Dear Editor,This letter focuses on how an attacker can design suitable improved zero-dynamics (ZD) attack signal based on state estimates of target system. Improved ZD attack is to change zero dynamic gain matrix of a...Dear Editor,This letter focuses on how an attacker can design suitable improved zero-dynamics (ZD) attack signal based on state estimates of target system. Improved ZD attack is to change zero dynamic gain matrix of attack signal to a matrix with determinant greater than 1.展开更多
In actual power systems,most of the high-voltage buses of the transformers are zero injection buses without load or generation.Power injections into these buses are strictly 0,so based on Kirchhoff's current law(K...In actual power systems,most of the high-voltage buses of the transformers are zero injection buses without load or generation.Power injections into these buses are strictly 0,so based on Kirchhoff's current law(KCL),equality constraints should be used to handle these buses in a state estimation model.It is a challenge to ensure that these zero injection constraints can be strictly satisfied without losing computational efficiency.展开更多
In this paper, for a class of high-order stochastic nonlinear systems with zero dynamics which are neither necessarily feedback linearizable nor affine in the control input, the problem of state feedback stabilization...In this paper, for a class of high-order stochastic nonlinear systems with zero dynamics which are neither necessarily feedback linearizable nor affine in the control input, the problem of state feedback stabilization is investigated for the first time. Under some weaker assumptions, a smooth state feedback controller is designed, which ensures that the closed-loop system has an almost surely unique solution on [0,∞）, the equilibrium at the origin of the closed-loop system is globally asymptotically stable in probability, and all the states can be regulated to the origin almost surely. A simulation example demonstrates the control scheme.展开更多
Mani observed zero-registance states similar to those quantum-Hall-effect states in GaAs/AlGaAs but without the Hall resistance plateaus upon the application of radiations [R. G. Mani, Physica E 22, 1 (2004)]. An inte...Mani observed zero-registance states similar to those quantum-Hall-effect states in GaAs/AlGaAs but without the Hall resistance plateaus upon the application of radiations [R. G. Mani, Physica E 22, 1 (2004)]. An interpretation is presented. The applied radiation excites “holes”. The condensed composite (c)-bosons formed in the excited channel create a superconducting state with an energy gap. The supercondensate suppresses the non-condensed c-bosons at the higher energy, but it cannot suppress the c-fermions in the base channel, and the small normal current accompanied by the Hall field yeilds a B-linear Hall resistivity.展开更多
The unique wave-manipulation capabilities of zero-index metamaterials(ZIMs)offer a new opportunity for realizing bound states in the continuum(BICs).However,the relationship between anomalous scattering and BICs remai...The unique wave-manipulation capabilities of zero-index metamaterials(ZIMs)offer a new opportunity for realizing bound states in the continuum(BICs).However,the relationship between anomalous scattering and BICs remains underexplored when parity–time(PT)symmetry is introduced.In this work,we demonstrate that a BIC splits into a pair of lasing modes carrying opposite topological charges by introducing PT symmetry through gain-loss cylinders embedded in ZIM layers.Theoretical analysis and numerical simulations reveal that lasing and unidirectional transparency phenomena result from the singularities and exceptional points of the scattering matrix.Moreover,exceptional points can be tuned via propagation phase modulation in the air gap,and their coalescence produces quasi-BICs with symmetric responses.This work provides a framework for manipulating BICs and topological lasing modes in non-Hermitian systems,offering new insights for designing non-Hermitian photonic devices.展开更多
