Power cables are important pieces of equipment for energy transmission,but achieving a good balance between flame retardancy and mechanical properties of cable sheaths remains a challenge.In this work,a novel intumesc...Power cables are important pieces of equipment for energy transmission,but achieving a good balance between flame retardancy and mechanical properties of cable sheaths remains a challenge.In this work,a novel intumescent flame retardant(IFR)system containing silicone-containing macromolecular charring agent(Si-MCA)and ammonium polyphosphate(APP)was designed to synergistically improve the flame retardancy and mechanical properties of ethylene-butyl acrylate copolymer(EBA)composites.The optimal mass ratio of APP/Si-MCA was 3/1 in EBA composites(EBA/APP-Si-31),corresponding to the best flame retardancy with 31.2% of limited oxygen index(LOI),V-0 rating in UL-94 vertical burning test,and 76.4%reduction on the peak of heat release rate(PHRR)in cone calorimeter test.The enhancement mechanism was attributed to the synergistic effect of APP/Si-MCA during combustion,including the radical-trapping effect,the dilution effect of non-flammable gases,and the barrier effect of the intumescent char layer.Meanwhile,the tensile results indicated that EBA/APP-Si-31 also exhibited good mechanical properties with the addition of maleic anhydride-grafted polyethylene(PE-g-MA)as the compatibilizer.Thus,the APP/Si-MCA combination is an effective IFRs system for preparing high-performance EBA composites,and it will promote their applications as cable sheath materials.展开更多
With the rapid development of deep resource extraction and underground space construction,the design of anchored support systems for jointed rock masses in complex stress environments faces significant challenges.This...With the rapid development of deep resource extraction and underground space construction,the design of anchored support systems for jointed rock masses in complex stress environments faces significant challenges.This study investigates the influence of prefabricated crack dip angles on the mechanical properties of anchored rock masses in deep soft rock roadways.By constructing similarity models of NPR(Negative Poisson’s Ratio)and PR(Positive Poisson’s Ratio)anchored solids,biaxial compression experiments under varying crack dip angles were conducted.Strain gauges,3D Digital Image Correlation(3D DIC),and acoustic emission monitoring were employed to systematically analyze the strength characteristics,deformation-damage evolution,and energy dissipation mechanisms of the two types of anchor systems.The results show that:(1)The stress-strain curves of anchored solids with prefabricated cracks exhibit a distinct bimodal characteristic.Compared to PR anchors,NPR anchors show 20%and 23%improvements in peak strength and elastic modulus,respectively,with residual strength enhanced by up to 34%.(2)Owing to high pre-tightening force and large deformation capacity,NPR anchors maintain superior integrity under increasing crack dip angles,demonstrating more uniform free-surface displacement and localized shear-tensile composite crack patterns.(3)Acoustic emission analysis reveals that NPR anchors exhibit higher cumulative energy absorption(300%improvement over PR anchors)and lack low-rate energy development phases,indicating enhanced ductility and impact resistance at high crack dip angles.(4)Crack dip angle critically governs failure mechanisms by modulating the connectivity between shear cracks and prefabricated fissures:bimodal effects dominate at low angles,while vertical tensile crack propagation replaces bimodal behavior at high angles.The study proposes prioritizing NPR anchor cables in deep engineering applications and optimizing support parameters based on crack dip angles to mitigate stress concentration and ensure the long-term stability of surrounding rock.展开更多
Glucosinolates are important phytochemicals in Brassicaceae.We investigated the effect of CaCl_(2)-HCl electrolyzed water(CHEW)on glucosinolates biosynthesis in broccoli sprouts.The results showed that CHEW treatment ...Glucosinolates are important phytochemicals in Brassicaceae.We investigated the effect of CaCl_(2)-HCl electrolyzed water(CHEW)on glucosinolates biosynthesis in broccoli sprouts.The results showed that CHEW treatment significantly decreased reactive oxygen species(ROS)and malondialdeh yde(MDA)contents in broccoli sprouts.On the the 8^(th)day,compared to tap water treatment,the the total glucosinolate content of broccoli sprouts with CHEW treatment increased by 10.6%and calcium content was dramatically enhanced from 14.4 mg/g DW to 22.7 mg/g DW.Comparative transcriptome and metabolome analyses revealed that CHEW treatment activated ROS and calcium signaling transduction pathways in broccoli sprouts and they interacted through MAPK cascades.Besides,CHEW treatment not only promoted the biosynthesis of amino acids,but also enhanced the expression of structural genes in glucosinolate synthesis through transcription factors(MYBs,bHLHs,WRKYs,etc.).The results of this study provided new insights into the regulatory network of glucosinolates biosynthesis in broccoli sprouts under CHEW treatment.展开更多
基金supported by the National Natural Science Foundation of China(52473059)Taishan Scholar Constructive Engineering Foundation of Shandong Province(tsqn202103079)Key Research and Development Plan of Shandong Province(2024TSGC0264).
