权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Remote sensing of Induced Current in Magnetic Czochralski Crystal Growth

磁直拉晶体生长中感应电流的遥感

基本信息

批准号：
09650012
负责人：
KASUGA Masanobu
金额：
$ 1.98万
依托单位：
Yamanashi 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

(1) Establishment of the Measurement PrincipleBased on Biot-Savart Law and the current induced by the movement of a conducting top in magnetic field, we have calculated the induced secondary magnetic field at arbitrary points outside of the top.(2) Measurement of the Induced FieldUsing solid gallium and liquid gallium as specimen materials, we have measured the induced magnetic field. Solid gallium made a symmetrical large field which is predicted by the theory involving shunt effect. But liquid gallium made a small, nonsymmetrical, complex field. which requires more comprehensive analysis.(3) Measurement of Temperature Rising by the Joule's HeatSince the estimation of the induced current through magnetic field is an inverse problem, we need another way of estimation to assure the uniqueness of the solution. As another approach we measured the surface temperature of the top with time by the infrared thermometer and compared the data with the electric current data. Both data coincide qualitatively. We are continuing more quantitative examination.(4) Development in FutureBy analyzing the saturation and the decrease effect of the induced current density with increasing applied magnetic field, we would understand the suppression mechanism of the flow by the magnetic field. We are also planning to catch the induced current more directly by probing the potential of the surface of rotating top and to calibrate the remote sensing data.

(1)测量原理的建立根据毕奥-萨伐尔定律和导电陀螺在磁场中运动产生的感应电流，计算了陀螺外任意点的感应二次磁场。(2)感生磁场的测量以固体镓和液体镓为样品，测量了感生磁场。固体镓产生了一个对称的大电场，这与分流效应理论相一致。但是液态镓形成了一个小的、不对称的、复杂的场。这需要更全面的分析。(3)焦耳热测量温升由于磁场感应电流的估计是一个反问题，我们需要另一种估计方法来保证解的唯一性。作为另一种方法，我们用红外测温仪测量了顶部的表面温度随时间的变化，并将数据与电流数据进行了比较。这两个数据在性质上是一致的。我们将继续进行更多的定量检查。(4)未来发展通过分析感应电流密度随外加磁场增大而饱和和减小的效应，了解磁场对流动的抑制机理。我们也计划通过探测旋转陀螺表面的电位来更直接地捕捉感应电流，并对遥感数据进行校正。