The increase of frame rate,though with the potential in a coded ultrasound system,is generally concomitant with the simultaneous transmission of a number of apertures,and in consequence leads to increased cross-talks ...The increase of frame rate,though with the potential in a coded ultrasound system,is generally concomitant with the simultaneous transmission of a number of apertures,and in consequence leads to increased cross-talks between different apertures.In view of this,a new coding scheme using staggering repetition interval was proposed.The transmitting signals were constructed by repeating the two(or more) modulated codes using staggering repetition interval,and then allocated to and transmitted simultaneously among different apertures.The decoding process was based on the subsection-matched filter under the assistance of different matched filters for different apertures.At last the outputs of subsection-matched filtering were added together.Staggering changed the positions of cross-correlation(CC) peaks from coinciding,which resulted in an effective reduction of CC.Our theoretical analysis and simulations showed that,the coding scheme can be used to reduce cross-talk,and a good cross-talk reduction will be achieved if the staggering delay is kept in an appropriate range.展开更多
The△I = 2 and △I = 4 staggering parameters of transition energies Eγfor normally deformed positive parity ground bands in232 Th and236,238 U nuclei are studied in framework of the symplectic extension of the intera...The△I = 2 and △I = 4 staggering parameters of transition energies Eγfor normally deformed positive parity ground bands in232 Th and236,238 U nuclei are studied in framework of the symplectic extension of the interacting vector boson model. The model parameters are obtained from the fitting procedure between the calculated excitation energies and the corresponding experimental ones. The staggering parameters represent the finite difference approximations to higher order derivatives dnEγ/d Inof the γ-ray transition energies in a△I = 2 and △I = 4 bands, which yielding multipoint formulae. The first order derivative(two-point formula) provides us with information about the dynamical moment of inertia. The staggering oscillation for the fourth order derivative(five-point formula) is about 0.5 Ke V and is even larger than that in superdeformed bands. The quite similarity in dynamical moments of inertia of the isotopes236,238 U up to high spin states indicate that the phenomenon of identical bands is not restricted to superdeformed bands.展开更多
Although a 3rd-order difference formula has often been employed to investigate the odd-even staggering(OES)in experimental cross sections,other formulas can also be very useful.In this work,three formulas,the 2nd,4th,...Although a 3rd-order difference formula has often been employed to investigate the odd-even staggering(OES)in experimental cross sections,other formulas can also be very useful.In this work,three formulas,the 2nd,4th,and 5th-order difference formulas,are proposed for systematic OES studies.These new difference formulas with different orders are applied to extract the OES magnitudes in extensive accurate cross sections measured in different fragmentation and spallation reaction systems over a broad energy range.According to comparisons of these(2nd,4th,and 5th-order)OES magnitudes derived from different reaction systems,they almost do not rely on the projectile-target combinations or the projectile energy.A similar universality was observed for the 3rd-order OES magnitudes obtained from various reaction systems in our previous studies of the 3rd-order OES.The weighted average values of the 2nd,4th,and 5th-order OES magnitudes extracted from different experimental datasets are recommended as the 2nd,4th,and 5th-order OES evaluations,respectively.Finally,comparisons of these(new)2nd,4th,5th,and previous 3rd-order OES evaluations support that these OES evaluations with different orders are consistent and that all the difference formulas with different orders are applicable to OES studies.展开更多
In this work,we have performed Skyrme density functional theory(DFT)calculations of nuclei around^132Sn to study whether the abnormal odd-even staggering(OES)behavior of binding energies around N=82 can be reproduced....In this work,we have performed Skyrme density functional theory(DFT)calculations of nuclei around^132Sn to study whether the abnormal odd-even staggering(OES)behavior of binding energies around N=82 can be reproduced.With the Skyrme forces SLy4 and SkM*,we tested the volume-and surface-type pairing forces and also the intermediate between these two pairing forces,in the Hartree-Fock-Bogoliubov(HFB)approximation with or without the Lipkin-Nogami(LN)approximation or particle number projection after the convergence of HFBLN(PLN).The Universal Nuclear Energy Density Function(UNEDF)parameter sets are also used.The trend of the neutron OES against the neutron number or proton number does not change significantly by tuning the density dependence of the pairing force.Moreover,for the pairing force that is favored more at the nuclear surface,a larger mass OES is obtained,and vice versa.It appears that the combination of volume and surface pairing can give better agreement with the data.In the studies of the OES,a larger ratio of surface to volume pairing might be favored.Additionally,in most cases,the OES given by the HFBLN approximation agrees more closely with the experimental data.We found that both the Skyrme and pairing forces can influence the OES behavior.The mass OES calculated by the UNEDF DFT is explicitly smaller than the experimental one.The UNEDF1 and UNEDF2 forces can reproduce the experimental trend of the abnormal OES around^132Sn.The neutron OES of the tin isotopes given by the SkM*force agrees more closely with the experimental one than that given by the SLy4 force in most cases.Both SLy4 and SkM*DFT have difficulties in reproducing the abnormal OES around^132Sn.Using the PLN method,the systematics of OES are improved for several combinations of Skyrme and pairing forces.展开更多
