Few-layer bismuthene is an emerging two-dimensional material in the fields of physics, chemistry, and material science. However, its nonlinear optical property and the related photonics device have been seldom studied so far. Here, we demonstrate a sub-200 fs soliton mode-locked erbium-doped fiber laser (EDFL) using a microfiber-based bismuthene saturable absorber for the first time, to the best of our knowledge. The bismuthene nanosheets are synthesized by the sonochemical exfoliation method and transferred onto the taper region of a microfiber by the optical deposition method. Stable soliton pulses centered at 1561 nm with the shortest pulse duration of about 193 fs were obtained. Our findings unambiguously imply that apart from its fantastic electric and thermal properties, few-layer bismuthene may also possess attractive optoelectronic properties for nonlinear photonics, such as mode-lockers, Q-switchers, optical modulators and so on.

The extended LEPS constructed by 5-MP (the 5-parameter Morse potential) is performed. At low coverage, O2 prefers to dissociate on the Pd(100) and (110) surfaces; however, at high coverage, it can stably adsorb in the H−B−H site on the Pd(111) surface and more molecular states are found. The calculation results agree well with the experimental results, especially, the results of O2 on Pd(111) explain well the three precursor states (the superoxo-like state, the peroxo-like and second peroxo-like state) of HREELS and EELS results. Simultaneously, the conceptions of the molecular dissociation limit and the surface dissociation distance are brought forward first, which illuminate the dissociation mechanism of the O2 on the low-index surfaces and offer the answer to the question why is it more difficult for O2 to dissociate on the (111) surface than on the (100) and (110) surfaces?

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Although microarc oxidation is frequently used in producing wear‐ and corrosion‐resistant coatings on Ti and Ti alloys for biomedical applications, the formation of nonuniform microstructure of the coatings is still unavoidable. To overcome this drawback, this work adopts ultrasonic assistance in the microarc oxidation of Ti–6Al–4V and systematically investigates the influences of ultrasonic treatment with different durations on the coating microstructures and resultant properties. The positive effects of ultrasonic, such as cavitation effect, sound flow effect, and mechanical effect, accelerate the cooling rate of electrolyte and promote the homogeneity of the solute on the sample surface. Therefore, the ultrasonic‐assisted coatings exhibit uniform microstructures with fewer cracks and therefore improve performances. For instance, compared with the counterpart without ultrasonic assistance, the ultrasonic‐assisted coating with 15 min duration demonstrates 25.1% lower mass loss in the tribology test and half corrosion density in Hank's solution. Such results indicate that ultrasonic assistance in microarc oxidation of Ti–6Al–4V can homogenize the microstructures of coatings and enhance their corrosion resistance and wear resistance in human body.

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