The Intermediate Phase in Network Glasses

[00:78361 . thorpe]这位资深而杰出的PI在网络模型的框架内研究玻璃的性质。这种观点侧重于网络连通性等几何细节，通过将模型中最重要的力设为无穷大而将其余力设为零来推导网络。所得到的模型在计算上可以处理大量的粒子。在该模型中，当达到平均配位数的临界值（作为配位数的函数）时（共价玻璃的配位数一般较大，而聚合物玻璃的配位数一般较小），其状态演化为刚性和应力状态。数值结果表明，存在一种刚体无应力的中间状态。这笔拨款支持网络玻璃中间阶段的进一步工作。最近在硫系玻璃中的实验为这种性质的中间相提供了初步证据。这位资深而杰出的PI是涉及眼镜的广泛研究领域的领导者。特别是，他相信玻璃的许多特性可以用一个几何模型来研究，即一个由棒和球组成的模型，他注意到玻璃中存在着可能在实验中看到的奇怪的相。从玻璃对平均配位数（给定原子可能连接的原子数）的依赖来看，有两种相，一种是玻璃配位数小，没有刚性，没有累积应力，而在大配位数下，玻璃是刚性的，有累积应力。在过渡段附近，在配位数临界值附近的一个范围内，存在一个中间相，对应于刚性但无应力的玻璃。他计划研究状态的可观察属性

0078361ThorpeThis senior and distinguished PI works on properties of glasses but in the framework of a network model. In this view, which focuses on the geometric details such as network connectivity, the network is derived by putting the most important forces in the model to be infinite and the rest are set equal to zero. The resulting model is computationally manageable with a large number of particles. In this model, at a critical (as a function of) average coordination number (generally covalent glasses have large coordination number while the polymeric glasses in general have smaller coordination number), the states evolve in to a rigid and stressed state. However the numerical results show the existence if an intermediate state which is rigid but not stressed. This grant supports further work on this intermediate phase of a network glass. Recent experiments in chalcogenide glasses give preliminary evidence for an intermediate phase of this nature.%%%This senior and distinguished PI is a leader in the broad field of study involving glasses. In particular, guided by his belief that many properties of glasses can be studied using a geometric model, i.e. one made from sticks and balls, he has noticed the presence of curious phase of glass which may have been seen experimentally. Looking at glasses from their dependence on an average coordination number (number of atoms that a given atom may be connected to) there are two phases, one where the glass has a small coordination number, no rigidity and no accumulated stress while at large coordination number, the glass is rigid and it has accumulated stress. Near the transition, and a range of coordination number around the critical value, there is an intermediate phase corresponds to a rigid but unstressed glass. He plans to look at the observable properties of state.***