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        검색결과 136

        81.
        1997.07 KCI 등재 구독 인증기관 무료, 개인회원 유료
        자동차 배출가스로 인한 대기 오염을 줄일 수 있는 자동차 연료용 고순도 에탄올 농축을 의한 투과증발 pilot test가 발효에탄올 시작 공장에서 PVA 복합막을 이용하여 수행되었다. 약 95% 에탄올 농도를 갖는 에탄올/물 공비혼합물을 탈수, 농축하여 99% 이상의 연료용 고순도 에탄올을 얻는 투과증발 공정에서는 막의 내열 온도 범위 내에서 공급액의 가열 온도를 높일수록 농축 성능이 우수하였으며 투과액의 응축 온도는 경제성을 고려하여 결정해야 하며 0℃가 최적임을 알 수 있었다. 발효에탄올 농축을 위한 투과증발 성능은 합성에탄올 농축과 같은 결과를 보임으로써 투과증발 시스템 성능은 에탄올에 포함된 미량의 성분과는 무관한 결과를 보였으며, 투과증발 pilot test 결과 및 에너지 수지 관계를 이용하여 시스템에 소비되는 에너지의 대부분을 차지하는 투과액의 기화에 필요한 에너지는 공급액의 현열에 의해 공급됨을 확인하였다.
        4,000원
        82.
        1996.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        ICB 공정으로 선행 증착한 Cu Seeding 층이 이후의 CVD 공정으로 증착하는 최종의 Cu 박막의 기계적 전기적 특성에 미치는 영향을 고찰하였고, seening을 하지 않은 CVD-Cu 박막과의 특성을 비교하였다. seeding 층을 형성한 경우의 CVD-Cu 박막에 있어서 증착 속도가 증가하였으며, grain 크기의 균일성도 향상되는 경향을 보였다. 증착된 Cu 박막은 seening에 무관하게 모두 FCC 우선배향인 (111)의 결정배향을 나타냈으며, seeding 우에 성정된 박막의 경우 I111/I200비가 향상되었다. 180˚C의 동일 조건하에서 증착하는 경우 40Å seeding층 위에 성장한 박막의 전기비저항이 2.42μΩ.cm로 낮은 값을 나타내었으며, 130Å seeding 경우는 오히려 전기비저항이 증가하는 경향을 나타내었다. Cu 박막의 접착력은 seeding층의 두께가 0Å에서 130Å으 증가함에 따라 21N에서 27N 으로 향상되었다.
        4,000원
        85.
        1977.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        4,500원
        86.
        2022.04 KCI 등재 서비스 종료(열람 제한)
        In this study, we analyzed the relationships between weather factors and photosystem II activity (Fv/Fm), as a measure of photochemical efficiency, in three cool-season turfgrasses commonly planted on golf courses in Jeju, South Korea: perennial ryegrass (Lolium perenne L.), Kentucky bluegrass (Poa pratensis L.), and creeping bentgrass (Agrostis palustris Huds.). In all three turfgrasses, Fv/Fm was higher during late summer than during early summer. However, in late summer, Fv/Fm was significantly lower in perennial ryegrass than in the other two species. In early summer, Fv/Fm in perennial ryegrass and Kentucky bluegrass was positively correlated with mean low temperature and extreme minimum temperature, whereas, in late summer, this parameter in Kentucky bluegrass and creeping bentgrass was positively correlated with relative humidity, and in creeping bentgrass was negatively correlated with mean high temperature, mean low temperature, and extreme maximum temperature. These results indicate that raising low temperatures is favorable for perennial ryegrass and Kentucky bluegrass in early summer, whereas, in late summer, the lowering of high temperatures proves to be beneficial for creeping bentgrass, and raising relative humidity is conducive to the growth of Kentucky bluegrass and creeping bentgrass. These findings will contribute to improving the selection and management of turfgrasses on golf courses and sports fields.
        87.
