The transient backscattering mechanisms of a dipole array with reflector have been investigated from different aspects： time-domain, frequency-domain, and combined time-frequency domain, using 4 × 8 dipole array...The transient backscattering mechanisms of a dipole array with reflector have been investigated from different aspects： time-domain, frequency-domain, and combined time-frequency domain, using 4 × 8 dipole arrays with reflector as an example. The data of scattering from the arrays under the incidence of Gaussian pulses are obtained by finite differential time domain method. The influences of the array structural parameters, incident wave parameters, and incident angles on the waveforms, spectrum, and time-frequency representations of the backscattered fields of the arrays are analysed and conclusions are drawn. From these characteristics and conclusions, it is possible to deduce the array structure inversely from the backscattered field.展开更多
Dynamic functional materials have attracted increasing interest owing to their broad potential applications in the field of flexible smart.Molecular rotors are a good platform to achieve functionality because of the i...Dynamic functional materials have attracted increasing interest owing to their broad potential applications in the field of flexible smart.Molecular rotors are a good platform to achieve functionality because of the intrinsic movement of the internal components.Herein,we report a two-dimensional(2D)Ruddlesden–Popper(RP)type hybrid perovskite ferroelastic(TFCA)2CdCl4(1;TFCA=2-fluoro-1-amino-pyrrolidium)showing T_(c)(402 K)and spontaneous strain(0.071).Impressively,the rapid rotating motions of the polar rotors lead to the fast reorientation of the dipoles resulting in a large dielectric response.The switching on–off ratio of dielectric anomaly is more than 100(ε’HTP/ε’LTP>100)at a high-frequency electric field(1 MHz).This study reveals that the 2D RP hybrid perovskite molecular rotor platform provides a new avenue to explore dynamic functional materials.展开更多
This paper constructs a concentric ellipsoid torso-heart model by boundary element method and investigates the impacts of model structures on the cardiac magnetic fields generated by both equivalent primary source--a ...This paper constructs a concentric ellipsoid torso-heart model by boundary element method and investigates the impacts of model structures on the cardiac magnetic fields generated by both equivalent primary source--a current dipole and volume currents. Then by using the simulated magnetic fields based on torso-heart model as input, the cardiac current sources--an array of current dipoles by optimal constrained linear inverse method are constructed. Next, the current dipole array reconstruction considering boundaries is compared with that in an unbounded homogeneous medium. Furthermore, the influence of random noise on reconstruction is also considered and the reconstructing effect is judged by several reconstructing parameters.展开更多
An equivalent radiation source method is proposed to characterize electromagnetic emission and interference of complex three dimensional integrated circuits（IC） in this paper.The method utilizes amplitude-only near-...An equivalent radiation source method is proposed to characterize electromagnetic emission and interference of complex three dimensional integrated circuits（IC） in this paper.The method utilizes amplitude-only near-field scanning data to reconstruct an equivalent magnetic dipole array,and the differential evolution optimization algorithm is proposed to extract the locations,orientation and moments of those dipoles.By importing the equivalent dipoles model into a 3D full-wave simulator together with the victim circuit model,the electromagnetic interference issues in mixed RF/digital systems can be well predicted.A commercial IC is used to validate the accuracy and efficiency of this proposed method.The coupled power at the victim antenna port calculated by the equivalent radiation source is compared with the measured data.Good consistency is obtained which confirms the validity and efficiency of the method.展开更多
基金Project supported by the Foundations of Beijing Jiaotong Universitythe Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry
文摘The transient backscattering mechanisms of a dipole array with reflector have been investigated from different aspects： time-domain, frequency-domain, and combined time-frequency domain, using 4 × 8 dipole arrays with reflector as an example. The data of scattering from the arrays under the incidence of Gaussian pulses are obtained by finite differential time domain method. The influences of the array structural parameters, incident wave parameters, and incident angles on the waveforms, spectrum, and time-frequency representations of the backscattered fields of the arrays are analysed and conclusions are drawn. From these characteristics and conclusions, it is possible to deduce the array structure inversely from the backscattered field.
基金support from the National Natural Science Foundation of China(Grant No.22175079)support from National Natural Science Foundation of China(Grant No.22205087)+3 种基金Open Project Program of Jiangxi Provincial Key Laboratory of Functional Molecular Materials Chemistry,Jiangxi University of Science and Technology,(Grant No.20212BCD42018)Science and Technology Project of Jiangxi Provincial Department of Education(GJJ210812)support from National Natural Science Foundation of China(Grant No.21875093 and 22275075)Natural Science Foundation of Jiangxi Province(Grant No.20204BCJ22015 and 20202ACBL203001).
文摘Dynamic functional materials have attracted increasing interest owing to their broad potential applications in the field of flexible smart.Molecular rotors are a good platform to achieve functionality because of the intrinsic movement of the internal components.Herein,we report a two-dimensional(2D)Ruddlesden–Popper(RP)type hybrid perovskite ferroelastic(TFCA)2CdCl4(1;TFCA=2-fluoro-1-amino-pyrrolidium)showing T_(c)(402 K)and spontaneous strain(0.071).Impressively,the rapid rotating motions of the polar rotors lead to the fast reorientation of the dipoles resulting in a large dielectric response.The switching on–off ratio of dielectric anomaly is more than 100(ε’HTP/ε’LTP>100)at a high-frequency electric field(1 MHz).This study reveals that the 2D RP hybrid perovskite molecular rotor platform provides a new avenue to explore dynamic functional materials.
基金Project supported by the State Key Development Program for Basic Research of China(Grant No.2006CB601007)the National Natural Science Foundation of China(Grant No.10674006)the National High Technology Research and Development Program of China(Grant No.2007AA03Z238)
文摘This paper constructs a concentric ellipsoid torso-heart model by boundary element method and investigates the impacts of model structures on the cardiac magnetic fields generated by both equivalent primary source--a current dipole and volume currents. Then by using the simulated magnetic fields based on torso-heart model as input, the cardiac current sources--an array of current dipoles by optimal constrained linear inverse method are constructed. Next, the current dipole array reconstruction considering boundaries is compared with that in an unbounded homogeneous medium. Furthermore, the influence of random noise on reconstruction is also considered and the reconstructing effect is judged by several reconstructing parameters.
基金supported by the National Nature Science Foundation of China(No.61274110)
文摘An equivalent radiation source method is proposed to characterize electromagnetic emission and interference of complex three dimensional integrated circuits（IC） in this paper.The method utilizes amplitude-only near-field scanning data to reconstruct an equivalent magnetic dipole array,and the differential evolution optimization algorithm is proposed to extract the locations,orientation and moments of those dipoles.By importing the equivalent dipoles model into a 3D full-wave simulator together with the victim circuit model,the electromagnetic interference issues in mixed RF/digital systems can be well predicted.A commercial IC is used to validate the accuracy and efficiency of this proposed method.The coupled power at the victim antenna port calculated by the equivalent radiation source is compared with the measured data.Good consistency is obtained which confirms the validity and efficiency of the method.
