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        검색결과 6,731

        6564.
        2000.03 KCI 등재 서비스 종료(열람 제한)
        In the country where the population concentrates in the metropolis with the narrow land, development of the ocean space is necessary. Recently, mega-float offshore structure has been studied as one of the effective utilization of the ocean space. And very large floating structures are now being considered for various applications such as floating airports, offshore cities and so on. This very large structure is relatively flexible compared with real floating structures like large ships. when we estimate dynamic responses of these structures in waves, the elastic deformation is important, because vertical dimension is small compared with horizontal. And it is necessary to examine the effect of ocean wave external force received from the natural environment. In this study, the mat-type large floating structure is made to be analytical model. And the analysis of the dynamic response as it receives regular wave is studied. The finite element method is used in the analysis of structural section of this model. And the analysis is carried out using the boundary element method in the fluid division. The validity of analysis method is verified in comparison with the experimental result in the Japan Ministry of Transport Ship Research Institution. In order to know the characteristics of the dynamic response of the large floating structures, effects of wavelength, bending rigidity of the structure, water depth, and wave direction on dynamic response of the floating structure are studied by use of numerical calculation.
        6565.
        2000.03 KCI 등재 서비스 종료(열람 제한)
        Recently, in the shipping companies have been employing prudently in order to prevent from sea accidents occurred by human factors. Also the students of merchant marine universities are choosing prudently the shipping companies when taking a job. But many qualitative and quantitative factors are considered in decision making for the employment and the choice of a company. FSM(Fuzzy Structural Modeling) has been widely used in modeling the system composed of such qualitative and quantitative factor. In this paper, a case study is discussed for the analysis of the consciousness of the employment of shining companies and students' choice of such company in maritime university using FSM. Also this paper proposed the planes for educating and recruitment guiding the student in maritime university.
        6566.
        2000.03 서비스 종료(열람 제한)
        This study is a suggest a measurement method of lateral displacement, which can be used to judge the stability of bridge abutment on soil undergoing lateral movement. The abutment of bridge on soft foundation makes lateral movement due to the settlement of back fill and lateral flow. To measure the displacement of such a abutment, there are a lot of indirect method for measurement such as survey of leveling or inclinometer gauge around the abutment. But all of them are not sufficient to confirm the ground behavior and measure the exact lateral behavior of structure. As making the structure and pile cooperatively by measuring the movement of lateral displacement, for measuring the abutment displacement precisely by using the inclinometer. In this work, we try to suggest efficient measuring method of abutment displacement and its application.
        6567.
        2000.03 서비스 종료(열람 제한)
        This stability of a plate structure is very crucial problem which results in wrinkle and buckling. In this study, the effect of the pattern of spot-welding points of the two rectangular plates on the compressive and shear buckling load is studied with respect to the thickness, aspect ratio of plates and number of welding spots. Buckling coefficient of the plate not welded was compared with that of two plates with various thickness to extract the effect of thickness. The effect of number of welding spots are studied in two directions, longitudinal and transverse directions. The conclusions obtained were that the reinforcement effect was maximized when the aspect ratio was close to 1.75 at compressive load condition and that the effect of number of welding spots in transverse direction was larger than that in longitudinal direction at shearing load condition.
        6568.
        2000.03 서비스 종료(열람 제한)
        The planning process of complex projects in oceanic architectural engineering is characterized by the cooperation of many involved specialists and by a high degree of information exchange. In order to improve the quality of the structural design of oceanic buildings, information of different involved partners in the planning process has to be integrated. This paper aims to introduce a concept of the integrated structural design for the floating-type oceanic building using STEP(Standard for the Exchange of Product Model Data). STEP(ISO 10303) is an international standard for the computer-interpretable representation and exchange of product data and it provides a consistent data exchange format and application interfaces between different application systems. In this paper, the structural design process and information of oceanic buildings is analyzed and product models are preposed fir the exchange of the structural design information between superstructure and floating structure. The entities for calculating wind loads, metacenter and restoring forces are represented by Express. As a case study a floating hotel is applicated to describe the STEP physical file.
        6569.
        2000.03 서비스 종료(열람 제한)
        For composing the structure model of national maritime power system by system structural modeling, in this study, the 50 basic factors are selected by survey of the extensive and through literatures on maritime, sea, maritime power and sea power. And the basic factors are classified into 36 component factors by cluster method. The 9 attributes are extracted by the application of the principle component analysis method, one of the factor analysis method in system engineering, to component factors. In this study, we define the attributes composing the national maritime power system by integrating the result of this study and existed our studies relating to this topic. Which are showed in Table 2. and we show the structure model of national maritime power system in Fig. 3. In Table 2, the 9 attributes are as follows : the fundamental power of maritime, shipping and port power, naval power, fishing power, shipbuilding power, the power of ocean research and development, dependency on seaborne trade, the protection power of ocean environment and the will and inclination of govemment. Also, in the case of evaluating this system, we conform the importance of considering the interactions among the attributes which have strong interactions in structure model of national maritime power system.
        6570.
