135 research outputs found

    Locally Spontaneous Dynamic Oxygen Migration on Biphenylene: A DFT Study

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    The dynamic oxygen migration on the interface of carbon materials, such as graphene and carbon nanotube, has opened up a new avenue to realizing the dynamic covalent materials. However, the understanding of dynamic behaviors of oxygen groups on the non-honeycomb structure, such as the biphenylene sheet, is still limited. Using both density functional theory calculations and ab initio molecular dynamics simulations, we demonstrate that the oxygen groups on the biphenylene, which is an allotrope of graphene and composed of four-, six- and eight-membered rings with unequal C-C bonds, can exhibit locally spontaneous dynamic oxygen migration through the breaking/reforming of the C-O bond. The density of state analyses show that the p-band center of the oxygen atom is closer to the Fermi energy level on biphenylene, compared to that of the oxygen atom adsorbed on graphene. This contrast confirms the locally spontaneous dynamic activity of the oxygen atom on biphenylene. This work provides scientific guidance for the exploration of the locally/globally spontaneous dynamic covalent materials and adds a new member to the 2D dynamic covalent material family.Comment: 13 pages, 4 figure

    DDRF: Denoising Diffusion Model for Remote Sensing Image Fusion

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    Denosing diffusion model, as a generative model, has received a lot of attention in the field of image generation recently, thanks to its powerful generation capability. However, diffusion models have not yet received sufficient research in the field of image fusion. In this article, we introduce diffusion model to the image fusion field, treating the image fusion task as image-to-image translation and designing two different conditional injection modulation modules (i.e., style transfer modulation and wavelet modulation) to inject coarse-grained style information and fine-grained high-frequency and low-frequency information into the diffusion UNet, thereby generating fused images. In addition, we also discussed the residual learning and the selection of training objectives of the diffusion model in the image fusion task. Extensive experimental results based on quantitative and qualitative assessments compared with benchmarks demonstrates state-of-the-art results and good generalization performance in image fusion tasks. Finally, it is hoped that our method can inspire other works and gain insight into this field to better apply the diffusion model to image fusion tasks. Code shall be released for better reproducibility

    Structures of minute virus of mice replication initiator protein N-terminal domain: insights into DNA nicking and origin binding

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    This is the author's accepted manuscript. The original is available at http://www.sciencedirect.com/science/article/pii/S0042682214005236Members of the Parvoviridae family all encode a non-structural protein 1 (NS1) that directs replication of single-stranded viral DNA, packages viral DNA into capsid, and serves as a potent transcriptional activator. Here we report the X-ray structure of the minute virus of mice (MVM) NS1 N-terminal domain at 1.45 Ă… resolution, showing that sites for dsDNA binding, ssDNA binding and cleavage, nuclear localization, and other functions are integrated on a canonical fold of the histidine-hydrophobic-histidine superfamily of nucleases, including elements specific for this Protoparvovirus but distinct from its Bocaparvovirus or Dependoparvovirus orthologs. High resolution structural analysis reveals a nickase active site with an architecture that allows highly versatile metal ligand binding. The structures support a unified mechanism of replication origin recognition for homotelomeric and heterotelomeric parvoviruses, mediated by a basic-residue-rich hairpin and an adjacent helix in the initiator proteins and by tandem tetranucleotide motifs in the replication origins

    Oxygen dissociation on the C3N monolayer: A first-principles study

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    The oxygen dissociation and the oxidized structure on the pristine C3N monolayer in exposure to air are the inevitably critical issues for the C3N engineering and surface functionalization yet have not been revealed in detail. Using the first-principles calculations, we have systematically investigated the possible O2 adsorption sites, various O2 dissociation pathways and the oxidized structures. It is demonstrated that the pristine C3N monolayer shows more O2 physisorption sites and exhibits stronger O2 adsorption than the pristine graphene. Among various dissociation pathways, the most preferable one is a two-step process involving an intermediate state with the chemisorbed O2 and the barrier is lower than that on the pristine graphene, indicating that the pristine C3N monolayer is more susceptible to oxidation than the pristine graphene. Furthermore, we found that the most stable oxidized structure is not produced by the most preferable dissociation pathway but generated from a direct dissociation process. These results can be generalized into a wide range of temperatures and pressures using ab initio atomistic thermodynamics. Our findings deepen the understanding of the chemical stability of 2D crystalline carbon nitrides under ambient conditions, and could provide insights into the tailoring of the surface chemical structures via doping and oxidation.Comment: 23 pages,8 figure

