2021, Lu, Q., Jie, Y., Meng, X., Omar, A., Mikhailova, D., Cao, R., Jiao, S., Lu, Y., Xu, Y.

Lithium (Li) metal is regarded as the ultimate anode for next-generation Li-ion batteries due to its highest specific capacity and lowest electrochemical potential. However, the Li metal anode has limitations, including virtually infinite volume change, nonuniform Li deposition, and an unstable electrode–electrolyte interface, which lead to rapid capacity degradation and poor cycling stability, significantly hindering its practical application. To address these issues, intensive efforts have been devoted toward accommodating and guiding Li deposition as well as stabilizing the interface using various carbon materials, which have demonstrated excellent effectiveness, benefiting from their vast variety and excellent tunability of the structure–property relationship. This review is intended as a guide through the fundamental challenges of Li metal anodes to the corresponding solutions utilizing carbon materials. The specific functionalities and mechanisms of carbon materials for stabilizing Li metal anodes in these solutions are discussed in detail. Apart from the stabilization of the Li metal anode in liquid electrolytes, attention has also been paid to the review of anode-free Li metal batteries and solid-state batteries enabled by strategies based on carbon materials. Furthermore, we have reviewed the unresolved challenges and presented our outlook on the implementation of carbon materials for stabilizing Li metal anodes in practical applications.

2019, Xu, Y., Birnbaum, P., Pilz, S., Zhuang, X., Zhao, Z., Kräusel, V.

In order to analyze the softening behavior of 22MnB5 steel and further predict the constitutive relationship during hot sheet metal forming, a series of isothermal hot compression tests were conducted at the temperature range of 800–950 °C and strain rate range of 0.01–0.8 s−1 on BAEHR 805 A/D thermo-mechanical simulator system. Based on the friction corrected flow curves, the characteristic strain and stress of dynamic recrystallization (DRX) were derived from the Kocks-Mecking plots and expressed as a function of Zener-Hollomon parameter. Moreover, a physical constitutive model considering work hardening (WH), dynamic recovery (DRV) and DRX as well as corresponding JMAK-type DRX kinetics were developed. The results showed that the established physical equations can accurately predict the flow behavior with a correlation coefficient of 0.997 and average absolute relative error of 3.89%. Optical observation of the microstructure after hot compression revealed that the established DRX kinetics accurately reflects the reality, and then a Zener-Hollomon parameter dependent dynamic recrystallized grain size model was developed. Furthermore, EBSD analysis was carried out to study the effect of deformation conditions on martensite morphology and the results show that a lower temperature and higher strain rate lead to a finer martensite packet while the martensite block width becomes larger under the higher strain rate.

2017, Wu, J., Xu, Y., Ma, J.

As the fluctuations of the internal bioelectricity of nervous system is various and complex, the external electromagnetic radiation induced by magnet flux on membrane can be described by the non-Gaussian type distribution of Levy noise. Thus, the electrical activities in an improved Hindmarsh-Rose model excited by the external electromagnetic radiation of Levy noise are investigated and some interesting modes of the electrical activities are exhibited. The external electromagnetic radiation of Levy noise leads to the mode transition of the electrical activities and spatial phase, such as from the rest state to the firing state, from the spiking state to the spiking state with more spikes, and from the spiking state to the bursting state. Then the time points of the firing state versus Levy noise intensity are depicted. The increasing of Levy noise intensity heightens the neuron firing. Also the stationary probability distribution functions of the membrane potential of the neuron induced by the external electromagnetic radiation of Levy noise with different intensity, stability index and skewness papremeters are analyzed. Moreover, through the positive largest Lyapunov exponent, the parameter regions of chaotic electrical mode of the neuron induced by the external electromagnetic radiation of Levy noise distribution are detected.

2012, Kovaleva, N.N., Kugel, K.I., Bazhenov, A.V., Fursova, T.N., Löser, W., Xu, Y., Behr, G., Kusmartsev, F.V.

Magnetic materials are usually divided into two classes: those with localised magnetic moments, and those with itinerant charge carriers. We present a comprehensive experimental (spectroscopic ellipsomerty) and theoretical study to demonstrate that these two types of magnetism do not only coexist but complement each other in the Kondo-lattice metal, Tb2PdSi3. In this material the itinerant charge carriers interact with large localised magnetic moments of Tb(4f) states, forming complex magnetic lattices at low temperatures, which we associate with self-organisation of magnetic clusters. The formation of magnetic clusters results in low-energy optical spectral weight shifts, which correspond to opening of the pseudogap in the conduction band of the itinerant charge carriers and development of the low- and high-spin intersite electronic transitions. This phenomenon, driven by self-trapping of electrons by magnetic fluctuations, could be common in correlated metals, including besides Kondo-lattice metals, Fe-based and cuprate superconductors.

2016, Xu, Y., Li, Y., Zhang, H., Li, X., Kurths, J.