• Journal of Periodontal and Implant Science
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• v.23 no.3
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• pp.635-645
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• 1993

This study was perfomed to investigate the prosthodontic and periodontal status of the abutment teeth in distally extending bridges(DEBs) (78 cases) and removable partial dentures(RPDs) (43 cases) for 122 patients (55 males and 57 females) visiting department of Periodontology, Seoul National University Hospital. The average wearing periods were 67.8 months for DEBs and 66.4 months for RPDs. 38.4% of the patients in DEBs and 35.9% in RPDs complainted of chewing discomfort and 22.6% and 24.4% were not chewing on the prosthodontically - treated sides, respectively. In DEBs, when the restoration for 2nd molar supported by 1st molar & 2nd premolar was grouped to type 1, 1st molar supported by 1st & 2nd premolars was type 2, and 1st & 2nd molars supported by 1st & 2nd premolars was type 3, there was a significant differences only in the tooth mobility score among clinical parameters (type 2>type 1>type 3). In RPDs, when bilateral free-end case was grouped to type 1, and unilateral case was type 2, there was a significant difference in the Gingival index (type 1>type 2). In DEBs, 62.8% of restoration were overcontoured, 72% had interproximal space closures, 30.5% overextended pontics and 86.6% overhanging margins. In RPDs, 24.4% of the restorations were overcontoured, 45.5% had interproxinal space closures and 58.3% overhanging margins. From these results of this study, periodontal problems caused by prosthodontic defects were considered to be contributing factors in chewing discomfort.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2016.10a
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• pp.241-242
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• 2016

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2016.10a
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• pp.257-258
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• 2016

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.12 no.2
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• pp.107-119
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• 2014

The worldwide Status-of-Art survey for the in-situ experiments of the engineered barrier system for HLW underground disposal was performed as a preliminary action for the design of the in-situ demonstration at KURT. Some nations, which have executed or is ongoing the in-situ experiments at their underground research facilities, were summarized in this review. The demonstration projects reviewed were TBT/Sweden-France, LOT/Sweden, HE-E/Switzerland, PRACLAY/Belgium, FEBEX/Spain, HORONOBE/Japan, and BCE/Canada. The investigated items for the projects were mainly their purposes, constitutional structures, test conditions, monitoring parameters and the measuring tools, and test results. In this review, the hardware design and the assembling of the test system were more concentrated rather than their experimental results, because the purpose of this review is to achieve the necessary information for the practical design of the in-situ experiment to be installed at KURT. A mid scale in-situ demonstration of EBS at KURT, that is called IN-DBES, will be launched right after the completion the expanding project of KURT in 2015. It is hoped that the structural design, installing methods, hardware equipments required in the establishment of IN-DEBS will be referred on this review.

• Korean Journal of Construction Engineering and Management
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• v.19 no.2
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• pp.96-106
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• 2018

The government adopted activation policy of real estate to overcome low economic growth rate. Real estate activation plan adopted by the government raised credit limit by lowering the regulation, and reduced real estate investment cost by reducing the base rate. Also, delayed transfer tax on multi-house owner to activate real estate investment and resolved purchase right resale. Relief of real estate regulate caused increase of housing sales and price increase, and the real estate market changed to overheating aspect such as premium upon completion of lot sale in a short time. Such market atmosphere greatly increased household debs as owners own houses based on 'financial debt' instead of their income. Since 2017, real estate policy was reinforced to reduce household debts and lending rate was raised due to rise of base rate, accordingly, burden of household debt is expected to increase. This research suggested a plan for the Financial Supervisory Service to efficiently manage the financial world by analyzing the cause and problem of household debs.

• Computers and Concrete
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• v.16 no.1
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• pp.163-178
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• 2015

Due to the increase of the use of precast concrete structures in multistory buildings, this paper deals with the behavior of an specific type of beam-column connection used in this structural system. The connection is composed by concrete corbels, dowels and continuity bars passing through the column. The study was developed based on the experimental and numerical results. In the experimental analysis a full scale specimen was tested and for numerical study, a 3D computational model was created using a finite element analyze (FEA) software, called DIANA. The comparison of the results showed a satisfactory correlation between loading versus displacement curves.

