Effects of multi-collisions and surface on elliptic flow

The non-central Au+Au collision at center-of-mass energy √s_NN=200 GeV is simulated using AMPT model. It is found that both the integral and differential elliptic flow behaves differently for partons freezing out at different stages. It is shown that the integral elliptic flow of freeze-out partons decreases with time at the early stage, but increases with time at the late stage. The curve of transverse momentum distribution of elliptic flow of partons is more flatter at the early stage than at the late stage. The effect of surface emitting on elliptic flow is argued to be not neglectable.     

A Non-Zero Hadronic Elliptic Flow with a Vanished Partonic Elliptic Flow in a Coalescence Scenario

The elliptic flow of a hadron is calculated using a quark coalescence model based on the quark phase space distribution produced by a free streaming locally thermalized quark in a two-dimensional transverse plane at initial time. Without assuming the quark＇s elliptic flow, it is shown that the hadron obtains a non-zero elliptic flow in this model. The elliptic flow of the hadron is shown to be sensitive to both space momentum correlation and the hadron＇s internal structure. Quark number scaling is obtained only for some special cases.     

抗钒催化裂化催化剂的研制

在分子筛催化剂中加入复合捕钒组分RXO制成抗钒催化裂化催化剂.实验结果表明该催化剂表现出良好的催化性能,具有明显的抗钒作用.     

Eccentricity Scaling of Elliptic Flow in Relativistic Au+Au Collisions

Elliptic flow for Au＋Au non-central collisions at √SNN = 200 GeV is investigated within a （2＋ 1）-dimensiona＇l hydrodynamic model. The results show that the eccentricity scaling for the collisions is almost perfect. The evolution including the phase transition conforms to the demand of scaling invariance of hydrodynamics of the collision system.     

Effects of Surface Emitting and Cumulative Collisions on Elliptic Flow

The integral and differential elliptic flow of partons is calculated using the multiphase transport model for Au＋Au collisions at centre-of-mass energy √SNN=200 GeV. It is shown that elliptic flow of partons freezing out at early time, which is affected mainly by surface emittance, decreases with time and elliptic flow of partons freezing out at late time, which is dominated by cumulative collisions, increases with time. The elliptic flow of partons freezing out early has a large contribution to the flatting of curve of final differential elliptic flow at large transverse momentum. It is argued that the effect of surface emittance is not neglectable.