The transverse mass distributions of protons produced in Au-Au collisions at 8 A GeV and Pb-Pb collisions at 158 A GeV are calculated by using the Monte Carlo method in the framework of the multisource ideal gas model...The transverse mass distributions of protons produced in Au-Au collisions at 8 A GeV and Pb-Pb collisions at 158 A GeV are calculated by using the Monte Carlo method in the framework of the multisource ideal gas model.It is found that our calculated results are in agreement with the experimental data in nucleusnucleus collisions at high energies.展开更多
Based on an isospin-dependent transport model, the effects of the density- and momentum-dependent potentials are studied by simulating Au on Au collisions at 90, 120, 150 and 400 MeV/nucleon. It is found that the calc...Based on an isospin-dependent transport model, the effects of the density- and momentum-dependent potentials are studied by simulating Au on Au collisions at 90, 120, 150 and 400 MeV/nucleon. It is found that the calculated results overestimate the experimental data on the directed flow and underestimate the data on the elliptic flow for protons. The impact of the density- and momentum-dependent potentials is observed in the mid-rapidity region of the final spectra. At 90 MeV/nucleon, the momentum-dependent potential has a larger impact on the observables than the density-dependent potential, and the elliptic flow has a higher value with the positive effective mass splitting. At 400 MeV/nucleon, however, the opposite is observed. The rapidity dependence of the elliptic flow for protons is sensitive to the symmetry energy. A soft symmetry energy corresponds to a higher value of the proton elliptic flow.展开更多
The threshold energies of radial flow in reactions of ^40 Ca-^40Ca and ^48Ca＋ ^48Ca in central collisions are investigated within an isospin dependent quantum molecular dynamics model by using three different forms o...The threshold energies of radial flow in reactions of ^40 Ca-^40Ca and ^48Ca＋ ^48Ca in central collisions are investigated within an isospin dependent quantum molecular dynamics model by using three different forms of symmetry energy. It is found that the neutron-rich system has smaller threshold energy of radial flow and this quantity depends on the form of symmetry potential. It is indicated that the threshold energy of radial flow can provide a new method to determine the symmetry energy of asymmetric nuclear matter.展开更多
Surface ligands play critical roles in nanosynthesis and thus it is of great importance in expanding the scope of suitable ligands.In this work,we explore phenynyl ligands in modulating the Au-Au interface when growin...Surface ligands play critical roles in nanosynthesis and thus it is of great importance in expanding the scope of suitable ligands.In this work,we explore phenynyl ligands in modulating the Au-Au interface when growing Au domains on Au seeds.A patchy growth mode is observed where the emerging islands are flat-laying with holes and branches.This growth mode is distinctively different from the conventional facet-controlled growth using weak ligands,and the non-wetting island growth using strong ligands.Through manipulating the molecular structure and the packing of the phenynyl ligands on the Au seeds,the overgrown Au domains are continuously tuned,from patches to islands,extending the plasmon absorption peak into the near-infrared spectral range.We believe that the new ligand with intermediate affinity and the unusual growth mode would expand the control in both synthesis and application.展开更多
The ratio of the number of emitted pions from the target side to that from the projectile side at target rapidity within the reaction plane is investigated for the study of the pion dynamics with an isospin-dependent ...The ratio of the number of emitted pions from the target side to that from the projectile side at target rapidity within the reaction plane is investigated for the study of the pion dynamics with an isospin-dependent quantum molecular dynamic model. The results show that high-energy pions are emitted preferentially towards the target side and, therefore, they are freezed out at the early stage of the collision. By contrast, low-energy pions are emitted predominantly in the opposite direction, which means that they are emitted in a later stage. This argument is based on the shadowing effect caused by the interaction of pions with the spectator matter in peripheral collisions at target or projectile rapidities. This phenomenon disappears in the central collision or at midrapidity due to the weaker shadowing effect. The calculated ratios are also compared with the experimental data.展开更多