        2021.07 KCI 등재 서비스 종료(열람 제한)
        To compare the vitality among cool-season turfgrasses under summer weather conditions and to obtain information to improve the management of turfgrasses in golf courses and sports fields., the chlorophyll fluorescence of three cool-season turfgrasses commonly planted on golf courses in the Jeju area was measured. The turfgrasses were perennial ryegrass (Lolium perenne L.), Kentucky bluegrass (Poa pratensis L.), and creeping bentgrass (Agrostis palustris Huds.). In perennial ryegrass and Kentucky bluegrass, the chlorophyll index was low in early summer and high in late summer. In creeping bentgrass, it remained low throughout the study. Fo tended to be low in the early summer and high in late summer in the three turfgrasses. However, the difference in Fo between late summer and early summer was markedly higher in perennial ryegrass than in Kentucky bluegrass or creeping bentgrass. Fm tended to be low in early summer and high in late summer, without obvious differences among the three turfgrasses. Fv/Fm, a measure of photochemical efficiency, was also low in early summer and high in late summer in the three turfgrasses. However, Fv/Fm in late summer was mostly higher in Kentucky bluegrass and creeping bentgrass than in perennial ryegrass, indicating that the former are more resistant to the high temperature and humidity of late summer. Furthermore, Kentucky bluegrass had a high chlorophyll index in late summer and would be most resistant to the harsh conditions of late summer.
        88.
        2020.02 KCI 등재 서비스 종료(열람 제한)
        Seasonal changes in the CO2 fixation rate and water-use efficiency in the leaves of six evergreen and two deciduous broad-leaved tree species on Jeju Island, Korea, were measured using a portable photosynthesis analyzer, to identify which species are most efficient in taking up CO2 from the air. The CO2 fixation rate was high in the deciduous species in spring and summer and decreased in fall, whereas it was high in the evergreen species in summer and fall and decreased in winter. The rate remained high in the deciduous tree Prunus yedoensis from spring to fall (> 7.1 μmol CO2/m2/s) and in two evergreen trees, Castanopsis cuspidata var. sieboldii and Cinnamomum camphora, in summer and fall (7.0 9.9 μmol CO2/m2/s). Therefore, these tree species fix atmospheric CO2 effectively. The water-use efficiency was higher in evergreen species than in deciduous species regardless of the season. Exceptionally, it was high in the deciduous species Zelkova serrata in spring and summer (> 100 μmol CO2/mol H2O), suggesting that Z. serrata is a useful tree for dry conditions due to its tolerance of water stress. The regressions of the CO2 fixation rate versus the evaporation rate and stomatal conductance were linear and non-linear, respectively. This suggests that the stomatal activity of leaves plays an important part in CO2 fixation of plants. In conclusion, C. cuspidata var. sieboldii, C. camphora, and P. yedoensis should be planted along roads or in urban spaces for the greening of cities and mitigation of CO2 concentrations in the air.
        89.
        2018.04 서비스 종료(열람 제한)
        Crohn’s disease is a chronic inflammatory bowel disease, involving gastrointestinal tract and extra-intestinal organs. IgA nephropathy is a rare extra-intestinal manifestation of Crohn’s disease. We describe a case of 21-year old Korean man who was diagnosed with Crohn’s disease 5 years after IgA nephropathy was suspected. At the age of 16, he had gross hematuria and 2 years after he was diagnosed with IgA nephropathy. Three years later, he complained of abdominal pain and diarrhea. He was diagnosed with Crohn’s disease by colonoscopy and histologic exams. There has been increasing evidences of common pathophysiology between the two diseases.
        90.
        2018.04 서비스 종료(열람 제한)
        Recently, many concrete slab tracks have been adopted in high-speed railway. However, it is vulnerable to roadbed settlement compared to gravel tracks. Therefore, it was necessary to evaluate the long-term performance about roadbed and track of the concrete slab track. In this paper, the performance of track and roadbed is evaluated using long-term high-speed rail data. The measurement items are the Wheel load, Lateral load, Acceleration, Road pressure. The measurement period is from the beginning of construction to three years after opening. For the measurement method, a representative value of the measurement data was selected and compared with the reference value.
