We establish a slow manifold for a fast-slow dynamical system with anomalous diffusion,where both fast and slow components are influenced by white noise.Furthermore,we verify the exponential tracking property for the ...We establish a slow manifold for a fast-slow dynamical system with anomalous diffusion,where both fast and slow components are influenced by white noise.Furthermore,we verify the exponential tracking property for the established random slow manifold,which leads to a lower dimensional reduced system.Alongside this we consider a parameter estimation method for a nonlocal fast-slow stochastic dynamical system,where only the slow component is observable.In terms of quantifying parameters in stochastic evolutionary systems,the provided method offers the advantage of dimension reduction.展开更多
We theoretically explore the tunability of magnomechanically induced transparency(MMIT) phenomenon and fastslow light effect in a hybrid cavity magnomechanical system in which a high-quality yttrium iron garnet(YIG) s...We theoretically explore the tunability of magnomechanically induced transparency(MMIT) phenomenon and fastslow light effect in a hybrid cavity magnomechanical system in which a high-quality yttrium iron garnet(YIG) sphere and an atomic ensemble are placed inside a microwave cavity. In the probe output spectrum, we can observe magnoninduced transparency(MIT) and MMIT due to the photon-magnon and phonon-magnon couplings. We further investigate the effect of atomic ensemble on the absorption spectrum. The results show that better transparency can be obtained by choosing appropriate atomic ensemble parameters. We give an explicit explanation for the mechanism of the Fano resonance phenomenon. Moreover, we discuss phenomena of slow-light propagation. The maximum group delay increases significantly with the increasing atom–cavity coupling strength, and the conversion between slow light and fast light can also be achieved by adjusting the atom–cavity coupling strength. These results may have potential applications for quantum information processing and high precision measurements.展开更多
Internal effects of the dynamic behaviors and nonlinear characteristics of a coupled fractional order hydropower generation system(HGS) are analyzed. A mathematical model of hydro-turbine governing system(HTGS) with r...Internal effects of the dynamic behaviors and nonlinear characteristics of a coupled fractional order hydropower generation system(HGS) are analyzed. A mathematical model of hydro-turbine governing system(HTGS) with rigid water hammer and hydro-turbine generator unit(HTGU) with fractional order damping forces are proposed. Based on Lagrange equations, a coupled fractional order HGS is established. Considering the dynamic transfer coefficient eis variational during the operation, introduced e as a periodic excitation into the HGS. The internal relationship of the dynamic behaviors between HTGS and HTGU is analyzed under different parameter values and fractional order. The results show obvious fast–slow dynamic behaviors in the HGS, causing corresponding vibration of the system, and some remarkable evolution phenomena take place with the changing of the periodic excitation parameter values.展开更多
Flexible joints are usually used to transfer velocities in robot systems and may lead to delays in motion transformation due to joint flexibility. In this paper, a linkrotor structure connected by a flexible joint or ...Flexible joints are usually used to transfer velocities in robot systems and may lead to delays in motion transformation due to joint flexibility. In this paper, a linkrotor structure connected by a flexible joint or shaft is firstly modeled to be a slow-fast delayed system when moment of inertia of the lightweight link is far less than that of the heavy rotor. To analyze the stability and oscillations of the slowfast system, the geometric singular perturbation method is extended, with both slow and fast manifolds expressed analytically. The stability of the slow manifold is investigated and critical boundaries are obtained to divide the stable and the unstable regions. To study effects of the transformation delay on the stability and oscillations of the link, two quantitatively different driving forces derived from the negative feedback of the link are considered. The results show that one of these two typical driving forces may drive the link to exhibit a stable state and the other kind of driving force may induce a relaxation oscillation for a very small delay. However, the link loses stability and undergoes regular periodic and bursting oscillation when the transformation delay is large. Basically, a very small delay does not affect the stability of the slow manifold but a large delay affects substantially.展开更多
In some worldwide hard coal basins recovery of methane from virgin coal beds is difficult. In general,mentioned difficulties are related to geo-mechanical, petrographical and physical-chemical properties of coals in q...In some worldwide hard coal basins recovery of methane from virgin coal beds is difficult. In general,mentioned difficulties are related to geo-mechanical, petrographical and physical-chemical properties of coals in question, occurring for example in the Bowen Basin(Australia) or the Upper Silesian Coal Basin(Poland). Among numerous properties and parameters, the following are very essential: susceptibility of coal beds to deformation connected with coal stress state change and contemporary shrinkage of the coal matrix during methane desorption. Those adverse geo-mechanical and physical-chemical effects are accompanied by essential change of the porous coal structure, which under these disadvantageous conditions is very complex. This study aims to show difficulties, which occur in phase of recognition of the methane-reach coal deposit. Volume absorbed methane(not surface adsorbed) in sub-micropores having minimal size comparable with gas molecule diameter must possess energy allowing separation of the nodes and methane release to micropores.展开更多
