The energy levels of defect states in nanometer-sized amorphous silicon nitride solids were systematically studied in terms of ultraviolet emission spectra. Six emission bands were observed, corresponding to 3.2, 2.8, 2.7, 2.4, 2.3, and 2.0 eV, respectively. With increasing the heat-treated temperature from room temperature to 1000 °C in low vacuum, these emission bands became high. For the specimen heated at 1000 °C, a new emission band of 3.0 eV appeared. The appearance of these emission bands is closely related to the formation of the energy levels of the defect states in the energy gap. The origin of these emission bands are discussed in detail.

The first EAST (Experimental Advanced Superconducting Tokamak) plasma ignited in 2006 with non-actively cooled steel plates as the plasma-facing materials and components (PFMCs) which were then upgraded into full graphite tiles bolted onto water-cooled copper heat sinks in 2008. The first wall was changed further into molybdenum alloy in 2012, while keeping the graphite for both the upper and lower divertors. With the rapid increase in heating and current driving power in EAST, the W/Cu divertor project was launched around the end of 2012, aiming at achieving actively cooled full W/Cu-PFCs for the upper divertor, with heat removal capability up to 10 MW m−2. The W/Cu upper divertor was finished in the spring of 2014, consisting of 80 cassette bodies toroidally assembled. Commissioning of the EAST upper W/Cu divertor in 2014 was unsatisfactory and then several practical measures were implemented to improve the design, welding quality and reliability, which helped us achieve successful commissioning in the 2015 Spring Campaign. In collaboration with the IO and CEA teams, we have demonstrated our technological capability to remove heat loads of 5000 cycles at 10 MW m−2 and 1000 cycles at 20 MW m−2 for the small scale monoblock mockups, and surprisingly over 300 cycles at 20 MW m−2 for the flat-tile ones. The experience and lessons we learned from batch production and commissioning are undoubtedly valuable for ITER (International Thermonuclear Experimental Reactor) engineering validation and tungsten-related plasma physics.

Thin films of V 2 O 3 with thickness of 215 nm were grown on a-and c-plane sapphire by pulsed laser deposition with ͑001͒V 2 O 3 ʈ ͑001͒Al 2 O 3 and ͑110͒V 2 O 3 ʈ ͑110͒Al 2 O 3 epitaxy. The effects of the growth direction on the electrical resistivity of the films were examined. Films on c-plane sapphire displayed a metal-to-insulator transition at T = 180 K compared to T = 160 K in single-crystal V 2 O 3 . The films on a-plane sapphire, however, showed an insulator-to-insulator transition at T = 186 K. The variation in the phase transformation characteristics and the resistivity can be attributed to different levels of strain and commensurate changes in the film morphology.

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