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        검색결과 6,504

        5001.
        2017.01 KCI 등재 서비스 종료(열람 제한)
        The internal displacement of the corrugated steel plate structure reduces structural stability. In this study, we evaluated the stability of the corrugated steel plate culvert structure using an inspecting deformation rates between designs and measured 3D shapes. Also, a proper repair and reinforcement method will be proposed through analytical and experimental verification.
        5002.
        2017.01 KCI 등재 서비스 종료(열람 제한)
        reinforced concrete structures, carbonation phenomena associated with deterioration is important. So, this study conducted a visual inspection and a concrete durability test in Precise Safety Diagnosis, analyzed the result, and tried to suggest a reasonable repair method and range of concrete carbonation.
        5003.
        2017.01 KCI 등재 서비스 종료(열람 제한)
        When reinforcing an existing reinforced concrete beam-column building with a precast concrete panel, special connection between the PC member and the RC member is required to solve the time dependent deformation of the RC member and to receive the large shear forces. The aim of this study is to obtain the shear strength of upper connection between the existing RC beam-column and infilled PC wall panels in experimentally and theoretically. Thus, the static shear loading tests were conducted on the 6 specimens with the plate connection. Shear failure was resulted from the weakest portion of interior PC panel, exterior RC, and the connection, when the PC portion which located at the center of specimen was pulled upward from the bottom. The experimental result was compared with analytical result from ACI 318M-14 Chapter 17 for the shear strength of post-installed anchor and PCI Handbook 7th edition 6.8 Structural Steel Corbel (PCI Design Handbook 7th edition, 2010) for the strength of cast-in H-beam. The analytical and experimental results show final failure at the same location. The failure loading of experiment showed larger than average 6% to that of the analysis.
        5004.
        2017.01 KCI 등재 서비스 종료(열람 제한)
        This study presents the structural modelling method for the seismic behavior characteristics evaluation of flat stone bridge. To this end, we select the representative flat stone bridge according to the construction and configuration types. Also, this study provides the discrete element method for the reasonable seismic modelling of discontinuum structures.
        5005.
        2017.01 KCI 등재 서비스 종료(열람 제한)
        This paper addresses simplified method for nonlinear soil–structure interactions (SSI) analysis of base-isolated nuclear power plant (NPP) structure under incident seismic waves. The accuracy and applicability of the method are evaluated by comparing with nonlinear time history responses obtained by the boundary reaction method (BRM).
        5006.
        2017.01 KCI 등재 서비스 종료(열람 제한)
        This study proposed a seismic isolation system which uses the LM guide featuring high hardness and low frictional coefficient and a viscoelastic damper possessing high restitution force and damping force in order that existing seismic isolation systems using conventional sliding bearing way can be applied to a structure, and intended to analyze the proposed seismic isolation system's utilization possibility as a seismic isolation system for rescue through an experiment utilizing 6 earthquake waves being entered according to the reoccurrence cycle on the basis of performance-based design, and the case of Kyungju earthquake and to interpret the results of experiment.
        5007.
        2017.01 KCI 등재 서비스 종료(열람 제한)
        This study evaluates seismic risk of steel ordinary concentrically braced frames. Based on the risk integral concept, the collapse probabilities in 50 years are calculated for the 3-, 5- and 10-story braced frames. The evaluation results present that the collapse probabilities in 50 years are increased for the higher braced frames although they are identically designed according to the current domestic seismic design code.
        5008.
        2017.01 KCI 등재 서비스 종료(열람 제한)
        최근에 도시화와 산업화 및 교통망의 지속적인 확보로 인하여 발파공사를 시행하는 공사장이 증가하고 있다. 발파공사는 주변 주 민들의 주거환경과 인접시설물들의 안전에 큰 영향을 미치므로 이에 대한 대책이 필요하다. 본 연구에서는 발파피해를 줄이기 위한 방법 중에 서 발파공내의 발파메커니즘을 규명하고 개선하였다. 일반적인 공법에서 발생하는 천공경과 폭약경 사이의 차이로 인한 공간에서 디커플링효 과를 규명하고, 이 공간의 매질을 변화시킴으로서 발파 시 진동발생의 규모를 규명하였다. 발파시험은 도로, 철도, 산업단지에서 실시하고, 발 파진동을 측정하였다. 측정된 진동속도를 회귀분석하여 발파진동추정식을 산정하고 이를 이용하여 이격거리를 산정하였다. 공내 매질이 공 기보다는 물처럼 비중이 큰 경우에 충격력은 크나 폭발 지연시간이 짧아 진동전달거리가 작아 이격거리를 크게 확보할 수 있다. 핵심용어 :
        5009.
