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Jian Xiao,Gang Xu,Lu Wang,Pengyu Li,Wenqin Zhang,Ning Ma,Minli Tao 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.77 No.-
Four categories of sulfonic acid functionalizedfiber catalysts with different surface microenvironmentswere synthesized by covalent grafting using polyacrylonitrilefiber (PANF) as the support. After the effectof acid structure on catalytic activity has been investigated by Friedlander reaction, PANEOSF was chosenfor the synthesis of quinolines and coumarin derivatives with high yields and extensive substrate scope(51 examples) in ethanol or water. The effect of electrostatic microenvironment and solvent has beendiscussed, and a “release-catch-release-catch” catalytic pattern was proposed accordingly. PANEOSF canbe easily recycled for 20 times without any decrease of catalytic activity.
Jianxiao Yang,Koji Nakabayashi,Jin Miyawaki,윤승호 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.34 No.-
A spinnable pitch was developed from the tetrahydrofuran-soluble fractions (THFS) of hyper coal (HPC)and used to prepare carbon fibers. THFS-derived pitch from bituminous coal-derived HPC showedexcellent spinnability and the obtained carbon fibers had a tensile strength of over 800 MPa with adiameter of 13 mm following heat treatment at 800 8C for 5 min. Thus, HPC was shown to be a usefulalternative precursor for the preparation of low-cost and general-performance carbon fibers.
Jianxiao Yang,Kui Shi,Xuanke Li,Seong-Ho Yoon 한국탄소학회 2018 Carbon Letters Vol.25 No.-
In this study, we tried to prepare an isotropic spinnable pitch which can be useful to prepare the general purpose carbon fiber through the co-carbonization of biomass tar with ethylene bottom oil under two different preparation methods (atmospheric distillation, pressurized distillation). The results showed that the ethylene bottom oil added co-carbonization was very effective to decrease of the oxygen contents for obtaining a stable spinnable pitch. The pressurized distillation was more effective to reduce the oxygen functional groups of pitches than atmospheric distillation. The obtained spinnable pitch by the pressurized distillation showed higher pitch yield of 42% and lower oxygen content of 9.12% than the spinnable pitch by the atmospheric distillation. The carbon fiber derived from the pressurized distillation spinnable pitch by carbonization at 800ºC for 5 min showed that the higher tensile strength of carbon fiber was increased up to 800 MPa.
Xiaodong Wang,Jianxiao Zou,Zhenhua Dong,Chuan Xie,Kai Li,Josep M. Guerrero 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.5
This paper proposes a novel common-mode voltage (CMV) elimination (CMV-EL) method based on model predictive control (MPC) to eliminate CMV for three-level T-type inverters (3LT²Is). In the proposed MPC method, only six medium and one zero voltage vectors (VVs) (6MV1Z) that generate zero CMV are considered as candidates to perform the MPC. Moreover, the influence of dead-time effects on the CMV of the MPC-based 6MV1Z method is investigated, and the candidate VVs are redesigned by pre-excluding the VVs that will cause CMV fluctuations during the dead time from 6MV1Z. Only three or five VVs are included to perform optimization in every control period, which can significantly reduce the computational complexity. Thus, a small control period can be implemented in the practical applications to achieve improved grid current performance. With the proposed CMV-EL method, the CMV of the 3LT²Is can be effectively eliminated. In addition, the proposed CMV-EL method can balance the neutral point potentials (NPPs) and yield satisfactory performance for grid current tracking in steady and dynamic states. Simulation and experimental results are presented to verify the effectiveness of the proposed method.
Jiangfan Shi,Yize Liu,Jianxiao Yang,Jun Li,Chong Ye,Dong Huang,Jinshui Liu,Xuanke Li 한국섬유공학회 2020 Fibers and polymers Vol.21 No.8
An upgrade synthesis method of electroless copper plating was developed to prepare the copper-coated mesophasepitch-based carbon fibers (Cu@CF) with APTES (3-Aminopropyl triethoxysilane) grafting modification. The microstructureand properties of the fibers which were prepared by the APTES sensitization method were investigated and compared withthose prepared by the conventional SnCl2 sensitization method. The results showed that as-coated fibers sensitized by APTESdemonstrated to have better interfacial cohesion between the copper layer and the fiber surface than those sensitized by SnCl2did. Moreover, the resistivity of Cu@CF-APTES declined to 2.3±0.9 μΩ·cm, while that of Cu@CF-SnCl2 was 9.3±3.7μΩ·cm. Besides, not only the strength of Cu@CF-APTES increased, but the strength discreteness of them reduced due to thefact that no peeling phenomenon was observed between the copper layer and fiber during the stretch test.
