This paper firstly presents an equivalent coupling circuit modeling of multi-parallel inverters in microgrid operating in grid-connected mode. By using the model, the coupling resonance phenomena are explicitly invest...This paper firstly presents an equivalent coupling circuit modeling of multi-parallel inverters in microgrid operating in grid-connected mode. By using the model, the coupling resonance phenomena are explicitly investigated through the mathematical approach, and the intrinsic and extrinsic resonances exist widely in microgrid.Considering the inverter own reference current, other inverters reference current, and grid harmonic voltage, the distributions of resonance peaks with the growth in the number of inverters are obtained. Then, an active damping control parameter design method is proposed to attenuate coupling resonance, and the most salient feature is that the optimal range of the damping parameter can be easily located through an initiatively graphic method. Finally,simulations and experiments verify the validity of the proposed modeling and method.展开更多
A nonlinear model of a low pressure cylinder-generator rotor system is presented to study sub-synchronous resonance and combined resonance. Analytical results are obtained by an averaging method. Transition sets and b...A nonlinear model of a low pressure cylinder-generator rotor system is presented to study sub-synchronous resonance and combined resonance. Analytical results are obtained by an averaging method. Transition sets and bifurcation diagrams are obtained based on the singularity theory for the two-state variable system. The bifurcation characteristics are analyzed to provide a basis for the optimal design and fault diagnosis of the rotor system. Finally, the theoretical results are verified with the numerical results.展开更多
Potential energy surfaces(PESs), vibrational frequencies, and infrared spectra are calculated for NF_(3)^(+) using ab initio calculations, based on UCCSD(T)/cc-p VTZ combined with vibrational configuration interaction...Potential energy surfaces(PESs), vibrational frequencies, and infrared spectra are calculated for NF_(3)^(+) using ab initio calculations, based on UCCSD(T)/cc-p VTZ combined with vibrational configuration interaction(VCI). Based on an iterative algorithm, the surfaces(SURF) program adds automatic points to the lattice representation of the potential function, the one-dimensional and two-dimensional PESs are calculated after reaching a convergence threshold, finally the smooth image of the potential energy surface is fitted. The PESs accurately account for the interaction between the different modes, with the mode q_(6) symmetrical stretching vibrations having the greatest effect on the potential energy change of the whole system throughout the potential energy surface shift. The anharmonic frequencies are obtained when the VCI matrix is diagonalized. Fundamental frequencies, overtones, and combination bands of NF_(3)^(+) are calculated, which generate the degenerate phenomenon between their frequencies. Finally, the calculated anharmonic frequency is used to plot the infrared spectra.Modal antisymmetric stretching ν_(5) and symmetric stretching ν_(6) exhibit a phenomenon of large-intensity borrowing. This study can provide data to support the characterization in the laboratory.展开更多
The method of numerical analysis is employed to study the resonance mechanism of the lumped parameter system model for acoustic mine detection. Based on the basic principle of the acoustic resonance technique for mine...The method of numerical analysis is employed to study the resonance mechanism of the lumped parameter system model for acoustic mine detection. Based on the basic principle of the acoustic resonance technique for mine detection and the characteristics of low-frequency acoustics, the “soil-mine” system could be equivalent to a damping “mass-spring” resonance model with a lumped parameter analysis method. The dynamic simulation software, Adams, is adopted to analyze the lumped parameter system model numerically. The simulated resonance frequency and anti-resonance frequency are 151 Hz and 512 Hz respectively, basically in agreement with the published resonance frequency of 155 Hz and anti-resonance frequency of 513 Hz, which were measured in the experiment. Therefore, the technique of numerical simulation is validated to have the potential for analyzing the acoustic mine detection model quantitatively. The influences of the soil and mine parameters on the resonance characteristics of the soil–mine system could be investigated by changing the parameter setup in a flexible manner.展开更多
It has been reported that electron-rotation coupling plays a significant role in diatomic nuclear dynamics induced by intense VUV pulses [Phys. Rev. A 102(2020) 033114;Phys. Rev. Res. 2(2020) 043348]. As a further ste...It has been reported that electron-rotation coupling plays a significant role in diatomic nuclear dynamics induced by intense VUV pulses [Phys. Rev. A 102(2020) 033114;Phys. Rev. Res. 2(2020) 043348]. As a further step, we present here investigations of the electron-rotation coupling effect in the presence of Auger decay channel for core-excited molecules, based on theoretical modeling of the total electron yield(TEY), resonant Auger scattering(RAS) and x-ray absorption spectra(XAS) for two showcases of CO and CH^(+) molecules excited by resonant intense x-ray pulses. The Wigner D-functions and the universal transition dipole operators are introduced to include the electron-rotation coupling for the core-excitation process. It is shown that with the pulse intensity up to 10^(16) W/cm^(2), no sufficient influence of the electron-rotation coupling on the TEY and RAS spectra can be observed. This can be explained by a suppression of the induced electron-rotation dynamics due to the fast Auger decay channel, which does not allow for effective Rabi cycling even at extreme field intensities,contrary to transitions in optical or VUV range. For the case of XAS, however, relative errors of about 10% and 30% are observed for the case of CO and CH^(+), respectively, when the electron-rotation coupling is neglected.It is concluded that conventional treatment of the photoexcitation, neglecting the electron-rotation coupling,can be safely and efficiently employed to study dynamics at the x-ray transitions by means of electron emission spectroscopy, yet the approximation breaks down for nonlinear processes as stimulated emission, especially for systems with light atoms.展开更多
