This study systematically investigates the mechanical response characteristics of Mo-10Cu pseudo-alloy under various conditions,including temperatures ranging from 298 K to 550 K,strain rates from1×10^(-2)s^(-1)t...This study systematically investigates the mechanical response characteristics of Mo-10Cu pseudo-alloy under various conditions,including temperatures ranging from 298 K to 550 K,strain rates from1×10^(-2)s^(-1)to 5.2×10^(3)s^(-1),and dynamic impact loads from 134 m/s to 837 m/s.The investigation is conducted using a combination of multi-method crossover experiment and numerical simulations,with accuracy validated through X-ray testing and static penetration test.Using a universal testing machine,Split-Hopkinson Pressure Bar(SHPB)system,and a light-gas gun,the dynamic constitutive behavior and shock adiabatic curves of the alloy under complex loading conditions are revealed.Experimental results demonstrate that the flow stress evolution of Mo-10Cu alloy exhibits significant strain hardening,and strain-rate strengthening.Based on these observations,a Johnson-Cook(J-C)constitutive model has been developed to describe the material's dynamic behavior.Through free-surface particle velocity measurements,the shock adiabatic relationship was obtained,and a Gruneisen equation of state was established.X-ray experimental results confirm that the Mo-10Cu liner can generate well-formed,cohesive jets.The penetration test results show that the maximum penetration depth can reach243.10 mm.The maximum error between the numerical simulation and the X-ray test is less than 7.70%,and the error with the penetration test is 4.73%,which confirms the accuracy of the constitutive parameters and the state equation.In conclusion,the proposed J-C model and Gruneisen equation effectively predict the dynamic response and jet formation characteristics of Mo-10Cu alloy under extreme loads.This work provides both theoretical support and experimental data for material design and performance optimization in shaped charge applications.展开更多
在孤岛直流微电网系统中,线路阻抗不匹配会影响各线路的电流分配精度和荷电状态(state of charge,SOC)均衡效果。同时,由于采用下垂控制,虚拟阻抗的存在也会导致直流母线电压下降。针对以上问题,提出了一种基于自适应虚拟阻抗的SOC均衡...在孤岛直流微电网系统中,线路阻抗不匹配会影响各线路的电流分配精度和荷电状态(state of charge,SOC)均衡效果。同时,由于采用下垂控制,虚拟阻抗的存在也会导致直流母线电压下降。针对以上问题,提出了一种基于自适应虚拟阻抗的SOC均衡控制策略。该策略考虑了不同容量的分布式储能单元(distributed energy storage units,DESUs),并设计了交互DESUs邻居单元SOC均衡差异信息的收敛因子,以加快SOC均衡速度。利用结合多种系统状态信息的状态因子,通过单补偿环节即可实现输出电流的精准分配以及母线电压的恢复。使用改进后的动态平均一致性算法获取系统全局平均状态信息估计值。最后,在Matlab/Simulink仿真软件中搭建了4种工况模型,验证了所提控制策略的有效性和可靠性。展开更多
针对目前荷电状态(state of charge,SOC)估计方法考虑温度与退化共同影响及其关联耦合关系较少,导致电池性能退化后的模型表征不完善、SOC估计精度不足的问题,提出一种基于退化注入场路耦合模型的锂电池SOC估计方法,以实现全寿命周期下...针对目前荷电状态(state of charge,SOC)估计方法考虑温度与退化共同影响及其关联耦合关系较少,导致电池性能退化后的模型表征不完善、SOC估计精度不足的问题,提出一种基于退化注入场路耦合模型的锂电池SOC估计方法,以实现全寿命周期下SOC的准确估计。首先建立等效电路模型与多物理场模型耦合的场路耦合模型,刻画温度的影响;进而使用离线参数辨识方法将温度、退化等因素注入等效电路模型参数中;最终建立代理模型提高计算效率,实现在线SOC估计。案例验证结果表明,在锂电池经过长时间运行发生退化后,相比于其他方法,所提方法的估计结果具有更平稳的曲线和更高的精度。展开更多
针对微电网多储能单元因荷电状态、额定容量和线路阻抗差异导致部分储能单元过充过放,影响其使用寿命进而使微网稳定性调节能力变差的问题,提出一种基于变调节因子的多储能荷电状态(state of charge,SoC)均衡策略,通过反余切函数将下垂...针对微电网多储能单元因荷电状态、额定容量和线路阻抗差异导致部分储能单元过充过放,影响其使用寿命进而使微网稳定性调节能力变差的问题,提出一种基于变调节因子的多储能荷电状态(state of charge,SoC)均衡策略,通过反余切函数将下垂系数与SoC、额定容量关联,并引入虚拟压降补偿环节,实现多组储能单元间SoC均衡。在此基础上设计变调节因子,提高SoC均衡速度。仿真结果验证了所提策略能实现多组储能单元间SoC均衡,有效提升SoC均衡速度,并消除线路阻抗对SoC均衡及电流分配精度的影响。展开更多
为解决高渗透率区域电网存在转动惯量降低、系统调频能力下降、频率稳定性降低等问题,在储能调频的基础上,增加风电机组调频控制,通过分析风电渗透率δ对系统的影响,从减小电池损耗、延长储能寿命的角度出发,提出1种考虑荷电状态SOC(sta...为解决高渗透率区域电网存在转动惯量降低、系统调频能力下降、频率稳定性降低等问题,在储能调频的基础上,增加风电机组调频控制,通过分析风电渗透率δ对系统的影响,从减小电池损耗、延长储能寿命的角度出发,提出1种考虑荷电状态SOC(state-of-charge)和δ影响的自适应风储协同一次调频控制PFRC(primary frequency regulation control)策略。该控制策略由考虑SOC和调频死区的储能自适应PFRC和考虑δ的风电自适应PFRC策略协同配合,能够有效提高系统稳定性和电网调频效果。在阶跃扰动下频率的跌落最低点由0.33变为0.07,连续负荷扰动下所提控制策略与单一储能调频相比,频率质量由3.966变为1.676,SOC质量由0.06407变为0.01648,储能SOC变化更加平缓,能够节省储能容量的配置,减小储能单元的损耗,相对于单一储能调频能够达到更好的调频效果,维持系统稳定运行。最后通过在MATLAB/Simulink中搭建区域电网模型,验证控制策略的有效性。展开更多
