We proposed and demonstrated the ultra-compact 1310/1550 nm wavelength multiplexer/demultiplexer assisted by subwavelength grating(SWG)using particle swarm optimization(PSO)algorithm in silicon-on-insulator(SOI)platfo...We proposed and demonstrated the ultra-compact 1310/1550 nm wavelength multiplexer/demultiplexer assisted by subwavelength grating(SWG)using particle swarm optimization(PSO)algorithm in silicon-on-insulator(SOI)platform.Through the self-imaging effect of multimode interference(MMI)coupler,the demultiplexing function for 1310 nm and 1550 nm wavelengths is implemented.After that,three parallel SWG-based slots are inserted into the MMI section so that the effective refractive index of the modes can be engineered and thus the beat length can be adjusted.Importantly,these three SWG slots significantly reduce the length of the device,which is much shorter than the length of traditional MMI-based wavelength demultiplexers.Ultimately,by using the PSO algorithm,the equivalent refractive index and width of the SWG in a certain range are optimized to achieve the best performance of the wavelength demultiplexer.It has been verified that the device footprint is only 2×30.68μm^(2),and 1 dB bandwidths of larger than 120 nm are acquired at 1310 nm and 1550 nm wavelengths.Meanwhile,the transmitted spectrum shows that the insertion loss(IL)values are below 0.47 dB at both wavelengths when the extinction ratio(ER)values are above 12.65 dB.This inverse design approach has been proved to be efficient in increasing bandwidth and reducing device length.展开更多
Quantum interference effect serves as a critical strategy for addressing incorrect energy level alignment between frontier molecular orbitals and electrodes in molecular junctions. Weak-coupling structures offer an ef...Quantum interference effect serves as a critical strategy for addressing incorrect energy level alignment between frontier molecular orbitals and electrodes in molecular junctions. Weak-coupling structures offer an effective approach to suppress phonon thermal conductance. The thermoelectric properties of pure C_(3)N_(4) nanoribbon devices and C_(3)N_(4)-C_(20) molecular junctions are systematically investigated based on density functional theory(DFT) combined with nonequilibrium Green's function(NEGF) formalism. The results show that pure C_(3)N_(4) nanoribbon devices have superior charge transport capabilities and excellent Seebeck coefficients. A remarkable thermoelectric figure of merit(ZT = 0.98)is achieved near 0.09 e V. The pronounced scattering effect induced by embedding a C_(20) molecule in the center of the C_(3)N_(4) nanoribbon significantly suppresses phonon transport. A maximum ZT value of 1.68 is observed at 0.987 e V. The electron mobility of C_(3)N_(4)-C_(20)-par is effectively increased due to quantum interference effect which greatly improves the alignment between the C_(20) molecule's frontier orbital energy level and C_(3)N_(4) electrodes. The C_(3)N_(4)-C_(20)-van der Waals(vd W) molecular junction allows very few phonons to pass through the C_(20) molecule from the left electrode to the right electrode. As a result, the C_(3)N_(4)-C_(20)-vd W junction achieves an excellent ZT value of 3.82 near the Femi level.展开更多
This paper realizes the full-domain collaborative deployment of multiple interference sources of the global satellite navigation system(GNSS)and evaluates the deployment effect to enhance the ability to disturb the at...This paper realizes the full-domain collaborative deployment of multiple interference sources of the global satellite navigation system(GNSS)and evaluates the deployment effect to enhance the ability to disturb the attacker and the capability to defend the GNSS during navigation countermeasures.Key evaluation indicators for the jamming effect of GNSS suppressive and deceptive jamming sources are first created,their evaluation models are built,and their detection procedures are sorted out,as the basis for determining the deployment principles.The principles for collaboratively deploying multi-jamming sources are developed to obtain the deployment structures(including the required number,structures in demand,and corresponding positions)of three single interference sources required by collaboratively deploying.Accordingly,simulation and hardware-in-loop testing results are presented to determine a rational configuration of the collaborative deployment of multi-jamming sources in the set situation and further realize the full-domain deployment of an interference network from ground,air to space.Varied evaluation indices for the deployment effect are finally developed to evaluate the deployment effect of the proposed configuration and further verify its reliability and rationality.展开更多
A vortex-induced vibration(VIV)experiment of rough risers with coupling interference effect under a side-by-side arrangement was carried out in a wave-current combined flume.The roughness of the riser was characterize...A vortex-induced vibration(VIV)experiment of rough risers with coupling interference effect under a side-by-side arrangement was carried out in a wave-current combined flume.The roughness of the riser was characterized by arranging different specifications of surface attachments on the surface of the riser.Rough risers with three different roughnesses were arranged side by side with smooth risers to explore the VIV response of the riser under the combined action of roughness and interference effect,and to reveal the coupling mechanism between roughness and interference effect.The experimental results show that,compared with that of a smooth riser,the VIV of a rough riser under the coupling interference effect has a wider"lock-in"region,and the displacement decreases more significantly at a high reduced velocity,which is more likely to excite higher-order modes and frequency responses.In addition,the displacement response and frequency response of the smooth riser are not significantly affected by wake interference from the rough riser,which is caused by the decrease of the wake region due to the delay of the boundary layer separation point of the rough riser.展开更多
In order to study the response law of vortex-induced vibration(VIV)of marine risers under the combined action of roughness and interference effects,and to reveal the coupling mechanism of roughness and interference ef...In order to study the response law of vortex-induced vibration(VIV)of marine risers under the combined action of roughness and interference effects,and to reveal the coupling mechanism of roughness and interference effects on the riser,a VIV experiment of rough risers in tandem arrangement was conducted in a wave−current combined flume.The experiment characterized the risers’roughness by arranging different specifications of attachments on the surface of the risers.Three rough risers with different roughness and smooth risers were arranged in tandem arrangement,with the rough risers arranged downstream.The experimental results indicate that the suppression of the attachments on the downstream risers’vibration are more significant both in the CF and IL directions as the reduced velocity increases.For the downstream riser,the amplitude response of rough riser is more significantly weakened compared with the smooth one at high reduced velocity.For the upstream risers,changes in the roughness and spacing ratio have an impact on their‘lock-in’region.When the roughness of downstream risers is relatively large(0.1300)and the spacing between risers is small(S/D=4.0),the reduced velocity range of‘lock-in’region in the CF direction of upstream risers is obviously expanded,and the displacement in the‘lock-in’region is severer.展开更多
