In Korea, the occurrence frequency of earthquakes has recently increased, compared with the past. So, the various damages for cultural properties due to earthquake can be expected, and especially fortress structure is vulnerable to earthquake. Therefore, the resonable seismic characteristics evaluation is required to secure the safety for fortress structure with the various construction and configuration types. Also, we should consider the various applied load conditions as design variables. To this end, this study classifies fortress structures according to the construction and configuration types, and then applies the discrete element method to model and analyze fortress structures. Finally, the seismic characteristics is evaluated through slip condition due to the analysis results considering the various design variables.

PURPOSES: This study investigates the effect on concrete pavement accordance with the curing methods in cool weather and supports the best method in the field. METHODS: Two field tests evaluated the curing methods of concrete pavement in cool weather. Firstly, five curing methods were tested, including normal curing compound, black curing compound, bubble sheet, curing mat, and curing mat covered with vinyl. Concrete maturity was compared from temperature data. Secondly, normal curing compound and curing mat with vinyl, which showed the best performance, were compared in terms of maturity and join condition index. RESULTS: From the field tests, it is an evident that curing mat with vinyl accelerated the concrete strength. Therefore, it is possible to conduct saw-cut works in cool weather, which minimizes damage on concrete at joint. CONCLUSIONS: For concrete pavement in cool weather, using curing mat with vinyl as the curing method could overcome the strength delay. Therefore, strength and durability problems on concrete at joint due to cool weather would be fewer in the future.

PURPOSES : This paper focuses on strength development according to the mix design with cement type and mineral admixture from laboratory and field tests in cool weather. METHODS : Two methods evaluated the mix design of concrete pavement in cool weather. Firstly, laboratory tests including slump, air contents, setting time, strength, maturity, and freezing-thawing test were conducted. Three alternatives were selected based on the tests. Secondly, a field test was conducted and the optimum mix design in cool weather was suggested . RESULTS : It is an evident from the laboratory test that a mix with type Ⅲ cement showed better performance than the one with type Ⅰ cement. There was a delay in strength development of a mix with mineral admixture compared to mix design without any mineral admixture. In the field test, type Ⅲ cement+flyash 20% mix design proved the best performance. CONCLUSIONS : For concrete pavement in cool weather, mix design using type Ⅲ cement could overcome the strength delay due to mineral admixture. Moreover, it is possible to make sure of durability of pavement. Therefore, strength and durability problems due to cool weather would decrease.

As ZIF materials have their unique properties such as high surface area, tunable pore structure, thermal and chemical stability, they can be used in various applications including gas separation and catalysis. For synthesis of ZIF membranes, fixing sub-micron ZIF seed particles on the support is challenging and important. In this work, ZIF-8 seed layer was synthesized by conversion synthesis of ZnO layer on support in H-mIm solution, followed by the secondary growth synthesis of ZIF-8 membranes. The parameters of conversion seeding had been investigated to control the reaction rate combining the dissolution rate of ZnO and the crystallization rate of ZIF-8. This ZIF-8 membranes showed the better coverage of seeding layer and gas separation properties compared with the membranes prepared by traditional dip-coating seeding.

Various seismic isolation methods are being applied to bridges and buildings to improve their seismic performance. Most seismic isolation systems are the structural seismic isolation systems. In this study, the seismic performance of geotechnical seismic isolation system capable of isolating the lower foundation of the bridge structure from ground was evaluated. The geotechnical seismic isolation system was built with teflon, and the model structure was made by adopting the similitude law. The response acceleration for sinusoidal waves of various amplitudes and frequencies and seismic waves were analyzed by performing 1-G shaking table experiments. Fixed foundation, Sliding foundation, and Rocking foundation were evaluated. The results of this study indicated that the Teflon-type seismic foundation isolation system is effective in reducing the acceleration transmitted to the superstructure subject to large input ground motion. Response spectrum of the Rocking and Sliding foundation structures moves to the long period, while that of Fixed foundation moves to short period.

