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        검색결과 634

        424.
        2016.05 서비스 종료(열람 제한)
        Background : Aralia cordata and Polygonum multiflorum GAP cultivation requires a stable drying and storage settings after harvesting. therefore, this experiment was performed in order to effectively manage the physical, chemical and biological hazards. Methods and Results : Test materials were used biennial Aralia cordata, Polygonum multiflorum harvested from the medicinal testing ground. The drying temperatures were treated with 40, 50, 6 0℃ and natural drying. Storage containers were stored in plastic boxes, styrofoam boxes and kraft paper containers, examined the color and quality changes for eight months. Aralia cordata and Polygonum multiflorum drying temperature is dry it took natural drying 720 hours, 40℃ hot air drying 180 hours, 50℃ hot air drying 168 hours and 60℃ hot air drying 108 hours. However, the difference chromaticity of the Lab value corresponding to the temperature does not appear, it was good to dry in a short time at 60℃. Aralia cordata and Polygonum multiflorum stored in a styrofoam box storage method but can be stored at room temperature for up to four months, began to decay caused by moisture content it continues to increase. In plastic box in case of Aralia cordata and kraft vessel in case of Polygonum multiflorum can be stored for eight months in room temperature without decay. Styrofoam boxes stored at 5℃ cold storage were higher water absorption such as room temperature, but decay did not occur. Plastic box and styrofoam box were a tendency such as room temperature. Conclusion : Aralia cordata and Polygonum multiflorum are thought that the color change is not large depending on the drying temperature the lower the water content. Styrofoam storage box, the air permeability is higher than plastic boxes and containers Kraft vessel, decay occurs expected increase.
        425.
        2016.04 서비스 종료(열람 제한)
        The purpose of this study was to investigate deformation and reduction of initial clamping force in slip critical type connection under fatigue loading. And, the parameters of this study were the different clamping force and friction coefficient of surface of plate. As a result, the clamping force of all specimens were generally decreased in comparison with initial values under fatigue loading.
        426.
        2016.04 서비스 종료(열람 제한)
        Accelerated alkali resistance test were conducted for pre-heated GFRP Rebar. The GFRP rebar specimens were heated to temperatures of 60℃, 120℃, 200℃ and 300℃ and then immerged in alkali solution for 30days. According to ACI 440.3R-12, tensile properties were measured.
        427.
        2016.04 서비스 종료(열람 제한)
        This study focused on whether the large-scale expansion joints of the Diamond Bridge, a suspension bridge, is being appropriately and efficiently utilized during maintenance period. In this study, a linear regression model was developed by analyzing long-term monitoring data from the bridge, considering the bridge design standards in Korea and building-related literatures. Then, the reliability of the model was verified through a theoretical review on the relationship between temperature change and expansion joint displacement. The expansion joint displacements of the bridge showed a regular time series graph with temperature change. A linear regression analysis indicated that the slope of the graph was very similar to the displacement of steel due to linear expansion coefficient, with a high determination coefficient (R2=0.979), meaning that the actual behavior of the bridge conforms to the theory. Considering the expansion joint specification of the bridge and existing external loads, actual expansion joint displacement was only 8.5 percent of its specification, so the specification can be adjusted in order that actual expansion joint displacement can be up to 21.6 percent of its specification. In this case, expansion joint cost can be reduced as much as 78.4 percent of its original cost.
        428.
        2016.04 서비스 종료(열람 제한)
        In this study, the behavior of the existing tunnel was measured by automation system to analyze the characteristics of lining longitudinal cracks. The characteristic of the infusion material which it is applicable to crack repairing was considered by grasping the overall behavior including the temperature and the crack width change, and etc., From this, the reasonable repair period for the complement efficiency enhancement was trying to be determined.
        429.
        2016.04 서비스 종료(열람 제한)
        Recently, there are increasing cases utilizing the composite slab with a deck-plate for the simplicity of construction process and shortening of the construction period by eliminating the formwork and reinforcement placing works. General method of an existing deck-plate slab places welded wire fabric(w.w.f) for the crack control by drying shrinkage, however it was pointed out as its potential possibility for a number of cracks. In this study, long-term cracking behavior of deck-plate slab with the steel fiber was evaluated on the continuous two-span slab specimens that was designed on the general building loading condition.
        430.
