In recent years,there has been a growing global demand for carbon neutrality and energy efficiency,which are expected to become long-term trends.In the field of architecture,an effective approach to achieve this is to...In recent years,there has been a growing global demand for carbon neutrality and energy efficiency,which are expected to become long-term trends.In the field of architecture,an effective approach to achieve this is to reduce heat loss in buildings.Vacuum insulation panels(VIPs),a type of high-performance insulation material,have been increasingly utilised in the construction industry and have played an increa-singly important role as their performance and manufacturing processes continue to improve.This paper provides a review of the factors affecting the thermal conductivity of VIPs and presents a detailed overview of the research progress on core materials,barrier films,and getters.The current research status of VIPs is summarised,including their thermal conductivity,service life,and thermal bridging effects,as well as their applications in the field of architecture.This review aims to provide a comprehensive understanding for relevant practitioners on the factors influencing the thermal conductivity of VIPs,and based on which,measures can be taken to produce VIPs with lower thermal conductivity and longer service life.展开更多
The increasing demand to decrease manufacturing costs and weight reduction is driving the aircraft industry to change the use of conventional riveted stiffened panels to integral stiffened panels(ISP)for aircraft fuse...The increasing demand to decrease manufacturing costs and weight reduction is driving the aircraft industry to change the use of conventional riveted stiffened panels to integral stiffened panels(ISP)for aircraft fuselage structures.ISP is a relatively new structure in aircraft industries and is considered the most significant development in a decade.These structures have the potential to replace the conventional stiffened panel due to the emergence of manufacturing technology,including welding,high-speed machining(HSM),extruding,and bonding.Although laser beam welding(LBW)and friction stir welding(FSW)have been applied in aircraft companies,many investigations into ISP continue to be conducted.In this review article,the current state of understanding and advancement of ISP structure is addressed.A particular explanation has been given to(a)buckling performance,(b)fatigue performance of the ISP,(c)modeling and simulation aspects,and(d)the impact of manufacturing decisions in welding processes on the final structural behavior of the ISP during service.Compared to riveted panels,machined ISP had a better compressive buckling load,and FSW integral panels had a lower buckling load than riveted panels.Compressive residual stress decreased the stress intensity factor(SIF)rates,slowing down the growth of fatigue cracks as occurred in FSW and LBW ISP.展开更多
This study systematically examines the energy dissipation mechanisms and ballistic characteristics of foam sandwich panels(FSP)under high-velocity impact using the explicit non-linear finite element method.Based on th...This study systematically examines the energy dissipation mechanisms and ballistic characteristics of foam sandwich panels(FSP)under high-velocity impact using the explicit non-linear finite element method.Based on the geometric topology of the FSP system,three FSP configurations with the same areal density are derived,namely multi-layer,gradient core and asymmetric face sheet,and three key structural parameters are identified:core thickness(t_(c)),face sheet thickness(t_(f))and overlap face/core number(n_(o)).The ballistic performance of the FSP system is comprehensively evaluated in terms of the ballistic limit velocity(BLV),deformation modes,energy dissipation mechanism,and specific penetration energy(SPE).The results show that the FSP system exhibits a significant configuration dependence,whose ballistic performance ranking is:asymmetric face sheet>gradient core>multi-layer.The mass distribution of the top and bottom face sheets plays a critical role in the ballistic resistance of the FSP system.Both BLV and SPE increase with tf,while the raising tcor noleads to an increase in BLV but a decrease in SPE.Further,a face-core synchronous enhancement mechanism is discovered by the energy dissipation analysis,based on which the ballistic optimization procedure is also conducted and a design chart is established.This study shed light on the anti-penetration mechanism of the FSP system and might provide a theoretical basis for its engineering application.展开更多
针对太阳能电池表面存在的各种缺陷严重影响能量转换效率的问题,提出一种基于改进YOLO11的高效多尺度特征学习模型(efficient multi-scale feature learning based on YOLO11,YOLO11-EMFL),专门用于快速准确地检测太阳能电池中的表面缺...针对太阳能电池表面存在的各种缺陷严重影响能量转换效率的问题,提出一种基于改进YOLO11的高效多尺度特征学习模型(efficient multi-scale feature learning based on YOLO11,YOLO11-EMFL),专门用于快速准确地检测太阳能电池中的表面缺陷。该模型在骨干和颈部网络中引入小波卷积以增加感受野,同时将可变形注意力机制引入骨干网络中,以增强对不同图像大小和图像内容的适应能力。此外,在颈部网络中加入特征融合层以增强多尺度特征融合能力,并在小目标检测层引入三重注意力机制以提高对小目标的检测精度。这些改进使得YOLO11-EMFL网络能够有效地应对不同缺陷种类、缺陷尺寸以及复杂背景的挑战。通过在大规模光伏电池图像数据集上的验证,实验结果显示,YOLO11-EMFL的精确率达到91.8%,召回率为93.8%,F1分数为92.0%,mAP@50和mAP@50-95分别为98.2%和76.9%,在12种缺陷上展现出极高的检测精度。与当前的其他方法相比,该模型的各方面性能都有提升。展开更多
文摘In recent years,there has been a growing global demand for carbon neutrality and energy efficiency,which are expected to become long-term trends.In the field of architecture,an effective approach to achieve this is to reduce heat loss in buildings.Vacuum insulation panels(VIPs),a type of high-performance insulation material,have been increasingly utilised in the construction industry and have played an increa-singly important role as their performance and manufacturing processes continue to improve.This paper provides a review of the factors affecting the thermal conductivity of VIPs and presents a detailed overview of the research progress on core materials,barrier films,and getters.The current research status of VIPs is summarised,including their thermal conductivity,service life,and thermal bridging effects,as well as their applications in the field of architecture.This review aims to provide a comprehensive understanding for relevant practitioners on the factors influencing the thermal conductivity of VIPs,and based on which,measures can be taken to produce VIPs with lower thermal conductivity and longer service life.
