http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
플라즈마 표면처리를 이용한 YBCO Coated Conductor의 Ag 박막층 증착에 관한 연구
정현기,양성채,최병정,두호익,Jeong, Hyun-Gi,Yang, Sung-Chae,Choi, Byoung-Jung,Du, Ho-Ik 한국전기전자재료학회 2017 전기전자재료학회논문지 Vol.30 No.1
The Ag thin film of YBCO (yttrium barium copper oxide) CC (coated conductor) protect the YBCO layer and, at the same time, affects the electrical characteristics of the YBCO CC. Therefore, YBCO CC with the commercialization of the Ag thin film layers makes it easy to establish a process, it can lead to a variety of characteristic changes in YBCO CC. In this paper, plasma surface treatment was carried out to facilitate the deposition of the Ag thin film and the deposition process of YBCO CC. Surface roughness from the test results was increased as the time of the plasma surface treatment increased from 5 to 20 minutes. On the other hand, the surface roughness was decreased for the time of the plasma surface treatment over 20 minutes. Furthermore, after depositing, the increasing of deposit amount and reduced lifting phenomenon showed a similar tendency with the rise time of surface roughness.
여름철 얕은 저수지의 중앙과 연안에서 동물플랑크톤 군집의 서식지 선택
정현기 ( Hyun Gi Jeong ),서정관 ( Jung Kwan Seo ),이혜진 ( Hae Jin Lee ),이원철 ( Won Choel Lee ),이재관 ( Jaek Wan Lee ) 한국환경생물학회 2010 환경생물 : 환경생물학회지 Vol.28 No.4
The Abundance of zooplankton was studied in the pelagic and the littoral zone in four shallow reservoirs along with the Nakdong river basin of S. Korea. In the pelagic zone, there was a higher zooplankton density (477.5±312.4 ind. L-1) than in the littoral zone during our study period (t=2.337, p?0.05). Overall, Rotifers were the most abundant group in the studied reservoirs. However, there are no significant correlations between the pelagic and the littoral zone in physical and chemical parameters. In the pelagic and the littoral zone, zooplankton density usually increased with increasing density of aquatic plants in the littoral zone. However, this study showed different trends. Although macrophyte abundance was higher in the littoral zone than in the pelagic zone, zooplankton abundance was higher in pelagic zone. Moreover, when macrophytes (Trapa japonica and Spirodela plyrhiza) covered the complete water surface of the reservoir, zooplankton abundance was higher. It appears that comparisons between the pelagic and the littoral zone give important cues on the selection of habitats by zooplankton. It is assumed that a higher density of aquatic plants does not always imply a higher density of zooplankton in the littoral zone. Furthermore, when the water surface was covered with aquatic plants, the zooplankton communities showed the highest density in the pelagic zone. These results imply that habitat selection of the zooplankton community (Rotifers) is influenced by aquatic plant density with an associated decrease in predation pressure during summer.
안동댐과 임하댐 유역에서 퇴적물 특성 및 오염도의 시·공간적 변화
김신,정현기,김형근,김주언,박수정,김용석,양득석,Kim, Shin,Jeong, Hyun-Gi,Kim, Hyoung-Geun,Kim, Ju-Eon,Park, Su-Jeong,Kim, Yong-Seok,Yang, Deuk-Seok 한국환경과학회 2019 한국환경과학회지 Vol.28 No.12
We investigated the spatial and temporal variation in characteristics and pollution assessment of sediments in the watersheds of Andong-Dam and Imha-Dam, in Korea. Surface sediments were collected from six sites once a year for three years (2015-2017), and analyzed for organic matter (water content, IL, COD, TOC, TN, and TP), grain size, and concentration of trace metals (Al, Li, Zn, Cr, Pb, Cu, Ni, and As). Organic matter generally tended to increase, and was higher in the Andong watershed compare to Imha watershed. Surface sediments were mainly composed of silt. Coarse sediments were mainly distributed at the site adjacent to Andong-Dam, and showed fining after coarsening. Fine sediment were mainly distributed at the site adjacent to Imha-Dam, and were gradually coarsening. Concentration of trace metals generally tended to increase, and was higher for sites in watershed of Andong watershed (PLI > 1) than for sites in Imha watershed (PLI < 1). Trace metals in the study area were considered to be affected by fine sediment (silt), and contamination of trace metals was somewhat affected by Pb, and greatly affected by Zn and As.
박연정 ( Yeon Jeong Park ),이혜진 ( Hae Jin Lee ),서정관 ( Jung Kwan Seo ),탁보미 ( Bo Mi Tak ),정현기 ( Hyun Gi Jeong ),이재관 ( Jae Kwan Lee ) 한국환경생물학회 2011 환경생물 : 환경생물학회지 Vol.29 No.4
This study was carried out to investigate the relation between water quality and structure of the aquatic ecosystem in the Lake Gachang from February to December in 2010. The annual mean COD (Chemical Oxygen Demand) in Lake Gachang was 3.5 mg L 1, indicating, level II of environmental standards and the trophic state was mesotrophic. The seasonal succession of phytoplankton showed that Bacillariophyceae was mostly dominant species throughout the year except August. In case of zooplankton, rotifers dominate in the most seasons, but copepod (Nauplii) in August. The macrophyte plants showed diverse species composition consisted of 9 varieties, 77 species, 64 genera, 34 families and 24 orders. Surveyed species of macroinvertebrates were classified into 1 phyla, 2 classes, 4 orders, 7 families, 9 species. The macroinvertebrates showed FFG (Functional Feeding Groups) such as GC (Gathering Collector) and SH (Shedder). A total of 42 species of fish was collected including Zacco koreanus and Coreoperca herzi. In this study, we investigated environmental factors including pollutant source, load, water quality and distribution characteristics of biota such as phytoplankton, zooplankton, macrophyte plants, macroinvertebrates, fish.
윤종수(Jong-su Yoon),정현기(Hyun-Gi Jeong),권영호(Young-Ho Kwon),신찬기(Chan-ki Shin),황동진(Dong-jin Hwang) 대한환경위생공학회 2008 대한환경위생공학회지 Vol.23 No.4
Our study indicates the zooplankton abundance with characteristics of water column and the vertical distribution in Lake Jinyang, South Korea. Seasonal changes of zooplankton community are determined by environmental parameters like water temperature, pH, dissolved oxygen, suspended solids and chlorophyll a. In lake Jinyang, this study showed that the zooplankton abundance in transition zone(St.1, St.2) was higher density than in lacustrine zone(St.3). Rotifers were dominant zooplankton and among them, Polyarthra spp., Keratella spp, and Nauplli(Copepoda) were common. But Cladoceran showed the low density. During survey period, zooplankton abundance with vertical distribution in surface layer(epilimnion) was higher than in bottom layer(hypolimninon). Zooplankton densities in Surface and middle layer showed positive relationship with water temperature and the densities in bottom layer(hypolimnion) showed positive relationship with chlorophyll a. Our assumption in spite of the short term study are supported by the facts that increase of temperature driven by climate change more maintains the thermocline duration by the summer temperature stratification. Thus the results suggest that the climate changes are an important source of changing zooplankton community feeding phytoplankton. So the zooplankton should be monitoring by the ecological management of Lake Jinyang to cope with climate changes like flood plain or drought.