• Journal of Korean Society of Steel Construction
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• v.18 no.5
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• pp.633-642
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• 2006

Serviceability design is required to control the cracking at the joint of precast decks with longitudinal prestress in continuous composite bridges. Details of twin-girder bridges are especially complex not only due to their main reinforcements and transverse prestresses for the design of long-span concrete slabs, but also due to the shear pockets for obtaining the composite action. This paper suggests the design guidelines for the magnitude of the effective prestress and for the selection of filling materials and their requirements that would allow for the use of precast decks for twin-girder continuous composite bridges. The necessary initial prestress was also evaluated through long-term behavior analysis. From the analysis, existing design examples were revised and their effectiveness was estimated. When a filling material with a bonding strength higher than the requirement is used in the region of a high negative moment, a uniform configuration of the longitudinal prestressing steels along thewhole span length of continuous composite bridges can be achieved, which would result in the simplification of the details and the reduction of the construction costs.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.4
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• pp.637-645
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• 2017

Jeju Island is composed of irregular volcanic rock layers formed by several volcanic activities. Since structure such as the offshore wind turbine has to support considerably large over turning moment due to long distance from foundation to load point and relatively large horizontal load. Pile foundations are needed to economically support such structure even in the case of rock layer. Therefore, in this study, mechanical performances are estimated by mixing ratio of water, cement, and sand to figure out optimal mixing ration of filling material for pile penetrated to rocky layers, and outcomes of this study are compared and analyzed with results of other researches. In the same conditions, mechanical performances of the mortar (S/(S+C)=20~40%) are better than those of cement paste and soil cement. On the basis of major outcome of this study, appropriate range of mixing and a strengthening model are suggested.

• Restorative Dentistry and Endodontics
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• v.39 no.1
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• pp.39-44
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• 2014

Objectives: The purpose of this study was to evaluate in vitro cytotoxicity of the pozzolan cement and other root-end filling materials using human periodontal ligament cell. Materials and Methods: Endocem (Maruchi), white ProRoot MTA (Dentsply), white Angelus MTA (Angelus), and Super EBA (Bosworth Co.) were tested after set completely in an incubator at $37^{\circ}C$ for 7 days, Endocem was tested in two ways: 1) immediately after mixing (fresh specimens) and 2) after setting completely like other experimental materials. The methods for assessment included light microscopic examination, cell counting and WST-1 assay on human periodontal ligament cell. Results: In the results of microscopic examination and cell counting, Super EBA showed significantly lower viable cell than any other groups (p < 0.05). As the results of WST-1 assay, compared with untreated control group, there was no significant cell viability of the Endocem group. However, the fresh mixed Endocem group had significantly less cell viability. The cells exposed to ProRoot MTA and Angelus MTA showed the highest viability, whereas the cells exposed to Super EBA displayed the lowest viability (p < 0.05). Conclusions: The cytotoxicity of the pozzolan cement (Endocem) was comparable with ProRoot MTA and Angelus MTA. Considering the difficult manipulation and long setting time of ProRoot MTA and Angelus MTA, Endocem can be used as the alternative of retrofilling material.

• Restorative Dentistry and Endodontics
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• v.17 no.1
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• pp.191-205
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• 1992

The purpose of this study was to evaluate the microleakage of class II composite resin inlays and compare them with the conventional light-cured resin filling restorations. Class II cavities were prepared in 60 extracted human molars with which cervical margins were located below 1.0mm at the cemento-enamel junction using No. 701 tapered fissure carbide bur. All of the prepared cavities were restored as follows and divided into 6 groups. Group I and 2 were restored using direct filling technique and group 3,4,5 and 6 were restored using direct inlay technique that was cemented with dual-cured resin cements. group I: Cavities were restored with light-curing composite resin, Brilliant Lux. group 2. Cavities were restored with light-curing composite resin, Clearfil PhotoPosterior. group 3: Cavities were restored with Clearfil CR Inlay and heat treated at $125^{\circ}C$ for 7 minutes. group 4: Cavities were restored with same material as group 3 and heat treated at $100^{\circ}C$ for 15 minutes. group 5: Cavities were restored with Brilliant (Indirect esthetic system) and heat treated at $125^{\circ}C$ for 7 minutes. group 6: Cavities were restored with same material as group 5 and heat treated at $100^{\circ}C$ for 15 minutes. All specimens were polished with same method and thermocycled between $6^{\circ}C$ and $60^{\circ}C$, then immersed in a bath of 2.0% aqueous solution of basic fuchsin dye for 24 hours. Dyed specimens were sectioned longitudinally and dye penetration degree was read on a scale of 0 to 4 by Tani and Buonocore's method 45). The results were as follows: 1. Microleakage was observed rather at the cervical margins than at the occlusal margins in all groups. 2. Composite resin inlay groups showed significantly less leakage than direct filling groups at the cervical margins (p < 0.001). 3. In composite resin inlay groups, there was no significant difference in microleakage between specimens by heat treating temperature and time (p > 0.05). 4. There was no significant difference in leakage between each groups at the occlusal margins (p > 0.05).

