Mg alloys have mechanical properties compatible with human bones.However,their rapid degradation and associated foreign body reactions in vivo significantly limit their application for human implants.In this study,thr...Mg alloys have mechanical properties compatible with human bones.However,their rapid degradation and associated foreign body reactions in vivo significantly limit their application for human implants.In this study,three differently processed Mg alloys,pure Mg(PM),cold extruded Mg alloy AZ31(CE AZ31),and fully annealed AZ31 Mg alloy(FA AZ31)were comparatively investigated for their potential as implants using a rat model.All three implanted Mg alloys do not show any impact on hepato-and renal function,nor any signs of observable changes to vital organs.Proteomics analysis of tissues directly contacting the implants 2.5 months post implantation revealed that FA AZ31 activates very few inflammation and immune associated signaling pathways;while the CE AZ31 and PM produce more significant inflammatory responses as confirmed by cytokine array analyses.Further,FA AZ31 activated pathways for cell organization and development that may improve the recovery of injured tissues.Structurally,EBSD analysis reveals that the FA AZ31 alloy has a higher ratio of first-order pyramidal orientated(10–11){10–1–2}grain texture with a value of 0.25,while PM and CE AZ31 alloys have lower ratios of first-order pyramidal orientated texture with the values of 0.16 and 0.17,respectively.This is associated with recovery and recrystallisation during annealing which promotes grain texture which exhibits enhanced degradation behaviours and induces a more limited immune response in vivo.In conclusion,the FA AZ31 demonstrated better biocompatibility and corrosion resistance and is a promising candidate for metal-based degradable implants which warrants further investigation.展开更多
This paper proposes a stable gain and a compact Antipodal Vivaldi Antenna(AVA)for a 38GHz band of 5G communication.A novel compact AVA is designed to provide constant gain,high front to back ratio(FBR),and very high e...This paper proposes a stable gain and a compact Antipodal Vivaldi Antenna(AVA)for a 38GHz band of 5G communication.A novel compact AVA is designed to provide constant gain,high front to back ratio(FBR),and very high efficiency.The performance of the proposed AVA is enhanced with the help of a dielectric lens(DL)and corrugations.A rectangular-shaped DL is incorporated in conventional AVA(CAVA)to enhance its gain up to 1 dBi and the bandwidth by 1.8 GHz.Next,the rectangular corrugations are implemented in CAVA with lens(CAVA-L)to further improve the gain and bandwidth.The proposed AVA with lens and corrugations(AVA-LC)gives a constant and high gain of 8.2 to 9 dBi.The designed AVA-LC operates from 34 to 45GHz frequency which covers 38GHz(37.5 to 43.5 GHz)band of 5G applications.Further,the presented AVA-LC mitigates the back lobe and sidelobe levels,resulting in FBR and efficiency improvement.The FBR is in the range of 12.2 to 22 dB,and efficiency is 99%,almost constant.The AVA-LC is fabricated on Roger’s RT/duroid 5880 substrate,and it is tested to verify the simulated results.The proposed compact AVA-LC with high gain,an improved FBR,excellent efficiency,and stable radiation patterns is suitable for the 38GHz band of 5G devices.展开更多
为提高压电能量采集(piezoelectric energy harvesting,PEH)系统的转换效率,文章在传统全桥整流器(full-bridge rectifier,FBR)以及同步开关电感收集(synchronous switch harvesting on inductor,SSHI)技术的基础上,设计了冷启动同步开...为提高压电能量采集(piezoelectric energy harvesting,PEH)系统的转换效率,文章在传统全桥整流器(full-bridge rectifier,FBR)以及同步开关电感收集(synchronous switch harvesting on inductor,SSHI)技术的基础上,设计了冷启动同步开关电容收集(synchronous swich harvesting on capacitors,SsHC)整流器.整流器电路可在冷态下提供较高的开路电压,使系统加快进入正常工作状态.内部的开关电容(switched capacitors.SCs)代替电感进行电荷的快速翻转,降低了能量损耗并实现了较高的翻转效率。整流器电路采用TSMC0.18μm CMOS工艺进行搭建与仿真.效率计算结果显示,与传统的全桥整流器相比,在开路电压为4.5 V的情况下,压电能量收集系统的效率提高了5.5倍,超过了大多数SSHI整流器电路,并显著减小了系统面积.仿真结果显示,设计的四电容SSHC整流器的电压翻转效率为66.36%.展开更多