We theoretically explore the tunability of optomechanically induced transparency(OMIT)phenomenon and fast-slow light effect in a loop-coupled hybrid optomechanical system in which two optical modes are coupled to a co...We theoretically explore the tunability of optomechanically induced transparency(OMIT)phenomenon and fast-slow light effect in a loop-coupled hybrid optomechanical system in which two optical modes are coupled to a common mechanical mode.In the probe output spectrum,we find that the interference phenomena OMIT caused by the optomechanical interactions and the normal mode splitting(NMS)induced by the strong tunnel coupling between the cavities can be observed.We further observe that the tunnel interaction will affect the distance and the heights of the sideband absorption peaks.The results also show that the switch from absorption to amplification can be realized by tuning the driving strength because of the existence of stability condition.Except from modulating the tunnel interaction,the conversion between slow light and fast light also can be achieved by adjusting the optomechanical interaction in the output field.This study may provide a potential application in the fields of high precision measurement and quantum information processing.展开更多
The urban slow traffic system refers to the traffic system in the city that can allow people to walk, ride, travel by bus and other slow travel. Through 4,728 papers on slow moving system in China from 2000 to 2020 in...The urban slow traffic system refers to the traffic system in the city that can allow people to walk, ride, travel by bus and other slow travel. Through 4,728 papers on slow moving system in China from 2000 to 2020 included in CNKI, analysis and summary of literature publishing trend, research strength,research focus and development trend are conducted based on CiteSpace software. It is expected to provide reference for future research in this field.展开更多
In this paper we will try to create, propose and analyze structure of a slow light device, based on plasmonic induced transparency in a metal-dielectric-metal based ring resonator. Group index by first design about 37...In this paper we will try to create, propose and analyze structure of a slow light device, based on plasmonic induced transparency in a metal-dielectric-metal based ring resonator. Group index by first design about 37 and second design about 35 earned. The proposed dielectric material is Poly Methyl Meta Acrylate (PMMA) sandwiched by gold metal cladding. Finite Element Method-con- ducted Electromagnetic simulations are employed to evaluate the plasmonic designs for behavior of slow light. The signal and pump wavelength are assumed to be 830 nm and 1550 nm respectively in the systems. The overall length of the plasmonic slow light system is 600 nm. In a wide range of frequency bands, the optical properties of metals can be described with a plasma model. The optical signal can be achieved with the use of surface waves on the boundary between the insulating materials and metals with dimensions smaller than the diffraction limit. The main goal, is estimation of optical characteristics such as bandwidth, the Real and Imaginary parts of refractive index, group velocity and slow down factor in such optical devices. The obtained results and observations, can be useful in basic research and the production of highly integrated plasmonic devices.展开更多
We theoretically investigate the magnomechanically induced transparency phenomenon,Fano resonance and the slow-fast light effect in the situation where an atomic ensemble is placed inside the hybrid cavity of an optom...We theoretically investigate the magnomechanically induced transparency phenomenon,Fano resonance and the slow-fast light effect in the situation where an atomic ensemble is placed inside the hybrid cavity of an optomagnomechanical system.The system is driven by dual optical and phononic drives.We show double magnomechanically induced transparency in the probe output spectrum by exploiting the phonon-photon coupling strength.Then,we study the effects of the decay rate of the cavity and the atomic ensemble on magnomechanically induced transparency.In addition,we demonstrate that effective detuning of the cavity field frequency changes the transparency window from a symmetrical to an asymmetrical profile,resembling Fano resonances.Further,the fast and slow light effects in the system are explored.We show that the slow light profile is enhanced by adjusting the phonon-photon coupling strength.This result may have potential applications in quantum information processing and communication.展开更多
A limit theorem which can simplify slow–fast dynamical systems driven by fractional Brownian motion with the Hurst parameter H inside the（1/2, 1） interval has been proved. The slow variables of the original system ...A limit theorem which can simplify slow–fast dynamical systems driven by fractional Brownian motion with the Hurst parameter H inside the（1/2, 1） interval has been proved. The slow variables of the original system can be approximated by the solution of the simplified equations in the sense of mean square. An example is presented to illustrate the applications of the limit theorem.展开更多
This paper deals with the quenching behavior of positive solutions to the Newton filtration equations coupled with boundary singularities.We determine quenching rates for non-simultaneous quenching at first,and then e...This paper deals with the quenching behavior of positive solutions to the Newton filtration equations coupled with boundary singularities.We determine quenching rates for non-simultaneous quenching at first,and then establish the criteria to identify the simultaneous and non-simultaneous quenching in terms of the parameters involved.展开更多
We study theoretically the features of the output field of a quadratically coupled optomechanical system assisted with three-level atoms. In this system, the atoms interact with the cavity field and are driven by a cl...We study theoretically the features of the output field of a quadratically coupled optomechanical system assisted with three-level atoms. In this system, the atoms interact with the cavity field and are driven by a classical field, and the cavity is driven by a strong coupling field and a weak signal field. We find that there exists a multi-window transparency phenomenon. The width of the transparent windows can be adjusted by controlling the system parameters, including the number of the atoms, the powers of the lasers driving the atoms and driving the cavity, and the environment temperature. We also find that a tunable switch from fast light to slow light can be realized in this system.展开更多
