Underwater objects often suffer from severe visual degradation, including strong background noise induced by water impurities, blurred boundaries caused by optical scattering, and small object suppression in complex environments. These factors collectively pose significant challenges to underwater object detection (UOD). To address these issues, we propose the Multi-Scale Inverted Pyramid Network (MIP-Net) tailored for UOD. Moving beyond standard feature fusion paradigms, MIP-Net introduces explicit conceptual shifts through two key components: the Local Adaptive Contrast module (LAC) and the Multi-Scale Inverted Feature Pyramid Network (MSIFPN). Unlike conventional global attention mechanisms, LAC selectively calibrates intra-feature contrast layer-by-layer, establishing a theoretical basis for dynamic feature modulation that prevents high-frequency detail dilution. Simultaneously, MSIFPN transcends traditional FPN architectures by coupling a dual-pyramid bidirectional flow with a strict mathematical foreground-background separation strategy, effectively isolating target semantics from ambiguous water impurities. Experiments on the official DUO benchmark demonstrate that MIP-Net achieves an AP of 70.1%, surpassing state-of-the-art single-stage, two-stage, and Transformer-based methods, while maintaining a highly competitive trade-off between computational efficiency (Params/FLOPs) and accuracy. Furthermore, evaluations on the terrestrial COCO dataset yield an AP of 45.6%, confirming the strong cross-domain generalization capability of our framework. The code is publicly available at: https://github.com/YitengGuo/MIP-Net
We report the intrinsic anomalous Hall effect of NdCrGe3 single crystals, which is a hexagonal ferromagnet metal with a one-dimensional crystal structure. The NdCrGe3 undergoes multimagnetic transitions with a ferromagnetic transition at TC<^>101 K and a spin reorientation transition at <^>55 K. The Hall effect indicates that the dominant charge carriers shift from electrons to holes near TC. Large anomalous Hall conductivity <^>681.8 (600.3) Q-1 cm-1 for H//ab (H//c) is observed, consistent with the theoretically anticipated value derived from the intrinsic Berry-curvature mechanism. The linear scaling relationships observed between the anomalous Hall resistivity and the longitudinal resistivity offer strong and convincing evidence indicating that the intrinsic Karplus-Luttinger mechanism, rather than extrinsic side-jump and skew-scattering mechanisms, assumes a dominant position in the anomalous Hall effect. The distinctive crystal structure, unconventional complex magnetic interactions, and the observed intrinsic anomalous Hall effect could make NdCrGe3 as a promising candidate for future electronic devices.
This paper is concerned with the existence of periodic vibrations of the nonhomogeneous strings with linear and nonlinear couplings under some Sturm-Liouville boundary conditions. Such a model is governed by the variable coefficients wave equations and can also be used to describe the simultaneous propagation of seismic waves in nonisotropic media. In the case of linear couplings, the nonlinear self-interactions exhibit sublinear growth with different powers. In the case of nonlinear coupling, the nonlinear self-interactions are characterized by superlinear growth with the same powers as the coupling terms. We prove the existence of infinitely many periodic solutions for these two classes of problems by variational methods and Galerkin approximations under the same working space. Our results are applicable to the uncoupled problems of either homogeneous or nonhomogeneous strings and the coupled problems of the homogeneous strings.
The detection of traffic objects in aerial scenes holds significant application potential in both military and civilian sectors. However, current aerial traffic object detection techniques based on computer vision face challenges including limited awareness of object direction, a heavy computational burden on the feature extraction backbone network, and inadequate capacity to learn crucial semantic information. In this paper, our focus is on investigating the mechanisms for predicting the directional perception of traffic objects in aerial scenes, achieving backbone network lightness, and exploring methods for extracting key semantic information from objects. Firstly, to tackle the challenge of poor perception of traffic object direction and angle in aerial scenes, we utilize techniques like equivariant vector field convolution, multi-task anchor-free prediction, and adaptive loss to develop a precise mechanism for recognizing and predicting object directions. Secondly, given the presence of small-sized and numerous objects in aerial scenes, we propose the adoption of a lightweight backbone network employing channel stacking to decrease the model’s computational burden. Additionally, we establish a theoretical framework and methodology for optimizing and compressing this backbone network, aimed at enhancing feature extraction and propagation for aerial traffic objects. Furthermore, to address the issue of inadequate learning of key semantic information features, we incorporate saliency attention and multi-scale contextual information to capture the essential semantic characteristics of the objects. We also establish a method for extracting semantic features specifically for aerial traffic objects. The approach presented in this paper broadens the applicability of aerial object detection algorithms and offers novel methodologies and theoretical foundations for object detection in intricate scenarios.
A new nickel(II) coordination polymer [Ni2(L)2(bpa)2(H2O)]n·3n(H2O) was solvothermally synthesized with nickel sulfate, 3-hydroxyisonicotinic acid (H2L) and 1,2-bi(4-pyridyl)ethane (bpa). The complicated space structure was confirmed by single-crystal X-ray diffraction analysis. The crystal belongs to the triclinic space group P-1. The L2– ligand bridges the Ni(II) to form a 2D layer, which is connected through bpa ligands to form a 3D framework structure. The thermal properties of the complex were investigated. The magnetic susceptibility data of the complex indicate that dominant antiferromagnetic interactions are mediated between Ni(II) centers.