In our previous studies[Phys.Rev.C 97,044619(2018);Phys.Rev.C 103,044610(2021)],a universal odd-even staggering(OES)has been observed in extensive cross sections of isotopes not far from stability,measured for differe...In our previous studies[Phys.Rev.C 97,044619(2018);Phys.Rev.C 103,044610(2021)],a universal odd-even staggering(OES)has been observed in extensive cross sections of isotopes not far from stability,measured for different fragmentation and spallation reactions.Four OES relations have been proposed on the basis of this OES universality.However,it is still unclear whether this OES universality and OES relations are applicable to many isotopes near the drip-lines.Here,the OES in recent experimental cross sections of very neutron-rich nuclei approaching the drip-line(from ^(76)Ge,^(82)Se+^(9)Be)is quantitatively investigated,to further validate the OES universality and OES relations.The OES magnitudes in these experimental data approaching the neutron drip-line generally agree with those evaluated previously,mainly from experimental data near stability.New OES evaluations de-rived from these experimental data are also recommended for more exotic nuclei near the neutron drip-line,which extends the conclusions of our previous OES studies.In addition,the OES relation calculations are consistent with these experimental data of very neutron-rich nuclides according to their comparisons in this work.Finally,comparisons with additional experimental data(from ^(238)U+^(9)Be)also support that new OES evaluations and OES relation calculations can be applied for exotic nuclei near the neutron drip-line.展开更多
This study presents the systematics of energy staggering for magnetic rotational bands with M1 and E2 transition properties,which are strictly consistent with the features of good candidates of magnetic rotational ban...This study presents the systematics of energy staggering for magnetic rotational bands with M1 and E2 transition properties,which are strictly consistent with the features of good candidates of magnetic rotational bands in the A^80,110,130,and 190 mass regions.The regularities exhibited by these bands with respect to the staggering parameter,which increases with increasing spin,are in agreement with the semiclassical description of shears mechanism.Moreover,the abnormal behaviour in the backbend regions or close to band termination has also been discussed.Taking the magnetic dipole bands with same configuration in three N=58 isotones,i.e.,103Rh,105Ag,and 107In,as examples,the transition from chiral to magnetic rotation with the proton number approaching Z=50 is presented.Moreover,the self-consistent tilted axis and principle axis cranking relativistic mean-field theories are applied to investigate the rotational mechanism in the dipole band of 105Ag.展开更多
AI=2 staggering in superdefonned nuclei has been investigated by a perturbed particle-rotor model, of which all observed features are reproduced in the calculations. It is pointed out that the C4symmetry in Hamiltonia...AI=2 staggering in superdefonned nuclei has been investigated by a perturbed particle-rotor model, of which all observed features are reproduced in the calculations. It is pointed out that the C4symmetry in Hamiltonian is not the only cause of AI=2 staggering. This model can be used to make a fit to the experimental data in odd-A superdeformed nuclei.展开更多
Parallel loops account for the greatest amount of parallelism in numerical programs.Executing nested loops in parallel with low run-time overhead is thus very important for achieving high performance in parallel proce...Parallel loops account for the greatest amount of parallelism in numerical programs.Executing nested loops in parallel with low run-time overhead is thus very important for achieving high performance in parallel processing systems.However,in parallel processing systems with caches or local memories in memory hierarchies,“thrashing problem”may arise when data move back and forth frequently between the caches or local memories in different processors.The techniques associated with parallel compiler to solve the problem are not completely developed.In this paper,we present two restructuring techniques called loop staggering,loop staggering and compacting,with which we can not only eliminate the cache or local memory thrashing phenomena significantly,but also exploit the potential parallelism existing in outer serial loop.Loop staggering benefits the dynamic loop scheduling strategies,whereas loop staggering and compacting is good for static loop scheduling strategies,Our method especially benefits parallel programs,in which a parallel loop is enclosed by a serial loop and array elements are repeatedly used in the different iterations of the parallel loop.展开更多
Traditional manufacturing processes for lightweight curved profiles are often associated with lengthy procedures,high costs,low efficiency,and high energy consumption.In order to solve this problem,a new staggered ext...Traditional manufacturing processes for lightweight curved profiles are often associated with lengthy procedures,high costs,low efficiency,and high energy consumption.In order to solve this problem,a new staggered extrusion(SE)process was used to form the curved profile of AZ31 magnesium alloy in this paper.The study investigates the mapping relationship between the curvature,microstructure,and mechanical properties of the formed profiles by using different eccentricities of the die.Scanning electron microscopy(SEM)and electron backscatter diffraction techniques are employed to examine the effects of different eccentricity values(e)on grain morphology,recrystallization mechanisms,texture,and Schmid factors of the products.The results demonstrate that the staggered extrusion method promotes the deep refinement of grain size in the extruded products,with an average grain size of only 15%of the original billet,reaching 12.28μm.The tensile strength and elongation of the curved profiles after extrusion under the eccentricity value of 10 mm,20 mm and 30 mm are significantly higher than those of the billet,with the tensile strength is increased to 250,270,235 MPa,and the engineering strain elongation increased to 10.5%,12.1%,15.9%.This indicates that staggered extrusion enables curvature control of the profiles while improving their strength.展开更多
