玻璃的行为:Poisson的比率和液体的脆弱性
Spyros N Yannopoulos1, G P Johari
1Foundation for Research and Technology Hellas, Institute of Chemical Engineering and High Temperature Chemical Processes, PO Box 1414, 26504 Patras, Greece. sny@iceht.forth.gr
Nature
|August 5, 2006
概括
研究人员质疑液体脆弱性 (m) 和弹性模量比 (K∞/G∞) 之间的线性关系. 他们的分析表明这种相关性是有缺陷的,因为更广泛的数据表明眼镜没有这种线性趋势.
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
- 物理化学 物理化学
背景情况:
- 在玻璃物理学中缺乏一个强大的理论,推动了对液体和玻璃参数之间的相关性研究.
- 脆性 (m),即日志性 (粘度) 与Tg/T的斜率,是表征玻璃行为的一个关键参数.
- 诺维科夫和索科洛夫在眼镜中提出了脆弱性 (m) 与瞬间散量和剪切模块 (K∞/G∞) 的比率之间的线性关系.
研究的目的:
- 为了研究液体脆弱性 (m) 与眼镜中的瞬间散量和剪切模块 (K∞/G∞) 的比率之间的拟议的线性关系.
- 批判性地评估诺维科夫和索科洛夫提出的经验相关性.
主要方法:
- 对玻璃性能现有数据和文献的分析.
- 在多种不同的眼镜组中,与弹性模数比率 (K∞/G∞) 的脆弱性参数 (m) 的比较.
主要成果:
- 这项研究挑战了脆弱性 (m) 与弹性模块比率 (K∞/G∞) 之间的普遍线性关系的前提.
- 用更广泛的眼镜重新检查表明",m"与K∞/G∞没有线性相关性.
- 偏好特定的经验变化和在先前的工作中选择性地使用玻璃数据被确定为一个缺陷.
结论:
- 提议的液体脆弱性和弹性模块比率之间的线性相关性并不普遍适用.
- 这些发现表明,玻璃的机械性能和粘性行为之间的关系比以前认为的要复杂得多.
- 需要进一步的研究来全面了解玻璃物理和影响脆弱性的因素.
相关概念视频
01:07Cohesion
Cohesion is the attraction between molecules of the same type, such as water molecules. Water molecules have an overall neutral charge but are polar molecule. An oxygen atom in one water molecule has a partial negative charge that can bind to a hydrogen atom with a partial positive charge in a second water molecule, forming a hydrogen bond. Each water molecule can form up to four hydrogen bonds with other water molecules. Hydrogen bonds are responsible for water's cohesive nature.
On a surface,...
On a surface,...
02:57Surface Tension, Capillary Action, and Viscosity
Surface Tension
The various IMFs between identical molecules of a substance are examples of cohesive forces. The molecules within a liquid are surrounded by other molecules and are attracted equally in all directions by the cohesive forces within the liquid. However, the molecules on the surface of a liquid are attracted only by about one-half as many molecules. Because of the unbalanced molecular attractions on the surface molecules, liquids contract to form a shape that minimizes the number...
The various IMFs between identical molecules of a substance are examples of cohesive forces. The molecules within a liquid are surrounded by other molecules and are attracted equally in all directions by the cohesive forces within the liquid. However, the molecules on the surface of a liquid are attracted only by about one-half as many molecules. Because of the unbalanced molecular attractions on the surface molecules, liquids contract to form a shape that minimizes the number...
01:09Poisson Probability Distribution
A Poisson probability distribution is a discrete probability distribution. It gives the probability of a number of events occurring in a fixed interval of time or space if these events happen at a known average rate and independently of the time since the last event. For example, a book editor might be interested in the number of words spelled incorrectly in a particular book. It might be that, on average, there are five words spelled incorrectly in 100 pages. The interval is 100 pages.
The...
The...
01:20Characteristics of Fluids
When a force is applied parallel to the top surface of a solid, it resists the applied force due to the internal frictional forces between the layers of the solid known as shearing resistance. However, when the force is removed, the shearing forces restore the original shape of the solid. Other deformation forces also cause temporary changes in shape if the forces are not beyond a threshold magnitude. Solids tend to retain their shape, making the study of their rest and motion easier. Beyond...
01:23Poisson's Ratio
Poisson's ratio is a material property that indicates their stress response. It explains the connection between the elongation or compression a material undergoes in the direction of an applied force and the contraction or expansion it experiences perpendicular to that force. When a slender bar is loaded axially, it stretches in the direction of the force and contracts laterally. Poisson's ratio is the negative ratio of this lateral contraction to the axial elongation. The negative sign ensures...
01:31Characteristics of Fluids
Fluids differ from solids primarily in their molecular structure and stress response. Solids have tightly packed molecules with strong intermolecular forces, maintaining their shape and resisting deformation. In contrast, fluids have molecules spaced farther apart with weaker forces, allowing them to flow and deform easily.
Fluids, which include both liquids and gases, are substances that deform continuously under shearing stress. For example, water and oil are liquids with molecules that can...
Fluids, which include both liquids and gases, are substances that deform continuously under shearing stress. For example, water and oil are liquids with molecules that can...