        2016.03 KCI 등재 서비스 종료(열람 제한)
        A long-term field experiment under different fertilization treatments had been conducted to explore the effects of rice yield and soil chemical properties from 1978 to 2008 in Suwon, Korea. The paddy was applied eight fertilization treatments which were F0 (no fertilizer), PK (phosphorous and potassium), NK (nitrogen and potassium), NP (nitrogen and phosphorous), NPK (nitrogen, phosphorus and potassium), NPKC (NPK with compost), NPKS (NPK with straw) and NPKL (NPK with lime). Results of 31 years experiment showed that yield index (the ratio of yield in each treatment to NPK) was the lowest in F0 (0.52) and the highest in NPKC (1.18). Yield index was gradually increased in NPKC but decreased in F0 and NK. The yield index of PK, NP, NPKS and NPKL were not changed long-term treatment. Soil acidity of NPKL showed the highest with pH 7.9, and that of other treatments ranged from pH 6.3 to 6.8. Available phosphorous content of soil was increased in all plots by long-term fertilization, was the highest in PK and NPKC. Soil organic matter was higher in NPKC (1.8%) and NPKS (1.8%) than other treatments (1.3~1.4%) in the early experiment, but that was remarkably increased in only NPKC (2.5%) according to annual long-term application. Thus we suggest that annual compost application with optimum NPK could make stable and sustainable rice production.
        431.
        2016.03 KCI 등재 서비스 종료(열람 제한)
        경부 고속철 40 m 단경간 PSC 교량을 대상으로 38 자유도 KTX 동력차를 주행속도 500 km/h까지 12 단계 불규칙 궤도형상과 상호 작용력을 고려하여 해석하였다. 차량의 윤축하중과 중심회전각을 평가하기 위하여 170 m 일반도상을 교량과 조합하여 횡압과 탈선계수 그리 고 윤중감소율을 허용기준과 비교하였다. 단순교와 연속교의 교량받침 최대 변위와 누적이동거리를 주행속도별로 해석하였다. PTFE 마찰판 과 DP-mate의 EN-1337-2 기준의 장기마찰시험을 수행하였다. 수행된 장기마찰시험은 차세대 고속철의 증가되는 주행속도를 고려하여 개선 방안을 제안하였다.
        432.
        2016.02 KCI 등재 서비스 종료(열람 제한)
        The government has conducted a plan of total maximum daily loads(TMDL), which divides with unit watershed, for management of stable water quality target by setting the permitted total amount of the pollutant. In this study, BOD concentration trends over the last 10 years from 2005 to 2014 were analyzed in the Geumho river. Improvement effect of water quality throughout the implementation period of TMDL was evaluated using the seasonal Mann-Kendall test and a LOWESS(locally weighted scatter plot smoother) smooth. As a study result of the seasonal Mann-Kendall test and the LOWESS smooth, BOD concentration in the Geumho river appeared to have been reduced or held at a constant. As a result of quantitatively analysis for BOD concentration with exploratory data analysis(EDA), the mean and the median of BOD concentration appeared in the order of GH8 〉GH7 〉GH6 〉GH5 〉GH4 〉GH3 〉GH2 〉GH1. The monthly average concentration of BOD appeared in the order of Apr 〉Mar 〉Feb 〉May 〉Jun 〉Jul 〉Jan 〉Aug 〉Sep 〉Dec 〉Nov 〉Oct. As a result of the outlier, its value was the most frequent in February, which is estimated 1.5 times more than July, and was smallest frequent in July. The outlier in terms of water quality management is necessary in order to establish a management plan for the contaminants in watershed.
        433.
        2016.01 KCI 등재 서비스 종료(열람 제한)
        Long-term variations of PM10 and the characteristics of local meteorology related to its concentration changes were analyzed at 4 air quality sites (Ido-dong, Yeon-dong, Donghong-dong, and Gosan) in Jeju during two different periods, such as PI (2001-2006) and PII (2007-2013), over a 13-year period. Overall, the long-term trend of PM10 was very slightly downward during the whole study period, while the high PM10 concentrations in PII were observed more frequently than those in PI. The concentration variations of PM10 during the study period was clarified in correlation between PM10 and meteorological variables, e.g. the low (high) PM10 concentration with large (small) precipitation or high (low) radiation and in part high PM10 concentrations (especially, Donghong-dong and Gosan) with strong wind speed and the westerly/northwesterly winds. This was likely to be caused by the transport effect (from the polluted regions of China) rather than the contribution of local emission sources. The PM10 concentrations in “Asian dust” and “Haze” weather types were higher, whereas those in “Precipitation”, “Fog”, and “Thunder and Lighting” weather types were lower. The contribution of long-range transport to the observed PM10 levels in the urban center (Ido-dong, Yeon-dong, and Donghong-dong), if estimated by comparison to the data of the background site (Gosan), was found to explain about 80% (on average) of its input.