The AB(Aharonov-Bohm)effect is a pivotal quantum mechanical phenomenon that illustrates the fundamental role of the electromagnetic vector potential A in determining the phase of a charged particle’s wave function,ev...The AB(Aharonov-Bohm)effect is a pivotal quantum mechanical phenomenon that illustrates the fundamental role of the electromagnetic vector potential A in determining the phase of a charged particle’s wave function,even in regions where the magnetic field B is zero.This effect demonstrates that quantum particles are influenced not only by the fields directly present but also by the potentials associated with those fields.In the AB effect,an electron beam is split into two paths,with one path encircling a solenoid and the other bypassing it.Despite the absence of a magnetic field in the regions traversed by the beams,the vector potential A associated with the magnetic flux Φ through the solenoid induces a phase shift in the electron’s wave function.This phase shift,quantified by △φ=qΦ/hc,manifests as a change in the interference pattern observed in the detection screen.The phenomenon underscores the principle of gauge invariance in QED(quantum electrodynamics),where physical observables remain invariant under local gauge transformations of the vector and scalar potentials.This reinforces the notion that the vector potential A has a profound impact on quantum systems,beyond its classical role.This article outlines the AB effect,including its theoretical framework,experimental observations,and implications.The focus on the role of the vector potential in quantum mechanics provides a comprehensive understanding of this important phenomenon.展开更多
Based on the effective structure of the self-mixing interference effects,a general model for the self-mixing interference effects in the LD pumped solid-state laser has been established for the first time.The numerica...Based on the effective structure of the self-mixing interference effects,a general model for the self-mixing interference effects in the LD pumped solid-state laser has been established for the first time.The numerical simulation of the self-mixing interference signal has been done,the results show that when the external cavity length is integral times of 1/2,1/3,2/3,1/4,3/4 of the effective cavity length,the intensity of the self-mixing interference signals reach maximum in value.While that of single mode laser is integral times of half of the effective cavity length,the measuring precision of displacement of single mode laser is λ/2.A conclusion can be drawn from the above results that the measuring precision of displacement of multi-mode laser is higher than that of single mode laser.展开更多
The combined and interactive effects of the bolt-hole fit conditions and the preloads of the fasteners on the load carrying capacity of single-lap composite-to-titanium bolted joints have been investigated both experi...The combined and interactive effects of the bolt-hole fit conditions and the preloads of the fasteners on the load carrying capacity of single-lap composite-to-titanium bolted joints have been investigated both experimentally and numerically. Quasi-static tests of the hybrid joints with different fit conditions are implemented, and a three dimensional finite element progressive failure analysis model is proposed to predict the influences of the bolt-hole fit conditions and fastener＇s pre- loads on the mechanical behaviors of the joints. Based on the experimental validated simulation method, a multi-factor, mixed levels orthogonal design table and the analysis of variance method are used to arrange the simulation conditions and to further study the interactive effects of preloads and fit conditions. Through the analysis of the results, for the researched double bolt, single-lap composite-titanium joints, it is found that： the effects of both the interference fit and the preloads change from positive into negative mode with the increase of the interference fit values or preload values; appropriate bolt-hole fit conditions and preloads can improve the bolt-hole contact conditions of the loaded joints, and then retard the fiber failures around the fastener holes, and increase the load carrying capacity of the joints eventually; the interactive effect of the bolt-hole interference fit conditions and preloads cannot be ignored and the parameters need to be considered together and synthetically as the joints are being optimized.展开更多
In this article, hybrid fillers with different dimensions, namely, 2-dimensional（2-D） expanded graphite（EG） and 1-dimensional（1-D） multi-walled carbon nanotubes（CNTs）, were added to aromatic nylon MXD6 matrix ...In this article, hybrid fillers with different dimensions, namely, 2-dimensional（2-D） expanded graphite（EG） and 1-dimensional（1-D） multi-walled carbon nanotubes（CNTs）, were added to aromatic nylon MXD6 matrix via melt-blending, to enhance its thermal and electrical conductivity as well as electromagnetic interference shielding effectiveness（EMI SE）. For ternary composites of MXD6/EG/CNTs, the electrical conductivity reaches up nine orders of magnitude higher compared to that of the neat MXD6 sample, which turned the polymer-based composites from an insulator to a conductor, and the thermal conductivity has been enhanced by 477% compared with that of neat MXD6 sample. Meanwhile, the EMI SE of ternary composite reaches ~50 d B at the overall filler loading of only 18 wt%. This work can provide guidance for the preparation of polymer composites with excellent thermal and electrical conductivity via using hybrid filler.展开更多
