In the work, we studied the effect of the plasma of a runaway electron preionized （REP） diffuse discharge （DD） on the composition, structure, and properties of ST3PS steel surface layers. Voltage pulses with an in...In the work, we studied the effect of the plasma of a runaway electron preionized （REP） diffuse discharge （DD） on the composition, structure, and properties of ST3PS steel surface layers. Voltage pulses with an incident wave amplitude of up to 30 kV, FWHM of around 4 ns, and rise time of around 2.5 ns were applied to the gap in an inhomogeneous electric field. The ST3PS steel specimens exposed to this type of discharge revealed changes in their defect subsystem, suggesting that the runaway electron preionized diffuse discharge provides surface hardening of the steel.展开更多
Ferroelectric polymers are the mainstay of advanced flexible electronic devices.How to tailor the ferroelectric polymer films for various applications via simple processing approaches is challenging.Here we demonstrat...Ferroelectric polymers are the mainstay of advanced flexible electronic devices.How to tailor the ferroelectric polymer films for various applications via simple processing approaches is challenging.Here we demonstrate the tuning of ferroelectric responses can be achieved in polymer blends of poly(vinylidene fluoride-trifluoroethylene)(P(VDF-TrFE))and polymethyl methacrylate(PMMA)prepared via a simple two-step process.The proposed two-step process endows the polymer blends with a random distribution of P(VDF-TrFE)crystalline phase,hence decoupling the coherent ferroelectric domain interactions between continuous ordered crystalline phases that ubiquitously existed in common P(VDF-TrFE)film.The incorporation of the miscible non-crystalline PMMA chains with low-polarity results in reversal dipoles and a transition from ferroelectric to antiferroelectric-like behavior,overcoming the trade-off between the polarization and depolarization fields.In particular,resultant excellent mechanical and electrical properties of the polymer blend films give rise to remarkably improved breakdown strength and energy storage performance,surpassing P(VDF-TrFE)and commercial biaxial-oriented polypropylene films.This work provides a simple and effective strategy to tailor the ferroelectric response of polymeric materials with great potential for flexible electrical energy storage applications.展开更多
To simulate the nonlinear behavior of ferroelectric structures and devices under non-uniform electromechanical loadings,a domain-switching embedded electromechanical finite element method is developed in this paper.Fo...To simulate the nonlinear behavior of ferroelectric structures and devices under non-uniform electromechanical loadings,a domain-switching embedded electromechanical finite element method is developed in this paper.Following continuum assumption,the electromechanical behavior of each representative material point can be obtained by averaging the behavior of the local corresponding microstructure,e.g.42 domains used in this work.A new Double Gibbs free energy criterion for domain-switching is proposed to ensure the convergence and stability of the simulations on ferroelectrics under non-uniform field.Several computational examples are given to demonstrate that this nonlinear finite element method can yield reasonable and stable simulation results which can be used to explain some experimental results and assist the design of ferroelectric devices.展开更多
Multiferroic materials exhibit tremendous potentials in novel magnetoelectric devices such as high-density non-volatile storage.Herein,we report the coexistence of ferroelectricity and ferromagnetism in two-dimensiona...Multiferroic materials exhibit tremendous potentials in novel magnetoelectric devices such as high-density non-volatile storage.Herein,we report the coexistence of ferroelectricity and ferromagnetism in two-dimensional Fedoped In2Se3(Fe0.16In1.84Se3,FIS).The Fe atoms were doped at the In atom sites and the Fe content is^3.22%according to the experiments.Our first-principles calculation based on the density-functional theory predicts a magnetic moment of 5μB per Fe atom when Fe substitutes In sites in In2Se3.The theoretical prediction was further confirmed experimentally by magnetic measurement.The results indicate that pure In2Se3 is diamagnetic,whereas FIS exhibits ferromagnetic behavior with a parallel anisotropy at 2 K and a Curie temperature of^8 K.Furthermore,the sample maintains stable room-temperature ferroelectricity in piezoresponse force microscopy(PFM)measurement after the introduction of Fe atom into the ferroelectric In2Se3 nanoflakes.The findings indicate that the layered Fe0.16In1.84Se3 materials have potential in future nanoelectronic,magnetic,and optoelectronic applications.展开更多
文摘In the work, we studied the effect of the plasma of a runaway electron preionized （REP） diffuse discharge （DD） on the composition, structure, and properties of ST3PS steel surface layers. Voltage pulses with an incident wave amplitude of up to 30 kV, FWHM of around 4 ns, and rise time of around 2.5 ns were applied to the gap in an inhomogeneous electric field. The ST3PS steel specimens exposed to this type of discharge revealed changes in their defect subsystem, suggesting that the runaway electron preionized diffuse discharge provides surface hardening of the steel.
