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      • Controlling the Valence State of Cu Dopant in α-Fe<sub>2</sub>O<sub>3</sub> Anodes: Effects on Crystal Structure and the Conversion Reactions with Alkali Ions

        Zhang, Jiliang,Lau, Vincent Wing-hei,Liao, Chang-Zhong,Wong, Kam Wa,Lee, Gi-Hyeok,Zou, Feng,Chang, Chung-Kai,Sheu, Hwo-Shuenn,Kang, Yong-Mook American Chemical Society 2019 Chemistry of materials Vol.31 No.4

        <P>Doping is one of the most important ways to tailor the performance of energy materials. However, the crystal structure of doped materials is usually oversimplified as a simple substitution of dopants. Here, we characterized the doped α-Fe<SUB>2</SUB>O<SUB>3</SUB> with different Cu cations using synchrotron X-ray diffraction, X-ray absorption, and X-ray photoelectron spectroscopy, and electrochemically evaluated it as an anode in lithium batteries. The results suggest that doping is not the simple replacement of Fe<SUP>3+</SUP> sites by Cu<SUP>2+</SUP> or Cu<SUP>+</SUP> but induces a complex local structure change, which may be a characteristic of this class of materials. In Cu<SUP>+</SUP>-doped samples, Cu<SUP>+</SUP> not only replaces the Fe<SUP>3+</SUP> site and distorts the FeO<SUB>6</SUB> octahedra, but also gives rise to oxygen vacancies in CuO<SUB>6</SUB> octahedra in the bulk structure and peroxides at the surface, leading to uniform precipitation of Cu as a conductive and buffering agent. These CuO<SUB>6</SUB> octahedra also facilitate homogeneous reactions (electrochemical reduction of Cu<SUP>+</SUP> and Fe<SUP>3+</SUP> together) and the formation of high quality solid-electrolyte interface (SEI) layers. All these factors account for its improved electrochemical performance (discharge capacity of 841(25) mAh/g against 758(21) mAh/g of undoped one, after 80 cycles at 100mA/g). In Cu<SUP>2+</SUP>-doped samples, Cu<SUP>2+</SUP> takes both Fe<SUP>3+</SUP> and empty octahedral interstitial sites, forming linear clusters of three neighboring CuO<SUB>6</SUB> octahedra. Such medium-range phase separation causes electrochemical reduction to metallic Cu before the reduction of Fe<SUP>3+</SUP>, leading to inactive surface Cu that contributes to poor SEI layers and deteriorates its electrochemical performances. The present work allows a better understanding of how doping affects the crystallographic structures and offers insights into how this strategy can be employed to improve electrochemical performance, in contrast to the ambiguity over material properties associated with the commonly accepted model of simple atomic replacement.</P> [FIG OMISSION]</BR>

      • KCI등재

        Double hysteresis loops induced by Mn doping in Pb0.99Nb0.02(Zr0.95Ti0.05)0.98O3 ferroelectric ceramics

        Meng Jiang,Xuhai Li,Jiliang Zhu,Xiaohong Zhu,Wei Shi,Lihua Li,Dingquan Xiao,Jianguo Zhu 한국물리학회 2010 Current Applied Physics Vol.10 No.2

        Pb0.99Nb0.02(Zr0.95Ti0.05)0.98O3 (PNZT95/5) ceramics with 1 mol% and without Mn doping were prepared via conventional solid state reaction process. X-ray diffraction patterns show that the PNZT95/5 and Mn-doped PNZT95/5 (PNZTM95/5) ceramics, with composition near the boundary of the ferroelectric phase (FE)/antiferroelectric phase (AFE), have a rhombohedral perovskite structure. The ferroelectric behavior of PNZT95/5 ceramics is strongly affected by Mn doping. Without any aging process the PNZTM95/5 ceramics possess double hysteresis loops (P–E loops), whereas the PNZT95/5 ceramics possess normal single hysteresis loops. Due to the defect dipoles formed by effectively negatively charged Mn3+ dopants and positively charged O2- vacancies, the PNZTM95/5 ceramics exhibit the double P–E loops. The defect dipole effect has been proved by investigating the P–E loops under different external fields. As a result, the PNZTM95/5 ceramics become ‘‘hardened”, exhibiting a high mechanical quality factor (1300).

      • KCI등재

        Leg-Balancing Control of the DC-link Voltage for Modular Multilevel Converters

        Sixing Du,Jinjun Liu,Jiliang Lin 전력전자학회 2012 JOURNAL OF POWER ELECTRONICS Vol.12 No.5

        This paper applies carrier phase shifted pulse-width modulation (CPS-PWM) to transformerless modular multilevel converters (MMC) to improve the output spectrum. Because the MMC topology is characterized by the double-star connection of six legs consisting of cascaded modular chopper cells with floating capacitors, the balance control of the DC-link capacitor voltage is essential for safe operation. This paper presents a leg-balancing control strategy to achieve DC-link voltage balance under all operating conditions. This strategy based on circulating current decoupling control focused on DC-link balancing between the upper and lower legs in each phase pair by considering the six legs as three independent phase-pairs. Experiments are implemented on a 100-V 3-kVA downscaled prototype. The experimental results show that the proposed leg-balancing control is both effective and practical.

