253 research outputs found

    Solute segregation in polycrystalline aluminum from hybrid Monte Carlo and molecular dynamics simulations with a unified neuroevolution potential

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    One of the most effective methods to enhance the strength of aluminum alloys involves modifying grain boundaries (GBs) through solute segregation. However, the fundamental mechanisms of solute segregation and their impacts on material properties remain elusive. In this study, we implemented highly efficient hybrid Monte Carlo and molecular dynamics (MCMD) algorithms in the graphics process units molecular dynamics (GPUMD) package. Using this efficient MCMD approach combined with a general-purpose machine-learning-based neuroevolution potential (NEP) for 16 elemental metals and their alloys, we simulated the segregation of 15 solutes in polycrystalline Al. Our results elucidate the segregation behavior and trends of 15 solutes in polycrystalline Al. Additionally, we investigated the impact of solutes on the strength of polycrystalline Al. The mechanisms underlying solute strengthening and embrittlement were analyzed at the atomistic level, revealing the importance of GB cohesion, as well as the nucleation and movement of Shockley dislocations, in determining the material's strength. We anticipate that our developed methods, along with our insights into solute segregation behavior in polycrystalline Al, will be valuable for the design of Al alloys and other multi-component materials, including medium-entropy materials, high-entropy materials, and complex concentrated alloys.Comment: 10 pages, 6 figure

    CAT: Learning to Collaborate Channel and Spatial Attention from Multi-Information Fusion

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    Channel and spatial attention mechanism has proven to provide an evident performance boost of deep convolution neural networks (CNNs). Most existing methods focus on one or run them parallel (series), neglecting the collaboration between the two attentions. In order to better establish the feature interaction between the two types of attention, we propose a plug-and-play attention module, which we term "CAT"-activating the Collaboration between spatial and channel Attentions based on learned Traits. Specifically, we represent traits as trainable coefficients (i.e., colla-factors) to adaptively combine contributions of different attention modules to fit different image hierarchies and tasks better. Moreover, we propose the global entropy pooling (GEP) apart from global average pooling (GAP) and global maximum pooling (GMP) operators, an effective component in suppressing noise signals by measuring the information disorder of feature maps. We introduce a three-way pooling operation into attention modules and apply the adaptive mechanism to fuse their outcomes. Extensive experiments on MS COCO, Pascal-VOC, Cifar-100, and ImageNet show that our CAT outperforms existing state-of-the-art attention mechanisms in object detection, instance segmentation, and image classification. The model and code will be released soon.Comment: 8 pages, 5 figure

    Study on electromagnetic interference and shielding efficiency of power grid on-line elimination equipment

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    The robot-based automatic power grid defect elimination device represents the future direction of power grid inspection and defect elimination devices. However, the presence of strong electromagnetic interference in the vicinity of power grids poses potential risks to the application of automatic defect elimination devices. This study initially conducts theoretical analysis and calculations to analyse the spatial distribution of electromagnetic fields around 220kV 100MW high-voltage lines in a power grid. The results indicate that electric field intensity can exceed 70kV/m in areas near these high-voltage lines. Subsequently, electromagnetic fields within the operational range of the elimination device are simulated and analysed, leading to selection and optimization of shielding materials and structures. When non-metallic insulating materials are used, equipment is fully exposed to the power grid’s electromagnetic field, making internal devices susceptible to interference; however, employing metal aluminum materials achieves better shielding effects. A continuous metal shielding layer effectively shields against electric fields, while openings or gaps in the shell lead to deteriorated shielding performance. These findings demonstrate that appropriate selection of shielding materials and suitable structural design are crucial factors for achieving excellent shielding effects. To ensure both safety and efficient electromagnetic shielding, a multi-layer composite shielding structure is necessary for power grid elimination devices. Overall, these analysis results provide valuable guidance for designing, operating, and maintaining such devices

    Activation of Interleukin-1β Release by the Classical Swine Fever Virus Is Dependent on the NLRP3 Inflammasome, Which Affects Virus Growth in Monocytes

