Construction of High Strain Rate Loading Constitutive Model and Failure Model and Prediction of Forming Limit for LA103Z Magnesium Alloy

Hailiang Yang,Xiao Wang,Peng Ni,Zhewen Li,Huixia Liu 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.8

In order to use numerical simulation to reveal the formability of magnesium–lithium alloys and other light alloys under highstrain rate, it is crucial to construct a constitutive model and a forming limit diagram (FLD) of LA103Z alloy that was formedby laser shock at high strain rate. In this study, three different uniaxial tensile experiments on the ultralight alloy materialLA103Z magnesium alloy were conducted, the mechanical behavior of the material with sensitivity to high strain rate wasstudied, and a Johnson–Cook (JC) constitutive model sensitive to high strain rates and suitable for laser shock forming wasproposed. At the same time, the constitutive parameters and failure parameters of the modified JC model of LA103Z magnesiumalloy were obtained through three different uniaxial tensile experiments. On the basis of the relationship betweentensile loading and stress–strain of LA103Z magnesium alloy, the experiments demonstrated the precision of the modified JCconstitutive model. A modified constitutive model was then developed by using the user material subroutine VUMAT, andthen it was applied to ABAQUS. Finally, the formability of the material was simulated, and the FLD of LA103Z magnesiumalloy material in laser shock forming was predicted. This study provides guidance on the actual production and applicationof LA103Z magnesium alloys.

Mechanical Properties and Strengthening Mechanism of Aluminum Matrix Composites Reinforced by High-entropy Alloy Particles

Kaiguang Luo,Shilei Liu,Hanqing Xiong,Yun Zhang,Charlie Kong,Hailiang Yu 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.11

1 − 6 wt% Al0.5CoCrFeNihigh-entropy alloy particles (HEAp)/AA1050 aluminum matrix composites (AMCs) were preparedby stir casting process. The effect of HEAp mass fractions on microstructure and mechanical properties of the AMCswas studied. The results showed that with the increase in HEAp, the grains were obviously refined, and the ultimate tensilestrength (UTS) was gradually increased. The AA1050 − 3 wt% HEAp AMCs had the optimum mechanical properties. ItsUTS was 115 MPa and its elongation was 32.1%. The fracture mechanism of composites changed from ductile fracture toquasi-cleavage fracture with more HEAp. A theoretical model for predicting the yield strength of composites was established. The theoretical values were in good agreement with experimental results, and the average error between theoreticaland experimental values was 4.2%.

Exact Error Rate of Dual-Channel Receiver with Remote Antenna Unit Selection in Multicell Networks

( Qing Wang ),( Ju Liu ),( Lina Zheng ),( Hailiang Xiong ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.8

The error rate performance of circularly distributed antenna system is studied over Nakagami-m fading channels, where a dual-channel receiver is employed for the quadrature phase shift keying signals detection. To mitigate the Co-Channel Interference (CCI) caused by the adjacent cells and to save the transmit power, this work presents remote antenna unit selection transmission based on the best channel quality and the maximized path-loss, respectively. The commonly used Gaussian and Q-function approximation method in which the CCI and the noise are assumed to be Gaussian distributed fails to depict the precise system performance according to the central limit theory. To this end, this work treats the CCI as a random variable with random variance. Since the in-phase and the quadrature components of the CCI are correlated over Nakagami-m fading channels, the dependency between the in-phase and the quadrature components is also considered for the error rate analysis. For the special case of Rayleigh fading in which the dependency between the in-phase and the quadrature components can be ignored, the closed-form error rate expressions are derived. Numerical results validate the accuracy of the theoretical analysis, and a comparison among different transmission schemes is also performed.

