Daejeon, South Korea
Daejeon, South Korea

Daeduk College is a private technical college in the Yuseong-gu district of Daejeon, a major city of South Korea. The current president is Han Sung-dong . The college employs about 100 instructors. Wikipedia.


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Lim J.M.,Daeduk College
International Journal of Automotive Technology | Year: 2017

Lumped Mass-Spring (LMS) model is simple but very effective for the design study of vehicle crashworthiness and occupant safety. To construct the LMS model, the SISAME software and the NHTSA test data were used. Using the SISAME, the weights of mass elements and the load-paths of spring elements were optimally and directly extracted from the test data. Among the various types of spring, the segmented inelastic type of spring was effective for the vehicle crash analysis. In this study, to obtain the occupant injuries such as HIC15 and 3 ms Chest g’s, the LMS model containing the occupant model consisted of the head, chest and pelvis was developed and validated. The modeling for the chest deflection and neck injuries was not considered in this study because of the modeling difficulties and the limitation of the SISAME software. The simulation results of occupants showed good agreements with the test results. The modeling idea for the occupant was simple but very effective. © 2017, The Korean Society of Automotive Engineers and Springer-Verlag Berlin Heidelberg.


Ambade S.B.,Chonbuk National University | Ambade R.B.,Chonbuk National University | Lee W.,Daeduk College | Yoon S.C.,Korea Research Institute of Chemical Technology | Lee S.-H.,Chonbuk National University
Nanoscale | Year: 2014

This work reports on inverted polymer solar cells (IPSCs) based on highly transparent (>95%), hydrophobic, seedless ZnO nanorods (NRs) as cathode buffers with extremely enhanced electrical characteristics. The transparent NR suspension with stability for more than a year is achieved by adding a small amount of 2-(2-methoxyethoxy) acetic acid (MEA). The ability of the stable nanorod suspension to easily spin-coat is certainly an advance to the fabrication of films over large areas and to replace the conventional seeding method to grow one-dimensional nanostructures for use in optoelectronic devices. We observe a strong correlation between the photovoltaic performance and the transparency of ZnO NRs. IPSCs using poly-3-hexylthiophene (P3HT) and [6,6]-phenyl C60 butyric acid methyl ester (PCBM) mixtures in the active layer and transparent (MEA-capped) ZnO NRs as cathode buffers exhibit a power conversion efficiency of 3.24% under simulated AM 1.5G, 100 mW cm-2 illumination. © 2014 the Partner Organisations 2014.


Jeong B.-W.,Daeduk College | Kim H.-Y.,Chungbuk National University
Computational Materials Science | Year: 2013

Various failure behaviors of closed single-walled carbon nanotubes fully filled with C60 fullerenes under compressive, tensile, torsional, and combined tensile-torsional loads are examined using classical molecular dynamics simulations. In particular, the details of multiple failure modes in combined tension-torsion are investigated, and then multiple failure envelopes are identified as failure criteria. In the cases of uniaxial loading, filling the nanotubes with C60 fullerenes importantly increases their compressive and torsional buckling loads (not tensile failure loads), and the rate of increase is much higher in torsional loading. The observations under combined tensile-torsional loading reveal that while the tensile failure load decreases with combined torsion, the torsional buckling load increases with combined tension. As the result, the failure envelopes under this type of combined loading are definitely different relative to what is predicted under uniaxial tension or torsion, and exhibit the feature of multiple failure envelopes that consist of both tensile and torsional failure envelopes. © 2013 Elsevier B.V. All rights reserved.


Jeong B.-W.,Daeduk College | Kim H.-Y.,Chungbuk National University
Physica E: Low-Dimensional Systems and Nanostructures | Year: 2015

This work examines the torsional mechanical properties of single-walled carbon nanotubes with tensile pre-strains using classical molecular dynamics simulations. In particular, it is investigated how much the tensile pre-strains enhance the torsional stability of nanotubes, and how this enhanced torsional stability is dependent on the chirality of nanotubes. The observations reveal that the tensile pre-strains greatly enhance the torsional stability of nanotubes and the effects are strongly dependent on the degrees of tensile pre-strains and the chirality of nanotubes. The increase rates of torsional buckling moments are in proportion to the degrees of tensile pre-strains and much larger in zigzag nanotubes than in armchair nanotubes. In the case of zigzag nanotubes, the maximum increase rate of torsional buckling moment is 122.3% for the tensile pre-strain of 0.115. In addition, the tensile pre-strains also alter the torsional stiffness of nanotubes depending on the degrees of tensile pre-strains and the chirality of nanotubes. © 2014 Elsevier B.V. All rights reserved.


Jeong B.-W.,Daeduk College | Kim H.-Y.,Chungbuk National University
Physica E: Low-Dimensional Systems and Nanostructures | Year: 2013

Transitional failure envelopes of hybrid single-walled carbon nanotubes functionalized by functional groups and filled with butane molecules under combined tension-torsion are predicted using classical molecular dynamics simulations. The observations reveal that while the tensile failure load decreases with combined torsion, the torsional buckling moment increases with combined tension. As a result, the failure envelopes under combined tension-torsion are definitely different from those under pure tension or torsion. In such combined loading, there is a multitude of failure modes (tensile failure and torsional buckling), and the failure therefore exhibits the feature of transitional failure envelopes. In addition, the functionalization by functional groups decreases both tensile failure load and torsional buckling moment, while filling with butane molecules increases only the torsional buckling moment. Consequently, the transitional failure envelopes of functionalized and filled nanotubes are absolutely different relative to what is predicted for pristine nanotubes. © 2013 Elsevier B.V.


