分类： 天文学 >> 天文学 提交时间： 2024-03-29 合作期刊: 《Research in Astronomy and Astrophysics》
摘要： Galaxy morphology classifications based on machine learning are a typical technique to handle enormous amounts of astronomical observation data, but the key challenge is how to provide enough training data for the machine learning models. Therefore this article proposes an image data augmentation method that combines few-shot learning and generative adversarial networks. The Galaxy10 DECaLs data set is selected for the experiments with consistency, variance, and augmentation effects being evaluated. Three popular networks, including AlexNet, VGG, and ResNet, are used as examples to study the effectiveness of different augmentation methods on galaxy morphology classifications. Experiment results show that the proposed method can generate galaxy images and can be used for expanding the classification model's training set. According to comparative studies, the best enhancement effect on model performance is obtained by generating a data set that is 0.5–1 time larger than the original data set. Meanwhile, different augmentation strategies have considerably varied effects on different types of galaxies. FSL-GAN achieved the best classification performance on the ResNet network for In-between Round Smooth Galaxies and Unbarred Loose Spiral Galaxies, with F1 Scores of 89.54% and 63.18%, respectively. Experimental comparison reveals that various data augmentation techniques have varied effects on different categories of galaxy morphology and machine learning models. Finally, the best augmentation strategies for each galaxy category are suggested.
分类： 物理学 >> 核物理学 提交时间： 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要： Fluorescence spectroscopy was employed to investigate the interaction between fluorophore fluoresceinamine (FA) and bovine serum albumin (BSA) under physiological conditions. In the mechanism discussion, it was proved that the fluorescence quenching of BSA by FA is a result of the formation of a BSA-FA complex. Fluorescence quenching constants were determined using the modified Stern-Volmer equation to provide a measure of the binding affinity between FA and BSA. The results of the thermodynamic parameters G, H, and S at different temperatures indicated that several kinds of interactions, except for the electrostatic interactions play cooperative roles in BSA-FA association. Furthermore, the conformation of BSA upon interaction with FA was also studied by synchrotron fluorescence spectroscopy.
分类： 物理学 >> 核物理学 提交时间： 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要： Peptide GAV-9 is derived from 3 different disease related proteins. The self-assembly of GAV-9 in a water nanofilm attracted much attention recently. We studied how the temperature factor influenced the peptide self-assembly in a water nanofilm and found interesting phenomena: 1) the higher the temperature, the faster the nanofilaments grow; 2) the GAV-9 peptide formed double monolayers in a water nanofilm at 60 ℃, which further supports the hypothesis that the water nanofilm could change the hydrophobicity of mica. We believe these results can help not only the microcontact printing of amyloid peptides, but also a better understanding on how temperature controls the properties of water nanofilm.
分类： 物理学 >> 核物理学 提交时间： 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要： Bio-nanosensors (Bio-NSs) have attracted much attention recently due to their unique properties. Among all of the bio-NSs, the intracellular proton sensor is significant for biomedicine studies and clinic diagnosis. Proton nanosensors (PNSs) with different pH sensitive ranges could satisfy different research requirements. Here we report a facile method to build a PNS with a neutral to basic pH sensitive range, in which the commercial pH indicator, fluoresceinamine (FA), was covalently coupled to the carboxylic-rich amphiphilic polymer (AP) coated gold nanoparticles (AuNPs).
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