Dong Su Lee

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Large-area single crystal monolayer graphene is synthesized on Ni(111) thin films, which have flat terraces and no grain boundaries. The flat single-crystal Ni films are heteroepitaxially grown on MgO(111) substrates using a buffer layer technique. Low-energy electron diffraction and various spectroscopic methods reveal the long-range single crystallinity(More)
Raman spectra were measured for mono-, bi-, and trilayer graphene grown on SiC by solid state graphitization, whereby the number of layers was preassigned by angle-resolved ultraviolet photoemission spectroscopy. It was found that the only unambiguous fingerprint in Raman spectroscopy to identify the number of layers for graphene on SiC(0001) is the line(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)
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)
It is still unclear whether apolipoprotein E epsilon 4 (APOE E4) influences the cerebral glucose metabolism abnormalities found in Alzheimer's disease (AD), although APOE E4 is a well-known risk factor for AD. [(18)F]Fluorodeoxyglucose PET was conducted in patients with very mild (n=17), mild (n=27), and moderate-to-severe (n=19) AD. The presence of APOE E4(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)
Coherent motion of electrons in Bloch states is one of the fundamental concepts of charge conduction in solid-state physics. In layered materials, however, such a condition often breaks down for the interlayer conduction, when the interlayer coupling is significantly reduced by, e.g., a large interlayer separation. We report that complete suppression of(More)
Transport measurements normally provide a macroscopic, averaged view of the sample so that disorder prevents the observation of fragile interaction-induced states. Here, we demonstrate that transconductance fluctuations in a graphene field effect transistor reflect charge localization phenomena on the nanometer scale due to the formation of a dot network(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)
We have developed a method to fabricate crossed junctions between semiconducting (s) and metallic (m) carbon nanotubes (CNTs) combining electric field directed chemical vapor deposition growth and dielectrophoretic alignment. By separating the s- and m-CNTs with a thin dielectric an ultra-small field effect transistor (FET) was fabricated. By using the(More)