With the full-vector plane-wave method (FVPWM) and the full-vector beam propagation method (FVBPM), the dependences of the band-gap and mode characteristics on material index and cladding structure parameter in an...With the full-vector plane-wave method (FVPWM) and the full-vector beam propagation method (FVBPM), the dependences of the band-gap and mode characteristics on material index and cladding structure parameter in anti- resonance guiding photonic crystal fibres (ARGPCFs) are sufficiently analysed. An ARGPCF operating in the near- infrared wavelength is shown. The influences of the high index cylinders, glass interstitial apexes and silica structure on the characteristics of band-gaps and modes are deeply investigated. The equivalent planar waveguide theory is used for analysing such an ARGPCF filled by the isotropic materials, and the resonance and the anti-resonance characteristics r:~n h~ w~|] r^r~dlrtpd展开更多
This paper presents a phenomenon of“Pseudo-resonance”of beams androds discovered from experiments and computations,and gives the definition of“Pseudo-resonance”.The relationship of distribution between the frequen...This paper presents a phenomenon of“Pseudo-resonance”of beams androds discovered from experiments and computations,and gives the definition of“Pseudo-resonance”.The relationship of distribution between the frequency of pseu-do-resonance and that of anti-resonance is found,and an analytic solution for thetransfer function between any two points on a beam or rod is established.The law ofdistribution of the anti-resonant frequencies,as well as the relation between the fre-quency distribution and the nodes of vibration is also proposed.展开更多
A parallel-coupled double quantum dot (PCDQD) system with two multi-quantum dot chains is designed. Conductance versus Fermi energy level is investigated utilizing the non-equilibrium Green's function approach. If ...A parallel-coupled double quantum dot (PCDQD) system with two multi-quantum dot chains is designed. Conductance versus Fermi energy level is investigated utilizing the non-equilibrium Green's function approach. If two quantum dots are added on each side of the PCDQD system, additional Breit Wigner and Fano resonances occur in the conductance spectra. If quantum dots are added on one side of the system, small Fano resonances can be observed in the conductance spectra. Adjusting the number of side-coupled quantum dots, the anti-resonance bands emerge at different positions, which makes the system applicable as a quantum switching device. Moreover, the I-V characteristic curve presents the step characteristic and the width of the step decreases with increasing the number of side-coupled quantum dots.展开更多
An alternative technique for crack detection in a Timoshenko beam based on the first anti-resonant frequency is presented in this paper. Unlike the natural frequency, the anti-resonant frequency is a local parameter r...An alternative technique for crack detection in a Timoshenko beam based on the first anti-resonant frequency is presented in this paper. Unlike the natural frequency, the anti-resonant frequency is a local parameter rather than a global parameter of structures, thus the proposed technique can be used to locate the structural defects. An impedance analysis of a cracked beam stimulated by a harmonic force based on the Timoshenko beam formulation is investigated. In order to characterize the local discontinuity due to cracks, a rotational spring model based on fracture mechanics is proposed to model the crack. Subsequently, the proposed method is verified by a numerical example of a simply-supported beam with a crack. The effect of the crack size on the anti-resonant frequency is investigated. The position of the crack of the simply-supported beam is also determined by the anti-resonance technique. The proposed technique is further applied to the "contaminated" anti-resonant frequency to detect crack damage, which is obtained by adding 1-3% noise to the calculated data. It is found that the proposed technique is effective and free from the environment noise. Finally, an experimental study is performed, which further verifies the validity of the proposed crack identification technique.展开更多
In the semiconductor manufacturing industry,the dynamic model of a controlled object is usually obtained from a frequency sweeping method before motion control.However,the existing isolators cannot properly isolate th...In the semiconductor manufacturing industry,the dynamic model of a controlled object is usually obtained from a frequency sweeping method before motion control.However,the existing isolators cannot properly isolate the disturbance of the inertial force on the platform base during frequency sweeping(the frequency is between 0 Hz and the natural frequency).In this paper,an adjustable anti-resonance frequency controller for a dual-stage actuation semi-active vibration isolation system(DSASAVIS)is proposed.This system has a significant