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首页> 外文期刊>Proceedings of the National Academy of Sciences of the United States of America >THE OLD PROBLEMS OF GLASS AND THE GLASS TRANSITION, AND THE MANY NEW TWISTS
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THE OLD PROBLEMS OF GLASS AND THE GLASS TRANSITION, AND THE MANY NEW TWISTS

机译：玻璃的老问题和玻璃的转变，以及许多新的扭曲

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In this paper I review the ways in which the glassy state is obtained both in nature and in materials science and highlight a ''new twist''-the recent recognition of polymorphism within the glassy state, The formation of glass by continuous cooling (viscous slowdown) is then examined, the strong/fragile liquids classification is reviewed, and a new twist-the possibility that the slowdown is a result of an avoided critical point-is noted, The three canonical characteristics of relaxing liquids are correlated through the fragility. As a further new twist, the conversion of strong liquids to fragile liquids by pressure-induced coordination number increases is demonstrated, It is then shown that, for comparable systems, it is possible to have the same conversion accomplished via a first-order transition within the liquid state during quenching, This occurs in the systems in which ''polyamorphism'' (polymorphism in the glassy state) is observed, and the whole phenomenology is accounted for by Poole's bond-modified van der Waals model, The sudden loss of some liquid degrees of freedom through such weak first-order transitions is then related to the polyamorphic transition between native and denatured hydrated proteins, since the latter are also glass-forming systems-water-plasticized, hydrogen bond-cross-linked chain polymers (and single molecule glass formers), The circle is closed with a final new twist by noting that a short time scale phenomenon much studied by protein physicists-namely, the onset of a sharp change in d [r(2)] /dT ([r(2)] is the Debye-Waller factor)-is general for glass-forming liquids, including computer-simulated strong and fragile ionic liquids, and is closely correlated with the experimental glass transition temperature, The latter thus originates in strong anharmonicity in certain components of the vibrational density of states, which permits the system to access the multiple minima of its configuration space, The connection between the anharmonicity in these modes, vibrational localization, the Kauzmann temperature, and the fragility of the liquid is proposed as the key problem in glass science. [References: 108]
机译：在本文中，我回顾了自然界和材料科学中获得玻璃态的方式，并着重强调了“新的扭曲”-最近对玻璃态中多态性的认识，即通过连续冷却形成玻璃（粘稠）。然后检查），对强/脆弱液体的分类进行了审查，并指出了一种新的扭曲（可能是由于避免了临界点而导致减速的可能性）。松弛液体的三个典型特征通过脆性关联。作为另一种新的扭曲，证明了通过压力引起的配位数的增加，强液体向易碎液体的转化，然后表明，对于可比较的系统，可以通过内部的一阶跃迁完成相同的转化淬火过程中的液态，这发生在观察到“多态性”（玻璃态的多态性）的系统中，整个现象学是由普尔的键修饰范德华模型引起的，其中一些突然消失然后，通过这种弱的一阶跃迁的液体自由度与天然和变性水合蛋白之间的多态过渡有关，因为后者也是玻璃形成系统-水塑化，氢键交联的链状聚合物（和单分子玻璃形成物），通过指出蛋白质生物学家已经研究的短时间尺度现象，即最后一个尖锐的变角现象，圆以最后的新扭曲闭合。 ge in d [r（2）] / dT（[r（2）]是Debye-Waller因子）-是玻璃形成液体（包括计算机模拟的强而易碎的离子液体）的通称，并且与实验玻璃化转变温度，后者因此源自状态振动密度的某些分量中的强非谐性，这使系统能够访问其配置空间的多个极小值。在这些模式下的非谐性之间的联系，振动局部化，Kauzmann温度，液体的脆性被认为是玻璃科学中的关键问题。 [参考：108]

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