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        검색결과 1,376

        801.
        2017.05 서비스 종료(열람 제한)
        Background : To select plant resources of the possibility of development as a natural antioxidant, the antioxidant activities including total polyphenol content (TPC), 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS), 2,2-diphenyl-1-picryl-hydrazil (DPPH), ferric reducing antioxidant power (FRAP) and reducing power (RP) of perilla accessions collected from South Korea were conducted. Method and Results : A total of 18 perilla accessions by regions were selected. Two grams of dried perilla leaves were extracted with 85% ethanol and used for analysis of antioxidant activity. Antioxidant activity value was measured in a spectrophotometer. Perilla extracts showed variation in TPC ranging from 30.87 to 92.66 ㎍ GAE ㎎-1 dw. ABTS, DPPH, FRAP and RP ranged from 6.83 to 38.64 ㎍ Trolox ㎎-1 dw, 0.63 to 8.62 ㎍ ASC ㎎-1 dw, 5.05 to 17.57 ㎍ ASC ㎎-1 dw, and 4.52 to 35.69 ㎍ ASC ㎎-1 dw, respectively. TPC was high in perilla leaves of Gyeongsang-do, but other antioxidant activities were high in perilla leaves of Chungcheong-do. Cluster analysis based on antioxidant acitivities of 18 perilla accessions consist of group Ⅰ (3 accessions), Ⅱ (2 accessions), Ⅲ (5 accessions) and Ⅳ (8 accessions). Group Ⅱ characterized as higher antioxidant activities than other groups. Principal component analysis (PCA) based on antioxidant data revealed that the first two principal components (PC1 and PC2) together explained 97.78 % total variation. Conclusion : IT242410 and IT235354 of group Ⅱ showed high antioxidant activity. These resources will be useful for developing natural antioxidants.
        802.
        2017.04 서비스 종료(열람 제한)
        Tributary area based-lumped mass model is a simplified modeling technique and it is popularly adopted in earthquake engineering for the evaluation of seismic performance of structures. However, the technique provides somewhat less accuracy due to its different frequencies and mode shapes, compared to the detailed FE model. For the basic understanding this study investigates the sensitivity of the lumped mass locations on the mode shapes and modal participation factors, considering a cantilever typed column structure.
        803.
        2017.03 KCI 등재 서비스 종료(열람 제한)
        우리나라는 지난 30년 동안 기후변화 및 도시화 등으로 인한 변화가 급격하게 진행된 바 있으므로, 두 가지 요소들로 인한 유량의 변동량을 정량화 하여 분석할 필요가 있다. 그러나 유량의 변동량을 특정 원인별로 구분하여 분석하고자 하는 국내 연구는 매우 미미한 형편이며, 다양한 시간단위 를 이용한 원인별 유량 변동량의 산정에 관한 연구는 더욱 찾아보기 힘들다. 따라서 본 연구에서는 기후변화 및 인간활동으로 인한 유량 변동량을 정량적으로 분리하기 위하여 수문모형을 이용한 방법과 수문학적 민감도(hydrological sensitivity) 분석 방법을 소양강 상류유역 및 섬강 유역에 대해 적용하고 유량 변동량의 결과를 월별, 분기별 및 연별로 구분하여 제시하였다. 인간활동으로 인해 발생되는 급진적인 변동점을 탐색하기 위해 이중누가곡선, Pettitt 검정 및 베이지안 변동점(Bayesian change point) 분석을 시행하였으며, 탐색된 변동점을 활용하여 변동점 이전 구간에 대 해 보정 및 검증된 SWAT모형과 6가지의 Budyko 곡선 함수들로부터 각각 유량 변동량을 산정하여 수문모형에 의한 유량 변동량을 검증하였다.
        804.
