Study on Ce and Y co-doped BaFeO3-δ cubic perovskite as free-cobalt cathode for proton-conducting solid oxide fuel cells

The use of triple-conducting (electron, proton, oxide ion) cathodes is an effective strategy for significantly decreasing cathode polarization of proton-conducting SOFCs. In this study, a new triple-conducting BaFe_0.8Ce_0.1Y_0.1O_3-δ (BFCY) perovskite cathode is prepared by Pechini sol-gel process and its properties are evaluated comprehensively. High-temperature XRD measurement demonstrates that the codoping of Ce and Y can stabilize the cubic perovskite of BFCY in investigated temperature range from room temperature to 900 °C. BFCY material exhibits a moderate average thermal expansion coefficient of 22.08 × 10^?6 K^?1 smaller than cobalt-based cathode and good chemical compatibility with BaZr_0.1Ce_0.7Y_0.2O_3-δ (BZCY) electrolyte after the calcining treatment at 1000 °C. XPS analysis indicates the existence of Ce^3+/4+ and Fe^3+/4+ ions and abundant oxygen vacancies in BFCY powder surface. Thermal gravimetric analysis reveals that a larger number of oxygen deficiencies -are generated at elevated temperatures, which favors the catalytic activity on oxygen reduction. The maximum value of BFCY electrical conductivity remains at 1.55 S cm^?1 at 600 °C in humidified air. BCFY (BaCe_0.8Fe_0.1Y_0.1O_3-δ) material is introduced in order to construct BFCY-BCFY composite cathode with the good cathode/electrolyte interface adhesion. For the single cell with BFCY-BCFY composite cathode, the polarization resistance as low as 0.05 Ω cm² and peak power density as high as 750 mW cm^?2 are reached at 700 °C, respectively, demonstrating the great potential of BFCY oxides as proton-conducting SOFC cathode.     

The research of superheated steam temperature control based on generalized predictive control algorithm and adaptive forgetting factor

The superheated steam temperature system of the thermal power plant has the characteristics of large inertia, nonlinearity, and strong time variation, which make it difficult to be controlled. To address these problems, this paper proposes a generalized predictive control algorithm with an adaptive forgetting factor. First, based on a fuzzy algorithm and a recursive least squares algorithm, the controlled object's model can be quickly and accurately obtained with the adaptive forgetting factor in real time. It overcomes the nonlinear and time-varying problems of the controlled object in the control progress. Meanwhile, it also solves the problem of data saturation and the weight assignment of the “new and old” data during online identification. Second, an adaptive generalized predictive controller algorithm has been developed with the controlled object. It solves the large inertia problem of the controlled object. Finally, through establishing simulation model of the superheated steam temperature system and simulating, the results show that the proposed method has better control performance, antidisturbance ability, adaptability, and robustness. Moreover, it has a certain reference significance for the design of a practical control system.     

Simulation of the Q2 loess slope with seepage fissure failure and seismic response via discrete element method

Bulletin of Engineering Geology and the Environment - The Loess Plateau has a history of frequent landslides. Considering the Xiangning landslide that occurred on March 15, 2019, in Shanxi...     

Correction to: Rooted Spanning Superpixels

International Journal of Computer Vision - The author regrets the omission of the following additional references to the International Journal of Computer Vision article, “Rooted Spanning...     

A novel framework for UAV returning based on FPGA

The Journal of Supercomputing - To date, most unmanned aerial vehicle (UAV) returning technology has relied on the global positioning system (GPS). The risk is that the UAV may be spoofed by fake...     

Improvement on a privacy-preserving outsourced classification protocol over encrypted data

Wireless Networks - In outsourced classification services, classifier owners outsource their classifiers to remote servers due to resource constraints, and users can request classification services...     

圆锥破碎机生产能力优化研究

圆锥破碎机等破碎机械设备已经得到了化工、建筑以及冶金等诸多行业的广泛应用,为了确保破碎机生产能力能够满足生产作业的要求,在分析其工作原理的基础上,对其生产能力优化措施进行详细分析.根据研究结果可知,相较于优化前,圆锥破碎机的生产率得到了显著提升,有助于提高其生产效率和质量.     

Biomimetic Strain-Stiffening Hydrogel with Crimped Structure

Synthetic hydrogels are unique tissue mimics but rarely reproduce the strain-stiffening properties of native tissues. This mechanical mismatch impairs the performance of hydrogels in practical applications. Inspired by the crimped structure of collagenous tissues, a series of strain-stiffening hydrogels composed of curved parallel fibers are developed. These fibers are constructed from a bundle of intertwisted nanofibrils composed of short alkyl side chain-modified polymer chains. This hierarchical organization enables exquisitely cascaded deformation that facilitates soft-to-firm and resilience-to-viscoelasticity transitions, thus synergically mimicking the strain-adaptive stiffening and damping behaviors of natural tissues. Together with structural evolution and a constitutive model, rationally tuning the tortuosity and flexibility of the curved fibers produces a diverse combination of strain-stiffening properties and unprecedented penetration into the regions of several tissues. The crimped structure and the resultant stiffening properties constitute major improvements to nanofiber-based scaffolds for use in collagenous tissue repair.