anti-resonance characteristic;that is,the vibration amplitude can drop to nearly zero at a particular frequency,which is called the anti-resonance frequency.The proposed controller is designed to add an adjustable anti-resonance frequency to fully use this unique anti-resonance characteristic.Experimental results show that the closed-loop transmissibility is less than−15 dB from 0 Hz to the initial anti-resonance frequency.Furthermore,it is less than−30 dB around an added anti-resonance frequency which can be adjusted from 0 Hz to the initial anti-resonance frequency by changing the parameters of the proposed controller.With the proposed controller,the disturbance amplitude of the payload decays from 4 to 0.5 mm/s with a reduction of 87.5%for the impulse disturbance applied to the platform base.Simultaneously,the system can adjust the anti-resonance frequency point in real time by tracking the frequency sweeping disturbances,and a good vibration isolation performance is achieved.This indicates that the DSA-SAVIS and the proposed controller can be applied in the guarantee of an ultra-low vibration environment,especially at frequency sweeping in the semiconductor manufacturing industry.展开更多
The coupling efficiency of hollow-core fiber changes with temperature,which leads to the decrease of the finesse(F)of fiber resonator and limits the performance of the resonant fiber optic gyroscope(R-FOG)system.Negat...The coupling efficiency of hollow-core fiber changes with temperature,which leads to the decrease of the finesse(F)of fiber resonator and limits the performance of the resonant fiber optic gyroscope(R-FOG)system.Negative-curvature antiresonant fiber(ARF)can maintain single-mode characteristics under the condition of large mode field diameter,achieve efficient and stable fiber coupling,and significantly improve the consistency of the F of the spatial coupling resonator in variable temperature environment.A new type of ARF with a mode field diameter(MFD)of 25μm is used to fabricate a fiber resonator with a length of 5.14 m.In the range of 25℃-75℃,the average F is 31.45.The ARF resonator is used to construct an R-FOG system that shows long-term bias stability(3600 s)of3.1°/h at room temperature,4.6°/h at 75℃.To our knowledge,this is the best reported index of hollow-core fiber resonator and R-FOG system within the temperature variation range of 50℃ test.展开更多
By exact resolution of coupled ideal chains connecting an extra side site,we show that the so-called'anti-resonant effect' is suppressed when the electron energy is inside the overlap region of extended bands ...By exact resolution of coupled ideal chains connecting an extra side site,we show that the so-called'anti-resonant effect' is suppressed when the electron energy is inside the overlap region of extended bands of the idealtight-binding chains.When the electronic energy is outside the band overlap region,the existence of 'anti-resonanteffect' is tuned by details of local connectivity around the extra side site and can be suppressed by introduction ofmagnetic flux.展开更多
The principles of electromagnetic induction are applied in many devices and systems, including induction cookers, transformers and wireless energy transfer;however, few data are available on resonance in the electromo...The principles of electromagnetic induction are applied in many devices and systems, including induction cookers, transformers and wireless energy transfer;however, few data are available on resonance in the electromotive force (EMF) of electromagnetic induction. We studied electromagnetic induction between two circular coils of wire: one is the source coil and the other is the pickup (or induction) coil. The measured EMF versus frequency graphs reveals the existence of a resonance/anti-resonance in the EMF of electromagnetic induction through free space. We found that it is possible to control the system’s resonance and anti-resonance frequencies. In some devices, a desired resonance or antiresonance frequency is achieved by varying the size of the resonator. Here, by contrast, our experimental results show that the system’s resonance and anti-resonance frequencies can be adjusted by varying the distance between the two coils or the number of turns of the induction coil.展开更多
Intracavity tunneling induced transparency in asymmetric double-quantum wells embedded in a microcavity in the ultrastrong-coupling regime is investigated by the input-output theory developed by Ciuti and Carusotto. I...Intracavity tunneling induced transparency in asymmetric double-quantum wells embedded in a microcavity in the ultrastrong-coupling regime is investigated by the input-output theory developed by Ciuti and Carusotto. In this system a narrow spectra can be realized under anti-resonant terms of the external dissipation. Fano-interference asymmetric line profile is found in the absorption spectra.展开更多
