舌头添高潮A级毛片,亚洲欧美一区二区三区日产,永久黄网站色视频免费,色老汉网站色老汉影院18禁止

Belonging to hexagonal system, the Sapphire crystal is a simple oxide crystal with coordination type and a refractory oxide crystal with high melting point. With high mechanical strength, high temperature refractoriness and excellent chemical stability, it is an excellent laser host material, window material for various optical components, infrared devices, and high-intensity laser, and the most commonly used LED semiconductor lighting substrate material. It is also the most widely used synthetic single crystal material so far.