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Yongxin Li,Yining Hu,Fu Huang,Shuqin Li,Zhibin Sun 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.8
The discrete technique combined with the upper bound approach is applied to analyze the stability of soil slopes with multiple layers in this paper. Based on the geometrical relationship derived from the normality requirement, an algorithm is proposed to determine the coordinates of discrete points on the failure surface. Specifically, these points are generated from the initial point to the terminal point. After completion of the discrete sliding surface, the sliding block is sliced by the vertical slice technique. Equations with integral form for rates of internal energy dissipation and external work are then derived. The scheme for calculation of the safety factor is presented by means of the strength reduction method and the optimization algorithm. Comparison analysis based on four examples under various conditions demonstratesthe validity of the proposed method in addressing stability problem of slopes with multiple layers.
Synthesis, surface adsorption and micelle formation of a class of morpholinium gemini surfactants
Caili Dai,Sisi Fang,Mei Hu,Xiaojuan He,Mingwei Zhao,Xuepeng Wu,Shuai Yang,Yining Wua 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.54 No.-
A series of novel gemini surfactants with morpholinium headgroup, 4, 40-(alkane-4, n-40)bis(4-decyl, dodecyl or tetradecyl morpholinium)bromide (Mm-n-Mm, m = 10, 12, 14, n = 3, 4), were synthesized and characterized using 1H NMR. The surfactants were investigated for their adsorption and micellization in aqueous solutions through surface tension and conductivity methods It was found that the physicochemical properties, such as surface activity and thermodynamic property of the aqueous surfactant system, were dependent on the lengths of both hydrophobic tail chain and spacer. With the increase of the hydrophobic chain length or the decrease of spacer length, the cmc value of the surfactant decreases and the ability to reduce the surface tension is stronger. The calculation result of thermodynamic parameters indicated that the surfactants we synthesized are more inclined to aggregate in solution as compared with traditional m-s-m type gemini surfactants, and the micellization of Mm-n-Mm was an entropy-driven process.