This study exploits China's"Pilot Program for the Integration of Science and Technology with Finance"as a quasi-natural experiment to investigate the effect of Sci-Tech Finance on corporate financial res...This study exploits China's"Pilot Program for the Integration of Science and Technology with Finance"as a quasi-natural experiment to investigate the effect of Sci-Tech Finance on corporate financial resilience and its underlying mechanisms.Using panel data of A-share firms listed on the Shanghai and Shenzhen stock exchanges from 2000 to 2024 and using a staggered difference-in-differences(DID)model,we find that corporate financial resilience significantly improved after the Sci-Tech Finance policy,as evidenced by reduced earnings volatility and more sustainable profit growth.Heterogeneity analyses show that the effect is more pronounced during periods of high economic policy uncertainty(EPU)and in regions with less developed traditional banking systems.Mechanism analyses suggest that Sci-Tech Finance strengthens firm financial resilience by alleviating financing constraints,mitigating information asymmetry,optimizing investment efficiency,and promoting green innovation.We provide novel evidence on the role of Sci-Tech Finance in stabilizing firm performance and fostering long-term value creation,thereby contributing to the broad literature on high-quality economic development.展开更多
With the widespread application of Staggered Counter-rotating Rotor(SCR)systems in eVTOL and UAV configurations,a comprehensive understanding of SCR performance under Outof-Ground Effect(OGE)and In-Ground Effect(IGE)c...With the widespread application of Staggered Counter-rotating Rotor(SCR)systems in eVTOL and UAV configurations,a comprehensive understanding of SCR performance under Outof-Ground Effect(OGE)and In-Ground Effect(IGE)conditions is crucial for aircraft design and landing safety.This study experimentally measured the changes in thrust and torque of the upper and lower rotors in an SCR system under varying axial and radial distances.It focuses on the interaction mechanisms between the upper and lower rotors and conducts specific IGE state experiments for certain SCR configurations.The findings reveal that changes in the lower rotor predominantly influence the overall performance of the SCR system,regardless of OGE or IGE conditions.Under OGE conditions,radial distance has a more significant impact than axial distance.Conversely,under IGE conditions,the axial distance plays a critical role in improving SCR system performance.These results provide a broad parameter range to assess SCR system performance variations,offering guidance for the design of new concept rotorcraft configurations and the development of aerodynamic prediction models under IGE conditions.展开更多
The lattice Boltzmann method(LBM)is employed to simulate flow around two staggered cylinders within a confined channel.The numerical model is validated against existing experimental data by comparing drag coefficients...The lattice Boltzmann method(LBM)is employed to simulate flow around two staggered cylinders within a confined channel.The numerical model is validated against existing experimental data by comparing drag coefficients and Strouhal numbers in the single-cylinder configuration.The study systematically investigates the influence of vertical(h)and horizontal(l)spacing between the cylinders,as well as the Reynolds number(Re=0.1–160),on the hydrodynamic forces,streamline patterns,and vortex dynamics.Results indicate that reducing the horizontal spacing l suppresses flow separation behind the upstream cylinder,while either excessively small or large vertical spacing h diminishes separation in the downstream cylinder.The onset of periodic vortex shedding is delayed due to inter-cylinder interactions,with the critical Reynolds number increasing to Rec=71–112,significantly higher than that of a single-cylinder case(Re_(c)≈69).During the vortex shedding regime,the downstream cylinder exhibits a greater lift force fluctuation compared to the upstream cylinder.At Re=160,the root-mean-square lift coefficient(C′_(L))ranges from approximately 0.17 to 0.56 for the downstream cylinder,and from 0.018 to 0.4 for the upstream one.The shedding frequency,characterized by the Strouhal number(St),increases with Reynolds number,reaching St=0.12–0.18 at Re=160.Variations in h and l significantly influence St,with a decrease in l or an increase in h lowering the shedding frequency—this effect is more pronounced in the horizontal direction.展开更多
The growing need for enhanced heat dissipation is compelling the development of more effective heat exchangers.Innovation inspired by nature bionics,four types of leaf-shaped pin fins were proposed and four combinatio...The growing need for enhanced heat dissipation is compelling the development of more effective heat exchangers.Innovation inspired by nature bionics,four types of leaf-shaped pin fins were proposed and four combinations of them were considered.The leaf-shaped design of the cooling pin fin enhances uniformity and synergy,effectively creating an optimized flow path that boosts cooling performance.Eight three-dimensional conjugate heat transfer models in staggered arrangement were developed using ANSYS-Fluent software.Aluminum6061material was used as the heat sinkmaterial and single-phase liquid water flowed through the rectangular channel where the Reynolds(R_(e))number varies from 40 to 100.Using the same boundary conditions as the software simulations,two leaf-shaped channels were printed to validate numerical models.Velocity field and temperature differences of the eight proposed leaf-shaped pin fins configurations were discussed by comparison with cylindrical pin fins.Based on the findings of this study,at a Reynolds number of 80,the Leaf B Staggered Array(LBSA)records a maximum temperature that is 0.72 K lower than that of the cylindrical pin fins arrangement.Additionally,the LBSA exhibits a reduction in the friction factor by approximately 33.3%relative to the circular pin fins array under the same R_(e).This implies that the design of LBSA has been optimized to provide better heat dissipation performance while maintaining lower energy consumption.Furthermore,the LBSA demonstrates the most favorable thermal-hydraulic performance index(TPI),which is 1.18 times higher than that of the circular pin fins arrangement at R_(e)=80.The temperature reduction and friction factor reduction of the lobed channel is more pronounced than that of the conventional cooling channel,highlighting its potential to increase heat transfer efficiency and reduce energy consumption in practical applications.展开更多