We investigate zero-sound modes in nuclear matter and neutron star matter using the relativistic random phase approximation(RRPA),focusing on the role of a light vector U boson in stiffening the nuclear equation of st...We investigate zero-sound modes in nuclear matter and neutron star matter using the relativistic random phase approximation(RRPA),focusing on the role of a light vector U boson in stiffening the nuclear equation of state(EOS).The occurrence of zero sound is closely linked to the stiffness of the nuclear EOS.The additional vector repulsive potential induced by the U boson results in the occurrence of zero sound at high densities in models with a soft high-density EOS,and the density range for zero sound extends to higher densities with larger coupling strength of the U boson.This confirms the unambiguous role of stiffening the high-density EOS in resulting in the appearance of zero sound.展开更多
Majorana zero modes(MZMs) are Majorana-fermion-like quasiparticles existing in crystals or hybrid platforms with topologically non-trivial electronic structures. They obey non-Abelian braiding statistics and are consi...Majorana zero modes(MZMs) are Majorana-fermion-like quasiparticles existing in crystals or hybrid platforms with topologically non-trivial electronic structures. They obey non-Abelian braiding statistics and are considered promising to realize topological quantum computing. Discovery of MZM in the vortices of the iron-based superconductors(IBSs)has recently fueled the Majorana research in a way which not only removes the material barrier requiring construction of complicated hybrid artificial structures, but also enables observation of pure MZMs under higher temperatures. So far,MZMs have been observed in iron-based superconductors including FeTe_(0.55)Se_(0.45),(Li_(0.84)Fe_(0.16))OHFe Se, Ca KFe_(4)As_(4),and Li Fe As. In this topical review, we present an overview of the recent STM studies on the MZMs in IBSs. We start with the observation of MZMs in the vortices in FeTe_(0.55)Se_(0.45)and discuss the pros and cons of FeTe_(0.55)Se_(0.45) compared with other platforms. We then review the following up discovery of MZMs in vortices of Ca KFe_(4)As_(4), impurity-assisted vortices of Li Fe As, and quantum anomalous vortices in FeTe_(0.55)Se_(0.45), illustrating the pathway of the developments of MZM research in IBSs. Finally, we give perspective on future experimental works in this field.展开更多
The problems of long-range interaction and associated questions on entangled states are reconsidered in terms of a recently developed revised quantum electrodynamic theory by the author, as being applied to subatomic ...The problems of long-range interaction and associated questions on entangled states are reconsidered in terms of a recently developed revised quantum electrodynamic theory by the author, as being applied to subatomic systems. There are indications that the theories of relativity and quantum mechanics do not necessarily have to be in conflict. But more investigations are required for a full understanding to be obtained on these problems.展开更多
Both, the dilemma to find a quantum field theory consistent with Einstein’s law of relativity and the problem to describe existing particles as bound states of matter has been solved by calculating bound state matrix...Both, the dilemma to find a quantum field theory consistent with Einstein’s law of relativity and the problem to describe existing particles as bound states of matter has been solved by calculating bound state matrix elements from a dual fermion-boson Lagrangian. In this formalism, the fermion binding energies are compensated by boson energies, indicating that particles can be generated out of the vacuum. This yields quantitative solutions for various mesons ω (0.78 GeV) - Υ (9.46 GeV) and all leptons e, μ and τ, with uncertainties in the extracted properties of less than 1‰. For transparency, a Web-page with the address htpps://h2909473.stratoserver.net has been constructed, where all calculations can be run on line and also the underlying fortran source code can be inspected.展开更多