A global and local charge transfer partitioning model,based on the cornerstone theory developed by Robert G.Parr and Robert G.Pearson,which introduces two charge transfer channels(one for accepting electrons(electroph...A global and local charge transfer partitioning model,based on the cornerstone theory developed by Robert G.Parr and Robert G.Pearson,which introduces two charge transfer channels(one for accepting electrons(electrophilic) and another for donating(nucleophilic)),is applied to the reaction of a set of indoles with 4,6-dinitrobenzofuroxan.The global analysis indicates that the prevalent electron transfer mechanism in the reaction is a nucleophilic one on the indoles,i.e.,the indoles under consideration transfer electrons to 4,6-dinitrobenzofuroxan.Evaluating the reactivity descriptorswith exchange-correlation functionals including exact exchange(global hybrids) yields slightly better correlations than those obtained with generalized gradient-approximated functionals;however,the trends are preserved.Comparing the trend obtained with the number of electrons donated by the indoles,and predicted by the partitioning model,with that observed experimentally based on the measured rate constants,we propose that the number of electrons transferred through this channel can be used as a nucleophilicity scale to order the reactivity of indoles towards 4,6-dinitrobenzofuroxan.This approach to obtain reactivity scales has the advantage of depending on the intrinsic properties of the two reacting species;therefore,it opens the possibility that the same group of molecules may show different reactivity trends depending on the species with which they are reacting.The local model allows systematic incorporation of the reactive atoms based on the their decreasing condensed Fukui functions,and the correlations obtained by increasing the number of reactive atoms participating in the local analysis of the transferred nucleophilic charge improve,reaching an optimal correlation,which in the present case indicates keeping three atoms from the indoles and two from 4,6-dinitrobenzofuroxan.The atoms selected by this procedure provide valuable information about the local reactivity of the indoles.We further show that this information about the most reactive atoms on each reactant,combined with the spatial distribution of the nucleophilic and electrophilic Fukui functions of both reactants,allows one to propose non-trivial candidates of starting geometries for the search of the transition state structures present in these reactions.展开更多
基金funded by the China Postdoctoral Science Foundation(Grant No.2022M721614)。
文摘This study systematically investigates the mechanical response characteristics of Mo-10Cu pseudo-alloy under various conditions,including temperatures ranging from 298 K to 550 K,strain rates from1×10^(-2)s^(-1)to 5.2×10^(3)s^(-1),and dynamic impact loads from 134 m/s to 837 m/s.The investigation is conducted using a combination of multi-method crossover experiment and numerical simulations,with accuracy validated through X-ray testing and static penetration test.Using a universal testing machine,Split-Hopkinson Pressure Bar(SHPB)system,and a light-gas gun,the dynamic constitutive behavior and shock adiabatic curves of the alloy under complex loading conditions are revealed.Experimental results demonstrate that the flow stress evolution of Mo-10Cu alloy exhibits significant strain hardening,and strain-rate strengthening.Based on these observations,a Johnson-Cook(J-C)constitutive model has been developed to describe the material's dynamic behavior.Through free-surface particle velocity measurements,the shock adiabatic relationship was obtained,and a Gruneisen equation of state was established.X-ray experimental results confirm that the Mo-10Cu liner can generate well-formed,cohesive jets.The penetration test results show that the maximum penetration depth can reach243.10 mm.The maximum error between the numerical simulation and the X-ray test is less than 7.70%,and the error with the penetration test is 4.73%,which confirms the accuracy of the constitutive parameters and the state equation.In conclusion,the proposed J-C model and Gruneisen equation effectively predict the dynamic response and jet formation characteristics of Mo-10Cu alloy under extreme loads.This work provides both theoretical support and experimental data for material design and performance optimization in shaped charge applications.