This study was conducted to investigate the effect of 1-methylcyclopropene(1-MCP), an inhibitor of ethylene action, on fruit quality and incidence of physiological disorders during simulated marketing period in early-season Asian pear(Pyrus pyrifolia Nakai) ‘Noksu’. Flesh firmness was decreased abruptly at 15 days after shelf-life in control fruits. which showed less than 10.7N, although those of 1-MCP-treated fruits were kept high value(>30.4N) during 20 days of shelf-life. ‘Noksu’ pears did not show any considerable differences in quality indices such as soluble solids content, titratable acidity during the shelf-life regardless of 1-MCP treatment. The reduction of ethylene production level by 1-MCP treatment did not appeared in ‘Noksu’ pear. Meanwhile, 1-MCP treated ‘Noksu’ pears showed significantly low respiration rate during shelf-life. Also, 1-MCP treatment blocked the incidence of physiological disorders including core browning, internal browning, water soaking and mealiness symptom during shelf-life. Consequently, we concluded that the 1-MCP treatment effectively inhibited the incidence of physiological disorders and extended the shelf-life for 10 days in early-season Asian pear ‘Noksu’.

Torsional constants of both rectangular cross section and circular cross section are induced by exact solution, and was easy to calculate since of simple shape. However, it is very difficult to calculate the torsional constant of both an arbitrary cross-section and a composite cross-section. In this study, a finite element formulation was proposed as a method to calculate the torsional constant of both an arbitrary cross-section and a composite cross-section. From the numerical study, numerical results was compared with exact solution.

In this study, finite element analysis of korean precast concrete panels was performed and 3D infinite element modeling was used. Infinite elements can be formulated in time domain and nonlinear behavior analysis is possible. Based on the numerical results, the performance of the packing layer of korean precast concrete panels was examined.

Numerical behavior of FRP(Fiber Reinforced Polymer) panel in steel frame structure was evaluated through the finite element analysis in this study. In order to numerical analysis, a experimental test results was used to develop a three dimensional finite element model of steel frame specimen. Numerical results of the steel frame specimen was well predicted the experimental behavior of steel frame specimen. Based on the developed three dimensional finite element model of steel frame specimen, the behavior of FRP panel in the steel frame specimen was evaluated. From the numerical analysis results, strength of the steel frame specimen with FRP panel was governed by FRP panel. Also, diagonal compression behavior governed the FRP panel in the steel frame specimen in the numerical analysis results.

Two steel-frame joint specimens with welding joint parts were constructed and evaluated. Two types of displacement load, monotonic and cyclic, were used to evaluate the steel-frame joint specimens. According to the experimental results, the maximum moment of the cyclic test results was 80% smaller than that of the monotonic test results. Local buckling was observed in the compression area of the H-beam flange. A finite element analysis model based on the experimental results was proposed to analyze the steel-frame joint specimens. The numerical results predicted the experimental behavior of the steel-frame joint specimens well. Therefore, it is possible to use the proposed finite element analysis model to evaluate middle- and low-rise steel-frame buildings constructed in South Korea.

In this study, a energy recovery ventilation system was applied to the pig model, intake and exhaust duct were installed at a height of top(2.1 m), middle(1.25 m) and bottom(0.4 m). In each of the 9 test sites, one test was performed from 10:00 to 18:00, optimal temperature exchange efficiency and temperature distribution were analyzed. In order to analyze the effect of the energy recovery ventilation system, the temperature of 31 points(4 points of the ventilation system and 27 points in the pig house model) was measured from 10:00 to 18:00. The test that showed the highest heat exchange efficiency was the configuration of middle intake duct and top exhaust duct, which was 75.44%. The test that showed the most uniform distribution was the configuration of middle intake duct and bottom exhaust duct. These results will be utilized to optimally design feeding environment of actual pig houses and to reduce fuel cost.

