Effect of Nuclear Binding Energy to K Factor

We modify the square of virtual photon four-momentum by using nuclear binding energy formula, and calculate the effect of nuclear binding energy to K factor and Compton subprocess and annihilate subprocess in A-A collision Drell-Yan process. The outcome indicates that the effect of nuclear binding energy to K factor is obvious in little x region and it would disappear gradually as x increases.     

Isospin Effect on Nuclear Stopping in Intermediate Energy Heavy Ion Collisions

By using the isospin-dependent quantum molecular dynamics model,we study the dependence of nuclear stopping Qzz/A and R in intermediate energy heavy ion collisions on system size,initial N/Z,isospin symmetry potential and the medium correction of two-body cross sections.We find the effect of the initial N/Z ratio and isospin symmetry potential on stopping is weak.The excitation function of Qzz/A and R depends on the form of medium correction of two-body cross sections,the equation of state of nuclear matter.Our results show that the behaviour of the excitation function of Qzz/A and R can provide clearer information of the isospin dependence of the medium correction of two-body cross sections.     

Mass Transfer： a Deciding Factor for the Multiplicity of an Event in Deep Inelastic Collisions

Intermediate stage of the three and four-pronged events is investigated in the reaction ^208Pb＋^197Au at beam energy 11.67 MeV/u. Multiprong events are analysed numerically using an empirical mass-dependent velocityrauge relation. Using the measured three-dimensional coordinates of correlated tracks, it is possible to determine the quantities such as mass transfer and total kinetic energy loss. These quantities are then used to study the intermediate stage of the reaction. It has been observed that mass transfer and total kinetic energy loss at the first step of the reaction decides the multiplicity of an event at the second stage of the sequential fission process.     

Baryonic Effect on χcJ Suppression in Au＋Au Collisions at RHIC Energies

We predict that χcJ mesons at low transverse momentum in the central rapidity region are almost dissociatedby nucleons and antinucleons in hadronic matter produced in central Au Au collisions at relativistic high-ioncollider (RHIC) energies √^sNN = 130 and 200 GeV. In the calculations the nucleon and antinucleon distributionsin hadronic matter are results of evolution from their freeze-out distributions which well fit the experimentaltransverse momentum spectra of proton and antiproton.     

Isospin Effect of Coulomb Interaction on Nuclear Stopping in Intermediate Energy Heavy Ion Collisions

Nuclei offer an interesting isospin situation where symmetry potential, Coulomb term and isopin dependent nucleon-nucleon collisions are simultaneously present. However, in general, Coulomb potential is not studied in the heavy ion collisions. As we know that the Coulomb potential is an important asymmetry term which can bring important isospin effect into the observable in the intermediate energy heavy ion collisions. Recently extensions by Colonna et al.[1] to finite nuclei show that Coulomb and surface effects reduce instability regions. So in this paper the isospin effects of Coulomb term and symmetry potential on the nuclear stopping at intermediate energy heavy ion collisions are studied by using isospin-dependent quantum molecular dynamics model (IQMD).     

Transverse Flow of Kaons in Heavy—Ion Collisions

The transverse flow of positively charged kaons from heavy-ion collisions at intermediate energy is investigated within the framework of the quantum molecular dynamics model.The calculated results whow that the experimental data are only consistent with those including the kaon mean-field potential from the chiral Lagrangian.This indicates that the transverse flow pattern of kaons is a useful probe of the kaon potential in a nuclear medium.     

A Numerical Analysis to the π and K Coupled—Channel Scalar Form Factor

A numerical analysis to the scalar form factor in the ππ and KK coupled-channel system is made by solving the coupled-channel dispersive integral equations by the iteration method.The solutions are found not to be unique,Physical application to the ππ central production in the pp→ppππ process is discussed based upon the numerical solutions we found.     

Influence of Nuclear Deformation on the Potential Energy Surface in Di—Nuclear Model

Influence of the nuclear deformation on the potential energy surface(PES) in a di-nuclear system is studied in details.It is found that the PES shape changes greatly due to the deformation effect.The top point of the PES could be reduced significantly,which implies that the optimum excitation energy could also be reduced greatly and may enhance the fromation probability of the compound nucleus.The dynamical deformaiton as a function of the reaction time in the reaction process is dramatic.The Z/N ratios of fragments tend to follow that of the compound nucleus during the nucleon exchange process,but to fluctuate.     

Calculation of Kaon Electromagnetic Form Factor in the Framework of Coupled Schwinger—Dyson and Bethe—Salpeter Formulation

The kaon electromagnetic form factor is calculated in the framework of coupled Schwinger-Dyson equation in rainbow approximation and Bethe-Salpeter equation in ladder approximation with the modified flat-bottom potential,which is the combination of the flat-bottom potential with considerations for the infrared and ultraviolet asymptotic behaviours of the effective quark-gluon coupling.All our numerical results give good fit to experimental values and other theoretical results.     

