Abstract: The present disclosure provides a cobalt-free and nickel-free positive electrode material and a preparation method therefor, and a battery. The preparation method includes: preparing a cobalt-free and nickel-free matrix material, and mixing the cobalt-free and nickel-free matrix material, a lithium source, and a divalent manganese compound for reaction to obtain the cobalt-free and nickel-free positive electrode material. By adding the divalent manganese compound, the generation of lamellar LiMnO2 and spinel LiMn2O4 is inhibited, the generation of lamellar Li2MnO3 is promoted, and the cycle performance of the material is improved.

Abstract: Provided are a phytase mutant and a coding DNA molecule thereof, a vector, and a host cell. The phytase mutant comprises an amino acid sequence having at least 90% identity with SEQ ID NO: 3, and compared with SEQ ID NO: 3, and contains an amino acid substitution at at least one position selected from the group consisting of 36, 126, 211, 253, 258, and 266. The heat resistance of the mutant is significantly improved, thus facilitating the wide application of phytase in feed.

Abstract: The present disclosure provides an opening-closing type microwave catalytic reaction apparatus, including a microwave system, a microwave cavity, a protective cover, a cooling system, and a vertical furnace tube, where two ends of the furnace tube are respectively stretched out of the microwave cavity, the microwave system includes a plurality of microwave transmitting units, and the microwave transmitting unit includes a microwave transmitter; the furnace tube is provided with a gas inlet on a top and a gas outlet on a bottom; a compression hinge and a cavity cover capable of being opened or closed are arranged on the microwave cavity, a convex edge plate is disposed at an edge of the cavity cover, the compression hinge can compress the cavity cover such that the convex edge plate is tightly attached to a concave edge plate on the microwave cavity, and the protective cover can cover the entire cavity cover.

Abstract: The present disclosure provides an opening-closing type microwave catalytic reaction apparatus, including a microwave system, a microwave cavity, a protective cover, a cooling system, and a vertical furnace tube, where two ends of the furnace tube are respectively stretched out of the microwave cavity, the microwave system includes a plurality of microwave transmitting units, and the microwave transmitting unit includes a microwave transmitter; the furnace tube is provided with a gas inlet on a top and a gas outlet on a bottom; a compression hinge and a cavity cover capable of being opened or closed are arranged on the microwave cavity, a convex edge plate is disposed at an edge of the cavity cover, the compression hinge can compress the cavity cover such that the convex edge plate is tightly attached to a concave edge plate on the microwave cavity, and the protective cover can cover the entire cavity cover.