文摘在孤岛直流微电网系统中,线路阻抗不匹配会影响各线路的电流分配精度和荷电状态(state of charge,SOC)均衡效果。同时,由于采用下垂控制,虚拟阻抗的存在也会导致直流母线电压下降。针对以上问题,提出了一种基于自适应虚拟阻抗的SOC均衡控制策略。该策略考虑了不同容量的分布式储能单元(distributed energy storage units,DESUs),并设计了交互DESUs邻居单元SOC均衡差异信息的收敛因子,以加快SOC均衡速度。利用结合多种系统状态信息的状态因子,通过单补偿环节即可实现输出电流的精准分配以及母线电压的恢复。使用改进后的动态平均一致性算法获取系统全局平均状态信息估计值。最后,在Matlab/Simulink仿真软件中搭建了4种工况模型,验证了所提控制策略的有效性和可靠性。
文摘针对目前荷电状态(state of charge,SOC)估计方法考虑温度与退化共同影响及其关联耦合关系较少,导致电池性能退化后的模型表征不完善、SOC估计精度不足的问题,提出一种基于退化注入场路耦合模型的锂电池SOC估计方法,以实现全寿命周期下SOC的准确估计。首先建立等效电路模型与多物理场模型耦合的场路耦合模型,刻画温度的影响;进而使用离线参数辨识方法将温度、退化等因素注入等效电路模型参数中;最终建立代理模型提高计算效率,实现在线SOC估计。案例验证结果表明,在锂电池经过长时间运行发生退化后,相比于其他方法,所提方法的估计结果具有更平稳的曲线和更高的精度。
文摘针对微电网多储能单元因荷电状态、额定容量和线路阻抗差异导致部分储能单元过充过放,影响其使用寿命进而使微网稳定性调节能力变差的问题,提出一种基于变调节因子的多储能荷电状态(state of charge,SoC)均衡策略,通过反余切函数将下垂系数与SoC、额定容量关联,并引入虚拟压降补偿环节,实现多组储能单元间SoC均衡。在此基础上设计变调节因子,提高SoC均衡速度。仿真结果验证了所提策略能实现多组储能单元间SoC均衡,有效提升SoC均衡速度,并消除线路阻抗对SoC均衡及电流分配精度的影响。
文摘为解决高渗透率区域电网存在转动惯量降低、系统调频能力下降、频率稳定性降低等问题,在储能调频的基础上,增加风电机组调频控制,通过分析风电渗透率δ对系统的影响,从减小电池损耗、延长储能寿命的角度出发,提出1种考虑荷电状态SOC(state-of-charge)和δ影响的自适应风储协同一次调频控制PFRC(primary frequency regulation control)策略。该控制策略由考虑SOC和调频死区的储能自适应PFRC和考虑δ的风电自适应PFRC策略协同配合,能够有效提高系统稳定性和电网调频效果。在阶跃扰动下频率的跌落最低点由0.33变为0.07,连续负荷扰动下所提控制策略与单一储能调频相比,频率质量由3.966变为1.676,SOC质量由0.06407变为0.01648,储能SOC变化更加平缓,能够节省储能容量的配置,减小储能单元的损耗,相对于单一储能调频能够达到更好的调频效果,维持系统稳定运行。最后通过在MATLAB/Simulink中搭建区域电网模型,验证控制策略的有效性。
基金UOV was supported in part by Conacyt through a doctoral fellowship. JLG thanks Conacyt for grant 237045, and AV thanks Conacyt for grant Fronteras 867.
文摘A global and local charge transfer partitioning model,based on the cornerstone theory developed by Robert G.Parr and Robert G.Pearson,which introduces two charge transfer channels(one for accepting electrons(electrophilic) and another for donating(nucleophilic)),is applied to the reaction of a set of indoles with 4,6-dinitrobenzofuroxan.The global analysis indicates that the prevalent electron transfer mechanism in the reaction is a nucleophilic one on the indoles,i.e.,the indoles under consideration transfer electrons to 4,6-dinitrobenzofuroxan.Evaluating the reactivity descriptorswith exchange-correlation functionals including exact exchange(global hybrids) yields slightly better correlations than those obtained with generalized gradient-approximated functionals;however,the trends are preserved.Comparing the trend obtained with the number of electrons donated by the indoles,and predicted by the partitioning model,with that observed experimentally based on the measured rate constants,we propose that the number of electrons transferred through this channel can be used as a nucleophilicity scale to order the reactivity of indoles towards 4,6-dinitrobenzofuroxan.This approach to obtain reactivity scales has the advantage of depending on the intrinsic properties of the two reacting species;therefore,it opens the possibility that the same group of molecules may show different reactivity trends depending on the species with which they are reacting.The local model allows systematic incorporation of the reactive atoms based on the their decreasing condensed Fukui functions,and the correlations obtained by increasing the number of reactive atoms participating in the local analysis of the transferred nucleophilic charge improve,reaching an optimal correlation,which in the present case indicates keeping three atoms from the indoles and two from 4,6-dinitrobenzofuroxan.The atoms selected by this procedure provide valuable information about the local reactivity of the indoles.We further show that this information about the most reactive atoms on each reactant,combined with the spatial distribution of the nucleophilic and electrophilic Fukui functions of both reactants,allows one to propose non-trivial candidates of starting geometries for the search of the transition state structures present in these reactions.