Medium Influence of the Nucleon—Nucleon Cross Section on the Fragmentation

Based on an isospin-dependent quantum molecular dynamics model we studied the influence of a medium correction of an isospin-dependent nucleon-nucleon cross section on the fragmentation at the intermediate energy heavy-ion collisions. We found that the medium correction from an isospin-dependent nucleon-nucleon cross section, at the same time, the momentum-dependent interaction also produces an important role for enhancing the influence of the medium correction on the isospin effect of two-body collisions in the fragmentation process.     

Δ—scaling and Information Entropy in Ultra—Relativistic Nucleus—Nucleus Collisions

The Δ-scaling method has been applied to ultra-relativistic p p,C C and Pb Pb collision data simulated using a high-energy Monte Carlo package,LUCIAE 3.0.The Δ-scaling is found to be valid for some physical variables,such as charged particle multiplicity,strange particle multiplicity and number of binary nucleon-nucleon-nucleon collisions from these simulated nucleus-nucleus collisions over an extended energy ranging from E1ab=20 to 200A GeV.In addition we derive the information entropy from the multiplicity distribution as a function of beam energy for these collisions.     

Centrality Dependence of Flow in High—Energy Nucleus—Nucleus Collisions

Directed flow and elliptic flow of final state particles in high-energy nucleus-nucleus collisions in the EMU01 experiment have been studied.The dependences of directed flow and elliptic flow on incident energy and impact centrality of outgoing particles are presented.The results exhibit strong dependence of flow on centrality and energy.We also suggest a more reliable way to determine the event plane resolution here.     

Coupled—Channel Investigation of Collisions of Protons and Antiprotons with Hydrogen Atoms in the 2p States

The impact parameter method is used to calculate the inelastic scattering cross sections of protons and antiprotons,which raise hydrogen atoms from the 2p states to the n=3 states.The calculation involves the n=1,2,3 states of the target and covers the energy range from 3keV to 2500keV.The study of the influence of the sign of the projectile charge is the main target of this investigation.Therefore,the exchange effects in the case of proton-induced reactions are ignored.The results of the calculations are in reasonable agreement with a previous work.     

Effect of System Mass on Isospin Fractionation in Heavy Ion Collisions at Intermediate Energies

Based on the isospin dependent quantum molecular dynamics model(IQMD) we investigated the dependence of isospin fractionation degree (N/Z)n / (N/Z)Nfrag on the mass of system. The (N/Z)n and (N/Z)Nfrag are the neutron proton ratio of nucleon emission (gas phase) and that of fragment emission (liquid phase) respectively. We found that the isospin fractionation degree is a scnsitive function of system mass. The (N/Z)n/ (N/Z)Nfrag, reduces with increasing the mass of colliding system when neutron proton ratio of colliding system is fixed.     

Effect of cobalt promoter on Co—Mo—K／C catalysts used for mixed alcohol synthesis

The structures of sulfided Co-Mo-K/C catalysts were studied by menas of X-ray diffraction (XRD),laser Raman spectra(LRS),and X-ray absorption fine structure(XAFS).Activities for alcohol synthesis via CO hydrogenation were used to characterize the catalytic performance of these catalysts.On the activeated carbon support,molybdenum is mainly resent as MoS2 species which shrinks with the cobalt loading,While cobalt is mainly present in the form of “Co-Mo-S”phase at the low Co loading and partly in a Co9S8--like structure at higher Co loading.The catalysts exhibit outstanding performance for higher alcohol synthesis due to addition of the promotion of cobalt.The catalysts exhibit outstanding performance for higher alcohol synthesis due to the addition of the promotion of cobalt.The activity for alcohol formation is optimized at a Co/Mo atomic ratio of 0.5.Co species operate as s synergistic system,rather than independently from the MoS2 phase.2001 Elsevier Science B.V.All rights reserved.     

EXAFS Study on Structure of Sulfided K—Co—Mo Catalysts

Mixed alcohol is of great promise as octane improver in automotive fuel,and hopeful to replace the MTBE to reduce the environmental pollution,In this field,alkali-promted molybdenum-based catalysts have been given special interest because of their excellent sulfur-tolerance for synthesis of mixed alcohol from CO H2,It was reported that the coblat is a favorable promoter for enhancing alcohol production,especially for improving the selectivity for C2 alcohol[1-3],moreover,strong interaction between Con and Mo is in favor of mixed alcohol synthesis[4].Recently,we prpared a kind of K-Co-Mo ultrafine particles by sol-gel method and it shows much smaller particle size but higher activty and selectivity toward alcohol formation than the one prepared by conventional method[5],The aim of the present work is to research the micostructures of the Mo and Co species in the K-Co-Mo samples prepared by different method.