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638 results on '"Huo, Feng"'

103. Ionic liquid-air interface probed by sum frequency generation spectroscopy and molecular dynamics simulation: influence of alkyl chain length and anion volume

Author

Huo, Feng, Ding, Jian, Tong, Jiahuan, and He, Hongyan

Abstract

Understand the structure of the ILs/air interface on a molecular level is significant. In this work, the liquid-air interface of a class of ILs containing 1-alkyl-3-methylimidazolium cations ([Cnmim]+, n = 4, 6 and 8) was investigated by a sum-frequency generation vibrational spectroscopy experiment. The length of the alkyl chain of cations and anion type (tetrafluoroborate ([BF4]−), thiocyanate ([SCN]−), dicyanamide ([DCA]−), hexafluorophosphate ([PF6]−)) were varied to determine their intrinsic effects to the micro-structure on the interface. Meanwhile, combining with the experiment, the orientation angle and surface density for cations and anions of ILs at the air interface was analyzed by molecular dynamics simulation. It is found that the butyl side chain of cations protrudes out into the air as well as the orientation angle between the side chain and interface is 30°–50°. Meanwhile, the anion volume of ILs has almost no influence on the butyl side chain and the methyl on the side chains tend almost planar to the interface with the increased chain length. This research is highly significant for the theoretical and quantitative understanding of the interface chemistry of imidazole-based ILs.

Published
2022
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122. Electric field calculation and grading ring design for 750 kV four‐circuits transmission line on the same tower with six cross‐arms

Author

Liu Qin, Lei Chu, Huo Feng, Zhang Peng, Wang Xuezong, and Yiliang Yu

Subjects
composite insulator, four-circuits transmission line, installation position, Materials science, size 700.0 mm to 900.0 mm, corona level reduction, optimisation, size 100.0 mm, power transmission lines, finite element method, end fitting protection, Energy Engineering and Power Technology, finite element analysis, pipe diameter, electric fields, electric field strength, Transmission line, Electric field, size 150.0 mm to 250.0 mm, transmission corridors, electric field calculation, Grading (tumors), Electronic circuit, Ring (mathematics), transmission line design, business.industry, grading ring design, General Engineering, composite insulators, electric field distribution, Structural engineering, poles and towers, voltage 750.0 kV, cross-arms tower, lcsh:TA1-2040, structure optimisation, ring diameter, lcsh:Engineering (General). Civil engineering (General), business, corona, Tower, Software
Abstract

The transmission corridors can be effectively saved using 750 kV four-circuit transmission line on the same tower. In order to reduce the corona level, structure optimisation of fittings plays an important role in the transmission line design. In this study, the electric field distribution of 750 kV transmission line on six cross-arms tower was calculated based on finite element method, and the influences of pipe diameter, ring diameter and installation position of the grading ring were analysed. The results show that the increase of pipe diameter can reduce the electric field strength of grading ring while the increase of installation position and decrease of ring diameter are important to protect the end fitting of composite insulator. When using grading ring with the pipe diameter of 100 mm, the ring diameter of 700–900 mm and the installation position of 150–250 mm, the electric field strength can be controlled in a reasonable range. These results can provide references for the grading ring design of 750 kV four-circuit transmission line on the same tower.

Published
2018

127. Hydrated Ionic Liquids Boost the Trace Detection Capacity of Proteins on TiO2 Support

Author

Dong, Yihui, Laaksonen, Aatto, Huo, Feng, Gao, Qingwei, Ji, Xiaoyan, Dong, Yihui, Laaksonen, Aatto, Huo, Feng, Gao, Qingwei, and Ji, Xiaoyan

