Remaining useful life (RUL) prediction is crucial for enhancing the reliability of complex systems, preventing unexpected failures, and reducing the maintenance costs of electromechanical systems. Data-driven methods, particularly deep learning, have been extensively applied in RUL prediction. However, recent methods have focused solely on long-term features, neglecting the significant role of short-term features in long sequence processes, which leads to an inability to achieve high-precision RUL prediction. In this article, a novel dual-channel network is proposed, which is based on the transformer encoder. Additionally, the approach proposes a robust dual-channel feature extraction layer that integrates a multi-scale convolution block and a gating convolution block. This integrated system is capable of capturing both long-term and short-term features from the raw data simultaneously. Compared to convolutional neural networks, recurrent neural networks and other transformer-based methods, the proposed method is more effective at extracting profound features and focusing on important information in the input. Utilizing the self-attention mechanism, the proposed model captures degradation features and achieves precise RUL prediction. Experiments conducted on the CMAPSS dataset demonstrate that the proposed method outperforms recent RUL prediction methods. The average root mean square error of the proposed method is reduced by 6.8%, and the average score is reduced by 8.5%, proving the effectiveness of the proposed approach.

Topology optimization focuses on the conceptual design of structures, characterized by a large optimization space and a significant impact on structural performance, and has been widely applied in industrial fields such as aviation and aerospace. However, most topology optimization methods prioritize structural stiffness and often overlook stress levels, which are critical factors in engineering design. In recent years, explicit topology optimization methods have been extensively developed due to their ability to produce clear boundaries and their compatibility with CAD/CAE systems. Nevertheless, research on incorporating stress constraints within the explicit topology optimization framework remains scarce. This paper is dedicated to investigating stress constraints within the explicit topology optimization framework. Due to the clear boundaries and absence of intermediate density elements in the explicit topology optimization framework, this approach avoids the challenge of stress calculation for intermediate density elements encountered in the traditional density method. This provides a natural advantage in solving topology optimization problems considering stress constraints, resulting in more accurate stress calculations. Compared with existing approaches, this paper proposes a novel component topology description function that enhances the deformability of components, improving the representation of geometric boundaries. The lower-bound Kreisselmeier–Steinhauser aggregation function is employed to manage the stress constraint, reducing the solution scale and computational burden. The effectiveness of the proposed method is demonstrated through two classic examples of topology optimization.

As the core load-transfer medium in bonded structures, the adhesive layer critically governs overall reliability, with Mode I fracture representing its dominant failure mechanism under tensile loading. This study systematically compares the eXtended Finite Element Method (XFEM) and its two coupled variants—the XFEM-Cohesive Zone Model (CZM) and XFEM-Virtual Crack Closure Technique (VCCT)—in simulating Mode I fractures of adhesive joints. Key comparisons include predictions of stress distribution, load-transfer evolution, and crack propagation paths, all validated through Double Cantilever Beam (DCB) simulations and experiments. Results show that standard XFEM accurately predicts initial stiffness (error < 8%) but overestimates peak load by 10.7%. XFEM-CZM maintains errors below 8% for both stiffness and peak load, while XFEM-VCCT achieves exceptional peak-load accuracy (error < 1%) but overestimates stiffness. In crack evolution, standard XFEM yields an idealized propagation path, whereas the coupled methods reveal a distinct three-stage process. Stress/strain fields in standard XFEM remain stable during propagation, while the coupled approaches exhibit interfacial irregularities before crack arrival, followed by tip concentration and band-like transfer during stable growth. Each method offers distinct advantages, underscoring that selection should align with specific research objectives and modeling requirements.

The predecessor of China Optics was China Optics and Applied Optics Digest, which was founded in 1985. At that time, it was the only retrieval journal in the field of optics in China. At the end of 2008, China Optics and Applied Optics Digest was renamed 《中国光学》的前身是1985年创办的《中国光学与应用光学文摘》，当时是国内光学领域唯一的检索刊物。2008年底《中国光学与应用光学文摘》转型更名为《中国光学与应用光学》期刊，刊载内容突破了文摘的限制，正式成为学术刊物。

Multi-band composite detection is a core technology for achieving high-precision detection of targets at all times and under all weather conditions. To address the laser backscattering issue in the coaxial laser transmit-receive design of conventional multiband optical systems, this paper proposes a four-channel common-aperture composite detection optical system integrating laser emission, laser reception, long-wave infrared detection, and visible-light detection. The system employs an off-axis four-mirror configuration as the front-end telescope system, with a central aperture in the third mirror to accommodate the laser emission channel. This design isolates the laser emission and reception channels and allows the primary and secondary mirrors of the front-end telescope system to be shared, thereby resolving the issue faced by existing large-aperture composite detection schemes incorporating lasers, which require the construction of a separate laser emission system outside the receiving system. The laser emission channel uses an aspheric lens to reshape the Gaussian laser beam into uniform collimated light. A 20× beam expansion is achieved without a focal point, improving illumination uniformity and energy utilization. The three reception channels adopt a common-aperture design with a receiving aperture of 120 mm. After beam passing through the beam-splitting plate, the channels, respectively, meet the requirements of visible-light detection, laser single-photon ranging, and long-wave infrared detection with 100% cold-light-stop efficiency. The system also incorporates environmental adaptability and differentiated tolerance design, enabling stable operation in environments ranging from −40 ^∘ C to 60°C. The results show that the imaging quality, environmental adaptability, and tolerance yield of all channels meet the design requirements, while the obscuration loss remains controllable. This solution achieves integrated emission and reception with a common-aperture design across a broad spectral range (0.48–15 µm), providing a viable technical path for compact multi-wavelength composite detection systems.