        91.
        2018.02 KCI 등재 서비스 종료(열람 제한)
        An unrecorded cactus species, Opuntia monacantha Haw. (Cactaceae), is newly reported in Korea. It was found growing on the coast of Jeju Island. It is distinguished from other Opuntia species by the following morphological characteristics. It is an erect succulent tree, commonly 2~3 m, but can reach 4 m. It is highly branched at the top and has drooping upper branches. The cladodes are oval to obovate, narrowing basally, and glossy green. It has yellow outer tepals with a reddish median stripe on the back. It produces purple fruit with yellowish green juicy pulp, which contains several rudimentary seeds and very few mature seeds (<2). The Korean name “Wang-seon-in-jang” is given to the species, based on the height of the plants and the large cladodes.
        92.
        2017.05 KCI 등재 서비스 종료(열람 제한)
        The effects of elevated atmospheric CO2 on growth and photosynthesis of soybean (Glycine max Merr.) were investigated to predict its productivity under elevated CO2 levels in the future. Soybean grown for 6 weeks showed significant increase in vegetative growth, based on plant height, leaf characteristics (area, length, and width), and the SPAD-502 chlorophyll meter value (SPAD value) under elevated CO2 conditions (800 μmol/mol) compared to ambient CO2 conditions (400 μmol/mol). Under elevated CO2 conditions, the photosynthetic rate (A) increased although photosystem II (PS II) photochemical activity (Fv/Fm) decreased. The maximum photosynthetic rate (Amax) was higher under elevated CO2 conditions than under ambient CO2 conditions, whereas the maximum electron transport rate (Jmax) was lower under elevated CO2 conditions compared to ambient CO2 conditions. The optimal temperature for photosynthesis shifted significantly by approximately 3°C under the elevated CO2 conditions. With the increase in temperature, the photosynthetic rate increased below the optimal temperature (approximately 30°C) and decreased above the optimal temperature, whereas the dark respiration rate (Rd) increased continuously regardless of the optimal temperature. The difference in photosynthetic rate between ambient and elevated CO2 conditions was greatest near the optimal temperature. These results indicate that future increases in CO2 will increase productivity by increasing the photosynthetic rate, although it may cause damage to the PS II reaction center as suggested by decreases in Fv/Fm, in soybean.
        93.
        2017.03 KCI 등재 서비스 종료(열람 제한)
        This study was carried out to develop new zoysiagrass (Zoysia japonica Steud.) cultivar ‘Halla Green 2’ (Grant number: No. 118). To develop a zoysiagrass cultivar with dwarfism by using the mutation breeding method, the wild type control "Gosan" plants were irradiated using a 30 Gy gamma ray source in 2010. Dwarf mutants were selected from the mutated grasses in successive generations. Dwarf mutant lines were identified and a new zoysiagrass variety Halla Green 2 was developed. The plant height of Halla Green 2 was 3.4 and 1.8 times lower than that of Gosan and Zenith, respectively. This cultivar has dwarf characteristics such as shorter sheath, shorter leaf blade, shorter flag leaf, and shorter third internode of stolon compared to those of Gosan and Zenith. Additionally, the sheaths and leaf blades color of Gosan, Zenith and Halla Green 2 were all light green, whereas their stolons were purple, yellow-green and yellow green, respectively. Trichomes(hairs) were visible on both adaxial and abaxial surfaces of the Gosan leaves, whereas only on the adaxial side of the Zenith and Halla Green 2 leaves. The Halla Green 2 grass showed distinguishable morphological traits compared to those of wild type Gosan and Zenith.
        94.
