Structured microgrids(SμGs)and Flexible electronic large power transformers(FeLPTs)are emerging as two essential technologies for renewable energy integration,flexible power transmission,and active control.SμGs prov...Structured microgrids(SμGs)and Flexible electronic large power transformers(FeLPTs)are emerging as two essential technologies for renewable energy integration,flexible power transmission,and active control.SμGs provide the integration of renewable energy and storage to balance the energy demand and supply as needed for a given system design.FeLPT’s flexibility for processing,control,and re-configurability offers the capability for flexible transmission for effective flow control and enable SμGs connectivity while still keeping multiscale system level control.Early adaptors for combined heat and power have demonstrated significant economic benefits while reducing environmental foot prints.They bring tremendous benefits to utility companies also.With storage and active control capabilities,a 300-percent increase in bulk transmission and distribution lines are possible without having to increase capacity.SμGs and FeLPTs will also enable the utility industry to be better prepared for the emerging large increase in base load demand from electric transportation and data centers.This is a win-win-win situation for the consumer,the utilities(grid operators),and the environment.SμGs and FeLPTs provide value in power substation,energy surety,reliability,resiliency,and security.It is also shown that the initial cost associated with SμG and FeLPTs deployment can be easily offset with reduced operating cost,which in turn reduces the total life-cycle cost by 33%to 67%.展开更多
Addressing the challenges posed by the nonlinear and non-stationary vibrations in rotating machinery,where weak fault characteristic signals hinder accurate fault state representation,we propose a novel feature extrac...Addressing the challenges posed by the nonlinear and non-stationary vibrations in rotating machinery,where weak fault characteristic signals hinder accurate fault state representation,we propose a novel feature extraction method that combines the Flexible Analytic Wavelet Transform(FAWT)with Nonlinear Quantum Permutation Entropy.FAWT,leveraging fractional orders and arbitrary scaling and translation factors,exhibits superior translational invariance and adjustable fundamental oscillatory characteristics.This flexibility enables FAWT to provide well-suited wavelet shapes,effectively matching subtle fault components and avoiding performance degradation associated with fixed frequency partitioning and low-oscillation bases in detecting weak faults.In our approach,gearbox vibration signals undergo FAWT to obtain sub-bands.Quantum theory is then introduced into permutation entropy to propose Nonlinear Quantum Permutation Entropy,a feature that more accurately characterizes the operational state of vibration simulation signals.The nonlinear quantum permutation entropy extracted from sub-bands is utilized to characterize the operating state of rotating machinery.A comprehensive analysis of vibration signals from rolling bearings and gearboxes validates the feasibility of the proposed method.Comparative assessments with parameters derived from traditional permutation entropy,sample entropy,wavelet transform(WT),and empirical mode decomposition(EMD)underscore the superior effectiveness of this approach in fault detection and classification for rotating machinery.展开更多
Flexible design is one of the most significant features of metal-organic frameworks(MOFs)in that it can improve the efficiency of MOFs in storage,separation,sensing,and other applications.Herein,we reported a facile s...Flexible design is one of the most significant features of metal-organic frameworks(MOFs)in that it can improve the efficiency of MOFs in storage,separation,sensing,and other applications.Herein,we reported a facile strategy to perform the flexible crystalline transformation of MOF polyhedra into their crisp-like derivatives.A mild hydrothermal process involved a crystalline change from ZIF-7 to Zn_(2)(bim)_(4)and a morphological change from an individual polyhedron to a string of nanosheets.Based on the crisp-like morphology which possessed abundant accessible active sites,composites such as Zn_(2)(bim)_(4)@ZnS and Zn_(2)(bim)_(4)@CoS could be obtained by further sulfidation and applied in oxygen evolution reactions(OERs)with a lower overpotential(330 mV)and good stability compared with a commercial IrO_(2)electrode.The well-organized Zn_(2)(bim)_(4)nanosheets with crisp-like morphology demonstrate an interesting crystalline transformation route to construct complicated nanostructures which are hardly achievable by direct synthesis,showing great promise for designing functional derived materials from MOFs.展开更多
