Yuanpeng Chen

The Measurement of Permeability of Porous Media with Methane Hydrate

Abstract In this article, the hydrates with different saturations were formed in porous media. The permeability of porous media with the presence of hydrate was measured. Comparison of experiment data with that obtained by theory models showed that the change of absolute permeability in the porous media with a hydrate saturation agreed with the capillary center filled model. The result indicates that hydrates can preferentially form in the capillary center rather than coat the inner wall.

Hexagonal phase-pure wide band gap ε-Ga2O3 films grown on 6H-SiC substrates by metal organic chemical vapor deposition

In this paper, hexagonal structure phase-pure wide-band gap e-Ga2O3 films were grown by metal organic chemical vapor deposition on 6H-SiC substrates. The e-Ga2O3 films with good crystal quality were verified by high-resolution X-ray diffraction. The out-of-plane epitaxial relationship between e-Ga2O3 films and 6H-SiC substrates is confirmed to be e-Ga2O3 (0001)//6H-SiC (0001), and the in-plane epitaxial relationship is also confirmed to be e-Ga2O3 ⟨ 112¯0⟩//6H-SiC ⟨ 112¯0⟩. The SEM and AFM images show that the e-Ga2O3 films are uniform and flat. The e-Ga2O3 films are thermally stable up to approximately 800 °C and begin to transform into β-phase Ga2O3 at 850 °C. Then, they are completely converted to β-Ga2O3 films under 900 °C. The high-quality e-Ga2O3 films with hexagonal structure have potential application in the optoelectronic field.

Mechanical alloying of ceramics in zirconia-ceria system

Abstract In this work, the zirconia and ceria crystalline powders mixture with a composition of ZrO2-30mol.%CeO2 has been subjected to high energy ball milling experiment to investigate whether mechanical alloying is possible in this ceramic system. The structure variation of the powders was followed mainly by X-ray diffraction technique. The result proves that mechanical alloying can occur in ceramic systems.

Mechanical alloying process of the zirconia–8 mol % yttria ceramic powder

The phase transformation process of zirconia–8 mol % yttria powder mixtures during a high energy ball milling process has been studied by means of x‐ray diffraction analysis. It has been found that the m‐ZrO2 (monoclinic zirconia) transforms first to m‐ZrO2 solid solution and then to t‐ZrO2 (tetragonal zirconia) solid solution. Finally, a single cubic zirconia solid solution phase forms after prolonged milling. The structural transformation is discussed and explained in terms of the phase relations in zirconia‐yttria ceramics and the nonequilibrium nature of the mechanical alloying.

The lattice distortion of β-Ga2O3 film grown on c-plane sapphire

The β-Ga2O3 film is grown on c-plane sapphire (Al2O3) substrate using metal organic chemical deposition method. According to high resolution X-ray diffraction measurement results, the epitaxial relationship between β-Ga2O3 film and c-plane sapphire was confirmed. The β-Ga2O3 film is (

Vertically conducting deep-ultraviolet light-emitting diodes with interband tunneling junction grown on 6H-SiC substrate

\overline{2} 01

Synthesis of GaN network by nitridation of hexagonal ε-Ga2O3 film

2¯01) preferred orientation and β-Ga2O3 〈102〉 and 〈010〉 directions are parallel to Al2O3 〈