In this work, thermal stability of an in situ exsolved Ni–Fe nanoparticle structured Sr2Fe1.4Ni0.1Mo0.5O6 (SFMNi) perovskite type hydrogen electrode is studied by examining the evolution of electrode polarization resistance and material morphology. During the 745-h durability testing, the polarization resistance measured at 800 °C dramatically decreases from 0.68 to 0.31 Ω cm2 with an activation rate of 22.92%/100 h in the initial 200 h, then undergoes a stable period in the following 200 h, and subsequently rises to 0.40 Ω cm2 with a degradation rate of 6.20%/100 h in the last 345 h. Variation of electrode electrochemical performance could be explained by the morphology evolution of the exsolved nanoparticles, which are well-fitted by the self-limiting growth model. Distribution of relaxation time analysis results indicate that gas conversion is the primary rate-limiting step during the electrode reaction and can be effectively accelerated by the gradually exsolved Ni–Fe nanoparticles during the durability testing. Additionally, higher temperature results in a shorter equilibrium time, which can be explained by the accelerated thermodynamic and kinetic properties of the in situ exsolution process because of the lowered Gibbs free energy at higher temperature. The approach developed in this study could be used to predict the lifetime of the in situ metallic nanoparticle structured electrode and provide a significant insight into the development of other ceramic materials with high activity and robust stability for solid oxide cell application.

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A novel method for simultaneously measuring six degree-of-freedom (6DOF) geometric motion errors is proposed in this paper, and the corresponding measurement instrument is developed. Simultaneous measurement of 6DOF geometric motion errors using a polarization maintaining fiber-coupled dual-frequency laser is accomplished for the first time to the best of the authors' knowledge. Dual-frequency laser beams that are orthogonally linear polarized were adopted as the measuring datum. Positioning error measurement was achieved by heterodyne interferometry, and other 5DOF geometric motion errors were obtained by fiber collimation measurement. A series of experiments was performed to verify the effectiveness of the developed instrument. The experimental results showed that the stability and accuracy of the positioning error measurement are 31.1 nm and 0.5 μm, respectively. For the straightness error measurements, the stability and resolution are 60 and 40 nm, respectively, and the maximum deviation of repeatability is ± 0.15 μm in the x direction and ± 0.1 μm in the y direction. For pitch and yaw measurements, the stabilities are 0.03″ and 0.04″, the maximum deviations of repeatability are ± 0.18″ and ± 0.24″, and the accuracies are 0.4″ and 0.35″, respectively. The stability and resolution of roll measurement are 0.29″ and 0.2″, respectively, and the accuracy is 0.6″.

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The rotary axis is the basis for rotational motion. Its motion errors have critical effects on the accuracy of the related equipment, such as a five-axis computer numerical control machine tool. There are several difficult problems in the implementation of high-precision and fast measurement of the multi-degree-of-freedom motion errors of a rotary axis. In this paper, a novel method for the simultaneous measurement of five-degree-of-freedom motion errors of a rotary axis is proposed, which uses a single-mode fiber-coupled laser with a full-circle measuring range. It has the advantages of high efficiency, low cost, and it requires no decoupling calculation. An experimental system was built and a series of experiments were performed. The standard deviation of stability for 60 min of the five-degree-of-freedom measurement is 0.05 arcsec, 0.06 arcsec, 0.04 μm, 0.03 μm, and 0.19 arcsec, respectively. The repeatability deviation of measuring an indexing table is ± 3.4 arcsec, ± 4.6 arcsec, ± 2.6 μm, ± 2.4 μm, and ± 3.2 arcsec. The maximum deviation of comparison is 3.9 arcsec and 3.2 arcsec. These results demonstrate the effectiveness of the proposed method; thus, a new approach of simultaneous measurement of the multi-degree-of-freedom motion errors of a rotary axis is provided.

Herein, the redox-reversible stability of a perovskite type SFMNi cathode decorated with in situ exsolved Ni–Fe alloy nanoparticles is investigated using experimental results and explained by the exsolution–redissolution model.

A measurement system to simultaneously measure six degree-of-freedom (6DOF) geometric errors is proposed. The measurement method is based on a combination of mono-frequency laser interferometry and laser fiber collimation. A simpler and more integrated optical configuration is designed. To compensate for the measurement errors introduced by error crosstalk, element fabrication error, laser beam drift, and nonparallelism of two measurement beam, a unified measurement model, which can improve the measurement accuracy, is deduced and established using the ray-tracing method. A numerical simulation using the optical design software Zemax is conducted, and the results verify the correctness of the model. Several experiments are performed to demonstrate the feasibility and effectiveness of the proposed system and measurement model.

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