        2017.01 KCI 등재 서비스 종료(열람 제한)
        RC 무량판 구조는 강도 뿐만 아니라 사용성 조건에 지배받을 수 있으며, 시공 과정 및 이에 따른 동바리로 연결된 슬래브들 간의 중 력하중의 분포가 무량판의 장단기 거동에 영향을 주는 중요한 요소로 작용할 수 있다. 조기재령 슬래브에 과하중이 작용하여 균열이 발생하는 경우 시공 과정에서 무량판 구조의 처짐이 크게 증가할 수 있으므로, 동바리 재설치를 통해 다층지지 슬래브에서 하중의 수직 분포를 조절하는 것은 처짐을 감소시키는 데 도움이 될 수 있다. 이 연구에서는 무령판 구조의 장단기 처짐에 대한 동바리 재설치 작업의 영향을 분석한다. 다양 한 동바리 재설치 조건과 슬래브 설계 및 시공 조건에 따른 슬래브 시공하중이 간편법에 의하여 정의되고, 시공 과정과 콘크리트의 균열 및 장 기 효과를 고려한 슬래브 처짐 실용해석법을 통해 장단기 처짐이 산정된다. 변수연구를 통하여 동바리 재설치 작업의 슬래브 처짐 저감효과를 검증하며, 슬래브 처짐을 위한 동바리 시공과 슬래브 설계 및 시공에 대한 최적 조건을 분석한다.
        5010.
        2016.12 KCI 등재 서비스 종료(열람 제한)
        글로벌금융위기 이후 우리나라 해운산업은 기업퇴출, 자본잠식, 법정관리 등 다양한 형태로 불황을 맞고 있다. 경기변화에 민감하 고, 선박확보에 거대자본이 요구된다는 점을 감안할 때 자본구조의 최적화는 기업가치를 극대화할 수 있는 기초가 되고, 기업부실화를 극복할 수 있는 수단이 될 것이다. 이에 본 연구는 선행연구들을 바탕으로 10년 이상 적격 감사보고서를 제출한 국내 46개 해운기업을 대상으로 자본 구조와 기업특성 간 관계를 해운경기변화를 고려하여 규명해보고자 하였다. 실증결과, 국내 해운기업의 자본구조는 기업규모, 자산유형화정 도, 수익성, 비부채성세금효과 등과는 부(-)의 관계가, 성장성은 정(+)의 관계가 있음 실증되었다. 해운경기반영 모형별 진단에서는 상대적으 로 불황기모형은 전체기간 분석결과와 큰 차이를 보이지 않은 반면, 상대적 호황기모형에서는 유동성이 추가적으로 유의하였으며, 비부채성 세금효과와 성장성은 유의하지 않음을 확인할 수 있었다. 또한, 글로벌 상장해운기업을 대상으로 한 기존연구들과 연구결과에서 큰 차이는 없 었으나, 비부채성세금효과, 선박유형화정도, 성장성이 국내 해운기업에 추가적으로 유의함을 확인할 수 있었다. 하지만, 국내 해운기업의 자본 구조관련 연구를 보다 강화하기 위해서는 목표부채비율, 조정속도 등의 연구가 추가적으로 진행될 필요성은 있을 것이다.
        5011.
        2016.12 KCI 등재 서비스 종료(열람 제한)
        In recent years, the population structure has been changed by the progresses of 6th-industrialization and transportation in farming areas. This study aims to suggest a regional development plan of farming areas in accordance with the demographic changes. Population structure indicators were derived from previous studies and literature review in order to identify the types of farming areas. Demographic indicators separated to depopulation and population growth in farming areas through a standardized scoring method. This research found that the division of economy is not only the most important division in any other regional development divisions but also necessary to develop new sources of non-farm income through traditional culture, natural environment. In the social division, it is necessary to secure the facilities for the formation of a sense of community to multicultural families and existing residents in farming areas. In the environmental division, it is desirable to improve the quality and satisfaction of life for residents such as the sidewalk and park that utilize ecological environment, culture, history for both depopulation and population region. In the physical division, there is a need for improvement of the facilities of basic living infrastructure service such as roads, water supply and sewerage systems. In the institution division, sustainable financial support of the central government policy for farming areas is crucial for the improvement of residential environment in the farming areas of depopulation and population region.
