A structure-dependent explicit method with enhanced stability properties is proposed in this study. In general, the method offers unconditional stability for structural systems except those with a particular instantan...A structure-dependent explicit method with enhanced stability properties is proposed in this study. In general, the method offers unconditional stability for structural systems except those with a particular instantaneous stiffness hardening behavior. In addition, it is second-order accurate and displays no overshooting in high frequency responses. Numerical experiments reveal that the proposed method saves a substantial amount of computational effort in solving inertial problems where only the low frequency responses are of interest, when compared to a general second-order accurate integration method.展开更多
The feasibility of using a problem-dependent method to solve systems of second order ODEs is corroborated by an eigen-based theory and a methodology to develop such a numerical method is constructed.The key steps of t...The feasibility of using a problem-dependent method to solve systems of second order ODEs is corroborated by an eigen-based theory and a methodology to develop such a numerical method is constructed.The key steps of this methodology are to decouple a system of ODEs of second order into a set of uncoupled ODEs of second order;next,an eigen-dependent method is proposed to approximate the solution of each uncoupled ODE of second order.It is vital to transform all eigen-dependent methods to a problem-dependent method to bypass an Eigen analysis.The development of an eigen-dependent method plays a key role in this methodology so that slow eigenmodes can be accurately integrated while there is no instability or excessive amplitude growth in fast eigenmodes.This can explain why a problem-dependent method can simultaneously combine the explicitness of each step and A-stability.Consequently,huge computational efforts can be saved for solving nonlinear stiff problems.A new family of problem-dependent methods is developed in this work so that the feasibility of the proposed methodology can be affirmed.It has almost the same performance as that of the HHT-αmethod.However,it can save more than 99.5%of CPU demand in approximating a solution for a system of 1000 nonlinear second order ODEs.展开更多
Organic vip-host doped systems possessing roomtemperature phosphorescence(RTP)have attracted substantial attention.Conventionally,researchers have primarily focused on the correlation between the electronic properti...Organic vip-host doped systems possessing roomtemperature phosphorescence(RTP)have attracted substantial attention.Conventionally,researchers have primarily focused on the correlation between the electronic properties and energy levels of molecules and their corresponding RTP behavior.While the role of the adaptability of molecular structure in modulating RTP is overlooked,it calls for further exploration.Herein,a series of vip-host systems were designed to realize bright red RTP with precisely structural regulation.Three naphthalimide derivatives with alkyl linkers of different lengths were utilized as vips and doped in hosts of three corresponding phthalimide derivatives.The doped systems with matched structures containing the exact-length alkyl linker exhibited a remarkable enhancement over 100 fold in RTP,analogous to the correct key fitting the right lock.In contrast,doped systems with mismatched structures showed almost undetectable RTP.Experimental results demonstrate that the suppression of nonradiative transition and structuredependent energy transfer of triplet excitons in the doped system play a crucial role in precisely structural matching,given that all vips possess similar electronic configurations and energy levels of excited states.This research may offer a novel insight into understanding the relationship between themolecular morphology and the RTP performance in host-vip systems.展开更多
基金The Science Council,Chinese Taipei Under Grant No.NSC-99-2221-E-027-029
文摘A structure-dependent explicit method with enhanced stability properties is proposed in this study. In general, the method offers unconditional stability for structural systems except those with a particular instantaneous stiffness hardening behavior. In addition, it is second-order accurate and displays no overshooting in high frequency responses. Numerical experiments reveal that the proposed method saves a substantial amount of computational effort in solving inertial problems where only the low frequency responses are of interest, when compared to a general second-order accurate integration method.
文摘The feasibility of using a problem-dependent method to solve systems of second order ODEs is corroborated by an eigen-based theory and a methodology to develop such a numerical method is constructed.The key steps of this methodology are to decouple a system of ODEs of second order into a set of uncoupled ODEs of second order;next,an eigen-dependent method is proposed to approximate the solution of each uncoupled ODE of second order.It is vital to transform all eigen-dependent methods to a problem-dependent method to bypass an Eigen analysis.The development of an eigen-dependent method plays a key role in this methodology so that slow eigenmodes can be accurately integrated while there is no instability or excessive amplitude growth in fast eigenmodes.This can explain why a problem-dependent method can simultaneously combine the explicitness of each step and A-stability.Consequently,huge computational efforts can be saved for solving nonlinear stiff problems.A new family of problem-dependent methods is developed in this work so that the feasibility of the proposed methodology can be affirmed.It has almost the same performance as that of the HHT-αmethod.However,it can save more than 99.5%of CPU demand in approximating a solution for a system of 1000 nonlinear second order ODEs.
基金the financial support from the National Natural Science Foundation of China(grant nos.52373199,52073315,and 52473195)Scientific Research Platforms and Projects of University of Department of Education of Guangdong Province(grant no.2024KCXTD009)+1 种基金Key Discipline Research Capability Enhancement Project of Department of Education of Guangdong Province(grant no.2024ZDJS037)Fundamental Research Funds for the Central Universities,Sun Yat-sen University(grant no.23yxqntd002)。
文摘Organic vip-host doped systems possessing roomtemperature phosphorescence(RTP)have attracted substantial attention.Conventionally,researchers have primarily focused on the correlation between the electronic properties and energy levels of molecules and their corresponding RTP behavior.While the role of the adaptability of molecular structure in modulating RTP is overlooked,it calls for further exploration.Herein,a series of vip-host systems were designed to realize bright red RTP with precisely structural regulation.Three naphthalimide derivatives with alkyl linkers of different lengths were utilized as vips and doped in hosts of three corresponding phthalimide derivatives.The doped systems with matched structures containing the exact-length alkyl linker exhibited a remarkable enhancement over 100 fold in RTP,analogous to the correct key fitting the right lock.In contrast,doped systems with mismatched structures showed almost undetectable RTP.Experimental results demonstrate that the suppression of nonradiative transition and structuredependent energy transfer of triplet excitons in the doped system play a crucial role in precisely structural matching,given that all vips possess similar electronic configurations and energy levels of excited states.This research may offer a novel insight into understanding the relationship between themolecular morphology and the RTP performance in host-vip systems.