This paper reports the modeling method and outcomes of mechanical performance and damage evolution of single-lap bolted composite interference-fit joints under extreme temperatures.The anisotropic continuum damage mod...This paper reports the modeling method and outcomes of mechanical performance and damage evolution of single-lap bolted composite interference-fit joints under extreme temperatures.The anisotropic continuum damage model involving thermal effects is established on continuum damage mechanics which integrates the shear nonlinearity constitutive relations characterized by Romberg-Osgood equation.The temperature-induced modification of thermal strains and material properties is incorporated in stress-strain analysis,extended 3 D failure criteria and exponential damage evolution rules.The proposed model is calibrated and employed to simulate behavior of composite joints in interference fitting,bolt preloading,thermal and bearing loading processes,during which the influence of interference-fit sizes,preload levels,laminate layups and service temperatures is thoroughly investigated.The predicated interfacial behavior,bearing response and failure modes are in good agreement with experimental tests.The numerical model is even capable of reflecting some non-intuitive experimental findings such as residual stress relaxation and matrix softening at elevated temperatures.展开更多
Most previous investigations on interference effects of tall buildings under wind actions focused on the wind induced interference effects between two buildings,and the interference effects of three or more buildings ...Most previous investigations on interference effects of tall buildings under wind actions focused on the wind induced interference effects between two buildings,and the interference effects of three or more buildings have seldom been studied so far due to the huge workload involved in experiments and data processing.In this paper,mean and dynamic force/response interference effects and peak wind pressure interference effects of two and three tall buildings,especially the three-building configuration,are investigated through a series of wind tunnel tests on typical tall building models using high frequency force balance technique and wind pressure measurements.Furthermore,the present paper focuses on the effects of parameters,including breadth ratio and height ratio of the buildings and terrain category,on the interference factors and derives relevant regression results for the interference factors.展开更多
The Stokes polarimeter based on liquid crystal variable retarders(LCVRs)is envisaged as a promising novel technique for polarization measurement in space applications due to the inherent advantage of eliminating the n...The Stokes polarimeter based on liquid crystal variable retarders(LCVRs)is envisaged as a promising novel technique for polarization measurement in space applications due to the inherent advantage of eliminating the need for conventional rotating polarizing optics and increasing the measuring speed.However,the intrinsic multi-beam interference in LCVRs limits its polarization accuracy by several percent.How to eliminate the influence of the interference effect becomes an urgent issue for the liquid-crystal-based Stokes polarimeter.The present study introduces a simplified but effective interference model based on the thin-film optics and polarized light theory to simulate the relationship between the interference effect of the LCVRs-based Stokes polarimeter and the polarization accuracy.The simulation results show that the transmittance variation of LCVR with the derived voltage is caused by multi beam interference between the indium tin oxide(ITO)film and the liquid crystal within LCVR,which produces a few percent of instrumental polarization.The instrumental polarization is about 0.01 and different for different wavelengths.An optimization method was proposed to reduce the instrumental polarization to 0.002,effectively improving the polarization sensitivity of the Stokes polarimeter limited by the interference.In addition,an experimental setup was built up to measure and analyze the influence of the interference effect of the LCVRs-based Stokes polarimeter on the polarization accuracy before and after the optimization.The experiment results are in good agreement with the simulation.展开更多
The mean wind-induced interference effects between two high-rise buildings,in which the interfering buildings have different heights,were numerical simulated in the terrain roughness of B and D types by the Reynolds s...The mean wind-induced interference effects between two high-rise buildings,in which the interfering buildings have different heights,were numerical simulated in the terrain roughness of B and D types by the Reynolds stress equation model(RSM)of fluent.The results are in good agreement with those of the wind tunnel test.Influences of the relative arrangement of two buildings,the height of the interfering buildings and the terrain roughness upon the mean interference effects were analyzed,and the space distributions of IFCPs on the principal building under tandem arrangement were studied.The results indicate that the lower interfering buildings can always bring larger interference factors comparing to the higher ones under tandem arrangement except that the height is larger than 1.25h,and the heights' influence on the mean interference effects will increase as the reduced spacing of two buildings.The influence of heights will be little under stagger arrangement.展开更多
Multipath and continuous wave (CW) interference may cause severe performance degradation of global navigation satellite system (GNSS) receivers. This paper analyzes the code tracking performance of early-minus-late po...Multipath and continuous wave (CW) interference may cause severe performance degradation of global navigation satellite system (GNSS) receivers. This paper analyzes the code tracking performance of early-minus-late power (EMLP) discriminator of GNSS receivers in the presence of multipath and CW interference. An analytical expression of the code tracking error is suggested for EMLP discriminator, and it can be used to assess the effect of multipath and CW interference. The derived expression shows that the combined effects include three components: multipath component;CW interference component and the combined component of multipath and CW interference. The effect of these components depends on some factors which can be classified into two categories: the receiving environment and the receiver parameters. Numerical results show how these factors affect the tracking performances. It is shown that the proper receiver parameters can suppress the combined effects of multipath and CW interference.展开更多
