Fabrication and Impedance Performance of Gradient LaNi0.6Fe0.4O3-δ-Gd0.2Ce0.8O2 Composite Cathodes for Intermediate Temperature Solid Oxide Fuel Cell

应用丝网印刷和共烧结制备LaNi0.6Fe0.4O3-δ(LNF)-Gd0.2Ce0.8O2(GDC)梯度复合阴极/Gd0.2Ce0.8O2/Sc0.1Zr0.9O1.95(ScSZ)/Gd0.2Ce0.8O2/LaNi0.6Fe0.4O3-δ(LNF)-Gd0.2Ce0.8O2(GDC)，组成梯度复合阴极对称电池. 实验表明，在750 oC工作温度下单层70%LNF-30%GDC（文中均指质量百分比）复合阴极的极化电阻为0.581 Ω·cm2，而三层60%LNF-40%GDC/70%LNF-30%GDC/100%LNF复合阴极的极化电阻最小（0.452 Ω·cm2）. 由于阴极组成在ScSZ电解质和LNF阴极之间呈梯度变化，因此获得了最佳的阴极/电解质界面，大大加快了三相界面或气体/阴极/电解质三相接触点反应区的扩散，其电荷传递电阻Rct和浓差极化电阻Rd均减小，因而具有最低的阴极极化电阻值.A LNF-GDC composite cathode with a gradual change in the composition between ScSZ electrolyte and LNF cathode was fabricated to reduce the cathode polarization resistance (Rp). The gradual change in composition between ScSZ electrolyte and LNF cathode shows the decreases in the charge transfer resistance (Rct) and gas phase diffusion resistance (Rd). The results revealed that the Rp value, measuring 0.452 Ω·cm2 at 750 °C, was the lowest for LNF-GDC composite cathodes with three layers and gradient changes in composition between ScSZ and LNF (Cathode C),, whereas the Rp value of 70%LNF-30%GDC composite cathodes with one layer (Cathode A) was 0.581 Ω·cm2. The reduction in Rp for the LNF-GDC composite cathodes with three layers and gradient changes in composition between ScSZ and LNF may be related to the fact that the microstructure of the cathode/electrolyte interfaces is significantly improved, resulting in the increase in the area of triple phase boundaries (TPBs), which enhanced the surface exchange of oxygen. This implied that the gradient LNF-GDC composite cathodes showed excellent performance in terms of its electrochemical properties.国家自然科学基金项目(No. 51201098)资助作者联系地址：上海交通大学 机械与动力工程学院，燃料电池研究所，上海 200240Author's Address: Institute of Fuel Cell, School of Mechanical Engineering, Shanghai Jiaotong University, Shanghai 200240, China通讯作者E-mail：[email protected]

Measurement of integrated luminosity of data collected at 3.773 GeV by BESIII from 2021 to 2024

We present a measurement of the integrated luminosity e+e- of collision data collected by the BESIII detector at the BEPCII collider at a center-of-mass energy of Ecm = 3.773 GeV. The integrated luminosities of the datasets taken from December 2021 to June 2022, from November 2022 to June 2023, and from October 2023 to February 2024 were determined to be 4.995±0.019 fb-1, 8.157±0.031 fb-1, and 4.191±0.016 fb-1, respectively, by analyzing large angle Bhabha scattering events. The uncertainties are dominated by systematic effects, and the statistical uncertainties are negligible. Our results provide essential input for future analyses and precision measurements

Determination of the number of ψ(3686) events taken at BESIII

The number of ψ(3686) events collected by the BESIII detector during the 2021 run period is determined to be (2259.3±11.1)×106 by counting inclusive ψ(3686) hadronic events. The uncertainty is systematic and the statistical uncertainty is negligible. Meanwhile, the numbers of ψ(3686) events collected during the 2009 and 2012 run periods are updated to be (107.7±0.6)×106 and (345.4±2.6)×106, respectively. Both numbers are consistent with the previous measurements within one standard deviation. The total number of ψ(3686) events in the three data samples is (2712.4±14.3)×10^

Prediction of Energy Resolution in the JUNO Experiment

International audienceThis paper presents the energy resolution study in the JUNO experiment, incorporating the latest knowledge acquired during the detector construction phase. The determination of neutrino mass ordering in JUNO requires an exceptional energy resolution better than 3% at 1 MeV. To achieve this ambitious goal, significant efforts have been undertaken in the design and production of the key components of the JUNO detector. Various factors affecting the detection of inverse beta decay signals have an impact on the energy resolution, extending beyond the statistical fluctuations of the detected number of photons, such as the properties of liquid scintillator, performance of photomultiplier tubes, and the energy reconstruction algorithm. To account for these effects, a full JUNO simulation and reconstruction approach is employed. This enables the modeling of all relevant effects and the evaluation of associated inputs to accurately estimate the energy resolution. The study reveals an energy resolution of 2.95% at 1 MeV. Furthermore, the study assesses the contribution of major effects to the overall energy resolution budget. This analysis serves as a reference for interpreting future measurements of energy resolution during JUNO data taking. Moreover, it provides a guideline in comprehending the energy resolution characteristics of liquid scintillator-based detectors