Dong Su Lee

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We address the quantum Hall behavior in twisted bilayer graphene transferred from the C face of SiC. The measured Hall conductivity exhibits the same plateau values as for a commensurate Bernal bilayer. This implies that the eightfold degeneracy of the zero energy mode is topologically protected despite rotational disorder as recently predicted. In(More)
OBJECTIVE This study aimed to investigate the regional cerebral dysfunction associated with depressive syndrome in patients with Alzheimer disease (AD). METHOD Twelve patients with AD with depressive syndrome (ADD) and 12 age-, gender-, and severity-matched patients with AD without depressive syndrome (ADND) underwent FDG-PET scanning. The regional(More)
BACKGROUND/AIM This study aimed to identify the functional neuroanatomical correlates of impaired clock drawing test (CDT) performance in patients with Alzheimer's disease (AD). METHOD The CDT was administered to 71 patients with AD, and regional cerebral glucose metabolism (rCMglc) was measured by positron emission tomography (PET). Correlations between(More)
Scalable video coding (SVC) is a new video coding format which provides scalability in three dimensional (SNR-spatio-temporal) space. In this paper, we focus on the adaptation in SNR dimension. Usually, a SVC bitstream may contain multiple spatial layers, and each spatial layer may be enhanced by up to 3 FGS layers. To meet a bitrate constraint, the FGS(More)
Chemically modified graphene was synthesized by chemical vapour deposition (CVD) with ammonia gas introduced during the CVD process. The use of two different metal catalyst films [nickel (Ni) or copper (Cu)] results in distinctly different forms of structural defects in the honeycomb lattice of graphene under identical synthesis conditions. The Ni catalyst(More)
Porous materials have historically been of interest for a wide range of applications in thermal management, for example, in heat exchangers and thermal barriers. Rapid progress in electronic and optoelectronic technology necessitates more efficient spreading and dissipation of the heat generated in these devices, calling for the development of new thermal(More)
Noncontact modulation calorimetry using electromagnetic heating and radiative heat loss under ultrahigh-vacuum conditions has been applied to levitated solid, liquid, and metastable liquid samples. This experiment requires a reduced gravity environment over an extended period of time and allows the measurement of several thermophysical properties, such as(More)
Twisted bilayer graphene offers a unique bilayer two-dimensional-electron system where the layer separation is only in sub-nanometer scale. Unlike Bernal-stacked bilayer, the layer degree of freedom is disentangled from spin and valley, providing eight-fold degeneracy in the low energy states. We have investigated broken-symmetry quantum Hall (QH) states(More)
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