The presence of particles on the surface of a tunnel slope renders it susceptible to erosion by waterflow,which is a major cause of soil and water loss.In this study,a nonlinear mathematical model and a mechanical equi...The presence of particles on the surface of a tunnel slope renders it susceptible to erosion by waterflow,which is a major cause of soil and water loss.In this study,a nonlinear mathematical model and a mechanical equilibrium model are developed to investigate the distribution offlowfields and particle motion characteristics of tunnel slopes,respectively.The mathematical model offlowfields comprises three parts:a runoff region,a highly permeable soil layer,and a weakly permeable soil layer.The Navier‒Stokes equation controlsfluid motion in the runoff region,while the Brinkman-extended Darcy equation governs fast and slow seepage in the highly and weakly permeable soil layers,respectively.Analytical solutions are derived for the velocity profile and shear stress expression of the modelflowfield under the boundary condition of continuous transition of velocity and stress at thefluid‒solid interface.The shear stress distribution shows that the shear stress at the tunnel-slope surface is the largest,followed by the shear stress of the soil interface,indicating that particles in these two locations are most vulnerable to erosion.A mechanical equilibrium model of sliding and rolling of single particles is established at thefluid‒solid interface,and the safety factor of particle motion(sliding and rolling)is derived.Sensitivity analysis shows that by increasing the runoff depth,slope angle,and soil permeability,the erosion of soil particles will be aggravated on the tunnel-slope surface,but by increasing the particle diameter,particle-specific gravity,and particle stacking angle,the erosion resistance ability of the tunnel-slope surface particles will be enhanced.This study can serve as a reference for the analysis of surface soil and water loss in tunnel-slope systems.展开更多
The slow traffic system is an important component of urban transportation,and the prerequisite and necessary condition for Beijing to continue promoting“green priority”are establishing a good urban slow traffic syst...The slow traffic system is an important component of urban transportation,and the prerequisite and necessary condition for Beijing to continue promoting“green priority”are establishing a good urban slow traffic system.Shijingshan District of Beijing City is taken as a research object.By analyzing and processing population distribution data,POI data,and shared bicycle data,the shortcomings and deficiencies of the current slow traffic system in Shijingshan District are explored,and corresponding solutions are proposed,in order to provide new ideas and methods for future urban planning from the perspective of data.展开更多
Time-delay effects on synchronization features of delay-coupled slow-fast van der Pol systems are investigated in the present paper. The synchronization mechanism of “slow-manifold adjustment” is firstly described o...Time-delay effects on synchronization features of delay-coupled slow-fast van der Pol systems are investigated in the present paper. The synchronization mechanism of “slow-manifold adjustment” is firstly described on the basis of geometric singular perturbation theory. Then, the impact of time delay on the structure of the slow manifold of synchronized system is obtained by using the method of stability switch, and thus, time-delay effects on synchronization features are stated. It is shown the time delay cannot qualitatively affect the synchronization mechanism, however, it can result in the drift of the optimal coupling strength.展开更多
BACKGROUND The development of slow transit constipation(STC)is associated with intestinal barrier damage.Huangqi decoction(HQD)is effective in treating STC,but me-chanisms are unclear.AIM To investigate whether HQD al...BACKGROUND The development of slow transit constipation(STC)is associated with intestinal barrier damage.Huangqi decoction(HQD)is effective in treating STC,but me-chanisms are unclear.AIM To investigate whether HQD alleviates STC by downregulating the nuclear factorκB(NF-κB)signaling pathway and restoring intestinal barrier function.METHODS KM mice were divided into control,model,and HQD treatment groups.Fresh colonic tissues were collected for single-cell RNA sequencing and spatial tra-nscriptome sequencing.The expressions of claudin-1,mucin 2,and NF-κB P65 proteins were detected by immunohistochemistry.In vitro experiments evaluated the effects of HQD on the LS174T cell line.RESULTS HQD improved intestinal motility,restored mucosal epithelium function and morphology.Single-cell RNA sequencing and spatial transcriptome sequencing data showed a reduction in goblet cells,decreased mucin 2 secretion,and activated apoptotic pathways in STC mice.The population of intestinal stem cells was reduced,and proliferation along with Wnt/β-catenin pathways were inhibited.STC also altered the distribution of intestinal cell states,increasing immune-associated Enterocyte_C3.Aberrant NF-κB pathway activation was noted across various cell types.After HQD treatment,NF-κB pathway activity was down-regulated,while cell proliferation pathways were up-regulated,alongside an increase in Enterocyte_C1 related to material transport.Immunocytochemical,Western blot,and immunohistochemistry analyses confirmed NF-κB pathway activation in goblet cells of STC mice,with HQD inhibiting this aberrant activation.CONCLUSION STC involves intestinal mucosal barrier damage.HQD may treat STC by suppressing NF-κB signaling in epithelial cells,restoring intestinal epithelial cell function,and promoting mucosal barrier repair.展开更多
