Tao-Hsing Chen

Synthesis and characterization of nanostructured Ba5Ta4O15 by sol–gel process

Hexagonal Ba5Ta4O15 were synthesized by a sol–gel process at temperatures of 700–900xa0°C. The microstructure properties and morphology are studied by X-ray diffraction and scanning electron microscope. Traces of the Ba5Ta4O15 component were detected by energy dispersive X-ray analysis. A higher temperature enhanced higher atom mobility and caused the growth direction to change and created hexagonal square makes obvious good quality of samples. The visible light absorption edges of the Ba5Ta4O15 nanorods and were corresponded to band-gap energies of 4.0xa0eV.

Stress Waves and Characteristics of Zigzag and Armchair Silicene Nanoribbons

The mechanical properties of silicene nanostructures subject to tensile loading were studied via a molecular dynamics (MD) simulation. The effects of temperature on Young’s modulus and the fracture strain of silicene with armchair and zigzag types were examined. The maximum in-plane stress and the corresponding critical strain of the armchair and the zigzag silicene sheets at 300 K were 8.85 and 10.62, and 0.187 and 0.244 N/m, respectively. The in-plane stresses of the silicene sheet in the armchair direction at the temperatures of 300, 400, 500, and 600 K were 8.85, 8.50, 8.26, and 7.79 N/m, respectively. The in-plane stresses of the silicene sheet in the zigzag direction at the temperatures of 300, 400, 500, and 600 K were 10.62, 9.92, 9.64, and 9.27 N/m, respectively. The improved mechanical properties can be calculated in a silicene sheet yielded in the zigzag direction compared with the tensile loading in the armchair direction. The wrinklons and waves were observed at the shear band across the center zone of the silicene sheet. These results provide useful information about the mechanical and fracture behaviors of silicene for engineering applications.

Dynamic Shear Characteristic and Fracture Feature of Inconel 690 Alloy under Different High Strain Rates and Temperatures

The high strain shear rate behaviour of Inconel 690 alloy was investigated by using the split Hopkinson torsional bar. The shear strain rates were tested at 900u2009s−1, 1900u2009s−1, and 2600u2009s−1 and at temperatures of −100°C, 25°C, and 300°C, respectively. It was found that the dynamic shear behaviour of Inconel 690 alloy was sensitive to strain rate and temperature. The fracture shear strain increased with increasing strain rate and temperature. In addition, the strain rate sensitivity was increased with increasing strain and strain rate but decreased with increasing temperature. Finally, the fracture surfaces were found to contain dimple-like features, and the dimple density increased with increasing strain rate and temperature.