Semiconductor-based electronic devices usually work under multiphysics fields rendering complex electromagnetic-thermo-mechanical coupling.In this work,we develop a penalty function method based on a finite element an...Semiconductor-based electronic devices usually work under multiphysics fields rendering complex electromagnetic-thermo-mechanical coupling.In this work,we develop a penalty function method based on a finite element analysis to tackle this coupling behavior in a metal/semiconductor bilayer plate-the representative unit of semiconductor antenna,which receives strong and pulsed electromagnetic signals.Under these pulses,eddy current is generated,of which the magnitude varies remarkably from one plate to another due to the difference in electrical conductivity.In the concerned system,the metal layer generates much larger current,resulting in the large temperature rise and the nonnegligible Lorentz force,which could lead to delamination and failure of the semiconductor-based electronic device.This study provides theoretical guidance for the design and protection of semiconductor-based electronic devices in complex environments.展开更多
The thermal properties of a nanostructured semiconductor are affected by multi-physical fields,such as stress and electromagnetic fields,causing changes in temperature and strain distributions.In this work,the influen...The thermal properties of a nanostructured semiconductor are affected by multi-physical fields,such as stress and electromagnetic fields,causing changes in temperature and strain distributions.In this work,the influence of stress-dependent thermal conductivity on the heat transfer behavior of a GaN-based nanofilm is investigated.The finite element method is adopted to simulate the temperature distribution in a prestressed nanofilm under heat pulses.Numerical results demonstrate the effect of stress field on the thermal conductivity of GaN-based nanofilm,namely,the prestress and the thermal stress lead to a change in the heat transfer behavior in the nanofilm.Under the same heat source,the peak temperature of the film with stress-dependent thermal conductivity is significantly lower than that of the film with a constant thermal conductivity and the maximum temperature difference can reach 8.2 K.These results could be useful for designing GaN-based semiconductor devices with higher reliability under multi-physical fields.展开更多
The observations of microorganisms revealed how they swim.As inspired by them,studies on artificial micro-robots with various actuation mechanisms have been thriving.To elucidate the essential concepts in understandin...The observations of microorganisms revealed how they swim.As inspired by them,studies on artificial micro-robots with various actuation mechanisms have been thriving.To elucidate the essential concepts in understanding the dynamic behaviors of natural and artificial micro-swimmers—so as to control the latter in future applications,in this paper,we summarize the historical achievements and describe our theoretical perspectives.We first introduce the studies on microorganisms and their propulsion mechanisms.After reviewing the basic principles and the development of the understanding of them,we take the flagellated micro-swimmers as an example to elaborate on the theories of their locomotion.We review the progress in actuation strategies of artificial flagellated micro-swimmers and then propose two possible strategies to realize the turning of a flagellated micro-swimmer—the key step toward steerability through remote fields.Finally,we describe the inadequacies of the investigations on this topic and our perspectives on future developments.展开更多
基金the National Natural Science Foundation of China(Grant nos.11772294,11621062)the Fundamental Research Funds for the Central Universities(Grant no.2017QNA4031).
文摘Semiconductor-based electronic devices usually work under multiphysics fields rendering complex electromagnetic-thermo-mechanical coupling.In this work,we develop a penalty function method based on a finite element analysis to tackle this coupling behavior in a metal/semiconductor bilayer plate-the representative unit of semiconductor antenna,which receives strong and pulsed electromagnetic signals.Under these pulses,eddy current is generated,of which the magnitude varies remarkably from one plate to another due to the difference in electrical conductivity.In the concerned system,the metal layer generates much larger current,resulting in the large temperature rise and the nonnegligible Lorentz force,which could lead to delamination and failure of the semiconductor-based electronic device.This study provides theoretical guidance for the design and protection of semiconductor-based electronic devices in complex environments.
基金This research is supported by the National Natural Science Foundation of China(Grant Nos.11772294,11621062)the Fundamental Research Funds for the Central Universities(Grant No.2017QNA4031).
文摘The thermal properties of a nanostructured semiconductor are affected by multi-physical fields,such as stress and electromagnetic fields,causing changes in temperature and strain distributions.In this work,the influence of stress-dependent thermal conductivity on the heat transfer behavior of a GaN-based nanofilm is investigated.The finite element method is adopted to simulate the temperature distribution in a prestressed nanofilm under heat pulses.Numerical results demonstrate the effect of stress field on the thermal conductivity of GaN-based nanofilm,namely,the prestress and the thermal stress lead to a change in the heat transfer behavior in the nanofilm.Under the same heat source,the peak temperature of the film with stress-dependent thermal conductivity is significantly lower than that of the film with a constant thermal conductivity and the maximum temperature difference can reach 8.2 K.These results could be useful for designing GaN-based semiconductor devices with higher reliability under multi-physical fields.
基金the General Research Fund of Hong Kong RGC(Grant No.15213619)The second author is supported by the postdoctoral scheme of the Hong Kong Polytechnic University(Project ID:P0034926)+1 种基金The studies presented in this work are supported by the NSFC/RGC Joint Research Scheme(RGC:N_PolyU519/19 and NSFC:51961160729)The authors are grateful for these financial supports.
文摘The observations of microorganisms revealed how they swim.As inspired by them,studies on artificial micro-robots with various actuation mechanisms have been thriving.To elucidate the essential concepts in understanding the dynamic behaviors of natural and artificial micro-swimmers—so as to control the latter in future applications,in this paper,we summarize the historical achievements and describe our theoretical perspectives.We first introduce the studies on microorganisms and their propulsion mechanisms.After reviewing the basic principles and the development of the understanding of them,we take the flagellated micro-swimmers as an example to elaborate on the theories of their locomotion.We review the progress in actuation strategies of artificial flagellated micro-swimmers and then propose two possible strategies to realize the turning of a flagellated micro-swimmer—the key step toward steerability through remote fields.Finally,we describe the inadequacies of the investigations on this topic and our perspectives on future developments.
