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
Interference effects on the photoionization cross sections between two neighbouring atoms are considered based on the coherent scattering of the ionized electrons by the two nuclei when their separation is less than o...Interference effects on the photoionization cross sections between two neighbouring atoms are considered based on the coherent scattering of the ionized electrons by the two nuclei when their separation is less than or comparable to the de Broglie wave length of the ionized electrons. As an example, the single atomic nitrogen ionization cross section and the total cross sections of two nitrogen atoms with coherently added photoionization amplitudes are calculated from the threshold to about А (1 А=0.1 nm) of the photon energy. The photoionization cross sections of atomic nitrogen are obtained by using the close-coupling R-matrix method. In the calculation 19 states are included. The ionization energy of the atomic nitrogen and the photoionization cross sections agree well with the experimental results. Based on the R-matrix results of atomic nitrogen, the interference effects between two neighbouring nitrogen atoms are obtained. It is shown that the interference effects are considerable when electrons are ionized just above the threshold, even for the separations between the two atoms are larger than two times of the bond length of N2 molecules. Therefore, in hot and dense samples, effects caused by the coherent interference between the neighbours are expected to be observable for the total photoionization cross sections.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
The aerodynamic interference effects on aero-static coefficients of twin deck bridges with large span were investigated in detail by means of wind tunnel test.The distances between the twin decks and wind attack angle...The aerodynamic interference effects on aero-static coefficients of twin deck bridges with large span were investigated in detail by means of wind tunnel test.The distances between the twin decks and wind attack angles were changed during the wind tunnel test to study the effects on aerodynamic interferences of aerostatic coefficients of twin decks.The research results have shown that the drag coefficients of the leeward deck are much smaller than that of a single leeward deck.The drag coefficients of a windward deck decrease slightly com-pared with that of a single deck.The lift and torque coefficients of windward and leeward decks are also affected slightly by the aerodynamic interference of twin decks.And the aerodynamic interference effects on lift and torque coefficients of twin decks can be neglected.展开更多
We calculate the spinor helicity amplitudes of anomalous H→ZZ→4ℓdecay.After embedding these analytic formulas into the MCFM package,we study the interference effects between the anomalous gg→H→ZZ→4ℓprocess and th...We calculate the spinor helicity amplitudes of anomalous H→ZZ→4ℓdecay.After embedding these analytic formulas into the MCFM package,we study the interference effects between the anomalous gg→H→ZZ→4ℓprocess and the SM processes,which are indispensable in the Higgs off-shell region.Subsequently,the constraints on the anomalous couplings are estimated using LHC experimental data.展开更多
A high luminosity Circular Electron Positron Collider(CEPC) as a Higgs Factory will be helpful for precision measurements of the Higgs mass. The signal-background interference effect is carefully studied for the Hig...A high luminosity Circular Electron Positron Collider(CEPC) as a Higgs Factory will be helpful for precision measurements of the Higgs mass. The signal-background interference effect is carefully studied for the Higgs diphoton decay mode in associated Z boson production at future e^+e^-colliders at energy 246 GeV. The mass shifts go up from about 20 MeV to 50 MeV for the experimental mass resolution ranging from 0.8 GeV to 2 GeV.展开更多
A partition model of interference efficiency was constructed to study the coupling interference effect under combined internal and external flow.The concept of“internal flow efficiency”,“velocity ratio”and“interf...A partition model of interference efficiency was constructed to study the coupling interference effect under combined internal and external flow.The concept of“internal flow efficiency”,“velocity ratio”and“interference efficiency”were introduced to quantify the effect of internal flow and interference,and reveal the coupling mechanism among internal flow,external flow and interference effect.The results showed that the dynamic response of risers under variable angles was significantly different after considering the effect of internal flow.When the external flow velocity was smaller than 0.25 m/s,the vibration of risers was promoted by the internal flow.With the increase of external flow velocity,the effect of internal flow was weakened and the dynamic response of riser mainly depended on the external flow and interference effect.Under the effect of different internal flow,the interference efficiency had similar change trend.The interference effect amplified the complex secondary flow effect inside the riser,making the dynamic response of riser complex and random.In this paper,the overlap area and subdivision criterion of interference effect were constructed within the range of experimental velocity ratio,and the change curve of interference efficiency was obtained with an average meaning,which may have important practical meaning.展开更多
