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1,937 results on '"Sun, Jianfeng"'

154. Polyelectrolyte complex gels used for CO2 absorption.

Author

Huang, Junjie, Wu, Dianguo, Liu, Weidong, Sun, Jianfeng, Zhao, Xuezhi, Zhang, Yan, and Feng, Yujun

Subjects
POLYELECTROLYTES, ABSORPTION, CARBON dioxide, GAS leakage, ELECTROSTATICS
Abstract

Polymer gels have shown application potential in minimizing gas channeling during CO2 enhanced oil recovery and storage processes, but the pumping pressure of preformed gels was too high, and the in‐situ cross‐linking in reservoirs was uncontrollable. Here we developed polyelectrolyte complex gels through the columbic attraction between sodium carboxymethyl cellulose (NaCMC) and protonated polyethyleneimine (PEI+) by CO2 in the presence of water. Without CO2, the viscosity of polymer complex solution is relatively low; after streaming CO2, the viscosity of the NaCMC‐PEI+ mixture aqueous solution increases significantly, forming a gel. It was also found that the complex solution shows an evolution of "sol–gel‐separated phase" as the polymer concentration increases, which could be attributed to the enhanced electrostatic attraction between CMC− and PEI+. The viscosity of the gel decreases upon increasing salinity owing to the reduced charge repulsion by the introduced inorganic salt. The CMC−‐PEI+ complex can retain its gel behavior until 60°C, after which the complex collapses. The uptake tests show that 11.34 mg CO2 can be absorbed by each gram of gel composed of 0.9 wt% NaCMC and 0.15 wt% PEI at room temperature and ambient pressure. This work provides an inexpensive route to control gas leakoff and improve CO2 absorption. [ABSTRACT FROM AUTHOR]

Published
2024
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155. Experimental and numerical research on the bogie hunting of a high-speed train caused by the empty stroke of yaw damper.

Author

Guo, Zhaotuan, Chi, Maoru, Sun, Jianfeng, Li, Yixiao, and Dai, Liangcheng

Subjects
HIGH speed trains, DYNAMIC stiffness, HUNTING
Abstract

The yaw damper serves as a hydraulic system connecting the bogie frame with the carbody and is the most critical component to prevent unstable oscillations of high-speed vehicles. Accidently, some unexpected factors can cause the yaw damper to fail, resulting in vehicle hunting instability. In this paper, a severe bogie-hunting phenomenon was monitored during the operation of a Chinese high-speed train. Specific research on the cause and solutions was performed by experimental and numerical methods. The wheel-rail contact relationship and the dynamic performance of the yaw damper were measured and analysed to identify the primary contributor to violent bogie hunting. The results indicated that the abnormal dynamic stiffness and damping of the yaw damper caused by the compression empty stokes serve as the primary origin of this abnormal vibration. The multi-body dynamics model of the high-speed train was established by integrating the field-tested parameters. The bogie hunting phenomenon was reproduced successfully, and the influences of yaw damper parameters on bogie hunting stability were analysed to propose the optimisation scheme. Finally, two solutions were adopted to suppress the empty compression strokes of the yaw damper and verified by the roller rig test. [ABSTRACT FROM AUTHOR]

Published
2024
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168. Transient Mild Photothermia Improves Therapeutic Performance of Oral Nanomedicines with Enhanced Accumulation in the Colitis Mucosa

Author

Ma, Ya, primary, Gou, Shuangquan, additional, Zhu, Zhenhua, additional, Sun, Jianfeng, additional, Shahbazi, Mohammad‐Ali, additional, Si, Tieyan, additional, Xu, Cheng, additional, Ru, Jinlong, additional, Shi, Xiaoxiao, additional, Reis, Rui L., additional, Kundu, Subhas C., additional, Ke, Bowen, additional, Nie, Guangjun, additional, and Xiao, Bo, additional

Published
2024
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171. 深空激光扩频通信测距一体化技术（特邀）

Author

Li Chaoyang, 李超洋, primary, Sun Jianfeng, 孙建锋, additional, Lu Zhiyong, 卢智勇, additional, Zhou Yu, 周煜, additional, Zhang Longkun, 张龙坤, additional, Jiang Yuxin, 姜玉鑫, additional, Xu Lingling, 许玲玲, additional, Pan Hanrui, 潘含蕊, additional, Jia Honghui, 贾弘辉, additional, Yuan Haoming, 袁浩铭, additional, Chen Weibiao, 陈卫标, additional, and He Hui, 贺辉, additional

Published
2024
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186. Polyelectrolyte complex gels used for CO2absorption

Author

Huang, Junjie, Wu, Dianguo, Liu, Weidong, Sun, Jianfeng, Zhao, Xuezhi, Zhang, Yan, and Feng, Yujun

Abstract

Polymer gels have shown application potential in minimizing gas channeling during CO2enhanced oil recovery and storage processes, but the pumping pressure of preformed gels was too high, and the in‐situ cross‐linking in reservoirs was uncontrollable. Here we developed polyelectrolyte complex gels through the columbic attraction between sodium carboxymethyl cellulose (NaCMC) and protonated polyethyleneimine (PEI+) by CO2in the presence of water. Without CO2, the viscosity of polymer complex solution is relatively low; after streaming CO2, the viscosity of the NaCMC‐PEI+mixture aqueous solution increases significantly, forming a gel. It was also found that the complex solution shows an evolution of “sol–gel‐separated phase” as the polymer concentration increases, which could be attributed to the enhanced electrostatic attraction between CMC−and PEI+. The viscosity of the gel decreases upon increasing salinity owing to the reduced charge repulsion by the introduced inorganic salt. The CMC−‐PEI+complex can retain its gel behavior until 60°C, after which the complex collapses. The uptake tests show that 11.34 mg CO2can be absorbed by each gram of gel composed of 0.9 wt% NaCMC and 0.15 wt% PEI at room temperature and ambient pressure. This work provides an inexpensive route to control gas leakoff and improve CO2absorption.

Published
2024
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190. Mitigation of the impact of Doppler shift on ranging accuracy

Author

Li, Chaoyang, primary, Sun, Jianfeng, additional, Lu, Zhiyong, additional, Zhou, Yu, additional, Zhang, Longkun, additional, Ren, Weijie, additional, Jiang, Yuxin, additional, Xu, Lingling, additional, Pan, Hanrui, additional, Chen, Weibiao, additional, and He, Hui, additional

Published
2023
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