Natural biomaterials with staggered structures exhibit remarkable mechanical properties owing to their unique microstructure.The microstructural arrangement can induce size-dependent and viscoelastic responses within ...Natural biomaterials with staggered structures exhibit remarkable mechanical properties owing to their unique microstructure.The microstructural arrangement can induce size-dependent and viscoelastic responses within the material.This study proposes a strain gradient viscoelastic shear-lag model to elucidate the intricate interplay between the strain gradient and viscoelastic effect in staggered shells.Our model clarifies the role of both effects,as experimentally observed,in governing the mechanical properties of these biomaterials.A detailed characterization of the size-dependent responses is conducted through the utilization of a microstructural characterization parameter alongside viscoelastic constitutive models.Then,the effective modulus of the staggered shell is defined and its formula is derived through the Laplace transform.Compared to classical models and even the strain gradient elastic model,the strain gradient viscoelastic model offers calculated moduli that are more consistent with experimental data.Moreover,the strengthening-softening effect of staggered structures is predicted using the strain gradient viscoelastic model and critical energy principle.This study contributes significantly to our understanding of the mechanical behavior of structural materials.Additionally,it provides insights for the design of advanced bionic materials with tailored properties.展开更多
Biological load-bearing materials,like the nacre in shells,have a unique staggered structure that supports their superior mechanical properties.Engineers have been encouraged to imitate it to create load-bearing bio-i...Biological load-bearing materials,like the nacre in shells,have a unique staggered structure that supports their superior mechanical properties.Engineers have been encouraged to imitate it to create load-bearing bio-inspired materials which have excellent properties not present in conventional composites.To create such materials with desirable mechanical properties,the optimum structural parameters combination must be selected.Moreover,the optimal design of bio-inspired composites needs to take into account the trade-offs between various mechanical properties.In this paper,multi-objective optimization models were developed using structural parameters as design variables and mechanical properties as optimization objectives,including stiffness,strength,toughness,and dynamic damping.Using the NSGA-II optimization algorithm,a set of optimal solutions were solved.Additionally,three different structures in natural nacre were introduced in order to utilize the better structure when design bio-inspired materials.The range of optimal solutions that obtained using results from previous research were examined and explained why this collection of optimal solution ranges is better.Also,optimal solutions were compared with the structural features and mechanical properties of real nacre and artificial biomimetic composites to validate our models.Finally,the optimum design strategies can be obtained for nacre-like composites.Our research methodically proposes an optimization method for achieving load-bearing bio-inspired materials with excellent properties and creates a set of optimal solutions from which designers can select the one that best suits their preferences,allowing the fabricated materials to demonstrate preferred performance.展开更多
Using data from the 11th to 14th Five-Year Plan periods(2006-2025),this study applies a Difference-in-Differences(DID)approach to assess the impact of industrial policy withdrawal.Industries that have faced policy wit...Using data from the 11th to 14th Five-Year Plan periods(2006-2025),this study applies a Difference-in-Differences(DID)approach to assess the impact of industrial policy withdrawal.Industries that have faced policy withdrawal for over a decade are categorized as the treatment group,while consistently supported industries form the control group.The analysis examines how withdrawal affects firm total factor productivity(TFP)and investment behavior.The results show that policy withdrawal boosts firm TFP by reducing over-investment and improving the efficiency of R&D spending.This effect is particularly evident in industries with strong,competitive leading firms.Additionally,in regions with lower levels of marketization,timely policy withdrawal plays a key role in curbing over-investment.This study also highlights a dual effect of policy withdrawal:while it fosters corporate social responsibility,it may also encourage financial speculation.These findings suggest that the implementation of industrial policy should provide“timely assistance”over a limited timeframe rather than long-term support to well-established industries.As industries mature,policy support should be gradually reduced or phased out to avoid over-investment and enhance firm efficiency.展开更多
基金Project (Nos.60772147 and 60871060) supported by the National Natural Science Foundation of China
文摘The increase of frame rate,though with the potential in a coded ultrasound system,is generally concomitant with the simultaneous transmission of a number of apertures,and in consequence leads to increased cross-talks between different apertures.In view of this,a new coding scheme using staggering repetition interval was proposed.The transmitting signals were constructed by repeating the two(or more) modulated codes using staggering repetition interval,and then allocated to and transmitted simultaneously among different apertures.The decoding process was based on the subsection-matched filter under the assistance of different matched filters for different apertures.At last the outputs of subsection-matched filtering were added together.Staggering changed the positions of cross-correlation(CC) peaks from coinciding,which resulted in an effective reduction of CC.Our theoretical analysis and simulations showed that,the coding scheme can be used to reduce cross-talk,and a good cross-talk reduction will be achieved if the staggering delay is kept in an appropriate range.