The“riser group−fluid between risers”is taken as the carrier,and the experiment on vortex-induced vibration of tandem riser groups coupling interference effect under sensitive spacing is performed.The least-square m...The“riser group−fluid between risers”is taken as the carrier,and the experiment on vortex-induced vibration of tandem riser groups coupling interference effect under sensitive spacing is performed.The least-square method is used to linearly fit the reduced velocity and main frequency,and the rule of Strouhal numbers is analyzed.Each mode is separated based on the mode decomposition theory,and the mode conversion mechanism is also explored.The concept of“interference efficiency”is introduced to study the dynamic characteristics and response evolutions of different riser groups.The results show that the wake shielding effect widely exists in tandem riser groups,and the interference effect of midstream and downstream risers on their upstream risers is significantly lower than that of upstream risers on midstream and downstream risers.The trajectories of midstream and downstream risers lag behind their upstream risers due to multiple shadowing effects,the vibration frequency range of downstream riser is widened and the dominant frequency is extremely unstable.Compared with the isolated riser,wake interference suppresses the vibration dis-placement of the midstream and downstream risers in the in-line direction,and enhances the displacement of upstream and midstream risers in the cross-flow direction.The interference effect of the fluid between risers at low velocities is stronger than that at higher velocities,and the cross-flow displacements of upstream risers are always in the interference enhancement region.It is urgent to pay attention to the cross-flow displacement of upstream and midstream risers in tandem riser groups considering the safety design.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 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
Inspired by a recent experiment[Phys.Rev.Lett.122253201(2019)]that an unprecedented quantum interference was observed in the way of stimulated Raman adiabatic passage(STIRAP)due to the coexisting resonant-and detuned-...Inspired by a recent experiment[Phys.Rev.Lett.122253201(2019)]that an unprecedented quantum interference was observed in the way of stimulated Raman adiabatic passage(STIRAP)due to the coexisting resonant-and detuned-STIRAPs,we comprehensively study this effect.Our results uncover the scheme robustness towards any external-field fluctuations coming from laser intensity noise and imperfect resonance condition,as well as the persistence of high-contrast interference pattern even when more nearby excited levels are involved.We verify that an auxiliary dynamical phase accumulated in hold time caused by the presence of the quasi-dark state in detuned-STIRAP can sensitively manipulate the visibility and frequency of the interference pattern,representing a new hallmark to measure the hyperfine energy accurately.The robust stability of the scheme comes from the intrinsic superiority embedded in the STIRAP mechanism that preserves the coherence of population transfer,which promises a remarkable performance of quantum interference in a practical implementation.展开更多
The phenomena of interference in the course of assembling curved bevel gears are ana. lysed and the corresponding prediction program of interference is established taking KlingInberg bevel gear as an exmple....The phenomena of interference in the course of assembling curved bevel gears are ana. lysed and the corresponding prediction program of interference is established taking KlingInberg bevel gear as an exmple. The factors influencing interferenee are discussed and the coneept ofcritical cutter radius is proposed. Finally, a simplified approximate function between the critical cutter ra- dius and the other factors is derived,and the designing method of avoiding interferenee is provided. The analysis and caiculation are proved to consistent with a case of actual product.展开更多
The cylindrical reticulated shell structures without side walls, which are normally arranged in pairs, are usually used as dry-coal sheds in a thermal power plant. The wind loads of these shells do not exist in standa...The cylindrical reticulated shell structures without side walls, which are normally arranged in pairs, are usually used as dry-coal sheds in a thermal power plant. The wind loads of these shells do not exist in standards or codes. Therefore, this study investigates the mean and fluctuating wind loads on a cylindrical reticulated shell with a rise-to-span ratio of 0.39 through a series of wind tunnel tests. The characteristics of the wind pressures on the upper and lower surfaces and the net pressures are presented. The results show that the wind direction and another shell structure significantly affect the wind loads on the principal shell. The most unfavorable wind direction is around 30~, whereas the effects of the wind field and the height of the coal stack are small. The surfaces of the shells are divided into nine blocks, and the block mean and fluctuating (rms) pressure coefficients suitable for engineering applications are given as references for wind load codes.展开更多
