Fabrication and Interface Structural Behavior of Mg/Al Thickness-Oriented Bonding Sheet via Direct Extrusion

Lei Gao,Feng Li,Ye Wang,Xing Mao Xiao,Peng Da Huo 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.8

Solid-state bonding of heterogeneous materials is one of the effective ways to achieve light weight. An extrusion formingprocess for Mg/Al thickness-oriented bonding sheet was carried out. Due to triaxial compressive stress in the extrusion container,the AZ31 and AA6061 billets were deformed and the bonding and forming of Mg/Al thickness-oriented sheet can berealized by this method. The observation results of the bonding position by using XRD, SEM and EDS showed that: at theforming temperature with 360–420 °C, it had a good bonding interface, and the width of the transition layer increased withthe increase of the forming temperature. The presence of brittle intermetallic compounds in the transition layer indicated thatmetallurgical bonding had occurred at the interface. Considering all factors comprehensively, when the forming temperaturewas 390 °C, the bonding quality was appropriate. Its tensile-shear strength was 42 MPa, the width of the interface transitionlayer was about 10 μm, and the microhardness was about 164.3 HV. This method provided scientific guidance and technicalreserves for green forming of Mg/Al sheets.

Efficient Mucosal Immunization by Mucoadhesive and pH-Sensitive Polymeric Vaccine Delivery System

Lei Xing,Tian-Jiao Zhou,Ya-Tong Fan,Yu-jing He,Tao Pang,조기현,Jinjian Lu,Hu-Lin Jiang,조종수 한국고분자학회 2019 Macromolecular Research Vol.27 No.3

Mucosal surfaces as the largest immune organ of human body cover 400 m2 of the body including the gastrointestinal, urogenital, and respiratory tracts. The local mucosal immunity is an important first line of defense against many pathogens because most pathogens initiate their infection through access to the mucosal region of body. Also, the mucosal vaccines induce mucosal and systemic immunity simultaneously. Therefore, attracted by the advantages of mucosal immunity, researchers keep an eye on the mucoadhesive and pH-sensitive polymeric vaccine delivery system to solve several limitations of mucosal administration, making mucosal immunity receive great interests lately. In this review, we discuss natural polymer- and synthetic polymer-based mucoadhesive and pHsensitive systems used for mucosal vaccine delivery. Also, we cover how to target antigen presenting cells and M cells for the cell specificity. Finally, we conclude the significant progress in mucosal vaccine and the prospect mucosal vaccine research in the future.

Dynamic Path Planning Based on Fuzzy and Behavior Control Idea

Lei Yanmin,Xing Xiaoxue,Feng Zhibin,Guan Xiuli,Du Limin 보안공학연구지원센터 2014 International Journal of Control and Automation Vol.7 No.12

In order to solve dynamic path planning problem of multi-robot systems in unknown dynamic environment, a kind of method based on fuzzy and behavior control idea was proposed in this paper. This method designs two fuzzy controllers, which are danger degree fuzzy controller and velocity fuzzy controller. They took fully into account the position and the velocity of the obstacle and the azimuth of the target. Fuzzy rules were designed based on behavior control idea and which reflected move-to-goal behavior, avoid-obstacle behavior and follow-obstacle behavior. The experimental results show that the proposed method is feasible and valid and is suitable for the dynamic and complicated environment in particularly.

Expression of RUNX2/LAPTM5 in the Induction of MC3T3-e1 Mineralization and Its Possible Relationship with Autophagy

Xing Lei,Li Yanqin,Li Wenhao,Liu Rong,Geng Yuanming,Ma Weiqun,Qiao Yu,Li Jianwen,Lv Yingtao,Fang Ying,Xu Pingping 한국조직공학과 재생의학회 2022 조직공학과 재생의학 Vol.19 No.6

BACKGROUND: The study aims to correlate osteogenesis with autophagy during the mineralization induction of MC3T3-e1 through exploring the expression of runt-related transcription factor 2 (RUNX2)/lysosomal-associated transmembrane protein 5 (LAMPT5). METHODS: The induction of mineralization in MC3T3-e1 was followed by detecting the expressions of osteogenesisrelated indexes such as RUNX2, alkaline phosphatase (ALP), osteocalcin (OCN), and LAPTM5 using RT-qPCR and Western blot from 0 to 14 days. Transmission electron microscope was utilised in visualizing the alterations of autophagosomes, which was followed by immunofluorescence detecting the subcellular localization of autophagy-related index sequestosome 1 (P62) and microtubule-associated protein 1 light 3 (LC3) protein and scrutinising the expression of P62 mRNA and P62 and LC3 proteins. RESULTS: Induction of MC3T3-e1 mineralization demonstrated an increased expression of osteogenesis-related indicators such as RUNX2, ALP, OCN, and LAPTM5 (p\0.05), as evident from the results of RT-qPCR and Western blot. Meanwhile, the expression of autophagosomes increased one day after mineralization induction and then experienced a gradual decline, and enhanced expression of LC3 protein was noted on days 1–2 of mineralization induction but was then followed by a corresponding reduce. In contrast, a continuous increase was reported in the expression of P62 mRNA and protein, respectively (p\0.05). Up- and down-regulating RUNX2/LAPTM5 expression alone confirmed the aforementioned results. CONCLUSION: It was therefore proposed that RUNX2 may be responsible for an early increase and then a gradual decrease in LAPTM5-mediated autophagy through the regulation of its high expression. Meanwhile, increased LAPTM5 expression in osteogenic mineralization presumed that RUNX2/LAPTM5 promoted autophagy and osteogenic expression, which may play a bridging role in the regulation of autophagy and osteogenesis.