文摘The△I = 2 and △I = 4 staggering parameters of transition energies Eγfor normally deformed positive parity ground bands in232 Th and236,238 U nuclei are studied in framework of the symplectic extension of the interacting vector boson model. The model parameters are obtained from the fitting procedure between the calculated excitation energies and the corresponding experimental ones. The staggering parameters represent the finite difference approximations to higher order derivatives dnEγ/d Inof the γ-ray transition energies in a△I = 2 and △I = 4 bands, which yielding multipoint formulae. The first order derivative(two-point formula) provides us with information about the dynamical moment of inertia. The staggering oscillation for the fourth order derivative(five-point formula) is about 0.5 Ke V and is even larger than that in superdeformed bands. The quite similarity in dynamical moments of inertia of the isotopes236,238 U up to high spin states indicate that the phenomenon of identical bands is not restricted to superdeformed bands.
基金Supported by the National Natural Science Foundation of China(12005314)the SYSU 100 Top Talents Program,and the Major Project of Basic and Applied Basic Research of Guangdong Province,China(2021B0301030006)。
文摘Although a 3rd-order difference formula has often been employed to investigate the odd-even staggering(OES)in experimental cross sections,other formulas can also be very useful.In this work,three formulas,the 2nd,4th,and 5th-order difference formulas,are proposed for systematic OES studies.These new difference formulas with different orders are applied to extract the OES magnitudes in extensive accurate cross sections measured in different fragmentation and spallation reaction systems over a broad energy range.According to comparisons of these(2nd,4th,and 5th-order)OES magnitudes derived from different reaction systems,they almost do not rely on the projectile-target combinations or the projectile energy.A similar universality was observed for the 3rd-order OES magnitudes obtained from various reaction systems in our previous studies of the 3rd-order OES.The weighted average values of the 2nd,4th,and 5th-order OES magnitudes extracted from different experimental datasets are recommended as the 2nd,4th,and 5th-order OES evaluations,respectively.Finally,comparisons of these(new)2nd,4th,5th,and previous 3rd-order OES evaluations support that these OES evaluations with different orders are consistent and that all the difference formulas with different orders are applicable to OES studies.
基金Supported by National Natural Science Foundation of China(U1732138,11505056,11605054,11975209,11790325,11947410,11847315)the Outstanding Young Talent Research Fund of Zhengzhou University(152137002)。
文摘In this work,we have performed Skyrme density functional theory(DFT)calculations of nuclei around^132Sn to study whether the abnormal odd-even staggering(OES)behavior of binding energies around N=82 can be reproduced.With the Skyrme forces SLy4 and SkM*,we tested the volume-and surface-type pairing forces and also the intermediate between these two pairing forces,in the Hartree-Fock-Bogoliubov(HFB)approximation with or without the Lipkin-Nogami(LN)approximation or particle number projection after the convergence of HFBLN(PLN).The Universal Nuclear Energy Density Function(UNEDF)parameter sets are also used.The trend of the neutron OES against the neutron number or proton number does not change significantly by tuning the density dependence of the pairing force.Moreover,for the pairing force that is favored more at the nuclear surface,a larger mass OES is obtained,and vice versa.It appears that the combination of volume and surface pairing can give better agreement with the data.In the studies of the OES,a larger ratio of surface to volume pairing might be favored.Additionally,in most cases,the OES given by the HFBLN approximation agrees more closely with the experimental data.We found that both the Skyrme and pairing forces can influence the OES behavior.The mass OES calculated by the UNEDF DFT is explicitly smaller than the experimental one.The UNEDF1 and UNEDF2 forces can reproduce the experimental trend of the abnormal OES around^132Sn.The neutron OES of the tin isotopes given by the SkM*force agrees more closely with the experimental one than that given by the SLy4 force in most cases.Both SLy4 and SkM*DFT have difficulties in reproducing the abnormal OES around^132Sn.Using the PLN method,the systematics of OES are improved for several combinations of Skyrme and pairing forces.