Impedance eduction methods have been developed for decades to meet the increasing need for high-quality impedance data in the design and optimization of acoustic liners.To this end,it is important to fully investigate...Impedance eduction methods have been developed for decades to meet the increasing need for high-quality impedance data in the design and optimization of acoustic liners.To this end,it is important to fully investigate the uncertainty problem,to which only limited attention has been devoted so far.This paper considers the possibility of acoustically-induced structural vibration as a nonnegligible uncertainty or error source in impedance eduction experiments.As the frequency moves away from the resonant frequency,with the increase in the value of cavity reactance,the acoustic particle velocity inside liner orifices possibly decreases to the extent comparable to the vibration velocity of liner facing sheet.Thus,the acoustically-induced vibration,although generally being weak except at the inherent structural frequencies,may considerably affect the impedance eduction results near the anti-resonant frequency where the liner has poor absorption.To demonstrate the effect of structural vibration,the vibration velocity of liner facing sheet is estimated from the experimentally educed admittance of the liner samples whose orifices are sealed with tape.Further,a three-dimensional numerical model is set up,in which normal particle velocity is introduced over the solid portion of liner facing sheet to imitate structural vibration,rather than directly solving the acoustic-structural coupling problem.As shown by the results,the vibration of liner facing sheet,whose velocity is as small as estimated by the experiment,can result in anomalous deviation of the educed impedance from the impedance model near the anti-resonant frequency.The trend that the anomalous deviation varies with frequency is numerically captured.展开更多
Continuous operation of fiber gas Raman lasing at the 1135 nm wavelength is experimentally demonstrated with an output power exceeding 26 W.Rotational stimulated Raman scattering(Rot-SRS)is generated in the hydrogen g...Continuous operation of fiber gas Raman lasing at the 1135 nm wavelength is experimentally demonstrated with an output power exceeding 26 W.Rotational stimulated Raman scattering(Rot-SRS)is generated in the hydrogen gas filled 50 m homemade anti-resonant hollow-core fiber(AR-HCF).A single-frequency fiber laser at the 1064 nm wavelength is used as the pump source,and a minimum threshold of 31.5 W is measured where the core diameter of AR-HCF reaches37μm.Up to 40.4%power conversion efficiency of forward Rot-SRS is achieved in the single-pass configuration,corresponding to a quantum efficiency of 43.1%.Over 1 W strong backward Rot-SRS is observed in the experiment,ultimately limiting the further increase of Rot-SRS generation in the forward direction.展开更多
In this paper,a novel all-solid anti-resonant single crystal fiber(AR-SCF)with high refractive index tubes cladding is proposed.By producing the cladding tubes with high refractive index material,the AR guiding mechan...In this paper,a novel all-solid anti-resonant single crystal fiber(AR-SCF)with high refractive index tubes cladding is proposed.By producing the cladding tubes with high refractive index material,the AR guiding mechanism can be realized for the SCF,which can reduce the mode number to achieve single-mode or few-mode transmission.The influences of dif-ferent materials and structures on the confinement loss and effective guided mode number for wavelengths of 2-3μm are investigated.Then,the optimal AR-SCF structures for different wavelengths are determined.Furthermore,the influences of different fabrication errors are analyzed.This work would provide insight to new opportunities in the novel design of SCFs by AR,which would greatly impact the fields of laser application,supercontinum generation,and SCF sensors.展开更多
The mode localization phenomenon of disordered weakly coupled resonators(WCRs)is being used as a novel transduction scheme to further enhance the sensitivity of micromechanical resonant sensors.In this paper,two novel...The mode localization phenomenon of disordered weakly coupled resonators(WCRs)is being used as a novel transduction scheme to further enhance the sensitivity of micromechanical resonant sensors.In this paper,two novel characteristics of mode localization are described.First,we found that the anti-resonance loci behave as a linear function of the stiffness perturbation.The antiresonance behavior can be regarded as a new manifestation of mode localization in the frequency domain,and mode localization occurs at a deeper level as the anti-resonance approaches closer to the resonance.The anti-resonance loci can be used to identify the symmetry of the WCRs and the locations of the perturbation.Second,by comparing the forced localization responses of the WCRs under both the single-resonator-driven(SRD)scheme and the double-resonator-driven(DRD)scheme,we demonstrated that the DRD scheme extends the linear measurement scale while sacrificing a certain amount of sensitivity.We also demonstrated experimentally that the amplitude ratio-based sensitivity under the DRD scheme is approximately an order of magnitude lower than that under the SRD scheme,that is,the amplitude ratio-based sensitivity is−70.44%(Nm^(−1))^(−1) under the DRD scheme,while it is−785.6%(Nm^(−)1)^(−1) under the SRD scheme.These characteristics of mode localization are valuable for the design and control of WCR-based sensors.展开更多
