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        검색결과 65

        41.
        2010.04 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to investigate the actual conditions of radiation safety supervision in animal clinics using quality assurance (QA) and quality control (QC) of diagnostic X-ray units. The surveys for QA/QC, equipment condition, and safety supervision were carried out in 18 animal clinics randomly. The QA/QC included reproducibility of dose exposure, kVp, mAs, collimator accuracy test, collimator luminance test, X-ray view box luminance test, grounding system equipment test and external leakage current test. As a result, 44.44% of reproducibility of dose exposure was proper, 81. 25% of kVp test was good, and 100% of mAs test was appropriate. Also, 66.66% of collimator accuracy test was proper, 61.11% of collimator luminance test was good, 53.13% of X-ray view box luminance test was suitable. In addition, only 5.55% of grounding system equipment and ground resistance was proper, 63.64% of external leakage current test was appropriate in grounding system equipment test.
        4,000원
        43.
        2017.12 KCI 등재 서비스 종료(열람 제한)
        Spiral reinforcement in a circular column plays an effective role in the ductile behavior of a column through position fixing and buckling restraining of the longitudinal reinforcement, and confining core-concrete. Each country has suggested the minimum volumetric ratio of spiral reinforcement in order to secure the ductility of concrete columns. The minimum volumetric ratio of spiral reinforcement suggested by ACI 318-14 and the national concrete structure design standard was developed based on the theory of Richard et al. (1928); furthermore it has been used until now. However, their theory cannot consider the effects of high strength concrete and high strength reinforcement, and arrangement condition of the spiral reinforcement. In this study, a modified minimum volumetric ratio equation is suggested, which is required to improve the ductility of reinforced concrete circular columns and to recover their stress. The modified minimum volumetric ratio equation suggested here considers the effect of the compressive strength of concrete, the yield strength of spiral reinforcement, the cross sectional area of columns, the pitch of spiral reinforcements and the diameter of spiral reinforcement. In this paper, the validity of the minimum volumetric ratios from ACI 318-14 and this study was investigated and compared based on the results of uniaxial compression experiment for specimens in which the material strength and the spiral reinforcements ratio were used as variables. In the end of the study, the modification method for the suggested equation was examined.
        44.
        2015.11 KCI 등재 서비스 종료(열람 제한)
        In this study we were to explore the seasonal variation of water temperature distributions before and after weir construction at Gumi, Chilgok, Gangjung(Goryung), Dalsung in the Nakdong River using Landsat satellite images. Relationship between in-situ water temperature and radiance values of Landsat-5, 7, 8 satellite images showed high correlation. Seasonal variation of water temperature in Nakdong River showed that the fluctuation ranges of water temperature before weir construction were larger than those after weir construction. This indicated that the variation of water temperature is due to the difference of heat storage volume by weir construction and dredging work. In particular, the water temperature after weirs construction in autumn was 4-8 times lower than that before weirs construction. Water temperature after weir construction decreased in spring and summer at the downstream of Gumi weir and Gangjung(Goryung) weir, and the upstream of Dalsung weir. In autumn and winter, the water temperature after weir construction increased in the upstream and downstream of the whole weirs except upstream of Gumi weir. Relationship between water temperature and meteorological elements (air temperature, wind speed, sunshine, radiation) showed high correlation of above 94% in air temperature, and then radiation was high correlation before and after 65%.
        45.
        2015.07 서비스 종료(열람 제한)
        Cadmium (Cd) pollution is thought to be one of the leading threat to the environment due to its high toxicity. However, the molecular responses induced by Cd have so far been grossly overlooked. This study examines the morpho-physiological alterations combined with proteome changes in leaves of Sorghum bicolor when exposed to Cd. Ten days old sorghum seedlings were exposed to different concentrations (0, 100, and 150 μM) of CdCl2 and a significant accumulation of Cd in the leaves was recorded by ICP analysis. Furthermore, the effects of Cd exposure on protein expression patterns in S. Bicolor was investigated by two-dimensional gel electrophoresis (2-DE) and the 2-DE profile of leaf proteins from both control and Cd-treated seedlings were compared quantitatively using Progenesis SameSpot software. Results lined to morphological changes that plants treated with Cd suffered reduction of growth. The concentration of Cd was markedly reversed by the Cd treatments, whereas the absorption degree of Cd was increased by the higher concentration of Cd by confocal microscopy. Using 2-DE method, a total of 33 differentially expressed protein spots were identified by MALDI-TOF-TOF mass spectrometry. Of those, 13 protein spots were significantly enhanced/reduced while 20 reduced under Cd treatment. The most of the up-regulated proteins are involved in oxidative response, glutathione and sulfur metabolism as well as the secondary metabolite biosynthesis. Collectively, our study provides insights into the integrated molecular mechanisms of early responses to Cd and growth and physiological characteristics of sorghum seedlings hoping to provide references on the mechanism of heavy metal damaging plants.