文摘Power cables are important pieces of equipment for energy transmission,but achieving a good balance between flame retardancy and mechanical properties of cable sheaths remains a challenge.In this work,a novel intumescent flame retardant(IFR)system containing silicone-containing macromolecular charring agent(Si-MCA)and ammonium polyphosphate(APP)was designed to synergistically improve the flame retardancy and mechanical properties of ethylene-butyl acrylate copolymer(EBA)composites.The optimal mass ratio of APP/Si-MCA was 3/1 in EBA composites(EBA/APP-Si-31),corresponding to the best flame retardancy with 31.2% of limited oxygen index(LOI),V-0 rating in UL-94 vertical burning test,and 76.4%reduction on the peak of heat release rate(PHRR)in cone calorimeter test.The enhancement mechanism was attributed to the synergistic effect of APP/Si-MCA during combustion,including the radical-trapping effect,the dilution effect of non-flammable gases,and the barrier effect of the intumescent char layer.Meanwhile,the tensile results indicated that EBA/APP-Si-31 also exhibited good mechanical properties with the addition of maleic anhydride-grafted polyethylene(PE-g-MA)as the compatibilizer.Thus,the APP/Si-MCA combination is an effective IFRs system for preparing high-performance EBA composites,and it will promote their applications as cable sheath materials.
基金supported by the National Natural Science Foundation of China(Grant Nos.52174096 and 52304110).
文摘With the rapid development of deep resource extraction and underground space construction,the design of anchored support systems for jointed rock masses in complex stress environments faces significant challenges.This study investigates the influence of prefabricated crack dip angles on the mechanical properties of anchored rock masses in deep soft rock roadways.By constructing similarity models of NPR(Negative Poisson’s Ratio)and PR(Positive Poisson’s Ratio)anchored solids,biaxial compression experiments under varying crack dip angles were conducted.Strain gauges,3D Digital Image Correlation(3D DIC),and acoustic emission monitoring were employed to systematically analyze the strength characteristics,deformation-damage evolution,and energy dissipation mechanisms of the two types of anchor systems.The results show that:(1)The stress-strain curves of anchored solids with prefabricated cracks exhibit a distinct bimodal characteristic.Compared to PR anchors,NPR anchors show 20%and 23%improvements in peak strength and elastic modulus,respectively,with residual strength enhanced by up to 34%.(2)Owing to high pre-tightening force and large deformation capacity,NPR anchors maintain superior integrity under increasing crack dip angles,demonstrating more uniform free-surface displacement and localized shear-tensile composite crack patterns.(3)Acoustic emission analysis reveals that NPR anchors exhibit higher cumulative energy absorption(300%improvement over PR anchors)and lack low-rate energy development phases,indicating enhanced ductility and impact resistance at high crack dip angles.(4)Crack dip angle critically governs failure mechanisms by modulating the connectivity between shear cracks and prefabricated fissures:bimodal effects dominate at low angles,while vertical tensile crack propagation replaces bimodal behavior at high angles.The study proposes prioritizing NPR anchor cables in deep engineering applications and optimizing support parameters based on crack dip angles to mitigate stress concentration and ensure the long-term stability of surrounding rock.
基金supported by the National Natural Science Foundation of China(31972091)。
文摘Glucosinolates are important phytochemicals in Brassicaceae.We investigated the effect of CaCl_(2)-HCl electrolyzed water(CHEW)on glucosinolates biosynthesis in broccoli sprouts.The results showed that CHEW treatment significantly decreased reactive oxygen species(ROS)and malondialdeh yde(MDA)contents in broccoli sprouts.On the the 8^(th)day,compared to tap water treatment,the the total glucosinolate content of broccoli sprouts with CHEW treatment increased by 10.6%and calcium content was dramatically enhanced from 14.4 mg/g DW to 22.7 mg/g DW.Comparative transcriptome and metabolome analyses revealed that CHEW treatment activated ROS and calcium signaling transduction pathways in broccoli sprouts and they interacted through MAPK cascades.Besides,CHEW treatment not only promoted the biosynthesis of amino acids,but also enhanced the expression of structural genes in glucosinolate synthesis through transcription factors(MYBs,bHLHs,WRKYs,etc.).The results of this study provided new insights into the regulatory network of glucosinolates biosynthesis in broccoli sprouts under CHEW treatment.
文摘针对车辆检测领域中现有的小目标检测算法面临的复杂度高、特征提取不足以及检测率低的问题,提出了一种改进模型ARR-DETR,旨在提升小目标车辆检测的效率和精度。借助CSP的思想,通过卷积加性自注意力机制(convolutional additive self-attention,CATM)和卷积门控线性单元(gated linear unit,GLU)构建CSP-ADD-CGLU模块,以改进RT-DETR的骨干网络,在降低计算复杂度的同时增强关键特征的提取能力,从而提升模型的表现力和训练稳定性。构建AIFI-RepBN模块,采用渐进重参数化方法,在训练过程中逐渐从LayerNorm过渡到BatchNorm,实现更高效的计算,同时保持模型性能。在融合模块中引入显式空间先验和注意力分解,强化对小目标位置的感知能力,同时提升对不同尺度特征的选择性关注能力,提高模型对小目标的识别精度,还增强了整体特征融合的效果。实验结果表明,改进的RT-DETR模型在BDD100K数据集上的P、Recall和FPS指标分别为74.4%、66.1%和67.4%。与原始RT-DETR模型相比,分别提升了1.6%、2.1%和3.3%,表明该方法可以更快速、更准确地检测到小目标车辆。
