Effects of Ho, Mn Co-Doping on Ferroelectric Fatigue of BiFeO3 Thin Films

Shifeng Zhao,Jieyu Chen,Wenyu Xing,Qi Yun,Wei Gao,Chenghong Nie 대한금속·재료학회 2015 ELECTRONIC MATERIALS LETTERS Vol.11 No.4

Ho, Mn, and Ho, Mn co-doped BiFeO3 thin films were deposited on Pt (100)/Ti/SiO2/Si substrates using solution gelation. The ferroelectric fatigue properties were clearly improved after doping with Ho and Mn. The doped BiFeO3 thin film displayed more strongly increased ferroelectric, leakage current, and fatigue properties compared with the pure BiFeO3 thin film. Thus, the improved performance of the BiFeO3 thin films depends on the structural transformation and reduced oxygen vacancy concentration. The present work provides a feasible approach to enhance the ferroelectric and fatigue properties of BiFeO3-based thin films.

Optical and Magnetic Properties of Copper Doped Zinc Oxide Nanofilms

Shifeng Zhao,Yulong Bai,Jieyu Chen,Alima Bai,Wei Gao 한국자기학회 2014 Journal of Magnetics Vol.19 No.1

Copper doped Zinc Oxide nanofilms were prepared using a simple and low cost wet chemical method. The microstructures, phase structure, Raman shift and optical absorption spectrum as well as magnetization were investigated for the nanofilms. Room temperature ferromagnetism has been observed for the nanofilms. Structural analyses indicated that the films possess wurtzite structure and there are no segregated clusters of impurity phase appreciating. The results show that the ferromagnetism in Copper doped Zinc Oxide nanofilms is driven either by a carrier or defect-mediated mechanism. The present work provides an evidence for the origin of ferromagnetism on Copper doped Zinc Oxide nanofilms.

An In situ Forming Hydrogel Based on Photo-Induced Hydrogen Bonding

Jingyan Zhang,Shifeng Wang,Zeren Zhao,Dong Si,Haiou Zhou,Mingdi Yang,Xianbiao Wang 한국고분자학회 2020 Macromolecular Research Vol.28 No.12

Stimulus-induced in situ forming hydrogels possess the characteristics of easy management and minimal invasiveness via simple injection at target sites with a liquid and easy forming bulk gels. In the present study, a photoreactive monomer, N'-(2-nitrobenzyl)-N-acryloyl glycinamide (NBNAGA) was introduced to modify polyacrylamide (PAM) hydrogel preparation with stimuli responsiveness. Firstly, poly(acrylamide-co-N'-(2-nitrobenzyl)-N-acryloyl glycinamide), P(AM-co-NBNAGA), copolymer solution was prepared via reversible addition fragmentation chain transfer (RAFT) polymerization using the monomers mixture of AM, NBNAGA, and N,N'- methylene bis-acrylamide (BIS). The obtained polymer solution with viscous, transparent, and flowable appearance contained weak single hydrogen bonding and slight chemical crosslinking in a microscopic perspective. Secondly, without further purification, after irradiation using UV light at 365 nm, poly(acrylamide-co-N-acryloyl glycinamide) (P(AM-co-NAGA)) hydrogel conveniently in situ formed due to the cleavage of o-nitrobenzyl groups and the corresponding emergency of dual hydrogen bonding among “uncaged” dual amide moieties. P(AM-co-NAGA) hydrogel depicted both favorable temperature sensitivity and self-healing properties, then the heating induced in vitro release profiles of doxorubicin (DOX) was analyzed.

Quantum Bee Colony Optimization and Non-dominated Sorting Quantum Bee Colony Optimization Based Multi-relay Selection Scheme

( Qiang Ji ),( Shifeng Zhang ),( Haoguang Zhao ),( Tiankui Zhang ),( Jinlong Cao ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.9

In cooperative multi-relay networks, the relay nodes which are selected are very important to the system performance. How to choose the best cooperative relay nodes is an optimization problem. In this paper, multi-relay selection schemes which consider either single objective or multi-objective are proposed based on evolutionary algorithms. Firstly, the single objective optimization problems of multi-relay selection considering signal to noise ratio (SNR) or power efficiency maximization are solved based on the quantum bee colony optimization (QBCO). Then the multi-objective optimization problems of multi-relay selection considering SNR maximization and power consumption minimization (two contradictive objectives) or SNR maximization and power efficiency maximization (also two contradictive objectives) are solved based on non-dominated sorting quantum bee colony optimization (NSQBCO), which can obtain the Pareto front solutions considering two contradictive objectives simultaneously. Simulation results show that QBCO based multi-relay selection schemes have the ability to search global optimal solution compared with other multi-relay selection schemes in literature, while NSQBCO based multi-relay selection schemes can obtain the same Pareto front solutions as exhaustive search when the number of relays is not very large. When the number of relays is very large, exhaustive search cannot be used due to complexity but NSQBCO based multi-relay selection schemes can still be used to solve the problems. All simulation results demonstrate the effectiveness of the proposed schemes.

