Abstract: The present application relates to the technical field of architectural engineering. Disclosed are a slab joint leakage-proof structure of a prefabricated roof panel, a prefabricated roof panel and a prefabricated roof panel system. The slab joint leakage-proof structure comprises a first leakage-proof layer. The first leakage-proof layer comprises two flexible structures which abut against each other and are arranged at the joint of a main rib on the long side of the roof panel and a main rib on the long side of an adjacent roof panel. Either of the flexible structures comprises a main body portion sealably attached to the main rib, and at least one protruding portion which is fixedly disposed on the main body portion, protrudes and extends into the joint, and can tightly abut against the other flexible structure. The protruding portions of the two flexible structures can enclose an air cavity layer sealably isolated from the outside.

Abstract: Composite phase structure of early transition metal-based metallic alloys, including those of crystalline, quasicrystalline and amorphous phases, can be obtained in a controllable way upon direct (in-situ) cooling (solidification) of the alloy, realized either by adjusting the alloy compositions at a fixed cooling rate or by changing the cooling rates for a given alloy composition. Some embodiments are based on the addition of later transition metals, mainly of Cu with Ni or Fe with Co in early transition metal based (mainly Ti and Zr or Hf and Nb) metallic alloys. If cooling rate is on the scale of 103° C./s, a wholly amorphous structure is obtained for most of the compositions. At reduced cooling rates, composite structures with different kinds of phases can be achieved, as illustrated graphically in FIG. 1. Nickel addition promotes the formation of quasicrystalline phases, especially for Ti-rich alloy compositions with beryllium.

Abstract: The present invention relates to novel calcium based amorphous alloys with high thermal stability and low mass density represented by the general formula: CaAlQ, wherein Q represents one or more elements selected from the group consisting of Cu, Ag, Zn and Mg. Typically, the atomic percentage of the calcium is about 50%.