      • KCI등재

        Hydraulic regenerative braking system studies based on a nonlinear dynamic model of a full vehicle

        Ning Li,Xiaobin Ning,Qiucheng Wang,Jiliang Li 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.6

        To obtain a reasonable match of the main parameters of a hydraulic regenerative braking system and to improve the energy recovery efficiency, this paper establishes the corresponding mathematical models and testbed for a hydraulic regenerative braking system. The proposed system is analysed and verified through simulation and experiments. Then, the linear and nonlinear mathematical models of a full vehicle are built, with joint simulation of the hydraulic regenerative braking system, and the influence of the hydraulic regenerative braking system on braking performance under different running conditions is discussed. The results indicate that the deviations in the simulation results between the linear and nonlinear dynamic models are very small. When the brake deceleration and road adhesion coefficient are 0.2, deviations are within 1.38 %. With an increase in the braking deceleration and road adhesion coefficient, the deviations in braking time and distance between the systems become larger and larger. When the braking deceleration and road adhesion coefficient are 0.7, the deviation reaches 30 %. Finally, with braking energy recovery efficiency and braking distance as the optimization objectives, the nonlinear braking energy recovery system parameters are optimized. After optimization, the energy recovery efficiency of the nonlinear system reaches 76.3 %, and the braking distance is 22.8 m.

      • KCI등재

        Experimental study on the controlled air oxidation of sawdust in a packed-bed reactor

        Meng Qingmin,Chen Xiaoping,Bu Changsheng,Ma Jiliang 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.4

        The controlled air oxidation technology is a promising way of disposing medical waste, which has been a huge challenge in China. It converts waste through partial oxidation into a gaseous mixture, small quantities of char and condensable compounds. But operational performance of the primary chamber of the controlled air incinerator is poorly understood, leading to difficulty in control. In this paper, a packed-bed reactor was established to study the effect of O2 concentration on sawdust oxidation. The feed gas flow rate was kept constant at 0.6 m3/h at room temperature (26 oC) with O2 concentrations varied from 6% to 12%. Temperature profiles of the beds, product yields and gas compositions in the out-of-bed fuel gas were measured in detail. The results showed that the sawdust beds achieved low temperatures for the given O2 concentrations and leveled off in the oxidation processes. The bed temperatures increased and the solid yields decreased with the increase of O2 concentrations. When the O2 concentration was 10%, the gas yield reached a minimum and the liquid reached a maximum correspondingly. When the O2 concentration increased from 6% to 10%, the peak concentrations of CO and CH4 in the gas yield increased. However, when the O2 concentration exceeded 10%, CO and CH4 concentrations decreased. As O2 concentration varied from 6% to 12%, CO2 concentration increased continuously. This study provides a fundamental insight that the reaction processes could be well regulated by means of adjusting the feed air in practical units.

      • KCI등재

        MiR-183-5p Promotes Proliferation, Metastasis and Angiogenesis in Breast Cancer Cells through Negatively Regulating Four and a Half LIM Protein 1

        Yi Li,Qing'an Zeng,Jiliang Qiu,Ting Pang,Fenglian Ye,Lin Huang,Xuexia Zhang 한국유방암학회 2020 Journal of breast cancer Vol.23 No.4

        Purpose: Four and a half LIM protein 1 (FHL1) is involved in breast cancer (BC) development, but the regulatory mechanism involved remain unclear. In the present study, we examined the role of FHL1 in BC development. Methods: The expression of FHL1, miR-183-5p, and miR-96-5p in BC tissues was analyzed using StarBase analysis. FHL1 expression in BC tissues, a normal human breast epithelial cell line, and BC cell lines was detected using quantitative reverse transcription polymerase chain reaction (qRT-PCR). The relationship between FHL1 and miR-183-5p/miR-96-5p was analyzed via Pearson's rank correlation, TargetScan, and a dual-luciferase reporter assay. BT549 and MDA-MB-231 cells were transfected with either FHL1 and miR-183-5p mimics, or siFHL1 and a miR-183-5p inhibitor, respectively. The viability, colony number, migration, invasion, and tube length of BT549 and MDA-MB-231 cells were examined using cell counting kit-8, colony formation, wound-healing, Transwell, and tube formation assays, respectively. The levels of FHL1, vascular endothelial growth factor (VEGF), p53, E-cadherin, N-cadherin, and vimentin were quantified using western blotting and qRT-PCR. Results: FHL1 expression was downregulated in BC tissues and cells, whereas miR-183-5p and miR-96-5p were upregulated in BC tissues (negative correlation with FHL1 expression). FHL1 overexpression inhibited the viability, colony number, migration, and invasion of BC cells and the expression of VEGF, N-cadherin, and vimentin, and increased the expression of FHL1, p53, and E-cadherin in BT549 cells. Furthermore, a miR-183-5p mimic reversed these effects of FHL1 overexpression, whereas FHL1 silencing caused opposite results to those observed in MDA-MB-231 cells; however, this was reversed by a miR-183-5p inhibitor. Conclusion: Our study suggests that miR-183-5p promotes cell proliferation, metastasis, and angiogenesis by negatively regulating FHL1 in BC.

      • SCIESCOPUSKCI등재

        Leg-Balancing Control of the DC-link Voltage for Modular Multilevel Converters

        Du, Sixing,Liu, Jinjun,Lin, Jiliang The Korean Institute of Power Electronics 2012 JOURNAL OF POWER ELECTRONICS Vol.12 No.5

        This paper applies carrier phase shifted pulse-width modulation (CPS-PWM) to transformerless modular multilevel converters (MMC) to improve the output spectrum. Because the MMC topology is characterized by the double-star connection of six legs consisting of cascaded modular chopper cells with floating capacitors, the balance control of the DC-link capacitor voltage is essential for safe operation. This paper presents a leg-balancing control strategy to achieve DC-link voltage balance under all operating conditions. This strategy based on circulating current decoupling control focused on DC-link balancing between the upper and lower legs in each phase pair by considering the six legs as three independent phase-pairs. Experiments are implemented on a 100-V 3-kVA downscaled prototype. The experimental results show that the proposed leg-balancing control is both effective and practical.

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