암석의 공극률을 산출하기 위해서는 일반적으로 한국암반공학회에서 정하고 있는 ‘암석의 공극률 및 밀도 측정 표준시험법’이 사용된다. 그러나 건조로를 이용하여 공극률을 구하는 이 같은 표준시험법은 8-24시간이 소요될 뿐만 아 니라, 실험 도중 4시간 간격마다 시료를 꺼내어 무게를 측정해야 하는 번거로움이 있다. 이와 같은 단점을 보완하기 위 해 본 연구에서는 마이크로웨이브 오븐을 이용하여 암석의 공극률을 측정하는 방법을 제안하였다. 마이크로웨이브 오븐 에 무게 모니터링 시스템을 구축하여 무게 측정의 오차 발생 요인과 실험 과정의 번거로움을 줄였다. 건조과정에서 시 료의 온도를 105±3°C 이내로 유지하기 위해 적절한 가열/휴지시간을 설정하였으며, 시료의 무게 변화량이 최초 무게의 0.1% 이내에 들면 모니터링을 중단할 수 있도록 알람 시스템도 구현하였다. 무게 모니터링 데이터에 곡선접합을 실시 하여 시료의 건조무게를 구하고, 이를 이용하여 공극률을 산출하였으며, 이렇게 구한 공극률을 표준시험법으로 구한 공 극률과 비교하였다. 사암을 이용해 실험한 결과, 마이크로웨이브 오븐으로 구한 공극률은 표준시험법으로 구한 공극률 과 최대 0.4%의 오차를 보여 표준시험법의 결과와 유사하였다. 또한 동일 시료를 이용하여 공극률을 반복 측정한 결과 , 표준편차가 최대 0.23% 정도로 정밀도 또한 양호하였다. 따라서 마이크로웨이브 오븐을 사용할 경우 높은 신뢰도로 공극률 산출이 가능할 것으로 판단된다.

본 연구는 서울시내 150개 음식점에서 수거한 계절별 음식 8종류 400건의 나트륨 및 칼륨 함량을 조사하였다. 계절별 음식은 여름철 메뉴 물냉면, 비빔냉면, 가을철 메뉴 떡볶이, 어묵꼬치, 튀김, 겨울철 메뉴 짬뽕, 우동, 해물 칼국수를 포함하였으며, 각 시료의 나트륨과 칼륨 평균함 량 분석결과는 통계적으로 유의한 차이가 있는 것으로 나타났다(p < 0.05). 나트륨 평균함량은 짬뽕 391.4 ± 72.7 mg / 100 g, 튀김 385.1 ± 92.7 mg / 100 g, 떡볶이 373.3 ± 90.6 mg / 100 g, 어묵 꼬치 366.9 ± 81.8 mg / 100 g는 다른 그룹에 비해 유의적으로 높게 나타났으며, 비빔냉면 255.3 ± 67.0 mg / 100 g, 해물칼국수 261.9 ± 57.2 mg / 100 g으로 가장 낮게 나타났다. 칼륨 평균함량은 짬뽕 88.6 ± 21.4 mg / 100 g, 비빔냉면 84.8 ± 24.1 mg / 100 g, 떡볶이 81.7 ± 23.7 mg / 100 g으로 다른 그룹에 비해 유의적으로 높게 나타났으며, 물냉면 41.2 ± 10.4 mg / 100 g, 어묵꼬치 39.5 ± 18.4 mg / 100 g, 우동 36.3 ± 17.8 mg / 100 g으로 가장 낮게 나타났다. 음식점에서 제공하는 각 메뉴의 1인분 기준으로 나트륨 함량은 짬뽕 3,780.7 ± 878.8 mg, 물냉면 3,463.2 ± 1178.7 mg, 어묵꼬치 2,715.9 ± 1078.3 mg, 해물칼국수 2,671.1 ± 786.5 mg, 우동 2,298.8 ± 592.3 mg으로 WHO에서 정한 1 일 권장 나트륨 섭취량 2,000 mg 보다 높은 결과를 보였다. 조리하는 음식점에 따라서 짬뽕은 많게는 5,768.9 mg 까지 나트륨이 함유되어 있어 나트륨 1일 권장 섭취량보 다 2.9배나 섭취하게 되므로 나트륨 과다 섭취로 인한 건강문제를 야기시킬 수 있다. 나트륨/칼륨 섭취비율에 대해 분석한 결과 어묵꼬치 10.8 ± 4.3, 우동 10.2 ± 4.0, 물냉면 8.6 ± 2.3, 튀김 5.9 ± 1.9 순으로 높게 나타났다. 비빔냉면이 3.2 ± 1.0으로 Na/K 섭취비율이 1에 가까운 비율을 나타냈고, 어묵꼬치의 Na/K 섭취비율이 최고 26.6로 칼륨함량에 비해 나트륨함량이 높은 것을 알 수 있었다. Na/K 섭취비율은 바람직한 섭취비 율인 1:1의 1/3이하로 칼륨 섭취가 크게 부족한 것을 알 수 있었다. 칼륨의 섭취량이 증가하면 나트륨 흡수를 감소시킬 수 있으므로 나트륨의 과잉 섭취로 유발되는 고혈 압에 대해 보호 작용을 한다고 알려져 있다. 나트륨 섭취 를 줄이기 위해서 정부의 시책과 더불어 국민건강을 위하여 나트륨 섭취를 줄이고 칼륨 섭취를 증가시킬 수 있는 효과적인 식단 및 나트륨을 비롯한 영양성분표시를 의무화해 소비자들에게 정확한 영양정보를 제공함으로써 올바른 식품의 선택뿐만 아니라 실천할 수 있는 생활습관의 교육 등 Na/K 섭취비율을 높일 수 있는 메뉴 및 방법을 다각적으로 연구할 필요가 있다.