基金partly supported by the National Key Basic Research Special Foundation of China (Grant Nos. 2010CB327605 and 2010CB328300)the National High-Technology Research and Development Program of China (Grant No. 2009AA01Z220)+3 种基金the Key Grant of the Chinese Ministry of Education (Grant No. 109015)the Discipline Co-construction Project of Beijing Municipal Commission of Education,China (Grant No. YB20081001301)the Open Fund of Key Laboratory of Information Photonics and Optical Communications (Beijing University of Posts and Telecommunications),Chinese Ministry of Educationthe Specialized Research Fund for the Doctoral Program of Beijing University of Posts and Telecommunications (Grant No. CX201023)
文摘With the full-vector plane-wave method (FVPWM) and the full-vector beam propagation method (FVBPM), the dependences of the band-gap and mode characteristics on material index and cladding structure parameter in anti- resonance guiding photonic crystal fibres (ARGPCFs) are sufficiently analysed. An ARGPCF operating in the near- infrared wavelength is shown. The influences of the high index cylinders, glass interstitial apexes and silica structure on the characteristics of band-gaps and modes are deeply investigated. The equivalent planar waveguide theory is used for analysing such an ARGPCF filled by the isotropic materials, and the resonance and the anti-resonance characteristics r:~n h~ w~|] r^r~dlrtpd
文摘This paper presents a phenomenon of“Pseudo-resonance”of beams androds discovered from experiments and computations,and gives the definition of“Pseudo-resonance”.The relationship of distribution between the frequency of pseu-do-resonance and that of anti-resonance is found,and an analytic solution for thetransfer function between any two points on a beam or rod is established.The law ofdistribution of the anti-resonant frequencies,as well as the relation between the fre-quency distribution and the nodes of vibration is also proposed.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11447132 and 11504042the Chongqing Science and Technology Commission Project under Grant Nos cstc2014jcyj A00032 and cstc2016jcyj A1158the Scientific Research Project for Advanced Talents of Yangtze Normal University under Grant No 2017KYQD09
文摘A parallel-coupled double quantum dot (PCDQD) system with two multi-quantum dot chains is designed. Conductance versus Fermi energy level is investigated utilizing the non-equilibrium Green's function approach. If two quantum dots are added on each side of the PCDQD system, additional Breit Wigner and Fano resonances occur in the conductance spectra. If quantum dots are added on one side of the system, small Fano resonances can be observed in the conductance spectra. Adjusting the number of side-coupled quantum dots, the anti-resonance bands emerge at different positions, which makes the system applicable as a quantum switching device. Moreover, the I-V characteristic curve presents the step characteristic and the width of the step decreases with increasing the number of side-coupled quantum dots.
基金Project supported by the National Natural Science Foundation of China(No.50608036)Program for New Century Excellent Talents in Universities.
文摘An alternative technique for crack detection in a Timoshenko beam based on the first anti-resonant frequency is presented in this paper. Unlike the natural frequency, the anti-resonant frequency is a local parameter rather than a global parameter of structures, thus the proposed technique can be used to locate the structural defects. An impedance analysis of a cracked beam stimulated by a harmonic force based on the Timoshenko beam formulation is investigated. In order to characterize the local discontinuity due to cracks, a rotational spring model based on fracture mechanics is proposed to model the crack. Subsequently, the proposed method is verified by a numerical example of a simply-supported beam with a crack. The effect of the crack size on the anti-resonant frequency is investigated. The position of the crack of the simply-supported beam is also determined by the anti-resonance technique. The proposed technique is further applied to the "contaminated" anti-resonant frequency to detect crack damage, which is obtained by adding 1-3% noise to the calculated data. It is found that the proposed technique is effective and free from the environment noise. Finally, an experimental study is performed, which further verifies the validity of the proposed crack identification technique.