基金supported by the Basic Science Center Program of the National Natural Science Foundation of China(51788104)the National Natural Science Foundation of China(51802237,52072280,51872214 and 51872079)+2 种基金the Young Elite Scientists Sponsorship Program by CAST(2018QNRC001)the Open Fund of Hubei Key Laboratory of Ferro&Piezoelectric Materials and Devices(K201807)the Fundamental Research Funds for the Central Universities(193201002,183101005 and 182401004)。
文摘Ferroelectric polymers are the mainstay of advanced flexible electronic devices.How to tailor the ferroelectric polymer films for various applications via simple processing approaches is challenging.Here we demonstrate the tuning of ferroelectric responses can be achieved in polymer blends of poly(vinylidene fluoride-trifluoroethylene)(P(VDF-TrFE))and polymethyl methacrylate(PMMA)prepared via a simple two-step process.The proposed two-step process endows the polymer blends with a random distribution of P(VDF-TrFE)crystalline phase,hence decoupling the coherent ferroelectric domain interactions between continuous ordered crystalline phases that ubiquitously existed in common P(VDF-TrFE)film.The incorporation of the miscible non-crystalline PMMA chains with low-polarity results in reversal dipoles and a transition from ferroelectric to antiferroelectric-like behavior,overcoming the trade-off between the polarization and depolarization fields.In particular,resultant excellent mechanical and electrical properties of the polymer blend films give rise to remarkably improved breakdown strength and energy storage performance,surpassing P(VDF-TrFE)and commercial biaxial-oriented polypropylene films.This work provides a simple and effective strategy to tailor the ferroelectric response of polymeric materials with great potential for flexible electrical energy storage applications.
基金supported by the National Natural Science Foundation of China(Grant Nos. 10702034,10732050,90816006 and 10820101048)the National Basic Research Program of China(Grant Nos.2007CB936803 and 2010CB832701)
文摘To simulate the nonlinear behavior of ferroelectric structures and devices under non-uniform electromechanical loadings,a domain-switching embedded electromechanical finite element method is developed in this paper.Following continuum assumption,the electromechanical behavior of each representative material point can be obtained by averaging the behavior of the local corresponding microstructure,e.g.42 domains used in this work.A new Double Gibbs free energy criterion for domain-switching is proposed to ensure the convergence and stability of the simulations on ferroelectrics under non-uniform field.Several computational examples are given to demonstrate that this nonlinear finite element method can yield reasonable and stable simulation results which can be used to explain some experimental results and assist the design of ferroelectric devices.
基金financially supported by the National Key Research and Development Program of China (2017YFA0207500)the National Natural Science Foundation of China (61622406, 61571415 and 51502283)+1 种基金the Strategic Priority Research Program of Chinese Academy of Sciences (XDB30000000)Beijing Academy of Quantum Information Sciences (Y18G04)
文摘Multiferroic materials exhibit tremendous potentials in novel magnetoelectric devices such as high-density non-volatile storage.Herein,we report the coexistence of ferroelectricity and ferromagnetism in two-dimensional Fedoped In2Se3(Fe0.16In1.84Se3,FIS).The Fe atoms were doped at the In atom sites and the Fe content is^3.22%according to the experiments.Our first-principles calculation based on the density-functional theory predicts a magnetic moment of 5μB per Fe atom when Fe substitutes In sites in In2Se3.The theoretical prediction was further confirmed experimentally by magnetic measurement.The results indicate that pure In2Se3 is diamagnetic,whereas FIS exhibits ferromagnetic behavior with a parallel anisotropy at 2 K and a Curie temperature of^8 K.Furthermore,the sample maintains stable room-temperature ferroelectricity in piezoresponse force microscopy(PFM)measurement after the introduction of Fe atom into the ferroelectric In2Se3 nanoflakes.The findings indicate that the layered Fe0.16In1.84Se3 materials have potential in future nanoelectronic,magnetic,and optoelectronic applications.