        434.
        2015.10 KCI 등재 서비스 종료(열람 제한)
        미계측유역의 유출량 모의는 수문학 분야에서 필수적인 사항이다. 강우-유출 모형을 이용하여 신뢰성 있는 유출량을 모의하기 위한 핵심사항은 강우-유출 모형의 매개변수를 추정하는 것이다. 하지만 현재 우리나라는 불충분한 수문자료로 인해 매개변수 추정에 어려움이 존재한다. 본 연구의 목표는 불확실성 반영을 위한 Bayesian 통계기법 기반의 강우-유출 모형의 매개변수를 지역화 하는 것이다. 그 방법은 다음과 같다. 첫째, 본 연구는 세계적으로 널리 사용되고 있는 Sacramento 강우-유출 모형에 Bayesian Markov Chain Monte Carlo 기법을 연계한 Bayesian Sacramento 강우-유출 모형을 사용하여 계측유역을 대상으로 13개 매개변수를 최적화하고 각 매개변수의 사후분포를 도출하였다. 둘째, 매개변수와 유역특성인자 사이에 회귀특성을 얻기 위해 다중선형회귀분석을 적용하여 유역특성을 고려한 지역화 매개변수를 결정하였다. 다중회귀분석을 통하여 산정된 지역화 매개변수를 계측유역에 전이하여 유출량을 모의 후 통계적 효율기준인 N-S계수, 일치계수 및 상관계수를 사용하여 지역화 매개변수 검증을 수행하였다.
        435.
        2015.10 서비스 종료(열람 제한)
        고속철 PSC 교량받침의 장기 마찰시험은 EN1337-2와 CUAP03.01/78기준을 기반으로 동일한 수직압력에 대한 온도변수별 누적 마찰거리 25,000 m 장기마찰시험을 수행하였다. 기존의 PTFE판은 우수한 마찰계수 결과에도 불구하고 10,000 m에서 손상되어 한계 내구성능을 나타 내었고, 반면에 DP-Mate판은 일부 온도구간에서 한계 마찰계수를 상회하였으나 성공적으로 장 기마찰시험을 만족시켰다. 개발된 마찰시험장치를 이용하여 온도변화(-35℃~70℃)내 저속(0.4 mm/s)시험 12 Cycle과 상온 고속(15 mm/s)시험 11 Cycle 을 32 일간 수행하였다.
        439.
        2015.05 KCI 등재 서비스 종료(열람 제한)
        국내 4대강에 설치된 다기능보는 하천을 횡단하는 수공구조물로써 고정보와 가동보로 구분되어 설치되었으며, 각 다기능 보의 수문운영 방식에 따라 유량이 변화하여 하상변동 및 유사이동 형태의 변화 가능성이 있다. 본 연구에서는 다기능보의 수문운영에 따른 장기 하상변동을 금강유역을 중심으로 연구하였다. 연구결과, 금강에서는 다기능보의 설치 및 수문운영 시나리오에 따라서 최심하상고의 변화가 연평균하상고의 변화에 비해서 상대적으로 큰 것으로 나타났다. 최심하상고의 하상저하는 최대 2.79 m, 하상상승은 최대 1.90 m까지 발생하는 것으로 나타났으며, 연평균하상고의 하상저하는 최대 2.16 m, 하상상승은 최대 1.24 m까지 발생하는 것으로 나타났다. 또한 하상변동에 따른 홍수위 분석 결과, 다기능보 설치 후에 홍수위가 대부분 상승하는 것으로 나타났으며, 최대 2.23 m까지 상승하는 것으로 나타났다. 이러한 결과로 인해서 제방의 여유고를 상회하는 홍수위가 발생할 가능성이 있기 때문에, 하천의 유사관리 및 하천계획수립을 함에 있어서 다기능보의 수문운영을 고려해야 한다고 판단된다. 또한 본 연구결과는 향후 하천계획을 수립함에 있어서 종단적 하도관리 및 안정하상 채택 등을 위해서 기초자료로 활용될 수 있을 것으로 본다.