Weimin Du

Light-scattering studies of the liquid-glass transition of ${\mathrm{Ca}}_{0.4}$${\mathrm{K}}_{0.6}$(${\mathrm{NO}}_{3}$${)}_{1.4}$ have been carried out from 305 to 23\ifmmode^\circ\else\textdegree\fi{}C. Composite spectra covering over four decades in frequency were obtained by combining data obtained with a Sandercock tandem Fabry-P\'erot interferometer and Raman spectra. Two-step relaxation processes were observed in the supercooled liquid near the glass transition. The \ensuremath{\alpha} relaxation exhibits a temperature-independent stretching for T>${\mathit{T}}_{\mathit{c}}$ with ${\mathit{T}}_{\mathit{c}}$\ensuremath{\approxeq}105 \ifmmode^\circ\else\textdegree\fi{}C, which is about 45\ifmmode^\circ\else\textdegree\fi{}C above the glass transition temperature. The \ensuremath{\beta}-relaxation frequency scale indicates critical slowing down when the temperature approaches ${\mathit{T}}_{\mathit{c}}$ from either above or below. Scaling analyses for both \ensuremath{\alpha} and \ensuremath{\beta} relaxations provide good agreement with the predictions of mode-coupling theory.

CoNi₂S₄/graphene nanocomposite electrodes exhibit excellent pseudocapacitance behavior enhanced by synergistic effect, demonstrating the nanocomposite's promise as an electrode material for high-performance supercapacitors.

The liquid-glass transition dynamics of the molecular glass Salol has been studied by light-scattering spectroscopy from 383 to 198 K. Analysis of wide-frequency-range composite spectra revealed the relaxation dynamics from 0.2 GHz to 3.5 THz. A two-step relaxation process was observed near the crossover temperature ${\mathit{T}}_{\mathit{c}}$\ensuremath{\sim}256 K which is about 40 K above the glass-transition temperature ${\mathit{T}}_{\mathit{g}}$. The \ensuremath{\beta}-relaxation process is well described by the scaling predictions of the mode-coupling theory in both the liquid and glass states. The \ensuremath{\alpha} relaxation obeys the time-temperature superposition principle for T>${\mathit{T}}_{\mathit{c}}$. The light-scattering results, when combined with previous dielectric measurements, indicate a continuous evolution of the relaxation time and stretching of the \ensuremath{\alpha} process from the liquid to the glass state. Qualitative and quantitative comparisons of the experimental results with the predictions of the mode-coupling theory and the configuration-space percolation theory are presented.

Hybrid asymmetric supercapacitors based on Ni_0.85Se nanosheet arrays and activated carbon show remarkable energy-storage characteristics and promising applicable value.