We propose an effective mechanism to couple superconducting charge and flux qubits by using a quantized nanomechanical resonator. The coupling between the charge and flux qubits can be controlled by the external flux ...We propose an effective mechanism to couple superconducting charge and flux qubits by using a quantized nanomechanical resonator. The coupling between the charge and flux qubits can be controlled by the external flux of the charge qubit. Under the strong coupling limR, an iSWAP gate can be generated by this scheme. The experimental feasibility in our scheme is also presented.展开更多
We developed a biosensor that is capable for simultaneous surface plasmon resonance(SPR)sensing and hyperspectral fuores cence analysis in this paper.A symmetrical metal-dielectric slabscheme is employed for the excit...We developed a biosensor that is capable for simultaneous surface plasmon resonance(SPR)sensing and hyperspectral fuores cence analysis in this paper.A symmetrical metal-dielectric slabscheme is employed for the excitation of coupled plasnon waveguide resonance(CPWR)in thepresent work.Resonance bet ween surface plasmon mode and the guided waveguide mode gen-erates narrower full width half-maximum of the refective curves which leads to increased pre.cision for the determination of refractive index over conventional SPR sensors.In addition,CPWR also fers longer surface propagation depths and higher surface electric field strengthsthat enable the excitation of fluorescence with hyperspectral technique to maintain an appreci-able signal-to-noise ratio.The refractive index information obtained from SPR sensing and thechemical properties obt ained through hyperspectral fluorescence analysis confirm each other toexclude false-positive or false-negative cases.The sensor provides a comprehensive understandingof the biological events on the sensor chips.展开更多
We discuss the dynamical behavior of a chemical network arising from the coupling of two Brusselators established by the relationship between products and substrates. Our interest is to investigate the coherence reson...We discuss the dynamical behavior of a chemical network arising from the coupling of two Brusselators established by the relationship between products and substrates. Our interest is to investigate the coherence resonance (CR) phenomena caused by noise for a coupled Brusselator model in the vicinity of the Hopf bifurcation, which can be determined by the signM-to-noise ratio (SNR). The CR in two coupled Brusselators will be considered in the presence of the Gaussian colored noise and two uncorrelated Gaussian white noises. Simulation results show that, for the case of single noise, the SNR characterizing the degree of temporal regularity of coupled model reaches a maximum value at some optimal noise levels, and the noise intensity can enhance the CR phenomena of both subsystems with a similar trend but in different resonance degrees. Meanwhile, effects of noise intensities on CR of the second subsystem are opposite for the systems under we find that CR might be a general phenomenon in coupled two uncorrelated Gaussian white noises. Moreover, systems.展开更多
In this study, we observe a strong inverse magnetoelectric coupling in Fe52.5Co22.5B25.0/PZN-PT multiferroic heterostructure, which produces large electric field(E-field) tunability of microwave magnetic properties....In this study, we observe a strong inverse magnetoelectric coupling in Fe52.5Co22.5B25.0/PZN-PT multiferroic heterostructure, which produces large electric field(E-field) tunability of microwave magnetic properties. With the increase of the E-field from 0 to 8 kV/cm, the magnetic anisotropy field Heffis dramatically enhanced from 169 to 600 Oe, which further leads to a significant enhancement of ferromagnetic resonance frequency from 4.57 to 8.73 GHz under zero bias magnetic field, and a simultaneous decrease of the damping constant α from 0.021 to 0.0186. These features demonstrate that this multiferroic composite is a promising candidate for fabricating E-field tunable microwave components.展开更多
Excited states of lnAs quantum dots (QDs) can be energetically coupled with the confined level of OaAs quantum wells (QWs) in a thin-barrier resonant tunneling diode (RTD). Single charge variation in the coupled...Excited states of lnAs quantum dots (QDs) can be energetically coupled with the confined level of OaAs quantum wells (QWs) in a thin-barrier resonant tunneling diode (RTD). Single charge variation in the coupled QD can effectively switch on/off the resonant tunneling current passing through RTD, not only for emcient single-photon detection but also for photon-number-resolving detection. We present the study of the Q,D-QW coupling effect in the quantum dot coupled resonant tunneling diode (QD-cRTD) and figure out important factors for further improving the detector performance.展开更多
According to the plasmon hybridization theory, the plasmon resonance characteristics of the gold nanocrescent/nanoring(NCNR) structure are systematically investigated by the finite element method. It is found that the...According to the plasmon hybridization theory, the plasmon resonance characteristics of the gold nanocrescent/nanoring(NCNR) structure are systematically investigated by the finite element method. It is found that the extinction spectra of NCNR structure exhibit multiple plasmon resonance peaks, which could be attributed to the result of the plasmon couplings between the multipolar plasmon modes of nanocrescent and the dipolar, quadrupolar, hexapolar, octupolar,decapolar plasmon modes of nanoring. By changing the geometric parameters, the intense and separate multiple plasmon resonance peaks are obtained and can be tuned in a wide wavelength range. It is further found that the plasmon coupling induces giant multipole electric field enhancements around the tips of the nanocrescent. The tunable and intense multiple plasmon resonances of NCNR structure may provide effective applications in multiplex biological sensing.展开更多