Solid-state polymer sodium–metal batteries(SPSMBs)are considered an essential solution to the safety issues and low energy density of conventional liquid electrolyte sodium-ion batteries.The unstable cathode electrol...Solid-state polymer sodium–metal batteries(SPSMBs)are considered an essential solution to the safety issues and low energy density of conventional liquid electrolyte sodium-ion batteries.The unstable cathode electrolyte interface(CEI)caused by the volume expansion of the cathode hinders the construction of high-energy and long-life SPSMBs.Herein,a quasi-zero-strain layered Nb_(4)P_(2)S_(21) cathode and a localized high-concentration solid-state polymer electrolyte(LHC-SPE)are designed to address the interfacial issues in SPSMBs.The fabricated Na|SPE|Nb_(4)P_(2)S_(21) SPSMBs present a high capacity(315 mA h g^(−1) at 0.5C),high-rate performance(167 mA h g^(−1) at 10C),and good cycling performance(294 mA h g^(−1) at 1C after 150 cycles).Moreover,a high energy density of 500 W h kg^(−1) and a high power density of 2.7 kW kg^(−1) can be achieved,which are superior to the electrochemical performance of the Nb_(4)P_(2)S_(21) cathode in a liquid electrolyte(LE).Further cyclic voltammetry(CV)and in situ Raman characterization studies reveal a dual-redox mechanism based on Nb_(4+)/Nb^(3+)and S^(−)/S^(2−),and in situ XRD manifests quasi-zero-strain sodium insertion behavior.Moreover,a NaF-rich CEI is revealed from the X-ray photoelectron spectroscopy(XPS)results of the cycled electrode.This study has significant implications for the development of SPSMBs with high energy and a long cycling life.展开更多
针对具有非最小相位特性的单电感双输出Buck-Boost变换器(SIDO Buck-Boost)输出两支路存在严重的交叉影响、控制困难以及系统暂态性能差等问题,提出一种基于扩张状态观测器(extended state observer,ESO)的主路微分平坦控制(differentia...针对具有非最小相位特性的单电感双输出Buck-Boost变换器(SIDO Buck-Boost)输出两支路存在严重的交叉影响、控制困难以及系统暂态性能差等问题,提出一种基于扩张状态观测器(extended state observer,ESO)的主路微分平坦控制(differential flatness based control,DFBC)和支路改进双闭环自抗扰控制(active disturbance rejection controller,ADRC)的控制策略.首先,根据主路微分平坦理论,在主路控制中设计微分平坦控制器,并对微分平坦系统进行误差反馈;设计ESO对主路的扰动项进行观测,将观测后的状态量反馈到微分平坦控制器中.其次,针对支路存在耦合以及右半平面零点的问题,设计改进型双闭环ADRC进行系统解耦,其中,电流内环选取基于模型补偿和前馈补偿的ADRC,电压外环选取普通ADRC,然后,利用Lyapunov理论证明系统的稳定性.最后,在Matlab/Simulink平台中搭建了仿真模型,并基于HIL搭建了实验平台.仿真及实验结果表明:所提控制策略减小了输出两支路之间的交叉影响,解决了非最小相位系统控制困难的问题,提高了系统的暂态响应性能.展开更多
基金supported in part by the National Natural Science Foundation of China(61873106,62303109)Start-Up Research Fund of Southeast University(RF1028623002)Shenzhen Science and Technology Program(JCYJ20230807114609019)
文摘Dear Editor,This letter focuses on how an attacker can design suitable improved zero-dynamics (ZD) attack signal based on state estimates of target system. Improved ZD attack is to change zero dynamic gain matrix of attack signal to a matrix with determinant greater than 1.
文摘In actual power systems,most of the high-voltage buses of the transformers are zero injection buses without load or generation.Power injections into these buses are strictly 0,so based on Kirchhoff's current law(KCL),equality constraints should be used to handle these buses in a state estimation model.It is a challenge to ensure that these zero injection constraints can be strictly satisfied without losing computational efficiency.
基金Program for New Century Excellent Talents in University of China (NCET-05-0607)National Natural Science Fou-ndation of China (No.60774010)Project for Fundamental Research of Natural Sciences in Universities of Jingsu Province (No.07KJB510114)
文摘In this paper, for a class of high-order stochastic nonlinear systems with zero dynamics which are neither necessarily feedback linearizable nor affine in the control input, the problem of state feedback stabilization is investigated for the first time. Under some weaker assumptions, a smooth state feedback controller is designed, which ensures that the closed-loop system has an almost surely unique solution on [0,∞）, the equilibrium at the origin of the closed-loop system is globally asymptotically stable in probability, and all the states can be regulated to the origin almost surely. A simulation example demonstrates the control scheme.
