Far-field wireless power transfer(WPT)is a major breakthrough technology that will enable the many anticipated ubiquitous Internet of Things(IoT)applications associated with fifth generation(5G),sixth generation(6G),a...Far-field wireless power transfer(WPT)is a major breakthrough technology that will enable the many anticipated ubiquitous Internet of Things(IoT)applications associated with fifth generation(5G),sixth generation(6G),and beyond wireless ecosystems.Rectennas,which are the combination of rectifying circuits and antennas,are the most critical components in far-field WPT systems.However,compact application devices require even smaller integrated rectennas that simultaneously have large electromagnetic wave capture capabilities,high alternating current(AC)-to-direct current(DC)(AC-to-DC)conversion efficiencies,and facilitate a multifunctional wireless performance.This paper reviews various rectenna miniaturization techniques such as meandered planar inverted-F antenna(PIFA)rectennas;miniaturized monopole-and dipole-based rectennas;fractal loop and patch rectennas;dielectric-loaded rectennas;and electrically small near-field resonant parasitic rectennas.Their performance characteristics are summarized and then compared with our previously developed electrically small Huygens rectennas that are proven to be more suitable for IoT applications.They have been tailored,for example,to achieve batteryfree IoT sensors as is demonstrated in this paper.Battery-free,wirelessly powered devices are smaller and lighter in weight in comparison to battery-powered devices.Moreover,they are environmentally friendly and,hence,have a significant societal benefit.A series of high-performance electrically small Huygens rectennas are presented including Huygens linearly-polarized(HLP)and circularly-polarized(HCP)rectennas;wirelessly powered IoT sensors based on these designs;and a dual-functional HLP rectenna and antenna system.Finally,two linear uniform HLP rectenna array systems are considered for significantly larger wireless power capture.Example arrays illustrate how they can be integrated advantageously with DC or radio frequency(RF)power-combining schemes for practical IoT applications.展开更多
目的观察心形减张缝合术在瘢痕子宫腹部切口愈合中的应用效果。方法选取2019年6月至2020年12月本院收治的需行剖宫产术分娩的瘢痕子宫患者72例,按照双目随机盲选法分为实验组和对照组,各36例。对照组给予常规间断缝合术缝合,实验组给予...目的观察心形减张缝合术在瘢痕子宫腹部切口愈合中的应用效果。方法选取2019年6月至2020年12月本院收治的需行剖宫产术分娩的瘢痕子宫患者72例,按照双目随机盲选法分为实验组和对照组,各36例。对照组给予常规间断缝合术缝合,实验组给予心形减张缝合术缝合。观察两组患者切口愈合时间、缝合时间、疼痛指数及不良反应发生情况。结果实验组切口愈合时间(8.41±1.89)d、缝合时间(5.62±0.91)min均短于对照组(P<0.05),术后24 h VAS评分(3.19±1.22)分低于对照组(P<0.05)。实验组不良反应发生率为5.6%,明显低于对照组的22.2%(P<0.05)。结论心形减张缝合术可促进瘢痕子宫患者腹部切口愈合,且术后不良反应发生率较低,值得临床推广应用。展开更多
基金supported by the University of Technology Sydney (UTS) Chancellor’s Postdoctoral Fellowship (PRO18-6147)Australian Research Council (ARC) Discovery Early Career Researcher Award (DECRA) (PRO20-9959)
文摘Far-field wireless power transfer(WPT)is a major breakthrough technology that will enable the many anticipated ubiquitous Internet of Things(IoT)applications associated with fifth generation(5G),sixth generation(6G),and beyond wireless ecosystems.Rectennas,which are the combination of rectifying circuits and antennas,are the most critical components in far-field WPT systems.However,compact application devices require even smaller integrated rectennas that simultaneously have large electromagnetic wave capture capabilities,high alternating current(AC)-to-direct current(DC)(AC-to-DC)conversion efficiencies,and facilitate a multifunctional wireless performance.This paper reviews various rectenna miniaturization techniques such as meandered planar inverted-F antenna(PIFA)rectennas;miniaturized monopole-and dipole-based rectennas;fractal loop and patch rectennas;dielectric-loaded rectennas;and electrically small near-field resonant parasitic rectennas.Their performance characteristics are summarized and then compared with our previously developed electrically small Huygens rectennas that are proven to be more suitable for IoT applications.They have been tailored,for example,to achieve batteryfree IoT sensors as is demonstrated in this paper.Battery-free,wirelessly powered devices are smaller and lighter in weight in comparison to battery-powered devices.Moreover,they are environmentally friendly and,hence,have a significant societal benefit.A series of high-performance electrically small Huygens rectennas are presented including Huygens linearly-polarized(HLP)and circularly-polarized(HCP)rectennas;wirelessly powered IoT sensors based on these designs;and a dual-functional HLP rectenna and antenna system.Finally,two linear uniform HLP rectenna array systems are considered for significantly larger wireless power capture.Example arrays illustrate how they can be integrated advantageously with DC or radio frequency(RF)power-combining schemes for practical IoT applications.
文摘目的观察心形减张缝合术在瘢痕子宫腹部切口愈合中的应用效果。方法选取2019年6月至2020年12月本院收治的需行剖宫产术分娩的瘢痕子宫患者72例,按照双目随机盲选法分为实验组和对照组,各36例。对照组给予常规间断缝合术缝合,实验组给予心形减张缝合术缝合。观察两组患者切口愈合时间、缝合时间、疼痛指数及不良反应发生情况。结果实验组切口愈合时间(8.41±1.89)d、缝合时间(5.62±0.91)min均短于对照组(P<0.05),术后24 h VAS评分(3.19±1.22)分低于对照组(P<0.05)。实验组不良反应发生率为5.6%,明显低于对照组的22.2%(P<0.05)。结论心形减张缝合术可促进瘢痕子宫患者腹部切口愈合,且术后不良反应发生率较低,值得临床推广应用。
