Publications by authors named "Hyunggeun Lee"

Novel two-dimensional semiconductor crystals can exhibit diverse physical properties beyond their inherent semiconducting attributes, making their pursuit paramount. Memristive properties, as exemplars of these attributes, are predominantly manifested in wide-bandgap materials. However, simultaneously harnessing semiconductor properties alongside memristive characteristics to produce memtransistors is challenging.

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Topological insulators (TIs) are a new class of materials with gapless boundary states inside the bulk insulating gap. This metallic boundary state hosts intriguing phenomena such as helical spin textures and Dirac crossing points. Here, we theoretically propose RbZnBi and CsZnBi as a new family of TIs exhibiting large bulk band gaps and unique gapless surface states.

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To understand the alkali-metal-dependent material properties of recently discovered AVSb (A = K, Rb, and Cs), we conducted a detailed electronic structure analysis based on first-principles density functional theory calculations. Contrary to the case of A = K and Rb, the energetic positions of the low-lying Van Hove singularities are reversed in CsVSb, and the characteristic higher-order Van Hove point gets closer to the Fermi level. We found that this notable difference can be attributed to the chemical effect, apart from structural differences.

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Aim: To compare survival between bile duct segmental resection (BDSR) and pancreaticoduodenectomy (PD) for treating distal bile duct cancers.

Methods: Retrospective analysis was conducted for 45 patients in a BDSR group and for 149 patients in a PD group.

Results: The T-stage (P < 0.

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Conversion of oximes to the carbonyl compounds has been demonstrated with use of 2-nitro-4,5-dichloropyridazin-3(2H)-one (2) under microwave irradiated conditions. Fourteen aliphatic and aromatic oximes converted to their corresponding aldehydes and ketones in good to excellent yields. It is noteworthy that the reaction is conducted under neutral, mild, and eco-friendly condition.

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Objectives: We aimed to compare different techniques using the definitions of the International Study Group of Pancreatic Surgery for postoperative complications after pancreaticoduodenectomy.

Methods: The perioperative data of 119 patients that underwent pancreaticoduodenectomy by a single surgeon were retrospectively analyzed. Pancreaticojejunal anastomosis was performed using the dunking method (n = 39), the duct-to-mucosa anastomosis method (n = 40), and the duct-to-mucosa adaptation (n = 40).

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TBAF-assisted N-arylation and benzylation of benzazoles such as 1H-benzimidazole, 1H-indole, and 1H-benzotriazole with aryl and benzyl halides have been demonstrated under the ligand/base/solvent-free conditions. In the presence of CuBr2 and TBAF (n-Bu4NF), the azoles underwent N-arylation and benzylation with aryl and benzyl halides smoothly in moderate to good yields. It is noteworthy that the reaction is conducted under the ligand/base/solvent-free conditions.

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