文摘Mani observed zero-registance states similar to those quantum-Hall-effect states in GaAs/AlGaAs but without the Hall resistance plateaus upon the application of radiations [R. G. Mani, Physica E 22, 1 (2004)]. An interpretation is presented. The applied radiation excites “holes”. The condensed composite (c)-bosons formed in the excited channel create a superconducting state with an energy gap. The supercondensate suppresses the non-condensed c-bosons at the higher energy, but it cannot suppress the c-fermions in the base channel, and the small normal current accompanied by the Hall field yeilds a B-linear Hall resistivity.
基金supported by the National Natural Science Foundation of China(Grant Nos.12504361,12274313,and 62465005)the Natural Science Foundation of Guangxi(Grant No.2025GXNSFBA069179)the Guangxi Colleges and Universities Young and Middle-aged Teachers’Basic Scientific Research Ability Enhancement Project(Grant No.2025KY0093)。
文摘The unique wave-manipulation capabilities of zero-index metamaterials(ZIMs)offer a new opportunity for realizing bound states in the continuum(BICs).However,the relationship between anomalous scattering and BICs remains underexplored when parity–time(PT)symmetry is introduced.In this work,we demonstrate that a BIC splits into a pair of lasing modes carrying opposite topological charges by introducing PT symmetry through gain-loss cylinders embedded in ZIM layers.Theoretical analysis and numerical simulations reveal that lasing and unidirectional transparency phenomena result from the singularities and exceptional points of the scattering matrix.Moreover,exceptional points can be tuned via propagation phase modulation in the air gap,and their coalescence produces quasi-BICs with symmetric responses.This work provides a framework for manipulating BICs and topological lasing modes in non-Hermitian systems,offering new insights for designing non-Hermitian photonic devices.
基金Supported in part by the National Natural Science Foundation of China(12375112)。
文摘We investigate zero-sound modes in nuclear matter and neutron star matter using the relativistic random phase approximation(RRPA),focusing on the role of a light vector U boson in stiffening the nuclear equation of state(EOS).The occurrence of zero sound is closely linked to the stiffness of the nuclear EOS.The additional vector repulsive potential induced by the U boson results in the occurrence of zero sound at high densities in models with a soft high-density EOS,and the density range for zero sound extends to higher densities with larger coupling strength of the U boson.This confirms the unambiguous role of stiffening the high-density EOS in resulting in the appearance of zero sound.
基金supported by the Ministry of Science and Technology of China (Grant No. 2019YFA0308500)the Chinese Academy of Sciences (Grant Nos. XDB28000000 and YSBR-003)。
文摘Majorana zero modes(MZMs) are Majorana-fermion-like quasiparticles existing in crystals or hybrid platforms with topologically non-trivial electronic structures. They obey non-Abelian braiding statistics and are considered promising to realize topological quantum computing. Discovery of MZM in the vortices of the iron-based superconductors(IBSs)has recently fueled the Majorana research in a way which not only removes the material barrier requiring construction of complicated hybrid artificial structures, but also enables observation of pure MZMs under higher temperatures. So far,MZMs have been observed in iron-based superconductors including FeTe_(0.55)Se_(0.45),(Li_(0.84)Fe_(0.16))OHFe Se, Ca KFe_(4)As_(4),and Li Fe As. In this topical review, we present an overview of the recent STM studies on the MZMs in IBSs. We start with the observation of MZMs in the vortices in FeTe_(0.55)Se_(0.45)and discuss the pros and cons of FeTe_(0.55)Se_(0.45) compared with other platforms. We then review the following up discovery of MZMs in vortices of Ca KFe_(4)As_(4), impurity-assisted vortices of Li Fe As, and quantum anomalous vortices in FeTe_(0.55)Se_(0.45), illustrating the pathway of the developments of MZM research in IBSs. Finally, we give perspective on future experimental works in this field.
文摘The problems of long-range interaction and associated questions on entangled states are reconsidered in terms of a recently developed revised quantum electrodynamic theory by the author, as being applied to subatomic systems. There are indications that the theories of relativity and quantum mechanics do not necessarily have to be in conflict. But more investigations are required for a full understanding to be obtained on these problems.