        46.
        2015.07 서비스 종료(열람 제한)
        Copper (Cu) is an essential micronutrient required for growth and development of plants. But, at a high concentration in soil, copper acts as a major toxic element to plant cells due to its potential inhibitory effects against many physiological and biochemical processes. In this study, the morphological and physiological changes were observed in the leaf of sorghum plants treated with different concentrations (0, 100, and 150 μM) of Copper (Cu). The results linked to morphological changes that plants treated with Cu suffered reduction in growth and morphological changes. In the ion concentration investigation, the concentrations of Cu2+ increased, the concentration of others interacting ions (Zn2+, Ca2+, Mn2+, Fe2+) were changed dramatically. For proteome analysis, 2-D combined with MALDI-TOF-TOF mass spectrometry was performed. Two dimensional gels stained with silver staining, a total of 422 differential expressed proteins (≥ 2-fold) were identified using Progenesis SameSpot software. A total of 24 spots from Cu-induced sorghum leaf and 21 spots from Cu-induced sorghum root were analyzed by mass spectrometry. Out of 24 protein spots from Cu-stressed leaf, of which 16 protein spots were up-regulated and 8 protein spots were down-regulated whereas out of 21 protein spots, a total of 9 protein spots were up-regulated and 12 spots were down-regulated from Cu-stressed root. Taken together, these studies revealed the effects of heavy metal, Cu on the growth and physiological characteristics in sorghum seedlings and proteome investigation, hoping to provide references on the mechanism of heavy metal damaging plants.
        47.
        2014.11 KCI 등재 서비스 종료(열람 제한)
        이 논문은 고강도 콘크리트를 사용한 철근콘크리트 외부 보-기둥 접합부의 실험결과를 보고한 것이다. 실험체의 주요 실험변수는 접합부 파괴모드, 콘크리트 압축강도, 철근의 정착 방법이다. 모든 실험체는 ACI 352R-02 기준에 바탕을 두어 J파괴와 BJ파괴가 되도록 계획하였다. 주철근은 90도 표준갈고리로 하거나 확대머리철근으로 하였다. 실험결과는 콘크리트 압축강도에 제한되는 현행 ACI 설계 기준식이 고강도 콘크리트를 사용한 보-기둥 접합부의 강도를 다소 과소평가하고 있음을 보여준다. 또한 확대머리철근을 가진 J파괴형 보-기둥 접합부의 강도는 표준갈고리를 가진 접합부보다 약 10% 이상 높게 평가되었다.
        48.
        2014.10 KCI 등재 서비스 종료(열람 제한)
        In this research, chemical vapor deposition equipment built in the semiconductor·CVD (Chemical Vapor Deposition)process was introduced. Through polysulfone hollow fiber membranes under similar conditions to those of the actualprocess, conditions such as flow and pressure were used to observe the influence in order to separate and collect the SF6and CF4 substances. Results showed that as the retentate flow rate of the discharge unit increased and the residence timeto penetrate the membrane decreased, the emission concentration increased. As the pressure of the discharge unit increasedand the exhaust flow decreased, when the retentate flow rate was 10L/min, CF4 was shown to have a density of 4,963ppm, and it was 4,028ppm for SF6 the gas mixture had a concentration effect of three to four ratio. In addition, throughthe separation factor of fluorinated gases that arise in the actual process, the collection and concentration of SF6 and CF4were possible each gas’s recovery rate was higher than 99%.
        49.
