It is challenging to match the mutual interactions between implant and host because the biomaterials usually cannot actively adjust their performance to the changing microenvironment.Surface potential is one of the cr...It is challenging to match the mutual interactions between implant and host because the biomaterials usually cannot actively adjust their performance to the changing microenvironment.Surface potential is one of the critical factors affecting the bioactivity of biomaterials,but it is difficult to be directly controlled in vivo.Magnetic stimulation has attracted much attention due to its deep penetrability,good reliability,and convenient operability.Here,titanium dioxide(TiO_(2))nanotubes and Terfenol‐D/P(VDF‐TrFE)composite film are prepared by anodic oxidation and solution casting methods on opposite sides of a titanium sheet,respectively.Terfenol‐D magnetostrictive microparticles deform under a magnetic field,generating surface potential on the P(VDF‐TrFE)piezoelectric matrix through magneto‐electric coupling.Correspondingly,equal opposite charges are induced on the surface of TiO_(2) nanotubes.Stem cells cultured on TiO_(2) nanotubes show that cell adhesion,proliferation,and differentiation abilities can be regulated by magnetic strength,which correlates with the absorption of charged proteins.Therefore,a cascade coupling of magnetic,mechanical,electric,biochemical,and cellular effects is established.This work demonstrates the feasibility of regulating the bioactivity of biomaterials in vivo through a magnetic field.展开更多
X-ray pulsar-based navigation is a revolutionary technology which is capable of providing the required navigation information in the solar system. Performing as an important pulsar-based navigation technique, the Sign...X-ray pulsar-based navigation is a revolutionary technology which is capable of providing the required navigation information in the solar system. Performing as an important pulsar-based navigation technique, the Significance Enhancement of Pulse-profile with Orbit-dynamics(SEPO)can estimate orbital elements by using the distortion of pulse profile. Based on the SEPO technique,we propose a grouping bi-chi-squared technique and adopt the observations of Rossi X-ray Timing Explorer(RXTE) to carry out experimental verification. The pulsar timing is refined to determine spin parameters of the Crab pulsar(PSR B0531+21) during the observation periods, and a short-term dynamic model for RXTE satellite is established by considering the effects of diverse perturbations.Experimental results suggest that the position and velocity errors are 16.3 km(3σ) and 13.3 m/s(3σ) with two adjacent observations split by one day(exposure time of 1.5 ks), outperforming those of the POLAR experiment whose results are 19.2 km(3σ) and 432 m/s(3σ). The approach provided is particularly applicable to the estimation of orbital elements via using high-flux observations.展开更多
基金Guangdong Basic and Applied Basic Research Foundation,Grant/Award Numbers:2021B1515120019,2019A1515011891,2015A030312004Science and Technology Projects in Guangzhou,Grant/Award Number:202102020644Opening Project of Guangdong Provincial Key Laboratory of Technique and Equipment for Macromolecular Advanced Manufacturing,Grant/Award Number:2019kfkt01。
文摘It is challenging to match the mutual interactions between implant and host because the biomaterials usually cannot actively adjust their performance to the changing microenvironment.Surface potential is one of the critical factors affecting the bioactivity of biomaterials,but it is difficult to be directly controlled in vivo.Magnetic stimulation has attracted much attention due to its deep penetrability,good reliability,and convenient operability.Here,titanium dioxide(TiO_(2))nanotubes and Terfenol‐D/P(VDF‐TrFE)composite film are prepared by anodic oxidation and solution casting methods on opposite sides of a titanium sheet,respectively.Terfenol‐D magnetostrictive microparticles deform under a magnetic field,generating surface potential on the P(VDF‐TrFE)piezoelectric matrix through magneto‐electric coupling.Correspondingly,equal opposite charges are induced on the surface of TiO_(2) nanotubes.Stem cells cultured on TiO_(2) nanotubes show that cell adhesion,proliferation,and differentiation abilities can be regulated by magnetic strength,which correlates with the absorption of charged proteins.Therefore,a cascade coupling of magnetic,mechanical,electric,biochemical,and cellular effects is established.This work demonstrates the feasibility of regulating the bioactivity of biomaterials in vivo through a magnetic field.
基金the National Natural Science Foundation of China(No.62103313)the Space Optoelectronic Measurement&Perception Laboratory of BICE,China(No.LabSOMP-2020-06)the Central Universities,China(No.JC2007).
文摘X-ray pulsar-based navigation is a revolutionary technology which is capable of providing the required navigation information in the solar system. Performing as an important pulsar-based navigation technique, the Significance Enhancement of Pulse-profile with Orbit-dynamics(SEPO)can estimate orbital elements by using the distortion of pulse profile. Based on the SEPO technique,we propose a grouping bi-chi-squared technique and adopt the observations of Rossi X-ray Timing Explorer(RXTE) to carry out experimental verification. The pulsar timing is refined to determine spin parameters of the Crab pulsar(PSR B0531+21) during the observation periods, and a short-term dynamic model for RXTE satellite is established by considering the effects of diverse perturbations.Experimental results suggest that the position and velocity errors are 16.3 km(3σ) and 13.3 m/s(3σ) with two adjacent observations split by one day(exposure time of 1.5 ks), outperforming those of the POLAR experiment whose results are 19.2 km(3σ) and 432 m/s(3σ). The approach provided is particularly applicable to the estimation of orbital elements via using high-flux observations.