Motor Drive Dc Arc Detection Using Autocorrelation Algorithm

Lei Xing,Xin Wu,Charles Lents 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

The demand for electric power in aircrafts is increasing fast. As a result, an elevated voltage is needed for the rising power level, in order to optimize the whole system. This will make the system more vulnerable to arc faults. Therefore, how to detect an arc fault before it causes catastrophic damage is a critical problem. This paper proposes a new arc fault detection method based on autocorrelation algorithm, which can provide reliable arc detection function. Simulation and experimental measurement results will be presented to validate the performance of the detector.

Characterization of SiC/C Nanocomposite Powders Synthesized by Arc-Discharge

Zhou, Lei,Yu, Jie Yi,Gao, Jian,Wang, Dong Xing,Gan, Xiao Rong,Xue, Fang Hong,Huang, Hao,Dong, Xing Long Korean Society of Microscopy 2015 Applied microscopy Vol.45 No.4

In this paper, three carbon sources, i.e., solid graphite, gaseous CH4 and liquid ethanol, and one solid silicon source were employed to synthesize SiC/C nanocomposite powders by arc-discharge plasma. The processing conditions such as the component ratios of raw materials, atmospheric gases, etc. were adjusted for controllable synthesis of the nanopowders. It is indicated that both of solid graphite and silicon can be co-evaporated and reacted to form nanophases of cubic ${\beta}$-SiC with ~50 nm in mean size and a little free graphite; the carbon atoms decomposed from gaseous $CH_4$ favor to combine with the evaporated silicon atoms to form the dominant SiC nanophase; liquid carbon source of ethanol can also be used to harvest the main ${\beta}$-SiC and minor 6H-SiC phases in the assembly of nanoparticles. The as-prepared SiC/C nanocomposite powders were further purified by a heat-treatment in air and their photocatalytic performances were then greatly improved.

친환경 인테리어제품이 적용된 공간디자인 사례연구

양흥뢰(Yang, Xing Lei),김선철(Kim, Sun Chul) 한국디지털디자인협의회 2014 (사)한국디지털디자인협의회 conference Vol.2014 No.5

Characterization and Electrical Conductivity of Carbon-Coated Metallic (Ni, Cu, Sn) Nanocapsules

Wang, Dong Xing,Shah, Asif,Zhou, Lei,Zhang, Xue Feng,Liu, Chun Jing,Huang, Hao,Dong, Xing Long Korean Society of Microscopy 2015 Applied microscopy Vol.45 No.4

Carbon-coated Ni, Cu and Sn nanocapsules were investigated by means of X-ray diffraction (XRD), transmission electron microscopy (TEM) and a four-point probe device. All of these nanocapsules were prepared by an arc-discharge method, in which the bulk metals were evaporated under methane ($CH_4$) atmosphere. Three pure metals (Ni, Cu, Sn) were typically diverse in formation of the carbon encapsulated nanoparticles and their different mechanisms were investigated. It was indicated that a thick carbon layers formed on the surface of Ni(C) nanocapsules, whereas a thin shell of carbon with 1~2 layers covered on Cu(C) nanocapsules, and the Sn(C) nanocapsules was, in fact, a longger multi-walled carbon nanotubes partially-filled with metal Sn. As one typical magnetic/dielectric nanocomposite particles, Ni(C) nanocapsules and its counterpart of oxide-coated Ni(O) nanocapsules were compared in the electrically conductive behaviors for further applications as the electromagnetic materials.

Economic Growth and Environmental Quality : A Case Study from Industrial Sulfur Dioxide Provincial Panel Data in China

Lei, Shi,Lu, Xing Korean Resource Economics Association 2007 자원·환경경제연구 Vol.16 No.3

The Environmental Kuznets Curve Hypothesis postulates an inverted-U shaped relationship between GDP per capita and various pollutants. Pollutants emission increases up to a certain level as income goes up; after that, it decreases. This paper investigates the relationship between industry pollutants taking industrial sulfur dioxide omission as example, and economic growth by using province-panel data set from 1989 to 2004 in 28 provinces of P. R. China. The result shows that the EKC hypothesis may be supported in the case of industrial sulfur dioxide, and the GDP per capital of turning point is about RMB 13,548 (at 1978 price). Except Shanghai, all the provinces GDP per capital in this study are less than RMB 13,548, indicating the amount of industrial sulfur dioxide emission will be increasing in the near future. To realize sustainable development and pollutants abatement, the central and local government should adopt an integrated strategy to protect environment.

Synthesis and Excellent Microwave Absorption Properties of ZnO/Fe3O4/MWCNTs Composites

Lei Wang,Honglong Xing,Zhenfeng Liu,Ziyao Shen,Xiang Sun,Guocai Xu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.12

ZnO nanocrystals were introduced into Fe3O4/MWCNTs composites to improve the impedance matching and electromagnetic (EM) wave attenuation of the system. The as-synthesized ZnO/ Fe3O4/MWCNTs composites were characterized by X-ray diffraction, vibrating sample magnetometer, field-emission scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy. SEM and TEM images showed that Fe3O4 microspheres 100–200 nm in size connected MWCNTs. Analysis of EM parameters revealed that the impedance matching of the ZnO/Fe3O4/MWCNTs composites was considerably improved after ZnO nanocrystals were introduced. The ZnO/Fe3O4/MWCNTs composites exhibited a highly efficient microwave absorption (MA) capacity within the tested frequency range of 2–18 GHz. The optimal reflection loss of EM waves was -38.2 dB at 6.08 GHz with an absorber thickness of 3.5 mm. The excellent MA properties of the composites could be attributed to the improved impedance matching, interfacial polarization, and combined effects of dielectric and magnetic losses.