This research reports the preparation and characterization of copper nanoparticles modified by didecyl benzene sulfonate (DBS),The Cu nanoparticles' size was determined to be 40nm by transmission electron microsco...This research reports the preparation and characterization of copper nanoparticles modified by didecyl benzene sulfonate (DBS),The Cu nanoparticles' size was determined to be 40nm by transmission electron microscope(TEM).The X-ray photoelectron spectrometry(XPS) results show that there are interactions between the copper nanoparticles and DBS function group.The nonlinear optical properties were studied by the four-wave mixing method.The value of x^(3)/α0 was found to be 6.9×10^-11 esucm.展开更多
Competition among the two-plasmon decay(TPD)of backscattered light of stimulated Raman scattering(SRS),filamentation of the electron-plasma wave(EPW)and forward side SRS is investigated by two-dimensional particlein-c...Competition among the two-plasmon decay(TPD)of backscattered light of stimulated Raman scattering(SRS),filamentation of the electron-plasma wave(EPW)and forward side SRS is investigated by two-dimensional particlein-cell simulations.Our previous work[K.Q.Pan et al.,Nucl.Fusion 58,096035(2018)]showed that in a plasma with the density near 1/10 of the critical density,the backscattered light would excite the TPD,which results in suppression of the backward SRS.However,this work further shows that when the laser intensity is so high(>10^(16)W/cm^(2))that the backward SRS cannot be totally suppressed,filamentation of the EPW and forward side SRS will be excited.Then the TPD of the backscattered light only occurs in the early stage and is suppressed in the latter stage.Electron distribution functions further show that trapped-particle-modulation instability should be responsible for filamentation of the EPW.This research can promote the understanding of hot-electron generation and SRS saturation in inertial confinement fusion experiments.展开更多
The establishment of a possible connection between neutrino emission and gravitational-wave(GW)bursts is important to our understanding of the physical processes that occur when black holes or neutron stars merge.In t...The establishment of a possible connection between neutrino emission and gravitational-wave(GW)bursts is important to our understanding of the physical processes that occur when black holes or neutron stars merge.In the Daya Bay experiment,using the data collected from December 2011 to August 2017,a search was per-formed for electron-antineutrino signals that coincided with detected GW events,including GW150914,GW151012,GW151226,GW170104,GW170608,GW 170814,and GW 170817.We used three time windows of±10,±500,and±1000 s relative to the occurrence of the GW events and a neutrino energy range of 1.8 to 100 MeV to search for correlated neutrino candidates.The detected electron-antineutrino candidates were consistent with the expected background rates for all the three time windows.Assuming monochromatic spectra,we found upper limits(90%confidence level)of the electron-antineutrino fluence of(1.13-2.44)×10^(11)cm^(-2)at 5 MeV to 8.0×10^(7)cm^(-2)at 100 MeV for the three time w indows.Under the assumption of a Fermi-Dirac spectrum,the upper limits were found to be(5.4-7.0)×10^(9)cm^(2)for the three time windows.展开更多
The society structure plays an important role in shaping the attitudes,beliefs and public opinion.For studying the role of the society structure in opinion dynamics,we analyze the Sznajd model on small-world network f...The society structure plays an important role in shaping the attitudes,beliefs and public opinion.For studying the role of the society structure in opinion dynamics,we analyze the Sznajd model on small-world network formed by adding shortcuts in a lattice consisting of N nodes arranged in a ring and on two-dimensional(2-D)regular lattice.Through computer simulation,we find that there exists a pseudo-phase transition from the coexistence state forφ<φ_(c) to the consensus state forφ>φ_(c),whereφ_(c) is some threshold for the shortcut densityφ,which is dependent of the complex network topology and the dimensionality of complex networks.Our observations indicate the dependence of the opinion dynamics on the complex system topology.展开更多
Laser interaction with an ultra-thin pre-structured target is investigated with the help of both two-dimensional and threedimensional particle-in-cell simulations.With the existence of aperiodic structure on the targe...Laser interaction with an ultra-thin pre-structured target is investigated with the help of both two-dimensional and threedimensional particle-in-cell simulations.With the existence of aperiodic structure on the target surface,the laser seems to penetrate through the target at its fundamental frequency even if the plasma density of the target is much higher than the laser’s relativistically critical density.The particle-in-cell simulations show that the transmitted laser energy behind the pre-structured target is increased by about two orders of magnitude compared to that behind the flat target.Theoretical analyses show that the transmitted energy behind the pre-structured target is actually re-emitted by electron’islands’ formed by the surface plasma waves on the target surfaces.In other words,the radiation with the fundamental frequency is actually’surface emission,on the target rear surface.Besides the intensity of the component with the fundamental frequency,the intensity of the high-order harmonics behind the pre-structured target is also much enhanced compared to that behind the flat target.The enhancement of the high-order harmonics is also related to the surface plasma waves generated on the target surfaces.展开更多
