Magnesium and its alloy have good mechanical properties and biodegradability,and have become the hotspot of the next-generation biodegradable vascular stent materials.However,their rapid degradation in vivo and poor b...Magnesium and its alloy have good mechanical properties and biodegradability,and have become the hotspot of the next-generation biodegradable vascular stent materials.However,their rapid degradation in vivo and poor biocompatibility are still the bottlenecks of clinical applications for the cardiovascular stents.In particular,how to induce the repair and regeneration of the vascular endothelial with normal physiological functions on the surface of the magnesium alloy stent materials represents the key to its clinical application in the field of cardiovascular stents.It has been believed that it is an ideal way to completely solve the postoperative complications through constructing the multifunctional anti-corrosive bioactive coating on the magnesium alloy surface to induce the formation of vascular endothelium with normal physiological functions.However,how to construct a corrosion-resistant multifunctional bioactive coating with the good endothelial regeneration abilities on the magnesium alloy surface still faces a great challenge.This paper mainly focused on highlighting and summarizing the recent advances in the surface endothelialization of the magnesium alloy materials for the vascular stent,including the bio-inert coating,in-situ immobilization of bioactive molecules on the surface,polymer coating loaded with bioactive factors,novel multifunctional polymer coating,bioactive micropatterns,bioactive layer with glycocalyx-like structure,NO-releasing coating and bioactive sol-gel coating.The advantages and disadvantages of these strategies were discussed and analyzed.Finally,in the senses of future development and clinical application,this paper analyzed and summarized the development direction and prospect of surface endothelialization of the magnesium alloy vascular stents.It is anticipated that this review can give the new cues to the surface endothelialization of the cardiovascular magnesium alloy stents and promote future advancements in this field.展开更多
Due to the influence of scatterers around the receiving antenna, the multipath signal in satellite mobile communication systems is correlated with each other which would influence the system performance. There is no s...Due to the influence of scatterers around the receiving antenna, the multipath signal in satellite mobile communication systems is correlated with each other which would influence the system performance. There is no systematic standard on the channel modelling of the wideband satellite channel at present, so the study of the modelling of the wideband satellite channel is of great importance. In this paper, firstly we created a multi-beam model which can figure out the antenna gain of the nth component beam. Secondly, we combined the characteristics of multi-beam satellite channel and the distribution of the scatterers, and set up a three-dimension random channel model. This model is more realistic for satellite communication system since it considers the height of scatterers. According to the channel models, we had the formula of spatial correlation coefficient. We used the formula to calculate the relationship between spatial correlation coefficient and the interval of antennas. The result shows that the spatial correlation exists and cannot be ignored while modeling for mobile satellite system.展开更多
Multiple-Input Multiple-Output (MIMO) technology is widely applied in terrestrial wireless communication system, which greatly increases the system capacity. Satellite communication system has many advantages such as ...Multiple-Input Multiple-Output (MIMO) technology is widely applied in terrestrial wireless communication system, which greatly increases the system capacity. Satellite communication system has many advantages such as wide coverage and strong flexibility. Therefore, how to make a better use of MIMO technology in satellite communication system has become a research hotspot in recent years. The purpose of this paper is to analysis the relationship between satellite MIMO system capacity and parameters of terrestrial antenna such as angle and distance. The parameters of terrestrial antenna were derived and calculated to keep a higher capacity for satellite MIMO system. Numerical analysis of system capacity performance before and after optimization was obtained, which proved the correctness of the theory proposed in this paper.展开更多
The full E-field control of multiferroic interfacial magnetism is a long-standing challenge for micro-electromechanical systems(MEMS)and has the potential to transform electronics operation mechanisms.When scaling dow...The full E-field control of multiferroic interfacial magnetism is a long-standing challenge for micro-electromechanical systems(MEMS)and has the potential to transform electronics operation mechanisms.When scaling down conventional complementary metal-oxide semiconductor(CMOS)devices,increased heating dissipation becomes a top concern.Combining the highly correlated ferroic orders,notably the strongly coupled interfacial magnetoelectric(ME)interactions,may lead to devices beyond CMOS.These devices use the electric field to regulate magnetization,which opens up the prospect of downsizing,improved performance,and lower power consumption.To broadly survey this tremendous scope within the last five years,this review summarizes advances in voltage control of interfacial magnetism(VCIM)with