        2017.01 KCI 등재 서비스 종료(열람 제한)
        We analyzed the variation in occurrence time and intensity of attacks by the rice stem borer (Chilo suppressalis Walker) on several crops. This study aimed to understand how C. suppressalis damages crops and to utilize this basic data for the establishment of environment-friendly control methods like pheromone traps. This study surveyed the changes in occurrence patterns of C. suppressalis, biological characteristics of overwintering larvae, and the efficacy of different types of pheromone traps the years. We found similar occurrence patterns of C. suppressalis in different crops. In addition, occurrence time of the first generation was advanced. Overwintering larvae showed no difference in pupal period and weight compared to the non-overwintering ones. However, the larval period was reduced to 19.1 days in Miscanthus field, in contrast to that in the paddy fields. It was confirmed that larvae of C. suppressalis generally prefer the lower part of the stems of Miscanthus. Efficiency of the emergence trap was confirmed to be greater than that of the delta trap for capturing C. suppressalis adults. However, it is necessary to adjust the control period because of the advancement in occurring time of C. suppressalis in recent years. The larvae of C. suppressalis experience favorable environmental conditions for overwintering in Miscanthus fields. The major Miscanthus fields are generally located in the areas protected for sources of drinking water, owing to which spraying of chemical pesticides is very limited. The results of this study provide important inputs for the development of environment-friendly control methods.
        805.
        2016.12 KCI 등재 서비스 종료(열람 제한)
        Lettuce is an important annual leafy vegetable and bitterness is its potent flavor character. Lettuce germplasm differ their phenotypic characters and sesquiterpene lactones (SLs) contents which are important for consumer’s acceptance. This study was carried out to evaluate the phenotypic characters and SLs contents in one hundred lettuce germplasm in Jeonju, Korea. Twenty-three agro-morphological (16 qualitative and 7 quantitative) traits and two SLs (lactucin and lactucopicrin) contents were studied in these germplasm. Germplasm exhibited the variation in qualitative and quantitative characters. Average plant weight was 423.9 g with a range from 116.0 to 905.0 g. Lactucin content was varied from 19.7 (IT 294226) to 194.4 ㎍/g (IT 294298) with an average concentration of 84.7 ㎍/g. Lactucopicrin ranged from 82.5 (IT 300134) to 2228.6 ㎍/g (IT 294210) with an average concentration of 586.3 ㎍/g. Total SLs content was ranged from 120.1 (IT 300134) to 2286.6 (IT 294210) ㎍/g with the average concentration of 671.0 ㎍/g. Significant (p≤0.05) differences were found between crisp head and butter head germplasm for lactucin, lactucopicrin and total SLs content. Crisp head germplasm revealed the highest average lactucin (112.9 ㎍/g), lactucopicrin (734.8 ㎍/g) and total SLs content (847.7 ㎍/g). Crisp head and leafy type germplasm exhibited more total SLs content (847.7 and 744.7 ㎍/g, respectively) than cos (524.9 ㎍/g) and butter head type (519.4 ㎍/g). Principal component analyses of the quantitative traits indicated that the first principal component axis accounted more than 91% of the total variation. This study revealed the ample genetic variation in the agro-morphological traits and SLs contents to support the selection for improved lettuce varieties.
        806.
        2016.12 KCI 등재 서비스 종료(열람 제한)
        일반적으로 배사에 비해서 준설은 경제적 부담이 크기 때문에 배사를 효율적으로 운영하는 것이 중요하다. 본 연구에서는 2차원 하상변동 모형 인 Nays2DH를 이용하여 홍수기 운영수위에 따른 배사효율을 낙동강에 위치한 달성보를 중심으로 분석하였다. 분석결과, 가동보의 수 만큼 배사 수로가 형성되었으며, 배사수로 상류에는 퇴적이 발생하는 것으로 나타났다. 또한, 홍수기 운영수위를 EL. 14.5 m로 운영하는 것이 EL. 14.0 m로 운영하는 것에 비해서 배사효율이 약 4.6% 증가하여 퇴사가 약 4.5% 감소하는 것으로 나타났다. 본 연구에서 분석한 홍수기 운영수위에 따른 배 사효율의 변화를 고려한다면, 저수지 퇴사 저감 및 준설주기의 장기화가 가능할 것으로 판단된
        807.
