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关键词： Cable stayed bridges  

摘要： Stay cables are critical load‑bearing components in cable‑stayed bridges. The increasing occurrence of bridge fires poses threats to these cables，yet effective design methods for composite fire‑resistant insulation layer are lacking. A coordinated material‑structure design method for cable fire‑insulation layers under vehicle‑induced fires is proposed，addressing the multi‑scale characteristics of composite fire‑insulation materi‑ als. The optimization equations for material‑structure coordination are established，and a decoupling strategy is presented that separates the coupled optimization problem into structural‑scale design based on finite element heat transfer analysis and material‑scale design based on inverse homogenization methods. The numerical implementation is achieved through CFD‑FEM coupled analysis using MATLAB，PyroSim，and ANSYS. Taking a typical 50 m3 tank truck fire as an example，worst‑case scenario analysis is conducted with a protec‑ tion target of maintaining cable surface temperature below 400 °C. The proposed method is applied to optimize the protective layer composed of basalt fabric composites and high‑silica composites，resulting in a design solu‑ tion that meets the protection requirements. © 2025 Southeast University. All rights reserved.

关键词： Positive temperature coefficient  

摘要： Diamond/Al composites have the advantages of low density, high thermal conductivity and adjustable thermal expansion coefficient, and thus become one of the research hotspots of thermal management materials in recent years. However, Al4C3, the interface product between diamond and Al, will seriously affect the properties of the composites, increase the thermal resistance at the diamond-Al interface, and its easy hydrolysis will easily lead to the failure of the composites in service. In this paper, starting with the negative effects of interface Al4C3 phase, the effects of the current main methods to inhibit interfacial Al4C3 phase (including interfacial control, diamond surface chemical modification, diamond surface modified coating and matrix alloying, etc.) on the interface and thermal conductivity of composites are described in detail. Finally, the development direction of diamond/Al composite heat dissipation materials in future is prospected. © 2025 Beijing University of Aeronautics and Astronautics (BUAA). All rights reserved.

关键词： Delamination  

摘要： The ply level hybridization design employs multiple thin layers instead of a single thick layer, resulting in an increased complexity of the interface. To investigate the hybrid effect between thick and thin plies of laminated composites subjected to low-velocity impact loading, two hybrid laminates were designed based on the quasi-isotropic stacking sequence. The low-velocity impact (LVI) tests including the baseline laminate and hybrid laminates were carried out. The ultrasonic C-scan and de-ply technology were respectively used to make a nondestructive and destructive detection on laminates with impact damages. Impact damages were qualitatively and quantitatively evaluated based on the detection results. Subsequently, the performances and failure modes of compression after impact (CAI) were analyzed. Experimental results show that hybrid design of thick- and thin- plies makes full use of the damage suppression characteristics of thin-ply composite, improves the impact damage resistance of composite structures, reduces the projected delamination area and total interface delamination area, shortens the distance between the largest single delamination and the neutral layer, and significantly improves the CAI strength of composite structures. The outputs of this experimental research serves as an indication for the optimal design and safety evaluation of hybrid structures. © 2025 Beijing University of Aeronautics and Astronautics (BUAA). All rights reserved.

关键词： 电子元件  

ISBN: (纸本)9787122356635

摘要： 本书主要讲解了利用ANSYS Icepak 2024进行电子散热有限元分析的各种方法和技巧，主要内容包括电子热设计基础理论、ANSYS Icepak基础、创建模型、网格划分、物理模型及求解、风冷散热案例、水冷散热案例、热管散热案例、电路板散热案例和参数化优化案例等。

关键词： Research reactors  

摘要： Swimming pool-type reactors have typical advantages such as simple system, high inherent safety, powerful irradiation application function, moderate core size, diverse irradiation channels, and simple operation and maintenance. Among them, Class Ⅱ research reactors have low operating costs and can carry out various low-temperature irradiation tests. Their performance indicators are sufficient to meet the needs of fuel and material testing, production of various medical isotopes, and large-size single crystal silicon doping. They are an indispensable part of my country’s research reactors to achieve high, medium and low power matching. In order to meet the future needs of new reactor fuels, material tests and various neutron applications in my country, an overall design scheme for a new 10 MW multifunctional pool-type research reactor was proposed. At the same time, application facilities such as boron neutron capture therapy (BNCT), large-size single crystal silicon neutron transmutation doping (NTD) channels, horizontal channels and hot columns were set up in the reactor pool area to realize multifunctional neutron application capabilities. Aiming at the core design characteristics of low power, small number of fuel assemblies and anti-neutron well type, the influence of three different forms of control rods and their arrangements on the value of the rods themselves and the core was explored. Taking into account the safety of reactor operation, channel neutron fluence rate, power peak factor and subsequent fuel management methods, the forked control rod form was finally determined. The neutron fluence rate and linear power density in the forked control rod were analyzed to ensure its safety in use. The results show that for each core scheme using forked control rods, the maximum full-power operation days are lower, but the power distribution of the fuel assembly is flat, and the total power peak factor is ＜1.5. Compared with other schemes, the average thermal neutr