基金The authors express their gratitude to Universiti Pura Malaysia(UPM),Malaysia for granting Putra IPS vote number 9742900.
文摘The increasing demand to decrease manufacturing costs and weight reduction is driving the aircraft industry to change the use of conventional riveted stiffened panels to integral stiffened panels(ISP)for aircraft fuselage structures.ISP is a relatively new structure in aircraft industries and is considered the most significant development in a decade.These structures have the potential to replace the conventional stiffened panel due to the emergence of manufacturing technology,including welding,high-speed machining(HSM),extruding,and bonding.Although laser beam welding(LBW)and friction stir welding(FSW)have been applied in aircraft companies,many investigations into ISP continue to be conducted.In this review article,the current state of understanding and advancement of ISP structure is addressed.A particular explanation has been given to(a)buckling performance,(b)fatigue performance of the ISP,(c)modeling and simulation aspects,and(d)the impact of manufacturing decisions in welding processes on the final structural behavior of the ISP during service.Compared to riveted panels,machined ISP had a better compressive buckling load,and FSW integral panels had a lower buckling load than riveted panels.Compressive residual stress decreased the stress intensity factor(SIF)rates,slowing down the growth of fatigue cracks as occurred in FSW and LBW ISP.
基金the National Natural Science Foundation of China(Grant Nos.11972096,12372127 and 12202085)the Fundamental Research Funds for the Central Universities(Grant No.2022CDJQY004)+4 种基金Chongqing Natural Science Foundation(Grant No.cstc2021ycjh-bgzxm0117)China Postdoctoral Science Foundation(Grant No.2022M720562)Chongqing Postdoctoral Science Foundation(Grant No.2021XM3022)supported by the opening project of State Key Laboratory of Explosion Science and Technology(Beijing Institute of Technology)The opening project number is KFJJ23-18 M。
文摘This study systematically examines the energy dissipation mechanisms and ballistic characteristics of foam sandwich panels(FSP)under high-velocity impact using the explicit non-linear finite element method.Based on the geometric topology of the FSP system,three FSP configurations with the same areal density are derived,namely multi-layer,gradient core and asymmetric face sheet,and three key structural parameters are identified:core thickness(t_(c)),face sheet thickness(t_(f))and overlap face/core number(n_(o)).The ballistic performance of the FSP system is comprehensively evaluated in terms of the ballistic limit velocity(BLV),deformation modes,energy dissipation mechanism,and specific penetration energy(SPE).The results show that the FSP system exhibits a significant configuration dependence,whose ballistic performance ranking is:asymmetric face sheet>gradient core>multi-layer.The mass distribution of the top and bottom face sheets plays a critical role in the ballistic resistance of the FSP system.Both BLV and SPE increase with tf,while the raising tcor noleads to an increase in BLV but a decrease in SPE.Further,a face-core synchronous enhancement mechanism is discovered by the energy dissipation analysis,based on which the ballistic optimization procedure is also conducted and a design chart is established.This study shed light on the anti-penetration mechanism of the FSP system and might provide a theoretical basis for its engineering application.
文摘针对太阳能电池表面存在的各种缺陷严重影响能量转换效率的问题,提出一种基于改进YOLO11的高效多尺度特征学习模型(efficient multi-scale feature learning based on YOLO11,YOLO11-EMFL),专门用于快速准确地检测太阳能电池中的表面缺陷。该模型在骨干和颈部网络中引入小波卷积以增加感受野,同时将可变形注意力机制引入骨干网络中,以增强对不同图像大小和图像内容的适应能力。此外,在颈部网络中加入特征融合层以增强多尺度特征融合能力,并在小目标检测层引入三重注意力机制以提高对小目标的检测精度。这些改进使得YOLO11-EMFL网络能够有效地应对不同缺陷种类、缺陷尺寸以及复杂背景的挑战。通过在大规模光伏电池图像数据集上的验证,实验结果显示,YOLO11-EMFL的精确率达到91.8%,召回率为93.8%,F1分数为92.0%,mAP@50和mAP@50-95分别为98.2%和76.9%,在12种缺陷上展现出极高的检测精度。与当前的其他方法相比,该模型的各方面性能都有提升。