The prediction of reactor antineutrino spectra will play a crucial role as reactor experiments enter the precision era.The positron energy spectrum of 3.5 million antineutrino inverse beta decay reactions observed by ...The prediction of reactor antineutrino spectra will play a crucial role as reactor experiments enter the precision era.The positron energy spectrum of 3.5 million antineutrino inverse beta decay reactions observed by the Daya Bay experiment,in combination with the fission rates of fissile isotopes in the reactor,is used to extract the positron energy spectra resulting from the fission of specific isotopes.This information can be used to produce a precise,data-based prediction of the antineutrino energy spectrum in other reactor antineutrino experiments with different fission fractions than Daya Bay.The positron energy spectra are unfolded to obtain the antineutrino energy spectra by removing the contribution from detector response with the Wiener-SVD unfolding method.Consistent results are obtained with other unfolding methods.A technique to construct a data-based prediction of the reactor antineutrino energy spectrum is proposed and investigated.Given the reactor fission fractions,the technique can predict the energy spectrum to a 2%precision.In addition,we illustrate how to perform a rigorous comparison between the unfolded antineutrino spectrum and a theoretical model prediction that avoids the input model bias of the unfolding method.展开更多
The paper presents an explicit matrix algorithm to solve the problem of an elastic wedge with three loaded surfaces.The algorithm makes use of a recently published concept of transformation matrix,by which the origina...The paper presents an explicit matrix algorithm to solve the problem of an elastic wedge with three loaded surfaces.The algorithm makes use of a recently published concept of transformation matrix,by which the original surface loads are converted to equivalent loads in half-space.The three loaded edges are considered simultaneously.The developed algorithm is used to study the effects of two free edges of a steel block and tapered rollers with different contact angles.The two load-free edges can substantially increase deformation if the two edges are close in distance.The results of the tapered roller simulation show that deformation is considerably sensitive to the contact angle of the tapered roller.The largest deformation appears at the big end of the roller.Furthermore,empirical formulae for correction factors for the calculation of block or quarter-space deformation based on half-space solutions are summarized.展开更多
In this paper, we investigate by numerical simulations the Bak-Sneppenmodel (BSM) for biological evolution on scale-free networks (SFNs) with various degree exponents γ. We find that the punctuated equilibrium is rat...In this paper, we investigate by numerical simulations the Bak-Sneppenmodel (BSM) for biological evolution on scale-free networks (SFNs) with various degree exponents γ. We find that the punctuated equilibrium is rather robust with respect to the network topology. Furthermore, we analyze the evolution of the criticalaverage fitness h fi ∗ and the exponent τ of h fi 0 avalanche as a function of α (i.e., the degree exponent γ). Our observations indicate the dependence of evolutionary dynamicsof BSM on the complex biosystem topology.展开更多
Many realistic social networks share some universal characteristic properties,such as the small-world effects and the heterogeneous distribution of connectivity degree,which affect the dynamics in society system,espec...Many realistic social networks share some universal characteristic properties,such as the small-world effects and the heterogeneous distribution of connectivity degree,which affect the dynamics in society system,especially the opinion dynamics in society.To see this,we study the opinion dynamics of the Improved Deffuant Model(IDM)in complex networks.When the two opinions differ by less than the confidence parameterǫ(0<ǫ<1),each opinion moves partly in the direction of the other with the convergence parameterµ,which is a function of the opposite’s degree k;otherwise,the two refuse to discuss and no opinion is changed.We analyze the evolution of the steady opinion s∗as a function of the confidence parameterǫ,the relation between the minority steady opinion smin∗and the individual connectivity k,and find some interesting results that show the dependence of the opinion dynamics on the confidence parameter and on the system topology.This study provides a new perspective and tools to understand the effects of complex system topology on opinion dynamics.展开更多
文摘This research reports the preparation and characterization of copper nanoparticles modified by didecyl benzene sulfonate (DBS),The Cu nanoparticles' size was determined to be 40nm by transmission electron microscope(TEM).The X-ray photoelectron spectrometry(XPS) results show that there are interactions between the copper nanoparticles and DBS function group.The nonlinear optical properties were studied by the four-wave mixing method.The value of x^(3)/α0 was found to be 6.9×10^-11 esucm.