The elliptic flow v2, for π±, K±, p and p in Au＋Au collisions at center-of-mass energies √sNN=7.7, 11.5, 14.5 and 19.6 GeV, is analyzed using a multiphase transport model. A significant difference in the ...The elliptic flow v2, for π±, K±, p and p in Au＋Au collisions at center-of-mass energies √sNN=7.7, 11.5, 14.5 and 19.6 GeV, is analyzed using a multiphase transport model. A significant difference in the v2 values for p and p is observed, and the values of v2 splitting are larger compared with π＋ and π-, K＋ and K-. The difference increases with decreasing the center-of-mass energy. The effect of the quark coalescence mechanism in a multi-phase transport model to the value of elliptic difference △v2 between p and p- has been discussed. The simulation of Au＋Au collisions at 14.5 GeV shows that the effect of hadron cascade to △v2 is not obvious, and a larger patton-scattering cross section can lead to a larger △v2.展开更多
Taking into account the effects of shadowing and jet quenching, the large transverse momentum distribution of K＋, π＋ and K＋/π＋ ratios at s = 200 GeV originating from resolved photoproduction processes is calcula...Taking into account the effects of shadowing and jet quenching, the large transverse momentum distribution of K＋, π＋ and K＋/π＋ ratios at s = 200 GeV originating from resolved photoproduction processes is calculated based on perturbative quantum chromodynamics. It is found that the contribution of K＋ and π＋ produced by photoproduction processes is evident. The K＋ /π＋ ratios in Au-Au collisions show an obvious enhancement compared with p p collisions. The numerical results indicate that the photoproduetion processes are good modification for kaon and pion production.展开更多
Au@Au@Ag double shell nanoparticles were fabricated and characterized using TEM,STEM-mapping and UV-Vis methods.Using crystal violet as Raman probe,the surface-enhanced Raman scattering(SERS)activity of the as-prepare...Au@Au@Ag double shell nanoparticles were fabricated and characterized using TEM,STEM-mapping and UV-Vis methods.Using crystal violet as Raman probe,the surface-enhanced Raman scattering(SERS)activity of the as-prepared Au@Au@Ag nanoparticles was studied by comparing to Au,Au@Ag and Au@Au core-shell nanoparticles which were prepared by the same methods.Moreover,it can be found that the SERS activity was enhanced obviously by introduction of NaCl and the concentrations of NaCl played a key role in SERS detection.With an appropriate concentration of NaCl,the limit of detection as low as 10^(-10)mol/L crystal violet can be achieved.The possible enhanced mechanism was also discussed.Furthermore,with simple sample pretreatment,the detection limit of 5μg/g Rhodamine B(RhB)in chili powders can be achieved.The results highlight the potential utility of Au@Au@Ag for detection of illegal food additives with low concentrations.展开更多
基金Supported by National Natural Science Foundation of China (10975095, 10675077) Natural Science Foundation of Shanxi Province (2007011005)
文摘The transverse mass distributions of protons produced in Au-Au collisions at 8 A GeV and Pb-Pb collisions at 158 A GeV are calculated by using the Monte Carlo method in the framework of the multisource ideal gas model.It is found that our calculated results are in agreement with the experimental data in nucleusnucleus collisions at high energies.
基金Supported by National Natural Science Foundation of China(11505150)China Postdoctoral Science Foundation(2015M582730)Yuncheng University Research Project(YQ-2014014)
文摘Based on an isospin-dependent transport model, the effects of the density- and momentum-dependent potentials are studied by simulating Au on Au collisions at 90, 120, 150 and 400 MeV/nucleon. It is found that the calculated results overestimate the experimental data on the directed flow and underestimate the data on the elliptic flow for protons. The impact of the density- and momentum-dependent potentials is observed in the mid-rapidity region of the final spectra. At 90 MeV/nucleon, the momentum-dependent potential has a larger impact on the observables than the density-dependent potential, and the elliptic flow has a higher value with the positive effective mass splitting. At 400 MeV/nucleon, however, the opposite is observed. The rapidity dependence of the elliptic flow for protons is sensitive to the symmetry energy. A soft symmetry energy corresponds to a higher value of the proton elliptic flow.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10575012 and 10435020, the Science Foundation of Beljlng, and the Science Foundation of Beijing Normal University.
文摘The threshold energies of radial flow in reactions of ^40 Ca-^40Ca and ^48Ca＋ ^48Ca in central collisions are investigated within an isospin dependent quantum molecular dynamics model by using three different forms of symmetry energy. It is found that the neutron-rich system has smaller threshold energy of radial flow and this quantity depends on the form of symmetry potential. It is indicated that the threshold energy of radial flow can provide a new method to determine the symmetry energy of asymmetric nuclear matter.