Magnetically coupled resonant technology is a novel method for solving the breakpoint locating of power grounding grid.But the method can only detect breakpoints of a single mesh grounding grid at present.In this pape...Magnetically coupled resonant technology is a novel method for solving the breakpoint locating of power grounding grid.But the method can only detect breakpoints of a single mesh grounding grid at present.In this paper,a magnetically coupled resonant detection method for four-hole grounding grid breakpoint is proposed.Firstly,the equivalent circuit model of the four mesh grounding grid with two types of breakpoints,namely edge branch and intermediate branch,is established.The input impedance and phase angle of the system are obtained by analyzing the equivalent capacitance and equivalent resistance in the model.Secondly,the magnetically coupled resonant physical process of grounding grid faults is solved via HFSS software.The magnetic field intensity and phase frequency characteristic curves of four mesh holes with different branches and positions of breakpoints and different corrosion degrees are studied,and an experimental system is built to verify the feasibility.The results show that under the condition of grounding grid buried depth of 0.5 m and input frequency of 1~15MHz,and there is an inverse relationship between equivalent capacitance and distortion frequency,the phase angle is positively correlated with the degree of corrosion of grounding grid,and the error of signal distortion frequency can be positioned at 5%.This paper provides some ideas for the application of magnetic coupling grounding grid detection technology.展开更多
The single photon scattering properties in a pair of waveguides coupled by a whispering-gallery resonator in- teracting with a semiconductor quantum dot are investigated theoretically. The two waveguides support four ...The single photon scattering properties in a pair of waveguides coupled by a whispering-gallery resonator in- teracting with a semiconductor quantum dot are investigated theoretically. The two waveguides support four possible ports for an incident single photon. The quantum dot is considered a V-type system. The incident direction-dependent single photon scattering properties are studied and equal-output probability from the four ports for a single photon incident is discussed. The influences of backscattering between the two modes of the whispering-gallery resonator for incident direction-dependent single photon scattering properties are also pre- sented.展开更多
Resonance cavity is a basic element in optics,which has wide applications in optical devices.Coupled cavities(CCs)designed in metal-insulator-metal(MIM)bus waveguide are investigated through the finite difference time...Resonance cavity is a basic element in optics,which has wide applications in optical devices.Coupled cavities(CCs)designed in metal-insulator-metal(MIM)bus waveguide are investigated through the finite difference time domain method and coupled-mode theory.In the CCs,the resonant modes of the surface plasmon polaritons(SPPs)split with the thickness decreasing of the middle baffle.Through the coupled-mode theory analysis,it is found that the phase differences introduced in opposite and positive couplings between two cavities lead to mode splitting.The resonant wavelength of positive coupling mode can be tuned in a large range(about 644 nm)through adjusting the coupling strength,which is quite different from the classical adjustment of the optical path in a single cavity.Based on the resonances of the CCs in the MIM waveguide,more compact devices can be designed to manipulate SPPs propagation.A device is designed to realize flexible multiple-wavelength SPPs routing.The coupling in CC structures can be applied to the design of easy-integrated laser cavities,filters,multiple-wavelength management devices in SPPs circuits,nanosensors,etc.展开更多
The optical properties and plasmon resonance coupling of double coaxial gold nanotube arrays are inves- tigated. The results show that the optical transmission is highly tunable by varying the thicknesses of the inner...The optical properties and plasmon resonance coupling of double coaxial gold nanotube arrays are inves- tigated. The results show that the optical transmission is highly tunable by varying the thicknesses of the inner and outer nanotubes, the separation between the inner and outer nanotubes, and the dielectric parameters inside, between, and outside the two nanotubes. The shorter-wavelength transmission bands are very sensitive to the modification of the wall thickness of the outer nanotube, the separation, and the dielectric parameters between the double nanotubes. The dipole and multipolar plasmon modes are excited in our model. However, for small separation and refractive index, the dipole normal mode has a leading function in the transmission properties. Compared with the dipolar modes, the contribution of higher-order modes becomes larger as the parameters increase.展开更多
The three-dimensional(3D) finite element(FE) simulation and analysis of Love wave sensors based on polyisobutylene(PIB) layers/SiO_(2)/ST-90°X quartz structure are presented in this paper, as well as the investig...The three-dimensional(3D) finite element(FE) simulation and analysis of Love wave sensors based on polyisobutylene(PIB) layers/SiO_(2)/ST-90°X quartz structure are presented in this paper, as well as the investigation of coupled resonance effect on the acoustic properties of the devices. The mass sensitivity of the basic Love wave device with SiO_(2)guiding layers is solved analytically. And the highest mass sensitivity of 128 m^(2)/kg is obtained as h_(s)/λ = 0.175. The sensitivity of the Love wave sensors for sensing volatile organic compounds(VOCs) is greatly improved due to the presence of coupled resonance induced by the PIB nanorods on the device surface. The frequency shifts of the sensor corresponding to CH_(2)Cl_(2),CHCl_(3), CCl_(4), C_(2)Cl_(4), CH_(3)Cl and C_(2)HCl_(3) with the concentration of 100 ppm are 1.431 kHz, 5.507 kHz, 13.437 kHz,85.948 kHz, 0.127 kHz and 17.879 kHz, respectively. The viscoelasticity influence of the sensitive material on the characteristics of SAW sensors is also studied. By taking account of the viscoelasticity of the PIB layers, the sensitivities of the SAW sensors with the PIB film and PIB nanorods decay in different degree. The gas sensing property of the Love wave sensor with PIB nanorods is superior to that of the PIB films. Meanwhile, the Love wave sensors with PIB sensitive layers show good selectivity to C_(2)Cl_(4), making it an ideal selection for gas sensing applications.展开更多
