http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Cho, H.,Kim, E.,Moon, J.,Joo, C.W.,Kim, E.,Park, S.K.,Lee, J.,Yu, B.G.,Lee, J.I.,Yoo, S.,Cho, N.S. Elsevier Science 2017 Organic electronics Vol.46 No.-
Organic wrinkle structures are investigated as an internal scattering layer for the fabrication of highly efficient organic light-emitting diodes (OLEDs). The solution-processed wrinkle structures are planarized with a high-index layer, resulting in a reduced surface roughness and optical haze simultaneously. The OLED device including the wrinkle structures achieved external quantum efficiency (EQE) of 24.2%, corresponding to a 1.24 time enhancement with respect to that of a control device having no internal scattering layer. By attaching a micro lens array (MLA) or a half ball lens (HBL) on the external surface of the substrate, the proposed device exhibits an EQE of 30.5% (1.56 time enhancement) and 41.8% (2.14 time enhancement), respectively. Randomness of the distributed wrinkle structures is shown to provide additional benefits of reduced angular spectral distortion and Lambertian-like emission properties. Trans-scale optical simulation combining wave-optics and the geometrical effect are used for the quantitative analysis of the emission characteristics of the device.
Conformable superoleophobic surfaces with multi-scale structures on polymer substrates
Cho, H.,Jeong, J.,Kim, W.,Choi, D.,Lee, S.,Hwang, W. Royal Society of Chemistry 2016 Journal of materials chemistry. A, Materials for e Vol.4 No.21
<P>The preparation of superoleophobic surfaces has attracted considerable attention, but the practical application of previously reported methods is still difficult owing to the required complicated wafer process and lack of adaptability to any target objects. In this study, we successfully developed a highly conformable superoleophobic surface on a flexible polypropylene film using multi-scale structures and surface functionalization. The multi-scale structures are fabricated via the formation of nanowire arrays and attachment of nanoflakes, realized by inexpensive and easy fabrication processes. Then, after deposition of a fluoroalkylsilane coating, the structured surface shows superoleophobicity with high contact angles and low sliding angles for various liquids with surface tensions as low as 23.8 mN m(-1). We also realized a patterned surface with extremely different wettabilities by tailoring the surface geometry and surface energy. Further, the wetting properties of the fabricated surface were maintained during repeated bending and twisting tests (10 000 cycles) and under shrinkage deformation (epsilon(shrink) = 10%). Thus, the proposed strategy represents a facile method to develop easily adaptable surfaces with special wettabilities.</P>
Cho, H.,Son, M.,Cheon, Y.,Sohn, Y.K.,Kim, J.S.,Kang, H.C. International Association for Gondwana Research 2016 GONDWANA RESEARCH Vol.39 No.-
The Dadaepo Basin is a small Late Cretaceous sedimentary basin in SE Korea, located on the eastern margin of Asia. The basin is an isolated extensional basin situated between the NNE-striking Yangsan and Dongnae faults. The basin-fill sediments, named the Dadaepo Formation, consist of channelized conglomerates and sandstones intercalated with dominantly purple mudstones in the lower part. The upper part is dominated by fine- to coarse-grained tuffaceous sandstones and olive to dark gray mudstones with abundant volcanic interbeds. The formation unconformably overlies dacitic rocks dated at ca. 94Ma and is overlain by basaltic andesite dated at ca. 69Ma (Ar-Ar ages). The overall configuration of the strata of the Dadaepo Formation indicates syndepositional tilting of the basin floor to the north-northeast. A number of outcrop-scale faults are observed in the basin-fill sediments, of which the majority are NW-striking normal faults, including syndepositional growth faults. The orientations of mafic (magmatic) and clastic dikes, interpreted as being approximately contemporaneous with the deposition of the Dadaepo Formation, are also nearly parallel to the strikes of outcrop-scale normal faults. All these extensional structures consistently indicate NE-SW extension of the basin and obliquely intersect the basin-bounding Yangsan and Dongnae faults at angles of 40<SUP>o</SUP>-60<SUP>o</SUP>. It is thus concluded that the Dadaepo Formation was deposited in a pull-apart basin that subsided as a result of NNE-striking sinistral strike-slip faulting in the southeastern part of the Korean Peninsula during the Campanian (Late Cretaceous). This strike-slip faulting was related to north-northwestward oblique subduction of the proto-Pacific (Izanagi/Kula) or Pacific plate under the eastern margin of the Eurasian plate.
Cho, H.,Lee, N.,Kwak, J. Y.,Shin, S. J.,Lee, S. Springer Science + Business Media 2016 Nonlinear dynamics Vol.86 No.3
<P>Recent advance in flapping-wing MAVs has led to greater attention being paid to the interaction between the structural dynamics of the wing and its aerodynamics, both of which are closely related to the performance of a flapping wing. In this paper, an improved computational framework to simulate a flapping wing is developed. This framework is established by coupling a preconditioned Navier-Stokes solution and a co-rotational beam analysis with a restrained warping degree of freedom. Validation of the present framework is performed by a comparison with examples from either earlier analyses or experiments. Further, a numerical analysis of a wing under simultaneous pitching and plunging motion is examined. The results are compared with those obtained with a wing under pure plunging motion, in order to assess the additional motion effect within a spanwise flexible wing. The comparison shows different aerodynamic characteristics induced by the flexibility of the wing, which can be beneficial.</P>
Cho, H.,Joo, H.,Shin, S.,Kim, H. Pergamon Press ; Elsevier Science Ltd 2017 International journal of solids and structures Vol.121 No.-
<P>Co-rotational formulation is one of the approaches applicable to geometrically nonlinear problems in structural analysis. Based on the assumptions of small degree of strain and large displacement, the CR formulation allows an accurate geometrically nonlinear structural analysis. In this paper, an improved CR formulation for dynamic nonlinear analysis is developed for the planar element. Also, extension of the local formulation is conducted for an elastoplastic problem. A simplified approach for planar elastoplastic analyses is proposed by maintaining the original feature of the CR formulation. Moreover, a modified approach in the local formulation is suggested in order to improve the level of accuracy in the plastic state. Contact analysis using the Lagrange multiplier is then implemented. During the present validation procedure of the proposed approaches, four different planar elements are employed. Those elements are investigated with regard to efficiency and accuracy in a general geometrically nonlinear and a geometrically nonlinear/elastoplastic problem, respectively. It is found that the present dynamic formulations gives both accuracy and consistency for all types of the plane element. Also, comparison regarding the choice of the local formulation for the elastoplastic problem is systematically conducted and demonstrated. (C) 2017 Elsevier Ltd. All rights reserved.</P>