AI 中文总结
该研究针对XPCS测量回波存在的硬件要求高、易致样品退化的问题，提出非周期斐波那契序列的束团模式数据采集方案，并用模型胶体悬浮液验证其性能，提供了$g_2(q, \ au)$的定量解析表达式。
AI 中文摘要
在强度-强度自相关函数[$g_2(q, \ au)$]中观测到的回波，是探测受振荡剪切作用的软黏弹性材料的非仿射变形与屈服行为的有效方法。对大量回波进行高时间分辨率的多散斑X射线光子关联谱（XPCS）测量，会对计算硬件提出严苛要求，还可能导致样品退化。通过采用束团模式数据采集方案可缓解这些问题，该方案将以回波峰值为中心的最高分辨率帧或束团置于合适位置。此外，通过将束团置于非周期斐波那契序列中，可在大幅减少帧数（数量级级降低）的情况下测量长时间跨度内的$g_2(q, \ au)$。采用缓慢弛豫的模型胶体悬浮液验证了这些XPCS采集方案的性能，还提供了用于定量描述完整$g_2(q, \ au)$的解析表达式。
英文摘要
Echoes observed in the intensity-intensity autocorrelation functions [$g_2(q, τ)$] is a powerful method for probing nonaffine deformations and yielding behavior of soft viscoelastic materials subjected to an oscillatory shear. Multispeckle X-ray photon correlation spectroscopy (XPCS) measurements of large number of echoes with high time resolution impose severe constraints in terms of the computational hardware and potential degradation of the sample. These issues are alleviated by implementing a bunch-mode data acquisition scheme in which the highest resolution frames or bunches centered at the echo peaks. In addition, by placing the bunches in an aperiodic Fibonacci sequence, $g_2(q, τ)$ over a long time span can be measured with orders of magnitude lesser number of frames. The performance of these XPCS acquisition schemes is demonstrated using slowly relaxing model colloidal suspensions. Furthermore, an analytical expression is provided for the quantitative description of full $g_2(q, τ)$.