This paper studies chaotic motions in quasi-integrable Hamiltonian systems with slow-varying parameters under both harmonic and noise excitations. Based on the dynamic theory and some assumptions of excited noises, an...This paper studies chaotic motions in quasi-integrable Hamiltonian systems with slow-varying parameters under both harmonic and noise excitations. Based on the dynamic theory and some assumptions of excited noises, an extended form of the stochastic Melnikov method is presented. Using this extended method, the homoclinic bifurcations and chaotic behavior of a nonlinear Hamiltonian system with weak feed-back control under both harmonic and Gaussian white noise excitations are analyzed in detail. It is shown that the addition of stochastic excitations can make the parameter threshold value for the occurrence of chaotic motions vary in a wider region. Therefore, chaotic motions may arise easily in the system. By the Monte-Carlo method, the numerical results for the time-history and the maximum Lyapunov exponents of an example system are finally given to illustrate that the presented method is effective.展开更多
The Mg-Y-Zn magnesium alloy system is known for the presence of Long-Period Stacking Ordered(LPSO)phases that improves strength and ductility with minimal amounts of alloying elements.Even better improvements are asso...The Mg-Y-Zn magnesium alloy system is known for the presence of Long-Period Stacking Ordered(LPSO)phases that improves strength and ductility with minimal amounts of alloying elements.Even better improvements are associated with the specific microstructure known as the Mille-Feuille(MF)structure that can occur in this alloy as well after proper heat treatment.This study systematically compares the traditional ingot metallurgy method with the Bridgman method(slow cooling),coupled with diverse heat treatments and extrusion process.Microscopic analyses reveal variations in the presence of LPSO phases,MF structure,and especially grain size,leading to divergent mechanical and corrosion properties.The Bridgman approach surprisingly stands out,ensuring superior mechanical properties due to kink and texture strengthening.展开更多
Under the perspective of translation aesthetics,the article studies three Chinese-to-English translations of Slow,Slow Tune as research objects,comparing and contrasting the differences between the different translati...Under the perspective of translation aesthetics,the article studies three Chinese-to-English translations of Slow,Slow Tune as research objects,comparing and contrasting the differences between the different translations under the perspective of translation aesthetics.The study finds that:Kenneth Rexroth’s translation is poor in textual understanding,with a lot of errors,and is too shallow in emotional expression,remaining only on the surface of the text;Lin Yutang makes occasional mistakes in understanding individual words,and is able to explore the implicit feelings of the lyricist,and his translation focuses on textual and phonological beauty;Xu Yuanchong’s translation is not only capable of conveying the meaning of the original work,but also of conveying the lyricist’s feelings more vividly and focusing on the phonological beauty.Xu Yuanchong’s translation not only conveys the meaning of the original work,but also vividly conveys the emotion of the lyricist,and pays attention to the beauty of sound.展开更多
The March 11,2011,MW9.0 Tohoku-Oki earthquake,in Japan,caused rapid strain release near the epicenter,while the Boso Peninsula,located farther away,experienced stress redistribution,leading to changes in the recurrenc...The March 11,2011,MW9.0 Tohoku-Oki earthquake,in Japan,caused rapid strain release near the epicenter,while the Boso Peninsula,located farther away,experienced stress redistribution,leading to changes in the recurrence interval of slow slip events(SSEs)and regional strain.This study focuses on three detected post-2011 Boso SSEs,utilizing a segmented model displacement time series measured by Global Navigation Satellite System(GNSS)to calculate velocity and strain rate fields for eight periods before,during,and after the SSEs.Results show that the 2011 earthquake and the three SSEs significantly alter the velocity field in the Boso region,with SSE velocities predominantly oriented southeast,reaching maximum values of 26.9 cm/a,10.6 cm/a,and 38.5 cm/adnearly opposite to non-SSE periods.After the third SSE,the velocity field nearly returns to its pre-earthquake state,with a maximum of 1.8 cm/a.The maximum shear strain rates during the three SSEs are 25.88×10^(-7) a^(-1),11.38×10^(-7) a^(-1),and 29.02×10^(-7) a^(-1)(i.e.,per annum),significantly higher than those during non-slow slip periods,with principal strain rates following a similar pattern.The spatial distribution of strain rates during the SSEs indicates greater deformation compared to the non-slip periods,dominated by northwest-southeast extension and southwest-northeast compression.Spatiotemporal analysis reveals a strong correlation between seismic frequency and strain rate during the SSEs,with time correlation coefficients of 0.85,0.88,and 0.9.Although larger accumulated strain results in stronger strain release during the latter two SSEs,not all strain is fully released,suggesting that earthquake swarms accompanying the SSEs may contribute to the partial release of unreleased strain.This study,through the analysis of GNSS data,evaluates the spatiotemporal distribution of strain fields during periodic SSEs,contributing to further research on strain accumulation and release,and aiding in the analysis of this regional seismic activity.展开更多
基金supported by NSF (1620449)NSFC (11531006 and 11771449)
文摘We establish a slow manifold for a fast-slow dynamical system with anomalous diffusion,where both fast and slow components are influenced by white noise.Furthermore,we verify the exponential tracking property for the established random slow manifold,which leads to a lower dimensional reduced system.Alongside this we consider a parameter estimation method for a nonlocal fast-slow stochastic dynamical system,where only the slow component is observable.In terms of quantifying parameters in stochastic evolutionary systems,the provided method offers the advantage of dimension reduction.
