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The paper discusses teaching mode of European universities during the epidemic period and proposes the characteristics of digital education which has realized another ideological change from face-to-face teaching to self-learning and from systematic teaching output to individual learning input. Hence the shift can also be understood as the change from digital education to literacy education centered on flexible learning. Based on shift from digital education to literacy education in European universities the developing trend of literacy education in European universities during the epidemic period are put forward in the construction of lifelong education in Europe.

Recently, weak supervision has received growing attention in the field of salient object detection due to the convenience of labelling. However, there is a large performance gap between weakly supervised and fully supervised salient object detectors because the scribble annotation can only provide very limited foreground/background information. Therefore, an intuitive idea is to infer annotations that cover more complete object and background regions for training. To this end, a label inference strategy is proposed based on the assumption that pixels with similar colours and close positions should have consistent labels. Specifically, k‐means clustering algorithm was first performed on both colours and coordinates of original annotations, and then assigned the same labels to points having similar colours with colour cluster centres and near coordinate cluster centres. Next, the same annotations for pixels with similar colours within each kernel neighbourhood was set further. Extensive experiments on six benchmarks demonstrate that our method can significantly improve the performance and achieve the state‐of‐the‐art results. [ABSTRACT FROM AUTHOR]

Microbial electrochemical systems have shown great value as a means of enhancing the efficiency of fermentation reactions, but at present, there is no reliable means to balance the extracellular electron supply and corresponding intracellular demands in these systems. The current work describes the unique use of an oxidation–reduction-potential (ORP)-level-controlled microbial electrolysis cell (MEC) system to successfully balance the extracellular electron supply and succinic acid fermentation via A. succinogenes (130Z). The ORP-controlled MEC system with neutral red (NR) yielded a significant increase in succinic acid production (17.21%). The utilization of NR in this MEC system improved the ORP regulatory sensitivity. The optimal approach to the ORP level control was the use of a −400 mV high-voltage electric pulse-based strategy, which increased the yield of succinic acid by 13.08% compared to the control group, and reduced the energy consumption to 52.29% compared to the potentiostatic method. When compared to the −1 V constant potential MEC system, the high-voltage electric pulse-based ORP strategy for the MEC system control provided sufficient electrons to this system while using less electricity (11.96%) and producing 12.48% (74.43 g/L) more succinic acid during fed-batch fermentation. The electronic utilization efficiency of the ORP-controlled MEC system was 192.02%, which was 15.19 times that of the potentiostatic system. The electronic utilization efficiency is significantly increased in the ORP-controlled MEC system. Succinic acid production is ensured by a high-voltage electric pulse-based method, while the influence on cell growth and power consumption are minimized. Fed-batch fermentation with the high-voltage electric pulse-based ORP strategy for MEC system control is noted to be ideal to achieve a further increase in succinic acid concentration and electronic utilization efficiency. [ABSTRACT FROM AUTHOR]

Direct numerical simulations of temporally evolving high-temperature supersonic turbulent channel flow for chemical equilibrium were conducted with a Mach number of 3.0, a Reynolds number of 4880, and a wall temperature of 1733.2 K to investigate the influence of the viscosity law. The mean and fluctuating viscosity for the mixture rule is higher than that for Sutherland's law, whereas an opposite trend is observed in the mean temperature, mean pressure, and dissociation degree. The Trettel and Larsson transformed mean velocity, the Reynolds shear stress, the turbulent kinetic energy budget, and the turbulent Prandtl number are insensitive to the viscosity law. The semilocal scaling that take into account local variation of fluid characteristics better collapses the turbulent kinetic energy budget. The modified strong Reynolds analogies provide reasonably good results for the mixture rule, which are better than those for Sutherland's law. The streamwise and spanwise coherencies for the mixture rule are stronger and weaker than those for Sutherland's law, respectively. The relationship between viscosity and species components can help to identify the traveling wave packet. [ABSTRACT FROM AUTHOR]

In the setting of adjointable operators on Hilbert $ C^* $ C ∗ -modules, this paper deals with the polar decomposition of the product of three operators. The relationship between the polar decompositions associated with three operators is clarified. Based on this relationship, a formula for the polar decomposition of a multiplicative perturbation of an operator is provided. In addition, a full characterization is made on the polar decomposition of the product of three operators. Some applications of this characterization are also dealt with. [ABSTRACT FROM AUTHOR]

Slag eyes are the upper exposed areas of molten steel in a refining ladle that are formed due to excessive bottom argon bubbling. This phenomenon frequently occurs in the steel-refining process and can lead to slag entrapment and re-oxidation of molten steel. Taking a 150-t industrial steel ladle as the research object, the effects of a dual-plug gas-blown process on the slag-eye size were studied using hydraulic modeling and large-eddy simulations. The experimental results showed that at higher gas flow rates such as 9.1 and 11.7 normal liters/min (Nl/min), the relative central angle of the two porous plugs had a significant effect on the slag-eye size; conversely, at lower gas flow rates, its influence could be ignored. Due to the tendency of the two small slag eyes to merge, the 0.6R–45° (R being the bottom radius of the ladle) case resulted in a larger total slag-eye area compared to the cases with other angles. The 0.6R–135° case showed the most beneficial results for reducing the slag-eye size. Additionally, the numerical simulations helped us to visualize the bubble-uplifting and slag-eye formation processes, and they allowed an exploration of the slag-entrapment mechanism. The simulation results showed that the symmetric gas-blown mode can reduce slag entrapment when compared with the asymmetric mode for the 135°–11.7 Nl/min case; this will be favorable to control the cleanliness of the molten steel. Additionally, analysis of both liquid-level fluctuations and turbulent-kinetic-energy distributions further confirmed the advantages of the symmetric gas-blown mode for suppressing slag entrapment. [ABSTRACT FROM AUTHOR]

β‐Si3N4 powder with well‐dispersed spherical particles was synthesized by liquid‐phase modified carbothermal reduction and nitridation. The influence of the type and content of additives on the particle morphology was investigated. The liquid phase formed at the reaction temperature modifies the morphology of the Si3N4 powder. The Si3N4 products precipitated along the liquid‐solid interface, thus forming a spherical morphology and promoting the transformation from α‐Si3N4 to β‐Si3N4. The type of additives has a strong influence on the formation temperature and viscosity of the liquid phase and hence affects the product morphology. In the samples with CaF2 and CaO additives, sufficient liquid phase occurred and spherical particles were obtained. In the sample with Y2O3, however, the liquid phase was insufficient due to the higher formation temperature, thus resulting in an irregular particle morphology. [ABSTRACT FROM AUTHOR]

Si3N4 ceramics with tailored gradient in color and microstructure were prepared by a rapid cost‐effective one‐step approach. The gradient microstructure was obtained by the manipulation of the dissolution‐reprecipitation process, by controlling the sintering temperature and sintering additive content. In the Si3N4 ceramics, the β‐phase content gradually changed from 84% to 11%. The Si3N4 ceramics exhibited white color on one side and showed a hardness of 19 GPa and fracture toughness of 7 MPa·m1/2 and may be suitable for bio‐implantation applications. [ABSTRACT FROM AUTHOR]