基金Project supported by the National Natural Science Foundation of China(No.51975160)。
文摘In the semiconductor manufacturing industry,the dynamic model of a controlled object is usually obtained from a frequency sweeping method before motion control.However,the existing isolators cannot properly isolate the disturbance of the inertial force on the platform base during frequency sweeping(the frequency is between 0 Hz and the natural frequency).In this paper,an adjustable anti-resonance frequency controller for a dual-stage actuation semi-active vibration isolation system(DSASAVIS)is proposed.This system has a significant anti-resonance characteristic;that is,the vibration amplitude can drop to nearly zero at a particular frequency,which is called the anti-resonance frequency.The proposed controller is designed to add an adjustable anti-resonance frequency to fully use this unique anti-resonance characteristic.Experimental results show that the closed-loop transmissibility is less than−15 dB from 0 Hz to the initial anti-resonance frequency.Furthermore,it is less than−30 dB around an added anti-resonance frequency which can be adjusted from 0 Hz to the initial anti-resonance frequency by changing the parameters of the proposed controller.With the proposed controller,the disturbance amplitude of the payload decays from 4 to 0.5 mm/s with a reduction of 87.5%for the impulse disturbance applied to the platform base.Simultaneously,the system can adjust the anti-resonance frequency point in real time by tracking the frequency sweeping disturbances,and a good vibration isolation performance is achieved.This indicates that the DSA-SAVIS and the proposed controller can be applied in the guarantee of an ultra-low vibration environment,especially at frequency sweeping in the semiconductor manufacturing industry.
基金supported by the National Natural Science Foundation of China(61973019)。
文摘The coupling efficiency of hollow-core fiber changes with temperature,which leads to the decrease of the finesse(F)of fiber resonator and limits the performance of the resonant fiber optic gyroscope(R-FOG)system.Negative-curvature antiresonant fiber(ARF)can maintain single-mode characteristics under the condition of large mode field diameter,achieve efficient and stable fiber coupling,and significantly improve the consistency of the F of the spatial coupling resonator in variable temperature environment.A new type of ARF with a mode field diameter(MFD)of 25μm is used to fabricate a fiber resonator with a length of 5.14 m.In the range of 25℃-75℃,the average F is 31.45.The ARF resonator is used to construct an R-FOG system that shows long-term bias stability(3600 s)of3.1°/h at room temperature,4.6°/h at 75℃.To our knowledge,this is the best reported index of hollow-core fiber resonator and R-FOG system within the temperature variation range of 50℃ test.
基金Supported by the National Natural Science Foundation of China under Grant No.10604006Super Computer Center of Beijing Normal University
文摘By exact resolution of coupled ideal chains connecting an extra side site,we show that the so-called'anti-resonant effect' is suppressed when the electron energy is inside the overlap region of extended bands of the idealtight-binding chains.When the electronic energy is outside the band overlap region,the existence of 'anti-resonanteffect' is tuned by details of local connectivity around the extra side site and can be suppressed by introduction ofmagnetic flux.
文摘The principles of electromagnetic induction are applied in many devices and systems, including induction cookers, transformers and wireless energy transfer;however, few data are available on resonance in the electromotive force (EMF) of electromagnetic induction. We studied electromagnetic induction between two circular coils of wire: one is the source coil and the other is the pickup (or induction) coil. The measured EMF versus frequency graphs reveals the existence of a resonance/anti-resonance in the EMF of electromagnetic induction through free space. We found that it is possible to control the system’s resonance and anti-resonance frequencies. In some devices, a desired resonance or antiresonance frequency is achieved by varying the size of the resonator. Here, by contrast, our experimental results show that the system’s resonance and anti-resonance frequencies can be adjusted by varying the distance between the two coils or the number of turns of the induction coil.
文摘Intracavity tunneling induced transparency in asymmetric double-quantum wells embedded in a microcavity in the ultrastrong-coupling regime is investigated by the input-output theory developed by Ciuti and Carusotto. In this system a narrow spectra can be realized under anti-resonant terms of the external dissipation. Fano-interference asymmetric line profile is found in the absorption spectra.
