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A novel combined measurements techniques has been designed in this work, enabling the acquisition of laser-induced breakdown spectroscopy (LIBS) and Raman spectral signals at the same point on a sample. The application of this combined technique to the analysis of multi-layered mock-up blocks painted with orpiment and realgar pigments has yielded significant insights. By correlating variations in the emission line intensity of characteristic elements within the LIBS spectra with depth-specific Raman spectra, the number of laser pulses that penetrated the pigment layers has been accurately determined, thereby establishing a method to measure layer thickness. Finally, the technique wasto analysis the actual mural fragment from Mogao Cave 196, determining the types of pigment and the thickness of the pigment layers. [ABSTRACT FROM AUTHOR]

A new hyperspectral image classification algorithm based on deep learning is constructed to solve the problems of redundant band information, neglect of local details, and insufficient spatial and spectral feature extraction in hyperspectral image classification tasks. The model uses the improved 3D inception structure as a multi-scale feature extractor to enhance the attention to local information, and 3D convolution mixed with 2D convolution (3D-2D) is used as the main feature extractor to improve the conversion and fusion of spatial and spectral features. In addition, a compression-and-excitation network is used as the connecting mechanism for feature transfer to reduce the redundancy of band information and ultimately to realize the effective classification of hyperspectral images. In this paper, the proposed method was validated on three public datasets (Pavia University, Salinas, and Indian Pines), and the results show that the classification accuracies of the proposed method were 99.75, 99.99, and 98.77%, respectively, which are better than the mainstream methods. These results are of great significance for the performance of hyperspectral image classification tasks. [ABSTRACT FROM AUTHOR]

The excitation energies of the Be-like ions (4 ≤ Z ≤ 74) doubly excited state 1 s 2 2 p 2 and doubly core-excited state 2 s 2 p 3 are calculated using the multi-configuration Dirac–Hartree–Fock method. The contributions of relativistic effects, Breit interaction, and QED effects to the excitation energies are analyzed and discussed in detail. A reasonable electron correlation model has been constructed using the active set method. The electron correlation and the finite size of the atomic nucleus correction have also been appropriately considered. The calculated results agree with the available theoretical and experimental data. It is found that the contribution of relativistic effects, Breit interaction, and QED effects to the excitation energy becomes significant with increasing Z. The contribution of the relativistic effects reaches about 8.5% at Z=74. The 3 P 0 level of the doubly excited state 1 s 2 2 p 2 is sensitive to the Breit interaction and the QED effects, but these two contributions cancel each other out. For the doubly core-excited state 2 s 2 p 3 , the Breit interaction and the QED effects are almost equally important, and their maximum contribution is about 0.5%. These results are expected to help future experimental and theoretical work. [ABSTRACT FROM AUTHOR]

The dielectronic recombination of Li-like Xe (2s) ions was studied using the flexible atomic code based on the relativistic configuration interaction method. The resonance energies, radiative and autoionization rates, and resonance strengths were calculated systematically for the doubly excited states (2 p n l )( n = 18−32) and (2 p n′ l )( n′ = 9−27) of Be-like Xe ions. For the higher Rydberg resonance states with n ≥ 33 and n′ ≥ 28, the resonance energies and strengths were obtained by extrapolation based on quantum defect theory. The theoretical rate coefficients, covering the center-of-mass energy range 0-505 eV, are in a better agreement with the experimental results measured at the heavy-ion storage ring ESR than the Multi-Configuration Dirac-Fock calculations, especially at the resonance energy range close to the series limits. Graphical abstract: [ABSTRACT FROM AUTHOR]