Induced transparency phenomena and strong dispersion can be produced in a coupled resonator induced transparency(CRIT) structure.In this paper,we investigate the influences of structure parameters,such as amplitude ...Induced transparency phenomena and strong dispersion can be produced in a coupled resonator induced transparency(CRIT) structure.In this paper,we investigate the influences of structure parameters,such as amplitude reflection coefficient and loss,on transmission spectrum and dispersion of CRIT structure,and further study the control of dispersion in the structure.The results show that in the CRIT structure,adjusting the loss of resonators is an effective method of controlling dispersion and producing simultaneous normal and abnormal dispersion.When we choose approximate amplitude reflection coefficients of the two couplers,the decrease of transmittance due to loss could be effectively made up.In the experiment,we achieve the control of dispersion and simultaneous strong normal and abnormal dispersion in the CRIT structure comprised of fiber.The results indicate the CRIT structure has potential applications in optical signal processing and optical communication.展开更多
We investigate properties of the ponderomotive squeezing in an optomechanical system with two coupled resonators,where the tunable two-mode squeezing spectrum can be observed from the output field.It is realized that ...We investigate properties of the ponderomotive squeezing in an optomechanical system with two coupled resonators,where the tunable two-mode squeezing spectrum can be observed from the output field.It is realized that the squeezing orientation can be controlled by the detuning between the left cavity and pump laser.Especially,both cavity decay and environment temperature play a positive role in generating better pondermotive squeezing light.Strong squeezing spectra with a wide squeezing frequency range can be obtained by appropriate choice of parameters present in our optomechanical system.展开更多
A high-sensitivity plasmonic refractive-index sensor based on the asymmetrical coupling of two metal-insulator- metal waveguides with a nanodisk resonator is proposed and simulated in the finite-difference time domain...A high-sensitivity plasmonic refractive-index sensor based on the asymmetrical coupling of two metal-insulator- metal waveguides with a nanodisk resonator is proposed and simulated in the finite-difference time domain. Both analytic and simulated results show that the resonance wavelengths of the sensor have an approximate linear relationship with the refractive index of the materials which are filled into the slit waveguides and the disk- shaped resonator. The working mechanism of this sensor is exactly due to the linear relationship, based on which tile refractive index of the materials unknown can be obtained from the detection of the resonance wavelength. The measurement sensitivity can reach as high as 6.45 × 10-7, which is nearly five times higher than the results reported in the recent literature [Opt. Commun. 300 (2013) 265]. With an optimum design, the sensing value can be further improved, and it can be widely applied into the biological sensing. Tile sensor working for temperature sensing is also analyzed.展开更多
A high-overtone bulk acoustic resonator (HBAR) is composed of a substrate, a piezoelectric film and upper and lower electrodes, the influences of their structure parameter (thickness) and performance parameter (c...A high-overtone bulk acoustic resonator (HBAR) is composed of a substrate, a piezoelectric film and upper and lower electrodes, the influences of their structure parameter (thickness) and performance parameter (characteristic impedance) on effective electromechani- cal coupling coefficient K^2eff are investigated systematically. The relationship between K^2eff and these parameters is obtained by a lumped parameter equivalent circuit instead of distributed parameter equivalent circuit near the resonant frequency, and K^2eff at the resonance frequency closest to the given frequency is analyzed. The results show that K^2eff declines rapidly and oscillatorily with the continuous increase of the substrate thickness when the piezoelectric film thickness is fixed, and decreases inversely proportion to the thickness when the substrate thick-ness is greater than a certain value. With the ratio of the characteristic impedance of the substrate to the piezoelectric layer increasing, the maximum of K^2eff obtained from the vari- ation curve of K^2eff with the continuous increase of the piezoelectric film thickness decreases rapidly before reaching the minimum value, and later increases slowly. Fused silica with low impedance is appropriate as the substrate of HBAR to get a larger K^2eff. Compared with Al electrode, Au electrode can obtain larger K^2eff when the appropriate electrode thickness is selected. The revealed laws above mentioned provide the theoretical basis for optimizing parameters of HBAR.展开更多
基金supported by National Natural Science Foundation of China(No.51237003 and No.51577056)the Hunan Provincial Innovation Foundation for Postgraduate(No.CX2015B084)+1 种基金the Fundamental Research Funds for the Central Universities(No.2015-001)the Scientific Program of State Grid Corporation of China(No.521820140018)
文摘This paper firstly presents an equivalent coupling circuit modeling of multi-parallel inverters in microgrid operating in grid-connected mode. By using the model, the coupling resonance phenomena are explicitly investigated through the mathematical approach, and the intrinsic and extrinsic resonances exist widely in microgrid.Considering the inverter own reference current, other inverters reference current, and grid harmonic voltage, the distributions of resonance peaks with the growth in the number of inverters are obtained. Then, an active damping control parameter design method is proposed to attenuate coupling resonance, and the most salient feature is that the optimal range of the damping parameter can be easily located through an initiatively graphic method. Finally,simulations and experiments verify the validity of the proposed modeling and method.