        2016.12 KCI 등재 서비스 종료(열람 제한)
        To develop a dwarf turfgrass (Zoysia japonica) cultivar with artificial mutation-induced breeding method, the wild type control "Gosan" plants were exposed to a 30 Gy gamma ray source in 2010. The mutant lines showing short height were selected from successive generations. One of the resulting dwarf lines obtained was registered under the cultivar name of “Halla Green 1” (2016). The dwarf phenotype of the Halla Green 1 includes a reduction of the height by 4.5-fold, an increase in leaf and third internode lengths by about 6- and 2.3-fold, respectively, compared to the Gosan, and approximately 2.4-, 3.8-, and 1.5-fold relative to the Zenith, respectively. In addition, the Halla Green 1 had a sheath of darker green coloring compared to the light green Gosan and Zenith. The leaf blades of Gosan, Zenith and Halla Green 1 were all light green, whereas their stolons were purple, yellow-green and light purple, respectively. Trichomes presented on both adaxial and abaxial surfaces of the Gosan’s leaves, and only on the adaxial side of the Zenith’s leaves, but none on the Halla Green 1 leaves. The Halla Green 1 exhibited sufficiently distinct morphological traits when compared with the wild type Gosan and Zenith that the dwarf phenotype enhances its commercial viability.
        95.
        2016.12 서비스 종료(열람 제한)
        Acinetobacter baumannii is one of the most problematic causative agents of nosocomial infections, especially in the immune compromised or patients in intensive care units. In recent years, as multiple antibiotic resistant A. baumannii has increasingly emerged, it has become difficult to treat infections effectively. The authors report a case of extreme drug resistant A. baumannii bacteremia caused by catheter-related infection, as confirmed by blood and catheter tip culture, in a 63-year-old man. The patient responded well to 24 days of doripenem and colistin treatment.
        96.
        2016.08 KCI 등재 서비스 종료(열람 제한)
        Plant biomass, photosystem II (PSII) photochemical activity, photosynthetic function, and zinc (Zn) accumulation were investigated in a sorghum-sudangrass hybrid (Sorghum bicolor × S. sudanense) exposed to various Zn concentrations to determine the elimination capacity of Zn from soils. Plant growth and biomass of the sorghum-sudangrass hybrid decreased with increasing Zn concentration. Symptoms of Zn toxicity, i.e., withering and discoloration of old leaves, were found at Zn concentrations over 800 ppm. PSII photochemical activity, as indicated by the values of Fv/Fm and Fv/Fo, decreased significantly three days after exposure to Zn concentrations of 800 ppm or more. Photosynthetic CO2 fixation rate (A) was high between Zn concentrations of 100-200 ppm (22.5 μmol CO2・m –2・s –1), but it declined as Zn concentration increased. At Zn concentrations of 800 and 1600 ppm, A was 14.1 and 1.8 μmol CO2・m –2・s –1, respectively. The patterns of stomatal conductance (gs), transpiration rate (E), and water use efficiency (WUE) were all similar to that of photosynthetic CO2 fixation rate, except for dark respiration (Rd), which showed an opposite pattern. Zn was accumulated in both above- and below-ground parts of plants, but was more in the below-ground parts. Magnesium (Mg) and iron (Fe) concentrations were significantly low in the leaves of plants, and symptoms of Mg or Fe deficiency, such as a decrease in the SPAD value, were found when plants were treated with Zn concentrations above 800 ppm. These results suggest that the sorghum-sudangrass hybrid is able to accumulate Zn to high level in plant body and eliminate it with its rapid growth and high biomass yield.
        97.
        2016.04 서비스 종료(열람 제한)
        Civil engineering structures are damaged due to secondary damages from floods. The purpose of this study is a comparative study of past recovery cases and disaster recovery scenarios developed. Disaster recovery scenarios developed with respect to the 6 structures for rapid recovery. The development scenarios were compared with past recovery cases. The results were consistent 70%.
        98.