A vortex-induced vibration(VIV)experiment on three side-by-side risers subjected to a uniform flow was carried out in a combined wave-current flume.The dynamic features of interference effect on three side-by-side ris...A vortex-induced vibration(VIV)experiment on three side-by-side risers subjected to a uniform flow was carried out in a combined wave-current flume.The dynamic features of interference effect on three side-by-side risers were investigated by varying fluid velocity and inter-riser spacing.The distributions of dimensionless displacement,dominant frequency,and displacement trajectory of the model risers were measured using mode decomposition and wavelet transform techniques.The coupled interference of inter-riser fluid to adjacent risers at different spacings was disclosed by introducing the"interference ratio"concept.The results show that at spacings smaller than 6.0 D,the three model risers display appreciable deviations in their displacement responses in cross-flow or in-line direction,attributable to the strong proximity disturbance and wake interference between the risers.When the spacing is increased to 8.0 D,wake interference still makes great difference to the dynamic response of the risers in both directions.As reduced velocity increases,the three risers show higher agreement with an isolated riser in overall dominant vibration frequency in CF direction than that in IL direction at all spacings and the side risers,although symmetrically placed,do not vibrate symmetrically,as a result of the steady deflection of clearance flow within the riser group.Interference effect results in a remarkable unsteady mode competition within the risers;quantitation of the interference levels for the three risers at different spacings with interference ratio revealed that under low flow velocities and large spacing ratios,clearance flow constitutes a non-neglectable interferer for three side-by-side risers.展开更多
In shale gas mining,the inter-fracture interference effect will significantly occur if the actual well deviates from the planned trajectory.To reduce production loss,operators want to get back on the planned trajector...In shale gas mining,the inter-fracture interference effect will significantly occur if the actual well deviates from the planned trajectory.To reduce production loss,operators want to get back on the planned trajectory economically and safely.Based on this,a multi-objective optimization model of deviationcorrection trajectory is established considering the production loss evaluation.Firstly,the functional relationship between the production envelope and the fracturing depth is constructed,and the production loss is obtained by combining the calculation method of volume flow.Based on the proposed“double-arc”trajectory design method,the production loss of the fracture on the deviation-correction trajectory is obtained.Finally,combined with the well profile energy evaluation,a new optimization model of deviation-correction trajectory is established.The results demonstrate that after optimizing the fracturing depth,the production loss of the deviation-correction trajectory is reduced by 13.2%.The maximum curvature value results in a trajectory with a minimum production loss yet a maximum well profile energy.The proposed model reduces the well profile energy by 15.6%compared with the existing model.It is proved that the proposed model can reduce the probability of drilling accidents and achieve high gas production in the later mining stage.This study fully considers various factors affecting horizontal wells in the fracturing area,which can provide theoretical guidance for the design of deviationcorrection trajectory.展开更多
To explore further the launch mechanism of the new underwater launching technology proposed in this paper, the expansion characteristics of four wall combustion-gas jets in confined liquid space must be studied firstl...To explore further the launch mechanism of the new underwater launching technology proposed in this paper, the expansion characteristics of four wall combustion-gas jets in confined liquid space must be studied firstly. The experimental device is designed, and the high-speed digital photographic system is adopted to obtain the expansion sequence processes of Taylor cavities formed by the four wall jets. Meanwhile, the influence of the injection pressure on the axial expansion property of the four wall jets is discussed. Based on the experiments, a three-dimensional unsteady mathematical model is established to simulate the turbulent flow process of the four wall jets expanding in liquid, and the temporal and spatial distribution laws of phase, pressure, temperature, and velocity and the evolution rules of vortices are illustrated in detail. Results show that, accompanied by the jets expanding downstream, the four wall combustion-gas jets get close to each other and achieve convergence eventually under induction of the interference effect between multiple jets. Meanwhile, the heads of the Taylor cavities separate from the observation chamber wall and offset to the central axis of the observation chamber with time going on. The numerical simulation results of the four wall combustion-gas jets coincide well with the experimental data.展开更多