        2014.07 서비스 종료(열람 제한)
        The different forms of flowers in a species have drawn thoughtful attention of many evolutionary botanists, including Charles Darwin. Common buckwheat (Fagopyrum esculentum Moench.) is regarded as a dimorphic self-incompatible plant which bears either a pin or a thrum flower. It is revealed that the S supergene the key element to govern the self-incompatibility, flower morphology, and pollen size. Already, we have produced self-incompatible buckwheat lines by an interspecific cross between F. esculentum and F. homotropicum by using embryo rescue. We also notice that the self-compatibility allele, Sh, keeps up the heteromorphic incompatibility. In the past decades, two dimensional gel electrophoresis based proteomics approaches have been applied systematically to identify and profile proteins expressed during pollen development of model plant species. Proteome techniques have vastly been applied in the fields of plant genetics, plant development, and plant physiology and ecology to reveal plant genetic diversity, plant development, differentiation of plant tissue and organ, separation and functional identification of novel component of various organelles, mechanisms of plant adapted to abiotic or biotic stresses including high temperature, low temperature, high salt, drought, and pathogens and insects, and interaction of plant with microbe. However, the plethora of studies related to heteromorphic has added remarkably to our knowledge in the field of the multiple aspects of the breeding system and many researches have provided evidence for the connection between these two components. But in spite of its potential biological significance, the high throughput proteomics analysis of this connection has so far been grossly overlooked. So our attempts are to unravel the proteome investigation in common buckwheat.
        50.
        2014.07 서비스 종료(열람 제한)
        Among the abiotic stresses, heavy metal (HM) toxicity is thought to be one of the major abiotic stresses leading to hazardous effects in plants. In spite of its potential physiological and economical significance, morphological alterations induced by heavy metals in plants have so far been grossly overlooked. In the present study, the morphological and physiological changes were observed in the leaf of sorghum plants treated with different concentrations (0, 50, 100, and 150 μM) of CdCl2. Results revealed that plants endured reduction in growth and morphological changes amazingly altered by cadmium. The growth of sorghum seedlings treated with 150 μM cadmium was more inhibited than that of sorghum seedlings treated with 100 μM Cd, 50μM and non-treated plants. The morphological characteristics revealed that the cadmium stress inhibited the root and shoot elongation after growing the rise seedling in the presence of cadmium. In the case of ion concentration, the concentrations of Zn2+, Ca2+ were decreased whereas Fe2+ concentration was increased except 100 μM under cadmium stress. In confocal microscopy, results showed that the absorption degree of cadmium was increased by the higher concentration of cadmium. The fluorescence intensity of cadmium was also increased. Thus, it seemed that cadmium has an influence on sorghum in the case of early stages of sorghum. This study reported the effects of heavy metal, cadmium on the growth and physiological characteristics of sorghum seedlings, hoping to provide references on the mechanism of heavy metal damaging plants, and phyto-remediation for heavy metal polluted soil.
        51.
        2014.06 KCI 등재 서비스 종료(열람 제한)
        This study was investigate the influences of wild haw (Crataegus pinnatifida BUNGE) on lowering blood urea nitrogen (BUN) and creatinine concentrations in dyslipidemic rats. Four groups of rats were fed different diets for 5 weeks: basal diet (BD group), nondyslipidemic diet+feral haw extract (NDF group), dyslipidemic diet (DLD group), dyslipidemic diet+feral haw extract (DFH group). BUN, creatinine and uric acid concentrations were significantly higher in the DLD group than in the BD group. However, DFH group significantly lowered BUN, creatinine and uric acid concentrations compared to the DLD group. Amylase activity was significantly lower in the DLD group than in the BD group, while DFH group significantly higher compared to the DLD group. Lipase activity was also also significantly lower in the DLD group than the other group. Accordingly, these results suggest that haw extract could be effective for improving kidney function in dyslipidemic rats.
        52.
        2014.05 KCI 등재 서비스 종료(열람 제한)
        The purpose of this study was to improve low digestibility in anaerobic digestion facility of the sewage treatment plant. To perform this research, sludge digestion and digestion gas purification facilities in sewage treatment plant was applied. In the result of this study, it was very effective for sludge reduction from the improvement of digestive efficiency. In addition, it was confirmed that high purity CH4 (methane) was produced. This results can be useful as basic data to improve the low digestibility in anaerobic digestion processes.