基金Project supported by the National Natural Science Foundation of China(No.10632040)
文摘A nonlinear model of a low pressure cylinder-generator rotor system is presented to study sub-synchronous resonance and combined resonance. Analytical results are obtained by an averaging method. Transition sets and bifurcation diagrams are obtained based on the singularity theory for the two-state variable system. The bifurcation characteristics are analyzed to provide a basis for the optimal design and fault diagnosis of the rotor system. Finally, the theoretical results are verified with the numerical results.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.52002318 and 22103061)。
文摘Potential energy surfaces(PESs), vibrational frequencies, and infrared spectra are calculated for NF_(3)^(+) using ab initio calculations, based on UCCSD(T)/cc-p VTZ combined with vibrational configuration interaction(VCI). Based on an iterative algorithm, the surfaces(SURF) program adds automatic points to the lattice representation of the potential function, the one-dimensional and two-dimensional PESs are calculated after reaching a convergence threshold, finally the smooth image of the potential energy surface is fitted. The PESs accurately account for the interaction between the different modes, with the mode q_(6) symmetrical stretching vibrations having the greatest effect on the potential energy change of the whole system throughout the potential energy surface shift. The anharmonic frequencies are obtained when the VCI matrix is diagonalized. Fundamental frequencies, overtones, and combination bands of NF_(3)^(+) are calculated, which generate the degenerate phenomenon between their frequencies. Finally, the calculated anharmonic frequency is used to plot the infrared spectra.Modal antisymmetric stretching ν_(5) and symmetric stretching ν_(6) exhibit a phenomenon of large-intensity borrowing. This study can provide data to support the characterization in the laboratory.
基金Project supported,in part,by the National Natural Science Foundation of China(Grant No.41104065)the"Chen Guang"Program of Shanghai Municipal Ed-ucation Commission and Shanghai Education Development Foundation,China(Grant No.12CG047)+1 种基金the Scientific Research Innovation Program of Shanghai Municipal Education Commission,China(Grant No.13YZ022)the State Key Laboratory of Precision Measuring Technology and Instruments,China
文摘The method of numerical analysis is employed to study the resonance mechanism of the lumped parameter system model for acoustic mine detection. Based on the basic principle of the acoustic resonance technique for mine detection and the characteristics of low-frequency acoustics, the “soil-mine” system could be equivalent to a damping “mass-spring” resonance model with a lumped parameter analysis method. The dynamic simulation software, Adams, is adopted to analyze the lumped parameter system model numerically. The simulated resonance frequency and anti-resonance frequency are 151 Hz and 512 Hz respectively, basically in agreement with the published resonance frequency of 155 Hz and anti-resonance frequency of 513 Hz, which were measured in the experiment. Therefore, the technique of numerical simulation is validated to have the potential for analyzing the acoustic mine detection model quantitatively. The influences of the soil and mine parameters on the resonance characteristics of the soil–mine system could be investigated by changing the parameter setup in a flexible manner.
基金Supported by the National Natural Science Foundation of China (Grant Nos.11934004,11974230,and 11904192)the Education of Russian Federation (Grant No.FSRZ-2020-0008)。
文摘It has been reported that electron-rotation coupling plays a significant role in diatomic nuclear dynamics induced by intense VUV pulses [Phys. Rev. A 102(2020) 033114;Phys. Rev. Res. 2(2020) 043348]. As a further step, we present here investigations of the electron-rotation coupling effect in the presence of Auger decay channel for core-excited molecules, based on theoretical modeling of the total electron yield(TEY), resonant Auger scattering(RAS) and x-ray absorption spectra(XAS) for two showcases of CO and CH^(+) molecules excited by resonant intense x-ray pulses. The Wigner D-functions and the universal transition dipole operators are introduced to include the electron-rotation coupling for the core-excitation process. It is shown that with the pulse intensity up to 10^(16) W/cm^(2), no sufficient influence of the electron-rotation coupling on the TEY and RAS spectra can be observed. This can be explained by a suppression of the induced electron-rotation dynamics due to the fast Auger decay channel, which does not allow for effective Rabi cycling even at extreme field intensities,contrary to transitions in optical or VUV range. For the case of XAS, however, relative errors of about 10% and 30% are observed for the case of CO and CH^(+), respectively, when the electron-rotation coupling is neglected.It is concluded that conventional treatment of the photoexcitation, neglecting the electron-rotation coupling,can be safely and efficiently employed to study dynamics at the x-ray transitions by means of electron emission spectroscopy, yet the approximation breaks down for nonlinear processes as stimulated emission, especially for systems with light atoms.
