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        검색결과 9

        1.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Pinus densiflora is a fixed-growth coniferous species that elongates its shoot once a year and finishes growing in early summer. However, it may produce additional shoots in the same year in response to external stimuli, called abnormal shoot growth. This study investigated the effects of open-field summer warming and drought on the abnormal shoot growth of P. densiflora seedlings. In March 2022, two factorial combinations were constructed, including two temperature treatments (control and 4°C increase) and two precipitation treatments (control and drought), with five replicates for each combination. The temperature treatment was performed for 87 days from May 14 to August 8, 2022, and the precipitation treatment was performed for 33 days from May 14 to June 15, blocking 100% of the ambient rainfall. The abnormal shoot occurrence rate and leaf unfolding stages were measured in November, and the shoot and root collar diameter growth rates were calculated by comparing the seedling height and root collar diameter measured in August (after the cessation of treatment) and October (after the end of growing period) with the initial values (i.e., May 2022). The abnormal shoot occurrence rate significantly increased under the warming treatment, showing a 410.6% increase in the warming plots (38.4%) compared to the control plots (7.5%). There was no significant difference in the shoot and root collar diameter growth rate regarding warming and drought treatments. Abnormal shoots may have been affected by high temperatures by inducing early transition to the next ontogenetic stage.
        4,000원
        2.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Mangroves are distributed in intertidal zones of coastal environments or estuarine margins, playing a critical role in the global carbon cycle. However, understanding of the carbon cycle role of mangrove associates in the Republic of Korea is still limited. This research measured soil respiration and leaf gas exchange in three habitats of Hibiscus hamabo (Gimnyeong, Seongsan, and Wimi) and analyzed the impacts on sites and months. Soil respiration was measured once a month from June to October 2022 and leaf gas exchange was measured monthly from June to September 2022. Soil respiration in August (5.7±0.8 μmol CO2 m-2 s-1) was significantly higher than that in other months (p<0.001) and soil respiration increased as air temperature increased (p<0.001). In Seongsan, net photosynthesis in July (9.0±0.9 μmol m-2 s-1) was significantly higher than that in other months (p<0.001). Net photosynthesis increased as stomatal conductance and transpiration rate increased during the entire period (p<0.001). Furthermore, a weak positive linear relationship was observed between soil respiration and net photosynthesis (r2=0.12; p<0.01). The results indicated that soil respiration was influenced not only by air temperature and season but also by net photosynthesis. This study is expected to provide basic information on the carbon dynamics of mangrove associates.
        4,000원
        3.
        2008.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        대공간 구조는 형태저항구조로서, 기둥-보로 구성되는 일반적인 건축골조구조가 설계외력에 대해 휨 및 전단으로 저항되는 것에 반해, 구조물의 내부에 기둥이 없는 공간을 내포하는 대공간 구조는 축력 및 면내 단면력에 의해 저항되는 경우가 대부분이다. 이러한 특성상 공간구조에는 일반적으로 장스팬이 사용되는 경우가 많으며, 그 결과 일반적인 골조와는 달리, 부재에 발생하는 변형도가 작은 경우에도 큰 변형이 발생하는, 즉 대변형 혹은 유한변형을 동반하게 된다. 일반적으로 수치해석에 있어 비선형 해석이란 기하학적 비선형 및 재료적 비선형, 또는 이 두 가지를 동시에 고려한 복합 비선형 해석을 들 수가 있다. 본 논문에서는 유한요소법으로 기하학적 비선형을 고려한 비선형 평형방정식을 적용하고, 부재의 응력-변형률 관계를 이용하여 재료적 비선형성도 함께 고려하였다. 사용된 수치해석 기법은 불안정 경로의 해를 찾아갈 수 있는 호장법을 적용하여 하중-변위 곡선을 추적하였다. 또한, 해석 결과는 범용 유한요소 프로그램인 ABAQUS를 이용하여 비교 검토하였다. 본 연구의 수치 해석결과 제시한 평면 및 공간 트러스의 비탄성 비선형 거동을 정확하고 효율적으로 예측 가능한 것으로 나타났다.
        4,300원
        4.
        2008.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        대공간 구조물은 3차원적인 힘의 흐름과 면내력에 의해 외부하중에 대한 저항 능력을 극대화 시킨 형태 저항 구조로서, 일반적인 골조와는 달리 부재에 대한 유한 변형을 동반 하므로 정적, 동적 해석에 관계없이 비선형 해석이 요구 된다. 대공간 구조물의 정확한 구조 해석을 수행하기 위해서는 기하학적 비선형 및 재료적 비선형 뿐 아니라 두 효과를 함께 고려한 비선형 해석이 필요하다. 기하학적 비선형 문제가 구조재료의 특성 및 위치에 따른 비선형을 고려하지 못하고, 구조재료의 비선형 문제가 기하학적 형상에 따른 비선형을 고려하지 못한다는 상호간의 단점을 해결하기 위하여, 본 논문에서는 유한요소법으로 기하학적 비선형을 고려한 비선형 평형방정식을 적용하고, 부재의 응력-변형률 관계를 이용하여 재료적 비선형성도 함께 고려하였다. 사용된 수치해석 기법은 불안정 경로의 해를 찾아갈 수 있는 호장법을 적용하여 하중-변위 곡선을 추적하였다. 본 연구의 수치 해석결과 제시한 평면 트러스의 비탄성 비선형 거동을 정확하고 효율적으로 예측 가능한 것으로 나타났다.