WS2/CoSe2 heterostructure: A designed structure as catalysts for enhanced hydrogen evolution performance

Sajjad Hussain,Kamran Akbar,Dhanasekaran Vikraman,Hailiang Liu,천승현,정종완 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.65 No.-

The development of hydrogen-evolving catalysts based on transition metal dichalchogenides (TMDs) is receiving a great attention for practical application of water-splitting devices and fuel cells due to their high electrocatalytic activity. Herein, we synthesized tungsten disulfide (WS2)/cobalt diselenide (CoSe2) hybrid catalyst for hydrogen evolution reaction (HER). CoSe2 films were first deposited via electrodeposition of Co and followed by selenization process. And, the surface of the synthesized CoSe2 films was covered with WS2 via combined process of sputtering and sulfurization. In acidic media, the WS2/CoSe2 heterostructure catalyst exhibited fast hydrogen evolution kinetics of onset potential and Tafel slope were at 95 mV and 44 mV decade−1, respectively with the excellent electrocatalytic stability over 20 h. WS2/CoSe2 heterostructure electrode demonstrates an excellent HER activity and long-term stability owing to their abundant active edge sites, and the strong chemical and electronic coupling between the CoSe2 and WS2.

WS₂/CoSe₂ heterostructure: A designed structure as catalysts for enhanced hydrogen evolution performance

Hussain, Sajjad,Akbar, Kamran,Vikraman, Dhanasekaran,Liu, Hailiang,Chun, Seung-Hyun,Jung, Jongwan THE KOREAN SOCIETY OF INDUSTRIAL AND ENGINEERING 2018 JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY -S Vol.65 No.-

<P><B>Abstract</B></P> <P>The development of hydrogen-evolving catalysts based on transition metal dichalchogenides (TMDs) is receiving a great attention for practical application of water-splitting devices and fuel cells due to their high electrocatalytic activity. Herein, we synthesized tungsten disulfide (WS<SUB>2</SUB>)/cobalt diselenide (CoSe<SUB>2</SUB>) hybrid catalyst for hydrogen evolution reaction (HER). CoSe<SUB>2</SUB> films were first deposited via electrodeposition of Co and followed by selenization process. And, the surface of the synthesized CoSe<SUB>2</SUB> films was covered with WS<SUB>2</SUB> via combined process of sputtering and sulfurization. In acidic media, the WS<SUB>2</SUB>/CoSe<SUB>2</SUB> heterostructure catalyst exhibited fast hydrogen evolution kinetics of onset potential and Tafel slope were at 95mV and 44mVdecade<SUP>−1</SUP>, respectively with the excellent electrocatalytic stability over 20h. WS<SUB>2</SUB>/CoSe<SUB>2</SUB> heterostructure electrode demonstrates an excellent HER activity and long-term stability owing to their abundant active edge sites, and the strong chemical and electronic coupling between the CoSe<SUB>2</SUB> and WS<SUB>2</SUB>.</P> <P><B>Graphical abstract</B></P> <P>WS<SUB>2</SUB>/CoSe<SUB>2</SUB> hybrid structure was implemented to enhance HER electrocatalytic activity. The WS<SUB>2</SUB>/CoSe<SUB>2</SUB> catalyst exhibited low overpotentials of 95mV (@1mAcm<SUP>−2</SUP>) and 160mV (@ 10mAcm<SUP>−2</SUP>), a high exchange current density of ∼1.0×10<SUP>−2</SUP> mAcm<SUP>−2</SUP>, and a small Tafel slope of 44mVdecade<SUP>−1</SUP>. In addition, WS<SUB>2</SUB>/CoSe<SUB>2</SUB> hybrid electrode was stable over 20h of sustained hydrogen production in 0.5M H<SUB>2</SUB>SO<SUB>4</SUB> acidic medium.</P> <P>[DISPLAY OMISSION]</P>

High Performance MoSe₂/Mo Counter Electrodes Based- Dye-Sensitized Solar Cells

Hussain, Sajjad,Patil, Supriya A.,Vikraman, Dhanasekaran,Liu, Hailiang,Kim, Hak-Sung,Jung, Jongwan The Electrochemical Society 2017 Journal of the Electrochemical Society Vol.164 No.2

