An operando surface enhanced Raman spectroscopy (SERS) study of carbon deposition on SOFC anodes.

Li, Xiaxi,Liu, Mingfei,Lee, Jung-pil,Ding, Dong,Bottomley, Lawrence A,Park, Soojin,Liu, Meilin Royal Society of Chemistry 2015 Physical chemistry chemical physics Vol.17 No.33

<P>Thermally robust and chemically inert Ag@SiO2 nanoprobes are employed to provide the surface enhanced Raman scattering (SERS) effect for an in situ/operando study of the early stage of carbon deposition on nickel-based solid oxide fuel cell (SOFC) anodes. The enhanced sensitivity to carbon enables the detection of different stages of coking, offering insights into intrinsic coking tolerance of material surfaces. Application of a thin coating of gadolinium doped ceria (GDC) enhances the resistance to coking of nickel surfaces. The electrochemically active Ni-YSZ interface appears to be more active for hydrocarbon reforming, resulting in the accumulation of different hydrocarbon molecules, which can be readily removed upon the application of an anodic current. Operando SERS is a powerful tool for the mechanistic study of coking in SOFC systems. It is also applicable to the study of other catalytic and electrochemical processes in a wide range of conditions.</P>

Design and research of high misalignment tolerant magnetic couplers for dynamic wireless charging systems

Zhenjie Li,Xuezhi Yang,Jun Ma,Mingfei Ban,Yiqi Liu 전력전자학회 2024 JOURNAL OF POWER ELECTRONICS Vol.24 No.3

This paper proposes a main-auxiliary cooperative receiving coil (MA-coil) with a lower space occupation rate and a simple control based on the time-sharing working principle, which can effectively improve the anti-misalignment capability of a dynamic wireless charging (DWC) system. First, the structure and circuit topology of the MA-coil are designed. The two auxiliary coils (A-coil) are connected in reverse series and symmetrically placed on both sides of the main coil (M-coil). Second, the output performance of the MA-coil in the y-direction is calculated based on the time-sharing working principle. The A-coil works by itself and enhances the output power when side shift occurs. Third, the most suitable ratio of coil width w M and w A is determined. The anti-misalignment performance and the effective side shift range are compared through simulation between the MA-coil in this case and the square coil. Finally, an experimental prototype is built to verify the feasibility of the proposed structure, and experimental results obtained from the prototype are basically consistent with the theoretical analysis. The anti-misalignment capability of the MA-coil is more than 20% higher than that of the square coil.

Electrostatic Force Microscopic Characterization of Early Stage Carbon Deposition on Nickel Anodes in Solid Oxide Fuel Cells

Park, Hyungmin,Li, Xiaxi,Lai, Samson Y.,Chen, Dongchang,Blinn, Kevin S.,Liu, Mingfei,Choi, Sinho,Liu, Meilin,Park, Soojin,Bottomley, Lawrence A. American Chemical Society 2015 NANO LETTERS Vol.15 No.9

<P>Carbon deposition on nickel anodes degrades the performance of solid oxide fuel cells that utilize hydrocarbon fuels. Nickel anodes with BaO nanoclusters deposited on the surface exhibit improved performance by delaying carbon deposition (i.e., coking). The goal of this research was to visualize early stage deposition of carbon on nickel surface and to identify the role BaO nanoclusters play in coking resistance. Electrostatic force microscopy was employed to spatially map carbon deposition on nickel foils patterned with BaO nanoclusters. Image analysis reveals that upon propane exposure initial carbon deposition occurs on the Ni surface at a distance from the BaO features. With continued exposure, carbon deposits penetrate into the BaO-modified regions. After extended exposure, carbon accumulates on and covers BaO. The morphology and spatial distribution of deposited carbon was found to be sensitive to experimental conditions.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2015/nalefd.2015.15.issue-9/acs.nanolett.5b02237/production/images/medium/nl-2015-02237r_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl5b02237'>ACS Electronic Supporting Info</A></P>