文摘Both, the dilemma to find a quantum field theory consistent with Einstein’s law of relativity and the problem to describe existing particles as bound states of matter has been solved by calculating bound state matrix elements from a dual fermion-boson Lagrangian. In this formalism, the fermion binding energies are compensated by boson energies, indicating that particles can be generated out of the vacuum. This yields quantitative solutions for various mesons ω (0.78 GeV) - Υ (9.46 GeV) and all leptons e, μ and τ, with uncertainties in the extracted properties of less than 1‰. For transparency, a Web-page with the address htpps://h2909473.stratoserver.net has been constructed, where all calculations can be run on line and also the underlying fortran source code can be inspected.
基金supported by the Natural Science Foundation of Jiangxi Province(GJJ211320,20224BAB204002)the Jingdezhen Science and Technology Bureau(20212GYZD009-15)+3 种基金the National Key Research and Development Program of China(Grant No.2019YFA0210600)the Science and Technology Commission of Shanghai Municipality(23DZ1200800,22ZR1471300)the National Natural Science Foundation of China(Grant No.51922103 and 51972326)support from the Analytical Instrumentation Center(#SPST-AIC10112914),SPST,ShanghaiTech.
文摘Solid-state polymer sodium–metal batteries(SPSMBs)are considered an essential solution to the safety issues and low energy density of conventional liquid electrolyte sodium-ion batteries.The unstable cathode electrolyte interface(CEI)caused by the volume expansion of the cathode hinders the construction of high-energy and long-life SPSMBs.Herein,a quasi-zero-strain layered Nb_(4)P_(2)S_(21) cathode and a localized high-concentration solid-state polymer electrolyte(LHC-SPE)are designed to address the interfacial issues in SPSMBs.The fabricated Na|SPE|Nb_(4)P_(2)S_(21) SPSMBs present a high capacity(315 mA h g^(−1) at 0.5C),high-rate performance(167 mA h g^(−1) at 10C),and good cycling performance(294 mA h g^(−1) at 1C after 150 cycles).Moreover,a high energy density of 500 W h kg^(−1) and a high power density of 2.7 kW kg^(−1) can be achieved,which are superior to the electrochemical performance of the Nb_(4)P_(2)S_(21) cathode in a liquid electrolyte(LE).Further cyclic voltammetry(CV)and in situ Raman characterization studies reveal a dual-redox mechanism based on Nb_(4+)/Nb^(3+)and S^(−)/S^(2−),and in situ XRD manifests quasi-zero-strain sodium insertion behavior.Moreover,a NaF-rich CEI is revealed from the X-ray photoelectron spectroscopy(XPS)results of the cycled electrode.This study has significant implications for the development of SPSMBs with high energy and a long cycling life.
文摘针对具有非最小相位特性的单电感双输出Buck-Boost变换器(SIDO Buck-Boost)输出两支路存在严重的交叉影响、控制困难以及系统暂态性能差等问题,提出一种基于扩张状态观测器(extended state observer,ESO)的主路微分平坦控制(differential flatness based control,DFBC)和支路改进双闭环自抗扰控制(active disturbance rejection controller,ADRC)的控制策略.首先,根据主路微分平坦理论,在主路控制中设计微分平坦控制器,并对微分平坦系统进行误差反馈;设计ESO对主路的扰动项进行观测,将观测后的状态量反馈到微分平坦控制器中.其次,针对支路存在耦合以及右半平面零点的问题,设计改进型双闭环ADRC进行系统解耦,其中,电流内环选取基于模型补偿和前馈补偿的ADRC,电压外环选取普通ADRC,然后,利用Lyapunov理论证明系统的稳定性.最后,在Matlab/Simulink平台中搭建了仿真模型,并基于HIL搭建了实验平台.仿真及实验结果表明:所提控制策略减小了输出两支路之间的交叉影响,解决了非最小相位系统控制困难的问题,提高了系统的暂态响应性能.