基金the National Natural Science Foundation of China (Grant No. 62061028)the Opening Project of Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology (Grant No. ammt2021A4)+4 种基金the Foundation for Distinguished Young Scientists of Jiangxi Province (Grant No. 20162BCB23009)the Open Research Fund Program of the State Key Laboratory of LowDimensional Quantum Physics (Grant No. KF202010)the Interdisciplinary Innovation Fund of Nanchang University (Grant No. 9166-27060003-YB12)the Open Research Fund Program of Key Laboratory of Opto-Electronic Information Acquisition and Manipulation of Ministry of Education (Grant No. OEIAM202004)the Graduate Innovation Special Fund of Jiangxi Province (Grant No. YC2021-S054)。
文摘We theoretically explore the tunability of magnomechanically induced transparency(MMIT) phenomenon and fastslow light effect in a hybrid cavity magnomechanical system in which a high-quality yttrium iron garnet(YIG) sphere and an atomic ensemble are placed inside a microwave cavity. In the probe output spectrum, we can observe magnoninduced transparency(MIT) and MMIT due to the photon-magnon and phonon-magnon couplings. We further investigate the effect of atomic ensemble on the absorption spectrum. The results show that better transparency can be obtained by choosing appropriate atomic ensemble parameters. We give an explicit explanation for the mechanism of the Fano resonance phenomenon. Moreover, we discuss phenomena of slow-light propagation. The maximum group delay increases significantly with the increasing atom–cavity coupling strength, and the conversion between slow light and fast light can also be achieved by adjusting the atom–cavity coupling strength. These results may have potential applications for quantum information processing and high precision measurements.
基金Project supported by the National Natural Science Foundation of China for Outstanding Youth(Grant No.51622906)the National Natural Science Foundation of China(Grant No.51479173)+2 种基金the Fundamental Research Funds for the Central Universities(Grant No.201304030577)the Scientific Research Funds of Northwest A&F University(Grant No.2013BSJJ095)the Science Fund for Excellent Young Scholars from Northwest A&F University and Shaanxi Nova Program,China(Grant No.2016KJXX-55)
文摘Internal effects of the dynamic behaviors and nonlinear characteristics of a coupled fractional order hydropower generation system(HGS) are analyzed. A mathematical model of hydro-turbine governing system(HTGS) with rigid water hammer and hydro-turbine generator unit(HTGU) with fractional order damping forces are proposed. Based on Lagrange equations, a coupled fractional order HGS is established. Considering the dynamic transfer coefficient eis variational during the operation, introduced e as a periodic excitation into the HGS. The internal relationship of the dynamic behaviors between HTGS and HTGU is analyzed under different parameter values and fractional order. The results show obvious fast–slow dynamic behaviors in the HGS, causing corresponding vibration of the system, and some remarkable evolution phenomena take place with the changing of the periodic excitation parameter values.
基金supported by the National Natural Science Foundation of China(11032009 and 11272236)
文摘Flexible joints are usually used to transfer velocities in robot systems and may lead to delays in motion transformation due to joint flexibility. In this paper, a linkrotor structure connected by a flexible joint or shaft is firstly modeled to be a slow-fast delayed system when moment of inertia of the lightweight link is far less than that of the heavy rotor. To analyze the stability and oscillations of the slowfast system, the geometric singular perturbation method is extended, with both slow and fast manifolds expressed analytically. The stability of the slow manifold is investigated and critical boundaries are obtained to divide the stable and the unstable regions. To study effects of the transformation delay on the stability and oscillations of the link, two quantitatively different driving forces derived from the negative feedback of the link are considered. The results show that one of these two typical driving forces may drive the link to exhibit a stable state and the other kind of driving force may induce a relaxation oscillation for a very small delay. However, the link loses stability and undergoes regular periodic and bursting oscillation when the transformation delay is large. Basically, a very small delay does not affect the stability of the slow manifold but a large delay affects substantially.
基金sponsored by statutory research University of Science and Technology AGH,Cracow,Poland(No.11 100 281)
文摘In some worldwide hard coal basins recovery of methane from virgin coal beds is difficult. In general,mentioned difficulties are related to geo-mechanical, petrographical and physical-chemical properties of coals in question, occurring for example in the Bowen Basin(Australia) or the Upper Silesian Coal Basin(Poland). Among numerous properties and parameters, the following are very essential: susceptibility of coal beds to deformation connected with coal stress state change and contemporary shrinkage of the coal matrix during methane desorption. Those adverse geo-mechanical and physical-chemical effects are accompanied by essential change of the porous coal structure, which under these disadvantageous conditions is very complex. This study aims to show difficulties, which occur in phase of recognition of the methane-reach coal deposit. Volume absorbed methane(not surface adsorbed) in sub-micropores having minimal size comparable with gas molecule diameter must possess energy allowing separation of the nodes and methane release to micropores.