Fully differential cross sections (FDCS) are calculated within a four-body model for single ionization of helium by C6+ impact at the incident energy of 100 MeV/a.u. (atomic unit). The results are compared with e...Fully differential cross sections (FDCS) are calculated within a four-body model for single ionization of helium by C6+ impact at the incident energy of 100 MeV/a.u. (atomic unit). The results are compared with experimental data and other theoretical predictions. It is shown that our results are in very good agreement with experiment for three small momentum transfers in the scattering plane; however, some significant discrepancies are still present at the largest momentum transfer in both the scattering plane and the perpendicular plane. In actuality, the problem has not been explained by the theory during the last decade. Accordingly, the contributions of different scattering amplitudes to FDCS are analyzed. It is found that for the largest momentum transfer the cross section arising from a destructive interference of the three amplitudes is much smaller than the experimental data. However, the cross section due to the constructive interference of two scattering amplitudes between projectile-ionized electron interaction and projectile-passive electron interaction almost approaches the experimental data.展开更多
We investigate the ellipticity of the high-order harmonic generation from the oriented H_(2)^(+)exposed to a linearly polarized laser field by numerically solving the two-dimensional time-dependent Schrodinger equatio...We investigate the ellipticity of the high-order harmonic generation from the oriented H_(2)^(+)exposed to a linearly polarized laser field by numerically solving the two-dimensional time-dependent Schrodinger equation(2 D TDSE).Numerical simulations show that the harmonic ellipticity is remarkably sensitive to the alignment angle.The harmonic spectrum is highly elliptically polarized at a specific alignment angleθ=30°,which is insensitive to the variation of the laser parameters.The position of the harmonic intensity minima indicates the high ellipticity,which can be attributed to the two-center interference effect.The high ellipticity can be explained by the phase difference of the harmonics.This result facilitates the synthesis of a highly elliptical isolated attosecond pulse with duration down to 65 as,which can be served as a powerful tool to explore the ultrafast dynamics of molecules and study chiral light-matter interaction.展开更多
The ballistic thermoelectric properties in bended graphene nanoribbons(GNRs) are systematically investigated by using atomistic simulation of electron and phonon transport. We find that the electron resonant tunneli...The ballistic thermoelectric properties in bended graphene nanoribbons(GNRs) are systematically investigated by using atomistic simulation of electron and phonon transport. We find that the electron resonant tunneling effect occurs in the metallic–semiconducting linked ZZ-GNRs(the bended GNRs with zigzag edge leads). The electron-wave quantum interference effect occurs in the metallic–metallic linked AA-GNRs(the bended GNRs with armchair edge leads).These different physical mechanisms lead to the large Seebeck coefficient S and high electron conductance in bended ZZGNRs/AA-GNRs. Combined with the reduced lattice thermal conduction, the significant enhancement of the figure of merit ZT is predicted. Moreover, we find that the ZTmax(the maximum peak of ZT) is sensitive to the structural parameters. It can be conveniently tuned by changing the interbend length of bended GNRs. The magnitude of ZT ranges from the 0.15 to 0.72. Geometry-controlled ballistic thermoelectric effect offers an effective way to design thermoelectric devices such as thermocouples based on graphene.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
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 National Natural Science Foundation of China (Grant No 10734140)the National Basic Research Program of China (Grant No 2007CB815105)
文摘Interference effects on the photoionization cross sections between two neighbouring atoms are considered based on the coherent scattering of the ionized electrons by the two nuclei when their separation is less than or comparable to the de Broglie wave length of the ionized electrons. As an example, the single atomic nitrogen ionization cross section and the total cross sections of two nitrogen atoms with coherently added photoionization amplitudes are calculated from the threshold to about А (1 А=0.1 nm) of the photon energy. The photoionization cross sections of atomic nitrogen are obtained by using the close-coupling R-matrix method. In the calculation 19 states are included. The ionization energy of the atomic nitrogen and the photoionization cross sections agree well with the experimental results. Based on the R-matrix results of atomic nitrogen, the interference effects between two neighbouring nitrogen atoms are obtained. It is shown that the interference effects are considerable when electrons are ionized just above the threshold, even for the separations between the two atoms are larger than two times of the bond length of N2 molecules. Therefore, in hot and dense samples, effects caused by the coherent interference between the neighbours are expected to be observable for the total photoionization cross sections.
