융외환위기를 경험한 98년 제외시 0.80%)이었지만 후반기에 -0.60%로 악화된 것으로 나타났다. 둘째, 후반기 한국의 MPI 악화는 기술적 효율성 지수보다는 기술변화 지수가 전반기 -0.88%(98년 제외시 0.29%)에서 후반기 -1.29%로 크게 악화된 것에 기인하는 것으로 분석되었다. 이에 따라 한국의 도시가스사업은 2001년 이후 악화되고 있는 생산성 증가율과 악화의 요인이 되고 있는 기술변화를 개선하는 정책적 노력이 필요하다. This article makes a comparative analysis on the productivity in gas distribution industry between Korea and Japan, using Malmquist productivity index(MPI). The estimated MPI during 1997~2005 shows that the productivity of Korean gas distribution industry has been generally higher than that of Japanese gas distribution industry. But Korean MPI made a drastic change from positive improvement (+ 0.37) during 1997~2000 to severe deterioration (-0.60) during 2001~2005, while Japan MPI has seldom changed. This change of Korean MPI is analyzed to result from the worsening of technical change rather than technical efficiency change. According to this result, Korean gas distribution industry needs to improve the technical change.

A two-photon ratiometric probe for hydrogen polysulfide (H₂S_n): Increase in mitochondrial H₂S_n production in a Parkinson’s disease model

Choi, Hyeon Jin,Lim, Chang Su,Cho, Myoung Ki,Kang, Ji Su,Park, Soo Jin,Park, Sang Myun,Kim, Hwan Myung Elsevier 2019 Sensors and actuators. B, Chemical Vol.283 No.-

<P><B>Abstract</B></P> <P>Hydrogen polysulfide (H<SUB>2</SUB>S<SUB>n</SUB>, n>1), which is primarily generated during the crosstalk between H<SUB>2</SUB>S and reactive species (ROS and RNS), is receiving increasing attention in biochemical research. H<SUB>2</SUB>S<SUB>n</SUB> is mostly generated in the mitochondria, and abnormal mitochondrial function and oxidative stress are directly related to many disorders including Parkinson's disease (PD). We now report a two-photon fluorescent probe (<B>SPS-M1</B>) for in situ detection of H<SUB>2</SUB>S<SUB>n</SUB> and its application to a PD model to account the H<SUB>2</SUB>S<SUB>n</SUB> levels. The probe exhibited selective and fast response to H<SUB>2</SUB>S<SUB>n</SUB> along with a marked blue-to-green color change. <B>SPS-M1</B> is sensitive enough to quantitative detection of endogenous H<SUB>2</SUB>S<SUB>n</SUB> content in mitochondria using two-photon microscopy (TPM). Ratiometric TPM imaging of live neurons and brain slices using <B>SPS-M1</B> revealed that H<SUB>2</SUB>S<SUB>n</SUB> production is increased to a greater extent in the A53 T α-synuclein (α-syn) overexpressing model than in the wild-type control. These findings suggest that the interactions of H<SUB>2</SUB>S and the increased ROS caused by α-syn overexpression may generate more H<SUB>2</SUB>S<SUB>n</SUB>. By employing our recently published TP probe for mitochondrial H<SUB>2</SUB>S, we also found the relationship between the H<SUB>2</SUB>S<SUB>n</SUB> and H<SUB>2</SUB>S; increased H<SUB>2</SUB>S<SUB>n</SUB> and decreased H<SUB>2</SUB>S levels, indicating that H<SUB>2</SUB>S and H<SUB>2</SUB>S<SUB>n</SUB> may play a significant role in the pathogenesis of PD. This result may be useful to biomedical studies, including PD.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A two-photon excitable and emission ratiometric probe for hydrogen polysulfide (H<SUB>2</SUB>S<SUB>n</SUB>) in mitochondria was developed. </LI> <LI> The probe is able to direct visualization of the endogenous H<SUB>2</SUB>S<SUB>n</SUB> level using two-photon microscopy (TPM). </LI> <LI> Ratiometric TPM imaging revealed that H<SUB>2</SUB>S<SUB>n</SUB> production is increased in a Parkinson’s Disease model. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Comparison of changes in retentive force of three stud attachments for implant overdentures

Su-Min Kim,Jae-Won Choi,Young-Chan Jeon,Chang-Mo Jeong,Mi-Jung Yun,So-Hyoun Lee,Jung-Bo Huh 대한치과보철학회 2015 The Journal of Advanced Prosthodontics Vol.7 No.4

