采用离散单元法(discrete element method,DEM)和实验方法,研究用螺旋钻具钻取月壤的过程中,月壤内部大颗粒位置和构型对钻进力载特性的影响。通过DEM方法和实验方法研究结果的对比分析,明确了DEM方法在钻取动力学中的局限性及有效性,...采用离散单元法(discrete element method,DEM)和实验方法,研究用螺旋钻具钻取月壤的过程中,月壤内部大颗粒位置和构型对钻进力载特性的影响。通过DEM方法和实验方法研究结果的对比分析,明确了DEM方法在钻取动力学中的局限性及有效性,发现钻进过程中碰到大颗粒时的典型力载特征及影响大颗粒有效拨开的关键因素是表面形态。展开更多
In this paper,the forms of Zn,Cd,Pb and Cu in water from the Changjiang source to the estuary area were determined by ASV method.The main results are as follows:(a) The total contents (Ct)of Zn,Pb,Cu and Cd in the sou...In this paper,the forms of Zn,Cd,Pb and Cu in water from the Changjiang source to the estuary area were determined by ASV method.The main results are as follows:(a) The total contents (Ct)of Zn,Pb,Cu and Cd in the source were 4.0,1. 88,1. 28 and 0. 07μg/L respectively,while Ct were in the ordet of Zn(20.1μg/L)>Cu (14. 9 μg/L) > Pb (6.73 μg/L)>Cd(0.15 μg/L)in mainstream and Zn (93.6μg/L)>Cu (7. 71 μg/L)>Pb(5. 65 μg/L) in the estuary area.However most of them were presented as Mp. Their dissolved contents (Cs)were in lower levels of Zn(1.4 μg/L)>Cu(1.3 μg/L)>Pb(0. 11 μg/L)>Cd (0. 012 μg/L).(b) The distribution of soluble forms is related to the type of metal and to the environmental variables. From source to the mainstream, the major form of Zn from MALi converted into MAb, Cd resembles Zn in forms of distribution,Pb,mainly existed as MAb.Cu,as MLb. But in the estuary area,the major forms of Cd and Pb were all MAb, then MALi varied with salinity of water.展开更多
文摘采用离散单元法(discrete element method,DEM)和实验方法,研究用螺旋钻具钻取月壤的过程中,月壤内部大颗粒位置和构型对钻进力载特性的影响。通过DEM方法和实验方法研究结果的对比分析,明确了DEM方法在钻取动力学中的局限性及有效性,发现钻进过程中碰到大颗粒时的典型力载特征及影响大颗粒有效拨开的关键因素是表面形态。
文摘In this paper,the forms of Zn,Cd,Pb and Cu in water from the Changjiang source to the estuary area were determined by ASV method.The main results are as follows:(a) The total contents (Ct)of Zn,Pb,Cu and Cd in the source were 4.0,1. 88,1. 28 and 0. 07μg/L respectively,while Ct were in the ordet of Zn(20.1μg/L)>Cu (14. 9 μg/L) > Pb (6.73 μg/L)>Cd(0.15 μg/L)in mainstream and Zn (93.6μg/L)>Cu (7. 71 μg/L)>Pb(5. 65 μg/L) in the estuary area.However most of them were presented as Mp. Their dissolved contents (Cs)were in lower levels of Zn(1.4 μg/L)>Cu(1.3 μg/L)>Pb(0. 11 μg/L)>Cd (0. 012 μg/L).(b) The distribution of soluble forms is related to the type of metal and to the environmental variables. From source to the mainstream, the major form of Zn from MALi converted into MAb, Cd resembles Zn in forms of distribution,Pb,mainly existed as MAb.Cu,as MLb. But in the estuary area,the major forms of Cd and Pb were all MAb, then MALi varied with salinity of water.
