Abstract —The research cycle of thermal properties of water clusters in polysaccharide–water systems (starch and Sephadex G-100) with a low content of freezing water was continued based on the example of another modified polysaccharide, Sephadex G-25. This Sephadex has a more rigid three-dimensional structure compared with Sephadex G-100. The doublet structure of the melting curve of water clusters, which indicated the bimodal nature of their size distribution, was the main peculiarity of the data obtained for Sephadex G-25 by differential scanning calorimetry. The observed decrease in the temperature and heat of melting and crystallization of water clusters with a decrease in the humidity of Sephadex G-25, as in the case of other polysaccharides, was a typical manifestation of the size effect for nanosystems. At the same time, hysteresis occurred between the temperatures $$\Delta T = {{T}_{{{\text{mel}}}}} - {{T}_{{{\text{cr}}}}}$$ , and the heats $$\Delta Q = {{Q}_{{{\text{mel}}}}} - {{Q}_{{{\text{cr}}}}}$$ of these transitions, which is also typical for small systems. It was found that the transformation processes (recrystallization, reorganization, and size change) in the system of clusters of crystallized supercooled water in Sephadex G-25 with low humidity during heating could occur both below the melting interval and inside it, which indicated the nonequilibrium state of the original set of nanoclusters. It was shown that the decrease of V heat , as well as annealing within the melting interval led to a redistribution of clusters in size and, according to the revealed size effect, to an increase in the melting heat. These facts taken together indicated that the nonequilibrium state of the initially formed clusters during cooling and, as a consequence, their ability to transform with increasing temperature certainly play an important, if not a decisive, role in the manifestation of hysteresis in the thermal properties of water nanoclusters.

中文翻译：

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基于G型湿Sephadex中过冷水团簇的纳米系统热性能滞后的表现

摘要——以另一种改性多糖Sephadex G-25为例，继续研究低冷冻水含量的多糖-水体系（淀粉和Sephadex G-100）中水团簇的热学性质。与Sephadex G-100相比，这款Sephadex具有更坚固的三维结构。水团簇熔解曲线的双峰结构表明其尺寸分布的双峰性质，是通过差示扫描量热法获得的 Sephadex G-25 数据的主要特点。与其他多糖的情况一样，随着 Sephadex G-25 湿度的降低，观察到的水团簇熔化和结晶的温度和热量降低，这是纳米系统尺寸效应的典型表现。同时，滞后发生在温度 $$\Delta T = {{T}_{{{\text{mel}}}}} - {{T}_{{{\text{cr}}}}}$$ 和这些跃迁的热量 $$\Delta Q = {{Q}_{{{\text{mel}}}}} - {{Q}_{{{\text{cr}}}}}}$$对于小型系统也是典型的。研究发现，加热过程中低湿度Sephadex G-25中结晶过冷水团簇系统的转变过程（重结晶、重组和尺寸变化）在熔化区间以下和内部都可能发生，表明非平衡态原始纳米团簇的状态。结果表明，V heat 的降低以及熔化区间内的退火导致簇的尺寸重新分布，并且根据揭示的尺寸效应，熔化热增加。