文摘We propose an effective mechanism to couple superconducting charge and flux qubits by using a quantized nanomechanical resonator. The coupling between the charge and flux qubits can be controlled by the external flux of the charge qubit. Under the strong coupling limR, an iSWAP gate can be generated by this scheme. The experimental feasibility in our scheme is also presented.
基金the financial support from NSFC Chima(grants 61275188,81171375 and 61361160416)the key prjet of Guangdong province(2012A080203008)+1 种基金the Basic Research Pro-gram of Shenzhen City(jC20110520121A)State Key Laboratory Open Foundation Issue,China(grant 12K05ESPCT).
文摘We developed a biosensor that is capable for simultaneous surface plasmon resonance(SPR)sensing and hyperspectral fuores cence analysis in this paper.A symmetrical metal-dielectric slabscheme is employed for the excitation of coupled plasnon waveguide resonance(CPWR)in thepresent work.Resonance bet ween surface plasmon mode and the guided waveguide mode gen-erates narrower full width half-maximum of the refective curves which leads to increased pre.cision for the determination of refractive index over conventional SPR sensors.In addition,CPWR also fers longer surface propagation depths and higher surface electric field strengthsthat enable the excitation of fluorescence with hyperspectral technique to maintain an appreci-able signal-to-noise ratio.The refractive index information obtained from SPR sensing and thechemical properties obt ained through hyperspectral fluorescence analysis confirm each other toexclude false-positive or false-negative cases.The sensor provides a comprehensive understandingof the biological events on the sensor chips.
基金Supported by the National Natural Science Foundation of China under Grant No 61571365
文摘We discuss the dynamical behavior of a chemical network arising from the coupling of two Brusselators established by the relationship between products and substrates. Our interest is to investigate the coherence resonance (CR) phenomena caused by noise for a coupled Brusselator model in the vicinity of the Hopf bifurcation, which can be determined by the signM-to-noise ratio (SNR). The CR in two coupled Brusselators will be considered in the presence of the Gaussian colored noise and two uncorrelated Gaussian white noises. Simulation results show that, for the case of single noise, the SNR characterizing the degree of temporal regularity of coupled model reaches a maximum value at some optimal noise levels, and the noise intensity can enhance the CR phenomena of both subsystems with a similar trend but in different resonance degrees. Meanwhile, effects of noise intensities on CR of the second subsystem are opposite for the systems under we find that CR might be a general phenomenon in coupled two uncorrelated Gaussian white noises. Moreover, systems.
基金Project supported by the National Natural Science Foundation of China(Grant No.11674187)
文摘In this study, we observe a strong inverse magnetoelectric coupling in Fe52.5Co22.5B25.0/PZN-PT multiferroic heterostructure, which produces large electric field(E-field) tunability of microwave magnetic properties. With the increase of the E-field from 0 to 8 kV/cm, the magnetic anisotropy field Heffis dramatically enhanced from 169 to 600 Oe, which further leads to a significant enhancement of ferromagnetic resonance frequency from 4.57 to 8.73 GHz under zero bias magnetic field, and a simultaneous decrease of the damping constant α from 0.021 to 0.0186. These features demonstrate that this multiferroic composite is a promising candidate for fabricating E-field tunable microwave components.
基金Supported by the National Basic Research Program of China under Grant No 2011CB925600the National Natural Science Foundation of China under Grant Nos 11427807,91321311,10990100,11174057 and 61106092the Shanghai Science and Technology Committee under Grant No 14JC1406600
文摘Excited states of lnAs quantum dots (QDs) can be energetically coupled with the confined level of OaAs quantum wells (QWs) in a thin-barrier resonant tunneling diode (RTD). Single charge variation in the coupled QD can effectively switch on/off the resonant tunneling current passing through RTD, not only for emcient single-photon detection but also for photon-number-resolving detection. We present the study of the Q,D-QW coupling effect in the quantum dot coupled resonant tunneling diode (QD-cRTD) and figure out important factors for further improving the detector performance.