Munir, Hafiz Mudassir,Zou, Jianxiao,Xie, Chuan,Li, Kay,Younas, Talha,Guerrero, Josep M. The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.1
The application of shunt active power filters (S-APFs) is considered to be the most popular approach for harmonic compensation due to its high simplicity, ease of installation and efficient control. Its functionality mainly depends upon the rapidness and precision of its internally built control algorithms. A S-APF is generally operated in the current controlled mode (CCM) with the detection of harmonic load current. Its operation may not be appropriate for the distributed power generation system (DPGS) due to the wide dispersion of nonlinear loads. Despite the fact that the voltage detection based resistive-APF (R-APF) appears to be more appropriate for use in the DPGS, the R-APF experiences poor performance in terms of mitigating harmonics and parameter tuning. Therefore, this paper introduces a direct harmonic voltage detection based control approach for the S-APF that does not need a remote harmonic load current since it only requires a local point of common coupling (PCC) voltage for the detection of harmonics. The complete design procedure of the proposed control approach is presented. In addition, experimental results are given in detail to validate the performance and superiority of the proposed method over the conventional R-APF control. Thus, the outcomes of this study approve the predominance of the discussed strategy.
Wang, Xiaodong,Zou, Jianxiao,Dong, Zhenhua,Xie, Chuan,Li, Kai,Guerrero, Josep M. The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.5
This paper proposes a novel common-mode voltage (CMV) elimination (CMV-EL) method based on model predictive control (MPC) to eliminate CMV for three-level T-type inverters (3LT2Is). In the proposed MPC method, only six medium and one zero voltage vectors (VVs) (6MV1Z) that generate zero CMV are considered as candidates to perform the MPC. Moreover, the influence of dead-time effects on the CMV of the MPC-based 6MV1Z method is investigated, and the candidate VVs are redesigned by pre-excluding the VVs that will cause CMV fluctuations during the dead time from 6MV1Z. Only three or five VVs are included to perform optimization in every control period, which can significantly reduce the computational complexity. Thus, a small control period can be implemented in the practical applications to achieve improved grid current performance. With the proposed CMV-EL method, the CMV of the $3LT^2Is$ can be effectively eliminated. In addition, the proposed CMV-EL method can balance the neutral point potentials (NPPs) and yield satisfactory performance for grid current tracking in steady and dynamic states. Simulation and experimental results are presented to verify the effectiveness of the proposed method.
Hafiz Mudassir Munir,Jianxiao Zou,Chuan Xie,Kay Li,Talha Younas,Josep M. Guerrero 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.1
The application of shunt active power filters (S-APFs) is considered to be the most popular approach for harmoniccompensation due to its high simplicity, ease of installation and efficient control. Its functionality mainly depends upon therapidness and precision of its internally built control algorithms. A S-APF is generally operated in the current controlled mode(CCM) with the detection of harmonic load current. Its operation may not be appropriate for the distributed power generationsystem (DPGS) due to the wide dispersion of nonlinear loads. Despite the fact that the voltage detection based resistive-APF(R-APF) appears to be more appropriate for use in the DPGS, the R-APF experiences poor performance in terms of mitigatingharmonics and parameter tuning. Therefore, this paper introduces a direct harmonic voltage detection based control approach forthe S-APF that does not need a remote harmonic load current since it only requires a local point of common coupling (PCC)voltage for the detection of harmonics. The complete design procedure of the proposed control approach is presented. In addition,experimental results are given in detail to validate the performance and superiority of the proposed method over the conventionalR-APF control. Thus, the outcomes of this study approve the predominance of the discussed strategy.
Wu Wei,Zhang Xiaxiang,Yang Jianxiao,Lijun Cai,Li Xuanke 한국탄소학회 2020 Carbon Letters Vol.30 No.6
The oxygen-rich activated carbon (AC) was facilely developed using petroleum coke as a raw material by KOH activa�tion under the rapid heating rate. The porosity and surface chemistry of ACs prepared under diferent heating rates were characterized and their adsorption properties for methylene blue (MB) were investigated. The results showed that the AC5 prepared under the heating rate of 5 °C min−1 had the highest surface area compared with the AC10, AC15 or AC20, while the AC20 prepared under the heating rate of 20 °C min−1 consisted of the highest oxygen content and most –OH functional group compares with the other ACs. These indicated that rapid heating rate was against the formation of more developed porosity, however, it was benefcial to producing more oxygen functional groups. As to MB adsorption, AC15 exhibited the maximum adsorption capacity for MB of 884 mg g−1 due to high surface area of 2803 m2 g−1 and high oxygen content of 23.27%. Moreover, despite the fact that AC20 had much lower surface area than the AC5, the AC20 showed higher MB adsorption capacity than the AC5. This was because the AC20 has the highest content of –OH, which was a positive impetus for MB adsorption. Therefore, rapid heating rate was an efective and simple approach to preparing the oxygen-rich ACs for improving the adsorption capacity of MB.