外商直接投资技术溢出机制研究——基于江苏省制造业面板数据的实证分析

本文利用2000-2007年江苏省制造业的面板数据,对外商直接投资水平溢出效应和垂直溢出效应进行了检验。结果表明,江苏省外商直接投资存在显著的水平溢出效应、后向溢出效应和前向溢出效应,但水平溢出效应较垂直溢出效应更为明显。并且水平溢出效应和前向溢出效应显示为边际递减,而后向溢出效应的影响是持久的。     

NUMERICAL STUDY ON THE FLOW AROUND A CIRCULAR CYLINDER WITH SURFACE SUCTION OR BLOWING USING VORTICITY-VELOCITY METHOD

A vorticity-velocity method was used to study the incompressible viscous fluid flow around a circular cylinder with surface suction or blowing. The resulted high order implicit difference equations were effeciently solved by the modified incomplete LU decomposition conjugate gradient scheme (MILU-CG). The effects of surface suction or blowing ' s position and strength on the vortex structures in the cylinder wake, as well as on the drag and lift forces at Reynoldes number Re = 100 were investigated numerically. The results show that the suction on the shoulder of the cylinder or the blowing on the rear of the cylinder can effeciently suppress the asymmetry of the vortex wake in the transverse direction and greatly reduce the lift force; the suction on the shoulder of the cylinder, when its strength is properly chosen , can reduce the drag force significantly , too.     

速度-涡量法数值求解具有表面吹吸圆柱的绕流问题

用速度-涡量法数值求解了具有表面吹吸圆柱的绕流问题.所得高阶隐式差分方程,采用以修正的不完全LU分解作预处理器的共轭梯度法(MILU-CG),高效解出.研究了雷诺数Re=100时,各种吹吸位置、吹吸强度对圆柱尾流涡旋结构和阻力、升力系数的影响规律.指出,在圆柱肩部的吸气和在圆柱尾部的吹气,可有效地抑制尾流涡旋结构在垂直来流方向上的非对称性,达到减小升力的目的.对在圆柱肩部吸气的情形,合适选择吸气强度,还可有效减小圆柱在来流方向上所受的阻力.