基金supported by the National Natural Science Foundation of China(Grant Nos.61275153 and 61320106014)the Natural Science Foundation of Zhejiang Province,China(Grant No.LY12A04002)+1 种基金the Natural Science Foundation of Ningbo City,China(Grant Nos.2010D10018 and 2012A610107)the K.C.Wong Magna Foundation of Ningbo University,China
文摘According to the plasmon hybridization theory, the plasmon resonance characteristics of the gold nanocrescent/nanoring(NCNR) structure are systematically investigated by the finite element method. It is found that the extinction spectra of NCNR structure exhibit multiple plasmon resonance peaks, which could be attributed to the result of the plasmon couplings between the multipolar plasmon modes of nanocrescent and the dipolar, quadrupolar, hexapolar, octupolar,decapolar plasmon modes of nanoring. By changing the geometric parameters, the intense and separate multiple plasmon resonance peaks are obtained and can be tuned in a wide wavelength range. It is further found that the plasmon coupling induces giant multipole electric field enhancements around the tips of the nanocrescent. The tunable and intense multiple plasmon resonances of NCNR structure may provide effective applications in multiplex biological sensing.
基金supported by the Science and Technology Research Innovation Team Project LT2019007 of the Department of Education of Liaoning Provincethe Discipline Innovation Team Project LNTU20TD-02,29 of Liaoning Technical University。
文摘Magnetically coupled resonant technology is a novel method for solving the breakpoint locating of power grounding grid.But the method can only detect breakpoints of a single mesh grounding grid at present.In this paper,a magnetically coupled resonant detection method for four-hole grounding grid breakpoint is proposed.Firstly,the equivalent circuit model of the four mesh grounding grid with two types of breakpoints,namely edge branch and intermediate branch,is established.The input impedance and phase angle of the system are obtained by analyzing the equivalent capacitance and equivalent resistance in the model.Secondly,the magnetically coupled resonant physical process of grounding grid faults is solved via HFSS software.The magnetic field intensity and phase frequency characteristic curves of four mesh holes with different branches and positions of breakpoints and different corrosion degrees are studied,and an experimental system is built to verify the feasibility.The results show that under the condition of grounding grid buried depth of 0.5 m and input frequency of 1~15MHz,and there is an inverse relationship between equivalent capacitance and distortion frequency,the phase angle is positively correlated with the degree of corrosion of grounding grid,and the error of signal distortion frequency can be positioned at 5%.This paper provides some ideas for the application of magnetic coupling grounding grid detection technology.
基金Supported by the National Natural Science Foundation of China under Grant No 11105001the Anhui Provincial Natural Science Foundation under Grant Nos 1408085QA22 and 1608085MA09
文摘The single photon scattering properties in a pair of waveguides coupled by a whispering-gallery resonator in- teracting with a semiconductor quantum dot are investigated theoretically. The two waveguides support four possible ports for an incident single photon. The quantum dot is considered a V-type system. The incident direction-dependent single photon scattering properties are studied and equal-output probability from the four ports for a single photon incident is discussed. The influences of backscattering between the two modes of the whispering-gallery resonator for incident direction-dependent single photon scattering properties are also pre- sented.
基金the National Natural Science Foundation of China(Grant No.11764006).
文摘Resonance cavity is a basic element in optics,which has wide applications in optical devices.Coupled cavities(CCs)designed in metal-insulator-metal(MIM)bus waveguide are investigated through the finite difference time domain method and coupled-mode theory.In the CCs,the resonant modes of the surface plasmon polaritons(SPPs)split with the thickness decreasing of the middle baffle.Through the coupled-mode theory analysis,it is found that the phase differences introduced in opposite and positive couplings between two cavities lead to mode splitting.The resonant wavelength of positive coupling mode can be tuned in a large range(about 644 nm)through adjusting the coupling strength,which is quite different from the classical adjustment of the optical path in a single cavity.Based on the resonances of the CCs in the MIM waveguide,more compact devices can be designed to manipulate SPPs propagation.A device is designed to realize flexible multiple-wavelength SPPs routing.The coupling in CC structures can be applied to the design of easy-integrated laser cavities,filters,multiple-wavelength management devices in SPPs circuits,nanosensors,etc.
基金supported by the Research Fund for the Doctoral Program of Higher Education of China(No.20100162110068)the Scientific Research Fund of Hunan Provincial Education Department(No.10B022)
文摘The optical properties and plasmon resonance coupling of double coaxial gold nanotube arrays are inves- tigated. The results show that the optical transmission is highly tunable by varying the thicknesses of the inner and outer nanotubes, the separation between the inner and outer nanotubes, and the dielectric parameters inside, between, and outside the two nanotubes. The shorter-wavelength transmission bands are very sensitive to the modification of the wall thickness of the outer nanotube, the separation, and the dielectric parameters between the double nanotubes. The dipole and multipolar plasmon modes are excited in our model. However, for small separation and refractive index, the dipole normal mode has a leading function in the transmission properties. Compared with the dipolar modes, the contribution of higher-order modes becomes larger as the parameters increase.