        4,000원
        7.
        1990.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This research was carried out as a basic survey to provide more effective and improved food service for the soliders of the Armed Forces who are serving to defend the Republic of Korea subjects were selected randomly who were serving in the army for a short-term. Following is the result of a survey regarding the situation of their meals, dietary life, and their food preference of 190 kinds of foodstuffs. As a result of surveying the dietary life of the soldiers, they indicated that there was dissatisfaction in the current Food Service because it lacked tasted and the same kind of meals were being served too frequently with regard to this, many subjects expressed that they were eating out because of the quality of they get from the regular meal service the meals, that is they were eating in restaurants to resolve their dissatisfaction over the quality of the meals. It was also surveyed that in the current meals there is a need to diversify ways in preparing food, increase the number of dishes, and improve the tasts of the food by using improved cooking method. It seemed that the soldiers were satisfied in the quantitative level of the current food service but that there is a need to improve the meals in quality. Following is the result of a survey on the preference of foodstuffs. In case of rice as the stationary food, mixture of five-grain plain white cooked rice showed a higher propensity compared to plain whte boiled rice. This shows that soliders prefer various cereals in their rice. Soliders liked soup made from meat better than vegetable soup or soup made from fish. Especially there was a high performance for beef soup. Soliders liked One-dish meals such as fried rice or boiled rice with asserted mixtures, noodled, and dumplings on the whole-soliders generally liked vegetables and they liked uncooked vegetables better than cooked vegetables. Generally everyone liked beverages and there was a high preference for dessert. Among various rice cakes soliders liked songpyon(rice cake steamed on a layer of pine needles) and injolmi (cake made from glutinous rice). On the other hand, soliders did not like food prepared with fish, biscuits and candy very much. In the way of preparing food, soliders liked food that were fried in deep far rather than food cooked in water. Also they liked pot stem better than soup. As examined in the survey, those surveyed wanted improvement in the quality and diversity of the food rather than increase the number of food and quality. Therefore there is a need for diversified supply and demand of quality of meal service.
        4,000원
        8.
        2005.02 KCI 등재 서비스 종료(열람 제한)
        The concentration of heavy metal were studied for the estimation of quality in herbal medicines which is Bupleuri Radix, Paeoniae Radix, Dioscoreae Rhizoma and Astragali Radix in products of north Gyeongbuk area. Also, we collected soils from several area in Gyeongbuk, and determined heavy metal concentration of soils by ICP. We compared with herbal medicines in products of Gyeongbuk and their soils. The average levels of heavy metal of herbal medicines in Gyeongbuk area are as follows : Mercury is 0.037㎎/㎏, Chromium is 0.093㎎/㎏, Nickel is 0.108㎎/㎏, Copper is 0.475㎎/㎏, Zinc is 3.14㎎/㎏, Manganese is 1.52㎎/㎏, Iron is 7.83㎎/㎏, and Cadmium, Lead and Arsenic is not detected. It was very lower in concentrations than those of average Korea area. For the heavy metals contents of Gyeongbuk area, in Gong Jung Ri, represented the higher level, it may be due to a near the road. The Cd contents in soil was not a wide difference. For the As and Pb contents in soil, Song Sa Ri (Bupleuri Radix) represented the higher level(0.68㎎/㎏, 1523㎎/kg). Correlation coefficients of heavy metal contents in cultured herbal medicines and their soils did not give reproducible results. But the degree of correlation between a few heavy metal contents of Dioscoreae Rhizoma and their soil showed the good transfer from the soil.
        9.
        1997.04 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        Peony is a medicinal herb which have utilized widely as chineses medicine. The paeoniflorin is the predominant component In peony root, monoterpene glucoside containing pinane structure. The effective components were extracted with the cold water from the intact peony roots, and effectively extracted with 70% ethanol from the dry powder of peony roots. The changes of paeoniflorin contents were investigated during the drying process of peony roots and processing of peony extract by the heat-treatment. Air-drying was the best condition for the preservation of paeoniflorin content among the drying processes of peony roots. But convective drying at 6 was recommended for the drying process of peony roots in large scale. The paeoniflorin in peony extracts was not destroyed by the treatment at 6 and 8 for 5 hrs, but destroyed 30%, 28% and 40% of paeoniflorin by treatment at 10 for 5 hrs, 115 and 121 for 10 minutes, respectively. The paeoniflorin was continueously extracted for 4 hrs from the dry pieces of peony roots(0.50.50.5cm) in boiling water but destroyed gradually after 4 hrs at 10. Paeoniflorins in 70% ethanol extracts of peony root were not destroyed at all in the process of concentration to dry powder at 60"C on vacuum.cuum.