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      • 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>

      • Allogenic succession of Korean fir (<i>Abies koreana Wils.</i>) forests in different climate condition

        Lim, Chi Hong,An, Ji Hong,Jung, Song Hie,Lee, Chang Seok Springer Japan 2018 Ecological research Vol.33 No.2

        <P><B>Abstract</B></P><P>This study was conducted to clarify the changes in vegetation that occurred due to changing environmental factors, especially climate, at Korean fir (<I>Abies koreana</I>) stands with different climatic conditions established on Mt. Halla, which is located on a southern island of South Korea. The difference of species composition between sites was large and depended on elevation and slope aspect at lower elevations, whereas not as much among stands or between sites at the highest elevations of each slope aspect. It was interpreted that differences and similarities among sites were dominated by the microclimate determined by the topographic conditions of each site. The result of vegetation dynamics analysis predicted that the Korean fir forests would be replaced by temperate forests such as Mongolian oak (<I>Quercus mongolica</I>) forests or shade intolerant forests composed of early successional species such as Korean cherry (<I>Prunus maximowiczii</I>) and Spreading yew (<I>Taxus cuspidata</I>) at lower elevations, while would continuously persist at the highest elevations. We interpreted the vegetation changes appeared at the lower elevations as an allogenic succession, as the recent rapid climate changes directly and indirectly dominated the change. The species distribution modeling predicted that the distributional range of Korean fir would decrease to 13.4 and 10.1% of the current distribution in 2050 and 2070, respectively. Further, the distribution modeling showed that the sites located at lower elevations would no longer be within the distributional range of Korean fir forest, and those at the highest elevations would be sparsely scattered in fragmented states.</P>

      • SCISCIESCOPUS

        Late Pleistocene-Holocene sedimentary facies and evolution of the Jeju Strait shelf, southwest Korea

        Hong, Seok-Hwi,Chang, Tae Soo,Lee, Gwang-Soo,Kim, Jin Cheul,Choi, Jooah,Yoo, Dong-Geun PERGAMON PRESS LTD 2019 QUATERNARY INTERNATIONAL Vol.519 No.-

        <P><B>Abstract</B></P> <P>The depositional environments of the Jeju Strait shelf since the last interglacial period are analyzed using sedimentary structures, grain size textures, sediment color, and optically-stimulated luminescence (OSL) and accelerator mass spectrometry (AMS) ages of vibro-cores. The shelf deposits can be divided into 12 sedimentary facies grouped into four depositional units: 1) shelf sand, 2) estuarine sand/mud, 3) fluvial sand/mud, and 4) shelf sand/mud. Each unit is separated by a sharp and unconformable erosion boundary. Unit 1 shows massive to slightly bedded sandy shells with oyster fragments, representing a shelf environment during sea-level highstand. The OSL date of the base of the unit is 124.4 ± 10.0 ka. Unit 2 is characterized by thin periodic parallel laminated mud, suggesting tidal signatures in tidal flats. Sediments are typically moderate brownish, suggesting extreme weathering after deposition. The OSL dates of this unit range from 81.1 ± 5.3 to 74.2 ± 4.7. Unit 3 consists of lower cross-bedded sand and laminated mud with fining-upward successions. It is interpreted as the product of channel deposits in a fluvial environment during a sea-level falling. The OSL ages of Unit 3 range from 50.6 ± 2.9 to 26.1 ± 1.6 ka, belonging to the Weichselian glacial period. The uppermost unit (Unit 4) is composed of homogeneous mud and massive sand with molluscan shell fragments in the modern shelf environment during sea-level highstand. OSL and <SUP>14</SUP>C-AMS ages range from 0.32 ± 0.02 to 11.2 ± 0.1 ka. Consequently, the late Pleistocene-Holocene sedimentary facies in this area consist of marine and non-marine environments, which mainly correspond to sea-level changes.</P>

      • KCI등재

        Study on Aging Effect of Adhesion Strength Between Polyimide Film and Copper Layer

        Seok‑Bon Koo,Chang‑Myeon Lee,Sang‑Jun Kwon,Jun‑Mi Jeon,Jin‑young Hur,Hong‑Kee Lee 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.1

        This paper experimentally confirmed that the adhesion strength of the copper layer formed on the surface of the polyimidefilm by wet plating greatly changes with the aging time. The adhesion strength of the copper layer showed a rapid increasefrom 4 to 10 h after aging had begun and then converged to a value without a significant change. The adhesion enhancementbetween polyimide film and copper layer by aging is due to the interlocking effect caused by the volume expansion of copperoxide (CuO) formed in the polyimide, the increased mobility of copper particles enlarged by the decrease of impuritiesin the copper layer grain boundaries, and the consequent change of the crystal structure of the copper layer leading to theinternal stress reduction. Such adhesion improvement can be confirmed by the progress of the cohesive failure indicatingthe breakdown of the polyimide film.