基金Project supported by the Foundation of Nanjing University of Posts and Telecommunications, China (Grant No. NY213018)。
文摘The three-dimensional(3D) finite element(FE) simulation and analysis of Love wave sensors based on polyisobutylene(PIB) layers/SiO_(2)/ST-90°X quartz structure are presented in this paper, as well as the investigation of coupled resonance effect on the acoustic properties of the devices. The mass sensitivity of the basic Love wave device with SiO_(2)guiding layers is solved analytically. And the highest mass sensitivity of 128 m^(2)/kg is obtained as h_(s)/λ = 0.175. The sensitivity of the Love wave sensors for sensing volatile organic compounds(VOCs) is greatly improved due to the presence of coupled resonance induced by the PIB nanorods on the device surface. The frequency shifts of the sensor corresponding to CH_(2)Cl_(2),CHCl_(3), CCl_(4), C_(2)Cl_(4), CH_(3)Cl and C_(2)HCl_(3) with the concentration of 100 ppm are 1.431 kHz, 5.507 kHz, 13.437 kHz,85.948 kHz, 0.127 kHz and 17.879 kHz, respectively. The viscoelasticity influence of the sensitive material on the characteristics of SAW sensors is also studied. By taking account of the viscoelasticity of the PIB layers, the sensitivities of the SAW sensors with the PIB film and PIB nanorods decay in different degree. The gas sensing property of the Love wave sensor with PIB nanorods is superior to that of the PIB films. Meanwhile, the Love wave sensors with PIB sensitive layers show good selectivity to C_(2)Cl_(4), making it an ideal selection for gas sensing applications.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61307076 and 61275066)the National Key Technology Research and Development Program of the Ministry of Science and Technology of China(Grant No.2012BAF14B11)the Postdoctoral Scientific Research Developmental Fund of Heilongjiang Province,China(Grant No.LBH-Q14042)
文摘Induced transparency phenomena and strong dispersion can be produced in a coupled resonator induced transparency(CRIT) structure.In this paper,we investigate the influences of structure parameters,such as amplitude reflection coefficient and loss,on transmission spectrum and dispersion of CRIT structure,and further study the control of dispersion in the structure.The results show that in the CRIT structure,adjusting the loss of resonators is an effective method of controlling dispersion and producing simultaneous normal and abnormal dispersion.When we choose approximate amplitude reflection coefficients of the two couplers,the decrease of transmittance due to loss could be effectively made up.In the experiment,we achieve the control of dispersion and simultaneous strong normal and abnormal dispersion in the CRIT structure comprised of fiber.The results indicate the CRIT structure has potential applications in optical signal processing and optical communication.
基金Project supported by the Doctoral Program of Guangdong Natural Science Foundation,China(Grant No.2018A030310109)the Doctoral Project of Guangdong Medical University(Grant No.B2017019)the Project of Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education of China(Grant No.QSQC1808)。
文摘We investigate properties of the ponderomotive squeezing in an optomechanical system with two coupled resonators,where the tunable two-mode squeezing spectrum can be observed from the output field.It is realized that the squeezing orientation can be controlled by the detuning between the left cavity and pump laser.Especially,both cavity decay and environment temperature play a positive role in generating better pondermotive squeezing light.Strong squeezing spectra with a wide squeezing frequency range can be obtained by appropriate choice of parameters present in our optomechanical system.
基金Supported by the National Natural Science Foundation of China under Grant No 61275059
文摘A high-sensitivity plasmonic refractive-index sensor based on the asymmetrical coupling of two metal-insulator- metal waveguides with a nanodisk resonator is proposed and simulated in the finite-difference time domain. Both analytic and simulated results show that the resonance wavelengths of the sensor have an approximate linear relationship with the refractive index of the materials which are filled into the slit waveguides and the disk- shaped resonator. The working mechanism of this sensor is exactly due to the linear relationship, based on which tile refractive index of the materials unknown can be obtained from the detection of the resonance wavelength. The measurement sensitivity can reach as high as 6.45 × 10-7, which is nearly five times higher than the results reported in the recent literature [Opt. Commun. 300 (2013) 265]. With an optimum design, the sensing value can be further improved, and it can be widely applied into the biological sensing. Tile sensor working for temperature sensing is also analyzed.
基金supported by the National Natural Science Foundation of China(11374327)
文摘A high-overtone bulk acoustic resonator (HBAR) is composed of a substrate, a piezoelectric film and upper and lower electrodes, the influences of their structure parameter (thickness) and performance parameter (characteristic impedance) on effective electromechani- cal coupling coefficient K^2eff are investigated systematically. The relationship between K^2eff and these parameters is obtained by a lumped parameter equivalent circuit instead of distributed parameter equivalent circuit near the resonant frequency, and K^2eff at the resonance frequency closest to the given frequency is analyzed. The results show that K^2eff declines rapidly and oscillatorily with the continuous increase of the substrate thickness when the piezoelectric film thickness is fixed, and decreases inversely proportion to the thickness when the substrate thick-ness is greater than a certain value. With the ratio of the characteristic impedance of the substrate to the piezoelectric layer increasing, the maximum of K^2eff obtained from the vari- ation curve of K^2eff with the continuous increase of the piezoelectric film thickness decreases rapidly before reaching the minimum value, and later increases slowly. Fused silica with low impedance is appropriate as the substrate of HBAR to get a larger K^2eff. Compared with Al electrode, Au electrode can obtain larger K^2eff when the appropriate electrode thickness is selected. The revealed laws above mentioned provide the theoretical basis for optimizing parameters of HBAR.