        2016.10 서비스 종료(열람 제한)
        Background : Angelica dahurica Bentham et Hooker, Angelica gigas Nakai, Ostericum koreanum Maximowicz and Peucedanum japonicum Thumberg are a major medicinal plant in north Geungbuk province. Using medicinal plants are impotant it`s ingredient. Dry condition and stroage method are not standard manual. The ingredient variation of dry condition and stroage method were not researched. Methods and Results : Using plant material were cutivated on Gyongsangbukdo Bonghwa area. It were studied ingredient variation after dry and storage condition by HPLC methods. Major ingredient of Angelica gigas Nakai are decurusin, decurusinangelate. Heated air bulk dry get more decursin than natuarl dry and decurusinangelate of natural bulk dry was higher than heated air bulk dry. Major ingredient of Ostericum koreanum Maximowicz are imperatorin and isoimperatorin.. Imperatorin of Ostericum koreanum was highest peak on 50℃ heated-air dry after plastic bag sorage and isoimperatorin was highest peak on 40℃ heated-air dry after mountain cultivation. Imperatorin is a major ingredient Angelica dahurica Bentham et Hooker. Heated air bulk dry get more decursin and decursinangelate than natuarl dry and small heated-air dry. Peucedanol-7o_glucoside is a major ingredient Peucedanum japonicum Thumberg. Natural bulk dry get more peucedanol-7o_glucoside than heated-air bulk dry. Conclusion : Ingredient of Angelica dahurica Bentham et Hooker, Angelica gigas Nakai, Ostericum koreanum Maximowicz are different under various cutivation, drying method, storage. Diffent Ingedients of Angelica gigas Nakai, Ostericum koreanum Maximowicz were not accord it’s optical conditon.
        808.
        2016.10 서비스 종료(열람 제한)
        Background : Yellowhorn (Xanthoceras sorbifolium Bunge) is distributed in northeastern region in China. The seeds are oil-rich and used as an edible and/or medicinal additives in China. We investigated genetic indices and molecular variance using ISSR markers and oil contents variance by analyzing fatty acid composition in several artificial populations in China. Methods and Results : Seeds were collected from four discontiguous artificial populations in four area in China : two in Inner Mongolia (IM), one in Liaoning (LN) and one in Shandong (SD). Farm in SD showed the highest number of effective alleles (Ne), Shannon index (I), and expected heterozygosity (He), i.e., 1.598, 0.470, and 0.325, respectively. Crude fat contents in kernel observed as 54.5 g 100 g-1 from SD. In contrast it was observed the lowest contents as 46.5 g 100 g-1 from LN . The fatty acid composition was determined to those of oleic acid (31.3%) from SD. And linoleic acid was determined as 38.1% from LN. These artificial populations have relatively high genetic variation, and within-population variation (23%) was higher than among populations. The artificial populations were divided into two groups, revealing these was little correlation between genetic and geographic distance. Conclusion : This study can provide the important information on genetic variation and contents characteristics. It may be responsible for the programs of improvement and germplasm conservation in the future.
        809.
        2016.10 서비스 종료(열람 제한)
        High-strength bolt has high stiffness and fatigue strength. At this time, initial axial force is one of main factor to affect the strength and deformation behavior of connection. Therefore, the objective of this study is to investigate reduction of initial axial force in high-strength bolt under shear fatigue.
        810.
        2016.10 서비스 종료(열람 제한)
        Current bridge load carrying capacity evaluation method requires FE model and field test to get the dynamic response. This paper shows a economic and convenient technique to trace the variation of the load carrying capacity of bridges, based on fundamental frequency measured under actual traffic flow.
        811.
        2016.09 KCI 등재 서비스 종료(열람 제한)
        The effects of weather variations on winter hulless barley were analyzed using data obtained from winter crop situation test at Iksan from 1985 to 2015. The wintering stage in the 16 years from 2000 to 2015 has become colder and shorter than that in the previous 15 years from 1985 to 1999. This has resulted in an early sequence of regrowth date, heading date, and ripening date. Heading date of hulless barley was mostly influenced by regrowth date and period of stem elongation. Futher, the regrowth date and period of stem elongation were strongly negatively correlated with the average air temperature in February and the maximum air temperature in March, respectively. The number of spikes per m2 and 1000-grain weight of Saechalssal cultivated from 2003 to 2015 showed strong positive correlations with yield. In early heading years, yield increased with extended ripening period and with increased 1000-grain weight. There was a strong negative correlation between 1000-grain weight and the average temperature during the ripening period. In the 15 years from 1985 to 1999, warm winters contributed to yield increase with increase in the number of spikes per m2 and a long ripening period. In contrast, in the recent 16 years from 2000 to 2015, the large variability in air temperature during the wintering stage, the decreasing number of spikes per m2 and the steadily increasing air temperature and decreasing precipitation during the ripening stage have caused high temperature stress and yield loss in late heading years.
        812.