基金Supported by the National Natural Science Foundation of China(12005314)the SYSU 100 Top Talents Program。
文摘In our previous studies[Phys.Rev.C 97,044619(2018);Phys.Rev.C 103,044610(2021)],a universal odd-even staggering(OES)has been observed in extensive cross sections of isotopes not far from stability,measured for different fragmentation and spallation reactions.Four OES relations have been proposed on the basis of this OES universality.However,it is still unclear whether this OES universality and OES relations are applicable to many isotopes near the drip-lines.Here,the OES in recent experimental cross sections of very neutron-rich nuclei approaching the drip-line(from ^(76)Ge,^(82)Se+^(9)Be)is quantitatively investigated,to further validate the OES universality and OES relations.The OES magnitudes in these experimental data approaching the neutron drip-line generally agree with those evaluated previously,mainly from experimental data near stability.New OES evaluations de-rived from these experimental data are also recommended for more exotic nuclei near the neutron drip-line,which extends the conclusions of our previous OES studies.In addition,the OES relation calculations are consistent with these experimental data of very neutron-rich nuclides according to their comparisons in this work.Finally,comparisons with additional experimental data(from ^(238)U+^(9)Be)also support that new OES evaluations and OES relation calculations can be applied for exotic nuclei near the neutron drip-line.
基金Supported by National Natural Science Foundation of China(11675063,11205068,11847310,11775098)
文摘This study presents the systematics of energy staggering for magnetic rotational bands with M1 and E2 transition properties,which are strictly consistent with the features of good candidates of magnetic rotational bands in the A^80,110,130,and 190 mass regions.The regularities exhibited by these bands with respect to the staggering parameter,which increases with increasing spin,are in agreement with the semiclassical description of shears mechanism.Moreover,the abnormal behaviour in the backbend regions or close to band termination has also been discussed.Taking the magnetic dipole bands with same configuration in three N=58 isotones,i.e.,103Rh,105Ag,and 107In,as examples,the transition from chiral to magnetic rotation with the proton number approaching Z=50 is presented.Moreover,the self-consistent tilted axis and principle axis cranking relativistic mean-field theories are applied to investigate the rotational mechanism in the dipole band of 105Ag.
基金National Natural Science Foundation of ChinaNuclear Industry Science Foundation
文摘AI=2 staggering in superdefonned nuclei has been investigated by a perturbed particle-rotor model, of which all observed features are reproduced in the calculations. It is pointed out that the C4symmetry in Hamiltonian is not the only cause of AI=2 staggering. This model can be used to make a fit to the experimental data in odd-A superdeformed nuclei.
文摘Parallel loops account for the greatest amount of parallelism in numerical programs.Executing nested loops in parallel with low run-time overhead is thus very important for achieving high performance in parallel processing systems.However,in parallel processing systems with caches or local memories in memory hierarchies,“thrashing problem”may arise when data move back and forth frequently between the caches or local memories in different processors.The techniques associated with parallel compiler to solve the problem are not completely developed.In this paper,we present two restructuring techniques called loop staggering,loop staggering and compacting,with which we can not only eliminate the cache or local memory thrashing phenomena significantly,but also exploit the potential parallelism existing in outer serial loop.Loop staggering benefits the dynamic loop scheduling strategies,whereas loop staggering and compacting is good for static loop scheduling strategies,Our method especially benefits parallel programs,in which a parallel loop is enclosed by a serial loop and array elements are repeatedly used in the different iterations of the parallel loop.
基金Project(JQ2022E004)supported by the Natural Science Foundation of Heilongjiang Province,China。
文摘Traditional manufacturing processes for lightweight curved profiles are often associated with lengthy procedures,high costs,low efficiency,and high energy consumption.In order to solve this problem,a new staggered extrusion(SE)process was used to form the curved profile of AZ31 magnesium alloy in this paper.The study investigates the mapping relationship between the curvature,microstructure,and mechanical properties of the formed profiles by using different eccentricities of the die.Scanning electron microscopy(SEM)and electron backscatter diffraction techniques are employed to examine the effects of different eccentricity values(e)on grain morphology,recrystallization mechanisms,texture,and Schmid factors of the products.The results demonstrate that the staggered extrusion method promotes the deep refinement of grain size in the extruded products,with an average grain size of only 15%of the original billet,reaching 12.28μm.The tensile strength and elongation of the curved profiles after extrusion under the eccentricity value of 10 mm,20 mm and 30 mm are significantly higher than those of the billet,with the tensile strength is increased to 250,270,235 MPa,and the engineering strain elongation increased to 10.5%,12.1%,15.9%.This indicates that staggered extrusion enables curvature control of the profiles while improving their strength.
