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arXiv 0704.1356cond-mat.dis-nncond-mat.mtrl-sci
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七种高粘度玻璃形成体的力学和介电弛豫谱

Mechanical and dielectric relaxation spectra in seven highly viscous glass formers

U. Buchenau

摘要:

公布的介电和剪切数据的六个分子玻璃形成者和一种聚合物的热激活过程的频谱方面进行评估,具有相同的屏障密度的延迟谱的剪切和剪切。的粘度,一个独立的参数的拟合,似乎是相关的高势垒截止时间的介电信号,根据这个关键时间后的放松实体的更新的想法。在可以精确拟合的五种情况下,高势垒截止的温度依赖性遵循推挤模型。在我们的7个例子中,有4个例子中的Johari-Goldstein峰可以用势垒密度的高斯分布来描述,叠加在$α$过程的高频尾部。相同物质的介电和剪切测量发现这些高斯峰的相同的峰位置和宽度,但通常是不同的权重。

英文摘要:

Published dielectric and shear data of six molecular glass formers and one polymer are evaluated in terms of a spectrum of thermally activated processes, with the same barrier density for the retardation spectrum of shear and dielectrics. The viscosity, an independent parameter of the fit, seems to be related to the high-barrier cutoff time of the dielectric signal, in accordance with the idea of a renewal of the relaxing entities after this critical time. In the five cases where one can fit accurately, the temperature dependence of the high-barrier cutoff follows the shoving model. The Johari-Goldstein peaks, seen in four of our seven cases, are describable in terms of gaussians in the barrier density, superimposed on the high-frequency tail of the $α$-process. Dielectric and shear measurements of the same substance find the same peak positions and widths of these gaussians, but in general a different weight.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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