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In order to improve the wear resistance of 7075 aluminum alloy surface，the hard ceramic coating on the aluminum alloy surface was constructed by micro-arc oxidation technology in the electrolyte solution doped with nano-BN particles.The effects of the addition of nano-BN particles on the arc initiation voltage of the micro-arc oxidation process，surface morphology，porosity，phase composition，thickness，roughness，microhardness and friction and wear properties of coating were investigated by means of scanning electron microscopy (SEM)，energy dispersive spectrometer (EDS)，X-ray diffractometer (XRD)，photoelectron spectrometer (XPS)，roughness tester，microhardness tester，friction and wear testing machine.Results showed that the coatings were mainly composed of α-Al2O3 and γ-Al2O3 phase.Nano-BN particles increased the arc initiation voltage，and increased the thickness，roughness and hardness of coating.When the concentration of nano-BN particles was 0.3 g/L，the overall performance of the as-obtained micro-arc oxidation coating was the best.At this time，the number of micropores in the coating was small，the pore size was small，and the surface density was high.Compared with the coating prepared in the basic electrolyte，the coating’s surface porosity decreased from 6.617%to 3.518%.Meanwhile，the hardness reached the highest value 916.7 HV10 N，the thickness was 20 μm，and the roughness was 2.38 μm.The friction coefficient was reduced to 0.7，and the wear rate decreased to 7.84×10-5 mm3/(N·m).

Renal clearable nanoparticles have been drawing much attention as they can avoid prolonged accumulation in the body by efficiently clearing through the kidneys. While much effort has been made to understand their interactions within the kidneys, it remains unclear whether their transport could be influenced by other organs, such as the liver, which plays a crucial role in metabolizing and eliminating both endogenous and exogenous substances through various biotransformation processes. Here, by utilizing renal clearable IRDye800CW conjugated gold nanocluster (800CW4‐GS18‐Au25) as a model, we found that although 800CW4‐GS18‐Au25 strongly resisted serum‐protein binding and exhibited minimal accumulation in the liver, its surface was still gradually modified by hepatic glutathione‐mediated biotransformation when passing through the liver, resulting in the dissociation of IRDye800CW from Au25 and biotransformation‐generated fingerprint message of 800CW4‐GS18‐Au25 in urine, which allowed us to facilely quantify its urinary biotransformation index (UBI) via urine chromatography analysis. Moreover, we observed the linear correlation between UBI and hepatic glutathione concentration, offering us a noninvasive method for quantitative detection of liver glutathione level through a simple urine test. Our discoveries would broaden the fundamental understanding of in vivo transport of nanoparticles and advance the development of urinary probes for noninvasive biodetection. [ABSTRACT FROM AUTHOR]

Unbalanced body pressure distribution caused by poor sitting posture is a significant factor causing lumbar disease. Research on the dynamic adjustment strategy for comfort sitting posture is of great significance to the prevention and improvement of lumbar disease. In this study, based on the pressure sensor array, the body pressure distribution in different sitting postures are obtained, including: back bow, waist bow, body slip, body right leaning, standard sitting position, and body left leaning. The recognition of the human body posture was achieved using the support vector machine algorithm and the accuracy rate reach to 83.33%. Furthermore, the evaluation indicators for sitting comfort of the human body are proposed using the maximum pressure, average pressure, maximum pressure gradient, average pressure gradient and asymmetry coefficient, the accuracy of the above indicators were verified using semantic differential subjective evaluation method. Experimental results show that there is a strong positive correlation between objective indicators and seat comfort. In addition, the dynamic adjustment strategy using airbag base on seat comfort evaluation is studied.

In this study, molecular dynamics (MD) simulation is adopted to explore the mechanical properties and microstructure evolution of a dual-phase CoCrFeMnNi high-entropy alloy during nanoindentation. The influence of the volume fraction of the hexagonal closed-packed (hcp) phase is considered, and the P–h curves are plotted, where the indentation depths of curves initially into the plastic stage and the maximum indentation force for each curve are significantly different. At the elastic stage, the results from MD simulations are in agreement with those of the Hertz contact theory. However, the fitting coefficient k is remarkably influenced by the hcp phase volume fraction. The correlating P–h curves of plastic deformation are investigated by analyzing the instantaneous defect structures dominated by the nucleation of Shockley partial dislocations or the movements of stacking faults. Furthermore, the microstructure evolution with the increment in indentation depth is demonstrated, and it revealed that the plastic deformation is affected by the phase structure indenter that initially contacts. Unlike the slipping process for the face-centered-cube phase, a new hcp structure grain is created through dynamic recrystallization if the hcp phase is the first phase that the indenter touches. [ABSTRACT FROM AUTHOR]

Considering the impact of chemical compositions, the mechanical properties and microstructure evolution of the single-crystal FCC CoCrFeNi-based high-entropy alloys (HEAs) are investigated by using molecular dynamics simulation in nanoindentation. The addition of Cu and Mn elements would decrease the stacking faults energy resulting in the dislocation-mediated deformation. Moreover, the total number of chemical compositions of CoCrFeNi-based HEAs has critical effects on the results according to the Hertz contact theory. The plastic deformation is studied by correlating the P–h curve with the instantaneous defect structure and dominated by nucleation of Shockley partial dislocations or the motions of stacking faults. Owing to the large amount of Hirth and Stair-rod dislocations, CoCrFeNiCu HEA has the largest indentation force, next followed by CoCrFeNi and CoCrFeNiMn HEAs. Then, the influence of chemical composition on the radial distribution function is explored, and it exhibits that Cu and Mn elements are conducive to amorphization. Finally, the analysis of microstructure evolution reveals that the Mn addition would contribute to the slipping process for CoCrFeNi-based HEAs causing the decrease of indentation force and hardness. In contrast, the Cu addition results in irregular slipping mode accompanying the appearance of dislocation loops. In this simulation, the mechanical properties of single-crystal CoCrFeNi-based HEAs are strongly dependent on the chemical composition, which contributes to the composition design of high entropy alloys in the future. [ABSTRACT FROM AUTHOR]

Complex salt solution systems are commonly used as electrolytes for microarc oxidation (MAO). To investigate the MAO phenomenon in simple electrolytes and evaluate the efficacy of MAO coatings, an Na3PO4 monosalt solution was used as the MAO electrolyte. In this study, the effects of the voltage and Na3PO4 concentration on the spark discharge phenomenon, thickness, roughness, and corrosion resistance of the coatings were investigated. The results showed that MAO coatings were effectively synthesised at high concentrations and voltages. Furthermore, the addition of KOH to the Na3PO4 monosalt solution resulted in discernible spark discharge and improved the corrosion resistance of the coatings. Thus, an MAO coating can be efficiently prepared using Na3PO4 solution as the electrolyte. In addition, the addition of KOH to the Na3PO4 monosalt solution reduced the voltage required for coating formation and enhanced the corrosion resistance of the coating. [ABSTRACT FROM AUTHOR]