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Your search keyword '"Zhao, Qiaorong"' showing total 14 results
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14 results on '"Zhao, Qiaorong"'

8. N-doped porous carbon decorated with Fe2O3 via catalyzing polysulfide for high-performance lithium-sulfur batteries.

Author

Zhao, Qiaorong, Yang, Sen, Wang, Hui, Zhang, Hongwei, and Qiao, Xun

Abstract

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]

Published
2023
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9. Assessment on seismic performance of circular concrete-filled thin-walled steel tube columns.

Author

Wang, Xuanding, Gao, Pan, Liu, Jiepeng, Zhao, Qiaorong, Xu, Huimin, Wei, Wei, and Wang, Xian-Tie

Subjects
CONCRETE-filled tubes, COMPOSITE columns, STEEL tubes, LATERAL loads, CYCLIC loads, IRON & steel plates, STEEL fracture
Abstract

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]

Published
2023
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10. Friction stir processing of hybridized AZ31B magnesium alloy-based composites by adding CeO2and ZrO2powders: mechanical, wear, and corrosion behaviors

Author

Liu, Shoufa, Paidar, Moslem, Oladimeji Ojo, Olatunji, Poková, Michaela Šlapáková, Mehrez, Sadok, Zain, Azlan Mohd, Zhao, Qiaorong, and Wang, Jinpeng

Abstract

To improve the properties of AZ31B Mg alloy and for the first time, the rare earth cerium oxide (CeO2) and zirconium dioxide (ZrO2) were combined for synergistic benefits and introduced into the structural AZ31B magnesium alloy through the solid-state friction stir processing procedure to form the hybridized AZ31B Mg/ZrO2+CeO2composites under variable levels of the tool's rotational speed up to 1200 rpm. The macro-/microstructure, hardness, shear punching strength, tensile strength, corrosion behaviours, and tribological characteristics such as weight/wear loss, wear rate, coefficient of friction, worn surfaces, and debris of the AZ31B Mg/ZrO2+CeO2hybrid composites were investigated and compared. The results indicated that void, tunnel defect, and ZrO2+CeO2agglomeration could not be prevented at low speed (800 rpm) while defect-free composites were obtained at high speed (1200 rpm). Grain refinement from 7.39 μm to 3.38 μm and the ZrO2+CeO2fragmentation (4.52–2.49 μm) ensued after a rise in the tool's rotational speed owing to higher plastic straining, dynamic recrystallization, and ZrO2+CeO2particle-aided pinning effects. Improvements in hardness (99–135 HV), shear punching strength (121–237 MPa), tensile strength (172–228 MPa) and wear properties of the composite were attained due to the defect elimination, inherent finer Mg grains, and the uniformly dispersed ZrO2+CeO2particles. These attributes also enhanced the corrosion resistance of the AZ31B Mg/ZrO2+CeO2composite at the elevated rotating speed of the tool. The combination of the CeO2and ZrO2particles is an effective particle-blend for improving the properties of Mg alloy to expand its application scope.

Published
2023
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11. Effect of excitation frequency on nonlinear vibration of crack fault in multi-stage gear transmission system

Author

Zhang, Hongwei, Wang, Xin, Zhao, Qiaorong, Li, Taotao, Zhang, Hongwei, Wang, Xin, Zhao, Qiaorong, and Li, Taotao

Abstract

In a multi-stage gear transmission system, the motion state of the system will change with the excitation frequency, and the frequency characteristics will also change accordingly. If this change is not taken into account, there is often a great deviation in identifying and judging system faults according to unified standards, especially when the system has such early undetectable fault as crack. In this paper, the dimensionless differential equations of motion of multistage gear transmission system are established. The stiffness model of gear tooth crack is established by potential energy method. The changes of the motion state of the system with the increase of excitation frequency are obtained by calculating the displacement bifurcation diagram of cracked gear tooth. The influences of crack fault on each motion state are studied by using time domain, frequency domain, phase diagram and Poincaré cross section, and the fault frequency characteristics are summarized. By comparing the theoretical and experimental data of the vibration response characteristics of the system, the motion state of the system can be effectively determined and the crack fault can be identified.

Published
2021

13. Analysis of coupling fault correlation and nonlinear vibration of multi-stage gear transmission system

Author

Zhao, Qiaorong, Wang, Xin, Li, Taotao, Zhang, Hongwei, Zhao, Qiaorong, Wang, Xin, Li, Taotao, and Zhang, Hongwei

Abstract

In the multistage gear transmission system, when multiple faults are coupled, the faults with weak signals are often hidden and hard to identify. Multi-fault coupling may also cause new coupling fault characteristics, such as new peaks or side bands in the spectrum. These characteristics are likely to contain fault information. Studying the sources of frequency components in coupled fault signals will help to decouple the signals and dig out the correlation characteristics between faults. The coupling fault of fixed-axis gear crack and planetary gear tooth broken was studied in this paper. The nonlinear dynamic model of the multi-stage gear transmission system was used for simulation, and the fault frequency characteristics of the system varying with the excitation frequency were obtained. The short-time Fourier transform (STFT) and waterfall plot analysis were applied to the experimental signals to separate the fault features. By comparing the theoretical and experimental signals, we found the natural frequency of the system, the side frequency characteristics of single fault and coupling fault, and the cause of new peaks. This study has a guiding significance for the separation and identification of coupling faults of the multi-stage gear transmission system.

Published
2020

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