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The work was supported by the National Natural Science Foundation of China(Grant No.50608030).
文摘The aerodynamic interference effects on aero-static coefficients of twin deck bridges with large span were investigated in detail by means of wind tunnel test.The distances between the twin decks and wind attack angles were changed during the wind tunnel test to study the effects on aerodynamic interferences of aerostatic coefficients of twin decks.The research results have shown that the drag coefficients of the leeward deck are much smaller than that of a single leeward deck.The drag coefficients of a windward deck decrease slightly com-pared with that of a single deck.The lift and torque coefficients of windward and leeward decks are also affected slightly by the aerodynamic interference of twin decks.And the aerodynamic interference effects on lift and torque coefficients of twin decks can be neglected.
基金Supported by the National Natural Science Foundation of China(11847168)the Fundamental Research Funds for the Central Universities of China(GK201803019,GK202003018,1301031995)the Natural Science Foundation of Shannxi Province,China(2019JM-431,2019JQ-739)。
文摘We calculate the spinor helicity amplitudes of anomalous H→ZZ→4ℓdecay.After embedding these analytic formulas into the MCFM package,we study the interference effects between the anomalous gg→H→ZZ→4ℓprocess and the SM processes,which are indispensable in the Higgs off-shell region.Subsequently,the constraints on the anomalous couplings are estimated using LHC experimental data.
基金Supported by National Natural Science Foundation of China(11375021,11447018)New Century Excellent Talents in University(NCET)(NCET-13-0030)+1 种基金Major State Basic Research Development Program of China(2015CB856701)Fundamental Research Funds for Central Universities,Education Ministry of LiaoNing Province
文摘A high luminosity Circular Electron Positron Collider(CEPC) as a Higgs Factory will be helpful for precision measurements of the Higgs mass. The signal-background interference effect is carefully studied for the Higgs diphoton decay mode in associated Z boson production at future e^+e^-colliders at energy 246 GeV. The mass shifts go up from about 20 MeV to 50 MeV for the experimental mass resolution ranging from 0.8 GeV to 2 GeV.
基金supported by the National Natural Science Foundation of China(Grant Nos.51709161 and U2006226)the Key Technology Research and Development Program of Shandong Province(Grant No.2019GHY112061)+1 种基金the Natural Science Foundation of Shandong Province(Grant No.ZR2022QE118)the Youth Talent Introduction and Cultivation Program of College in Shandong Province。
文摘A partition model of interference efficiency was constructed to study the coupling interference effect under combined internal and external flow.The concept of“internal flow efficiency”,“velocity ratio”and“interference efficiency”were introduced to quantify the effect of internal flow and interference,and reveal the coupling mechanism among internal flow,external flow and interference effect.The results showed that the dynamic response of risers under variable angles was significantly different after considering the effect of internal flow.When the external flow velocity was smaller than 0.25 m/s,the vibration of risers was promoted by the internal flow.With the increase of external flow velocity,the effect of internal flow was weakened and the dynamic response of riser mainly depended on the external flow and interference effect.Under the effect of different internal flow,the interference efficiency had similar change trend.The interference effect amplified the complex secondary flow effect inside the riser,making the dynamic response of riser complex and random.In this paper,the overlap area and subdivision criterion of interference effect were constructed within the range of experimental velocity ratio,and the change curve of interference efficiency was obtained with an average meaning,which may have important practical meaning.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.51709161 and U2006226)the Key Technology Research and Development Program of Shandong Province(Grant No.2019GHY112061)+1 种基金the Research and Innovation Team of Ocean Oil and Gas Development Engineering Structure,College of Civil Engineering and Architecture,Shandong University of Science and Technology(Grant No.2019TJKYTD01)the Natural Science Foundation of Shandong Province(Grant No.ZR2020ME261).
