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Abrupt permafrost thaw accelerates the decomposition of soil organic carbon and might double the warming caused by the carbon release. However, the influence of thaw slump evolution on carbon dioxide (CO2) emission rates and its drives remains unclear, which induces large uncertainties in the prediction of permafrost carbon‐climate feedback. Here we collected soil samples in the thaw slump landscapes that happened 1–23 years ago on the northern Qinghai‐Tibet Plateau (QTP) and measured the CO2 release rates using a 189‐day aerobic laboratory incubation in the dark. The incubation results showed that thaw slump occurred 23 years ago reduced soil CO2–C release by 57 ± 19% compared with the undisturbed area. The relative contribution of O‐alkyl C and microbial abundance decreases with the thaw slump initiation time lengthens. We illustrate that soil carbon quality and microbial communities uniquely explained 41% and 13% of the variation in CO2–C release, respectively. We preliminary estimate that the carbon release for thaw slump landscapes on the QTP may be overestimated by approximately 50% if the declining soil CO2–C release is without consideration. Our study highlights the CO2–C release would decrease with the stability of thaw slumps on the warming and wetting QTP, which may weaken the mountain permafrost carbon‐climate feedback. Plain Language Summary: Rapid warming of permafrost regions leads to the widespread development of thaw slumps and accelerates the decomposition and release of soil organic carbon. Yet, how the evolution of thaw slump affects CO2 release remains unclear. We found that CO2 release gradually decreased with the thaw sequence. Labile carbon (O‐alkyl C) proportion and microbial abundance declined along the thaw sequence, while resistant carbon (alkyl C) proportion increased. Soil carbon quality and microbial communities are important factors controlling CO2 release. Applying the results to the entire Tibetan Plateau, we find that permafrost carbon emissions would be overestimated by approximately 50% if the declining soil CO2 release of stabilized thaw slump is without consideration. Our findings suggest that stable thaw slump can weaken CO2 release. Therefore, the assessment of mountain permafrost carbon feedback needs to consider the effect of thaw slump evolution. Key Points: Soil CO2 release was reduced by 57% in areas that collapsed for 23 years compared to the control areasThaw slump leads to a large decrease in O‐alkyl C and soil microbial abundanceSoil carbon quality and microbial communities exert the controls of 41% and 13% over CO2 release, respectively [ABSTRACT FROM AUTHOR]

Large amounts of soil organic carbon (SOC) have accumulated over thousands of years in the northern permafrost regions. However, the SOC accumulation rates and the effects of topography, vegetation, and soil properties on SOC storage remain poorly constrained, leading to large uncertainties in the estimation of SOC storage and its response to warming. Here, we examined SOC stocks, densities, and accumulation rates using field sampling and radiometric dating in areas with different topographic parameters on the northern Qinghai–Tibet Plateau. Results show that SOC density and stock increases with elevation on south‐facing slopes but decreases with elevation on north‐facing slopes. The carbon accumulation rates in the upper 6 m soil are highest (16.32 g C m−2 year−1) in the north‐facing alpine wet meadow and lowest (1.07 g C m−2 year−1) in the south‐facing alpine steppe. Elevation‐, slope‐, and slope aspect‐induced variations in soil properties and vegetation type are the main factors controlling the spatial SOC distribution. These results imply that the topography strongly affects the spatial heterogeneity of SOC in mountainous permafrost regions. Overall, our findings highlight that topographic factors should be further integrated into carbon models of carbon responses to climate change in permafrost‐affected soils. [ABSTRACT FROM AUTHOR]

As an essential part of modern intelligent decision-making science, multi-attribute decision-making problems can effectively select and rank all candidate schemes under multiple indicators. Because of the complexity of the real environment and the uncertainty of the decision-making problem, interval numbers are often used to represent the evaluation information of the object. The existing methods of the multi-attribute decision-making problems rarely use the object set but give the decision results by selection or ranking, which often have strong subjectivity. We propose a ranking method from an acceleration viewpoint based on the three-way decision model to solve the interval-valued multi-attribute decision-making problem. A distance measure of two objects is a measure that describes the relationship between objects. Therefore, the fuzzy dominance distance is introduced to express order relations among objects. First, we present a method to compare any two interval numbers, which converts interval numbers into connection numbers according to the characteristics of interval numbers in multi-attribute decision-making problems. Second, the three-way decision theory is introduced to divide the object set into high, medium, and low dominance regions for the speed and rationality of decision-making. Finally, the multi-attribute decision-making problems can be simplified into the problem of selection in three regions by ranking the objects of the selected region. Unlike traditional methods, the experiments demonstrate that our proposed method has the lowest cost. Our method is shown to be efficient and can obtain comparable results. [ABSTRACT FROM AUTHOR]