        2016.08 KCI 등재 서비스 종료(열람 제한)
        The heat budget is investigated in the Gumi Reservoir of the Nakdong river. In warm climate season, solar radiation effects play a important role in the change of water temperature. The features of the surface heat balance are almost derived by the latent heat flux and the solar radiation flux. On the other hand, in cold climate season, change of heat stored in the water is mainly dominated by latent and sensible heat transfer between water and air, since flux of solar radiation and loss of outgoing long wave radiation balance approximately. For the annual averages, net flux of radiation, evaporation(latent heat) loss are dominant in the Gumi reservoir. The evaporation losses are dominant from spring to early winter. This means that the Gumi reservoir rolls like a lake of thermal medium or deep depth.
        813.
        2016.05 서비스 종료(열람 제한)
        Background : The ginseng cool-season and semi-shade plant undergoes photosynthesis smoothly at low temperature in the morning but its efficiency falls at high temperature in the afternoon. Therefore, if it is possible to control light transmission rates (LTR) every day, it will be able to draw an ideal result in the ginseng growth by attracting a lot of lights before 11am and attracting few lights after 11am which is the affect point of the photosynthetic efficiency. Methods and Results : While installing the sun shading facility that could control the light environment based on 11am and surveying the ginseng's growth and photosynthetic characteristics. The photosynthetic efficiency increased 2.81 times compared to conventional practices without the change of the chlorophyll content although LTR was high because of the low temperature in the morning. The aboveground part growth of the ginseng which adapted to the light environment increased to influence the root weight, when the ginseng was 4 years old, the fresh root weight was averagely 33.3g per plant which increased by 81% than 18.4g of conventional practices. Conclusion : If the light environment management according with the photosynthetic nature of the ginseng is conducted based on 11am, it will be possible to produce a large capacity and excellent-quality ginseng.
        814.
        2016.05 서비스 종료(열람 제한)
        Background : The roots of Curcuma longa Radix is used to make herbal medicine, which is registrated in the Korean Pharmacopoeia. This species is a perennial herb, and is distributed throughout tropical and/or sub tropical regions. High temperature and humidity with small difference between daytime and nighttime is the finest environment condition in this species. Recently, demand for C. longa has been expanded to cultivation area as central region from southern region. Therefore, this study aimed to investigate the effect of harvest time on the growth, yield characteristics and main composition contents in C. longa. Methods and Results : Curcuma longa rhizomes were harvested from farmland in Jindo, Jeollanam-do in end October, early November, middle November, end November, early December, middle December and end December 2015. Harvested rhizome were dried in hot air drier, and it was investigated as growth characteristics and yield. Contents of curcumin, demethoxycurcumin, bisdemethoxycurcumin was analyzed from dried powder of rhizome. The analysis column was used to Phenomenex, Kinetex 2.6um F5 100A 100*2.1mm. 10 mg of standard was taken, 80% MeOH was added to dissolve in 10 ㎖ flask. 0.5, 1, 2, 4 ㎖ was taken from dissolved solution and then was added to 10 ㎖ of 80% MeOH. It was filtered through 0.45 ㎛ filter and then 5 μℓ was taken to make standard solution. Analytical calibration curve was measured to diluted solution within sample concentration. 2 g of ground sample was taken, 40㎖ of 80% MeOH was added to extract by ultrasound sonication during 60 minutes and then it was filtered through 0.2 ㎛ filter to analyze component content. Conclusion : The root weight significantly increased from 376.1 g in end October to 695.9 g in end December as 1.8 double. Curcumin contents differed significantly among harvest times in end November and early December. Demethoxycurcumin increased from early November to end November, and Bisdemethoxycurcumin increased to the early November.
        815.
