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关键词： Aluminum alloys  

摘要： This study designed laser engraving, atmospheric pressure plasma spraying and resin pre-coating (RPC) on aluminum alloy surface to construct quasi-Z-directional "epoxy-pins" for improving bonding strength with carbon fiber reinforce polymer (CFRP). The laser engraving treatment was used to create pitted structure on the aluminum alloy surface, higher wettability was acquired and greater vertical spaces were formed to impregnate epoxy resin for stronger mechanical interlocking. Atmospheric pressure plasma spraying was then utilized to remove surface contaminants of aluminum alloy surface and increase the quantity of adsorbed polar functional groups. RPC technique was further adopted to guide high-viscosity epoxy resin into pits to minimize defects between the resin and the substrate and reinforce the mechanical interlocking. The bonding strength of the specimen with the combined treatments of L0.08-1 yielded up to 130.5% increment than the base in bonding strength. The failure modes of composites were changed from adhesive failure of aluminum alloy surface to delaminationdominated failure of laminated CFRP composites. Simple and effective combined treatment method is expected to gain application in the development of high performance of heterogeneous material bonding. © 2025 Beijing University of Aeronautics and Astronautics (BUAA). All rights reserved.

关键词： Acoustic impedance  

摘要： Triply periodic minimal surface (TPMS), combined with their excellent acoustic properties, has attracted widespread attention in the field of low-frequency broadband sound absorption. In this paper, five types of TPMS sandwich panel structures, namely D, G, P, N, and I-WP, were proposed, and the finite element method was employed to analyze the low-frequency sound absorption performance of these five structures. Experimental validation was conducted by 3D printing P-type and G-type TPMS sandwich structures, and the sound absorption performance of these two structures was tested using the impedance tube method. The experimental results show good consistency with the simulation results. In the context of parameter analysis, the impacts of factors such as TPMS cell type, relative density, thickness of the perforated plate, cell size, and perforation radius on the sound absorption performance of the structure have been investigated. The results show that P sandwich panel with a thickness of 21 mm exhibits excellent sound absorption performance in the range of 512-685 Hz, with a bandwidth ratio of 43.25%. This represents a 9% increase in bandwidth ratio compared to G structure of the same thickness. Additionally, the peak resonance sound absorption coefficient at 540 Hz is 0.83, and the thickness of the structure is only 1/30 of the wavelength corresponding to the peak frequency of the sound absorption coefficient, demonstrating the deep sub-wavelength size characteristic of the P-type structure. D and N cells have high porosity and exhibit good resonance characteristics at a frequency of 400 Hz. The sound absorption bandwidth ratio of the D cells is increased by 17.4% compared to the P cells. As the relative density increases, the porosity of the cells decreases, the resonance frequency rises, and the sound absorption coefficient of the structure gradually decreases. However, the sound absorption bandwidth is slightly broadened. Increasing the thickness of the perforate

关键词： Multilayer films  

摘要： Near-field thermal radiation modulation holds broad application prospects in thermal diodes, thermal transistors, and thermal memory devices. However, designing near-field radiation structures is a complex problem characterized by high degrees of freedom and high computational costs. Machine learning offers more convenient and efficient technical support for the design of new materials. This paper focuses on the thermal regulator based on multilayer film structures of different hyperbolic materials, MoO3 and hBN. By combining autoencoders and Bayesian optimization, we optimize the rotation angles of the multilayer films to achieve the maximum rotational thermal modulation ratio. The optimized multilayer structure achieves a contrast ratio of 11.27, which is greater than the best result of the regulation contrast ratio for homogeneous material combinations. The modulation mechanism is analyzed using the energy transmission coefficient and the near-field thermal radiation spectrum. It is found that the significant modulation contrast obtained is mainly due to the mismatch of the hyperbolic volume phonon polaritons in the type I hyperbolic bands of hBN, providing new insights for the design of near-field thermal radiation transfer. © 2025 Science Press. All rights reserved.

关键词： Sodium-ion batteries  

摘要： The development of low-cost and long-lifespan sodium-ion battery (SIB) cathode materials is crucial for large-scale energy storage. Iron-based phosphate cathode materials have attracted significant attention in recent years for their high theoretical capacity, excellent structural stability and rich resources. Here, a series of Na4FexP4O12+x/C (x=2.6–3.3) electrode materials are prepared using Sol-Gel technique and thermal treatment process. Effect of the phase structure on electrochemical performance of Na4FexP4O12+x/C electrode materials is investigated. It is found that three phases, including Na2FeP2O7 (NFPO), Na4Fe3(PO4)2P2O7 (NFPP) and NaFePO4 (NFP), mainly exist in the Na4FexP4O12+x/C system. Among Na4FexP4O12+x/C electrode materials, Na4Fe3.1P4O15.1/C electrode material with the highest content of NFPP phase possesses rapid electronic and sodium-ion conduction characteristics, thereby exhibiting the optimal electrochemical performance. As a result, the SIB equipped with Na4Fe3.1P4O15.1/C electrode material shows high reversible capacity, with a discharge specific capacity of 102.8 mAh·g–1 at a current density of 0.1C (1C=129 mAh·g–1), as well as capacity retention of 88.7% after 700 cycles. Furthermore, the as-assembled battery exhibits excellent rate performance with a discharge specific capacity of 61.5 mAh·g–1 at a current density of 5C. © 2025 Science Press. All rights reserved.