文摘The“riser group−fluid between risers”is taken as the carrier,and the experiment on vortex-induced vibration of tandem riser groups coupling interference effect under sensitive spacing is performed.The least-square method is used to linearly fit the reduced velocity and main frequency,and the rule of Strouhal numbers is analyzed.Each mode is separated based on the mode decomposition theory,and the mode conversion mechanism is also explored.The concept of“interference efficiency”is introduced to study the dynamic characteristics and response evolutions of different riser groups.The results show that the wake shielding effect widely exists in tandem riser groups,and the interference effect of midstream and downstream risers on their upstream risers is significantly lower than that of upstream risers on midstream and downstream risers.The trajectories of midstream and downstream risers lag behind their upstream risers due to multiple shadowing effects,the vibration frequency range of downstream riser is widened and the dominant frequency is extremely unstable.Compared with the isolated riser,wake interference suppresses the vibration dis-placement of the midstream and downstream risers in the in-line direction,and enhances the displacement of upstream and midstream risers in the cross-flow direction.The interference effect of the fluid between risers at low velocities is stronger than that at higher velocities,and the cross-flow displacements of upstream risers are always in the interference enhancement region.It is urgent to pay attention to the cross-flow displacement of upstream and midstream risers in tandem riser groups considering the safety design.
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.
基金the National Natural Science Foundation of China(Grant Nos.11474094 and 11104076)the Science and Technology Commission of Shanghai Municipality,China(Grant No.18ZR1412800).
文摘Inspired by a recent experiment[Phys.Rev.Lett.122253201(2019)]that an unprecedented quantum interference was observed in the way of stimulated Raman adiabatic passage(STIRAP)due to the coexisting resonant-and detuned-STIRAPs,we comprehensively study this effect.Our results uncover the scheme robustness towards any external-field fluctuations coming from laser intensity noise and imperfect resonance condition,as well as the persistence of high-contrast interference pattern even when more nearby excited levels are involved.We verify that an auxiliary dynamical phase accumulated in hold time caused by the presence of the quasi-dark state in detuned-STIRAP can sensitively manipulate the visibility and frequency of the interference pattern,representing a new hallmark to measure the hyperfine energy accurately.The robust stability of the scheme comes from the intrinsic superiority embedded in the STIRAP mechanism that preserves the coherence of population transfer,which promises a remarkable performance of quantum interference in a practical implementation.
文摘The phenomena of interference in the course of assembling curved bevel gears are ana. lysed and the corresponding prediction program of interference is established taking KlingInberg bevel gear as an exmple. The factors influencing interferenee are discussed and the coneept ofcritical cutter radius is proposed. Finally, a simplified approximate function between the critical cutter ra- dius and the other factors is derived,and the designing method of avoiding interferenee is provided. The analysis and caiculation are proved to consistent with a case of actual product.
