Publications by authors named "Seong-Ku Kim"

Organic polymer-based dielectrics with intrinsic mechanical flexibility and good processability are excellent candidates for the dielectric layer of flexible electronics. These polymer films can become even more rigid and electrically robust when modified through cross-linking processes. Moreover, the composites formed by dispersing nanoscale inorganic fillers in a polymer matrix can exhibit further improved polarization property.

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Herein, we report on an unprecedented synthetic method for single-layered GO that takes just a few tens of minutes. This rationally designed solid-state oxidation based on alkali metal carbonates (Li2CO3, Na2CO3, K2CO3) involves a molten salt reaction, which enables the effective exfoliation and oxidation of graphene layers without using H2SO4 and KMnO4. The advantage of this approach is not only the ability to avoid the introduction of strong acid reactants in the reaction process, but this approach also leads to a 4.

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A facile methodology for the large-scale production of layer-controlled MoS layers on an inexpensive substrate involving a simple coating of single source precursor with subsequent roll-to-roll-based thermal decomposition is developed. The resulting 50 cm long MoS layers synthesized on Ni foils possess excellent long-range uniformity and optimum stoichiometry. Moreover, this methodology is promising because it enables simple control of the number of MoS layers by simply adjusting the concentration of (NH ) MoS .

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Complementary combination of heterostructures is a crucial factor for the development of 2D materials-based optoelectronic devices. Herein, an appropriate solution for fabricating complementary dimensional-hybrid nanostructures comprising structurally tailored ZnO nanostructures and 2D materials such as graphene and MoS is suggested. Structural features of ZnO nanostructures hydrothermally grown on graphene and MoS are deliberately manipulated by adjusting the pH value of the growing solution, which will result in the formation of ZnO nanowires, nanostars, and nanoflowers.

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New fiber-type piezoelectric nanogenerator devices consisting of radially aligned perovskite PbTiO nanotubes are designed for energy harvesting from arbitrary mechanical motion. The free-standing fiber-type nanogenerators generate constant amount of electric power by bending or wind motion regardless of direction, thus, extending the possibility of their practical applications.

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It is highly desirable to fabricate liquid crystalline elastomer (LCE) devices with novel functions for applications in different areas. In this study, LCE capillaries with biomimetic peristaltic function are fabricated for the first time to mimic the peristaltic crawling locomotion of earthworms. A specifically designed LC cell was prepared for this purpose, which consisted of two coaxial glass capillaries coated with polyimide alignment layers on the inner cell surfaces.

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Flexible, transparent, and electrically conducting electrode materials are highly desired for flexible electronic applications. With a highly transparent polyimide (PI) as a substrate, a comprehensive and comparative study was performed to investigate four different fabrication schemes in producing transparent and electrically conducting SWCNT/PI electrodes. A very promising method that involves an in situ imidization process and nitric acid doping treatment was identified, which led to the fabrication of highly durable and thermally stable SWCNT/PI electrodes.

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A linearized dual parallel Mach-Zehnder modulator (DPMZM) based on electro-optic (EO) polymer was both fabricated, and experimentally used to suppress the third-order intermodulation distortion (IMD3) in a coherent analog fiber optic link. This optical transmitter design was based on a new EO chromophore called B10, which was synthesized for applications dealing with the fiber-optic communication systems. The chromophore was mixed with amorphous polycarbonate (APC) to form the waveguide's core material.

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Background/aims: Continuous renal replacement therapy (CRRT) has been widely used for treating critically ill patients with acute kidney injury (AKI). Whether CRRT is better than intermittent hemodialysis for the treatment of AKI remains controversial. We sought to identify the clinical features that can predict survival for the patients who are treated with CRRT.

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We demonstrate electro-optic frequency shifting of 1.55-microm optical pulses by as much as 86 GHz in a polymer traveling-wave phase modulator. The optical pulses were modulated with the linear region of quasi-sinusoidal microwave pulses.

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We report on a vertical adiabatic transition between silica planar waveguides and electro-optic (EO) polymer. Gray-scale lithography was used to pattern a polymer transition with an exponential profile. Excess losses of the order of 1 dB were measured, and good mode matching to simulation was observed.

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