Electrochemical Behavior of a Vacuum-Brazed 10Ni-WC/NiCrBSi Composite Coating

Zhu Jiawei,Zou Jiasheng,Qiao Yanxin,Wang Yi,Xu Xiangping 한국물리학회 2020 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.76 No.11

In this work, a 10Ni-WC/NiCrBSi composite coating was fabricated on a Q235 substrate by using vacuum brazing. The bonding strength, surface hardness and corrosion behavior of the coating were characterized by using shearing, a Vickers hardness test and an electrochemical measurement. The results showed that the bonding strength was 365.1 MPa and that the surface hardness of the coating reached nearly 2500 HV, which was ten times that of the Q235 substrate. The corrosion trend of the coating was analyzed by electrochemical impedance spectroscopy and potentiodynamic polarization curves. The results showed that the electrochemical system of the coating was a charge-transfer control system with a passive behavior. Combined corrosion micro-morphology and the energy dispersive X-ray spectroscopy (EDS) showed that the 10Ni-WC/NiCrBSi composite coating had superior corrosion resistance, but the pitting corrosion resistance of the coating was poor. In addition, after corrosion, the hard phase particles inside the coating were shown not to fail. The corrosion resistance of the vacuum-cladded 10Ni-WC/NiCrBSi coating was obtained.

MSC p43 required for axonal development in motor neurons.

Zhu, Xiaodong,Liu, Yang,Yin, Yanqing,Shao, Aiyun,Zhang, Bo,Kim, Sunghoon,Zhou, Jiawei National Academy of Sciences 2009 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.106 No.37

<P>Neuron connectivity and correct neural function largely depend on axonal integrity. Neurofilaments (NFs) constitute the main cytoskeletal network maintaining the structural integrity of neurons and exhibit dynamic changes during axonal and dendritic growth. However, the mechanisms underlying axonal development and maintenance remain poorly understood. Here, we identify that multisynthetase complex p43 (MSC p43) is essential for NF assembly and axon maintenance. The MSC p43 protein was predominantly expressed in central neurons and interacted with NF light subunit in vivo. Mice lacking MSC p43 exhibited axon degeneration in motor neurons, defective neuromuscular junctions, muscular atrophy, and motor dysfunction. Furthermore, MSC p43 depletion in mice caused disorganization of the axonal NF network. Mechanistically, MSC p43 is required for maintaining normal phosphorylation levels of NFs. Thus, MSC p43 is indispensable in maintaining axonal integrity. Its dysfunction may underlie the NF disorganization and axon degeneration associated with motor neuron degenerative diseases.</P>

Optimization Design of the Decentralized Multi-Vehicle Cooperative Controller for Freeway Ramp Entrance

Wang Jiawei,Ma Fangwu,Yu Yang,Zhu Sheng,Gelbal Sukru Yaren,Aksun-Guvenc Bilin,Guvenc Levent 한국자동차공학회 2021 International journal of automotive technology Vol.22 No.3

This research presents a multi-vehicle control strategy combining the merging control and platoon control to deal with the merging scenario in the freeway ramp entrance. In the merging controller, a selection algorithm is presented firstly to determine the merging sequence based on the initial states of the vehicles in the cooperative area. Subsequently, the optimized longitudinal trajectory of the facilitating vehicle and on-ramp vehicle is addressed by solving the Hamiltonian function. As for the platoon controller, string stability is analyzed to attenuate the impact of merging on the mainline traffic, considering the influence of communication time delay. Smooth mode switching is achieved by introducing the tracking policy of platoon controller to determine the terminal states of the facilitating vehicle. The proposed strategy is simulated at two typical merging scenarios, where two on-ramp vehicles attempt to cut into a six-vehicular platoon, to validate its feasibility and advantage.