        2015.12 KCI 등재 서비스 종료(열람 제한)
        The response of the freshwater microalga, Chlorella vulgaris, to heavy metal stress was examined based on chlorophyll fluorescence analysis to assess the toxic effects of heavy metals in freshwater ecosystems. When toxic effects were analyzed using regular chlorophyll fluorescence analysis, photosystem II activity(Fv/Fm) decreased significantly when exposed to Cu2+ and Hg2+ for 12 h, and decreased in the order of Hg2+ > Cu2+ > Cd2+ > Ni2+ when exposed for 24h. The effective photochemical quantum yield(Φ′PSII), chlorophyll fluorescence decrease ratio(RFd), minimal fluorescence yield(Fo), and non-photochemical quenching(NPQ), but not photochemical quenching(qP), responded sensitively to Hg2+, Cu2+, and Cd2+. These results suggest that Fv/Fm, as well as Φ′PSII, RFd, Fo, and NPQ could be used to assess the effects of heavy metal ions in freshwater ecosystems. However, because many types of heavy metal ions and toxic compounds co-occur under natural conditions, it is difficult to assess heavy metal toxicity in freshwater ecosystems. When Chlorella was exposed to heavy metal ions for 12 or 24h, Fv/Fm and maximal fluorescence yield(Fm) changed in response to Hg2+ and Cu2+ based on image analysis. However, assessing quantitatively the toxic effects of several heavy metal ions is challenging.
        99.
        2015.11 KCI 등재 서비스 종료(열람 제한)
        however, these elements can limit plant growth. This study selected a heavy metal-tolerant plant by analyzing seed germination and biomass of alfalfa (Medicago sativa), canola (Brassica campestris subsp. napus var. nippo-oleifera), Chinese corn (Setaria italica), and a sorghum-sudangrass hybrid (Sorghum bicolor × S. sudanense), and determined heavy metal uptake capacity by analyzing biomass, chlorophyll a fluorescence, and heavy metal contents under high external copper or zinc levels. The seed germination rate and biomass of the sorghum-sudangrass hybrid were higher under copper or zinc stress compared to the other three plants. The plant biomass and photosynthetic pigment contents of the sorghum-sudangrass hybrid seedlings were less vulnerable under low levels of heavy metals (≤ 50 ppm copper or ≤ 400 ppm zinc). The maximum quantum yield of PSII (Fv/Fm) and the maximum primary yield of PSII (Fv/Fo) decreased with increasing copper or zinc levels. Under high copper levels, the decline in Fv/Fm was caused only by the decline in Fm, and was accompanied by an increase in non-photochemical quenching (NPQ). The Fv/Fm declined under high levels of zinc due to both a decrease in the maximum fluorescence (Fm) and an increase in the initial fluorescence (Fo), and this was accompanied by a marked decrease in photochemical quenching (qP), but not by an increase in NPQ. Accumulations of copper and zinc were found in both aboveand below-ground parts of plants, but were greater in the below-ground parts. The uptake capacity of the sorghum-sudangrass hybrid for copper and zinc reached 4459.1 mg/kg under 400 ppm copper and 9028.5 mg/kg under 1600 ppm zinc. Our results indicate that the sorghum-sudangrass hybrid contributes to the in situ phytoremediation of copper or zinc polluted soils due to its high biomass yield.
        100.
        2015.09 서비스 종료(열람 제한)
        Prognosis of the patients with lung cancer with lung-to-lung metastasis are known to be poor and frequently old aged persons with multiple nodules on imaging study abandon more invasive procedure including bronchoscopy and VATS (Videoassisted thoracoscopic surgery) to get tissue confirmation. Sjogren’s syndrome (SS) associated lung lesion mimicking lung cancer has a chance to have more favorable diseases including lymphoma. A 78-year-old woman with SS was admitted due to slowly progressive exertional dyspnea and multiple nodules on imaging study. She and her family gave up invasive diagnostic procedures at first due to old age but short term rapid change of dyspnea and nodules on chest CT brought out invasive procedures and diffuse large B-cell lymphoma was diagnosed. Dyspnea and nodules on imaging were improved after R-CHOP chemotherapy.
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