城市“精明增长”的数学模型研究

城市"精明增长"是为了管理城市蔓延的恶性增长状态,以建设经济繁荣、社会公平、环境可持续发展的城市为目标。在考虑城市的经济、社会、环境和人口为衡量精明增长的主要指标的情况下,为了研究城市的可持续发展,建立微分方程模型,以实际数据为依据,来研究各指标对城市精明增长的影响和对未来城市可持续发展的调控作用。     

Numerical solutions for the transient flow in the homogenous closed circle reservoirs

There are many fault block fields in China. A fault block field consists of fault pools. The small fault pools can be viewed as the closed circle reservoirs in some case. In order to know the pressure change of the developed formation and provide the formation data for developing the fault block fields reasonably, the transient flow should be researched. In this paper, we use the automatic mesh generation technology and the finite element method to solve the transient flow problem for the well located in the closed circle reservoir, especially for the well located in an arbitrary position in the closed circle reservoir. The pressure diffusion process is visualized and the well-location factor concept is first proposed in this paper. The typical curves of pressure vs time for the well with different well-location factors are presented. By comparing numerical results with the analytical solutions of the well located in the center of the closed circle reservoir, the numerical method is verified.     

基性、超基性岩样中稀土元素和其它微量元素的热中子、超热中子活化分析

与花岗岩相比,基性、超基性岩中稀土元素含量低,而干扰元素含量高。对存在的分析难点进行了讨论。针对此特点,选用了热中子与超热中子活化。研究了干扰谱的修正;铀裂变干扰的修正及(n,p)干扰反应等问题。列出了美国地调局的标样W-2,DNC-1及国际原子能机构的标样Soil-S中30种元素的分析结果。表中数据说明工作结果令人满意。     

ICP-MS混合模式测定植物性农产品中的9种痕量元素

建立了ICP- MS混合模式测定蔬菜、水果、大米等植物性农产品中痕量元素的检测方法.样品经HNO3 + H2O2消解,以74Ge,115In、209Bi作为内标溶液消除基体干扰,动能歧视型碰撞/反应池技术消除质谱干扰的方式测定植物性农产品中As,Hg,Pb,Cd,Cr,Se,Cu,Ni,Zn 9种痕量元素.结果表明:该...