• Steel and Composite Structures
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• v.28 no.4
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• pp.449-460
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• 2018

This paper reports the experimental results of three through bolt beam-column connections under pure shear forces using modified push-out tests. The investigated specimens include extended end-plates and six through-bolts connecting square concrete-filled steel tubular column (S-CFST) to steel beams. The main goal of this study is to investigate if and how the mechanical shear connectors, such as steel angles and stud bolts, contribute to the shear transfer mechanisms in the steel-concrete interface of the composite column. The contribution of shear studs and steel angles to improve the shear resistance of steel-concrete interface in through-bolt connections was investigated using tests. The results showed that their contribution is not significant when the beam-column connection is included in the push-out tests. The specimens failed by pure shear of the long bolts, and the ultimate load can be predicted using the shear resistance of the bolts under shear forces. The predicted values of load allowed obtaining a good agreement with the tests results.

• Steel and Composite Structures
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• v.7 no.5
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• pp.377-390
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• 2007

In the design of concrete filled composite columns, it is assumed that the load transfer between the steel tube and concrete core has to be achieved by the natural bond. However, it is important to investigate the mechanisms of shear transfer due to the possibility of steel-concrete interface separation. This paper deals with the contribution of headed stud bolt shear connectors and angles to improve the shear resistance of the steel-concrete interface using push-out tests. In order to determine the influence of the shear connectors, altogether three specimens of concrete filled composite column were tested: one without mechanical shear connectors, one with four stud bolt shear connectors and one with four angles. The experimental results showed the mechanisms of shear transfer and also the contribution of the angles and stud bolts to the shear resistance and the force transfer capacity.

• Steel and Composite Structures
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• v.4 no.4
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• pp.303-315
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• 2004

Frame composed of concrete-filled steel tubular columns and I-shaped steel beam has been researched in order to development reasonable connection details. The present paper describes the results of an experimental program in four different connection details. The connection details considered include through-bolt between I-shaped steel beams and concrete-filled steel tubular columns and two details of welded connections. One of the welded connection details is stiffened by angles welded in the interior of the profile wall at the beam flange level. The specimens were tested in a cruciform loading arrangement with variable monotonic loading on the beams and constant compressive load on the column. For through-bolt details, the contribution of friction and bearing were investigated by embedding some of the bolts in the concrete. The results of the tests show that through-bolt connection details are very ductility and the bearing is not important to the behavior of these moment connections. The angles welded in the interior of the profile wall increase the strength and stiffness of the welded connection detail. In addition, the behavior curves of these connections are compared and some interesting conclusions are drawn. The results are summarized for the strength and stiffness of each connection.

• Steel and Composite Structures
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• v.23 no.3
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• pp.351-362
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• 2017

This paper presents an experimental study on the behavior of composite floor slab comprised by a new steel sheet and concrete slab. The strength of composite slabs depends mainly on the strength of the connection between the steel sheet and concrete, which is denoted by longitudinal shear strength. The composite slabs have three main failures modes, failure by bending, vertical shear failure and longitudinal shear failure. These modes are based on the load versus deflection curves that are obtained in bending tests. The longitudinal shear failure is brittle due to the mechanical connection was not capable of transferring the shear force until the failure by bending occurs. The vertical shear failure is observed in slabs with short span, large heights and high concentrated loads subjected near the supports. In order to analyze the behavior of the composite slab with a new steel sheet, six bending tests were undertaken aiming to provide information on their longitudinal shear strength, and to assess the failure mechanisms of the proposed connections. Two groups of slabs were tested, one with 3000 mm in length and other with 1500 mm in length. The tested composite slabs showed satisfactory composite behavior and longitudinal shear resistance, as good as well, the analysis confirmed that the developed sheet is suitable for use in composite structures without damage to the global behavior.