基金supported by the National Natural Science Foundation of China(21673117 and 91956109)Jiangsu Provincial Foundation for Specially-Appointed Professor,Jiangsu Science and Technology Plan(BK20211258)+1 种基金Nanjing Tech University(39837102 and 39837140)SICAM Fellowship from Jiangsu National Synergetic Innovation Center for Advanced Materials。
文摘Surface ligands play critical roles in nanosynthesis and thus it is of great importance in expanding the scope of suitable ligands.In this work,we explore phenynyl ligands in modulating the Au-Au interface when growing Au domains on Au seeds.A patchy growth mode is observed where the emerging islands are flat-laying with holes and branches.This growth mode is distinctively different from the conventional facet-controlled growth using weak ligands,and the non-wetting island growth using strong ligands.Through manipulating the molecular structure and the packing of the phenynyl ligands on the Au seeds,the overgrown Au domains are continuously tuned,from patches to islands,extending the plasmon absorption peak into the near-infrared spectral range.We believe that the new ligand with intermediate affinity and the unusual growth mode would expand the control in both synthesis and application.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11421505 and 11220101005the National Basic Research Program of China under Grant No 2014CB845401
文摘The ratio of the number of emitted pions from the target side to that from the projectile side at target rapidity within the reaction plane is investigated for the study of the pion dynamics with an isospin-dependent quantum molecular dynamic model. The results show that high-energy pions are emitted preferentially towards the target side and, therefore, they are freezed out at the early stage of the collision. By contrast, low-energy pions are emitted predominantly in the opposite direction, which means that they are emitted in a later stage. This argument is based on the shadowing effect caused by the interaction of pions with the spectator matter in peripheral collisions at target or projectile rapidities. This phenomenon disappears in the central collision or at midrapidity due to the weaker shadowing effect. The calculated ratios are also compared with the experimental data.
基金Supported by the National Natural Science Foundation of China under Grant No U1332125the Program for Innovation Research of Science in Harbin Institute of Technology under Grant No B201408
文摘The elliptic flow v2, for π±, K±, p and p in Au＋Au collisions at center-of-mass energies √sNN=7.7, 11.5, 14.5 and 19.6 GeV, is analyzed using a multiphase transport model. A significant difference in the v2 values for p and p is observed, and the values of v2 splitting are larger compared with π＋ and π-, K＋ and K-. The difference increases with decreasing the center-of-mass energy. The effect of the quark coalescence mechanism in a multi-phase transport model to the value of elliptic difference △v2 between p and p- has been discussed. The simulation of Au＋Au collisions at 14.5 GeV shows that the effect of hadron cascade to △v2 is not obvious, and a larger patton-scattering cross section can lead to a larger △v2.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11065010 and 11465021
文摘Taking into account the effects of shadowing and jet quenching, the large transverse momentum distribution of K＋, π＋ and K＋/π＋ ratios at s = 200 GeV originating from resolved photoproduction processes is calculated based on perturbative quantum chromodynamics. It is found that the contribution of K＋ and π＋ produced by photoproduction processes is evident. The K＋ /π＋ ratios in Au-Au collisions show an obvious enhancement compared with p p collisions. The numerical results indicate that the photoproduetion processes are good modification for kaon and pion production.
基金supported by the National Natural Science Foundation of China(No.21505118)the Natural Science Foundation of Jiangsu Province of China(BK 20150438)Postdoctoral Research Funding Program of Jiangsu Province of China(No.1701133C).
文摘Au@Au@Ag double shell nanoparticles were fabricated and characterized using TEM,STEM-mapping and UV-Vis methods.Using crystal violet as Raman probe,the surface-enhanced Raman scattering(SERS)activity of the as-prepared Au@Au@Ag nanoparticles was studied by comparing to Au,Au@Ag and Au@Au core-shell nanoparticles which were prepared by the same methods.Moreover,it can be found that the SERS activity was enhanced obviously by introduction of NaCl and the concentrations of NaCl played a key role in SERS detection.With an appropriate concentration of NaCl,the limit of detection as low as 10^(-10)mol/L crystal violet can be achieved.The possible enhanced mechanism was also discussed.Furthermore,with simple sample pretreatment,the detection limit of 5μg/g Rhodamine B(RhB)in chili powders can be achieved.The results highlight the potential utility of Au@Au@Ag for detection of illegal food additives with low concentrations.