        53.
        2014.03 KCI 등재 서비스 종료(열람 제한)
        This research was conducted to configure an optimal membrane module system that would selectively separatehazardous gases which are emitted during the processes in the semiconductor industry. In order to identify the most integralcharacteristic results, a numerical analysis formula which incorporates the dimensions of pipe diameter and gas flow ratewas utilized. Based on the results of the numerical analysis formula, a prototype designed with the main pipe being 100Awith gas outlets made with identical diameter thickness to the main pipe, set at equal intervals, was built. When the gasflow rate is set at 100L/min, although the processing outlets 1, 2, and 3 showed 0.03m/sec deviations in the rate ofspeed, when considering the variables of the average flow rate, the same emission rates are noted. However, in the instanceof when the overall prototype pipe dimensions was enlarged to 200A and the gas flow rate was increased to 500L/min,there was better stabilization. Therefore concluding that as the pressure rates flowing in the main pipe increases, morestable characteristics at the gas outlets can be found.
        54.
        2014.03 KCI 등재 서비스 종료(열람 제한)
        이 연구에서는 고로슬래그 미분말을 사용한 프리캐스트 보의 전단성능에 대하여 평가하였다. 실험체는 고로슬래그 미분말 치환율에 따라 총 4체의 실험체를 제작하였다. 모든 실험체는 전단경간비 2.5, 보의 폭 200mm, 유효깊이 300mm이며, 3점 가력을 받는 단순보로 계획하였다. 또한 이 연구에서는 실험체의 전단강도를 예측하기 위하여 기존 전단강도 예측식을 이용하여 실험결과와 비교하였으며, 총 89개의 기존 전단 실험결과를 이용하여 실험결과와 비교 분석하였다. 실험결과, 고로슬래그 미분말을 치환한 실험체는 포틀랜드 시멘트만을 사용한 실험체와 비교분석한 결과 유사한 전단성능을 나타내었다.
        55.
        2013.12 KCI 등재 서비스 종료(열람 제한)
        We investigated the spatial and temporal variations of phytoplankton in Youngil Bay as well as the effect of water physico-chemical parameters. Water samples at three stations were collected and measured monthly from May to November in 2010. The taxa of phytoplankton observed in this study were classified as 33 Bacillariophyceae, 23 Dinophyceae, 1 Euglenophyceae, 2 Crysophyceae and 1 Cryptophyceae. The highest biomass of phytoplankton was observed at inner station in September, which was characterized high concentration of dissolved inorganic phosphate(DIP) in surface water after rainfall. Nutrient concentrations, chlorophyll-a and phytoplankton biomass values showed the marked trend to decrease from the inner bay to the outer bay. Pearson's correlation co-efficient between salinity and other water parameters including chlorophyll-a, pH and DIP showed the strong negative relationship r=-0.82, r=-0.78 and r=-0.75 (p<0.01), respectively. These results indicate that the water quality of Youngil Bay could be stimulated by nutrient enriched input from Hyeogsan River discharge, and the spatial and temporal distribution of phytoplankton biomass principally limited to DIP concentration from Hyeogsan river.
        56.
        2013.10 KCI 등재 서비스 종료(열람 제한)
        In this study, we estimate the interannual spatial and temporal distributions of fishing grounds at night in the East Sea based on satellite and in-situ data. We observe that the 15℃ thermal front moves in the north-south direction according to the movement of the warm water (above 18℃) in the Tsushima Warm Current (TWC) area, forcing the cold water area (below 10℃) to either expand or shrink. The interannual variations of sea surface temperature (SST) in winter represented by the indicator SST of 6℃ are consistent with the east-west zonal areas in the central East Sea which represented over 1℃ standard deviation of SST in February during 1990-2000. Annual SST in the fishing grounds of common squid fishing vessels, observed both by fishing vessels and satellites range from 9-22℃, with the satellite-observed data having a larger range than the fishing vessel-based ones. The interannual distributions of the common squid fishing grounds in the East Sea are mostly concentrated in the TWC area in the southwestern part of the East Sea and in the coast of southern Honshu and Hokkaido in Japan. The interannual distributions of the nighttime fishing vessels are consistent with the catches investigated from the fishing vessel.
