查看更多>>摘要：? 2022 Acta Materialia Inc.A novel temperature-dependent electrochemical system has been designed for in-operando time-resolved X-ray diffraction (XRD) study with laboratory X-ray sources. Meanwhile, a dedicated in-situ XRD battery cell has been designed for the in-situ XRD characterization of standard coin cell batteries. Thanks to a shaped Be window, the detection-angle of this in-operando system covers a wide range from 4° to 160° XRD patterns can be collected over the wide temperature range, -30 °C to 100 °C. To test the device, LiMn2O4 and LiFePO4 electrode materials are measured and in-operando XRD data are collected in electrochemical processes at low and high temperatures. This in-operando system enables original in-operando investigations on the electrode structural evolution of batteries vs. temperature, allowing a deeper understanding of the structural evolution of electrode materials.
查看更多>>摘要：? 2022Utilization of optical limiting materials to suppress the input intense laser energy is obligatory in a wide variety of applications that deploy the high?power laser sources. In this letter, we demonstrate that the optimization of borate structural units in lanthanum borate (LB) glasses through the addition of various concentrations of heavy metal oxides (HMOs) (PbO and Bi2O3) resulting in achievement of an optimum optical threshold value. The structural changes of these glasses were analyzed by 11B MAS?NMR and Raman spectroscopic techniques. Nonlinear optical attributes were assessed by the Z?scan technique. The enhancement of two?photon absorption coefficient and decrement in optical limiting threshold factors suggest the LB glasses containing HMOs could be beneficial for power optical limiting devices. The achieved optical limiting threshold values of 0.075 and 0.114 J/cm2 at 700 and 800 nm, respectively, are superior compared to advanced materials such as nanoparticles, carbon nanotubes, and few?layers of MoS2/Polymethylmethacrylates.
查看更多>>摘要：? 2022 Acta Materialia Inc.EXAFS analysis of pure elements, binary and ternary equiatomic refractory alloys within the Nb-Zr-Ti-Hf-Ta system is performed at the Nb and Zr K-edges to analyze the evolution of the chemical local environment and the lattice distortion. A good mixing of the elements is found at the atomic scale. For some compounds, a distribution of distances between the central atom and its neighbors suggests a distortion of the structure. Finally, analysis of the Debye-Waller parameters shows some correlation with the lattice distortion parameter δ2, and allows to quantify experimentally the static disorder in medium entropy alloys.
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Elsevier