从内部状态变量到玻璃成型材料的波动:线性动态热容量,膨胀性和压缩性
1Technische Universität Dresden, Institute of Materials Science, Helmholtzstraße 7, 01069 Dresden, Germany and Eastern Switzerland University of Applied Sciences, Institute for Materials Technology and Plastics Processing, Oberseestrasse 10, 8640 Rapperswil, Switzerland.
The Journal of chemical physics
|May 19, 2025
概括
这项研究通过导出记忆功能来简化玻璃成型材料的复杂理论. 这个框架将宏观性质与微观行为联系起来,有助于理解材料动态.
科学领域:
- 材料科学 材料科学 材料科学
- 热力学是一种热力学.
- 统计力学 统计力学
背景情况:
- 宏观现象学理论描述了玻璃成型材料中的散射效应.
- 现有的理论,如热力学与内部状态变量,解释放松机制,但有复杂的形式主义.
- 这种复杂性阻碍了从宏观行为评估微观特征.
研究的目的:
- 开发一个理论框架,将玻璃成型材料的宏观和微观特征联系起来.
- 通过从普通微分方程中推导内存函数来简化对材料行为的评估.
- 为分析热容量,膨胀性和压缩性等线性动态性质提供统一的方法.
主要方法:
- 用内部状态变量的正常坐标变换从普通微分方程中推导和体积的内存函数.
- 开发一个概括的灵敏度矩阵,表示频率域中的线性动态材料行为.
- 运用波动分散定理,从一般化易感度矩阵中得到Prigogine-Defay比.
主要成果:
- 推导出一个通用的灵敏度矩阵及其对称的时间域转换,与微观可逆性对齐.
- 在和体积放松中放松时间均等分布的假设得到了证实.
- 使用平衡波动和波动-消散定理,成功获得了Prigogine-Defay比率.
结论:
- 该研究提供了一个理论框架,结合了经典的不可逆转和理性的热力学.
- 这一框架有助于评估玻璃成型材料的宏观现象学和微观特征.
- 对各种放松时间分布 (Debye,Kohlrausch等) 的概括敏感性的汇编. 是为实际应用而提供.
相关概念视频
01:22Thermal Expansion
4.3K
The expansion of alcohol in a thermometer is one of many commonly encountered examples of thermal expansion, which is the change in size or volume of a given system as its temperature changes. The most visible example is the expansion of hot air. When air is heated, it expands and becomes less dense than the surrounding air, which then exerts an upward force on the hot air to, for example, make steam and smoke rise, and hot air balloons float. The same behavior happens in all liquids and gases,...
4.3K
01:23Heat Capacities of an Ideal Gas II
2.3K
For a system that undergoes a thermodynamic process at a constant volume condition, the heat absorbed is used only to increase the system's internal energy and not for doing any kind of work. While for a system undergoing a thermodynamic process under a constant pressure condition, the amount of heat absorbed is used not only for increasing the internal energy (as a function of temperature) but also for doing some work. The molar heat capacity is the amount of heat required to increase the...
2.3K
01:25Heat Capacities of an Ideal Gas III
2.1K
The number of independent ways a gas molecule can move along straight line, rotate, and vibrate is called its degrees of freedom. Supposing d represents the number of degrees of freedom of an ideal gas, the molar heat capacity at constant volume of an ideal gas in terms of d is
2.1K
01:24Heat and Free Expansion
1.7K
The work done by a thermodynamic system depends not only on the initial and final states but also on the intermediate states—that is, on the path. Like work, when heat is added to a thermodynamic system, it undergoes a change of state, and the state attained depends on the path from the initial state to the final state. Consider an ideal gas cylinder fitted with a piston. When the cylinder is heated at a constant temperature, the gas molecules absorb energy and expand slowly in a...
1.7K
01:09Thermal Stress
2.4K
If the temperature of an object is changed while it is prevented from expanding or contracting, the object is subjected to stress. The stress is compressive if the object expands in the absence of constraint and tensile if it contracts. This stress resulting from temperature change is known as thermal stress. It can be quite large and can cause damage. To avoid this stress, engineers may design components so they can expand and contract freely. For instance, on highways, gaps are deliberately...
2.4K
01:17Heat Capacity: Problem-Solving
471
The heat capacity of a gas is the amount of heat energy required to raise the temperature of a unit mass of gas by one degree Celsius. It is an important thermodynamic property of gases, and its determination is essential in many industrial and scientific applications. Here are the steps to solve problems related to the heat capacities of gases:
Determine the type of gas: The heat capacity of a gas depends on its molecular structure and the degree of freedom of its molecules. Different types of...
Determine the type of gas: The heat capacity of a gas depends on its molecular structure and the degree of freedom of its molecules. Different types of...
471