PURPOSE The aim of this study was to compare the changes in retentive force of stud attachments for implant overdentures by in vitro 2-year-wear simulation. MATERIALS AND METHODS Three commercially available attachment systems were investigated: Kerator blue, O-ring red, and EZ lock. Two implant fixtures were embedded in parallel in each custom base mounting. Five pairs of each attachment system were tested. A universal testing machine was used to measure the retentive force during 2500 insertion and removal cycles. Surface changes on the components were evaluated by scanning electron microscopy (SEM). A Kruskal-Wallis test, followed by Pairwise comparison, was used to compare the retentive force between the groups, and to determine groups that were significantly different (α<.05). RESULTS A comparison of the initial retentive force revealed the highest value for Kerator, followed by the O-ring and EZ lock attachments. However, no significant difference was detected between Kerator and O-ring (P>.05). After 2500 insertion and removal cycles, the highest retention loss was recorded for O-ring, and no significant difference between Kerator and EZ lock (P>.05). Also, Kerator showed the highest retentive force, followed by EZ lock and O-ring, after 2500 cycles (P<.05). Based on SEM analysis, the polymeric components in O-ring and Kerator were observed to exhibit surface wear and deformation. CONCLUSION After 2500 insertion and removal cycles, all attachments exhibited significant loss in retention. Mechanism of retention loss can only be partially explained by surface changes.

자동차 칵핏 모듈용 플라스틱 소재의 열화 동특성 평가

우창수(Chang Su Woo),박현성(Hyun Sung Park),조진호(Jin Ho Jo),김지훈(Ji Hoon Kim),최주호(Ju Ho Choi),김영국(Yeoung Kuk Kim) 대한기계학회 2012 大韓機械學會論文集A Vol.36 No.12

플라스틱 소재는 온도, 습도 및 자외선 등 다양한 환경의 영향으로 인해 기계적 물성변화가 심하기 때문에 체결부의 견고함이 느슨해지고 형태의 변형에 의해 부품간의 마찰 등을 유발하여 잡음이 발생하게 된다. 따라서, 본 논문에서는 자동차 칵핏 모듈에 사용되는 다양한 플라스틱 소재에 대해 온도변화에 따른 동 특성시험을 통해 유리전이온도, 저장탄성계수, 손실계수 등을 측정하여 상온 및 열화조건에 따른 물성변화를 파악하였다. 시험결과, 온도가 높을수록 저장탄성계수는 감소하고 손실계수는 증가하는 경향을 나타내었다. Engineering plastics are used in instrument panels, interior trim, and other vehicle applications, and the thermomechanical behaviors of plastic materials are strongly influenced by many environmental factors such as temperature, sunlight, and rain. As the material properties change, the mechanical parts create unexpected noise. In this study, the dynamic mechanical property changes of plastics used in automobiles are measured to investigate the temperature effects. Viscoelastic properties such as the glass transition temperature and storage modulus and loss factor under temperature and frequency sweeps were measured. The data were compared with the original ones before aging to analyze the behavior changes. It was found that as the temperature increased, the storage modulus decreased and the loss factor increased slightly.

Comparison of changes in retentive force of three stud attachments for implant overdentures

Kim, Su-Min,Choi, Jae-Won,Jeon, Young-Chan,Jeong, Chang-Mo,Yun, Mi-Jung,Lee, So-Hyoun,Huh, Jung-Bo The Korean Academy of Prosthodonitics 2015 The Journal of Advanced Prosthodontics Vol.7 No.4

PURPOSE. The aim of this study was to compare the changes in retentive force of stud attachments for implant overdentures by in vitro 2-year-wear simulation. MATERIALS AND METHODS. Three commercially available attachment systems were investigated: Kerator blue, O-ring red, and EZ lock. Two implant fixtures were embedded in parallel in each custom base mounting. Five pairs of each attachment system were tested. A universal testing machine was used to measure the retentive force during 2500 insertion and removal cycles. Surface changes on the components were evaluated by scanning electron microscopy (SEM). A Kruskal-Wallis test, followed by Pairwise comparison, was used to compare the retentive force between the groups, and to determine groups that were significantly different (${\alpha}$<.05). RESULTS. A comparison of the initial retentive force revealed the highest value for Kerator, followed by the O-ring and EZ lock attachments. However, no significant difference was detected between Kerator and O-ring (P>.05). After 2500 insertion and removal cycles, the highest retention loss was recorded for O-ring, and no significant difference between Kerator and EZ lock (P>.05). Also, Kerator showed the highest retentive force, followed by EZ lock and O-ring, after 2500 cycles (P<.05). Based on SEM analysis, the polymeric components in O-ring and Kerator were observed to exhibit surface wear and deformation. CONCLUSION. After 2500 insertion and removal cycles, all attachments exhibited significant loss in retention. Mechanism of retention loss can only be partially explained by surface changes.

