Understanding the complex plasma dynamics in ultra-intense relativistic laser-solid interactions is of fundamental importance for applications of laser-plasma-based particle accelerators,the creation of high-energy-de...Understanding the complex plasma dynamics in ultra-intense relativistic laser-solid interactions is of fundamental importance for applications of laser-plasma-based particle accelerators,the creation of high-energy-density matter,understanding planetary science,and laser-driven fusion energy.However,experimental efforts in this regime have been limited by the lack of accessibility of over-critical densities and the poor spatiotemporal resolution of conventional diagnostics.Over the last decade,the advent of femtosecond brilliant hard X-ray free-electron lasers(XFELs)has opened new horizons to overcome these limitations.Here,for the first time,we present full-scale spatiotemporal measurements of solid-density plasma dynamics,including preplasma generation with tens of nanometer scale length driven by the leading edge of a relativistic laser pulse,ultrafast heating and ionization at the main pulse arrival,the laser-driven blast wave,and transient surface return current-induced compression dynamics up to hundreds of picoseconds after interaction.These observations are enabled by utilizing a novel combination of advanced X-ray diagnostics including small-angle X-ray scattering,resonant X-ray emission spectroscopy,and propagation-based X-ray phase-contrast imaging simultaneously at the European XFEL-HED beamline station.展开更多
Biodegradable magnesium(Mg)alloys can revolutionize osteosynthesis,because they have mechanical properties similar to those of the bone,and degrade over time,avoiding the need of removal surgery.However,they are not y...Biodegradable magnesium(Mg)alloys can revolutionize osteosynthesis,because they have mechanical properties similar to those of the bone,and degrade over time,avoiding the need of removal surgery.However,they are not yet routinely applied because their degradation behavior is not fully understood.In this study we have investigated and quantified the degradation and osseointegration behavior of two biodegradable Mg alloys based on gadolinium(Gd)at high resolution.Mg-5Gd and Mg-10Gd screws were inserted in rat tibia for 4,8 and 12 weeks.Afterward,the degradation rate and degradation homogeneity,as well as bone-to-implant interface,were studied with synchrotron radiation micro computed tomography and histology.Titanium(Ti)and polyether ether ketone(PEEK)were used as controls material to evaluate osseointegration.Our results showed that Mg-5Gd degraded faster and less homogeneously than Mg-10Gd.Both alloys gradually form a stable degradation layer at the interface and were surrounded by new bone tissue.The results were correlated to in vitro data obtained from the same material and shape.The average bone-to-implant contact of the Mg-xGd implants was comparable to that of Ti and higher than for PEEK.The results suggest that both Mg-xGd alloys are suitable as materials for bone implants.展开更多
基金partially supported by the Helmholtz Imaging platform through the project“SmartPhase.”。
文摘Understanding the complex plasma dynamics in ultra-intense relativistic laser-solid interactions is of fundamental importance for applications of laser-plasma-based particle accelerators,the creation of high-energy-density matter,understanding planetary science,and laser-driven fusion energy.However,experimental efforts in this regime have been limited by the lack of accessibility of over-critical densities and the poor spatiotemporal resolution of conventional diagnostics.Over the last decade,the advent of femtosecond brilliant hard X-ray free-electron lasers(XFELs)has opened new horizons to overcome these limitations.Here,for the first time,we present full-scale spatiotemporal measurements of solid-density plasma dynamics,including preplasma generation with tens of nanometer scale length driven by the leading edge of a relativistic laser pulse,ultrafast heating and ionization at the main pulse arrival,the laser-driven blast wave,and transient surface return current-induced compression dynamics up to hundreds of picoseconds after interaction.These observations are enabled by utilizing a novel combination of advanced X-ray diagnostics including small-angle X-ray scattering,resonant X-ray emission spectroscopy,and propagation-based X-ray phase-contrast imaging simultaneously at the European XFEL-HED beamline station.
基金This research was carried out within the SynchroLoad project(BMBF project number 05K16CGA)which is funded by the Rontgen-Ångstrom Cluster(RÅC)a bilateral research collaboration of the Swedish government and the German Federal Ministry of Education and Research(BMBF)+1 种基金We also acknowledge the project MgBone(BMBF project number 05K16CGB)Swedish Research Council 2015-06109.Additionally,we acknowledge provision of beamtime by PETRA III DESY within the long-term Proposal II-20170009 and beamtimes related to following IDs:11001978,11003288,11003440,11003773,11003950,11004016,11004263,11005553,and 11005842。
文摘Biodegradable magnesium(Mg)alloys can revolutionize osteosynthesis,because they have mechanical properties similar to those of the bone,and degrade over time,avoiding the need of removal surgery.However,they are not yet routinely applied because their degradation behavior is not fully understood.In this study we have investigated and quantified the degradation and osseointegration behavior of two biodegradable Mg alloys based on gadolinium(Gd)at high resolution.Mg-5Gd and Mg-10Gd screws were inserted in rat tibia for 4,8 and 12 weeks.Afterward,the degradation rate and degradation homogeneity,as well as bone-to-implant interface,were studied with synchrotron radiation micro computed tomography and histology.Titanium(Ti)and polyether ether ketone(PEEK)were used as controls material to evaluate osseointegration.Our results showed that Mg-5Gd degraded faster and less homogeneously than Mg-10Gd.Both alloys gradually form a stable degradation layer at the interface and were surrounded by new bone tissue.The results were correlated to in vitro data obtained from the same material and shape.The average bone-to-implant contact of the Mg-xGd implants was comparable to that of Ti and higher than for PEEK.The results suggest that both Mg-xGd alloys are suitable as materials for bone implants.
