在下层地幔阶段的高温电导机制 (Mg,Fe) 1-xOO
1Department of Geological Sciences, University College London, London WC1E 6BT, UK.
Science (New York, N.Y.)
|March 21, 1997
概括
在下层地幔中,的电导率会随温度变化而变化. 在高温下从小极子向大极子导电的转变会影响地球深层内部的模型.
科学领域:
- 地质物理学和矿物物理
- 高压和高温实验研究的实验研究.
背景情况:
- 酸盐是地球下层地幔的一个关键阶段.
- 以前在大气压下进行的研究表明Fe2+-Fe3+跳跃 (小极子) 控制导电性.
研究的目的:
- 在下层地幔条件下 (高压和高温) 调查化的电导率.
- 为了确定在相关地幔温度下占主导地位的电荷传输机制.
- 评估不同Fe3+含量对导电性的影响.
主要方法:
- 实验测量在的电导率.
- 不同的压力,温度和Fe3+含量.
- 基于实验数据的收费运输机制的分析.
主要成果:
- 电导度测量显示了一个温度依赖的电荷传输机制.
- 在较低的温度下,结果与小的极子传导相一致.
- 在更高的温度下 (与地幔相关),显示出一个大型的极子机制.
结论:
- 中的电荷传输机制随着温度的增加,从小极子转变为大极子.
- 这种转变对解释地质物理数据和建模下层地幔的电特性有重大影响.
- 对地幔状况的准确推断需要考虑这种机制转移及其组成依赖性.
更多相关视频
10:52Conducting Elevated Temperature Normal and Combined Pressure-Shear Plate Impact Experiments Via a Breech-end Sabot Heater System
Published on: August 7, 2018
08:55Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
相关概念视频
02:32Bonding in Metals
Metallic bonds are formed between two metal atoms. A simplified model to describe metallic bonding has been developed by Paul Drüde called the “Electron Sea Model”.
02:39Phase Transitions: Melting and Freezing
Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy becomes large enough to partially overcome the forces holding the molecules or ions of the solid in their fixed positions, and the solid begins the process of transitioning to the liquid state or melting. At this point, the temperature of the solid stops rising, despite the continual input of heat, and it remains constant until all of the solid is...
01:14Mechanisms of Heat Transfer I
Just as interesting as the effects of heat transfer on a system are the methods by which the heat transfer occur. Whenever there is a temperature difference, heat transfer occurs. It may occur rapidly, such as through a cooking pan, or slowly, such as through the walls of a picnic ice box. So many processes involve heat transfer that it is hard to imagine a situation where no heat transfer occurs. Yet, every heat transfer takes place by only three methods: conduction, convection, and radiation.
01:24Superconductor
A substance that reaches superconductivity, a state in which magnetic fields cannot penetrate, and there is no electrical resistance, is referred to as a superconductor. In 1911, Heike Kamerlingh Onnes of Leiden University, a Dutch physicist, observed a relation between the temperature and the resistance of the element mercury. The mercury sample was then cooled in liquid helium to study the linear dependence of resistance on temperature. It was observed that, as the temperature decreased, the...
01:31Ferromagnetism
Materials like iron, nickel, and cobalt consist of magnetic domains, within which the magnetic dipoles are arranged parallel to each other. The magnetic dipoles are rigidly aligned in the same direction within a domain by quantum mechanical coupling among the atoms. This coupling is so strong that even thermal agitation at room temperature cannot break it. The result is that each domain has a net dipole moment. However, some materials have weaker coupling, and are ferromagnetic at lower...
01:17Theory of Metallic Conduction
The conduction of free electrons inside a conductor is best described by quantum mechanics. However, a classical model makes predictions close to the results of quantum mechanics. It is called the theory of metallic conduction.
In this theory, Newton's second law of motion is used to determine the acceleration of an electron in the presence of an applied electric field. Then, its velocity is expressed via this acceleration.
An electron moves through the crystal, containing positive ions,...
In this theory, Newton's second law of motion is used to determine the acceleration of an electron in the presence of an applied electric field. Then, its velocity is expressed via this acceleration.
An electron moves through the crystal, containing positive ions,...