基金supported in part by JSPS research grant(No.P16718)Natural Science Foundation of Guangdong Province(No.2020A1515010855)+2 种基金National Science Foundation of China(31971355)Genecology MCR Seed Funding of University of the Sunshine CoastDeng Feng Project of Foshan First People’s Hospital(2019A008)。
文摘Mg alloys have mechanical properties compatible with human bones.However,their rapid degradation and associated foreign body reactions in vivo significantly limit their application for human implants.In this study,three differently processed Mg alloys,pure Mg(PM),cold extruded Mg alloy AZ31(CE AZ31),and fully annealed AZ31 Mg alloy(FA AZ31)were comparatively investigated for their potential as implants using a rat model.All three implanted Mg alloys do not show any impact on hepato-and renal function,nor any signs of observable changes to vital organs.Proteomics analysis of tissues directly contacting the implants 2.5 months post implantation revealed that FA AZ31 activates very few inflammation and immune associated signaling pathways;while the CE AZ31 and PM produce more significant inflammatory responses as confirmed by cytokine array analyses.Further,FA AZ31 activated pathways for cell organization and development that may improve the recovery of injured tissues.Structurally,EBSD analysis reveals that the FA AZ31 alloy has a higher ratio of first-order pyramidal orientated(10–11){10–1–2}grain texture with a value of 0.25,while PM and CE AZ31 alloys have lower ratios of first-order pyramidal orientated texture with the values of 0.16 and 0.17,respectively.This is associated with recovery and recrystallisation during annealing which promotes grain texture which exhibits enhanced degradation behaviours and induces a more limited immune response in vivo.In conclusion,the FA AZ31 demonstrated better biocompatibility and corrosion resistance and is a promising candidate for metal-based degradable implants which warrants further investigation.
基金This research was funded by Princess Nourah bint Abdulrahman University Researchers Supporting Project number(PNURSP2022R79)Princess Nourah bint Abdulrahman University,Riyadh,Saudi Arabia,S.Urooj,www.pnu.edu.sa.
文摘This paper proposes a stable gain and a compact Antipodal Vivaldi Antenna(AVA)for a 38GHz band of 5G communication.A novel compact AVA is designed to provide constant gain,high front to back ratio(FBR),and very high efficiency.The performance of the proposed AVA is enhanced with the help of a dielectric lens(DL)and corrugations.A rectangular-shaped DL is incorporated in conventional AVA(CAVA)to enhance its gain up to 1 dBi and the bandwidth by 1.8 GHz.Next,the rectangular corrugations are implemented in CAVA with lens(CAVA-L)to further improve the gain and bandwidth.The proposed AVA with lens and corrugations(AVA-LC)gives a constant and high gain of 8.2 to 9 dBi.The designed AVA-LC operates from 34 to 45GHz frequency which covers 38GHz(37.5 to 43.5 GHz)band of 5G applications.Further,the presented AVA-LC mitigates the back lobe and sidelobe levels,resulting in FBR and efficiency improvement.The FBR is in the range of 12.2 to 22 dB,and efficiency is 99%,almost constant.The AVA-LC is fabricated on Roger’s RT/duroid 5880 substrate,and it is tested to verify the simulated results.The proposed compact AVA-LC with high gain,an improved FBR,excellent efficiency,and stable radiation patterns is suitable for the 38GHz band of 5G devices.
文摘为提高压电能量采集(piezoelectric energy harvesting,PEH)系统的转换效率,文章在传统全桥整流器(full-bridge rectifier,FBR)以及同步开关电感收集(synchronous switch harvesting on inductor,SSHI)技术的基础上,设计了冷启动同步开关电容收集(synchronous swich harvesting on capacitors,SsHC)整流器.整流器电路可在冷态下提供较高的开路电压,使系统加快进入正常工作状态.内部的开关电容(switched capacitors.SCs)代替电感进行电荷的快速翻转,降低了能量损耗并实现了较高的翻转效率。整流器电路采用TSMC0.18μm CMOS工艺进行搭建与仿真.效率计算结果显示,与传统的全桥整流器相比,在开路电压为4.5 V的情况下,压电能量收集系统的效率提高了5.5倍,超过了大多数SSHI整流器电路,并显著减小了系统面积.仿真结果显示,设计的四电容SSHC整流器的电压翻转效率为66.36%.