The objectives of this study were to select the seeds of Cucurbitaceae and Solanaceae genotypes in terms of superior with bioactive compounds content and to inform sophisticated data for developing the high value-added products. We evaluated to aspects of the antioxidant activity, polyphenol content, and flavonoid contents in seeds from two vegetable family. We used in the Cucurbitaceae(watermelon, squash, bitter gourd, and sponge gourd) and Solanaceae(hot pepper, sweet pepper, and egg plant) the total 408 genotypes. In Cucurbitaceae, polyphenol content of watermelon and squash genotypes were ranged 19.9-343.8 and 6.1-81.2 mg·100 g-1 DW, respectively. The polyphenol content of watermelon genotypes was 12% among all genotypes over 160 mg·100 g-1 DW. The mean of flavonoid content in watermelon and squash genotypes represented 80 and 41.3 mg·100 g-1 DW, respectively. In Solanaceae, flavonoid content of hot pepper genotypes was ranged 64.4-472.5 mg·100 g-1 DW, with an average of 165.0 mg·100 g-1. The 23 hot pepper genotypes were classified over 90% antioxidant activity. The antioxidant activity of sweet pepper was ranged 35.9-90.3%, and 23% of all genotypes represented 82% antioxidant activity. The polyphenol and flavonoid content of egg plant was ranged 38.1-642.0 mg·100 g-1 DW and 14.2-1217.0 mg·100 g-1 DW, respectively. In addition, we selected that 8 egg plant with the superior genotypes for antioxidant activity, polyphenol, and flavonoid content. Results revealed that there was significant variation of antioxidant activity and bioactive compounds contents in both vegetable famaily. In addition, we suggested that selected genotypes seeds with high contain bioactive compounds will be more efficiency to develop natural value-added products.

The number of earthquakes is increased recently. A electrical equipment is very important in all electric system because it can make a serious problems in such as nuclear power plants like a black out. So, seismic safety design of electrical equipment is necessary to keep to use the convenience of electronics. In this study, threshold values of electronic equipment was founded out from the numerical results by using seismic load.

기관손상사고에 따른 수리작업 이후 동일한 원인으로 재발하는 경우에 대해 선박의 추진축계의수리 공정에 대해 고찰하였다. 그 결과 line boring machine 개선이 필요하며 Kit process 적용으로 엔진 수명 연장이 가능한 것으로 분석되었다.