        5012.
        2016.12 KCI 등재 서비스 종료(열람 제한)
        최근 납의 대체물질로서 연구되고 있는 바륨(Ba)과 요오도(I) 등은 차폐능은 우수하지만, 30 keV 근처의 에너지 영역에서 특성 X선이 방출되는 문제점이 있다. 본 연구에서는 황산바륨(BaSO4)과 산화비스무스(BiO)로 구성된 친환경 이중차폐체의 적용가능성을 검증하기 위한 선행연구로 몬테카를로 시뮬레이션을 통해 투과스펙트럼, 차폐율 등을 평가하였다. 평가결과, 0.6mm 두께의 Pb 단일층과 비교하여 0.1 mm 두께의 BaSO4 하부층에 BiO 층의 두께가 0.4 mm 와 0.5 mm에서는 각각 차폐율이 1.9 %, 3.9 % 높은 성능을 보였다. 뿐만 아니라, 상대적인 중량 또한 각각 34.5 %, 28 % 경량화가 가능하다는 것을 알 수 있었다.
        5015.
        2016.11 KCI 등재 서비스 종료(열람 제한)
        Purpose: Team cohesion and team work are the usual components for explanation of team performance in Korean sport psychological field which is somewhat limited. So for the purpose of systematic and effective explanation of performance, this study was aimed to investigate concept of integral interaction among team members. Methods: Subjects of study were 255 middle and high schools elite players(soccer, basketball and volleyball). Results were extracted from often-ended questionnaires. Data were inductively analyzed through a meeting of experts. Results: With regard to coach interaction, players of team sports represented assimilation, communication and role, and represented assimilation, communication and dependence in regard to colleague player interaction. Conclusion: The present study has contributed to existing literature by providing basic resources to further develop the questionnaires in relation to team sports interaction. Furthermore, the findings from this research may shed light on the scientific and objective knowledge in performance improvement of team sports.
        5016.
        2016.11 서비스 종료(열람 제한)
        Anaerobic digestion is one of the most economical ways to treat organic wastes; the production of excessive sludge is limited; aeration is not required; operation cost is low; valuable energy resource (methane) is produced. However, propionate, an intermediate substance during the process, is known to inhibit biochemical process at high concentration; but it is difficult to be degraded biologically as its oxidation is thermodynamically unfavorable (△G>0). However, there are several microorganisms which could oxidize propionate fully by their syntrophic association. Therefore, in this research, the propionate enrichment culture was produced in large amount (~1L), and the main players which are responsible for utilizing propionate are identified. Furthermore, the kinetic parameter was obtained from this research. Seed came from two different full-scale anaerobic digesters which is located in Joongrang (JR) and Sincheon (SC). 16s rRNA gnee based metagenomics results indicated that Smithella propionica and Methanobacterium beijingense were the most dominant species in all seeds. The fact that bacterial family Syntrophomonadaceae and archaeal genus Methanosaeta were also found significantly in all seeds means that there might be symbiotic relationship among propionate oxidizing bacteria, butyrate oxidizing bacteria, hydrogenotrophic methanogens and acetotrophic methanogens in complete oxidation of propionate. Based on the first order kinetic which indicated propionate degrading rate, k (1/day) on JR and SC was represented 0.0243 and 0.0223, respectively. Also, based on Modified-Gompertz model, umax on JR and SC was represented as 0.024 and 0.016, respectively.
        5017.
        2016.11 서비스 종료(열람 제한)
        Adsorption using highly porous and highly functionalized sorbents is a straightforward removal technology currently being employed, however the range of contaminants is limited. A novel sorbent was synthesized from activated carbon and Zr-based UiO66 metal organic framework to remove both cationic and oxyanionic metals from aqueous solutions. The composite was characterized using FSEM-EDS, FT-IR, XRD, and TGA, and showed successful integration of UiO66 on the surface of activated carbon. Batch adsorption tests with ICP-OES reveal that the composite has removal efficiency >95% for Pb (II), Cu (II), Se (IV), and As (V). The hybrid material is a promising sorbent for the removal of both cationic and oxyanionic metals for wastewater purification.