      • KCI등재

        혼입불순물이 구리 도금층의 미세조직변화에 미치는 영향

        구석본(Seok-Bon Koo),전준미(Jun-Mi Jeon),이창면(Chang-Myeon Lee),허진영(Jin-Young Hur),이홍기(Hong-Kee Lee) 한국표면공학회 2018 한국표면공학회지 Vol.51 No.4

        The self-annealing which leads evolution of microstructure in copper electroplating layers at room temperature occurs after forming deposition layer. During the process, crystal orientation, size and sheet resistance of plating layer change. Lastly, it causes the change of physical and mechanical characteristics such as a tensile strength of plating layer. In this study, the variation of incorporated impurities, microstructure and sheet resistance of copper plating layer formed by electroplating are measured with and without inorganic additives during the self-annealing. In case of absence of inorganic additives, the copper layer presents strong total intensity of incorporated impurities. During the self-annealing, such width of reduction was significant. Moreover, microstructure and crystal size are increased while the tensile strength is decreased noticeably. On the other hand, in the presence of inorganic additives, there is no observable distinction in the copper plating layer. According to the observation on movements of the incorporated impurities in electrodeposition copper layer, within 12 hours the impurities are continuously shifted from inside of the plating layer to its surface after as-deposited electroplating. Within 24 hours, except for the small portion of surface layer, it is considered that most of the microstructure is transformed.

      • 농촌용수의 효율적 이용 및 관리방안

        박석두(Seok-Doo Park),김홍상(Hong-Sang Kim),김창호(Chang-Ho Kim) 한국농촌경제연구원 2010 한국농촌경제연구원 기본연구보고서 Vol.- No.-

        Water use in South Korea has been continuously increasing capacity, as the current water supply is exceeding water demand. But it’s hard to build new water supply of facilities such as dams or reservoirs because of difficulty of the site selection, oppositions to environmental destruction and ecological damage, and climate change. A way to overcome water shortages is water saving or efficiency of water use but the most important method is the efficient use of agricultural water and water facilities. Therefore, the purpose of this study is to present efficient use and management of agricultural water. In chapter 2, Status of the total water resources, agricultural water supply, and water quality was investigated.. According to Waterplan 2006, the amount of water resources is expected to slightly increase but the amount of water use is to rapidly increase. Agricultural water demand is expected to continue to decline. Measures to supply water to the multi-purpose dam was built and five dams under construction. Agricultural water development projects are in progress but now more than expanding the water supply, water demand reductions should be carried out. And agricultural water quality improvement is needed. In chapter 3, agricultural water facilities and maintenance business were performed foe the present and future. Irrigated paddy field rates of frequency of drought possibility in 10 years are low, and agricultural water supply facility for elderly rates are high. There are too many small facilities and earthwork waterways. Water supply facility maintenance expenses for agriculture are increasing each year and state benefits and Korea Rural community Corporation’s own financing have been increasing recently. In chapter 4, Use and management systems of agricultural water and water facilities were studied. There are several of the water resources ministry that are managing such as ministry of land, transport and maritime affairs, ministry of environment, Ministry of food, agriculture, forestry and fisheries etc, and there are a lot of laws. Therefore, there are so many ministries and laws that it causes problems such as adjustment and management of water, focusing on development only, absence of standard for own agricultural water quality etc. In chapter 5, as the result of this study, rather than building new facilities to using and managing efficiently are set to the basic policy direction and we suggested some policy strategies to reformation of irrigation facilities for agriculture. Change irrigation and drainage canal to pipe-lined water-way, addition and improvement or reuse the existing irrigation facilities, multi-purpose use of agricultural water. Also we suggested the reorganization plan of management system for the irrigation facilities that systematic development and use plan for agricultural water, change the state benefits for the management of irrigation facilities to Korea Rural community Corporation’s own business work, integrated management organization system.