基金Project supported by the National Natural Science Foundation of China(Grant No.62061028)the Foundation for Distinguished Young Scientists of Jiangxi Province,China(Grant No.20162BCB23009)+2 种基金the Open Research Fund Program of the State Key Laboratory of Low-Dimensional Quantum Physics(Grant No.KF202010)the Interdisciplinary Innovation Fund of Nanchang University(Grant No.9166-27060003-YB12)the Open Research Fund Program of the Key Laboratory of Opto-Electronic Information Acquisition and Manipulation of Ministry of Education(Grant No.OEIAM202004).
文摘We theoretically explore the tunability of optomechanically induced transparency(OMIT)phenomenon and fast-slow light effect in a loop-coupled hybrid optomechanical system in which two optical modes are coupled to a common mechanical mode.In the probe output spectrum,we find that the interference phenomena OMIT caused by the optomechanical interactions and the normal mode splitting(NMS)induced by the strong tunnel coupling between the cavities can be observed.We further observe that the tunnel interaction will affect the distance and the heights of the sideband absorption peaks.The results also show that the switch from absorption to amplification can be realized by tuning the driving strength because of the existence of stability condition.Except from modulating the tunnel interaction,the conversion between slow light and fast light also can be achieved by adjusting the optomechanical interaction in the output field.This study may provide a potential application in the fields of high precision measurement and quantum information processing.
基金Sponsored by the National Natural Science Foundation of China (51708004)North China University of Technology YuY ou Talent Training Program (215051360020XN160/009)North China University of Technology Basal Research Fund (110052972027/154)。
文摘The urban slow traffic system refers to the traffic system in the city that can allow people to walk, ride, travel by bus and other slow travel. Through 4,728 papers on slow moving system in China from 2000 to 2020 included in CNKI, analysis and summary of literature publishing trend, research strength,research focus and development trend are conducted based on CiteSpace software. It is expected to provide reference for future research in this field.
文摘In this paper we will try to create, propose and analyze structure of a slow light device, based on plasmonic induced transparency in a metal-dielectric-metal based ring resonator. Group index by first design about 37 and second design about 35 earned. The proposed dielectric material is Poly Methyl Meta Acrylate (PMMA) sandwiched by gold metal cladding. Finite Element Method-con- ducted Electromagnetic simulations are employed to evaluate the plasmonic designs for behavior of slow light. The signal and pump wavelength are assumed to be 830 nm and 1550 nm respectively in the systems. The overall length of the plasmonic slow light system is 600 nm. In a wide range of frequency bands, the optical properties of metals can be described with a plasma model. The optical signal can be achieved with the use of surface waves on the boundary between the insulating materials and metals with dimensions smaller than the diffraction limit. The main goal, is estimation of optical characteristics such as bandwidth, the Real and Imaginary parts of refractive index, group velocity and slow down factor in such optical devices. The obtained results and observations, can be useful in basic research and the production of highly integrated plasmonic devices.
基金the financial support of the National Center for Scientific and Technical Research(CNRST)through the‘PhD-Associate Scholarship-PASS’program。
文摘We theoretically investigate the magnomechanically induced transparency phenomenon,Fano resonance and the slow-fast light effect in the situation where an atomic ensemble is placed inside the hybrid cavity of an optomagnomechanical system.The system is driven by dual optical and phononic drives.We show double magnomechanically induced transparency in the probe output spectrum by exploiting the phonon-photon coupling strength.Then,we study the effects of the decay rate of the cavity and the atomic ensemble on magnomechanically induced transparency.In addition,we demonstrate that effective detuning of the cavity field frequency changes the transparency window from a symmetrical to an asymmetrical profile,resembling Fano resonances.Further,the fast and slow light effects in the system are explored.We show that the slow light profile is enhanced by adjusting the phonon-photon coupling strength.This result may have potential applications in quantum information processing and communication.
基金supported by the National Nature Science Foundation of China (11372247 and 11102157)Program for NCET, the Shaanxi Project for Young New Star in Science and TechnologyNPU Foundation for Fundamental Research and SRF for ROCS, SEM
文摘A limit theorem which can simplify slow–fast dynamical systems driven by fractional Brownian motion with the Hurst parameter H inside the（1/2, 1） interval has been proved. The slow variables of the original system can be approximated by the solution of the simplified equations in the sense of mean square. An example is presented to illustrate the applications of the limit theorem.
基金Supported by the National Natural Science Foundation of China(10771024,11101060,11171048)
文摘This paper deals with the quenching behavior of positive solutions to the Newton filtration equations coupled with boundary singularities.We determine quenching rates for non-simultaneous quenching at first,and then establish the criteria to identify the simultaneous and non-simultaneous quenching in terms of the parameters involved.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61775062,11574092,61378012,91121023,and 60978009)the National Basic Research Program of China(Grant No.2013CB921804)
文摘We study theoretically the features of the output field of a quadratically coupled optomechanical system assisted with three-level atoms. In this system, the atoms interact with the cavity field and are driven by a classical field, and the cavity is driven by a strong coupling field and a weak signal field. We find that there exists a multi-window transparency phenomenon. The width of the transparent windows can be adjusted by controlling the system parameters, including the number of the atoms, the powers of the lasers driving the atoms and driving the cavity, and the environment temperature. We also find that a tunable switch from fast light to slow light can be realized in this system.