Achieving excellent electromagnetic interference(EMI)shielding effectiveness(SE)in high rare earth(RE)-content Mg alloys is currently a significant technical challenge.This work systematically investigated the effects...Achieving excellent electromagnetic interference(EMI)shielding effectiveness(SE)in high rare earth(RE)-content Mg alloys is currently a significant technical challenge.This work systematically investigated the effects of different Nd elements on the electrical conductivity and EMI SE of Mg-12Gd-3Y-xNd alloy by adding Nd elements to the high RE content Mg-12Gd-3Y alloy,followed by a combined process of hot rolling and aging(R-A).The results indicate that the addition of Nd elements leads to reduced solid solubility of Gd and Y,resulting in a large amount of precipitation.The Mg-12Gd-3Y-2.0Nd alloy has the optimum EMI SE after 63%R-A treatment,reaching 88-118 dB at 30-1500 MHz.The Mg-12Gd-3Y-xNd alloy has acicular and granular forms of the Mg5(Gd,Y,Nd)(abbreviated as Mg5RE)phase after R-A treatment.The granular Mg5RE phase gradually breaks up and refines into more minor scales with increasing rolling reduction and is diffusely distributed in the matrix.The acicular Mg5RE phase is densely arranged,with cross-distribution in some areas.The cross-distributed acicular Mg5RE phase,the delicate granular Mg5RE phase,and the denseβ′phase provide more interfaces for reflecting electromagnetic waves and increase the multiple reflection loss of incident electromagnetic waves.In addition,the Mg-12Gd-3Y-xNd alloy deflects most of the c-axis of the grains parallel to the normal direction(ND)as the rolling reduction increases,making the impedance difference between the plate surface and air larger.The increased impedance makes the material reflect more loss to incident electromagnetic waves.The combined use of these two leads to an excellent EMI SE of Mg-12Gd-3Y-xNd with high RE content after R-A treatment.展开更多
Quantum cognition is a scientific approach to cognitive phenomena which makes use of the mathematical formalism of quantum theory. Quantum interference effect constitutes one of this theory’s main tenets and has been...Quantum cognition is a scientific approach to cognitive phenomena which makes use of the mathematical formalism of quantum theory. Quantum interference effect constitutes one of this theory’s main tenets and has been repeatedly demonstrated experimentally, in the last decade, in adult subjects. In the present paper, we aim to demonstrate, for the first time, the existence of thequantum interference effect on children during an experiment involving an integration of cognition and emotion. Our positive results consolidate the presuppositions of quantum cognition, enlarging its field of application to children’s mental apparatus and evidence the important question to consider the quantum model in the current investigated question of the interaction of cognition and emotion in children at neurological and psychological levels.展开更多
Through discussion of the time-distance curve characteristics of the direct waveand from the front,side and rear of the reflection waves of the seismic reflection methodfor advanced exploration in mines,and analysis o...Through discussion of the time-distance curve characteristics of the direct waveand from the front,side and rear of the reflection waves of the seismic reflection methodfor advanced exploration in mines,and analysis of several major interference waves inmines,the differences in time-distance curve,frequency,apparent velocity between theeffective wave and interference wave in the seismic reflection method for advanced explorationare obtained.According to the differences,the effective wave is extracted andthe interference wave is filtered and the system's precision and accuracy is improved.展开更多
Disturbance effect is one of the important factors for wind damage to large cooling towers.Existing studies on the wind-induced interference of cooling tower groups are aimed at the same size and the lack of wind-indu...Disturbance effect is one of the important factors for wind damage to large cooling towers.Existing studies on the wind-induced interference of cooling tower groups are aimed at the same size and the lack of wind-induced interference effects between cooling towers of different sizes.With the background of the additional cooling tower project at Shandong Luxi Power Plant in China,the rigid body pressure wind tunnel test is carried out to obtain 194 conditions for the three combinations of the existing four-tower combination(small size),the new two-tower combination(large size)and the six-tower combination surface wind pressure distribution.Numerical simulation of the surrounding flow field of the cooling tower group with the most unfavorable interference condition of the six-tower combination is conducted using the computational fluid dynamics(CFD)method.Based on this,the characteristics of the average and pulsating wind pressure distribution of the cooling tower surface under the six-tower combination are mainly studied,and the load interference coefficients of the large-sized cooling tower and the small-sized cooling tower under the three tower group combinations are compared.The velocity flow field and vorticity changes around the cooling tower group at unfavorable wind angles are analyzed,and the wind-induced interference mechanism between cooling tower groups of different sizes is mainly refined.Research shows that the interference effect between such cooling tower groups of different sizes is much larger than that of cooling tower groups of the same size,which is specifically manifested as the enhancement effect of small-sized cooling towers and the shielding effect of large-sized cooling towers.The interference coefficient of large-sized cooling tower groups increases by 28%,and the interference coefficient of small-sized cooling tower groups decreases by 6.4%.The airflow acceleration caused by the pinch effect between small-sized cooling tower groups has an adverse effect on large-sized cooling towers and can significantly increase the magnitude of local wind load.The shielding effect of large-sized cooling towers can reduce the overall wind load of small-sized cooling towers.The research conclusions can provide the basis of wind load value design for wind resistance design of such large cooling tower addition projects.展开更多
We investigate experimentally multi-orbital effects in high-order harmonic generation(HHG) from aligned CO2 and N2O molecules by intense femtosecond laser fields with linear and elliptical polarizations.For either of ...We investigate experimentally multi-orbital effects in high-order harmonic generation(HHG) from aligned CO2 and N2O molecules by intense femtosecond laser fields with linear and elliptical polarizations.For either of the aligned molecules, a minimum in the harmonic spectrum is observed, the position of which shifts to lower-order harmonics when decreasing the intensity or increasing the ellipticity of the driving laser.This indicates that the minimum originates from the dynamic interference of different channels, of which the tunneling ionization and recombination are contributed via different molecular orbitals.The results show that both the highest occupied molecular orbital(HOMO) and low-lying HOMO-2 in CO2(or HOMO-1 in N2O) contribute to the molecular HHG in both linearly and elliptically polarized strong laser fields.Our study would pave a way for understanding multi-electron dynamics from polyatomic molecules irradiated by strong laser fields.展开更多