In this work, the plasma generated by the cascaded SinplexProTM plasma spray gun was studied by means of numerical simulation. Special attention is given to the laminarity of the plasma flow. The simulation part is divided into two parts: arcing simulation inside the spray gun and plasma jet simulation outside the spray gun. A laminar as well as a turbulent model is used in each case. The results show that, under the investigated conditions, the internal flow of the plasma torch can be considered as laminar with low turbulence and can, hence, be regarded as quasi-laminar flow. If carrier gas is injected into the plasma jet, the ideal laminar plasma jet is often greatly affected. However, the turbulent plasma jet with low turbulence intensity generated by the cascaded SinplexProTM plasma spray gun is less affected and can remain stable, which is beneficial to the plasma-spraying process. [ABSTRACT FROM AUTHOR]

With the rapid development of cloud computing and mobile Internet technology, the information of optional services in the network is exploding and the problem of information overload is becoming more and more serious. The recommendation system can recommend suitable English online classes for students according to their interests and needs, effectively reduce the data load, help students extract effective information from the mass of information, and make accurate recommendations. Aiming at the problems of data sparsity and cold start in the recommendation system, this paper proposes a recommendation method to improve the collaborative recommendation algorithm in college English online classroom teaching practice. Based on the extracted student tag feature information, this method uses spectral clustering algorithm to cluster similar students and transforms the original high-dimension scoring matrix into several lower-dimension subscoring matrices. Then, the implicit meaning model is used to locally predict the missing score in the subscore matrix. Finally, after obtaining the missing score, the improved neighborhood-based collaborative recommendation algorithm is used to predict the global score of the target student. Experiments are performed on commonly used public data sets. Compared with the traditional recommendation algorithm, the proposed algorithm has higher recommendation accuracy and better RMSE performance. [ABSTRACT FROM AUTHOR]

In this work, La1−xBixFeO3 powders (0 ≤ x ≤ 0.2) were prepared by sol-gel route. The orthorhombic Pbnm structure of the pure LaFeO3 powder was confirmed by X-ray diffraction. However, there was a changing tendency from the orthorhombic Pbnm structure into the rhombohedral R3c structure with the increase in Bi-doping. The structural and symmetric change of Bi-doped LaFeO3 samples was further verified by the Raman spectra which changed from fundamental 5 modes into 7 modes. The X-ray photoelectron spectra (XPS) revealed that more oxygen vacancies, Fe3+ and Fe4+, existed in Bi-doped LaFeO3 sample. Detailed CV, LSV and EIS analyses had provided conclusive evidence that the oxygen vacancy Fe3+ and Fe4+ played an important contribution to the electrocatalytic activity. The best ORR catalytic effect was observed in La0.85Bi0.15FeO3 catalyst. These results suggest that the Bi-doping is a significative effort to enhance the activities of perovskite electrocatalysts. [ABSTRACT FROM AUTHOR]

The catalysts are often used in fuel cells and metal-air batteries to speed up electrochemical reactions. In this study, we prepared CoFe 2 O 4 nanoparticles with mainly inverse spinel structure and FeCo 2 O 4 nanoparticles with mainly spinel structure as bifunctional catalysts by hydrothermal method. After annealing at 350 °C, pure CoFe 2 O 4 and FeCo 2 O 4 nanoparticles with uniform size distribution have been obtained. The CoFe 2 O 4 nanoparticles showed high current density of 5.5 mA/cm2 at −0.8 V in the ORR test. It's low Tafel slope of 83.0 mV/dec further confirmed the excellent ORR catalytic properties of CoFe 2 O 4 nanoparticles. Furthermore, the CoFe 2 O 4 nanoparticles also showed good OER properties with satisfied current density of 35.7 mV/cm2 at l.0 V and low OER Tafel slope of 71.0 mV/dec. Both the ORR and OER properties of CoFe 2 O 4 nanoparticles showed good time stability which were compared with FeCo 2 O 4 nanoparticles. These results indicated that CoFe 2 O 4 nanoparticles with mainly inverse spinel structure had better electrocatalytic performance than FeCo 2 O 4 nanoparticles with mainly spinel structure. The CoFe 2 O 4 nanoparticles with mainly inverse spinel structure show a significant potential application in rechargeable battery. Image 1 • The work used a simple, convenient and cheap method to prepare pure spinel oxides. • The relationship between spinel structure and electrocatalytic properties was studied. • We confirmed normal spinel structure and inverse spinel structure can coexist in spinel nanoparticles. [ABSTRACT FROM AUTHOR]