    A study on the double-edged sword effect of inclusive leadership on employees’ work behaviour—dual path perspective of cognition and affection

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    In order to cope with the volatile social environment and organisational change, more and more scholars call on leaders to stimulate subordinate effectiveness to a greater extent with inclusive behaviour. Existing studies focus on the positive impact of inclusive leadership, but ignore its potential negative impact. This study integrates Cognition-affection Personality System Theory to explore the double-edged sword mechanism of inclusive leadership on subordinates’ work behaviour. Through the data analysis of 518 paired questionnaires collected in three stages, the results are as follows: Inclusive leadership has a positive impact on subordinates’ psychological entitlement and state gratitude; Psychological entitlement and state gratitude play mediation roles not only between inclusive leadership and work withdrawal behaviour, but also between inclusive leadership and active behaviour; Subordinate narcissistic personality moderates the positive effect of inclusive leadership on psychological entitlement and state gratitude, and then moderates the indirect effect of inclusive leadership on subordinate work withdrawal behaviour and proactive behaviour through psychological entitlement and state gratitude. The above results expand the research on the action mechanism and boundary conditions of inclusive leadership in Chinese organisational context, and provide practical guidance for organisational managers to effectively conduct inclusive leadership

    AssistSR: Task-oriented Video Segment Retrieval for Personal AI Assistant

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    It is still a pipe dream that personal AI assistants on the phone and AR glasses can assist our daily life in addressing our questions like ``how to adjust the date for this watch?'' and ``how to set its heating duration? (while pointing at an oven)''. The queries used in conventional tasks (i.e. Video Question Answering, Video Retrieval, Moment Localization) are often factoid and based on pure text. In contrast, we present a new task called Task-oriented Question-driven Video Segment Retrieval (TQVSR). Each of our questions is an image-box-text query that focuses on affordance of items in our daily life and expects relevant answer segments to be retrieved from a corpus of instructional video-transcript segments. To support the study of this TQVSR task, we construct a new dataset called AssistSR. We design novel guidelines to create high-quality samples. This dataset contains 3.2k multimodal questions on 1.6k video segments from instructional videos on diverse daily-used items. To address TQVSR, we develop a simple yet effective model called Dual Multimodal Encoders (DME) that significantly outperforms several baseline methods while still having large room for improvement in the future. Moreover, we present detailed ablation analyses. Code and data are available at \url{https://github.com/StanLei52/TQVSR}.Comment: 20 pages, 12 figure

    Multifaceted leaders: the double-edged sword effect of narcissistic leadership on employees’ work behavior

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    So far, most studies have focused on exploring the negative effects of narcissistic leadership. However, little attention has been paid to whether narcissistic leadership also has a positive effect. This study is based on Conservation of Resources Theory and reveals that narcissistic leadership has a double-edged sword effect. By using Mplus7.4 software the analysis of 450 employees and their direct leaders’ pairing data collected in three stages, it is found that: narcissistic leadership has a positive effect on employee’ hostility toward supervisor and psychological availability; hostility toward supervisor mediates the relationship between narcissistic leadership and counterproductive work behavior; psychological availability mediates the relationship between narcissistic leadership and organizational citizenship behavior; in addition, environmental uncertainty enhances the positive effect of narcissistic leadership on employee’ hostility toward supervisor and psychological availability, which in turn moderates the indirect effect of narcissistic leadership on counterproductive work behavior through employee’ hostility toward supervisor and on organizational citizenship behavior through psychological availability
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