이준영 교수

In the quest for renewable and highly efficient energy storage devices, all-lignin-based flexible supercapacitors are fabricated by integrating cross-linked lignin hydrogel electrolytes with electrospun lignin/polyacrylonitrile nanofiber electrodes.

Electrochemical sodium storage and capture are considered an attractive technology owing to the natural abundance, low cost, safety, and cleanness of sodium, and the higher efficiency of the electrochemical system compared to fossil-fuel-based counterparts. Considering that the sodium-ion chemistry often largely deviates from the lithium-based one despite the physical and chemical similarities, the architecture and chemical structure of electrode materials should be designed for highly efficient

Proportional-integral-derivative (PID) controllers with constant gains seldom meet desired performance when system dynamics rapidly changes due to unknown disturbances. A gain tuning method for variable PID controllers is presented in this paper. First, the equivalence relationship between a discrete PID control and a discrete backstepping control with time-delay estimation and nonlinear damping is clarified, and the variable gains of the PID controller are automatically tuned with a nonlinear d

Dye-sensitized solar cells (DSSCs) with high efficiency have been fabricated using poly(ethylene oxide)/poly(dimethylsiloxane) blend polymer electrolyte with I − /I 3 − redox couple in conjunction with a fabricated nanoporous TiO 2 electrode. The blend complexed with LiI has been found to show conductivity close to 10 −3 S cm −1 at 303 K for [EO]:[Li + ] = 20:1. Detailed studies have been reported on the structural and electrical characterization of the polymer electrolyte. The crystallinity mod

A colorimetric sensor for the detection of citrate ions is reported here using dual-surfactant-capped Ag nanoparticles (dual-AgNP sensor). A mixture of cetyl trimethyl ammonium bromide and a newly prepared gemini nonionic (GFEO) surfactant was used as a capping agent to synthesize dual-surfactant-capped Ag NPs for selective and sensitive citrate detection. The GFEO surfactant was designed with a specific chemical structure to provide strong binding with citrate for selective and sensitive detect

Abstract Interface modulation of nickel phosphide (Ni 2 P) to produce an optimal catalytic activation barrier has been considered a promising approach to enhance the hydrogen production activity via water splitting. Herein, heteronuclei‐mediated in situ growth of hollow Ni 2 P nanospheres on a surface defect‐engineered titanium carbide (Ti 3 C 2 T x ) MXene showing high electrochemical activity for the hydrogen evolution reaction (HER) is demonstrated. The heteronucleation drives intrinsic strai

The adsorption of pyrimidine onto Ge(100) surfaces has been investigated using real-time scanning tunneling microscopy (STM), temperature-programmed desorption (TPD), and density-functional theory (DFT) calculations. Our results show that the adsorbed pyrimidine molecules are tilted about 40 degrees with respect to the Ge surface, and through a Lewis acid-base reaction form bridges between the down-Ge atoms of neighboring Ge dimer rows by double Ge-N dative bonding without loss of aromaticity. F

PURPOSE: Ictal single-photon emission computerized tomography (SPECT) is often nonlocalized in patients with partial epilepsy. We repeated ictal SPECT in patients with partial epilepsy whose first ictal SPECT was nonlocalized. We also performed subtraction ictal SPECT coregistered to magnetic resonance imaging (MRI) (SISCOM) to test the localizability of ictal SPECT. METHODS: We recruited 69 patients with partial epilepsy (33 male and 36 female, mean plus or minus standard deviation age 29.5 ± 1

The kinetics of H2 (D2) desorption from a Ge(100)-2×1:H (D) surface was studied using scanning tunneling microscopy (STM) and temperature programmed desorption (TPD). Inspection of STM images of surfaces at the saturation coverage of H (D) (θH(D)≃1.0 ML) revealed a 2×1 monohydride (monodeuteride) phase in which most H (D) atoms were paired on Ge-dimers. By counting the sites of H2 (D2) desorption in STM images taken after desorption of H2 (D2) at temperatures in the range Ts=500−550 K, the desor

With growing concerns over electronic device malfunction and the resulting information loss caused by electromagnetic interference (EMI), extensive studies have been performed in developing EMI shielding techniques.