• Korea-Australia Rheology Journal
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• v.12 no.1
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• pp.55-67
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• 2000

In this paper, an experimental study of the rheological behavior of granular flow in a new type of storage silo is presented. The main characteristic of the new design is a hexagonal shape chosen with the objective of minimizing the stresses applied to the stored grains, and to reduce grain damage during the filling and emptying processes. Measurements of stress distribution and flow patterns are shown for a variety of granular materials. Because of the design of the silo, the granular material adopts its natural rest angle at all times eliminating collisional stresses and impacts between grains. A homogeneous, low friction flow is naturally achieved which provides a controlled stress distribution throughout the silo during filling and emptying. Secondary dynamic stresses, which are responsible for wall failure in conventional silos of the vertical type, are completely eliminated. A comparison between the two geometries is presented with data obtained for these silos and a number of granular materials. The discharge pattern inhibits powder formation in the silo and the filling system virtually eliminates unwanted material packing. Finally, notwithstanding the rheological advantages of this new design, the hexagonal cells that constitute the silo have many other advantages, such as the possible use of solar energy to control the humidity inside them. The cell type design allows for versatile storage capabilities and the elevation above the ground provides unlimited transportation facilities during emptying.

• Journal of the Korean Society of Industry Convergence
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• v.14 no.4
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• pp.151-156
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• 2011

The domestic mine development community the countermeasure establishment is insufficient about ground sinkage, not only the mine which is a in line is partial from the mine of the most which has become the rest mine and abandoned mine or the index sinkage occurs. The ground sinkage which occurs from the abandoned mine area most after operation is stopped, a long time passes and accurately predicts an occurrence location and a time with the residual sinkage which occurs, is difficult. Underground goaf of the abandoned mine and the closed shaft When considering the potentiality which causes the instability of ground, is a possibility of reaching a damage in the ground infrastructure or life. The underground shaft which is formed specially with mine development and goaf operates with the obstacle factor in the development project of the mine area, the ground sinkage which is caused by with sinkage, operates with the large safety accident occurrence factor where the important infrastructure of the railroad, road, residential area etc. is damaged. Therefore, In this paper, the goaf cave of the abandoned mine area, for the displacement behavior according to the filling factor of the material is to analyze the numerical analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.9
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• pp.3835-3840
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• 2012

Nanoimprint lithography (NIL) is an emerging technology enabling cost-effective and high-throughput nanofabrication. Recently a lot of research for the nanoimprint have been carried out, but almost are about merely experimental result relating to the material operation and the imprint fabrication, and numerical analysis relating to the understanding of the imprint process with R&D level. In this paper, the viscoelasticity analysis model is developed using the finite element method. With this model, the filling process and residual layer formation in nanoimprint are analyzed, which is evaluated by a nanoimprint experiment.

• Restorative Dentistry and Endodontics
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• v.21 no.2
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• pp.635-641
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• 1996

This study was designed to evaluate the anti cariogenic effect of F in primers, bonding agents, composite resins or glass ionomer cements in enamel. Twenty-five extracted teeth were selected and a cavity was prepared on either the buccal or the lingual surface of each tooth. After pumicing and etching, the samples were divided into 5 groups. In group A, the samples were primed, bonded and filled with ART bond and Brilliant Enamel (Coltene, Switzerland). Group B composed of Optibond and Herculited XRV (Kerr, USA), group C composed of Syntac and Tetric(Vivadent, Lichtenstein), and group D composed of Scotch-bond Multipurpose and Z 100 (3M, YSA). In group E, the samples were filled with glass ionomer cement (Fuji II LC, Japan), All surfaces except the 2mm beyond the cavosurface margin of the sample were protected, and samples were then put into an acid buffer for 3 days to develop the initial caries. The samples were then sectioned through the filling body into thin wafers and then examined with a polarizing microscope under water imbibition. The fluoride in primer, bonding agent, or composite filling material did not prevent the initial caries in the enamel area adjacent to the filling body whereas the fluoride in the glass ionomer did prevent the initial stage caries.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2006.11a
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• pp.370-373
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• 2006

Lastly, the problem of filling occurs in the process of concealed joint of adjacent components and was seen in joints between the structure and an electrical or mechanical device. Therefore, the dry processing which replaces wet joint was seen in joints between the structure and a door, ones between the structure and a finishing materials, ones between a gypsum board and electrical device, and ones between a water pipe and a tile finishing. And a process of separating the area of jointed parts in order to eliminate the problem of overlap was seen in joints between a door and a finishing material and ones between a gypsum board on the ceiling and a light. Lastly, an analysis of a process of exposing concealed parts indicated that the problem of filling could be applied to joints between the structure and an electrical or mechanical device and ones between a finishing material and a mechanical device. This study sought out methods to apply Environment Friendly Multi Housing Remodeling that allow easy remodeling as part of environment- preserving policies. It also contains basic data useful to implement long-life houses in the future by presenting a comprehensive design standard for them

• Restorative Dentistry and Endodontics
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• v.36 no.6
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• pp.510-514
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• 2011

Mineral trioxide aggregate (MTA), which was originally developed for repair of root perforations, is a biocompatible material with numerous clinical applications in endodontics. MTA must be allowed to set in the presence of moisture to optimize the material's physical and chemical properties. In the clinic, occasionally unset MTA has been detected after application of MTA on the tooth, and the reason has been unclear. This case report presents MTA washed-out for several years after placement at the root apex as an apical plug, and discusses the reason and things to consider in clinics.