        2016.04 KCI 등재 서비스 종료(열람 제한)
        본 연구는 고 에너지 방사선 조사에 기인된 방사선치료실 내 오존 농도의 변화를 비교·분석하고자 하였 다. 이를 위하여 치료실 주변 대기 중 오존 농도와 치료실 내 배경 오존 농도를 분석하여 고 에너지 방사선 조사에 기인된 치료실 내 평균 오존 농도를 비교하였다. 치료실 내 배경 오존 농도는 평균 17.4±7.9ppb로 방사선치료실 주변의 대기 중 오존 농도(평균 36.8±22.3ppb)보다 약 50% 정도 통계적으로 유의하게 낮게 나타났다(p<0.05). 고 에너지 방사선 조사에 기인된 치료실 내 오존 농도는 방사선이 조사됨과 동시에 배경 오존 농도의 약 2배 수준으로 급격하게 증가되었으며 조사시간이 증가함에 따라 기울기가 일정한 증가 추 이를 보이다가 약 130초에서 180초 부근에서 최대 오존 농도를 이루고 점차 포화되는 경향을 보였으며 배 경 오존 농도로 감소하는데 소요되는 시간은 약 10분 이상이었다. 본 연구 결과를 토대로 고 에너지 방사 선 조사에 기인된 방사선치료실 내 오존 농도는 후각을 자극하는 오존의 특이한 냄새를 맡거나 순간적인 호흡 곤란과 마른기침으로 가슴 통증 등의 신체적 증상이 나타날 수 있는 수준으로 밀폐된 방사선치료실 에서 고농도 오존에 장시간 노출될 경우 폐 질환을 악화시킬 수 있기 때문에 각별한 주의가 요구된다.
        816.
        2016.04 KCI 등재 서비스 종료(열람 제한)
        Background: This study aimed to investigate the effect of harvest time on the growth, yield characteristics and loganin content in Dipsacus asperoides Wall. Methods and Results: Dipsacus asperoides seedlings were planted within a nursery environment in early May 2015 and harvested in early, middle and late October 2015, and early November 2015. Harvest time did not result significant differences in the plant height, stem diameter, branch length, leaf width and aboveground dry weight moreover, no significant differences were observed in root length, number of roots and root diameter. However, the diameter of lateral roots was greater in the harvests from the late October and period thereafter. The highest values of root dry weight and yield were recorded in early November. Specifically, the yield significantly increased from 205 ㎏/10 a (index: 100) in early October to 358 ㎏/10 a (index: 175) in early November, in terms of root part weight. Loganin contents of D. asperoides differed significantly among harvest times raging from 0.0766% in early October to 0.1704% in late November, thereby showing an increasing trend in later harvest times. Conclusions: These results suggest that the optimum harvest time for D. asperoides is early November, when the yield is the highest. Harvest time significantly affected loganin contents, which constantly increased from early October until early November.
        817.
        2016.04 서비스 종료(열람 제한)
        In this study, the heat insulating performance increase the indoor temperature of the building is applied to the concrete was compared with plain concrete. As a result, the indoor surface at the outside temperature of 4.69∼7.32 ℃ temperature conditions showed a difference of up to 1.10 ℃, the lowest 0.54 ℃, indoor temperature is up to 0.95 ℃, 0.63 ℃ lower results showed a minimum.
        818.
        2016.04 서비스 종료(열람 제한)
        Because stage cable-bridge have long spans and large members, their movements and geometrical changes by temperatures tend to be bigger than those of small or medium-size bridge. Therefore, it is important for maintenance engineers to monitor and assess the effect to temperature on the cable-supported bridges. To evaluate how much the superstructure expands or contracts when subjected to changes in temperature is the first step for the maintenance. Thermal movements of a cable-stayed bridge in service are evaluated by using long-term temperatures and displacements data.
        819.
        2016.04 서비스 종료(열람 제한)
        It is to confirm the various causes for cracks in concrete lining and understand the reasons for major cracks by analyzing on-site constructional conditions. Also, it is to identify the bahavior of concrete lining for its main cause of cracks.
        820.
        2016.02 KCI 등재 서비스 종료(열람 제한)
        In this study, changes in daily temperature range were investigated using daily maximum and minimum temperatures of Busan and Daegu for last 81 years (1934-2014), and also characteristics of daily temperature range and seasonal fluctuations by urbanization were examined. First, elapsing changes showed a lower decreasing trend in Busan (0.32℃) than Daegu (1.2 8℃) for last 81 years. Daily temperature range showed the highest rise in winter in both Busan and Daegu. Second, daily temperature range due to urbanization showed that Busan had a pronounced decreasing trend before urbanization meanwhile Daegu showed the same trend after urbanization. On seasonal changes, the results of Busan showed a decreasing trend in summer before urbanization, and in autumn after urbanization. For Daegu, the results showed a decreasing trend in spring before urbanization, and in winter after urbanization. Seasonal fluctuations of Busan showed little difference in the pre and post-urbanization, except in winter and summer. There was large difference in daily temperature range in winter after urbanization, and in summer before the urbanization. The results in Daegu showed that there was decreasing trend of daily temperature range in all seasons after urbanization.