        2000.03 KCI 등재 서비스 종료(열람 제한)
        한국산 쓴풀속(용담과) 식물 중 남한에 분포하는 5분류군과 변이체라 생각되는 1분류군, 총 6분류군에 대하여 줄기, 잎, 자방, 악, 자방의 횡단면, 주두, 잎표피, 주맥표면, 화관열편 표면, 밀선, 종피와 화분의 해부학적 형질과 미세구조를 조사하여 절과 종간의 한계를 분명히 하여 종 동정의 어려움을 해결하고 분류학적 위치를 설정하고자 본 연구를 수행하였다. 또한 북한에 분포하는 1분류군은 동경대학의 소장품을 관찰하여 분류군의 기재에 사용하였다. 연구결과, 자방의 내부구조, 밀선의 형태, 화관열편 표면의 미세구조 그리고 화분 표면의 무의 등에 의해 2개의 절로 구분되었고 밀선과 종피의 미세구조에 의해 종간의 구분이 가능하였으며, 이 형질들은 쓴풀속의 분류군들을 구별할 수 있는 매우 유용한 형질로 밝혀졌다. 변이체라고 생각되었던 큰잎쓴풀(화관 열편에 자색 점무늬를 갖는 분류군)A형은 자색 점 이외의 형질들에서는 전혀 차이를 찾아볼 수 없어 모종의 변이 폭에 넣는 것이 타당하다고 생각된다.
        6574.
        1999.12 서비스 종료(열람 제한)
        In the biological immunity, the immune system of organisms regulates the antibody and T-cells to protect the attack from the foreign materials which are virus, germ cell, and other antigens, and supports their stable state. It has similar characteristics that has the adaptation and robustness to overcome disturbances and to control the plant of engineering application. In this paper, we build a model of the T-cell regulated immune response mechanism. We have also designed an immune response controller(IRC) focusing on the T-cell regulated immune response of the biological immune system that include both a help part to control the response and a suppress part to adjust system stabilization effect. We show some computer simulation to control the vibration of building structure system with strong wind forces excitation also demonstrate the efficiency of the proposed controller for applying a practical system even with existing nonlinear terms.
        6575.
        1999.12 서비스 종료(열람 제한)
        In this thesis the legal systems related to real estate and sea area utilization are studied in order to improve them for construction of Very Large Floating Structure. Main research subjects are as follows: 1) Whether can Very Large Floating Structure be accepted or not as real estate like house and land\ulcorner 2) How can the sea area which is occupied by Very Large Floating Structure be utilized\ulcorner As the conclusion, the Very Large Floating Structure can be registered as real estate even though it is not specified by Korean law for the present. The design concept of Very Large Floating Structure can be interpreted as satisfying enough necessary conditions and factors for Very Large Floating Structure to become real estate. In the near future, we have to make improvement on the laws related with the construction of Very Large Floating Structures so that private sectors can joint the construction. In additions, a new law for various floating structures should be made as soon as possible.
        6576.
        1999.12 KCI 등재 서비스 종료(열람 제한)
        예로부터 식품으로 사용되어온 산돌배나무 (Pyrus ussuriensis) 열매를 대상으로 항산화 활성 성분을 찾기 위하여 그 MeOH추출물의 EtOAc분획을 대상으로 column chromatography를 실시하여 1, 4-dibenzenediol, chlorogenic acid 및 quercitrin등 세종의 화합물을 분리하고 DPPH free radical소거법을 이용하여 항산화활성을 측정하였다. 이중 quercitrin은 a-tocopherol 및 BHA보다 낮은 활성 (RC50=20μg)을 보였으나 1, 4-dibenzenediol (RC50=0.4μg) 와 chlorogenic acid (RC50=4μg)는 강한 활성을 보였다.
        6577.
        1999.12 KCI 등재 서비스 종료(열람 제한)
        Spotted cordierite occurs as the result of intrusion of Wolaksan Granite of Cretaceous age in the northern part of the Ogcheon Metamorphic Belt, forming a contact metamorphic zoning in accordance with the distance from the granite body: a cordierite-muscovite-biotite-quartz assemblage and the higher-temperature cordierite-biotite-quartz-(cummingtonite). These quartz-ubiquitous mineral assemblages identified in the cordierite spot seem to reflect Al-deficient condition of the protolith. TEM observations of textural relations between the cordierite and mica within the cordierite spot clearly reflect that cordierite was formed at the expense of micaceous matrix. A structure refinement of the poikiloblastic cordierite was performed by the Rietveld refinement method. Unit cell of the cordierite was determined to be as follows : lower-temperature type: a=17.1480(9)a, b=9.7743(6)a, c=9.3184(5)a, V=1561.9(4)a3, higher-temperature type: a=17.136(2)a, b=9.751(1)a, c=9.322(1)a, V=1557.7(4)a3. They show a remarkable difference in the unit cell dimension. The refinement results indicate that structural sites of lower-temperature cordierite are wholly occupied by appropriating ions. Compared to this, tetrahedral sites of the higher-temperature type exhibit an order/disorder ranging about 5-8% as the result of substitution between Si4+ and Al3+, except for T26 site occupied wholly by Al3+. These structural differences seem to be related to the formation temperatures of both cordierite types.
        6578.
        1999.10 KCI 등재 서비스 종료(열람 제한)
        The purpose of this study was to identify the controlling factors to construct tidal flat ecosystems having similar characteristics as natural ones. We transplanted the soil in a constructed tidal flat to a natural one and vice versa. Parameters monitored after these transplantations were silt content, organic matter, bacterial population and oxidation-reduction potential. Moreover, the relationship among silt content, organic matter and bacterial population was investigated by laboratory column experiment. The silt content, organic matter, bacterial population and vertical profile of oxidation-reduction potential in the soil transplanted from the constructed tidal flat to the natural one changed to similar values to those in the natural one. On the contrary, all the parameters for the soil transplanted from the natural tidal flat to the constructed one changed to similar values as those in the constructed one. The silt contents in these two transplanted soils were in proportion to the organic carbon contents and bacterial population. Similarly, the bacterial population in laboratory column experiment increased with the increase in silt and organic matter contents. It seemed to be important to select a place to enhance accumulative of silt and/or to maintain the silt content by hydrodynamic control of seawater in order to construct a tidal flat having similar characteristics as natural one.