      • 묵논의 식생천이에 관한 연구

        이창석,박현숙,유영한,홍선기 서울여자대학교 자연과학연구소 1998 자연과학연구논문집 Vol.10 No.-

        폐경년도가 다른 묵논에서 식생요인과 환경요인의 변화를 분석하여 천이계열 및 천이의 추진 기작을 밝혔다. 조사지소는 경작 중인 논, 폐경 후 3년(초기 묵논), 7년(중기 묵논) 및 10년째의 묵논(후기 묵논) 및 묵논에 인접한 계곡림(극상림)의 5단계로 구분하였다. 경작 중인 논, 초기 묵논, 중기 묵논, 후기 묵논 및 계곡림에서 각 조사지소의 우점종으로 판단한 천이계열은 뚝새풀군락→사마귀풀군락→갯버들군락→오리나무군락의 순서로 나타났다. 천이단계별 우점종의 분포와 그것의 생활령을 분석하여 파악된 천이의 추진기작은 내성모델을 따르는 것으로 밝혀졌다. 천이단계에 따른 다양성지수의 변화에서 종품부도와 종다양성지수는 초기에 증가하고 중기에 감소하였다가 그 이후 다시 증가하는 경향을 보였으나 균등성지수는 큰 변화가 없었다. 직경급분포도에서 중기 묵논의 갯버들개체군은 정규분포형을, 후기 묵논의 것은 역 J자형을 보여 전자는 그들이 과거적 어느 한 시기에 동시적으로 출현하였음을 반영하고, 후자의 것은 그들이 현재 경쟁상태에 있음을 반영하였다. 후기 묵논에 성립된 오리나 무개체군의 직경급분포도는 역 J자형을 보여 그들이 침입단계에 있음을 반영하였고, 계곡립의 것은 정규분포형을 보여 그들이 안정상태에 있음을 반영하였다. 이러한 식생요인에 대한 분석 결과, 현재 논으로 이용되고 있는 지역의 잠재자연식생은 오리나무군락이 될 것으로 판단되었다. 천이의 진행에 따른 토양환경요인의 변화에서 수분한량은 초기 묵논에서 현저히 증가되었고, 중기 이후의 묵논에서 감소하였다. pH는 큰 변화를 나타때지 않았고, 유기물, N, P, K, Ca 및 Mg함량은 천이의 진행에 따라 증가하는 경향을 보였다. To clarify the vegetational sere and driving mechanism of succession, vegetation and soil environmental factors were investigated in the old paddy field with different in the lapsed years after abandonment, Study sites were divided into 5 stages of the paddy field under cultivation, the old paddy fields of the initial, middle and late stages, and the climax forest of the mountainous valley near to the abandoned paddy fields. Sere estimated from dominant species of above mentioned study sites was shown in the order of Alpecurus aequalis var. amurensis community, Aneilema keisak community, Juncus effusus var. decipiens community, Salix gracilityla community, and Alnus japonica communt. y. Driving mechanism of succession inferred from the distribution of dominant species in each successional stage and their life form was based on the tolerance model. Species richness and diversity indices steadily increased since the middle stage but evenness index did not show any distinct change. In frequency distribution diagrams of diameter classes, Salix gracilistyla population of the middle and the late stages showed normal and reverse J-shaped distribution patterns, respectively. Result of the former reflects that individuals composing of that poulation were invaded simultaneously in a given time of the past and that the latter suggests that they are in state of intraspecific competition. Distribution diagram of Alnus japonica population in the late stage showed reverse J-shaped distribution pattern reflects that those individulas are in the stages of invasion and that of the valley forest showed normal distribution pattern suggests that they are in stable stage. From the results of analyses on those vegetation data, it was interpreted that potential natural vegetation of the present paddy field might be Alnus japonica community. In changes of soil environmental factors with the progression of succession, soil moisture content rapidly increased in the initial stage and then decreased since the middle stage. Organic matter, N. P. K, Ca and Mg contents tended to increase with the succession stage but pH did not show any distinct change.

      • 서울의 Penicillinase Producing Neisseria Gonorrhoeae 발생빈도(1996)

        김재홍,황동규,전재홍,김윤석,김중환,김용준,이창균,임동진,김현수,조창근,김경문,박상훈,전우형,김희성,이호정,차명수,김갑형,김형석,김석우,황지환,박병순,권오상,이민수,송기훈,성소영,이인섭,부태성 대한화학요법학회 1999 대한화학요법학회지 Vol.17 No.2

        Background : In recent years, gonorrhea has been panedemic and remains one of the most commom STDs in the world, especially in developing countries. Objective & Methods: For the detection of a more effective therapeutic regimen and assessing the prevalence of PPNG, we have been trying to study the patients who have visited the VD Clinic of Choong-Ku Public Health Center in Seoul since 1980 by means of the chromogenic cephalosporin method. Results: In 1996, 139 strains of N. gonorrhoeae were isolated, among which 53(39.0%) were PPNG. Conclusion: Our results suggests that after a peak of 74.3% in 1993, the prevalence of PPNG in Seoul is gradually declining.