The tunneling effect of Bose-Einstein condensate （BEC） in a harmonic trap with a Gaussian energy barrier is studied in this paper. The initial condensate evolves into two separate moving condensates after the tunnel...The tunneling effect of Bose-Einstein condensate （BEC） in a harmonic trap with a Gaussian energy barrier is studied in this paper. The initial condensate evolves into two separate moving condensates after the tunneling time under certain conditions. The interference pattern between the two moving condensates is given as a comparison and as a further demonstration of the existence of the global phase.展开更多
基金supported by the National Natural Science Foundation of China(No.61505160)the Innovation Capability Support Program of Shaanxi(No.2018KJXX-042)+2 种基金the Natural Science Basic Research Program of Shaanxi(No.2019JM-084)the State Key Laboratory of Transient Optics and Photonics(No.SKLST202108)the Graduate Innovation and Practical Ability Training Project of Xi’an Shiyou University(No.YCS22213190)。
文摘We proposed and demonstrated the ultra-compact 1310/1550 nm wavelength multiplexer/demultiplexer assisted by subwavelength grating(SWG)using particle swarm optimization(PSO)algorithm in silicon-on-insulator(SOI)platform.Through the self-imaging effect of multimode interference(MMI)coupler,the demultiplexing function for 1310 nm and 1550 nm wavelengths is implemented.After that,three parallel SWG-based slots are inserted into the MMI section so that the effective refractive index of the modes can be engineered and thus the beat length can be adjusted.Importantly,these three SWG slots significantly reduce the length of the device,which is much shorter than the length of traditional MMI-based wavelength demultiplexers.Ultimately,by using the PSO algorithm,the equivalent refractive index and width of the SWG in a certain range are optimized to achieve the best performance of the wavelength demultiplexer.It has been verified that the device footprint is only 2×30.68μm^(2),and 1 dB bandwidths of larger than 120 nm are acquired at 1310 nm and 1550 nm wavelengths.Meanwhile,the transmitted spectrum shows that the insertion loss(IL)values are below 0.47 dB at both wavelengths when the extinction ratio(ER)values are above 12.65 dB.This inverse design approach has been proved to be efficient in increasing bandwidth and reducing device length.
基金Project supported by the National Natural Science Foundation of China (Grant No. 12164046)。
文摘Quantum interference effect serves as a critical strategy for addressing incorrect energy level alignment between frontier molecular orbitals and electrodes in molecular junctions. Weak-coupling structures offer an effective approach to suppress phonon thermal conductance. The thermoelectric properties of pure C_(3)N_(4) nanoribbon devices and C_(3)N_(4)-C_(20) molecular junctions are systematically investigated based on density functional theory(DFT) combined with nonequilibrium Green's function(NEGF) formalism. The results show that pure C_(3)N_(4) nanoribbon devices have superior charge transport capabilities and excellent Seebeck coefficients. A remarkable thermoelectric figure of merit(ZT = 0.98)is achieved near 0.09 e V. The pronounced scattering effect induced by embedding a C_(20) molecule in the center of the C_(3)N_(4) nanoribbon significantly suppresses phonon transport. A maximum ZT value of 1.68 is observed at 0.987 e V. The electron mobility of C_(3)N_(4)-C_(20)-par is effectively increased due to quantum interference effect which greatly improves the alignment between the C_(20) molecule's frontier orbital energy level and C_(3)N_(4) electrodes. The C_(3)N_(4)-C_(20)-van der Waals(vd W) molecular junction allows very few phonons to pass through the C_(20) molecule from the left electrode to the right electrode. As a result, the C_(3)N_(4)-C_(20)-vd W junction achieves an excellent ZT value of 3.82 near the Femi level.
基金the National Natural Science Foundation of China(Grant No.42174047 and No.42174036)the National Science Foundation Project for Outstanding Youth(No.42104034).
文摘This paper realizes the full-domain collaborative deployment of multiple interference sources of the global satellite navigation system(GNSS)and evaluates the deployment effect to enhance the ability to disturb the attacker and the capability to defend the GNSS during navigation countermeasures.Key evaluation indicators for the jamming effect of GNSS suppressive and deceptive jamming sources are first created,their evaluation models are built,and their detection procedures are sorted out,as the basis for determining the deployment principles.The principles for collaboratively deploying multi-jamming sources are developed to obtain the deployment structures(including the required number,structures in demand,and corresponding positions)of three single interference sources required by collaboratively deploying.Accordingly,simulation and hardware-in-loop testing results are presented to determine a rational configuration of the collaborative deployment of multi-jamming sources in the set situation and further realize the full-domain deployment of an interference network from ground,air to space.Varied evaluation indices for the deployment effect are finally developed to evaluate the deployment effect of the proposed configuration and further verify its reliability and rationality.
基金financially supported by the Natural Science Foundation of Shandong Province(Grant Nos.ZR2023ME040 and ZR2022QE118)the Key Technology Research and Development Program of Shandong Province(Grant No.2023CXGC010316)+1 种基金the Natural Science Foundation of Qingdao(Grant No.23-2-1-207-zyyd-jch)the Introduction and Education Plan for Young Innovative talents in Colleges and Universities of Shandong Province(Marine Civil Engineering Materials and Structure Innovation Research Team).
文摘A vortex-induced vibration(VIV)experiment of rough risers with coupling interference effect under a side-by-side arrangement was carried out in a wave-current combined flume.The roughness of the riser was characterized by arranging different specifications of surface attachments on the surface of the riser.Rough risers with three different roughnesses were arranged side by side with smooth risers to explore the VIV response of the riser under the combined action of roughness and interference effect,and to reveal the coupling mechanism between roughness and interference effect.The experimental results show that,compared with that of a smooth riser,the VIV of a rough riser under the coupling interference effect has a wider"lock-in"region,and the displacement decreases more significantly at a high reduced velocity,which is more likely to excite higher-order modes and frequency responses.In addition,the displacement response and frequency response of the smooth riser are not significantly affected by wake interference from the rough riser,which is caused by the decrease of the wake region due to the delay of the boundary layer separation point of the rough riser.