Broadband Spectrum Sensing of Distributed Modulated Wideband Converter Based on Markov Random Field

Zhi Li,Jiawei Zhu,Ziyong Xu,Wei Hua 한국전자통신연구원 2018 ETRI Journal Vol.40 No.2

The Distributed Modulated Wideband Converter (DMWC) is a networking system developed from the Modulated Wideband Converter, which converts all sampling channels into sensing nodes with number variables to implement signal undersampling. When the number of sparse subbands changes, the number of nodes can be adjusted flexibly to improve the reconstruction rate. Owing to the different attenuations of distributed nodes in different locations, it is worthwhile to find out how to select the optimal sensing node as the sampling channel. This paper proposes the spectrum sensing of DMWC based on a Markov random field (MRF) to select the ideal node, which is compared to the image edge segmentation. The attenuation of the candidate nodes is estimated based on the attenuation of the neighboring nodes that have participated in the DMWC system. Theoretical analysis and numerical simulations show that neighboring attenuation plays an important role in determining the node selection, and selecting the node using MRF can avoid serious transmission attenuation. Furthermore, DMWC can greatly improve recovery performance by using a Markov random field compared with random selection.

Design and analysis of mechanical flux‑weakening device of axial flux permanent magnet machines

Shaopeng Wang,Jiawei Lu,Bin Li,Chengcheng Liu,Youhua Wang,Gang Lei,Youguang Guo,Jianguo Zhu 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.4

Due to the low inductance of an axial flux permanent magnet machine (AFPMM), the constant power speed regulation range is small. A new mechanical flux-weakening method for single-rotor single-stator AFPMMs is proposed in this paper. By installing a mechanical flux-weakening device on one side of the stator and rotating it certain angle, the speed regulation of the flux-weakening can be realized. The device is simple in structure, easy to operate, and can be operated in the process of machine operation. The validity of the device is verified by applying it to a machine. Finite-element software is used to calculate and analyze the performances of two machines with the device.

Fabrication of novel self-healable ultraslippery surface for preventing marine microbiologically influenced corrosion

Hao Jiang,Wenhuan Wang,Jiawei Li,Liyang Zhu,Dun Zhang,Peng Wang,Guoqing Wang 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.109 No.-

Slippery liquid-infused porous surfaces (SLIPS) have attracted wide attention in the field of marine anticorrosion. However, the stability problem severely restricts the broad applications of SLIPS. Herein, wefabricated a polyurethane-based ultraslippery surface with lubricant self-replenishing and matrix selfhealingproperties owing to the huge amount of dynamic hydrogen-bond. Besides, the bacteria culturetest and electrochemical analysis results indicate the prepared surface possesses superior properties inthe protection of microbiologically influenced corrosion (MIC). This paper offers an efficient strategy tosolve stability problem of SLIPS, and the as-obtained self-healable ultraslippery surface can be used asa promising material in mitigating MIC.

The Stability, and Efficacy Against Penicillin-Resistant Enterococcus faecium, of the Plectasin Peptide Efficiently Produced by Escherichia coli

( Xin Chen ),( Yaoan Wen ),( Ling Li ),( Jiawei Shi ),( Zhe Zhu ),( Yuwen Luo ),( Yun Li ),( Rui Chen ) 한국미생물 · 생명공학회 2015 Journal of microbiology and biotechnology Vol.25 No.7

Plectasin, the first defensin extracted from a fungus (the saprophytic ascomycetePseudoplectania nigrella), is attractive as a prospective antimicrobial agent. The purpose of this study was to establish a bacterium-based production system and evaluate the antimicrobial activity of the resulting plectasin. A gene encoding plectasin, with the codon preference ofEscherichia coli, was optimized based on its amino acid sequence, synthesized using genesplicing with overlap extension PCR, and inserted into the expression vector pGEX-4T-1. The fusion protein was expressed in the soluble fraction of E. coli and purified using glutathione Stransferaseaffinity chromatography. Plectasin was cleaved from the fusion protein with thrombin and purified by ultrafiltration. The purified plectasin showed strong, concentrationdependent antimicrobial activity against gram-positive bacteria, including antibiotic-resistant bacteria, especially penicillin-resistant Enterococcus faecium. This antimicrobial activity wasequal to chemically synthesized plectasin and was maintained over a wide range of pH and temperatures. This soluble recombinant expression system in E. coli is effective for producing plectasin at a relatively lower cost, and higher purity and efficiency than prior systems, and might provide a foundation for developing a large-scale production system. Overall, plectasin shows potential as a novel, high-performance, and safe antibiotic for the treatment of refractory diseases caused by drug-resistant bacterial strains.