基金supported by the National Natural Science Foundation of China(Nos.12205274,12275251,12035002,11975215)
文摘Competition among the two-plasmon decay(TPD)of backscattered light of stimulated Raman scattering(SRS),filamentation of the electron-plasma wave(EPW)and forward side SRS is investigated by two-dimensional particlein-cell simulations.Our previous work[K.Q.Pan et al.,Nucl.Fusion 58,096035(2018)]showed that in a plasma with the density near 1/10 of the critical density,the backscattered light would excite the TPD,which results in suppression of the backward SRS.However,this work further shows that when the laser intensity is so high(>10^(16)W/cm^(2))that the backward SRS cannot be totally suppressed,filamentation of the EPW and forward side SRS will be excited.Then the TPD of the backscattered light only occurs in the early stage and is suppressed in the latter stage.Electron distribution functions further show that trapped-particle-modulation instability should be responsible for filamentation of the EPW.This research can promote the understanding of hot-electron generation and SRS saturation in inertial confinement fusion experiments.
基金Daya Bay is supported in part by the Ministry of Science and Technology o f China, the U.S. Department o f Energy, the Chinese Academy of Sciences, the CASCenter for Excellence in Particle Physics, the National Natural Science Foundation of China, the Guangdong provincial government, the Shenzhen municipal government,the China General Nuclear Power Group, Key Laboratory of Particle and Radiation Imaging (Tsinghua University), the Ministry of Education, Key Laboratory ofParticle Physics and Particle Irradiation (Shandong University), the Ministry o f Education, Shanghai Laboratory for Particle Physics and Cosmology, the ResearchGrants Council o f the Hong Kong Special Administrative Region of China, the University Development Fund of the University of Hong Kong, the MOE program forResearch of Excellence at National Taiwan University, National Chiao-Tung University, NSC fund support from Taiwan, the U.S. National Science Foundation, the AlfredP. Sloan Foundation, the Ministry o f Education, Youth, and Sports of the Czech Republic, the Charles University GAUK (284317), the Joint Institute o f NuclearResearch in Dubna, Russia, the National Commission of Scientific and Technological Research of Chile, and the Tsinghua University Initiative Scientific Research Program.
文摘The establishment of a possible connection between neutrino emission and gravitational-wave(GW)bursts is important to our understanding of the physical processes that occur when black holes or neutron stars merge.In the Daya Bay experiment,using the data collected from December 2011 to August 2017,a search was per-formed for electron-antineutrino signals that coincided with detected GW events,including GW150914,GW151012,GW151226,GW170104,GW170608,GW 170814,and GW 170817.We used three time windows of±10,±500,and±1000 s relative to the occurrence of the GW events and a neutrino energy range of 1.8 to 100 MeV to search for correlated neutrino candidates.The detected electron-antineutrino candidates were consistent with the expected background rates for all the three time windows.Assuming monochromatic spectra,we found upper limits(90%confidence level)of the electron-antineutrino fluence of(1.13-2.44)×10^(11)cm^(-2)at 5 MeV to 8.0×10^(7)cm^(-2)at 100 MeV for the three time w indows.Under the assumption of a Fermi-Dirac spectrum,the upper limits were found to be(5.4-7.0)×10^(9)cm^(2)for the three time windows.
基金This work was Supported by the NSFC(10635020)the Programme of Introducing Talents of Discipline to Universities under Grant No.B08033+1 种基金the State Key Development Program of Basic Research of China(2008CB317106)the Key Project of Chinese Ministry of Education(306022 and IRT0624).
文摘The society structure plays an important role in shaping the attitudes,beliefs and public opinion.For studying the role of the society structure in opinion dynamics,we analyze the Sznajd model on small-world network formed by adding shortcuts in a lattice consisting of N nodes arranged in a ring and on two-dimensional(2-D)regular lattice.Through computer simulation,we find that there exists a pseudo-phase transition from the coexistence state forφ<φ_(c) to the consensus state forφ>φ_(c),whereφ_(c) is some threshold for the shortcut densityφ,which is dependent of the complex network topology and the dimensionality of complex networks.Our observations indicate the dependence of the opinion dynamics on the complex system topology.
基金supported by the Science Challenge Project(No.TZ2016005)China Postdoctoral Science Foundation(No.2017M620430)+1 种基金National Natural Science Foundation of China(Nos.11435011,11575035,11705180,and 11875241)the National Basic Research Program of China(No.2013CB834101)
文摘Laser interaction with an ultra-thin pre-structured target is investigated with the help of both two-dimensional and threedimensional particle-in-cell simulations.With the existence of aperiodic structure on the target surface,the laser seems to penetrate through the target at its fundamental frequency even if the plasma density of the target is much higher than the laser’s relativistically critical density.The particle-in-cell simulations show that the transmitted laser energy behind the pre-structured target is increased by about two orders of magnitude compared to that behind the flat target.Theoretical analyses show that the transmitted energy behind the pre-structured target is actually re-emitted by electron’islands’ formed by the surface plasma waves on the target surfaces.In other words,the radiation with the fundamental frequency is actually’surface emission,on the target rear surface.Besides the intensity of the component with the fundamental frequency,the intensity of the high-order harmonics behind the pre-structured target is also much enhanced compared to that behind the flat target.The enhancement of the high-order harmonics is also related to the surface plasma waves generated on the target surfaces.
