• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1203-1205
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• 2007

Confinement of charge carrier and exciton is the essential factor for enhancing the efficiency and stability of the electrophosphorescent devices. The interplay between the properties of emitters and other adjacent layers are studied based on the physical interpretation with difference of energy level, charge carrier mobility, and corresponding charge-trapping behavior.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.617-620
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• 2003

This paper presents the confinement effect of transverse reinforcement and cross-tie in hollow rectangular sectional columns. 20 analytical models with different amounts of transverse reinforcement and cross-tie in a plastic hinge region were analyzed by 3D nonlinear FEM. The analytical results show that the higher ductility can be achieved by the resonable combination of transverse re-bar and cross-tie providing sufficient lateral confinement.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.937-942
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• 2003

Three series of 36 short circular columns confined by wraps, full shells and partial shells were tested by varying the thickness of GFRP laminates. An assessment of the effectiveness of the existing models on confinement of concrete columns with FRP was made for present tests. Test results indicated significant increases in strength and deformability compared with those in unconfined concrete, particularly warp and full shell confinement. Existing predictive equations for peak strength and strain of confined concrete showed a large scatter and varied considerably, resulting from the realistic fracture strains of FRP nor considered.

• Journal of Information Processing Systems
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• v.9 no.2
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• pp.189-204
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• 2013

The confinement problem was first noted four decades ago. Since then, a huge amount of efforts have been spent on defining and mitigating the problem. The evolution of technologies from traditional operating systems to mobile and cloud computing brings about new security challenges. It is perhaps timely that we review the work that has been done. We discuss the foundational principles from classical works, as well as the efforts towards solving the confinement problem in three domains: operating systems, mobile computing, and cloud computing. While common issues exist across all three domains, unique challenges arise for each of them, which we discuss.

• Carbon letters
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• v.17 no.1
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• pp.29-32
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• 2016

This paper addresses the effect of dopants on the electronic properties of zigzag (8, 0) semiconducting single walled carbon nanotubes (SWCNTs), using extended Hückel theory combined with nonequilibrium Green’s function formalism. Through appropriate dopant concentrations, the electronic properties of SWCNTs can be modified. Within this context, we present our ongoing investigation on (8, 0) SWCNTs doped with nitrogen. Quantum confinement effects on the electronic properties of the SWCNTs have also been investigated. The obtained results reveal that the electronic properties of SWCNTs are strongly dependent on the dopant concentration and modification of electronic structures by hydrogen confinement.

• Journal of the Korean Ceramic Society
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• v.55 no.6
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• pp.515-526
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• 2018

Cesium lead halide ($CsPbX_3$) nanocrystals have emerged as a new family of semiconductor nanomaterials that can outperform existing semiconductor nanocrystals owing to their superb optical and charge transport properties. Although these materials are expected to have many superior properties, control of the quantum confinement and isoelectronic magnetic doping, which can greatly enhance their optical, electronic, and magnetic properties, has faced significant challenges. These obstacles have hindered full utilization of the benefits that can be obtained by using $CsPbX_3$ nanocrystals exhibiting strong quantum confinement or coupling between exciton and magnetic dopants, which have been extensively explored in many other semiconductor quantum dots. Here, we review progress made during the past several years in tackling the issues of introducing controllable quantum confinement and doping of $Mn^{2+}$ ions as the prototypical magnetic dopant in colloidal $CsPbX_3$ nanocrystals.

• International Journal of Concrete Structures and Materials
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• v.18 no.2E
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• pp.133-142
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• 2006

An experimental study was conducted to investigate the effectiveness of transverse steel in reinforced concrete tied columns subjected to monotonically increasing axial compression. Eighteen large-scale columns($260{\times}260{\times}1,200mm$) were tested. Effects of such main variables as concrete compressive strength, configurations of transverse steel, transverse reinforcement ratio, spacing of transverse steel, and spalling of concrete cover were investigated. High-strength concrete columns under concentric axial loads show extremely brittle behavior unless the columns are confined with transverse steel that can provide sufficiently high lateral confinement pressure. A consistent decrease in the deformability of the column test specimens was observed with increasing concrete strength. Test results of this study were compared with existing confinement models of modified Kent-Park, Sheikh-Uzumeri, Mander, and Saatcioglu-Razvi. The comparison indicates many existing models to predict the behavior of confined concrete overestimate or underestimate the ductility of confined concrete.

• Computers and Concrete
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• v.19 no.1
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• pp.41-49
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• 2017

The use of external carbon-fiber-reinforced polymer (CFRP) wraps is one of the most effective techniques existing for the confinement of the circular concrete columns. Currently, several researches have been made to develop models for predicting the behavior of this type of confinement. The disadvantage of the most models, is to not take into account the contribution of the transverse steel reinforcements (TSR) effect, However, very limited models have been recently developed that considers this combined effect and gives less accurate results. This paper presents the development of a new model for the axial behavior of circular concrete columns confined by combining external CFRP warps-and-internal TSR (hoops or spirals) based on the existing experimental data. The comparison between the proposed model and the experimental results showed good agreement comparing to the several existing models. Moreover, the expressions of estimating the ultimate strength and the corresponding strain are simple and precise, which make it easy to use in the design applications.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.286-289
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• 2006

Headed bars have used to the anchoring of the tension or compression longitudinal bars and of the shear reinforcing bars. Recently, lap splices of headed bars are attempted to the joints of precast concrete members and to the connections between old and new concrete members. Previous Michael's experimental research showed that confinement details had an effect on the lap splice performances of headed bars. In this study, the lap splice performances of headed bars(D25) with lap length and confinement details are evaluated through the experimental works. Four specimens, of which variables were the lap length of headed bar and the type of confine details, were tested for the performance evaluation on lap splice. Test results show that the lap length confinement reinforcement improve the performance of lap splice.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.604-607
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• 2003

Recently, hybrid concrete structures such as a concrete-filled steel tubular(CFT), a steel reinforced concrete(SRC) and a composite material are popular in structure applications. They also have merit of high strength, high ductility, and large energy absorption capacity. But the analysis of hybrid concrete structures is very difficult owing to the complex behavior of concrete under passive confinement. This paper has analyzed CFT, which receives passive confinement using Tri-Surface concrete model for three dimension finite element analysis. By the result of that, the proposed model was properly forecasted a concrete behavior that receives passive restraint as well as non-linear analysis of concrete which receive uniaxial stress and high active confinement of 400Mpa. If the model through the steady study is set up especially on the factor of concrete under passive confinement, the proposed concrete model will be surely useful for analysis of the hybrid concrete structures.