A Novel Power Transformer Fault Diagnosis Model Based on Harris-Hawks-Optimization Algorithm Optimized Kernel Extreme Learning Machine

Han Xiaohui,Ma Shifeng,Shi Zhewen,An Guoqing,Du Zhenbin,Zhao Chunlin 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.3

Dissolved gas analysis (DGA) method is widely used to detect the incipient fault of power transformers. This paper presents a novel DGA method for power transformer fault diagnosis based on Harris-Hawks-optimization (HHO) algorithm optimized kernel extreme learning machine (KELM). The non-code ratios of the gases are used as the characterizing vector for the KELM model, and the Harris-Hawks-optimization (HHO) algorithm is introduced to optimize the KELM parameters, which promotes the fault diagnostic performance of KELM. Based on dataset collected from IEC TC 10, the fault diagnosis capability of the proposed method is validated by different characterizing vectors and is compared with conventional KELM and other optimized KELM. Moreover, the generalization ability of the proposed method is confirmed by China DGA data. The results demonstrate that the proposed method is superior to other methods and is more effective and stable for power transformer fault diagnosis with high accuracy.

Removal of Pb2+ from the aqueous solution by tartrate intercalated layered double hydroxides

Yanming Shen,Xiaolei Zhao,Xi Zhang,Shifeng Li,Dongbin Liu,Lihui Fan 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.1

Adsorption of Pb2+ ion by a tartrate intercalated MgAl layered double hydroxides (MgAl-TA LDHs) was studied. The adsorption isotherms and kinetics were investigated as a function of various experimental parameters using batch adsorption experiments. The results indicated that the adsorption isotherm was well described by Sips model. The kinetic adsorption data were fitted well to the pseudo-second-order kinetic equation. The adsorption of Pb2+ was controlled mainly by the chemical process combined with intraparticle diffusion. Parameters of adsorption thermodynamic suggested that the interaction of Pb2+ adsorbed by MgAl-TA LDHs adsorbents was thermodynamically spontaneous and endothermic.

LncRNA MALAT1/MiR-145 Adjusts IL-1β-Induced Chondrocytes Viability and Cartilage Matrix Degradation by Regulating ADAMTS5 in Human Osteoarthritis

Chengyao Liu,Shan Ren,Shifeng Zhao,Yandong Wang 연세대학교의과대학 2019 Yonsei medical journal Vol.60 No.11

Purpose: Accumulating evidence suggests that microRNA-145 (miR-145) plays an important role in osteoarthritis (OA), which is achronic progressive joint disease. Long noncoding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) promotesmetastasis in cancers and functions as a sponge for miR-145. However, the role of MALAT1/miR-145 in OA pathogenesishas not yet been elucidated. Materials and Methods: The expression of MALAT1 and miR-145 was examined by quantitative real-time PCR; the interactionbetween miR-145, MALAT1 and a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) 5 was verified by luciferasereporter assay. Correlations among MALAT1, miR-145, and ADAMTS5 were analyzed by Spearman rank analysis. Chondrocytesviability and cartilage extracellular matrix (ECM) degradation were investigated with cell viability assay and Western blottinganalyzing expression of ADAMTS5, collagen type 2 alpha 1 (COL2A1), aggrecan (ACAN), and cartilage oligomeric matrix protein(COMP). Results: MALAT1 was upregulated, and miR-145 was downregulated in OA samples and IL-1β-induced chondrocytes. Mechanically,miR-145 could directly bind to MALAT1 and ADAMTS5. Moreover, miR-145 expression was negatively correlated withMALAT1 and ADAMTS5 expression in OA patients, whereas MALAT1 and ADAMTS5 expression was positively correlated. Functionally,overexpression of MALAT1 inhibited chondrocyte viability and promoted cartilage ECM degradation in IL-1β-inducedchondrocytes. In support thereof, MALAT1 silencing and miR-145 upregulation exerted the opposite effect in IL-1β-inducedchondrocytes. Moreover, the effect of MALAT1 was counteracted by miR-145 upregulation, and ADAMTS5 restoration couldabate miR-145 effects. Conclusion: An MALAT1/miR-145 axis contributes to ECM degradation in IL-1β-induced chondrocytes through targeting ADAMTS5,suggesting that MALAT1/miR-145/ADAMTS5 signaling may underlie human OA pathogenesis.

Microwave heating assisted synthesis of novel SnSe/g-C3N4 composites for effective photocatalytic H2 production

Pengfei Chen,Xiaoquan Dai,Pingxing Xing,Xinyue Zhao,Qingle Zhang,Shifeng Ge,Jianxiao Si,Leihong Zhao,Yiming He 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.80 No.-

Novel SnSe/g-C3N4 photocatalysts were one-step synthesized via a microwave heating assisted process in35 min with SnSe and melamine as precursors. The as-synthesized SnSe/g-C3N4 worked very well in H2evolution via photocatalysis. Under simulated sunlight, the best SnSe/g-C3N4 sample displayed a H2-production velocity of 1064 mmol g 1 h 1, which is 1.8 folds faster than that of neat g-C3N4. Similarpromotion effect was also observed under visible light. To reveal the nature behind the highphotoactivity, a thorough investigation was performed. XRD and XPS experiments proved the binaryconstitution of the composite. DRS experiment demonstrated that the addition of SnSe improved thephotoabsorption performance. N2-adsorption analysis showed that the SnSe/g-C3N4 photocatalystpresented similar surface area as g-C3N4. TEM experiments showed that some bulk SnSe werespontaneously decomposed to nanoparticles andfinely dispersed in g-C3N4 during the microwaveheating process. These SnSe nanoparticles were believed to be the active phase and constructed aheterojunction structure with g-C3N4, resulting in the enhanced charge separation. This conclusion wasconsidered as the key factor leading to the high H2-evolution performance and was further confirmed bythe PL, EIS, and PC experiments. The present work provides a feasible and rapid method for theconstruction of g-C3N4 based photocatalysts.