基金National Natural Science Foundation of China,Grant/Award Number:52109125Fundamental Research Funds for the Central Universities,Grant/Award Number:2023ZYGXZRx2tjD2231010Natural Science Foundation of Jiangsu Province,Grant/Award Number:BK20231217。
文摘The presence of particles on the surface of a tunnel slope renders it susceptible to erosion by waterflow,which is a major cause of soil and water loss.In this study,a nonlinear mathematical model and a mechanical equilibrium model are developed to investigate the distribution offlowfields and particle motion characteristics of tunnel slopes,respectively.The mathematical model offlowfields comprises three parts:a runoff region,a highly permeable soil layer,and a weakly permeable soil layer.The Navier‒Stokes equation controlsfluid motion in the runoff region,while the Brinkman-extended Darcy equation governs fast and slow seepage in the highly and weakly permeable soil layers,respectively.Analytical solutions are derived for the velocity profile and shear stress expression of the modelflowfield under the boundary condition of continuous transition of velocity and stress at thefluid‒solid interface.The shear stress distribution shows that the shear stress at the tunnel-slope surface is the largest,followed by the shear stress of the soil interface,indicating that particles in these two locations are most vulnerable to erosion.A mechanical equilibrium model of sliding and rolling of single particles is established at thefluid‒solid interface,and the safety factor of particle motion(sliding and rolling)is derived.Sensitivity analysis shows that by increasing the runoff depth,slope angle,and soil permeability,the erosion of soil particles will be aggravated on the tunnel-slope surface,but by increasing the particle diameter,particle-specific gravity,and particle stacking angle,the erosion resistance ability of the tunnel-slope surface particles will be enhanced.This study can serve as a reference for the analysis of surface soil and water loss in tunnel-slope systems.
基金Sponsored by Beijing Natural Science Foundation General Project(8212009)Construction of Philosophy and Social Sciences Base in Beijing-Research on Beijing Urban Renewal and Comprehensive Management of Old Community En-vironment2023 Education Reform Project of North China University of Technology(108051360023XN264-25).
文摘The slow traffic system is an important component of urban transportation,and the prerequisite and necessary condition for Beijing to continue promoting“green priority”are establishing a good urban slow traffic system.Shijingshan District of Beijing City is taken as a research object.By analyzing and processing population distribution data,POI data,and shared bicycle data,the shortcomings and deficiencies of the current slow traffic system in Shijingshan District are explored,and corresponding solutions are proposed,in order to provide new ideas and methods for future urban planning from the perspective of data.
文摘Time-delay effects on synchronization features of delay-coupled slow-fast van der Pol systems are investigated in the present paper. The synchronization mechanism of “slow-manifold adjustment” is firstly described on the basis of geometric singular perturbation theory. Then, the impact of time delay on the structure of the slow manifold of synchronized system is obtained by using the method of stability switch, and thus, time-delay effects on synchronization features are stated. It is shown the time delay cannot qualitatively affect the synchronization mechanism, however, it can result in the drift of the optimal coupling strength.
基金Supported by the Natural Science Foundation of Guangdong Province for Distinguished Young Scholars,No.2022B1515020003the National Natural Science Foundation of China,No.82174369,No.82405397,No.82374442,and No.81973847+2 种基金Postdoctoral Fellowship Program of CPSF No.GZC20233247National Key Clinical Disciplineand the Program of Guangdong Provincial Clinical Research Center for Digestive Diseases,No.2020B1111170004.
文摘BACKGROUND The development of slow transit constipation(STC)is associated with intestinal barrier damage.Huangqi decoction(HQD)is effective in treating STC,but me-chanisms are unclear.AIM To investigate whether HQD alleviates STC by downregulating the nuclear factorκB(NF-κB)signaling pathway and restoring intestinal barrier function.METHODS KM mice were divided into control,model,and HQD treatment groups.Fresh colonic tissues were collected for single-cell RNA sequencing and spatial tra-nscriptome sequencing.The expressions of claudin-1,mucin 2,and NF-κB P65 proteins were detected by immunohistochemistry.In vitro experiments evaluated the effects of HQD on the LS174T cell line.RESULTS HQD improved intestinal motility,restored mucosal epithelium function and morphology.Single-cell RNA sequencing and spatial transcriptome sequencing data showed a reduction in goblet cells,decreased mucin 2 secretion,and activated apoptotic pathways in STC mice.The population of intestinal stem cells was reduced,and proliferation along with Wnt/β-catenin pathways were inhibited.STC also altered the distribution of intestinal cell states,increasing immune-associated Enterocyte_C3.Aberrant NF-κB pathway activation was noted across various cell types.After HQD treatment,NF-κB pathway activity was down-regulated,while cell proliferation pathways were up-regulated,alongside an increase in Enterocyte_C1 related to material transport.Immunocytochemical,Western blot,and immunohistochemistry analyses confirmed NF-κB pathway activation in goblet cells of STC mice,with HQD inhibiting this aberrant activation.CONCLUSION STC involves intestinal mucosal barrier damage.HQD may treat STC by suppressing NF-κB signaling in epithelial cells,restoring intestinal epithelial cell function,and promoting mucosal barrier repair.