자동차 칵핏 모듈용 플라스틱 소재의 열화 동특성 평가

우창수(Chang Su Woo),박현성(Hyun Sung Park),조진호(Jin Ho Jo),김지훈(Ji Hoon Kim),최주호(Ju Ho Choi),김영국(Yeoung Kuk Kim) 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.5-2

플라스틱 소재는 온도, 습도 및 자외선 등 다양한 환경의 영향으로 인해 기계적 물성변화가 심하기 때문에 체결부의 견고함이 느슨해지고 형태의 변형에 의해 부품간의 마찰 등을 유발하여 잡음이 발생하게 된다. 따라서, 본 논문에서는 자동차 칵핏 모듈에 사용되는 다양한 플라스틱 소재에 대해 온도변화에 따른 동 특성시험을 통해 유리전이온도, 저장탄성계수, 손실계수 등을 측정하여 상온 및 열화조건에 따른 물성변화를 파악하였다. 시험결과, 온도가 높을수록 저장탄성계수는 감소하고 손실계수는 증가하는 경향을 나타내었다. Engineering plastics are used in instrument panels, interior trim, and other vehicle applications, and the thermo-mechanical behaviors of plastic materials are strongly influenced by many environmental factors such as temperature, sun light, and rain. As the properties change, the mechanical parts creating unexpected noise. In this paper, the dynamic mechanical property changes of plastics for automobiles are measured to investigate the temperature effects. Visco-elastic properties such as the glass transition temperature and storage modulus and loss factor under temperature and frequency sweeps were measured. The data were compared with the original ones before the aging to analyze the behavior changes. As results, the temperature was increased, the storage modulus was decreased on the other hand, loss factor is slightly increases.

Impact of urban warming on earlier spring flowering in Korea

Jeong, Jee‐,Hoon,Ho, Chang‐,Hoi,Linderholm, Hans W.,Jeong, Su‐,Jong,Chen, Deliang,Choi, Yong‐,Sang John Wiley Sons, Ltd. 2011 International journal of climatology Vol.31 No.10

<P><B>Abstract</B></P><P>Using long‐term (1954–2004) observations of four selected species in South Korea: goldenbell (<I>Forsythia koreana</I>), azalea (<I>Rhododendron mucronulatum</I>), cherry (<I>Prunus yedoensis</I>), and peach (<I>Prunus persica</I>), the impact of urban warming on spring flowering was investigated. Trends of early spring temperatures and first‐flowering dates (FFDs) of the four plants were cross‐compared among nine differently urbanized cities. It was clearly observed that urban warming has led to an advance in the timing of first‐flowering of several days to weeks during recent decades, while the intrinsic physiology of plants to sense thermal energy has not been changed. The degree of advancement of the FFD was observed to be roughly proportional to degree of urbanization. Moreover, the sensitivity of the FFD to urban warming was estimated to be higher for the shrub species (−9.07 and −6.64 days °C<SUP>−1</SUP> for goldenbell and azalea, respectively) than the tree species (−2.46 and −2.90 days °C<SUP>−1</SUP> for peach and cherry, respectively). Our results suggest that the impact of urban warming should be considered as an influential factor which drives changes in the regional natural environment, especially in regions of rapid urbanization. Copyright © 2010 Royal Meteorological Society</P>

알칼리 전해액의 상호작용에 의한 Stainless Steel 주성분의 변화 분석

변창섭,임수곤,김수곤,최호상,신훈규,Byun, Chang-Sub,Lim, Soo-Gon,Kim, Su-Kon,Choi, Ho-Sang,Shin, Hoon-Kyu 한국전기전자재료학회 2013 전기전자재료학회논문지 Vol.26 No.7

In this paper, We studied the change of surface and variation of elements on both electrodes of hydrogen generator of alkaline electrolysis in use of FE-SEM and SIMS. We used the stainless steel 316(600 ${\mu}m$) as electrode in condition of 25%KOH, $60^{\circ}C$ Temperature. The results show that the intensity of elements (C, Si, P, S, Ti, Cr, Mn, Fe, Ni, Mo) of Positive Electrode are decreased as much as about $10^1{\sim}10^3 $than the original electrode. Thickness of Positive Electrode is decreased about 40 ${\mu}m$ after chemical reaction. The negative electrode, however, shows a slight variation in the intensity of elements (C, Si, P, Fe, Ni, Mn, Mo) but Change of thickness and surface' shape of electrode show nothing after chemical reaction. The change in thickness and variation of Stainless Steel 316 cause the lifetime of electrode to be shorted. We also observed hydrogen, oxygen, potassium in both electrodes. Especially, The potassium is increased in proportional with depth of positive electrode. this means the concentration of alkali solutions is changed. and so we have to supply alkaline solution to generator in order to produce same quantity of hydrogen gas continuously. we hope that this study gives a foundation to develop the electrode for hydrogen generator of alkaline electrolysis.