        57.
        2012.11 KCI 등재 서비스 종료(열람 제한)
        The purpose of this study is to analyze seasonal variations of seaweed community structure according to ocean environment at three areas in the east coast of Korea. Mean water temperatures of Gosung, Samchuk, and Gyeongju were 8.3℃, 11.2℃, and 13.1℃, respectively, during the growing winter season of 2011. Subtidal benthic macroalgal flora and community structure were investigated at the sites between February to November 2011. The numbers of seaweed species at the areas were 38, 12, and 15, respectively. The amounts of biomass were 7.35 kg m-2, 1.80 kg m-2, and 0.84 kg m-2, respectively, during the period. The values of C/P, R/P, and (R+C)/P representing flora characteristics at Sokcho area were 0.1, 1.1, and 1.2, respectively. The values of flora characteristics at Samchuk were 0.3, 0.6, and 1.0, respectively. The values of flora characteristics at Gyeongju were 0.4, 4.0, and 1.2, respectively
        58.
        2012.02 KCI 등재 서비스 종료(열람 제한)
        Climatological trend for the period of 1970 to 2009 in sea water temperature around the Antarctic Peninsular waters in the Southern Ocean was investigated. During the period from 1970 to 2009, sea water temperature in the top 500 m water column except 100 m increased at a rate of 0.003 - 0.011℃·yr-1, but at 100 m it decreased at a rate of -0.003℃·yr-1. Although long-term trend is generally warming, there were several periods of sharp changes between 1970 and 2009. Annual mean sea water temperature between surface and 500 m except 100 m decreased from the early of 1970s to the end of 1980s, and then it increased to the end of 2000s. In the entire water column between the surface and 500 m, sea water temperature closely correlated with the El Nino events expressed as the Southern Oscillation Index(SOI), and SOI and sea water temperature have a dominant period of about 3-5 years and decade.
        59.
        2011.11 KCI 등재 서비스 종료(열람 제한)
        Time-series change in Gyeongpo beach shoreline was illustrated using DGPS(Differential Global Positioning System, resolution < 0.6m) observation from April, 2009 to April, 2010. The shoreline was subdivided into 12 areas, and westward and eastward movement of shoreline position at each area was calculated. In general, the shoreline moved toward sea during summer, and it moved toward land during winter. The southern and northern part of the shoreline had different pattern in time-series. The shoreline in the southern part moved toward sea during summer and moved toward land during winter, but time-series pattern of the shoreline in the northern part was more complicated than that in the southern part. Pattern of time-series change in the northern part was made up of three different types; the first is that the shoreline moves continuously toward land, and the second thing is that the shoreline's movement is the opposite to the southern part, and the third thing is that the shoreline maintains a state of equilibrium without any great fluctuation. The total length of the shoreline was the largest during winter and the smallest during summer. In general, time-series change in the shoreline had positive(+) relationship with sea surface pressure and wind speed.
        60.
        2010.03 KCI 등재 서비스 종료(열람 제한)
        The present study explores time and spatial thermal environment for Daegu, which is a city built on a basin area, according to varying land cover conditions of the earth's surface by analyzing data derived from meteorological observation and satellite images. The study has classified land use by utilizing MODIS satellite images and analyzed land surface temperature. Also, by using data acquired from automatic weather system, the study has evaluated the effects of atmospheric heating caused by city pavements by analyzing the sensible heat flux between the city's land surface and the atmosphere.The results are as follows. 1) Classification of land use in the Daegu area shows 46.64% of urban and built-up area, 1.39% of watersides, 35.19% of forest, 11.43% of crops, and 5.37% grasslands. 2) During the weekdays throughout the year, the land surface temperature was high for Dalseogu, Bukgu, and Seogu regions where industrial complexes could be found. Comparatively, lower temperature could be observed in the woodlands. 3) While the land surface temperature displayed the effects of pushing air upwards during the weekdays in urban areas, the reverse was true for forest regions. During the night, the temperature did not exert any significant influence on air movement.
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