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The sapphire single crystal plate with size of 485 mm x 985 mm x 12 mm was successfully prepared by a large-size edgedefined film-fed growth (EFG) furnace designed and developed independently. After cutting and grounding, the crystal was formed into transparent armors composited with glass and polycarbonate. The surface density with the size of 352 mm x 351 mm x 33 mm is 79. 27 kg/m², and the surface density of the other is 79.38 kg/m² with the size of 351 mm x 342 mm x 33 mm. Targeting tests were conducted on the transparent armors using incendiary shells with diameters of 7.62 mm and 12.7 mm, respectively. The experimental results show that the transparent armor based on sapphire crystal plate has excellent impact resistance during firing at a normal angle of 0° and with a distance of 100 m which from target to the armors. [ABSTRACT FROM AUTHOR]

Vapor equilibrium transport method is used to prepare near stoichiometric lithium tantalate crystals with high quality. However, it is difficult to prepare large-thickness crystals by this method due to its low solid diffusion rate. In this paper, based on the diffusion mechanism of lithium tantalate crystal, the diffusion of lithium tantalate crystal was carried out by asymmetric diffusion process with lithium rich atmosphere on one side of the wafer and congruent composition atmosphere on the other side. The composition and domain inversion field were characterized. The results show that the asymmetric diffusion technique provides a channel for the diffusion of anti-tantalum ion and increases the diffusion rate of anti-tantalum ion and lithium ion in the crystal, which is beneficial to the preparation of large-thickness near stoichiometric lithium tantalate crystal. [ABSTRACT FROM AUTHOR]