Abstract: A modified polyamide is provided, which has a structure of formula (1), in which a+c is 3-8, b is 8-40, m is 3-11, n is 2-16, x is 100-220, and y is 1-6. A method of preparing a modified polyamide is also provided, which includes copolymerizing C4-C12 lactam, C4-C18 linear aliphatic dicarboxylic acid, polyetherdiamine, and diethylenetriamine (DETA), in which the lactam is 80 to 95 parts by weight, and the linear aliphatic dicarboxylic acid is 1 to 4 parts by weight, and the polyetherdiamine is 4 to 16 parts by weight, and the diethylenetriamine is 0.2 to 0.6 parts by weight.

Abstract: A nylon composite fiber and a nylon fabric thereof are provided. This nylon composite fiber is a dual-component fiber, and contains a long chain polyamide and a polyether modified polyamide polyamide. One monomer of the long chain polyamide contains a long aliphatic chain. One monomer of the polyether modified polyamide contains a polyether chain.

Abstract: A high-power base station and a low-power base station for use in a heterogeneous network system and transmission methods thereof are provided. Interference caused by the high-power base station in control channels of the heterogeneous network system are avoided effectively based on one of the following strategies: (1) transmitting control information of the low-power base station by the high-power base station in the same control channel; (2) transmitting control information of the low-power base station by the low-power base station attached with a user end in a specific control channel which is pre-defined by the low-power base station; and (3) transmitting control information of the low-power base station by the low-power base station in a specific control channel which is determined based on an offset allocated by the heterogeneous network system.