基金Supported in part by the Ministry of Science and Technology of Chinathe U.S.Department of Energy,the Chinese Academy of Sciences,the CAS Center for Excellence in Particle Physics,the National Natural Science Foundation of China+3 种基金the Guangdong provincial governmentthe Shenzhen municipal government,the China General Nuclear Power Group,the Research Grants Council of the Hong Kong Special Administrative Region of China,the Ministry of Education in TWthe U.S.National Science Foundation,the Ministry of Education,Youth,and Sports of the Czech Republic,the Charles University Research Centre UNCE,the Joint Institute of Nuclear Research in Dubna,Russiathe National Commission of Scientific and Technological Research of Chile。
文摘The prediction of reactor antineutrino spectra will play a crucial role as reactor experiments enter the precision era.The positron energy spectrum of 3.5 million antineutrino inverse beta decay reactions observed by the Daya Bay experiment,in combination with the fission rates of fissile isotopes in the reactor,is used to extract the positron energy spectra resulting from the fission of specific isotopes.This information can be used to produce a precise,data-based prediction of the antineutrino energy spectrum in other reactor antineutrino experiments with different fission fractions than Daya Bay.The positron energy spectra are unfolded to obtain the antineutrino energy spectra by removing the contribution from detector response with the Wiener-SVD unfolding method.Consistent results are obtained with other unfolding methods.A technique to construct a data-based prediction of the reactor antineutrino energy spectrum is proposed and investigated.Given the reactor fission fractions,the technique can predict the energy spectrum to a 2%precision.In addition,we illustrate how to perform a rigorous comparison between the unfolded antineutrino spectrum and a theoretical model prediction that avoids the input model bias of the unfolding method.
基金the Research Grants Council of Hong Kong(Project No.CityU11213914).
文摘The paper presents an explicit matrix algorithm to solve the problem of an elastic wedge with three loaded surfaces.The algorithm makes use of a recently published concept of transformation matrix,by which the original surface loads are converted to equivalent loads in half-space.The three loaded edges are considered simultaneously.The developed algorithm is used to study the effects of two free edges of a steel block and tapered rollers with different contact angles.The two load-free edges can substantially increase deformation if the two edges are close in distance.The results of the tapered roller simulation show that deformation is considerably sensitive to the contact angle of the tapered roller.The largest deformation appears at the big end of the roller.Furthermore,empirical formulae for correction factors for the calculation of block or quarter-space deformation based on half-space solutions are summarized.
基金L.Guo thanks Prof.W.Li for his valuable suggestions and comments.This work was supported by the NSFC(10635020)the programme of Introducing Talents of Discipline to Universities under Grant No.B08033+1 种基金the State Key Development Program of Basic Research of China(2008CB317103)the Key Project of Chinese Ministry of Education(306022 and IRT0624).
文摘In this paper, we investigate by numerical simulations the Bak-Sneppenmodel (BSM) for biological evolution on scale-free networks (SFNs) with various degree exponents γ. We find that the punctuated equilibrium is rather robust with respect to the network topology. Furthermore, we analyze the evolution of the criticalaverage fitness h fi ∗ and the exponent τ of h fi 0 avalanche as a function of α (i.e., the degree exponent γ). Our observations indicate the dependence of evolutionary dynamicsof BSM on the complex biosystem topology.
基金This work was supported by the National Natural Science Foundation of China under Grants 70571027,10635020by the Ministry of Education in China under Grant 306022.
文摘Many realistic social networks share some universal characteristic properties,such as the small-world effects and the heterogeneous distribution of connectivity degree,which affect the dynamics in society system,especially the opinion dynamics in society.To see this,we study the opinion dynamics of the Improved Deffuant Model(IDM)in complex networks.When the two opinions differ by less than the confidence parameterǫ(0<ǫ<1),each opinion moves partly in the direction of the other with the convergence parameterµ,which is a function of the opposite’s degree k;otherwise,the two refuse to discuss and no opinion is changed.We analyze the evolution of the steady opinion s∗as a function of the confidence parameterǫ,the relation between the minority steady opinion smin∗and the individual connectivity k,and find some interesting results that show the dependence of the opinion dynamics on the confidence parameter and on the system topology.This study provides a new perspective and tools to understand the effects of complex system topology on opinion dynamics.
