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Aliyu D. Mohammed Desmond A. Young Hermanus C. M. Vosloo 《Research on Chemical Intermediates》2017,43(4):2187-2200
Glycerol acrylate (GA) is synthesised by an acryloylation reaction with acryloyl chloride. An ester was used as a cross-linking agent at varying proportions in the synthesis of poly acrylic acid (PAA). The amount of cross-linking density in the product (GA-PAA) and degree of neutralisation determine the absorbency of the polymer samples. A sample of GA-PAA containing 0.8 % GA was discovered to absorb 395 and 66 g/g of water and saline solution, respectively. Different solvent uptakes were tested with the sample showing varying capacity for different solvents. The temperature of the reaction was maintained at 60 °C and a reaction time of 2½ h. FTIR, TGA, SEM and XRD analyses were used to characterise the products. 相似文献
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Zhuangzhuang Liu Aimin Sha Liqun Hu Yongwei Lu Wenxiu Jiao Zheng Tong Jie Gao 《Chemical Papers》2017,71(4):741-751
Portland cement have to hydrate in cold climates in some particular conditions. Therefore, a better understanding of cement hydration under low temperatures would benefit the cement-based composites application. In this study, Portland cement was, therefore, kinetically and thermodynamically simulated based on a simple kinetics model and minimization of Gibbs free energy. The results of an evaluation indicate that Portland cement hydration impact factors include the water–cement ratio (w/c), temperature, and specific surface area, with the latter being an especially remarkable factor. Therefore, increasing the specific surface area to an appropriate level may be a solution to speed the delayed hydration due to low temperatures. Meanwhile, the w/c ratio is believed to be controlled under cold climates with consideration of durability. The thermodynamic calculation results suggest that low-temperature influences can be divided into three levels: irrevocable effects (<0 °C), recoverable effects (0–10 °C), and insignificant effects (10–20 °C). Portland cement was additionally measured via X-ray diffraction, thermal gravity analysis, and low-temperature nitrogen adsorption test in a laboratory and comparisons were drawn that validate the simulation result. 相似文献
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In this work we consider open quantum random walks on the non-negative integers. By considering orthogonal matrix polynomials we are able to describe transition probability expressions for classes of walks via a matrix version of the Karlin–McGregor formula. We focus on absorbing boundary conditions and, for simpler classes of examples, we consider path counting and the corresponding combinatorial tools. A non-commutative version of the gambler’s ruin is studied by obtaining the probability of reaching a certain fortune and the mean time to reach a fortune or ruin in terms of generating functions. In the case of the Hadamard coin, a counting technique for boundary restricted paths in a lattice is also presented. We discuss an open quantum version of Foster’s Theorem for the expected return time together with applications. 相似文献
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