基金funded by the National Science and Technology Major Project,China(No.2017-II-0008-0022)。
文摘Impedance eduction methods have been developed for decades to meet the increasing need for high-quality impedance data in the design and optimization of acoustic liners.To this end,it is important to fully investigate the uncertainty problem,to which only limited attention has been devoted so far.This paper considers the possibility of acoustically-induced structural vibration as a nonnegligible uncertainty or error source in impedance eduction experiments.As the frequency moves away from the resonant frequency,with the increase in the value of cavity reactance,the acoustic particle velocity inside liner orifices possibly decreases to the extent comparable to the vibration velocity of liner facing sheet.Thus,the acoustically-induced vibration,although generally being weak except at the inherent structural frequencies,may considerably affect the impedance eduction results near the anti-resonant frequency where the liner has poor absorption.To demonstrate the effect of structural vibration,the vibration velocity of liner facing sheet is estimated from the experimentally educed admittance of the liner samples whose orifices are sealed with tape.Further,a three-dimensional numerical model is set up,in which normal particle velocity is introduced over the solid portion of liner facing sheet to imitate structural vibration,rather than directly solving the acoustic-structural coupling problem.As shown by the results,the vibration of liner facing sheet,whose velocity is as small as estimated by the experiment,can result in anomalous deviation of the educed impedance from the impedance model near the anti-resonant frequency.The trend that the anomalous deviation varies with frequency is numerically captured.
基金partly supported by the International Science and Technology Cooperation Program(No.2018YFE0115600)National Natural Science Foundation of China(No.61935002)+2 种基金Chinese Academy of Sciences(No.ZDBSLY-JSC020)supported by the CAS Pioneer Hundred Talents ProgramNational Key R&D Program of China(Nos.2020YFB1312802 and 2020YFB1805900)。
文摘Continuous operation of fiber gas Raman lasing at the 1135 nm wavelength is experimentally demonstrated with an output power exceeding 26 W.Rotational stimulated Raman scattering(Rot-SRS)is generated in the hydrogen gas filled 50 m homemade anti-resonant hollow-core fiber(AR-HCF).A single-frequency fiber laser at the 1064 nm wavelength is used as the pump source,and a minimum threshold of 31.5 W is measured where the core diameter of AR-HCF reaches37μm.Up to 40.4%power conversion efficiency of forward Rot-SRS is achieved in the single-pass configuration,corresponding to a quantum efficiency of 43.1%.Over 1 W strong backward Rot-SRS is observed in the experiment,ultimately limiting the further increase of Rot-SRS generation in the forward direction.
基金This work was supported in part by the Fundamental Research Funds for the Central Universities(No.2019JBM345)in part by the Beijing Natural Science Foundation(No.4192047)in part by the National Natural Science Foundation of China(Grant No.61875064).
文摘In this paper,a novel all-solid anti-resonant single crystal fiber(AR-SCF)with high refractive index tubes cladding is proposed.By producing the cladding tubes with high refractive index material,the AR guiding mechanism can be realized for the SCF,which can reduce the mode number to achieve single-mode or few-mode transmission.The influences of dif-ferent materials and structures on the confinement loss and effective guided mode number for wavelengths of 2-3μm are investigated.Then,the optimal AR-SCF structures for different wavelengths are determined.Furthermore,the influences of different fabrication errors are analyzed.This work would provide insight to new opportunities in the novel design of SCFs by AR,which would greatly impact the fields of laser application,supercontinum generation,and SCF sensors.
基金This work was supported by the National Natural Science Foundation of China under Grant 51575454.
文摘The mode localization phenomenon of disordered weakly coupled resonators(WCRs)is being used as a novel transduction scheme to further enhance the sensitivity of micromechanical resonant sensors.In this paper,two novel characteristics of mode localization are described.First,we found that the anti-resonance loci behave as a linear function of the stiffness perturbation.The antiresonance behavior can be regarded as a new manifestation of mode localization in the frequency domain,and mode localization occurs at a deeper level as the anti-resonance approaches closer to the resonance.The anti-resonance loci can be used to identify the symmetry of the WCRs and the locations of the perturbation.Second,by comparing the forced localization responses of the WCRs under both the single-resonator-driven(SRD)scheme and the double-resonator-driven(DRD)scheme,we demonstrated that the DRD scheme extends the linear measurement scale while sacrificing a certain amount of sensitivity.We also demonstrated experimentally that the amplitude ratio-based sensitivity under the DRD scheme is approximately an order of magnitude lower than that under the SRD scheme,that is,the amplitude ratio-based sensitivity is−70.44%(Nm^(−1))^(−1) under the DRD scheme,while it is−785.6%(Nm^(−)1)^(−1) under the SRD scheme.These characteristics of mode localization are valuable for the design and control of WCR-based sensors.