Jeong B.-W.,Daeduk College | Kim H.-Y.,Chungbuk National University
Physica Status Solidi (A) Applications and Materials Science | Year: 2013

This work examines the size-dependent elastic and failure properties of single-walled carbon nanotubes (CNTs) with various aspect ratios under simultaneously combined tensile-torsional loads that can widely occur on the nanotubes incorporated in nanometer-scale devices and composite materials; classical molecular dynamics simulations are used. In particular, the effects of coupling between combined loads are investigated carefully, and then the size-dependent failure properties and multiple failure modes are characterized with failure criteria like multiple failure envelopes. These multiple failure modes consist of both the tensile fracture and torsional instability that refer to any actions leading to an inability of CNTs. The observations reveal that while the tensile failure load decreases with combined torsion, the torsional buckling load and shear stiffness increase with combined tension. These effects are due to the coupling between combined loads, and strongly dependent on the size and chirality of CNTs and the ratios of combined loading. This result therefore establishes the multiple failure envelopes, which are definitely different relative to what is predicted under uniaxial tension or torsion. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Lee D.Y.,Hanyang University | Shinde D.V.,Hanyang University | Yoon S.J.,Hanyang University | Cho K.N.,Hanyang University | And 3 more authors.
Journal of Physical Chemistry C | Year: 2014

In the present study, a thin layer of Cu-based metal-organic frameworks (MOFs, copper(II) benzene-1,3,5-tricarboxylate) is fabricated using a layer-by-layer technique, and the layer is investigated as a light-absorbing layer in TiO2-based solar cells. Iodine doping of the MOFs is performed to improve the conductivity and charge-transfer reaction across the TiO2/MOF/electrolyte interface. The HOMO and LUMO energy states of the MOF films are estimated to be -5.37 and -3.82 eV (vs vacuum), respectively, which show a well-matched energy cascade with TiO2. For the first time, a TiO2-based solar cell is fabricated successfully using iodine-doped Cu-MOFs as an active layer, demonstrating a cell performance with Jsc = 1.25 mA cm-2 and Eff = 0.26% under illumination of 1 sun radiation. In contrast, the cell with an undoped MOF layer exhibited J sc = 0.05 mA cm-2 and Eff = 0.008%. Electrochemical impedance spectroscopy of the cells suggests that iodine doping significantly reduces the charge-transfer resistance. © 2013 American Chemical Society.


Kim G.-H.,Daeduk College
Transactions on Electrical and Electronic Materials | Year: 2015

In this study, the characterizations of oxide contact hole etching are investigated with C4F8/O2/Ar and CH2F2/C4F8/O2/ Ar plasma. As the percent composition of C4F8 in a C4F8/O2/Ar mixture increases, the amount of polymer deposited on the etched surface also increases because the CxFy polymer layer retards the reaction of oxygen atoms with PR. Adding CH2F2 into the C4F8/O2/Ar plasma increases the etch rate of the oxide and the selectivity of oxide to PR. The profile of contact holes was close to 90°, and no visible residue was seen in the SEM image at a C4F8/(C4F8+O2) ratio of 58%. The changes of chemical composition in the chamber were analyzed using optical emission spectroscopy, and the chemical reaction on the etched surface was investigated using X-ray photoelectron spectroscopy © 2015 KIEEME. All rights reserved.


Cho H.-J.,Daeduk College | Lee J.-P.,Node Engineering
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2014

In this study, we developed lightweight LED fluorescent lamp using thermally conductive engineering PC a heat sink instead of metal. In order to secure price competitiveness, we used double extrusion molding which extrude both the heat sink plate and diffuser plate simultaneously. Fabricated fluorescent lamp has less than 20% of weight as compare to glass fluorescent lamp and power consumption is 20.2 watts, luminous efficiency 123.9 lm/W, respectively. Despite the heat conductive plastic is adopted, the system temperature is maintained less than 35? and the thermal resistance is 25 °C/W. © 2014 SPIE.


Jeong B.-W.,Daeduk College
Journal of Nanomaterials | Year: 2012

Transitional failure envelopes of single- and double-walled carbon nanotubes under combined tension-torsion are predicted using classical molecular dynamics simulations. The observations reveal that while the tensile failure load decreases with combined torsion, the torsional buckling moment increases with combined tension. As a result, the failure envelopes under combined tension-torsion are definitely different from those under pure tension or torsion. In such combined loading, there is a multitude of failure modes (tensile failure and torsional buckling), and the failure consequently exhibits the feature of transitional failure envelopes. In addition, the safe region of double-walled carbon nanotubes is significantly larger than that of single-walled carbon nanotubes due to the differences in the onset of torsional buckling. © 2012 Byeong-Woo Jeong.

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