Electrostrictive materials have wide applications in modern high-precision electronic devices.Driven by growing environmental concerns,there is demand for lead-free materials with superior electrostriction behaviors.I...Electrostrictive materials have wide applications in modern high-precision electronic devices.Driven by growing environmental concerns,there is demand for lead-free materials with superior electrostriction behaviors.In this study,we demonstrate a record-high electrostrictive coefficient of~0.0712 m^(4) C^(-2) in perovskite ferroelectric ceramics,along with hysteresis-free strain as well as excellent frequency and thermal stabilities,in lead-free BaTiO_(3)-based ceramics through a polarization nanocluster design.By appro-priately introducing Li+and Bi^(3+)into the BaTiO 3 lattice matrix,the long-range ferroelectric ordering can be broken,and polarization nanoclusters can be formed,resulting in a relaxor state with concurrently suppressed polariza-tion and maintained electro-strain.A three-dimensional atomic model constructed using advanced neutron total-scattering data combined with the reverse Monte Carlo method indicates the existence of Bi and Li segregations at the subnanometer scale,which confirms the prediction made by density functional theory calculations.Such a short-range chemical order destroys the long-range ferroelectric order of the off-centered Ti polar displacements and leads to the embedding of Li+/Bi ^(3+)-rich polar nanoregions in the Ba^(2+)-rich polarization disorder matrix.Further,a completely reversible electric-field-induced lattice strain is observed,giving rise to pure electrostriction without hysteresis behavior.This work provides a novel strategy for developing lead-free relaxor ferroelectrics with high electrostriction performance.展开更多
Due to the coronavirus disease 2019(COVID‐19)pandemic,the development of antiviral drugs has attracted increasing attention.Clinical antiviral drugs show weak solubility,low bioavailability,adverse side effects,or on...Due to the coronavirus disease 2019(COVID‐19)pandemic,the development of antiviral drugs has attracted increasing attention.Clinical antiviral drugs show weak solubility,low bioavailability,adverse side effects,or only limited targets.With the advancement of nanotechnology and material science,biosafety nanomaterials have been constructed for drug delivery systems of antiviral disease therapy,such as liposomes,polymers,gold nanoparticles,and graphene.These nanodrug systems can either deliver synthesized antiviral drugs siRNA/miRNA and small molecular compounds,deliver bioactive large molecular drug proteins and mRNA,or show antiviral activity by themselves.Nanodelivery systems could effectively enhance the efficiency of antiviral drugs by increasing drug loading and host cell uptake with a small size and high specific surface area.This review focused on the biosafety nanomaterials used for antiviral therapy and discussed the options for the design of antiviral drugs in the future.展开更多
基金This work was supported by the National Natural Science Foundation of China(grant nos.21825102,and 22075014)the Fundamental Research Funds for the Central Univer-sities,China(FRF-MP-20-40)+1 种基金National Postdoctoral Program for Innovative Talents(BX20200044,and BX20200043)the State Key Lab of Advanced Metals and Materials(2020-ZD01)。
文摘Electrostrictive materials have wide applications in modern high-precision electronic devices.Driven by growing environmental concerns,there is demand for lead-free materials with superior electrostriction behaviors.In this study,we demonstrate a record-high electrostrictive coefficient of~0.0712 m^(4) C^(-2) in perovskite ferroelectric ceramics,along with hysteresis-free strain as well as excellent frequency and thermal stabilities,in lead-free BaTiO_(3)-based ceramics through a polarization nanocluster design.By appro-priately introducing Li+and Bi^(3+)into the BaTiO 3 lattice matrix,the long-range ferroelectric ordering can be broken,and polarization nanoclusters can be formed,resulting in a relaxor state with concurrently suppressed polariza-tion and maintained electro-strain.A three-dimensional atomic model constructed using advanced neutron total-scattering data combined with the reverse Monte Carlo method indicates the existence of Bi and Li segregations at the subnanometer scale,which confirms the prediction made by density functional theory calculations.Such a short-range chemical order destroys the long-range ferroelectric order of the off-centered Ti polar displacements and leads to the embedding of Li+/Bi ^(3+)-rich polar nanoregions in the Ba^(2+)-rich polarization disorder matrix.Further,a completely reversible electric-field-induced lattice strain is observed,giving rise to pure electrostriction without hysteresis behavior.This work provides a novel strategy for developing lead-free relaxor ferroelectrics with high electrostriction performance.
基金supported by the National Key Research&Development Program of China(No.2021YFA1201000)the Government Guided Local Science and Technology Development Fund Projects of Hebei Province(No.216Z2403G)+2 种基金Natural Science Foundation of Hebei Province(No.B2019201449,H2019201466)the Priority Strategy Project of the Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of the Ministry of Education(ts2020003)the Hebei Province“Three Three Three Talents Program”(A202003001).
文摘Due to the coronavirus disease 2019(COVID‐19)pandemic,the development of antiviral drugs has attracted increasing attention.Clinical antiviral drugs show weak solubility,low bioavailability,adverse side effects,or only limited targets.With the advancement of nanotechnology and material science,biosafety nanomaterials have been constructed for drug delivery systems of antiviral disease therapy,such as liposomes,polymers,gold nanoparticles,and graphene.These nanodrug systems can either deliver synthesized antiviral drugs siRNA/miRNA and small molecular compounds,deliver bioactive large molecular drug proteins and mRNA,or show antiviral activity by themselves.Nanodelivery systems could effectively enhance the efficiency of antiviral drugs by increasing drug loading and host cell uptake with a small size and high specific surface area.This review focused on the biosafety nanomaterials used for antiviral therapy and discussed the options for the design of antiviral drugs in the future.