关键词： Disturbance rejection  

摘要： A forward frequency domain design method for integrating constant pressure drop control valve was proposed， and the contents of the presented study were given: the state space model of the constant pressure drop control valve was derived based on the linear system theory;the explicit relationships between the structural parameters and system performance were established based on the frequency domain analysis method， providing a design guidance of the structural parameters;a dynamic design method was proposed based on the frequency domain design theory， which realized the design of the stabilization control gain;for convenient engineering applications， the concept of design graph for regular orifices was proposed， and the design method of structural parameters for regular orifices was provided. The simulation results showed that， under bad conditions， including the 1 MPa strong step disturbance of the inlet pressure and the significant step disturbance of the metering area，the steady-state working range of the controlled pressure drop was （0.81±0.01） MPa，the static error was less than 1.2%，the settling time was less than 0.002 s， and the phase margin was almost more than 70°. The system had servo tracking and robust disturbance rejection performance. © 2025 Beijing University of Aeronautics and Astronautics (BUAA). All rights reserved.

关键词： 二氧化碳  

ISBN: (纸本)9787122473608

摘要： 本书围绕国内外CCUS技术的最新进展、规模化示范项目案例、技术经济评估、政策支持体系演进及产业化模式设计等核心议题，全面剖析了碳捕集、利用与封存（CCUS）技术在煤电行业中的应用潜力、技术经济性及产业化路径。通过深入的煤电CCUS全流程技术经济评估及基于典型示范项目的分析，不仅揭示了煤电CCUS产业化的发展方向，还构建了一套综合性的政策框架体系，旨在为决策者提供科学依据。

关键词： 多孔性材料  

ISBN: (纸本)9787122447654

摘要： 本书系统介绍多孔材料的类型、结构、性能及应用的研究热点和最新动态。在撰写过程中，对部分国外同行的相关重要工作进行了概述，全书主体内容包括8章，涵盖了目前多孔材料化学的基本研究范畴，系统性强，反映了当前该领域的研究前沿与现状。

关键词： Helmet mounted displays  

摘要： An optical-transmission head-mounted display system offers several advantages, including hands-free operation, continuous functionality under diverse conditions, and 24/7 usability, making it suitable for diverse applications. This study presents a head-mounted display device that uses a free-form prism optical transmissive display method and integrates multispectral sensors within an embedded architecture. We developed an optical display module with a large field of view, high resolution, exceptional light efficiency, low power consumption, and visual adaptability. This was achieved using a domestically manufactured Rockchip 3399 platform and a robust R&D architecture. By optimizing the multispectral sensor quality and parameters, we developed infrared, low-light, and visible-light sensors, along with MicroOLED drivers for the microimage source, resulting in a fully integrated system. Based on the native system, we developed an application that enables seamless switching between multispectral images, thereby achieving an integrated multispectral image display. As a next-generation wearable computing terminal with a high degree of localization, the proposed system demonstrates great promise for applications in park security, industrial inspection, epidemic prevention, temperature monitoring, and multidimensional perception. © 2025 Universitat zu Koln. All rights reserved.

关键词： Magnetron sputtering  

摘要： Graphene film has been widely studied in the field of electromagnetic interference (EMI) shielding due to its unique layered structure, high conductivity, and good flexibility. However, graphene film has a large skin depth, which makes it difficult to balance high shielding effectiveness (SE) and thin thickness. To solve the above problems, the surface modification of graphene film and the design of multi-layer impedance mismatch interface were carried out based on the transmission line theory. The model of metal-graphene multilayer heterostructure was established for electromagnetic simulation. The influence of structural parameters on the EMI shielding performance was studied. According to the simulation model, Ag-graphene-Ag sandwich composite films (A-G-A CF) were fabricated by magnetron sputtering, and their EMI shielding performance and mechanism were investigated. After depositing Ag on graphene film, the conductivity increases by nearly two orders of magnitude, making the skin depth significantly decrease and the SE in 4-18 GHz increase from 24 dB to 44 dB. Moreover, the sandwich structure enhances the electromagnetic loss of the film and further improves the SE to 51 dB. With the increase of metal coating thickness, the SE of A-G-A CF gradually increases. The SE of A-G-A CF with a metal coating thickness of about 580 nm is as high as 65 dB, which can shield more than 99.9999% of electromagnetic wave energy. © 2025 Beijing University of Aeronautics and Astronautics (BUAA). All rights reserved.

关键词： Initial value problems  

摘要： This paper presents a form-finding method for shells resisting external loads through tension-compression mixed membrane stresses. The vertical equilibrium equation of the shell is expressed as a hyperbolic partial differential equation, which is discretized by the finite difference method to obtain a linear system of equations. Existence and uniqueness of the solution can be determined using the coefficient matrix of the equilibrium equations. By introducing regularization and smoothing terms, smooth shapes can be obtained even if the solutions are not unique. The validity of the proposed method is confirmed by comparison with the initial-boundary value problem for wave equations. © 2025 Architectural Institute of Japan. All rights reserved.