在化纳米管束和最轻的化晶体中,横向压力诱导的相变
Shaogang Hao1, Gang Zhou, Wenhui Duan
1Department of Physics, Tsinghua University, Beijing 100084, People's Republic of China.
Journal of the American Chemical Society
|March 28, 2008
概括
我们模拟了化 (BN) 纳米管在压力下的相位过渡. 反平行极键规则和管曲率是关键,揭示了储能的新BN阶段.
科学领域:
- 材料科学 材料科学 材料科学
- 凝聚物质物理学 凝聚物质物理学
- 纳米技术纳米技术
背景情况:
- 对齐的晶体化 (BN) 纳米管具有独特的特性.
- 了解它们在外部刺激下的行为对于新的应用至关重要.
研究的目的:
- 模拟和研究在横压下BN纳米管捆的相变机制.
- 确定支配这些转变的关键因素,并发现新的BN阶段.
主要方法:
- 对齐的晶体BN纳米管束的计算模拟.
- 在施加横压下分析相变过程.
主要成果:
- 反平行极键规则被认为对相位过渡至关重要.
- 管的曲率显著影响相位过渡行为.
- 观察到一个独特的sp(2) -sp(3) -sp(2) 过渡.
- 发现了新的BN晶相,包括一种具有密度为2.01g/cm的新型多孔板状堆叠形式.
结论:
- 反平行极键规则和管曲率是BN纳米管相位过渡的关键参数.
- 发现的新型多孔BN阶段为高效的储能应用提供了潜力.
相关概念视频
Phase Transitions
Whether solid, liquid, or gas, a substance's state depends on the order and arrangement of its particles (atoms, molecules, or ions). Particles in the solid pack closely together, generally in a pattern. The particles vibrate about their fixed positions but do not move or squeeze past their neighbors. In liquids, although the particles are closely spaced, they are randomly arranged. The position of the particles are not fixed—that is, they are free to move past their neighbors to occupy...
Phase Transitions
A phase transition is the process in which a substance changes from one state of matter to another, like from a solid to a liquid, liquid to gas, or vice versa, at a specific temperature and under given pressure conditions. This change is spontaneous and is affected by alterations in temperature and pressure. These parameters impact the strength of the forces between molecules (intermolecular forces) in the substance.During a phase transition, both the initial and final phases of the substance...
Phase Transitions: Sublimation and Deposition
Some solids can transition directly into the gaseous state, bypassing the liquid state, via a process known as sublimation. At room temperature and standard pressure, a piece of dry ice (solid CO2) sublimes, appearing to gradually disappear without ever forming any liquid. Snow and ice sublimate at temperatures below the melting point of water, a slow process that may be accelerated by winds and the reduced atmospheric pressures at high altitudes. When solid iodine is warmed, the solid sublimes...
Deformations in a Transverse Cross Section
When a material is subjected to uniaxial stress, it elongates or contracts in the direction of the applied force, and also undergoes changes in the perpendicular directions. This behavior is crucial for understanding how materials behave under stress and is governed by mechanical properties such as Poisson's ratio v, which measures the ratio of transverse strain to axial strain.
As the material stretches, it expands or contracts in orthogonal directions to the load. This phenomenon varies...
As the material stretches, it expands or contracts in orthogonal directions to the load. This phenomenon varies...