基金Project supported by the Ministry of Science and Technology of China (Nos. SLDRCE09-B-06 and SLDRCE08-A-03)the National Natural Science Foundation of China (Nos. 51178352, 51278368 and 90715040)
文摘The cylindrical reticulated shell structures without side walls, which are normally arranged in pairs, are usually used as dry-coal sheds in a thermal power plant. The wind loads of these shells do not exist in standards or codes. Therefore, this study investigates the mean and fluctuating wind loads on a cylindrical reticulated shell with a rise-to-span ratio of 0.39 through a series of wind tunnel tests. The characteristics of the wind pressures on the upper and lower surfaces and the net pressures are presented. The results show that the wind direction and another shell structure significantly affect the wind loads on the principal shell. The most unfavorable wind direction is around 30~, whereas the effects of the wind field and the height of the coal stack are small. The surfaces of the shells are divided into nine blocks, and the block mean and fluctuating (rms) pressure coefficients suitable for engineering applications are given as references for wind load codes.
基金financially supported by the National Natural Science Foundation of China(Grant No.51709161)Shandong Province Young and Middle-Aged Scientists Research Awards Fund(Grant No.BS2015HZ017)+1 种基金Colleges and Universities of Shandong Province Science and Technology Plan Projects(Grant No.J16LH04)Key R&D Projects in Shandong Province(Grant No.2018GHY115045)。
文摘A vortex-induced vibration(VIV)experiment on three side-by-side risers subjected to a uniform flow was carried out in a combined wave-current flume.The dynamic features of interference effect on three side-by-side risers were investigated by varying fluid velocity and inter-riser spacing.The distributions of dimensionless displacement,dominant frequency,and displacement trajectory of the model risers were measured using mode decomposition and wavelet transform techniques.The coupled interference of inter-riser fluid to adjacent risers at different spacings was disclosed by introducing the"interference ratio"concept.The results show that at spacings smaller than 6.0 D,the three model risers display appreciable deviations in their displacement responses in cross-flow or in-line direction,attributable to the strong proximity disturbance and wake interference between the risers.When the spacing is increased to 8.0 D,wake interference still makes great difference to the dynamic response of the risers in both directions.As reduced velocity increases,the three risers show higher agreement with an isolated riser in overall dominant vibration frequency in CF direction than that in IL direction at all spacings and the side risers,although symmetrically placed,do not vibrate symmetrically,as a result of the steady deflection of clearance flow within the riser group.Interference effect results in a remarkable unsteady mode competition within the risers;quantitation of the interference levels for the three risers at different spacings with interference ratio revealed that under low flow velocities and large spacing ratios,clearance flow constitutes a non-neglectable interferer for three side-by-side risers.
基金financial support from the Natural Science Foundation of China(No.42002307)Fundamental Research Funds for the Central Universities(No.2652019070)National Key Research and Development Program of China(No.2018YFC0603405)
文摘In shale gas mining,the inter-fracture interference effect will significantly occur if the actual well deviates from the planned trajectory.To reduce production loss,operators want to get back on the planned trajectory economically and safely.Based on this,a multi-objective optimization model of deviationcorrection trajectory is established considering the production loss evaluation.Firstly,the functional relationship between the production envelope and the fracturing depth is constructed,and the production loss is obtained by combining the calculation method of volume flow.Based on the proposed“double-arc”trajectory design method,the production loss of the fracture on the deviation-correction trajectory is obtained.Finally,combined with the well profile energy evaluation,a new optimization model of deviation-correction trajectory is established.The results demonstrate that after optimizing the fracturing depth,the production loss of the deviation-correction trajectory is reduced by 13.2%.The maximum curvature value results in a trajectory with a minimum production loss yet a maximum well profile energy.The proposed model reduces the well profile energy by 15.6%compared with the existing model.It is proved that the proposed model can reduce the probability of drilling accidents and achieve high gas production in the later mining stage.This study fully considers various factors affecting horizontal wells in the fracturing area,which can provide theoretical guidance for the design of deviationcorrection trajectory.
