Low-frequency broadband multilayer microwave metamaterial absorber based on resistive frequency selective surfaces.

Herein, a low-frequency broadband multilayer metamaterial absorber (MMA) based on resistive frequency selective surfaces (RFSSs) is proposed, which consists of a three-layer RFSS, three-layer polymethacrylimide (PMI) foam substrates, and a copper film. The proposed absorber has the advantages of ultra-broadband absorption with absorptivity more than 90% ranging from 1.91 to 20.78 GHz, which covers the entire S, C, X, and Ku bands with the thickness of 0.102λ L (where λ L corresponds to the wavelength of the lowest operating frequency). The absorption performance can keep good stability in a wide angular range for both TE and TM modes. Moreover, a prototype of the proposed MMA is fabricated and experimentally measured to demonstrate its excellent performance. The experimental results show excellent consistency with numerical simulations.

[The key issues and corresponding strategy of acupoint medicated catgut embedding therapy].

Acupoint medicated catgut embedding therapy is a new type of acupuncture combined with medicine，which has great potential in the prevention and treatment of chronic diseases. This paper describes the clinical application of acupoint medicated catgut embedding in the treatment of common disease, medicated thread productionmethods and acupoints selection.To analyze the problems of the unclear mechanism, the lack of standardization of medicated thread production, the lag of the embedding tool, and the unclear adverse reaction. It is expected to promote the further development of acupoint medicated catgut embedding therapy by strengthening the mechanism of action, optimizing medicated catgut thread, rational design experiments, standardizing medicated thread production, innovating embedding tools, rational formulation, and optimizing acupoint selection.