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[en] One-dimensional semiconductor nanostructures have demonstrated significant advantages for electrochemical electrode due to their remarkable size-dependent and structure-related properties. In this work, large-scale single-crystalline SnO₂ nanowires have been successfully synthesized by thermal evaporation of a SnO₂ and C powder under atmospheric conditions without any carrier gas or noble metal catalysts-coated substrate. The as-prepared samples exhibit uniform morphology with a thin diameter of 100–200 nm and length up to several tens of micrometers. The SnO₂ nanowires directly grown on the initially deposition layer are found to grow along [301] direction, which is possibly dominated by a vapor–solid (VS) mechanism. The SnO₂ nanowires synthesized by this simple and cheap method deliver a very high lithium storage capacity with good cycle stability and high rate capability, allowing for the achievement of high energy density and long cycle life for the next-generation energy conversion and storage devices. - Highlights: • Large-scale SnO₂ nanowires were prepared by thermal evaporation without any carrier gas or noble metal catalysts. • A growth model based on vapor–solid (VS) mechanism is constructed for the formation of the 1D nanostructure. • SnO₂ nanowires delivered high lithium storage capacity with good cycle stability and high rate capability

No abstract available

[en] Tin dioxide (SnO₂) samples were prepared by direct current electrodeposition method and their electrochemical properties as anode materials for Li-ion battery were investigated with Li as counter electrode. The as-prepared SnO₂ powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and N₂-adsorption-desorption experiments. It was found that SnO₂ can be synthesized by one-step electrodeposition and the crystallinity improved markedly after annealed. The samples consisted of uniform spherical SnO₂ crystal particles with size in the order of 100∼200nm. After dried at 120 deg. C and annealed at 400 deg. C, 600 deg. C, 800 deg. C respectively, the samples were used as anode materials for Li-ion battery. The results showed that the samples annealed at 600 deg. C had a high coulombic efficiency and had the best electrochemical performance.

[en] A biodegradable Ca-deficient hydroxyapatite (Ca-def HA) coating has been directly prepared on Mg–Zn–Ca alloy by pulse electrodeposition to improve its corrosion resistance and biocompatibility. However, the formation mechanism of such a Ca-def HA coating on magnesium substrate is still not clear. In this study, the microstructure evolution of the coating was characterized using x-ray diffractometer, x-ray photoelectron spectroscopy and scanning electron microscopy. Thermodynamic and kinetic studies of the precipitation of hydroxyapatite (HA), octacalcium phosphate (OCP) and dicalcium phosphate dihydrate (DCPD) in the used electrolyte were also carried out. Theoretical analyses illustrate that the precipitation of HA, OCP and DCPD are all possible when the electrolyte pH is higher than 6 at 80 °C, and that the higher the pH value, the more favorable is the formation of HA. Nevertheless, there is mainly poor crystalline Ca-def HA on the substrate when pulse electrodeposition lasts for 5 min, and its crystallinity increases with duration time The direct formation of the Ca-def HA coating on Mg–Zn–Ca alloy is closely dependent on the phase composition and microstructure of the substrate, the deposition parameters and Mg²⁺ ions substitution in HA structure.

[en] Highlights: • A statistical analysis of 1207 marine accidents worldwide from 2010 to 2019. • A critical literature review on previous studies on marine accident severity. • A study on the relationship between the influencing factors and accident severity. • Provision of recommendations for the improvement of maritime safety. This study aims to explore the relationship between the severity of marine accidents and influencing factors. An ordered logistic regression model is used to reflect the relationship between these factors and the severity of marine accidents using the worldwide accident investigation reports in the period of 2010–2019. The obtained results show that the marine accident severity is positively associated with sinking accidents, far away from port, strong wind, heavy sea, strong current and/or good visibility. With respect to ship types, fishing vessels, yachts and sailing vessels, and other ship types are the ship types most involved in accidents of higher severity. The severity level is higher for ships having incomplete or invalid seafarers’ certificates, inadequate ship manning, incomplete or invalid ship certificates and/or over 30 years of age. Seafarers with poor theoretical knowledge and less sea experience are more likely to be involved in accidents of serious consequences. Small water depth and ship types such as chemical tankers, oil tankers, container ships and/or bulk carriers are negatively related to the accident severity. The results of this study can be used to assist the relevant maritime authorities in taking effective measures of preventing the occurrence of serious marine accidents.

[en] ZnO nanoparticle aggregations with porous morphology were prepared by the direct precipitation of Zn(OH)₂ coats on the surface of Zn powders, and succedent calcination of Zn/Zn(OH)₂ composites. The coating and calcination reaction mechanism was given to explain the formation of the novel structure. The samples were characterized by X-ray diffraction, energy-disperse X-ray spectrometry, scanning electron microscopy and ultraviolet-visible spectrometry. It was found that ZnO nanoparticle aggregations were irregular porous microspheres consisting of ZnO nanoparticles with hexagonal wurtzite structure, and the diameters of bores in the microspheres ranged from tens to hundreds nanometers. The gas sensing properties of the samples were investigated. Sensors based on the samples showed high sensitivity and short response time to the H₂S gas. These characteristics make the sensors to be excellent potential candidates for detecting H₂S. The electrochemical performance of samples as anode materials for Li-ion battery was also investigated.