文摘This study exploits China's"Pilot Program for the Integration of Science and Technology with Finance"as a quasi-natural experiment to investigate the effect of Sci-Tech Finance on corporate financial resilience and its underlying mechanisms.Using panel data of A-share firms listed on the Shanghai and Shenzhen stock exchanges from 2000 to 2024 and using a staggered difference-in-differences(DID)model,we find that corporate financial resilience significantly improved after the Sci-Tech Finance policy,as evidenced by reduced earnings volatility and more sustainable profit growth.Heterogeneity analyses show that the effect is more pronounced during periods of high economic policy uncertainty(EPU)and in regions with less developed traditional banking systems.Mechanism analyses suggest that Sci-Tech Finance strengthens firm financial resilience by alleviating financing constraints,mitigating information asymmetry,optimizing investment efficiency,and promoting green innovation.We provide novel evidence on the role of Sci-Tech Finance in stabilizing firm performance and fostering long-term value creation,thereby contributing to the broad literature on high-quality economic development.
基金funded by the National Natural Science Foundation of China(Nos.52202443,52275114)the China Postdoctoral Science Foundation(No.2023M731656)+3 种基金the National Key Laboratory of Helicopter Aeromechanics Foundation,China(No.2023-HA-LB-067-05e)the Natural Science Foundation of Jiangsu Province,China(No.BK20220898)the Jiangsu Funding Program for Excellent Postdoctoral Talent,China(No.JB0202003)the Aeronautical Science Foundation of China(No.20232010052002)。
文摘With the widespread application of Staggered Counter-rotating Rotor(SCR)systems in eVTOL and UAV configurations,a comprehensive understanding of SCR performance under Outof-Ground Effect(OGE)and In-Ground Effect(IGE)conditions is crucial for aircraft design and landing safety.This study experimentally measured the changes in thrust and torque of the upper and lower rotors in an SCR system under varying axial and radial distances.It focuses on the interaction mechanisms between the upper and lower rotors and conducts specific IGE state experiments for certain SCR configurations.The findings reveal that changes in the lower rotor predominantly influence the overall performance of the SCR system,regardless of OGE or IGE conditions.Under OGE conditions,radial distance has a more significant impact than axial distance.Conversely,under IGE conditions,the axial distance plays a critical role in improving SCR system performance.These results provide a broad parameter range to assess SCR system performance variations,offering guidance for the design of new concept rotorcraft configurations and the development of aerodynamic prediction models under IGE conditions.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12372251 and 12132015).
文摘The lattice Boltzmann method(LBM)is employed to simulate flow around two staggered cylinders within a confined channel.The numerical model is validated against existing experimental data by comparing drag coefficients and Strouhal numbers in the single-cylinder configuration.The study systematically investigates the influence of vertical(h)and horizontal(l)spacing between the cylinders,as well as the Reynolds number(Re=0.1–160),on the hydrodynamic forces,streamline patterns,and vortex dynamics.Results indicate that reducing the horizontal spacing l suppresses flow separation behind the upstream cylinder,while either excessively small or large vertical spacing h diminishes separation in the downstream cylinder.The onset of periodic vortex shedding is delayed due to inter-cylinder interactions,with the critical Reynolds number increasing to Rec=71–112,significantly higher than that of a single-cylinder case(Re_(c)≈69).During the vortex shedding regime,the downstream cylinder exhibits a greater lift force fluctuation compared to the upstream cylinder.At Re=160,the root-mean-square lift coefficient(C′_(L))ranges from approximately 0.17 to 0.56 for the downstream cylinder,and from 0.018 to 0.4 for the upstream one.The shedding frequency,characterized by the Strouhal number(St),increases with Reynolds number,reaching St=0.12–0.18 at Re=160.Variations in h and l significantly influence St,with a decrease in l or an increase in h lowering the shedding frequency—this effect is more pronounced in the horizontal direction.
基金supported by the Shandong Provincial Natural Science Foundation,China(Grant ZR2024ME136).