Wireless charging system for unmanned aerial vehicles using lightweight and compact receiver modules

Yuhong Tian,Zhenjie Li,Hao Liu,Yiqi Liu,Mingfei Ban,Junyuan Zheng 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.4

This paper proposes a wireless charging system (WCS) for unmanned aerial vehicles (UAVs) that features a lightweight andcompact receiver module and constant current/constant voltage (CC/CV) charging. Optimizing the LCC-none compensation topology reduces the weight and volume of the receiver module mainly by avoiding the secondary-side resonant capacitors. In addition, high system performance similar to that of the LCC-S compensation topology is achieved. A magnetic coupler with dual power transfer channels is designed using the specific structure of the UAV. The reasonable charging zone is determined by optimizing the magnetic coupler parameters. Besides, a primary-side PI-controlled Buck converter is used to realize CC/CV charging with a high system efficiency under a suitable misalignment range to avoid the secondary-side circuit and control complexity. Finally, both simulation and experimental results verify the feasibility of the designed WCS. The total weight of the receiver coil is only 54 g. During 5 A CC charging, the tested maximum output power and system efficiency values are 90 W and 87.2%, respectively.

MMC‑modified sub‑module structure with double reverse blocking IGBTs

Yiqi Liu,Zhaoyu Duan,Qichao Chen,Bingkun Li,Mingfei Ban,Zhenjie Li 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.3

In high-voltage direct current (HVDC) systems, among the voltage source converters (VSCs), the modular multilevel converter (MMC) is a popular choice for power transmission. Unfortunately, the conventional half-bridge sub-module (SM) cannot deal with DC faults by itself. Thus, improved SM topologies enabling DC fault ride-through are significant. With this in mind, an MMC-modified SM structure is presented with double reverse blocking IGBTs (DRBSM). When all of the IGBTs in an MMC are blocked, the DRBSM can insert two capacitors in series to the fault circuit to rapidly overcome the DC fault. First, the DRBSM topology and working principle are analyzed. Second, the DRBSM control strategy is illustrated. Third, the device withstand voltage, DC fault ride-through, cost, and loss performance of the DRBSM are presented in detail. Finally, according to simulation results, the DRBSM fault ride-through speed is shown to be as fast as the full-bridge SM, and faster than the clamp double SM. In addition, experimental results validate the feasibility of the proposed DRBSM structure.

Investigation of Rebar Exposure Issues of Diaphragm Wall and Influencing Factors Analysis

Liyuan Tong,Qiwen Guo,Hongbo Che,Mingfei Zhang,Huangsong Pan,Hongjiang Li 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.4

The exposure of rebar in diaphragm wall was discovered after excavation in more than 20 subway stations, along the lines 1 to 4 in Suzhou, China. Such phenomena were investigated from strata formation, hydrogeological condition, construction techniques, adjacent surcharge load and other aspects. Based on field investigation, in situ testing and numerical simulation, the disturbance of trenching operations and the main factors that affect the stability of the diaphragm wall during the trenching process are analyzed comprehensively. The results show that the deformation behavior and stability of slurry trench walls are mainly influenced by strata characteristics, adjacent surcharge loading, formation of bentonite filter cake on trench walls, pressure of a confined aquifer, height of slurry filling and slurry density. The underground water pressure in the confined aquifer of silty soil layers is considered as one of the main controlling factors, which is verified by the subsequently dewatering and trenching tests. During the construction process, the deformation and stability of the trench walls can be improved by adjusting and controlling the crucial controlling factors. Further, relevant remedial measures as well as the preventive methods during the process of constructing diaphragm walls and subsequent soil excavation are addressed.