文摘Structured microgrids(SμGs)and Flexible electronic large power transformers(FeLPTs)are emerging as two essential technologies for renewable energy integration,flexible power transmission,and active control.SμGs provide the integration of renewable energy and storage to balance the energy demand and supply as needed for a given system design.FeLPT’s flexibility for processing,control,and re-configurability offers the capability for flexible transmission for effective flow control and enable SμGs connectivity while still keeping multiscale system level control.Early adaptors for combined heat and power have demonstrated significant economic benefits while reducing environmental foot prints.They bring tremendous benefits to utility companies also.With storage and active control capabilities,a 300-percent increase in bulk transmission and distribution lines are possible without having to increase capacity.SμGs and FeLPTs will also enable the utility industry to be better prepared for the emerging large increase in base load demand from electric transportation and data centers.This is a win-win-win situation for the consumer,the utilities(grid operators),and the environment.SμGs and FeLPTs provide value in power substation,energy surety,reliability,resiliency,and security.It is also shown that the initial cost associated with SμG and FeLPTs deployment can be easily offset with reduced operating cost,which in turn reduces the total life-cycle cost by 33%to 67%.
基金supported financially by FundamentalResearch Program of Shanxi Province(No.202103021223056).
文摘Addressing the challenges posed by the nonlinear and non-stationary vibrations in rotating machinery,where weak fault characteristic signals hinder accurate fault state representation,we propose a novel feature extraction method that combines the Flexible Analytic Wavelet Transform(FAWT)with Nonlinear Quantum Permutation Entropy.FAWT,leveraging fractional orders and arbitrary scaling and translation factors,exhibits superior translational invariance and adjustable fundamental oscillatory characteristics.This flexibility enables FAWT to provide well-suited wavelet shapes,effectively matching subtle fault components and avoiding performance degradation associated with fixed frequency partitioning and low-oscillation bases in detecting weak faults.In our approach,gearbox vibration signals undergo FAWT to obtain sub-bands.Quantum theory is then introduced into permutation entropy to propose Nonlinear Quantum Permutation Entropy,a feature that more accurately characterizes the operational state of vibration simulation signals.The nonlinear quantum permutation entropy extracted from sub-bands is utilized to characterize the operating state of rotating machinery.A comprehensive analysis of vibration signals from rolling bearings and gearboxes validates the feasibility of the proposed method.Comparative assessments with parameters derived from traditional permutation entropy,sample entropy,wavelet transform(WT),and empirical mode decomposition(EMD)underscore the superior effectiveness of this approach in fault detection and classification for rotating machinery.
基金supported by the National Natural Science Foundation of China(21971114)the Jiangsu Provincial Funds for Natural Science Foundation(BK20200090)the China Postdoctoral Science Foundation(2021M691552).
文摘Flexible design is one of the most significant features of metal-organic frameworks(MOFs)in that it can improve the efficiency of MOFs in storage,separation,sensing,and other applications.Herein,we reported a facile strategy to perform the flexible crystalline transformation of MOF polyhedra into their crisp-like derivatives.A mild hydrothermal process involved a crystalline change from ZIF-7 to Zn_(2)(bim)_(4)and a morphological change from an individual polyhedron to a string of nanosheets.Based on the crisp-like morphology which possessed abundant accessible active sites,composites such as Zn_(2)(bim)_(4)@ZnS and Zn_(2)(bim)_(4)@CoS could be obtained by further sulfidation and applied in oxygen evolution reactions(OERs)with a lower overpotential(330 mV)and good stability compared with a commercial IrO_(2)electrode.The well-organized Zn_(2)(bim)_(4)nanosheets with crisp-like morphology demonstrate an interesting crystalline transformation route to construct complicated nanostructures which are hardly achievable by direct synthesis,showing great promise for designing functional derived materials from MOFs.