基金supported by the Natural Science Foundation of Shandong Province(Grant Nos.ZR2023ME040 and ZR2022QE118)the Key Technology Research and Development Program of Shandong Province(Grant No.2023CXGC010316)the Natural Science Foundation of Qingdao(Grant No.23-2-1-207-zyyd-jch),and the National Natural Science Foundation of China(Grant No.51709161).
文摘In order to study the response law of vortex-induced vibration(VIV)of marine risers under the combined action of roughness and interference effects,and to reveal the coupling mechanism of roughness and interference effects on the riser,a VIV experiment of rough risers in tandem arrangement was conducted in a wave−current combined flume.The experiment characterized the risers’roughness by arranging different specifications of attachments on the surface of the risers.Three rough risers with different roughness and smooth risers were arranged in tandem arrangement,with the rough risers arranged downstream.The experimental results indicate that the suppression of the attachments on the downstream risers’vibration are more significant both in the CF and IL directions as the reduced velocity increases.For the downstream riser,the amplitude response of rough riser is more significantly weakened compared with the smooth one at high reduced velocity.For the upstream risers,changes in the roughness and spacing ratio have an impact on their‘lock-in’region.When the roughness of downstream risers is relatively large(0.1300)and the spacing between risers is small(S/D=4.0),the reduced velocity range of‘lock-in’region in the CF direction of upstream risers is obviously expanded,and the displacement in the‘lock-in’region is severer.
文摘The AB(Aharonov-Bohm)effect is a pivotal quantum mechanical phenomenon that illustrates the fundamental role of the electromagnetic vector potential A in determining the phase of a charged particle’s wave function,even in regions where the magnetic field B is zero.This effect demonstrates that quantum particles are influenced not only by the fields directly present but also by the potentials associated with those fields.In the AB effect,an electron beam is split into two paths,with one path encircling a solenoid and the other bypassing it.Despite the absence of a magnetic field in the regions traversed by the beams,the vector potential A associated with the magnetic flux Φ through the solenoid induces a phase shift in the electron’s wave function.This phase shift,quantified by △φ=qΦ/hc,manifests as a change in the interference pattern observed in the detection screen.The phenomenon underscores the principle of gauge invariance in QED(quantum electrodynamics),where physical observables remain invariant under local gauge transformations of the vector and scalar potentials.This reinforces the notion that the vector potential A has a profound impact on quantum systems,beyond its classical role.This article outlines the AB effect,including its theoretical framework,experimental observations,and implications.The focus on the role of the vector potential in quantum mechanics provides a comprehensive understanding of this important phenomenon.
文摘Based on the effective structure of the self-mixing interference effects,a general model for the self-mixing interference effects in the LD pumped solid-state laser has been established for the first time.The numerical simulation of the self-mixing interference signal has been done,the results show that when the external cavity length is integral times of 1/2,1/3,2/3,1/4,3/4 of the effective cavity length,the intensity of the self-mixing interference signals reach maximum in value.While that of single mode laser is integral times of half of the effective cavity length,the measuring precision of displacement of single mode laser is λ/2.A conclusion can be drawn from the above results that the measuring precision of displacement of multi-mode laser is higher than that of single mode laser.
文摘The combined and interactive effects of the bolt-hole fit conditions and the preloads of the fasteners on the load carrying capacity of single-lap composite-to-titanium bolted joints have been investigated both experimentally and numerically. Quasi-static tests of the hybrid joints with different fit conditions are implemented, and a three dimensional finite element progressive failure analysis model is proposed to predict the influences of the bolt-hole fit conditions and fastener＇s pre- loads on the mechanical behaviors of the joints. Based on the experimental validated simulation method, a multi-factor, mixed levels orthogonal design table and the analysis of variance method are used to arrange the simulation conditions and to further study the interactive effects of preloads and fit conditions. Through the analysis of the results, for the researched double bolt, single-lap composite-titanium joints, it is found that： the effects of both the interference fit and the preloads change from positive into negative mode with the increase of the interference fit values or preload values; appropriate bolt-hole fit conditions and preloads can improve the bolt-hole contact conditions of the loaded joints, and then retard the fiber failures around the fastener holes, and increase the load carrying capacity of the joints eventually; the interactive effect of the bolt-hole interference fit conditions and preloads cannot be ignored and the parameters need to be considered together and synthetically as the joints are being optimized.
基金financially supported by the National Natural Science Foundation of China(Nos.21274095 and 51573102)
文摘In this article, hybrid fillers with different dimensions, namely, 2-dimensional（2-D） expanded graphite（EG） and 1-dimensional（1-D） multi-walled carbon nanotubes（CNTs）, were added to aromatic nylon MXD6 matrix via melt-blending, to enhance its thermal and electrical conductivity as well as electromagnetic interference shielding effectiveness（EMI SE）. For ternary composites of MXD6/EG/CNTs, the electrical conductivity reaches up nine orders of magnitude higher compared to that of the neat MXD6 sample, which turned the polymer-based composites from an insulator to a conductor, and the thermal conductivity has been enhanced by 477% compared with that of neat MXD6 sample. Meanwhile, the EMI SE of ternary composite reaches ~50 d B at the overall filler loading of only 18 wt%. This work can provide guidance for the preparation of polymer composites with excellent thermal and electrical conductivity via using hybrid filler.
