In Press
In Press catalogue
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Vol.74 No.12
2025-06-20
2025, 74 (12): 120201.
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2025, 74 (12): 120301.
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2025, 74 (12): 120501.
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Detonation test is affected by small experimental datasets due to high risk of implementation and the huge cost of sample production and measurement. The major challenges of limited data consist in constructing the probability distribution of physical quantities and application of machine learning. Probability learning on manifold (PLoM) can generate a large number of implementations that are consistent with practical common knowledge, while preserving potential physical mechanism these generated samples. So PLoM is viewed as an efficient tool of tackling small samples. To begin with, experimental data are assumed to be concentrated on an unknown subset of Euclidean space and can be treated as the sampling of random vector to be determined. Meanwhile, experimental problem is solved in the framework of matrix and the scaling transformation is conducted on the datasets of PBX9502 with multi-physics attributes. Then the principal component analysis is utilized to normalize the scaling matrix, and the normalization matrix is labeled as training sets. Moreover, the altered multi-dimensional Gaussian kernel density estimation is utilized for estimating the probability distribution of training set. Furthermore, diffusion map is used to discover and characterize the geometry and structure of dataset. In other words, nonlinear manifold based on the training set is constructed through diffusion map. Specifically, the first eigenvalue and corresponding eigenvector is related to the construction of diffusion basis and diffusion maps. Further, Itô-MCMC sampler is associated with dissipative Hamilton system driven by Wiener process, for which the initial condition is set to be training set, and prior probability is conceived as invariant measure. Störmer-Verlet scheme is used for solving the stochastic dissipative Hamilton equations. Finally, additional realizations of learning dataset are fulfilled through the inversion transformation. The result shows that random number generated from PLoM satisfies the requirements of industrial and high fidelity simulation. The 95% confidence interval of density is included in the range calibrated by Los Alamos National Laboratory. And the value of detonation velocity calibrated by Prof. Chengwei Sun [Sun C W, Wei Y Z, Zhou Z K 2000 Applied Detonation Physics (Beijing: National Defense Industry Press) p224] also falls into 95% confidence interval of detonation velocity generated by PLoM. It is also deduced from the learning set that density and detonation velocity satisfies the affine transformation. Furthermore, detonation pressure has nonlinear relationship with density. Tiny variation of density can lead to magnificent fluctuation of detonation pressure and detonation velocity. Detonation pressure has the largest discreetness in all the physical quantities through the comparison of variation coefficients of learning set, which coincides with the existing research results. The method used is universal enough and can be extended to other detonation systems.
2025, 74 (12): 120701.
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During flight operations, aircraft induces atmospheric disturbances in the surrounding environment through aerodynamic interactions between its geometric configuration and ambient air medium, resulting in spatially distinct density distribution characteristics that are significantly different from natural background scenario. Considering the positive correlation between atmospheric medium density and light scattering intensity, theoretical analysis shows that detecting the light scattering intensity signals in disturbed regions can map density distributions, thereby extracting the features of aircraft-induced atmospheric disturbance density fields. Based on the concept of long-range aircraft detection through atmospheric disturbance density field characterization, a novel remote sensing method for aircraft detection is proposed in this work. Specifically, a three-dimensional tomographic imaging detection mode for scattered light in an atmospheric disturbance region is designed, and a comprehensive simulation framework covering the entire process of disturbance optical signal generation, transmission, and response is constructed. The study accomplishes the following tasks: 1) the critical challenges in estimating the imaging modulation transfer function under short-exposure conditions subjected to laser pulse secondary scattering effects are resolved, and a photon scattering echo imaging simulation model for aircraft-induced disturbance density fields is established; 2) the scattering echo signal images from active light sources in disturbed density fields and the differential images obtained under disturbed background and non-disturbed background are simulated, with simulation results under varying system parameters analyzed systematically. The research demonstrates that this simulation model can be used to optimize detection system parameters, develop signal processing methods, and assess long-range detection capabilities, thus providing both theoretical foundations and technical support for advancing aircraft detection technologies based on density disturbance characteristics.
2025, 74 (12): 120702.
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2025, 74 (12): 123101.
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Carbon monoxide cation (CO+) plays a dominant role in some astrophysical atmosphere environments, and theoretical research on its opacity is crucial for modeling radiative transport. In this work, based on experimentally observed vibrational energy levels of the X2Σ+, A2Π, and B2Σ+ electronic states of CO+, the potential energy curves are improved and constructed using a modified Morse (MMorse) potential function, then the vibrational energy levels and spectroscopic constants are extracted. In the meantime, the internally contracted multireference configuration interaction (MRCI) method with Davison size-extensivity correction (+Q) is used to calculate the potential energy curves and transition dipole moments. The refined MMorse potential shows excellent agreement with the computed potential energy curves, while the spectroscopic constants and vibrational levels indicate strong consistency with existing theoretical and experimental data. The opacities of the CO+ molecule is computed at different temperatures under the pressure of 100 atm. The result shows that as temperature rises, the opacities of transitions in the long-wavelength range increases because of the larger population on excited electronic states at higher temperatures. All the data presented in this paper are openly available at https://doi.org/10.57760/sciencedb.j00213.00136 .
2025, 74 (12): 123102.
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The electronic structure of the ICl+ molecular ion is investigated by using high-level multireference configuration interaction (MRCI) method. To improve computational accuracy, Davidson corrections, spin-orbit coupling (SOC), and core-valence electron correlations effects are incorporated into the calculations. The potential energy curves (PECs) of 21 Λ-S states associated with the two lowest dissociation limits I+(1Dg)+Cl(2Pu) and I+(3Pg)+Cl(2Pu) are obtained. The dipole moments (DMs) of the 21 Λ-S states of ICl+ are systematically studied, and the variations of DMs of the identical symmetry state (22Σ+/32Σ+ and 22Π/32Π) in the avoided crossing regions are elucidated by analyzing the dominant electronic configuration. When considering the SOC effect, the Λ-S states with the same Ω components may form new avoided crossing point, making the PECs more complex. With the help of calculated SOC matrix element, the interaction between crossing states can be elucidated. Spin-orbit coupling matrix elements involving the 22Π, 32Π, 12Δ and 22Δ states are calculated. By analyzing potential energy curves of these states and the nearby electronic states, the possible predissociation channels for 22Π, 32Π, 12Δ and 22Δ states are provided. Based on the computed PECs, the spectroscopic constants of bound Λ-S and Ω states are determined. The comparison of the spectroscopic constants between Λ-S and Ω states indicates that the SOC effect has an obvious correction to the spectroscopic properties of low-lying states. Finally, the transition properties between excited states and the ground state are studied. Based on the computed transition dipole moments and Franck-Condon factors, radiative lifetimes for the low-lying vibrational levels of excited states are evaluated. All the data presented in this paper are openly available at https://doi.org/10.57760/sciencedb.j 00213.00140 .
2025, 74 (12): 124101.
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2025, 74 (12): 124201.
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Real-time entropy source evaluated dual-parallel continuous variable quantum random number generator
2025, 74 (12): 124202.
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