Qing Yang Steve WuNan ZhangVincent LimLei Zhang...
470-480页
查看更多>>摘要：Terahertz(THz)computed tomography(THz CT)exhibits the potential to provide a wealth of data,surpassing that of THz tomographic imaging in applications such as detecting embedded defects,particularly defect evolution within a glass fiber-reinforced polymer.To realize high-resolution THz CT,a systematic approach guided by wave propagation simulation was employed.First,the front wave of the THz beam was fine-tuned to realize a beam diameter of＜2 mm.To mitigate the strong refractive effect and minimize Fresnel reflection loss,a refractive-index-matching material was fabricated and utilized as a rounded enclosure for samples with sharp corners.To further improve the reconstruction resolution,a flat surface enclosure was applied to collect all incident beams at the detector.To realize comparable results to those of full-angle CT,a limited-angle CT approach was implemented,and the frequency range 0.1-3 THz was used in the image reconstruction study.The experimental and simulated images were used to validate the findings,and conductive and non-conductive defects measuring 200 μm were successfully visualized.Additionally,a custom-built user interface enabled us to visualize the field spatial distribution of the THz beam with respect to frequency.
查看更多>>摘要：Although Li-S batteries have a high theoretical capacity,their application are significantly hindered by the com-plex shuttle effect of polysulfides.To address the issues,in this paper,Ni2V2O7 prepared by a simple method is proposed as an efficient catalyst for S cathodes.Ni2V2O7 composed of Ni-O octahedra and V-O tetrahedra has a specific electronic structure.The Ni and V atoms interacted,enabling a fast kinetics of polysulfide redox.Moreover,Ni2V2O7 contains metal sites(Ni and V)and oxygen vacancies,providing a high adsorption capacity and abundant active sites for polysulfide redox.Therefore,Li-S batteries consisting of Ni2V2O7-based cathodes exhibit an excellent cycling stability with a capacity of 1061 mAh g-1 and capacity retention of 87.6％after 150 cycles at 0.2 C.Moreover,at 1 C rate,the batteries exhibit a capacity of 706 mAh g-1 after 300 cycles with a minimal capacity decay of only 0.08％per cycle.
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