基金finically supported by Joint Found for Equipment Advance Research and Aerospace Science and Technology of China(No.6141B061401)Fund for Distinguished Young Scholars in Shaanxi Province of China(No.2018-JC-009)。
文摘This paper reports the modeling method and outcomes of mechanical performance and damage evolution of single-lap bolted composite interference-fit joints under extreme temperatures.The anisotropic continuum damage model involving thermal effects is established on continuum damage mechanics which integrates the shear nonlinearity constitutive relations characterized by Romberg-Osgood equation.The temperature-induced modification of thermal strains and material properties is incorporated in stress-strain analysis,extended 3 D failure criteria and exponential damage evolution rules.The proposed model is calibrated and employed to simulate behavior of composite joints in interference fitting,bolt preloading,thermal and bearing loading processes,during which the influence of interference-fit sizes,preload levels,laminate layups and service temperatures is thoroughly investigated.The predicated interfacial behavior,bearing response and failure modes are in good agreement with experimental tests.The numerical model is even capable of reflecting some non-intuitive experimental findings such as residual stress relaxation and matrix softening at elevated temperatures.
基金supported by the National Natural Science Foundation of China (90715040)
文摘Most previous investigations on interference effects of tall buildings under wind actions focused on the wind induced interference effects between two buildings,and the interference effects of three or more buildings have seldom been studied so far due to the huge workload involved in experiments and data processing.In this paper,mean and dynamic force/response interference effects and peak wind pressure interference effects of two and three tall buildings,especially the three-building configuration,are investigated through a series of wind tunnel tests on typical tall building models using high frequency force balance technique and wind pressure measurements.Furthermore,the present paper focuses on the effects of parameters,including breadth ratio and height ratio of the buildings and terrain category,on the interference factors and derives relevant regression results for the interference factors.
基金Project supported by the Strategic Pioneer Program on Space Science,Chinese Academy of Sciences(Grant Nos.XDA15010800 and XDA15320102)the National Natural Science Foundation of China(Grant Nos.11427901,11773040,11403047,and 11427803)。
文摘The Stokes polarimeter based on liquid crystal variable retarders(LCVRs)is envisaged as a promising novel technique for polarization measurement in space applications due to the inherent advantage of eliminating the need for conventional rotating polarizing optics and increasing the measuring speed.However,the intrinsic multi-beam interference in LCVRs limits its polarization accuracy by several percent.How to eliminate the influence of the interference effect becomes an urgent issue for the liquid-crystal-based Stokes polarimeter.The present study introduces a simplified but effective interference model based on the thin-film optics and polarized light theory to simulate the relationship between the interference effect of the LCVRs-based Stokes polarimeter and the polarization accuracy.The simulation results show that the transmittance variation of LCVR with the derived voltage is caused by multi beam interference between the indium tin oxide(ITO)film and the liquid crystal within LCVR,which produces a few percent of instrumental polarization.The instrumental polarization is about 0.01 and different for different wavelengths.An optimization method was proposed to reduce the instrumental polarization to 0.002,effectively improving the polarization sensitivity of the Stokes polarimeter limited by the interference.In addition,an experimental setup was built up to measure and analyze the influence of the interference effect of the LCVRs-based Stokes polarimeter on the polarization accuracy before and after the optimization.The experiment results are in good agreement with the simulation.
基金the National Natural Science Foundation of China(Grant No.59895410)
文摘The mean wind-induced interference effects between two high-rise buildings,in which the interfering buildings have different heights,were numerical simulated in the terrain roughness of B and D types by the Reynolds stress equation model(RSM)of fluent.The results are in good agreement with those of the wind tunnel test.Influences of the relative arrangement of two buildings,the height of the interfering buildings and the terrain roughness upon the mean interference effects were analyzed,and the space distributions of IFCPs on the principal building under tandem arrangement were studied.The results indicate that the lower interfering buildings can always bring larger interference factors comparing to the higher ones under tandem arrangement except that the height is larger than 1.25h,and the heights' influence on the mean interference effects will increase as the reduced spacing of two buildings.The influence of heights will be little under stagger arrangement.
文摘Multipath and continuous wave (CW) interference may cause severe performance degradation of global navigation satellite system (GNSS) receivers. This paper analyzes the code tracking performance of early-minus-late power (EMLP) discriminator of GNSS receivers in the presence of multipath and CW interference. An analytical expression of the code tracking error is suggested for EMLP discriminator, and it can be used to assess the effect of multipath and CW interference. The derived expression shows that the combined effects include three components: multipath component;CW interference component and the combined component of multipath and CW interference. The effect of these components depends on some factors which can be classified into two categories: the receiving environment and the receiver parameters. Numerical results show how these factors affect the tracking performances. It is shown that the proper receiver parameters can suppress the combined effects of multipath and CW interference.
基金financially supported by the National Key R&D Program of China(2021YFB3701100)the National Natural Science Foundation of China(52225101 and 52171103)the Fundamental Research Funds for the Central Universities(2020CDJDPT001).
