The universality of lignocellulosic biomass liquefaction by plasma electrolysis under acidic conditions.

In this research, we compared the discharge characteristics and catalytic efficiency of sulfuric acid, p-toluenesulfonic acid, and their respective sodium salts (sodium sulfate and sodium p-toluenesulfonate) in sawdust liquefaction and found that sulfuric acid was the optimal catalyst when glycerol was used as solvent during the plasma electrolytic liquefaction (PEL) process. When sodium p-toluenesulfonate was used as the only catalyst, the liquefaction yield reached 83.51% after 25 min. This yield was higher than that obtained using sodium sulfate as the catalyst (60.63%) because different concentrations of H ions were produced in PEL. Cellulose, lignin, and holocellulose were extracted from sawdust and successfully liquefied in PEL, illustrating the universality of PEL. The optical emission spectra of the different biomass during the PEL process were similar, indicating that the kinds of free radicals produced were similar, which can accelerate the liquefaction of sawdust.

[The study of infrared absorption spectrum of diamond during growth by FTIR].

The diamond thin films were deposited on silicon substrates under invariable conditions of process pressure, substrate temperature negative direct-current (dc) bias of substrate and microwave power while the rations of methane (CH4) to hydrogen (H2) changing from 3% to 5% and 9% using electron-cyclotron-resonance microwave plasma-assisted chemical vapor deposition technique (ECRCVD). In situ Fourier transform infrared spectroscopy (FTIR) have been used to study the plasma species absorbed on the substrate surfaces as well as the species above the substrates surfaces both before and during the nucleation and film growth. It is demonstrated that these techniques can provide useful information on the early stages of diamond growth. When correlated with film properties measured by Raman spectroscopy and scanning electron microscopy, the results from FTIR indicate that the absorption of the graphitic and diamond phases are related to the ratio of CH4 to H2 and can be identified at the early stages of film growth.

Wave dispersion relations in two-dimensional Yukawa systems.

Collective modes in a two-dimensional Yukawa system are investigated by molecular dynamics simulation in a wide range of coupling parameter Gamma and screening strength kappa. The dispersion relations and sound speeds of the transverse and longitudinal waves obtained for hexagonal lattice are in agreement with the theoretical results. The negative dispersion of the longitudinal wave is demonstrated. Frequency gaps are found on the dispersion curves of the transverse wave due to scattering of the waves on lattice defects for proper values of Gamma. The common frequency of transverse and longitudinal waves drops dramatically with the increasing screening strength kappa.