김훈 교수

A fused-deposition modeling (FDM) 3D-printed polyethylene terephthalate glycol (PETG)-sepiolite composite showed effective synergetic mechanical reinforcement in tensile testing compared to an injection-molded composite. The results showed that the addition of 3 phr sepiolite improved the tensile strength of 3D-printed PETG samples by 35.4%, while the tensile strength of injection-molded PETG samples was improved by 7.2%. To confirm these phenomena, FDM PETG-sepiolite composites were investigate

Cross-linking is an essential element in enhancing polymers’ mechanical properties in adhesives, elastomers, and hydrogels. However, covalent cross-linking introduces a trade-off relationship between cohesive interactions and chain mobility of polymers, thus restricting stretching and adhesion properties. Herein, a supramolecular cross-linker is synthesized by giving an acrylate functional group to β-cyclodextrin. The supramolecular cross-linker shows a sliding effect in polymers with a threaded

The electromigration resistance of ultra-large scale integration (ULSI) Cu interconnects can be improved by inserting an adhesion promoter between Cu and the diffusion barrier. A metallurgical survey was accomplished to select the element having a good Cu adhesion property. For adoption as an interconnect material, it should have a low resistivity and should not react with Cu to avoid increasing the resistance of Cu interconnects. Ru, Os, Mo, W, and Ta satisfied the above conditions. The Cu adhe

Cu seed layers for future interconnects must have conformal step coverage, smooth surface morphology, and strong adhesion. Conformal deposition had been achieved by chemical vapor deposition (CVD), but CVD Cu films have rough surfaces and poor adhesion. In this paper, conformal, smooth, adherent, continuous, and thin Cu films were made by CVD. CuON was deposited from a Cu-amidinate precursor, , and at 140– on Ru. Crystallites in the deposited film have either a or structure depending on the rati

In VO2, the explicit origin of the insulator-to-metal transition is still disputable between Peierls and Mott insulators. Along with the controversy, its second monoclinic (M2) phase has received considerable attention due to the presence of electron correlation in undimerized vanadium ions. However, the origin of the M2 phase is still obscure. Here, we study a granular VO2 film using conductive atomic force microscopy and Raman scattering. Upon the structural transition from monoclinic to rutil

Ru was evaluated as a new underlayer material for depositing ultrathin chemical vapor deposited (CVD) Cu seed layers, and the morphology and adhesion property of CVD Cu films on Ru were compared to that of Ta. CVD Cu films deposited on Ru showed higher nuclei density than Cu films deposited on Ta. Relatively low deposition temperatures of and high precursor partial pressures of yield high density of Cu nuclei. Smooth, thick, continuous CVD Cu seed layers were deposited onto Ru underlayers at thi

The effect of Ru crystal orientation on the deposition behavior of chemical vapor deposition (CVD) Cu was investigated. The crystal orientation of Ru films was modulated by adjusting sputtering temperature. Ru(001) and random orientation films were obtained by sputtering at 300 °C and room temperature, respectively. CVD Cu on Ru with the (001) crystal orientation had a smooth morphology and a strong (111) peak. However, CVD Cu on the Ru film with the random orientation had a rough surface and a

Rod-coil oligomers consisting of tetraaniline and alkyl chains were synthesized and their self-assembly behavior was studied in their two different oxidation states, namely the leucoemeraldine base (LEB) and the emeraldine base (EB) states. In solutions of oligomers in the EB state, two positional isomers and cis/trans (E/Z) isomers were observed in ratios of 70 : 30 and 50 : 50, respectively. The rod-coils readily crystallized into bilayered smectic-like crystals, while their detailed crystalli

Maxillary expansion via segmental Le Fort I osteotomy showed good stability, with a skeletal relapse rate of 26.3% over approximately 12 months. Our results suggest that a greater amount of expansion requires greater efforts for the prevention of relapse.