文摘Achieving excellent electromagnetic interference(EMI)shielding effectiveness(SE)in high rare earth(RE)-content Mg alloys is currently a significant technical challenge.This work systematically investigated the effects of different Nd elements on the electrical conductivity and EMI SE of Mg-12Gd-3Y-xNd alloy by adding Nd elements to the high RE content Mg-12Gd-3Y alloy,followed by a combined process of hot rolling and aging(R-A).The results indicate that the addition of Nd elements leads to reduced solid solubility of Gd and Y,resulting in a large amount of precipitation.The Mg-12Gd-3Y-2.0Nd alloy has the optimum EMI SE after 63%R-A treatment,reaching 88-118 dB at 30-1500 MHz.The Mg-12Gd-3Y-xNd alloy has acicular and granular forms of the Mg5(Gd,Y,Nd)(abbreviated as Mg5RE)phase after R-A treatment.The granular Mg5RE phase gradually breaks up and refines into more minor scales with increasing rolling reduction and is diffusely distributed in the matrix.The acicular Mg5RE phase is densely arranged,with cross-distribution in some areas.The cross-distributed acicular Mg5RE phase,the delicate granular Mg5RE phase,and the denseβ′phase provide more interfaces for reflecting electromagnetic waves and increase the multiple reflection loss of incident electromagnetic waves.In addition,the Mg-12Gd-3Y-xNd alloy deflects most of the c-axis of the grains parallel to the normal direction(ND)as the rolling reduction increases,making the impedance difference between the plate surface and air larger.The increased impedance makes the material reflect more loss to incident electromagnetic waves.The combined use of these two leads to an excellent EMI SE of Mg-12Gd-3Y-xNd with high RE content after R-A treatment.
文摘Quantum cognition is a scientific approach to cognitive phenomena which makes use of the mathematical formalism of quantum theory. Quantum interference effect constitutes one of this theory’s main tenets and has been repeatedly demonstrated experimentally, in the last decade, in adult subjects. In the present paper, we aim to demonstrate, for the first time, the existence of thequantum interference effect on children during an experiment involving an integration of cognition and emotion. Our positive results consolidate the presuppositions of quantum cognition, enlarging its field of application to children’s mental apparatus and evidence the important question to consider the quantum model in the current investigated question of the interaction of cognition and emotion in children at neurological and psychological levels.
基金Supported by the National Natural Science Foundation of China(50375026)the National Basic Research Program of China(2005cb221500)+1 种基金the National Key Technology R&D Program(2006BAK03B01)the National Natural Science Foundation Key Program(50534080)
文摘Through discussion of the time-distance curve characteristics of the direct waveand from the front,side and rear of the reflection waves of the seismic reflection methodfor advanced exploration in mines,and analysis of several major interference waves inmines,the differences in time-distance curve,frequency,apparent velocity between theeffective wave and interference wave in the seismic reflection method for advanced explorationare obtained.According to the differences,the effective wave is extracted andthe interference wave is filtered and the system's precision and accuracy is improved.
基金supported in part by the National Natural Science Foundations(Nos. 51878351, U1733129,51761165022)the Outstanding Youth Fund of Jiangsu Natural Science Foundation(No. BK20160083).
文摘Disturbance effect is one of the important factors for wind damage to large cooling towers.Existing studies on the wind-induced interference of cooling tower groups are aimed at the same size and the lack of wind-induced interference effects between cooling towers of different sizes.With the background of the additional cooling tower project at Shandong Luxi Power Plant in China,the rigid body pressure wind tunnel test is carried out to obtain 194 conditions for the three combinations of the existing four-tower combination(small size),the new two-tower combination(large size)and the six-tower combination surface wind pressure distribution.Numerical simulation of the surrounding flow field of the cooling tower group with the most unfavorable interference condition of the six-tower combination is conducted using the computational fluid dynamics(CFD)method.Based on this,the characteristics of the average and pulsating wind pressure distribution of the cooling tower surface under the six-tower combination are mainly studied,and the load interference coefficients of the large-sized cooling tower and the small-sized cooling tower under the three tower group combinations are compared.The velocity flow field and vorticity changes around the cooling tower group at unfavorable wind angles are analyzed,and the wind-induced interference mechanism between cooling tower groups of different sizes is mainly refined.Research shows that the interference effect between such cooling tower groups of different sizes is much larger than that of cooling tower groups of the same size,which is specifically manifested as the enhancement effect of small-sized cooling towers and the shielding effect of large-sized cooling towers.The interference coefficient of large-sized cooling tower groups increases by 28%,and the interference coefficient of small-sized cooling tower groups decreases by 6.4%.The airflow acceleration caused by the pinch effect between small-sized cooling tower groups has an adverse effect on large-sized cooling towers and can significantly increase the magnitude of local wind load.The shielding effect of large-sized cooling towers can reduce the overall wind load of small-sized cooling towers.The research conclusions can provide the basis of wind load value design for wind resistance design of such large cooling tower addition projects.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.91750104,11534004,11874179,11127403,11474130)the Natural Science Foundation of Jilin Province,China(Grant No.20180101289JC)
文摘We investigate experimentally multi-orbital effects in high-order harmonic generation(HHG) from aligned CO2 and N2O molecules by intense femtosecond laser fields with linear and elliptical polarizations.For either of the aligned molecules, a minimum in the harmonic spectrum is observed, the position of which shifts to lower-order harmonics when decreasing the intensity or increasing the ellipticity of the driving laser.This indicates that the minimum originates from the dynamic interference of different channels, of which the tunneling ionization and recombination are contributed via different molecular orbitals.The results show that both the highest occupied molecular orbital(HOMO) and low-lying HOMO-2 in CO2(or HOMO-1 in N2O) contribute to the molecular HHG in both linearly and elliptically polarized strong laser fields.Our study would pave a way for understanding multi-electron dynamics from polyatomic molecules irradiated by strong laser fields.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10974068)
文摘The tunneling effect of Bose-Einstein condensate （BEC） in a harmonic trap with a Gaussian energy barrier is studied in this paper. The initial condensate evolves into two separate moving condensates after the tunneling time under certain conditions. The interference pattern between the two moving condensates is given as a comparison and as a further demonstration of the existence of the global phase.