文摘The growing need for enhanced heat dissipation is compelling the development of more effective heat exchangers.Innovation inspired by nature bionics,four types of leaf-shaped pin fins were proposed and four combinations of them were considered.The leaf-shaped design of the cooling pin fin enhances uniformity and synergy,effectively creating an optimized flow path that boosts cooling performance.Eight three-dimensional conjugate heat transfer models in staggered arrangement were developed using ANSYS-Fluent software.Aluminum6061material was used as the heat sinkmaterial and single-phase liquid water flowed through the rectangular channel where the Reynolds(R_(e))number varies from 40 to 100.Using the same boundary conditions as the software simulations,two leaf-shaped channels were printed to validate numerical models.Velocity field and temperature differences of the eight proposed leaf-shaped pin fins configurations were discussed by comparison with cylindrical pin fins.Based on the findings of this study,at a Reynolds number of 80,the Leaf B Staggered Array(LBSA)records a maximum temperature that is 0.72 K lower than that of the cylindrical pin fins arrangement.Additionally,the LBSA exhibits a reduction in the friction factor by approximately 33.3%relative to the circular pin fins array under the same R_(e).This implies that the design of LBSA has been optimized to provide better heat dissipation performance while maintaining lower energy consumption.Furthermore,the LBSA demonstrates the most favorable thermal-hydraulic performance index(TPI),which is 1.18 times higher than that of the circular pin fins arrangement at R_(e)=80.The temperature reduction and friction factor reduction of the lobed channel is more pronounced than that of the conventional cooling channel,highlighting its potential to increase heat transfer efficiency and reduce energy consumption in practical applications.
基金supported by the National Natural Science Foundation of China(with Grant Nos.12432003 and 12032001)the National Science and Technology Major Project(Grant No.J2022-V-0003-0029).
文摘Natural biomaterials with staggered structures exhibit remarkable mechanical properties owing to their unique microstructure.The microstructural arrangement can induce size-dependent and viscoelastic responses within the material.This study proposes a strain gradient viscoelastic shear-lag model to elucidate the intricate interplay between the strain gradient and viscoelastic effect in staggered shells.Our model clarifies the role of both effects,as experimentally observed,in governing the mechanical properties of these biomaterials.A detailed characterization of the size-dependent responses is conducted through the utilization of a microstructural characterization parameter alongside viscoelastic constitutive models.Then,the effective modulus of the staggered shell is defined and its formula is derived through the Laplace transform.Compared to classical models and even the strain gradient elastic model,the strain gradient viscoelastic model offers calculated moduli that are more consistent with experimental data.Moreover,the strengthening-softening effect of staggered structures is predicted using the strain gradient viscoelastic model and critical energy principle.This study contributes significantly to our understanding of the mechanical behavior of structural materials.Additionally,it provides insights for the design of advanced bionic materials with tailored properties.
基金Supported by National Natural Science Foundation of China(Grant Nos.52222505,52321002)Shanghai Municipal Natural Science Foundation o China(Grant No.23ZR1415500)。
文摘Biological load-bearing materials,like the nacre in shells,have a unique staggered structure that supports their superior mechanical properties.Engineers have been encouraged to imitate it to create load-bearing bio-inspired materials which have excellent properties not present in conventional composites.To create such materials with desirable mechanical properties,the optimum structural parameters combination must be selected.Moreover,the optimal design of bio-inspired composites needs to take into account the trade-offs between various mechanical properties.In this paper,multi-objective optimization models were developed using structural parameters as design variables and mechanical properties as optimization objectives,including stiffness,strength,toughness,and dynamic damping.Using the NSGA-II optimization algorithm,a set of optimal solutions were solved.Additionally,three different structures in natural nacre were introduced in order to utilize the better structure when design bio-inspired materials.The range of optimal solutions that obtained using results from previous research were examined and explained why this collection of optimal solution ranges is better.Also,optimal solutions were compared with the structural features and mechanical properties of real nacre and artificial biomimetic composites to validate our models.Finally,the optimum design strategies can be obtained for nacre-like composites.Our research methodically proposes an optimization method for achieving load-bearing bio-inspired materials with excellent properties and creates a set of optimal solutions from which designers can select the one that best suits their preferences,allowing the fabricated materials to demonstrate preferred performance.
基金supported by the Major Project of the Beijing Social Science Fund“Research on Constructing a New Development Pattern and the Coordinated Development of the Beijing-Tianjin-Hebei Region”(20ZDA31).
文摘Using data from the 11th to 14th Five-Year Plan periods(2006-2025),this study applies a Difference-in-Differences(DID)approach to assess the impact of industrial policy withdrawal.Industries that have faced policy withdrawal for over a decade are categorized as the treatment group,while consistently supported industries form the control group.The analysis examines how withdrawal affects firm total factor productivity(TFP)and investment behavior.The results show that policy withdrawal boosts firm TFP by reducing over-investment and improving the efficiency of R&D spending.This effect is particularly evident in industries with strong,competitive leading firms.Additionally,in regions with lower levels of marketization,timely policy withdrawal plays a key role in curbing over-investment.This study also highlights a dual effect of policy withdrawal:while it fosters corporate social responsibility,it may also encourage financial speculation.These findings suggest that the implementation of industrial policy should provide“timely assistance”over a limited timeframe rather than long-term support to well-established industries.As industries mature,policy support should be gradually reduced or phased out to avoid over-investment and enhance firm efficiency.