various material system selection;controlling effects with different gating methods are also explored.Five classic mechanisms are demonstrated:strain,exchange bias,orbital reconstruction,and the electrostatic and electrochemical.The encouraging photovoltaic approach is also discussed.Each method’s capabilities and application scenarios are compared.Analyses of the comprehensive gating results of different magnetic coupling effects such as perpendicular magnetic anisotropy(PMA)and Ruderman-Kittel-Kasuya-Yosida(RKKY)are additionally made.At last,controlling of skyrmions and two-dimensional(2D)material magnetization is summarized,indicating that E-field gating offers a universal approach with few limitations for material selection.These results point to potential for E-field control interfacial magnetism and predict significant future advancements for spintronics.展开更多
Electric field(E-field)control of magnetism based on magnetoelectric coupling is one of the promising approaches for manipulating the magnetization with low power consumption.The evolution of magnetic domains under in...Electric field(E-field)control of magnetism based on magnetoelectric coupling is one of the promising approaches for manipulating the magnetization with low power consumption.The evolution of magnetic domains under in-situ E-fields is significant for the practical applications in integrated micro/nano devices.Here,we report the vector analysis of the E-field-driven antiparallel magnetic domain evolution in FeCoSiB/PMN-PT(011)multiferroic heterostructures via in-situ quantitative magneto-optical Kerr microscope.It is demonstrated that the magnetic domains can be switched to both the 0°and 180°easy directions at the same time by E-fields,resulting in antiparallel magnetization distribution in ferromagnetic/ferroelectric heterostructures.This antiparallel magnetic domain evolution is attributed to energy minimization with the uniaxial strains by E-fields which can induce the rotation of domains no more than 90°.Moreover,domains can be driven along only one or both easy axis directions by reasonably selecting the initial magnetic domain distribution.The vector analysis of magnetic domain evolution can provide visual insights into the strain-mediated magnetoelectric effect,and promote the fundamental understanding of electrical regulation of magnetism.展开更多
基金financially supported by the National Natural Science Foundation of China(31870952)Natural Science Foundation of Jiangsu Province of China(BK20181480)。
文摘Magnesium and its alloy have good mechanical properties and biodegradability,and have become the hotspot of the next-generation biodegradable vascular stent materials.However,their rapid degradation in vivo and poor biocompatibility are still the bottlenecks of clinical applications for the cardiovascular stents.In particular,how to induce the repair and regeneration of the vascular endothelial with normal physiological functions on the surface of the magnesium alloy stent materials represents the key to its clinical application in the field of cardiovascular stents.It has been believed that it is an ideal way to completely solve the postoperative complications through constructing the multifunctional anti-corrosive bioactive coating on the magnesium alloy surface to induce the formation of vascular endothelium with normal physiological functions.However,how to construct a corrosion-resistant multifunctional bioactive coating with the good endothelial regeneration abilities on the magnesium alloy surface still faces a great challenge.This paper mainly focused on highlighting and summarizing the recent advances in the surface endothelialization of the magnesium alloy materials for the vascular stent,including the bio-inert coating,in-situ immobilization of bioactive molecules on the surface,polymer coating loaded with bioactive factors,novel multifunctional polymer coating,bioactive micropatterns,bioactive layer with glycocalyx-like structure,NO-releasing coating and bioactive sol-gel coating.The advantages and disadvantages of these strategies were discussed and analyzed.Finally,in the senses of future development and clinical application,this paper analyzed and summarized the development direction and prospect of surface endothelialization of the magnesium alloy vascular stents.It is anticipated that this review can give the new cues to the surface endothelialization of the cardiovascular magnesium alloy stents and promote future advancements in this field.
文摘Due to the influence of scatterers around the receiving antenna, the multipath signal in satellite mobile communication systems is correlated with each other which would influence the system performance. There is no systematic standard on the channel modelling of the wideband satellite channel at present, so the study of the modelling of the wideband satellite channel is of great importance. In this paper, firstly we created a multi-beam model which can figure out the antenna gain of the nth component beam. Secondly, we combined the characteristics of multi-beam satellite channel and the distribution of the scatterers, and set up a three-dimension random channel model. This model is more realistic for satellite communication system since it considers the height of scatterers. According to the channel models, we had the formula of spatial correlation coefficient. We used the formula to calculate the relationship between spatial correlation coefficient and the interval of antennas. The result shows that the spatial correlation exists and cannot be ignored while modeling for mobile satellite system.
