Multi-modal remote sensing images often exhibit complex and nonlinear radiation differences which significantly hinder the performance of traditional feature-based image registration methods such as Scale-Invariant Feature Transform (SIFT). In contrast, structural features—such as edges and contours—remain relatively consistent across modalities. To address this challenge, we propose a novel multi-modal image registration method, Cof-SIFT, which integrates a co-occurrence filter with SIFT. By replacing the traditional Gaussian filter with a co-occurrence filter, Cof-SIFT effectively suppresses texture variations while preserving structural information, thereby enhancing robustness to cross-modal differences. To further improve image registration accuracy, we introduce an extended approach, Cof-SIFT_HOG, which extracts Histogram of Oriented Gradients (HOG) features from the image gradient magnitude map of corresponding points and refines their positions based on HOG similarity. This refinement yields more precise alignment between the reference and image to be registered. We evaluated Cof-SIFT and Cof-SIFT_HOG on a diverse set of multi-modal remote sensing image pairs. The experimental results demonstrate that both methods outperform existing approaches, including SIFT, COFSM, SAR-SIFT, PSO-SIFT, and OS-SIFT, in terms of robustness and registration accuracy. Notably, Cof-SIFT_HOG achieves the highest overall performance, confirming the effectiveness of the proposed structural-preserving and corresponding point location refinement strategies in cross-modal registration tasks.

In order to improve the accuracy of the linear motion of computer numerical control (CNC) machine tools, a novel method based on a new type of 1-D (1-dimensional) artifact is proposed to measure the geometric errors. Based on the properties of the displacement measurement of a revolutionary paraboloid and the angle measurement of plane mirrors, the 1-D artifact can be applied to identify position errors and angle errors. Meanwhile, the concrete 6 degrees-of-freedom error identification method is described in this paper in sufficient detail. Through measuring the 1-D artifact horizontally and vertically using the machine tool, the geometric errors can be obtained by calculating the deviation between the characteristic parameter of the 1-D artifact measured by the machine tool and that measured by a more precise method, for example, laser interferometry. Experiments were carried out on a coordinate measuring machine, and the validity and accuracy of the method were discussed by comparing the result with the identification error measured by a laser interferometer.

Using an optical freeform surface to realize the precision measurement of displacement has become a research focus in the present day. However, the measurement range of this method is limited by the size of the freeform surface processed. In order to overcome this difficulty, this paper presents a two-dimensional displacement measurement system with a large range, which is composed of a slope sensor and a rotating paraboloid array. The slope sensor utilizes the optical structure of an autocollimator with minor optimization, and the rotating paraboloid array expands the measurement range of the system in a discrete manner. The experimental results showed that the optimized optical system enhanced the measurement accuracy to ±0.4 μm within the range of 1500 μm and the overall measurement error was approximately ±2 μm when measured within the range of 450 mm. The developed measurement system has potential applicability for detection of errors, such as the position error and straightness error of multi-axis systems.

The elliptical paraboloid array plays an important role in precision measurement, astronomical telescopes, and communication systems. The calibration of the vertex distance of elliptical paraboloids is of great significance to precise 2D displacement measurement. However, there are some difficulties in determining the vertex position with contact measurement. In this study, an elliptical paraboloid array and an optical slope sensor for displacement measurement were designed and analyzed. Meanwhile, considering the geometrical relationship and relative angle between elliptical paraboloids, a non-contact self-calibration method for the vertex distance of the elliptical paraboloid array was proposed. The proposed self-calibration method was verified by a series of experiments with a high repeatability, within $3\mathsf{\mu }\mathrm{m}$ in the X direction and within $1\mathsf{\mu }\mathrm{m}$ in the Y direction. Through calibration, the displacement measurement system error was reduced from $100\mathsf{\mu }\mathrm{m}$ to $3\mathsf{\mu }\mathrm{m}$ . The self-calibration method of the elliptical paraboloid array has great potential in the displacement measurement field, with a simple principle and high precision.

新型二维材料MA₂Z₄体系因其结构和材料的多样性受到了很大的关注. 其中, 双层VSi₂P₄在AB和BA堆叠情形下同时具有面外铁电极化和层间反铁磁耦合, 具有广泛的应用前景. 本文基于密度泛函理论和非平衡格林函数研究了双层VSi₂P₄范德瓦耳斯多铁器件在不同电极、界面耦合以及结构不对称情况下自旋输运特性. 结果表明, 双层VSi₂P₄的自旋过滤特性导致了Au-VSi₂P₄-Au器件和TiSe₂-VSi₂P₄-TiSe₂器件相对较大的隧穿磁阻, 电极和势垒层的界面耦合造成了相对较小的电致电阻. 通过引入MoTe₂插层, Au-MoTe₂-VSi₂P₄-MoTe₂-Au器件的电致电阻达到17.35%和17.90%, TiSe₂-MoTe₂-VSi₂P₄-MoTe₂-TiSe₂器件电致电阻达到46.25%和49.30%. 在不对称电极Au-MoTe₂-VSi₂P₄-MoTe₂-TiSe₂器件中, 电致电阻进一步扩大至95.3%和94.0%, 同时隧穿磁阻保持相对较大. 这些研究成果有望推动二维本征多铁隧道结以及相关存算一体器件发展.

Flexible perovskite solar cells (F-PSCs) exhibit broad application prospects due to their lightweight and bendable properties. However, uneven substrates and thermal–mechanical deformation during bending hinder the growth of high-quality perovskite films. Meanwhile, stress accumulation at the interfaces of flexible devices aggravates carrier recombination, resulting in deteriorated device performance and stability. Thus, we construct a poly(methyl methacrylate) (PMMA)/[1,1′-biphenyl]-4-carboxamidine hydrochloride (BPhADCl) composite modification layer to synergistically optimize the performance of F-PSCs. Specifically, PMMA can passivate interfacial defects and buffer bending stress. BPhADCl enables the in situ formation of 2D perovskite as nucleation sites to induce the growth of high-quality films, and the formed 2D/3D perovskite heterojunction can block moisture erosion and improve device stability. The optimized F-PSC delivers a champion power conversion efficiency (PCE) of 24.33%, remarkably higher than 20.71% of the control device. After 5000 bending cycles at a bending radius of 5 mm, the device retains 83% of its initial PCE. Moreover, the unencapsulated device maintains 91% of its original efficiency after 1100 h storage under ambient conditions.