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Limited due to the severe shuttle effect, the wide application of lithium-sulfur batteries is difficult to achieve. To overcome this problem, various materials with catalytic effect are developed to inhibit the polysulfide shuttle effect. Herein, we synthesized N-doped porous carbon/Fe2O3 composite (NPC/FO)–efficient catalysts to promote the polysulfide conversion during the electrochemical cycles. Owing to the superior catalytic effect of NPC/FO composite host, the polysulfide shuttle effect could be inhibited. As a result, the as-prepared NPC/FO@S cathode delivered initial high capacity of 1288 mAh/g at 0.1 C. In addition, the NPC/FO@S cathode exhibits excellent rate performance and stable cycling performance. Our finding demonstrates that the N-doped porous carbon/Fe2O3 composites are new efficient host materials for lithium-sulfur batteries. [ABSTRACT FROM AUTHOR]

Concrete-filled steel tubular (CFST) with circular section is a very efficient composite component bearing vertical loads, which takes advantage of the synergy of steel tube and concrete to fully develop the strengths of both materials. To promote the application of circular CFST columns in multi-story buildings or medium-span bridge piers with improved economic efficiency, circular CFSTs using thin-walled steel tubes were studied in this paper. 8 specimens were designed and tested to assess their seismic performance under constant axial compression and cyclic lateral loads. The key test parameters include axial compression ratio, diameter-to-thickness ratio of steel tube, as well as stiffening scheme. The effectiveness of two steel plate stiffeners (longitudinal stiffener, binding stiffener) at the potential plastic hinges of thin-walled circular CFST columns was verified and discussed. Although all specimens failed in a manner characterized by significant local buckling of steel tubes, they still performed a relatively ductile behavior with the ductility coefficients generally exceeding 4.0, and the ultimate drift ratios exceeding 1/40. The steel plate stiffeners did not achieve the expected enhancement in strength and ductility, due to the premature fracture in the steel tube which may be caused by the damage in the welding heat-affected zone. Based on the test results, a numerical model and a simplified hysteretic model were established to predict the seismic responses of the thin-walled circular CFST columns. [ABSTRACT FROM AUTHOR]