      • KCI등재

        2 ㎓ 선형 위상 천이 특성을 갖는 소형 아날로그 위상천이기

        오현석(Hyun-Seok Oh),최재홍(Jae-Hong Choi),정해창(Hae-Chang Jeong),허윤성(Yun-Seong Heo),염경환(Kyung-Whan Yeom) 한국전자파학회 2011 한국전자파학회논문지 Vol.22 No.1

        본 논문에서는 2 ㎓ 선형 위상 천이 특성을 갖는 위상천이기를 설계 및 제작하여 보였다. 소형의 위상 천이기 구현을 위해 집중소자로 구성된 전통과 회로망(all pass network)을 기반으로 위상천이기를 구성하고, 박막 세라믹 공정을 이용하여 제작하였다. 또한, 선형의 위상 천이 특성을 얻기 위해 버랙터(varactor) 다이오드에 직렬 커패시터를 연결하여, 전압에 대한 커패시턴스를 선형화함으로써 비선형성을 개선하였다. 전통과 회로망에 나타나는 인덕터는 스파이럴 인덕터로 구현하고, 이를 다이오드 바이어스 회로에 활용하여 4 ㎜×4 ㎜ 면적을 가지는 소형 위상천이기를 구성할 수 있었다. 또한, 온-웨이퍼(on wafer)로 측정을 위해 입출력은 CPW(Coplanar Waveguide) 형상으로 구현하였으며, 제작된 위상천이기는 버랙터 조정 전압 0~5 V에 대하여, 2 ㎓에서 삽입 손실은 약 4.2~4.7 ㏈, 위상 변화량은 약 79°였으며, 예상한대로 선형 위상 천이 특성을 보였다. In this paper, we present a 2 ㎓ compact analog phase shifter with linear phase-tune characteristic. The compact phase shifter was designed base on a lumped all pass network and implemented using a ceramic substrate fabricated with thin-film technique. For a linear phase-tune characteristic, a capacitance of the varactor diode for a tuning voltage was linearized by connecting series capacitor and subsequently produced an almost linear capacitance change. The inductor and bias circuit in the all pass network was implemented using a spiral inductors for small size, which results in the size reduction to 4 ㎜×4 ㎜. In order to measure the phase shifter using the probe station, two CPW pads are included at the input and output. The fabricated phase shifter showed an insertion loss of about 4.2~4.7 ㏈ at 2 ㎓ band and a total 79° phase change for DC control voltage from 0 to 5 V, and showed linear phase-tune characteristic as expected in the design.

      • KCI등재

        Genome-Wide Analysis of DNA Methylation before- and after Exercise in the Thoroughbred Horse with MeDIP-Seq

        Gim, Jeong-An,Hong, Chang Pyo,Kim, Dae-Soo,Moon, Jae-Woo,Choi, Yuri,Eo, Jungwoo,Kwon, Yun-Jeong,Lee, Ja-Rang,Jung, Yi-Deun,Bae, Jin-Han,Choi, Bong-Hwan,Ko, Junsu,Song, Sanghoon,Ahn, Kung,Ha, Hong-Seok Korean Society for Molecular and Cellular Biology 2015 Molecules and cells Vol.38 No.3

        Athletic performance is an important criteria used for the selection of superior horses. However, little is known about exercise-related epigenetic processes in the horse. DNA methylation is a key mechanism for regulating gene expression in response to environmental changes. We carried out comparative genomic analysis of genome-wide DNA methylation profiles in the blood samples of two different thoroughbred horses before and after exercise by methylated-DNA immunoprecipitation sequencing (MeDIP-Seq). Differentially methylated regions (DMRs) in the pre-and post-exercise blood samples of superior and inferior horses were identified. Exercise altered the methylation patterns. After 30 min of exercise, 596 genes were hypomethy-lated and 715 genes were hypermethylated in the superior horse, whereas in the inferior horse, 868 genes were hypomethylated and 794 genes were hypermethylated. These genes were analyzed based on gene ontology (GO) annotations and the exercise-related pathway patterns in the two horses were compared. After exercise, gene regions related to cell division and adhesion were hypermethylated in the superior horse, whereas regions related to cell signaling and transport were hypermethylated in the inferior horse. Analysis of the distribution of methylated CpG islands confirmed the hypomethylation in the gene-body methylation regions after exercise. The methylation patterns of transposable elements also changed after exercise. Long interspersed nuclear elements (LINEs) showed abundance of DMRs. Collectively, our results serve as a basis to study exercise-based reprogramming of epigenetic traits.

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