Abstract

Trace detection based on surface-enhanced Raman scattering (SERS) has attracted considerable attention, and exploiting efficient strategies to stretch the limit of detection and understanding the mechanisms on molecular level are of utmost importance. In this work, we use ionic liquids (ILs) as trace additives in a protein-TiO2 system, allowing us to obtain an exceptionally low limit of detection down to 10(-9) M. The enhancement factors (EFs) were determined to 2.30 x 10(4), 6.17 x 10(4), and 1.19 x 10(5), for the three systems: one without ILs, one with ILs in solutions, and one with ILs immobilized on the TiO2 substrate, respectively, corresponding to the molecular forces of 1.65, 1.32, and 1.16 nN quantified by the atomic force microscopy. The dissociation and following hydration of ILs, occurring in the SERS system, weakened the molecular forces but instead improved the electron transfer ability of ILs, which is the major contribution for the observed excellent detection. The weaker diffusion of the hydrated IL ions immobilized on the TiO2 substrate did provide a considerably greater EF value, compared to the ILs in the solution. This work clearly demonstrates the importance of the hydration of ions, causing an improved electron transfer ability of ILs and leading to an exceptional SERS performance in the field of trace detection. Our results should stimulate further development to use ILs in SERS and related applications in bioanalysis, medical diagnosis, and environmental science.

Published
2021
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128. The dynamic behavior and intrinsic mechanism of CO2absorption by amino acid ionic liquids

Author

Tong, Jiahuan, Zhao, Yuanyue, Huo, Feng, Guo, Yandong, Liang, Xiaodong, von Solms, Nicolas, He, Hongyan, Tong, Jiahuan, Zhao, Yuanyue, Huo, Feng, Guo, Yandong, Liang, Xiaodong, von Solms, Nicolas, and He, Hongyan

Abstract

Reducing carbon dioxide emissions is one of the possible solutions to prevent global climate change, which is urgently needed for the sustainable development of our society. In this work, easily available, biodegradable amino acid ionic liquids (AAILs) with great potential for CO2absorption in the manned closed space such as spacecraft, submarines and other manned devices are used as the basic material. Molecular dynamics simulations andab initiocalculations were performed for 12 AAILs ([P4444][X] and [P66614][X], [X] = X = [GLy]−, [Im]−, [Pro]−, [Suc]−, [Lys]−, [Asp]2−), and the dynamic characteristics and the internal mechanism of AAILs to improve CO2absorption capacity were clarified. Based on structural analysis and the analysis of interaction energy including van der Waals and electrostatic interaction energy, it was revealed that the anion of ionic liquids dominates the interaction between CO2and AAILs. At the same time, the CO2absorption capacity of AAILs increases in the order [Asp]2−< [Suc]−< [Lys]−< [Pro]−< [Im]−< [Gly]−. Meanwhile, the synergistic absorption of CO2by multiple-sites of amino and carboxyl groups in the anion was proved by DFT calculations. These findings show that the anion of AAILs can be an effective factor to regulate the CO2absorption process, which can also provide guidance for the rational and targeted molecular design of AAILs for CO2capture, especially in the manned closed space.

Published
2021

140. The Effect of Concentration of Lithium Salt on the Structural and Transport Properties of Ionic Liquid-Based Electrolytes

Author

Tong, Jiahuan, Wu, Shengli, von Solms, Nicolas, Liang, Xiaodong, Huo, Feng, Zhou, Qing, He, Hongyan, Zhang, Suojiang, Tong, Jiahuan, Wu, Shengli, von Solms, Nicolas, Liang, Xiaodong, Huo, Feng, Zhou, Qing, He, Hongyan, and Zhang, Suojiang

Abstract

Ionic liquids (ILs) are used as electrolytes in high-performance lithium-ion batteries, which can effectively improve battery safety and energy storage capacity. All atom molecular dynamics simulation and experiment were combined to investigate the effect of the concentration of lithium salt on the performance of electrolytes of four IL solvents ([Cnmim][TFSI] and [Cnmim][FSI], n = 2, 4). The IL electrolytes exhibit higher density and viscosity; meanwhile, larger lithium ion transfer numbers as the concentration of LiTFSI increases. Furthermore, in order to explore the effect of the concentration of lithium salt on the ionic associations of Li+ and anion of IL, the microstructures of the lithium salt in various IL electrolytes at different concentrations were investigated. The structural analysis indicated that strong bidentate and monodentate coordination was found between Li+ and anion of all IL electrolytes. Both cis and trans isomerism of [FSI]− were observed in [FSI]−-type IL electrolyte systems. Furthermore, the existence of the ion cluster [Li[anion]x](x−1)− in IL electrolytes and the cluster became more closed and compact as the concentration of LiTFSI increases.

Published
2020

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