Identification of a 193 bp promoter region of TaNRX1‑D gene from common wheat that contributes to osmotic or ABA stress inducibility in transgenic Arabidopsis

Cheng Jie,Wei Fan,Zhang Mingfei,Li Nan,Song Tianqi,Wang Yong,Chen Dongsheng,Xiang Jishan,Zhang Xiaoke 한국유전학회 2021 Genes & Genomics Vol.43 No.9

Background Cloning and characterizing the drought-inducible promoters is essential for their use in crop resistance’s genetic improvement. Previous studies have shown that the TaNRX1-D gene participates in regulating the response of wheat to drought stress. However, its promoter has not yet been identifed. Objective In this study, we aimed to characterize the promoter of the TaNRX1-D gene. Methods The promoter of TaNRX1-D (named P0, 2081 bp) was isolated from common wheat with several cis-acting elements that regulate in response to abiotic stresses and some core cis-acting elements. Functional verifcation of the promoter, eight 5′-deletion fragments of TaNRX1-D promoter, was fused to the β-glucuronidase (GUS) gene P0::GUS~P7::GUS and transformed into Arabidopsis, respectively. Agrobacterium-mediated GUS transient assay the P6a and P6b promoter regions in tobacco leaves under normal, osmotic or ABA stress. Results Activity analysis of the full-length promoter (P0) showed that the intensity of stronger β-glucuronidase (GUS) staining in the roots and leaves was obtained during the growth of transgenic Arabidopsis. P0::GUS displayed the GUS activity was much higher in the roots and leaves than in other parts of the transgenic plant under normal conditions, which was similarly within wheat. Analysis of the 5′-deletion fragments revealed that P0::GUS~P6::GUS responded well upon exposure to osmotic (polyethylene glycol-6000, PEG6000) and abscisic acid (ABA) stress treatments and expressed signifcantly higher GUS activity than the CaMV35S promoter (35S::GUS), while P7::GUS did not. GUS transient assay in tobacco leaves showed that the GUS activities of P6a and P6b were lower than P6 in the PEG6000 and ABA stresses. Conclusion The 193 bp (P6) segment was considered the core region of TaNRX1-D responding to PEG6000 or ABA treatment. GUS activity assay in transgenic Arabidopsis showed that this segment was sufcient for the PEG6000 or ABA stress response. The identifed 193 bp promoter of TaNRX1-D in this study will help breed osmotic or ABA tolerant crops. The 36 bp segment between P6 and P6b (−193 to −157 bp) was considered the critical sequence for the TaNRX1-D gene responding to PEG6000 or ABA treatment.

Analysis and Design of Seismic Robustness of FRP-Reinforced Frame based on Interlayer Displacement

Guohua Sheng,Quan Bai,Shengji Jin,He Yu,Mingfei Li 대한토목학회 2019 KSCE Journal of Civil Engineering Vol.23 No.6

For a structure, robustness is a high-level performance index since it takes account of the effects of impact, explosion, earthquake and other instantaneous dynamic actions on the structure safety. In this work, layer is taken as the tie between the column and the frame. Two concepts, namely, “layer importance coefficient” of the column and “layer vulnerability coefficient” of the frame, are introduced. Based on these, the method for calculating the seismic robustness is proposed and analyzes the seismic robustness of three FRP-reinforced frame models. The results show that: The robustness of the frame with the 1st layer column reinforced with two layer CFRP (carbon fiber reinforced polymer) (F20RC) and the 1st and 2nd layer column reinforced with one layer CFRP (F11RC), respectively are better than that of the 1st layer column reinforced with one layer CFRP (F10RC). As the intensity of earthquake action increases, the seismic robustness index decreases. When UBC97's acceleration-related parameter Ca = 0.36 and velocityrelated parameter Cv = 0.36, the robustness coefficient of the three models F20RC, F11RC, F10RC are 36.5, 37.2, 34.1, respectively. When Ca = 0.6, Cv = 0.6, that of F20RC, F11RC, F10RC are 24.2, 20.4, 19.5, respectively. Finally, the procedure for designing the FRP-reinforced frame based on the seismic robustness is presented and demonstrated.