基金supported by the National Natural Science Foundation of China (Grant 11372139)
文摘To explore further the launch mechanism of the new underwater launching technology proposed in this paper, the expansion characteristics of four wall combustion-gas jets in confined liquid space must be studied firstly. The experimental device is designed, and the high-speed digital photographic system is adopted to obtain the expansion sequence processes of Taylor cavities formed by the four wall jets. Meanwhile, the influence of the injection pressure on the axial expansion property of the four wall jets is discussed. Based on the experiments, a three-dimensional unsteady mathematical model is established to simulate the turbulent flow process of the four wall jets expanding in liquid, and the temporal and spatial distribution laws of phase, pressure, temperature, and velocity and the evolution rules of vortices are illustrated in detail. Results show that, accompanied by the jets expanding downstream, the four wall combustion-gas jets get close to each other and achieve convergence eventually under induction of the interference effect between multiple jets. Meanwhile, the heads of the Taylor cavities separate from the observation chamber wall and offset to the central axis of the observation chamber with time going on. The numerical simulation results of the four wall combustion-gas jets coincide well with the experimental data.
基金supported by the National Natural Science Foundation of China(Grant No.11274215)the Natural Science Foundation of Shanxi Province,China(Grants Nos.20051008 and 2010011009)the Technology Project of Shanxi Provincial Education Department,China(Grant No.20111011)
文摘Fully differential cross sections (FDCS) are calculated within a four-body model for single ionization of helium by C6+ impact at the incident energy of 100 MeV/a.u. (atomic unit). The results are compared with experimental data and other theoretical predictions. It is shown that our results are in very good agreement with experiment for three small momentum transfers in the scattering plane; however, some significant discrepancies are still present at the largest momentum transfer in both the scattering plane and the perpendicular plane. In actuality, the problem has not been explained by the theory during the last decade. Accordingly, the contributions of different scattering amplitudes to FDCS are analyzed. It is found that for the largest momentum transfer the cross section arising from a destructive interference of the three amplitudes is much smaller than the experimental data. However, the cross section due to the constructive interference of two scattering amplitudes between projectile-ionized electron interaction and projectile-passive electron interaction almost approaches the experimental data.
基金supported by the National Natural Science Foundation of China(Grants Nos.12074142 and 11904122)。
文摘We investigate the ellipticity of the high-order harmonic generation from the oriented H_(2)^(+)exposed to a linearly polarized laser field by numerically solving the two-dimensional time-dependent Schrodinger equation(2 D TDSE).Numerical simulations show that the harmonic ellipticity is remarkably sensitive to the alignment angle.The harmonic spectrum is highly elliptically polarized at a specific alignment angleθ=30°,which is insensitive to the variation of the laser parameters.The position of the harmonic intensity minima indicates the high ellipticity,which can be attributed to the two-center interference effect.The high ellipticity can be explained by the phase difference of the harmonics.This result facilitates the synthesis of a highly elliptical isolated attosecond pulse with duration down to 65 as,which can be served as a powerful tool to explore the ultrafast dynamics of molecules and study chiral light-matter interaction.
基金Project supported by the National Natural Science Foundation of China(Grant No.61401153)the Natural Science Foundation of Hunan Province,China(Grant Nos.2015JJ2050 and 14JJ3126)
文摘The ballistic thermoelectric properties in bended graphene nanoribbons(GNRs) are systematically investigated by using atomistic simulation of electron and phonon transport. We find that the electron resonant tunneling effect occurs in the metallic–semiconducting linked ZZ-GNRs(the bended GNRs with zigzag edge leads). The electron-wave quantum interference effect occurs in the metallic–metallic linked AA-GNRs(the bended GNRs with armchair edge leads).These different physical mechanisms lead to the large Seebeck coefficient S and high electron conductance in bended ZZGNRs/AA-GNRs. Combined with the reduced lattice thermal conduction, the significant enhancement of the figure of merit ZT is predicted. Moreover, we find that the ZTmax(the maximum peak of ZT) is sensitive to the structural parameters. It can be conveniently tuned by changing the interbend length of bended GNRs. The magnitude of ZT ranges from the 0.15 to 0.72. Geometry-controlled ballistic thermoelectric effect offers an effective way to design thermoelectric devices such as thermocouples based on graphene.
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.