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    Classical swine fever virus (CSFV) is a classic Flavivirus that causes the acute, febrile, and highly contagious disease known as classical swine fever (CSF). Inflammasomes are molecular platforms that trigger the maturation of proinflammatory cytokines to engage innate immune defenses that are induced upon cellular infection or stress. However, the relationship between the inflammasome and CSFV infection has not been thoroughly characterized. To understand the function of the inflammasome response to CSFV infection, we infected porcine peripheral blood monocytes (PBMCs) with CSFV. Our results indicated that CSFV infection induced both the generation of pro-interleukin-1β (pro-IL-1β) and its processing in monocytes, leading to the maturation and secretion of IL-1β through the activation of caspase 1. Moreover, CSFV infection in PBMCs induced the production and cleavage of gasdermin D (GSDMD), which is an inducer of pyroptosis. Additional studies showed that CSFV-induced IL-1β secretion was mediated by NLRP3 and that CSFV infection could sufficiently activate the assembly of the NLRP3 inflammasome in monocytes. These results revealed that CSFV infection inhibited the expression of NLRP3, and knockdown of NLRP3 enhanced the replication of CSFV. In conclusion, these findings demonstrate that the NLRP3 inflammasome plays an important role in the innate immune response to CSFV infection

    Finishing the euchromatic sequence of the human genome

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    The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

    Creative Destruction and Stock Price Informativeness in Emerging Economies

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    It is generally accepted that creative destruction can increase stock price informativeness, for innovative companies tend to behave more surprisingly. However, we believe the rising of stock price informativeness by enterprise innovation in emerging or developing markets is, in some sense, the result of executive ownership and insider trading. To investigate our proposition, we build a rational expectation framework model and define stock price informativeness (SPI) as the Kolmogorov-Smirnov distance between expected distribution and actual distribution of stock prices. Then we use Chinese listed company data to perform benchmark and mediation effects regressions, along with instrumental variable regression in the empirical sector. After that, we use Thailand and Indonesia listed company data for robustness tests. Finally, we divide Chinese listed companies into developed-economy funded and others to do grouping regression. The main conclusion is: Creative destruction can raise stock price informativeness, while executive ownership plays a partial mediating effect in the path of such influence. However, that mechanism is not significant when we use developed-country-funded enterprises listed in China as the sample for regression. Thus, the effects of creative destruction on stock price informativeness are uneven across countries, and executive ownership plays a vital role in that impact in emerging economies

    Regional carbon emission evolution mechanism and its prediction approach: a case study of Hebei, China

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    Removal of Azo Dyes from Aqueous Solution by Composite HKUST-1/GO

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    The adsorption of three kinds of azo dyes from aqueous solution on HKUST-1/graphene oxide (GO) composite was studied in view of the removal efficiency, adsorption isotherm, and regenerate of the sorbent. HKUST-1/GO was found to be with higher dyes removal efficiency than HKUST-1. All the adsorption isotherms of azo dyes on HKUST-1/GO composite followed Freundlich isotherm. The adsorbed azo dyes on HKUST-1/GO could be eluted by acetone, so HKUST-1/GO can also be used for enrichment of azo dyes as adsorbent. </jats:p

    Bonding performance of plywood with pig blood adhesives prepared by a novel method

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    Renewable and eco-friendly pig blood adhesives (PBAs) were obtained by modifying PBAs with a mild alkaline solution and glutaraldehyde and exposing them to an ultrasound treatment. The PBAs were subjected to thermogravimetric (TG) analysis and Fourier transform infrared (FTIR) spectroscopy, and the bonding strength and bonding interface of plywood were analyzed to evaluate bonding performance. The results showed that the alkaline solution unfolded the structure of blood proteins, and the glutaraldehyde crosslinked the blood protein. In addition, the ultrasound greatly increased protein expansion under weak alkaline conditions. The thermal stability of the PBAs exposed to ultrasound treatment under weak alkaline conditions was improved, but the crosslinking agent was not used, and the permeability, which was analyzed by a fluorescence microscope, improved. Further, the average and effective penetration depths on the bonding interface increased 53% and 55%, respectively. The bonding strength of plywood prepared with modified PBAs was greatly improved and compliant with relevant requirements.</jats:p

    The research status of flash flood warning in China

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    The article discusses from the disaster mechanism of flash flood to the current situation of early warning system. The formation of flash flood is closely related to rainfall intensity, underlying surface conditions and antecedent soil moisture content, and analysis of the physical process of flash flood disasters is crucial for the study of flash flood warning. Flash flood disaster warning indexes are mainly divided into two types: rainfall warning index and water level warning index. Data-driven statistical induction method and hydro-hydraulic methods based on physical mechanisms are used to determine rainfall warning index; The water level warning index can be directly determined by the upstream and downstream corresponding water level method or by the disaster water level. And summed up the current situation and development trend of China's flash flood warning research
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