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BackgroundSolid oxide electrolysis cell (SOEC) offers a promising method for converting H2O into H2 at high temperatures ranging from 600 °C to 850 °C. Glass sealants, which are crucial materials in SOEC, fulfill most criteria for an ideal sealant when appropriate glass components at suitable stoichiometric proportions are selected. Nevertheless, they exhibit certain drawbacks, including limited stability, elevated gas leakage rates, and suboptimal thermal cycling performance during the SOEC operation.PurposeThis study aims to evaluate the performance of Al2O3 added Ba-Si-Ca sealant for SOEC.MethodsFirstly, a new Ba-Si-Ca system sealing glass (glass-P) was developed to enhance its properties, such as the coefficient of thermal expansion, glass transition, and softening temperatures, and a series of alumina additions to glass-P, intended for use as the SOEC sealant, were prepared using curtain coating. Then, the coefficients of thermal expansion of these sealants were evaluated using a thermal expansion instrument. The leak rate of the sealants, as well as the impact of different alumina additives on the material's thermal shock resistance and chemical stability, were assessed via a 1-cell stack measurement for extended SOEC operation. Finally, the elemental distribution of the specimen was observed using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (EDS).ResultsThe experimental results show that the leakage rate of the glass P-10 sealant is measured at 5.54×10-3 sccm∙cm-1, which is lower than that of glass P. After undergoing ten thermal cycles, the leakage rate of glass P-10 is found to be 2.275×10-2 sccm∙cm-1, lower than that of the others. An open circuit voltage (OCV) of approximately 1.169 V is recorded for glass P-10 after a 1 053-h test.ConclusionsThe addition of alumina to glass P significantly enhances the sealant's thermal stability and gas tightness.

BackgroundThe performance of solid oxide fuel cells (SOFCs) can be promoted by optimizing cathode materials.PurposeThis study aims to boost the electrochemical performances of cathodes for SOFCs by doping transition metal at the B-site of double perovskite.MethodsFirstly, a series of B-site doped PrBa0.8Ca0.2Co2O5+δ (PBCC) oxides as cathodes for SOFCs were prepared by sol-gel. The effects of B-site doped content and doped elements on the crystalline structure of the cathodes were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). Then, the trends of conductivity and thermal expansion coefficient with B-site doped PBCC oxides were investigated. Finally, the electrochemical performances of cathodes with different B-site doped PBCC oxides were tested to find optimal doping element type and content.ResultsTest results show that polarization is reduced and the electrochemical catalytic activity is improved when 5 mol% of Fe is doped on the B-site of the PBCC cathode. Compared to the PBCC cathode, the max power density of the full cell with a 5-mol% Fe-doped cathode increases from 988 mW∙cm-2 to 1 259 mW∙cm-2 at 700 ℃.ConclusionsThe electrochemical performances of SOFCs can be boosted by modifying the B-site of double perovskite using transition metal.

Aims: We aimed to evaluate the effects of radiofrequency catheter ablation (RFCA) and the factors influencing mortality after RFCA in patients with pulmonary hypertension (PH) and atrial flutter (AFL). Methods and results: Fifty‐eight consecutive PH patients with AFL who underwent an electrophysiological study and RFCA between April 2013 and August 2021 were selected for this study. In the study population, pulmonary arterial hypertension associated with congenital heart disease (PAH‐CHD) was the most common type of PH (n = 34, 59%), followed by idiopathic pulmonary arterial hypertension (IPAH) (n = 19, 33%). Typical atrial flutter was the most common type of atrial flutter (n = 50, 86.2%). Sinus rhythm was restored in 53 (91.4%) patients during RFCA. After a mean follow‐up of 33.8 months, AFL recurred in a total of 22 patients. Nine of them underwent repeat RFCA, and the site of the repeat ablation was not exactly the same as the first. At a median follow‐up of 34.6 months after the last ablation, none of the patients who underwent repeat RFCA experienced AFL recurrence, and all of these patients survived. There were no procedure‐related complications during hospitalization or follow‐up. Univariate Cox regression analysis suggested that AFL recurrence after the last ablation was not associated with all‐cause mortality. NT‐proBNP (HR: 1.00024, 95% CI: 1.00008–1.00041, P = 0.004), pulmonary artery systolic pressure (PASP) (HR: 1.048, 95% CI: 1.020–1.076, P = 0.001), and IPAH (vs. PAH‐CHD, HR: 7.720, 95% CI: 1.437–41.483, P = 0.017) were independent predictors of all‐cause mortality in PH patients with AFL after RFCA. Receiver operating characteristic (ROC) curve analysis revealed that the area under the curve (AUC) of PASP for predicting all‐cause mortality was 0.708. There was no significant difference in the Kaplan–Meier curves for all‐cause mortality between patients with AFL recurrence after the last ablation and those without recurrence (P = 0.851). Patients with higher PASP (≥110 mmHg) and IPAH showed the lower survival rate in Kaplan–Meier curves. Conclusion: Repeat ablation was safe and feasible in patients with recurrent AFL and can maintain sinus rhythm. AFL recurrence was not associated with all‐cause mortality, and patients with high PASP or IPAH were at higher risk for adverse outcomes. [ABSTRACT FROM AUTHOR]

Thermal exchange of underwater water mass caused by marine heat wave is a hot point of research recently. In particular, because the water temperature observation along hot water mass transportation is hard work. Acoustic tomography is an advanced method to measure water temperature variations via sound signal transmission with multi-station network sensing. The 5 kHz frequency acoustic tomography used for observing water temperature variations caused by ocean heat waves is interesting work. In this paper, the numerical simulation of hot water mass is completed first, then floatation and diffusion of hot water mass in a simulation are monitored by acoustic tomography. A new inversion optimization method is proposed to obtain hot water mass transportation variations at two-dimensional temperature vertical profile. The proposed inversion method adds a regularized mode matrix and the optimization method adds the model correlation matrix to improve the results quality. The accuracy of inversion optimization results is compared and discussed, where the mean temperature error is less than 0.4 °C. Sensing water temperature variation of marine heat waves is verified via acoustic signal transmission and improved inversion optimization method. The water dynamical process observation is an application of acoustic tomography, which can be further used observe underwater environmental characteristics. [ABSTRACT FROM AUTHOR]

How to effectively maintain costly intra-group cooperation has always been a topic of great concern in society. As we all know, inter-group competition is a constructive way to promote intra-group cooperation. Previous inter-group competition mechanisms are primarily based on the total contribution value of all individuals in the group in the current round, which ignore the historical behavior of the group and its members. For comparison, we argue that the introduction of collective reputation which reflects not only the total contribution of the groups in the current round but also the group's historical behavior is necessary for the construction of an inter-group competition model. Furthermore, an excellent collective reputation can help the group obtain more high-quality resources and help the group stand out from the competition. To this end, we introduce a new mechanism of inter-group transfer payment driven by collective reputation and construct a public goods game (PGG) model of inter-group competition to study the dynamic behavior of intra-group cooperation evolution. Two parameters, the proportion of accepted groups a and the proportion of transferred groups b , are introduced. The simulation results suggest that the effectiveness of this model in promoting cooperation depends largely on the joint settings of a and b. And in most cases, the combination of small a and medium b plays the significant role. [ABSTRACT FROM AUTHOR]