2,084 research outputs found

    Investigation of the Structure-Activity Relationship of Pseudo-Single-Crystal Platinum Electrodes by Scanning Electrochemical Microscopy

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    The study of the structure-activity relationship of electrode surfaces is fundamentally important in electrocatalysis research. Yet, the methods and techniques used for the examination of structure-activity relationship so far are limited by their capabilities, and the exploration of electrochemistry at complex surfaces is very challenging. In this study, the correlation between the electrode surface structure and its corresponding activity in two electrochemical reactions were investigated: an electrochemical etching reaction and an electrocatalysis reaction. A polycrystalline Pt electrode was galvanically etched to expose the underlying well-defined crystallites serving as pseudo-single-crystal electrodes. Atomic force microscopy (AFM) complemented with electron backscatter diffraction (EBSD) was employed for the elucidation of the effects of electrode surface structure on its etching rate. Electrochemical measurements of the electrocatalytic activity of the hydrogen oxidation reaction on individual grain surfaces were performed with high spatial resolution scanning electrochemical microscopy (SECM) coupled with electron backscatter diffraction (EBSD). The etching experiment and surface characterization results show the more deeply etched regions on polycrystalline Pt surface correspond to Pt(100). The etching rate of the Pt catalyst is Pt(111), Pt(100), and Pt(110) in increasing order. The structure-reactivity relationship showed that the catalytic activity for hydrogen oxidation reaction (HOR) increases in the order Pt(100) \u3c Pt(110) \u3c Pt(111), where the Miller index plane represents the terrace orientation of the high-index facets. A clear correlation is observed between the increase in HOR activity and step sites density on a given base orientation. Quantitative kinetic measurements at crystal domains were made from current-potential plots and SECM approach curves

    Emotion, emotion regulation and sleep : an intimate relationship

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    In recent years, research has witnessed an increasing interest in the bidirectional relationship between emotion and sleep. Sleep seems important for restoring daily functioning, whereas deprivation of sleep makes us more emotionally aroused and sensitive to stressful stimuli and events. Sleep appears to be essential to our ability to cope with emotional stress in everyday life. However, when daily stress is insufficiently regulated, it may result in mental health problems and sleep disturbances too. Not only does emotion impact sleep, but there is also evidence that sleep plays a key role in regulating emotion. Emotional events during waking hours affect sleep, and the quality and amount of sleep influences the way we react to these events impacting our general well-being. Although we know that daytime emotional stress affects sleep by influencing sleep physiology, dream patterns, dream content and the emotion within a dream, its exact role is still unclear. Other effects that have been found are the exaggeration of the startle response, decrease in dream recall and elevation of awakening thresholds from rapid eye movement (REM), REM-sleep, increased or decreased latency to REM-sleep, increase in percentage of REM-density, REM-sleep duration, as well as the occurrence of arousals in sleep as a marker of sleep disruption. Equally, the way an individual copes with emotional stress, or the way in which an individual regulates emotion may modulate the effects of emotional stress on sleep. The research presented here supports the idea that adaptive emotion regulation benefits our follow-up sleep. We thus conclude the current review with a call for future research in order to clarify further the precise relationship between sleep, emotion and emotion regulation, as well as to explain further how sleep dissolves our emotional stress

    The Sales Impact of Storytelling in Live Streaming E-Commerce

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    Live streaming e-commerce (LSE) has emerged as a popular third-party service for improving product sales. It persuades consumers through streamers’ storytelling or narratives, which encompass descriptions and depictions of their own product experiences. However, the sales impact of a story or narrative in LSEs has been overlooked in the literature. Extending the narrative transportation theory to the LSE context, we posit that the dual landscapes of narrative—the landscapes of action and the landscape of consciousness—can improve product sales through their influence on consumers’ imagination of story plotline and empathy for streamers’ product experiences. We also propose that the efficacy of the dual landscapes is contingent on streamers’ interaction response to consumer query. By collecting LSE data from the Taobao Live platform, we manually and algorithmically measured these variables and proposed to empirically examine their effects

    Optimization design of a micro-perforated panel absorber with 8.6 octave bands

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    In order to improve low-frequency characteristics of micro-perforated panel absorbers, sound absorption structures composed of micro-perforated panels and expansion chambers are design, and an optimization design method is constructed based on the transfer function model and the simulated annealing algorithm. First, a single-chamber structure composed of a micro-perforated panel and an expansion chamber is build, and the sound absorption curve is simulated by the finite element method. Second, for the sake of enlarging the continuous absorption bandwidth with absorption coefficients not less than 0.8, a three-chamber structure is designed, which has a sound absorption bandwidth of 1277Hz (27-1304Hz) covering 5.6 octave bands. Then, the transfer function model of the structure is established, and a series of theoretical formulae are derived to calculate the absorption coefficients. Subsequently, the sound absorption bandwidths calculated by the theoretical formulae and the finite element method are compared, and the relative error is 3.68%. Finally, an optimization design method is constructed by combining the transfer function model and the simulated annealing algorithm, where the optimization objective is to maximize the absorption bandwidth and the optimization variables are structural parameters of the three-chamber structure. The results show, after optimization, the three-chamber structure exhibits an excellent sound absorption performance, with a continuous bandwidth of 1591Hz (4-1595Hz), realizing 8.6 octave bands

    The Sequence Optimization of the Railway Tree-Shaped Special Line\u27s Shunting for Taking-out and Placing-in of Wagons

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    Shunting for taking-out and placing-in of wagons (STPW) is an important work of freight stations, technical stations with more cargo operations, and large intermediate stations.The sequence optimization of STPW can effectively reduce the total shunting time and reduce operating costs, which is of great significance. When the optimization goal is to minimize the total shunting time, there will be many optimal solutions. Therefore, it is necessary to introduce a second optimization objective in order to seek a more reasonable solution from numerous optimal solutions. However, there is no relevant research on this in existing literature. In response to this situation, this paper proposes two optimization objectives: the first is to minimize the total time of STPW, and the second is to minimize the wagon-hour based on minimizing the total time of STPW. Based on the above two optimization objectives, a mathematical model is established, and a three-stage optimization solution strategy is proposed. The first stage is to solve the first optimization objective by using the improved ant colony algorithm; the second stage is to introduce and improve the crossover operation of the genetic algorithm to improve the diversity of the optimal path; the third stage is to solve the second optimization objective. Finally, an example is given to verify the feasibility of the model and the solution strategy
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