文摘Multiple-Input Multiple-Output (MIMO) technology is widely applied in terrestrial wireless communication system, which greatly increases the system capacity. Satellite communication system has many advantages such as wide coverage and strong flexibility. Therefore, how to make a better use of MIMO technology in satellite communication system has become a research hotspot in recent years. The purpose of this paper is to analysis the relationship between satellite MIMO system capacity and parameters of terrestrial antenna such as angle and distance. The parameters of terrestrial antenna were derived and calculated to keep a higher capacity for satellite MIMO system. Numerical analysis of system capacity performance before and after optimization was obtained, which proved the correctness of the theory proposed in this paper.
基金supported by the National Key Research and Development Program of China(Nos.2018YFB0407601 and 2019YFA0307900)the National Natural Science Foundation of China(Nos.91964109 and 51972028)the National 111 Project of China(No.B14040),and the Key Research and Developmen Program of Shaanxi(No.2019TSLG).
文摘The full E-field control of multiferroic interfacial magnetism is a long-standing challenge for micro-electromechanical systems(MEMS)and has the potential to transform electronics operation mechanisms.When scaling down conventional complementary metal-oxide semiconductor(CMOS)devices,increased heating dissipation becomes a top concern.Combining the highly correlated ferroic orders,notably the strongly coupled interfacial magnetoelectric(ME)interactions,may lead to devices beyond CMOS.These devices use the electric field to regulate magnetization,which opens up the prospect of downsizing,improved performance,and lower power consumption.To broadly survey this tremendous scope within the last five years,this review summarizes advances in voltage control of interfacial magnetism(VCIM)with various material system selection;controlling effects with different gating methods are also explored.Five classic mechanisms are demonstrated:strain,exchange bias,orbital reconstruction,and the electrostatic and electrochemical.The encouraging photovoltaic approach is also discussed.Each method’s capabilities and application scenarios are compared.Analyses of the comprehensive gating results of different magnetic coupling effects such as perpendicular magnetic anisotropy(PMA)and Ruderman-Kittel-Kasuya-Yosida(RKKY)are additionally made.At last,controlling of skyrmions and two-dimensional(2D)material magnetization is summarized,indicating that E-field gating offers a universal approach with few limitations for material selection.These results point to potential for E-field control interfacial magnetism and predict significant future advancements for spintronics.
基金supported by the National Key R&D Program of China(2018YFB0407601)the National Natural Science Foundation of China(91964109,62071374 and 51802248)the National 111 Project of China(B14040).
基金supported by the National Key R&D Program of China(Grant No.2018YFB0407601)the National Natural Science Foundation of China(Grant Nos.91964109,62071374,and 51802248)+1 种基金the National 111 Project of China(Grant No.B14040)the Fundamental Research Funds for the Central Universities(Grant No.xxj022020008).
文摘Electric field(E-field)control of magnetism based on magnetoelectric coupling is one of the promising approaches for manipulating the magnetization with low power consumption.The evolution of magnetic domains under in-situ E-fields is significant for the practical applications in integrated micro/nano devices.Here,we report the vector analysis of the E-field-driven antiparallel magnetic domain evolution in FeCoSiB/PMN-PT(011)multiferroic heterostructures via in-situ quantitative magneto-optical Kerr microscope.It is demonstrated that the magnetic domains can be switched to both the 0°and 180°easy directions at the same time by E-fields,resulting in antiparallel magnetization distribution in ferromagnetic/ferroelectric heterostructures.This antiparallel magnetic domain evolution is attributed to energy minimization with the uniaxial strains by E-fields which can induce the rotation of domains no more than 90°.Moreover,domains can be driven along only one or both easy axis directions by reasonably selecting the initial magnetic domain distribution.The vector analysis of magnetic domain evolution can provide visual insights into the strain-mediated magnetoelectric effect,and promote the fundamental understanding of electrical regulation of magnetism.
