Search

Xanthine-functionalized molybdenum oxide nanodots (X-MoO3-x NDs) with peroxidase (POD)-like activity were developed for selective, sensitive, and facile colorimetric quantification of xanthine oxidase (XO). Xanthine functionalization can not only be favorable for the successful nanozyme preparation, but also for the specific recognition of XO as well as the simultaneous generation of hydrogen peroxide, which was subsequently transformed into hydroxyl radical to oxidize the chromogenic reagent based on the POD-like catalysis. Under the optimized conditions, the colorimetric biosensing platform was established for XO assay without addition of further substrates, showing good linearity relationship between absorbance difference (ΔA) and XO concentrations in the range 0.05–0.5 U/mL (R2 = 0.998) with a limit of detection (LOD) of 0.019 U/mL. The quantification of XO occurs in 25 min, which is superior to the previously reported and commercial XO assays. The proposed method has been successfully used in the assay of human serum samples, showing its high potential in the field of clinical monitoring. [ABSTRACT FROM AUTHOR]

Compacted graphite iron has been used more and more in industry because of its excellent mechanical properties, especially in the automobile industry to manufacture high performance and light weight diesel engine. However, the excellent mechanical properties of compacted graphite iron cause the tool life greatly shortened. In this research, the influence of tool structure on tool life is studied by simulation and experiment. Firstly, turning simulations for tools with different rake angles, clearance angles, and cutting edge radius were performed by the software Deform. Then orthogonal simulation was used to optimize the tool parameters. In addition, according to the tool parameters obtained in the simulation, a batch of tools with rake angles of 13°, 15°, and 19° were prepared, and their performances in turning compacted graphite cast iron were studied. The experiment results show that the life of the tool with 19° rake angle was 11.73% and 16.94% higher than that of the tool with 13° rake angle and 15° rake angle, respectively. And it has the minimum cutting force and lower wear value of the flank face. Our research is especially aimed at compacted graphite iron, which might have some function in improving the processing efficiency of compacted graphite iron. [ABSTRACT FROM AUTHOR]

Hydrodynamic bearing is becoming an indispensable component of high-accuracy devices such as high-speed machine tools. Recently, the study of textured surface bearing has become one of the highly researched topics. Among the different types of surface texture, partially textured bearing shows outstanding performances on anti-vibration. However, most of the research focuses on the theoretical models of partial texture. In this paper, several bearings with no texture, full texture and partial texture are fabricated for stability and stiffness tests. The result shows that the partially textured bearings with 60% of textured ratio and 4.9% of area ratio exhibit the best properties, which could decrease the maximum amplitude by 45.8% at 9000 rpm. In addition, the textured surface with the optimal textured ratio of 60% can reduce the static stiffness and improve the dynamic stiffness. Therefore, partially textured bearings are particularly significant to the stability enhancement of the bearing system, which can lead to the performance and security improvement of the sliding bearing in high-speed applications. [ABSTRACT FROM AUTHOR]

The design and development of excellent microwave absorption (MA) material is significant for healthcare, electronic, and security industries. Herein, a sophisticated composite with the advantages of large interlayer space, nanoparticles with small size, and hierarchical nanostructure (core@shell@void@shell configuration) simultaneously is demonstrated for the first time. Such unique SiO2@TiO2 nanoparticle was fabricated via a multi-step process. Associating maximum reflection loss value can reach –35.2 dB in certain frequency of 11 GHz and thickness of 3.0 mm. Small-sized TiO2 nanoparticles (about 6 nm) in first coating and large gap between TiO2 coating layers are significantly critical for the superior MA performance. Our work points a new direction to rationally construct high-performance microwave absorber. [ABSTRACT FROM AUTHOR]