The observation of very high energy (VHE, > 100GeV) photon from γ-ray bursts (GRBs) can advance our understanding of their radiation mechanism, the evolution of host-galaxies, violations of Lorentz invariance, ext...
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The KM2A is a major ground-based array for the researches on cosmic rays around the "knee" region and the ultra high energy gamma-ray astronomy, which depends heavily on its performance. The half array of th...
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Metal catalysts for the CO 2 reduction reaction (CO 2 RR) face challenges such as high cost, limited durability, and environmental impact. Although various structurally diverse and functional metal-free catalysts have...
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Metal catalysts for the CO 2 reduction reaction (CO 2 RR) face challenges such as high cost, limited durability, and environmental impact. Although various structurally diverse and functional metal-free catalysts have been developed, they often suffer from slow kinetics, low selectivity, and nonrecyclability, significantly limiting their practical applications. In this study, we introduce a recyclable nonmetallic polymer material (vitrimer) as a catalyst for a new platform in contact-electrocatalysis. This approach harnesses the contact charges generated between water droplets and vitrimer to drive CO 2 RR, achieving methanol selectivity exceeding 90%. The imine groups within the vitrimer play a dual role, facilitating CO 2 adsorption and enriching friction-generated electrons, thereby mediating efficient electron transfer between the imine groups and CO 2 to promote CO 2 RR. After 84 h of CO 2 RR, the system achieved a methanol production rate of 13 nmol·h −1 , demonstrating the excellent stability of the method. Moreover, the vitrimer retains its high-performance electrocatalytic activity even after recycling. Mechanistic studies reveal that, compared to traditional metal catalysts, the N─O bond in the imine, which adsorbs the key intermediate *OCH 3 , breaks more readily to produce methanol, resulting in enhanced product selectivity and yield. This efficient and environmentally friendly contact-electroreduction strategy for CO 2 offers a promising pathway toward a circular carbon economy by leveraging natural water droplet-based contact-electrochemistry.
The software application of the discrete logarithms on the 'large' finite field is studied. The most effective algorithm for the problem is the general number field sieve (GNFS). Focusing on the theory of GNFS...
The software application of the discrete logarithms on the 'large' finite field is studied. The most effective algorithm for the problem is the general number field sieve (GNFS). Focusing on the theory of GNFS of solving software Cado-NFS and lattice sieves, we find the selection of lattice sieve which improve efficiency of CADO-NFS. This is the first parameter modification suggest. The efficiency of our selection is better than the current by experiment.
The Large High Altitude Air Shower Observatory (LHAASO) is a new generation hybrid cosmic ray observatory which is expected to reveal the mystery of the origin of cosmic rays. The one square kilometer array (KM2A) con...
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Graph centrality can be estimated by random walk algorithms such as PageRank. These algorithms are useful when ranking items with relationships, and are based on global structure of the graph. It needs to traverse the...
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Graph centrality can be estimated by random walk algorithms such as PageRank. These algorithms are useful when ranking items with relationships, and are based on global structure of the graph. It needs to traverse the entire edge-set more than once to get a convergent result. However, when it comes to large graphs, traversing the whole graph is costly, especially when a single node's information is wanted. How to get a rough look at the rank of a specific node? Can the methods be simpler that don't bother to scan the entire graph? How to scale up the method to get more information of the graph? In this paper, we proposed a simple and light algorithm to get approximate rank value of a node. It could be simplified by sampling and expanded to distributed environment. Experiments on representative public graphs have shown that the method can provide an approximate ranking. And the higher ranking a node has by global algorithms, the more accurate the approximate rank will be. Our method also reduces the computation to several orders of magnitude than traditional global algorithms. With sampling techniques, it can outperforms the basic method by additionally reducing computation. It is useful in both estimation and edge computing.
The origin of PeV cosmic rays in the Galaxy is a long-standing puzzle. Superbubble or massive star cluster (MSC) has been suggested as powerful cosmic-ray accelerators. Cygnus Cocoon, an extended gamma-ray source, is ...
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With the development of computer vision research, the architecture of convolutional neural network becomes more and more complex to reach the state-of-the-art performance. Is the complexity of the model necessarily pr...
With the development of computer vision research, the architecture of convolutional neural network becomes more and more complex to reach the state-of-the-art performance. Is the complexity of the model necessarily proportional to its accuracy? To answer this, the compression of the network has attracted much attention in the academy and industry. Existing network pruning methods mostly rely on the scoring mechanism of complexity or diversity of kernels to compress the network, and then build the network model after removing the kernels by tuning or training on the input data. These methods are cumbersome and depend on a well-trained pre-trained model. In this paper, we propose an end-to-end block pruning method based on kernel and feature stability by pruning blocks efficiently. To accomplish this, we firstly introduce a mask to scale the output of the blocks, and the L1 regularization term to monitor the mask update. Second, we introduce the Center Loss to guarantee that the feature does not deviate greatly during learning. To converge fast, we introduce fast iterative shrinkage-thresholding algorithm (FISTA) to optimize the mask, by which a more fast and reliable pruning process is achieved. We implement experiments on different datasets, including CIFAR-10 and ImageNet ILSVRC2012. All the experiments have achieved the state-of-the-art accuracy.
The current image steganography algorithms mainly focus on the anti-detectability rather than the robustness to scaling attacks. Therefore, it is difficult to extract the secret messages correctly after stego images s...
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The square kilometer array (KM2A) is the main array of the Large High Altitude Air Shower Observatory (LHAASO), which is the most sensitive gamma-ray detector for energies above a few tens of TeV. We are developing a ...
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