Theoretical Study of Friction

摩擦力的理论研究

基本信息

批准号：
09640463
负责人：
MATSUKAWA Hiroshi
金额：
$ 2.05万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

项目摘要

We have studied the frictional phenomena of a 2-dimensional model in the presence of the periodic potential in addition to impurities. This model can be applied also to the magnetic flux lattice in film superconductors. It turned out that impurity can diminishes the static frictional force, there is a kind of quasi long range order in the moving lattice even in the presence of impurities and so on. This order exists in the transverse direction for any magnitude of the velocity and cause the transverse pinning, that is, the direction of motion does not change even though we apply external force in the transverse direction. Typical length scale of the order grows with increasing velocity and cause a peculiar behavior of the kinetic frictional force and the transverse pinning force. The velocity dependence of the latter becomes nonmonotonic, which is caused by the change of the discommensurate structure.CDW nonlinear electric conduction which is the manifestation of the macroscopic quantum tunneling is observed in experiments. Two-probe method was employed in the experiments. In order to observe the tunneling currents by this method both CDW's near the electrode and in the bulk must move by quantum tunneling. We have explained the experiments by considering both vortex ring formation as the tunneling process near the electrode and the kink-antikink pair formation as that in the bulk.We have calculated the flow and the work of two kinds of quantum ratchet model and shown that the flow of these systems is the manifestation of the new quantum mechanical phenomena resulting from the interaction with the heat bath.We have discussed the quantum tunneling of the commensurate CDW and shown that the impurity can assist the tunneling.

除了杂质外，我们还研究了在存在周期性潜力的情况下，我们研究了二维模型的摩擦现象。该模型也可以应用于膜超导体中的磁通晶格。事实证明，杂质可以减少静态摩擦力，即使在存在杂质的情况下，移动晶格也有一种准远程顺序。该顺序存在于任何速度的任何大小的横向方向上，并引起横向固定，即，即使我们在横向方向上施加外力，运动方向也不会改变。该顺序的典型长度尺度随着速度的增加而增长，并引起动力学摩擦力和横钉力的特殊行为。后者的速度依赖性变为非单调性，这是由脱节结构的变化引起的。CDW非线性电导传导是在实验中观察到宏观量子隧穿的表现。实验中采用了两种探针方法。为了通过这种方法观察隧道电流，CDW在电极附近，并且在整体中都必须通过量子隧道移动。我们已经通过将涡度环的形成视为电极附近的隧道过程和扭结 - 安提克克对的形成来解释实验。我们已经计算了两种量子棘轮模型的流动和工作，并表明这些系统的流动是在新量子机械现象中的表现。并表明杂质可以帮助隧道。