文摘This paper studies chaotic motions in quasi-integrable Hamiltonian systems with slow-varying parameters under both harmonic and noise excitations. Based on the dynamic theory and some assumptions of excited noises, an extended form of the stochastic Melnikov method is presented. Using this extended method, the homoclinic bifurcations and chaotic behavior of a nonlinear Hamiltonian system with weak feed-back control under both harmonic and Gaussian white noise excitations are analyzed in detail. It is shown that the addition of stochastic excitations can make the parameter threshold value for the occurrence of chaotic motions vary in a wider region. Therefore, chaotic motions may arise easily in the system. By the Monte-Carlo method, the numerical results for the time-history and the maximum Lyapunov exponents of an example system are finally given to illustrate that the presented method is effective.
基金supported by Japan Society for the Promotion of Science(KAKENHI Grant-in-Aid for Scientific Research,18H05475,18H05476 and JP20H00312)MRC International Collaborative Research Grant+4 种基金The authors would like to thank the Czech Science Foundation(Project No.22-22248S)specific university research(A1_FCHT_2024_007)for financial supportsupported by the Ministry of Education,Youth,and Sports of the Czech Republic.Project No.CZ.02.01.01/00/22_008/0004591co-funded by the European UnionCzechNanoLab project LM2023051 funded by MEYS CR is gratefully acknowledged for the financial support of the measurements/sample fabrication at LNSM Research Infrastructure。
文摘The Mg-Y-Zn magnesium alloy system is known for the presence of Long-Period Stacking Ordered(LPSO)phases that improves strength and ductility with minimal amounts of alloying elements.Even better improvements are associated with the specific microstructure known as the Mille-Feuille(MF)structure that can occur in this alloy as well after proper heat treatment.This study systematically compares the traditional ingot metallurgy method with the Bridgman method(slow cooling),coupled with diverse heat treatments and extrusion process.Microscopic analyses reveal variations in the presence of LPSO phases,MF structure,and especially grain size,leading to divergent mechanical and corrosion properties.The Bridgman approach surprisingly stands out,ensuring superior mechanical properties due to kink and texture strengthening.
文摘Under the perspective of translation aesthetics,the article studies three Chinese-to-English translations of Slow,Slow Tune as research objects,comparing and contrasting the differences between the different translations under the perspective of translation aesthetics.The study finds that:Kenneth Rexroth’s translation is poor in textual understanding,with a lot of errors,and is too shallow in emotional expression,remaining only on the surface of the text;Lin Yutang makes occasional mistakes in understanding individual words,and is able to explore the implicit feelings of the lyricist,and his translation focuses on textual and phonological beauty;Xu Yuanchong’s translation is not only capable of conveying the meaning of the original work,but also of conveying the lyricist’s feelings more vividly and focusing on the phonological beauty.Xu Yuanchong’s translation not only conveys the meaning of the original work,but also vividly conveys the emotion of the lyricist,and pays attention to the beauty of sound.
基金funded by the National Natural Science Foundation of China(41704031,42374040)the Natural Science Foundation of Jiangxi Science and Technology Department(20232BAB203073)the Key Laboratory of Mine Environmental Monitoring and Improving around Poyang Lake,Ministry of Natural Resources(MEMI-2021-2022-29).
文摘The March 11,2011,MW9.0 Tohoku-Oki earthquake,in Japan,caused rapid strain release near the epicenter,while the Boso Peninsula,located farther away,experienced stress redistribution,leading to changes in the recurrence interval of slow slip events(SSEs)and regional strain.This study focuses on three detected post-2011 Boso SSEs,utilizing a segmented model displacement time series measured by Global Navigation Satellite System(GNSS)to calculate velocity and strain rate fields for eight periods before,during,and after the SSEs.Results show that the 2011 earthquake and the three SSEs significantly alter the velocity field in the Boso region,with SSE velocities predominantly oriented southeast,reaching maximum values of 26.9 cm/a,10.6 cm/a,and 38.5 cm/adnearly opposite to non-SSE periods.After the third SSE,the velocity field nearly returns to its pre-earthquake state,with a maximum of 1.8 cm/a.The maximum shear strain rates during the three SSEs are 25.88×10^(-7) a^(-1),11.38×10^(-7) a^(-1),and 29.02×10^(-7) a^(-1)(i.e.,per annum),significantly higher than those during non-slow slip periods,with principal strain rates following a similar pattern.The spatial distribution of strain rates during the SSEs indicates greater deformation compared to the non-slip periods,dominated by northwest-southeast extension and southwest-northeast compression.Spatiotemporal analysis reveals a strong correlation between seismic frequency and strain rate during the SSEs,with time correlation coefficients of 0.85,0.88,and 0.9.Although larger accumulated strain results in stronger strain release during the latter two SSEs,not all strain is fully released,suggesting that earthquake swarms accompanying the SSEs may contribute to the partial release of unreleased strain.This study,through the analysis of GNSS data,evaluates the spatiotemporal distribution of strain fields during periodic SSEs,contributing to further research on strain accumulation and release,and aiding in the analysis of this regional seismic activity.
