Zentralprojekt

中央项目

• 批准号: 173364713
• 负责人: Professor Dr. Matthias Fuchs
• 金额: --
• 依托单位: Arbeitsgruppe Theorie der weichen Materie
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2010
• 资助国家: 德国
• 起止时间: 2009-12-31 至 2014-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/173364713?language=en
• 关键词: Zentralprojekt

The fundamental understanding of the glass transition constitutes one of the grand challenges in Statistical Physics and Materials Science. It addresses slow cooperative processes in disordered systems where the mechanisms of particle rearrangements and transport are largely unknown. External fields have strong effects, as the time scales of external drive and intrinsic structural rearrangements can easily be made to match. External fields have significant effects on melt properties and the glass transition, and the investigation of the nonlinear response of supercooled liquids to controlled external fields will considerably contribute to our understanding of the complex underlying physics. External manipulations and processing also have an enormous technological impact, e.g., for the final solid properties. Supercooled liquids fall out of equilibrium by themselves upon lowering the temperature, and are also easily driven out of equilibrium by even slow quenches of external fields. Testing the nonlinear response in glassforming systems thus lies at the frontier of studying non-equilibrium and amorphous materials. Our research unit (RU) investigates the combined effects of strong external fields and slow cooperative dynamics in glass-forming systems in order to understand the complex structural, relaxational, and transport phenomena under conditions far from equilibrium. The RU uses strong mechanical and electric fields to obtain insights into the particle motion at the glass transition. Investigated materials range from supercooled alloys, colloidal dispersions, molecular glass formers to ionic fluids, granular media, and disordered media. Experimental techniques include mechanical, dielectric, and conductivity spectroscopy, while theoretical methods include variants of nonequilibrium computer simulations, mode coupling and kinetic theory, potential energy landscape, as well as continuous time random walk analysis. While in the first funding period of the RU common frameworks and approaches were developed for the joint investigations, in the second funding period the heterogeneous dynamics, the resulting length scales of heterogeneous transport, and the transient response under strong applied load or bias will be unifying themes of the continuing collaborations.

对玻璃化转变的基本理解构成了统计物理学和材料科学的重大挑战之一。它解决了无序系统中的缓慢合作过程，其中粒子重排和运输的机制在很大程度上是未知的。外部场有很强的影响，因为外部驱动和内在结构重排的时间尺度可以很容易地匹配。外场对熔体性质和玻璃化转变有着重要的影响，研究过冷液体对受控外场的非线性响应将大大有助于我们理解复杂的基础物理。外部操纵和处理也具有巨大的技术影响，例如，最终的固体性质。过冷液体在降低温度时会自己脱离平衡，并且也容易被外部场的缓慢淬灭驱动而脱离平衡。因此，测试玻璃成形系统的非线性响应是研究非平衡和非晶材料的前沿。我们的研究单位（RU）研究强外场和缓慢的合作动力学在玻璃形成系统的综合影响，以了解复杂的结构，弛豫和运输现象的条件下远离平衡。RU使用强大的机械和电场来深入了解玻璃化转变时的粒子运动。所研究的材料范围从过冷合金、胶体分散体、分子玻璃形成体到离子流体、颗粒介质和无序介质。实验技术包括机械，介电和电导率光谱，而理论方法包括非平衡计算机模拟，模式耦合和动力学理论，势能景观，以及连续时间随机游走分析的变体。在RU的第一个资助期内，为联合调查制定了共同的框架和方法，在第二个资助期内，异质动力学，由此产生的异质传输的长度尺度，以及在强施加负载或偏差下的瞬态响应将成为持续合作的统一主题。