        5018.
        2016.11 서비스 종료(열람 제한)
        In order to cope with some drawbacks of conventional CCS (Carbon Capture and Storage) technologies, the new way to deal carbon dioxide have been studied a lot. One way to deal emitted carbon dioxide is to convert carbon dioxide into metal carbonate salt which can be used for various purposes such as raw materials for construction, additives for paper-making industries and so on. In this method, securing the source for metal cation is important and in this research, concentrated industrial wastewater was used to supply metal cation. In the wastewater, calcium and magnesium ions were dissolved and this could make cpatured carbon dioxide to be converted to metal carbonate salts. As a result of the chemical conversion, the amount of carbon dioxide converted to the precipitated salts and the crystal structures of them were suggested. To verify the crystal structures and the composition of salt mixtures, Scanning Electron Microscope and X-Ray Diffraction analysis were utilized.
        5019.
        2016.11 서비스 종료(열람 제한)
        최근 국가 온실가스 저감 목표인 BAU 대비 37%의 이행과 및 에너지원 다양화 측면에서 신재생에너지 보급활성화를 위한 다양한 정책이 발표되고 있으며, 이중 수송부문 신재생에너지연료의 보급 활성화를 위한 혼합의 무화제도(RFS)가 2015년 7월 31일부터 시행되었다. 본 제도의 유일한 이행 수단으로서 바이오디젤이 경유에 혼합의무화 되어 확대보급 될 전망이다. 하지만 대부분의 바이오디젤의 원료가 수입 팜유에 의존하고 있고, 유일한 국산원료인 폐식용유는 수거한계에 달한 상황이며, 바이오디젤 가격 또한 경유 가격에 비해 고가로 가격 경쟁력이 열악한 상황이다. 따라서 본 연구에서는 저가의 안정적 원료수급이 가능한 국내외 잠재원료에 대해 조사・선별하고 확보 가능량에 대해서 추정해 보았다. 또한 각 원료물질에 대한 유통구조 및 활용기술에 대해서도 조사하였다. 그 결과 국산 원료로서는 기존 폐식용유와 동물성유지 외에 식당폐유, 음식물 처리과정에서 추출된 유분 등이 추가로 조사 되었으며, 국외 원료로서는 팜유 추출 폐유인 팜 슬러지오일 등이 잠재 바이오디젤 원료로 선별 되었다. 또한 국내 유채유 및 미세조류 등도 중장기 원료로서 조사 하였다. 각 원료의 유통경로는 대부분 국산의 경유 기존 폐식용유와 동물성유지의 유통경로에 의존하고 있었고, 저급의 원료이다 보니 전처리 및 바이오디젤 전환기술개발이 필요한 실정이었다.
        5020.
        2016.10 서비스 종료(열람 제한)
        Background : Both Panax ginseng Meyer and Panax quinquefolius are obligate shade-loving plants whose natural habitats are broadleaved forests of Eastern Asia and North America. Panax species are easily damaged by photoinhibition when they are exposed to high temperatures or insufficient shade. In this study, a cytohistological study of the leaf structures of two of the most well-known Panax species was performed to better understand the physiological processes that limit photosynthesis. Leaves of ginseng plants grown in soil and hydroponic culture were sectioned for analysis. Methods and Results : Leaf structures of both Panax species were observed using a light microscope, scanning electron microscope, and transmission electron microscope. The mesostructure of both P. ginseng and P. quinquefolius frequently had one layer of noncylindrical palisade cells and three or four layers of spongy parenchymal cells. P. quinquefolius contained a similar number of stomata in the abaxial leaf surface but more tightly appressed enlarged grana stacks than P. ginseng. The adaxial surface of the epidermis in P. quinquefolius showed cuticle ridges with a pattern similar to that of P. ginseng. Conclusion : The anatomical leaf structure of both P. ginseng and P. quinquefolius shows that they are typical shade-loving sciophytes. Slight differences in chloroplast structure suggests that the two different species can be authenticated using transmission electron microscopy images, and light-resistant cultivar breeding can be performed via controlling photosynthesis efficiency.