Search

Purposes This research aims to improve the stability of energy system power variation and fuel economy during flight of hydrogen-hybrid fixed-wing UAV. Methods A variable equivalent factor considering the influence of battery pack power variation amplitude on energy consumption is introduced on the basis of the traditional equivalent consumption minimization strategy theory. This factor is weighted with the original equivalent factor to form a compound equivalent factor. A UAV hybrid simulation platform suitable for complex flight conditions is established, and the influence of compound equivalent factors on the control effect of equivalent consumption minimization strategy is studied. Findings The results show that the equivalent consumption minimization strategy with compound equivalent factor can effectively reduce the power fluctuation amplitude of the energy system. The amplitude of power fluctuation of hydrogen fuel cell during cruise flight is reduced by 94.7% compared with that of the traditional equivalent consumption minimization strategy, and the accumulative SOC variation of battery pack during flight is reduced by 46%. In 3.5 h flight missions, 193 standard liters of hydrogen can be saved, improving fuel economy. When the SOC of the battery pack approaches equilibrium, the change rate of charging power can be greatly slowed down. The improved equivalent consumption minimization strategy is beneficial to prolonging the service life of energy systems and improving the safety of fuel cells and battery packs.

Despite the recognized importance of addressing belief bias in critical thinking, little is known about the neural activity underlying belief-bias reasoning and its connection to critical thinking. The study utilized event-related potentials (ERPs) to examine the neural responses during belief-bias reasoning and explored the extent to which these ERPs explained individual differences in critical thinking. A sample of university students (N = 72) participated in a belief-bias syllogistic reasoning task while their electroencephalographic data were recorded. The task manipulated conflicts between belief and logic within each syllogism. Additionally, participants completed established tests to assess their critical thinking. Our findings revealed that participants with high levels of critical thinking exhibited larger amplitudes of the P600 and late positive component (LPC), indicating enhanced syntactic analysis and relation integration. Moreover, those with high levels of critical thinking displayed smaller N400 amplitudes, suggesting reduced reliance on automatic semantic processing. Notably, participants, especially those with high levels of critical thinking, demonstrated larger late negative component (LNC) amplitudes in response to incongruent syllogisms than to congruent syllogisms, highlighting their heightened capacity to address conflicts between belief and logic. Furthermore, regression analyses indicated that critical thinking relied on both addressing conflicts between belief and logic, as indexed by the LNC, and generating conclusions, as indexed by the P3 components (including both P600 and LPC). These findings contribute to the theoretical understanding of critical thinking by shedding light on the neural processes associated with unbiased reasoning and metacognition, as well as offer implications for assessing critical thinking. Educational Impact and Implications Statement: We discovered that individuals who possess advanced critical thinking skills demonstrate greater brain activity measured by the P600, and late positive component, while exhibiting smaller N400 amplitudes compared to those with lower-level critical thinking skills. Moreover, variations in critical thinking among individuals can be predicted by the late negative component that reflects the resolution of conflicts between belief and logic during syllogistic reasoning, as well as the P3 components that indicate the generation of logical conclusions. These findings suggest that the electroencephalogram signals associated with solving belief-bias reasoning problems are significant indicators of critical thinking. This discovery offers valuable insights into identifying the neurophysiological markers of critical thinking, potentially leading to the creation of more objective and reliable assessment tools for intervention programs aimed at cultivating critical thinking skills. [ABSTRACT FROM AUTHOR]

To investigate the wall cooling of the thrust chamber in an engine, two film-cooling structures, namely, a circular hole structure and a slot structure, were designed. Numerical simulations were performed to study the coupled flow and regenerative cooling heat transfer in thrust chambers with different structures. The influences of parameters such as the film mass flow rate and film hole size on wall cooling were analyzed. Experiments were conducted in a thrust chamber to validate the accuracy of the numerical calculation method. The results indicate that the slot-structured film adheres better to the wall than the circular-hole-structured film, and the film closely adhering to the wall provides better insulation against hot gas, resulting in a reduction of approximately 6% in wall temperature. When the film hole size changes, the change in circumferential wall temperature in the upstream region of the slot-structured film is more pronounced. This paper aims to provide a reference for the design of the cooling structure at the head of the thrust chamber in engineering and suggests directions for optimization and improvement. [ABSTRACT FROM AUTHOR]

NiFe-LDH/g-C3N4 (LDH/CN) heterostructures with different amounts of NiFe-LDH (LDH) were prepared by a hydrothermal method and characterized using different experimental techniques. Their photocatalytic properties were investigated using the degradation of tetracycline hydrochloride (TC) and the production of hydrogen from water splitting. Experimental results showed that the hydrogen production rate (780.5 μmol g−1 h−1) was 2.29 times that of pristine CN, and the TC removal rate (76.3%) of 1.8LDH/CN was 3.71 times that of CN. According to the detailed study of the structural, optical, and photoelectrochemical properties, a type II charge transfer mechanism was proposed to explain the improved photocatalytic performance of LDH/CN. [ABSTRACT FROM AUTHOR]

Cephalopod skins evolve multiple functions in response to environmental adaptation, encompassing nonlinear mechanoreponse, damage tolerance property, and resistance to seawater. Despite tremendous progress in skin-mimicking materials, the integration of these desirable properties into a single material system remains an ongoing challenge. Here, drawing inspiration from the structure of reflectin proteins in cephalopod skins, a long-term anti-salt elastomer with skin-like nonlinear mechanical properties and extraordinary damage resistance properties is presented. Cation-π interaction is incorporated to induce the geometrically confined nanophases of hydrogen bond domains, resulting in elastomers with exceptional true tensile strength (456.5 ± 68.9 MPa) and unprecedently high fracture energy (103.7 ± 45.7 kJ m -2 ). Furthermore, the cation-π interaction effectively protects the hydrogen bond domains from corrosion by high-concentration saline solution. The utilization of the resultant skin-like elastomer has been demonstrated by aquatic soft robotics capable of grasping sharp objects. The combined advantages render the present elastomer highly promising for salt enviroment applications, particularly in addressing the challenges posed by sweat, in vivo, and harsh oceanic environments., (© 2024 Wiley‐VCH GmbH.)