关键词： Impact strength  

摘要： The utilization of compacted bentonite as the preferred buffer and backfill material in deep geological repositories for high-level radioactive waste disposal is well established due to its excellent engineering properties. The effectiveness of bentonite in such applications is largely influenced by its mineral composition, particularly the content and type of montmorillonite, a key clay mineral. Montmorillonite's ability to swell and its expansive nature make it highly effective in minimizing the migration of radionuclides and providing stability to the repository structure. In near-field environments, which are the zones closest to the waste container, changes in the physical and chemical properties of montmorillonite, especially its water retention and mechanical strength, have a direct impact on the long-term safety and performance of the repository. The accurate understanding of these properties under various environmental conditions is critical to ensuring that the bentonite buffer effectively isolates the waste over extended time periods. Traditionally, experimental methods such as X-ray diffraction (XRD), scanning electron microscopy (SEM), and various mechanical tests have been used to study the behavior of bentonite. While these techniques provide valuable macroscopic data, they fall short in addressing the molecular and atomic-scale interactions that govern the material's behavior. The hydro-mechanical properties of montmorillonite, which are essential for its performance as a buffer material, depend on the interactions between water molecules and the mineral's surface and interlayer spaces. These interactions occur on the molecular scale, and understanding them requires a more detailed, atomistic approach. This is where molecular dynamics (MD) simulations come into play. This paper reviews the applications of molecular dynamics in clay mineral research, particularly focusing on montmorillonite. It provides an in-depth look at how MD simulations can eluci

关键词： 复合材料  

ISBN: (纸本)9787122464866

摘要： 本书全面介绍了树脂基复合材料的主要成型工艺技术及工程设计方法，紧密结合树脂基复合材料的新科研及生产应用动态，将基础理论知识直接面向应用。在树脂基复合材料成型工艺基础上，着重介绍了复合材料成型工程设计及产品开发全流程的基本过程和方法，从复合材料制品分析、树脂基体设计、成型工艺设计、模具设计、计算机辅助设计、安全环境健康分析等工程过程进行综合分析，并结合实际案例进行分析，综合了工程知识、问题分析、解决方案设计开发，以期达到培养解决复杂工程问题的学科交叉型创新人才的目的。

关键词： Fourier transform infrared spectroscopy  

摘要： Objective Exhaust emissions from motor vehicles have a significant impact on air quality and human health. Among them, nitrogen oxides, the main pollutants in motor vehicles, are particularly critical and highly sensitive to concentration detection. Commonly used NO detection techniques include chemiluminescence (CL), Fourier transform infrared spectroscopy (FTIR), and differential optical absorption spectroscopy (DOAS). However, none of these can easily fulfil the requirements of miniaturization, portability, high sensitivity, and high selectivity of NO detection systems. Faraday rotation spectroscopy (FRS) detects the concentration of molecules by measuring the changes in the rotational signal, whereby the concentration of the paramagnetic absorbing molecules is obtained from the demodulated spin signals. This paper describes the design of a magnetic rotation absorption cell applied to a motor vehicle exhaust NO detection system based on Faraday rotation spectroscopy, and the performance was examined in terms of the characteristics of the magnetic field it can generate. Simulation experiments were conducted to explore the use of this absorption cell in a motor vehicle exhaust NO detection system. Methods A magnetic rotation absorption cell model was constructed based on finite element (FEM) simulations and analysis. The magnetic field characteristics generated by the coil were simulated and analyzed, to fabricate the magnetic rotation absorption cell based on the FEM analysis results and parameters of the coil wire: the diameter and number of turns. The development of the magnetic rotation absorption cell was divided into three steps: cavity design, coil design, and window sheet selection. Repeated experiments and step-by-step approximation methods were used to determine whether the three parts of the absorption cell reached the optimal state, as determined by the quality of the collected spectral lines. A Tesla meter was used to check the magnetic field character

关键词： Binary alloys  

摘要： Inorganic non-metallic biomaterial is one of main types of biomaterials, which is widely used in biomedical fields such as tissue repair, tumor therapy, and drug delivery., making an important contribution to national life and health. Research on inorganic non-metallic biomaterials in China is flourishing, but their production and application are still in the stage of overcoming difficulties. To realize the high-quality development of China's inorganic non-metallic biomaterials and improve their hard power to protect national life and health, this paper analyzes hotspots and difficult problems in research and application of China's inorganic non-metallic biomaterials by means of strategic study. Based on current development opportunities and challenges, some suggestions are proposed for the development of inorganic non-metallic biomaterials, such as material design for unique performance, research on materiobiology, exploration of new principles and mechanisms mediated by materials, customization by intelligent personalization, design through big data screening and artificial intelligence, and standardization based evaluation/regulation. This aims to provide guidance for development of inorganic non-metallic biomedical products and push forward scientific research while accumulating talent resources. © 2025 Science Press. All rights reserved.

关键词： Preforming  

摘要： Using tufting robot, carbon fiber tufted perform was developed. By changing the parameters of tufting and needle punching processes, tufted C/C composites with different structures and a combination of tufting and needle punching C/C composites were prepared. The effects of parameters such as matrix type, mesh felt and needle punching process on the mechanical properties of tufted C/C composites were studied, and the mechanism for the influence of preform structure on the mechanical properties of C/C composites were explored. The results showed that the addition of mesh layer or resin carbon matrix had a positive effect on improving the bending and shear performance of C/C composites. The strength performance of needle punched and tufted C/C composites was better than that of tufted C/C composites, but the introduction of needle punching technology weakened the"pseudo plastic" deformation of stitched C/C composites. © 2025 Beijing University of Aeronautics and Astronautics (BUAA). All rights reserved.