<P>In the present study, multilayer MoSe2/Mo nanostructures fabricated by surface selenization of Mo-coated glass substrates using magnetron sputtering, was proposed as a counter electrode (CE) catalyst in dye-sensitized solar cells (DSSCs) to speed up the reduction of triiodide I-3(-) to iodide I-. The extensive cyclic voltammograms (CV) and Tafel curve analysis indicated that the current density of the optimized MoSe2/Mo CE was higher than Pt CEs due to the fast reduction species. Furthermore, the peak current densities of theMoSe(2)/Mo CE showed little degradation after consecutive 100 CV cycles, suggesting high electrochemical stability of the MoSe2/Mo CE. In addition, MoSe2/Mo CE exhibited lower charge-transfer resistance than Pt CEs. Finally, the DSSC assembled with the MoSe2/Mo CE showed a high power conversion efficiency of 9.57% under illumination of 100 mW.cm(-2) (DSSC with Pt CE: 9.15%). (C) 2017 The Electrochemical Society. All rights reserved.</P>

Erythropoietin-Modified Mesenchymal Stem Cells Enhance Anti-fibrosis Efficacy in Mouse Liver Fibrosis Model

Wang Xianyao,Wang Huizhen,Lu Junhou,Feng Zhanhui,Liu Zhongshan,Song Hailiang,Wang Heng,Zhou Yanhua,Xu Jianwei 한국조직공학과 재생의학회 2020 조직공학과 재생의학 Vol.17 No.5

BACKGROUND: Mesenchymal stem cell (MSC)-based cell transplantation is an effective means of treating chronic liver injury, fibrosis and end-stage liver disease. However, extensive studies have found that only a small number of transplanted cells migrate to the site of injury or lesion, and repair efficacy is very limited. METHODS: Bone marrow-derived MSCs (BM-MSCs) were generated that overexpressed the erythropoietin (EPO) gene using a lentivirus. Cell Counting Kit-8 was used to detect the viability of BM-MSCs after overexpressing EPO. Cell migration and apoptosis were verified using Boyden chamber and flow cytometry, respectively. Finally, the anti-fibrosis efficacy of EPO-MSCs was evaluated in vivo using immunohistochemical analysis. RESULTS: EPO overexpression promoted cell viability and migration of BM-MSCs without inducing apoptosis, and EPO-MSC treatment significantly alleviated liver fibrosis in a carbon tetrachloride (CCl4) induced mouse liver fibrosis model. CONCLUSION: EPO-MSCs enhance anti-fibrotic efficacy, with higher cell viability and stronger migration ability compared with treatment with BM-MSCs only. These findings support improving the efficiency of MSCs transplantation as a potential therapeutic strategy for liver fibrosis.

Black Phosphorus-IGZO van der Waals Diode with Low-Resistivity Metal Contacts

Dastgeer, Ghulam,Khan, Muhammad Farooq,Cha, Janghwan,Afzal, Amir Muhammad,Min, Keun Hong,Ko, Byung Min,Liu, Hailiang,Hong, Suklyun,Eom, Jonghwa American Chemical Society 2019 ACS APPLIED MATERIALS & INTERFACES Vol.11 No.11

<P>There have been a few studies of heterojunctions composed of two-dimensional transition-metal dichalcogenides (TMDs) and an oxide layer, but such studies of high-performance electric and optoelectronic devices are essential. Such heterojunctions with low-resistivity metal contacts are needed by the electronics industry to fabricate efficient diodes and photovoltaic devices. Here, a van der Waals heterojunction composed of p-type black phosphorus (p-BP) and n-type indium-gallium-zinc oxide (n-IGZO) films with low-resistivity metal contacts is reported, and it demonstrates high rectification. The low off-state leakage current in the thick IGZO film accounts for the high rectification ratio in a sharp interface of p-BP/n-IGZO devices. For electrostatic gate control, an ionic liquid is introduced to achieve a high rectification ratio of 9.1 × 10<SUP>4</SUP>. The photovoltaic measurements of p-BP/n-IGZO show fast rise and decay times, significant open-circuit voltage and short-circuit current, and a high photoresponsivity of 418 mA/W with a substantial external quantum efficiency of 12.1%. The electric and optoelectronic characteristics of TMDs/oxide layer van der Waals heterojunctions are attractive for industrial applications in the near future.</P> [FIG OMISSION]</BR>

Expression profiling of the mitogen-activated protein kinase gene family reveals their diverse response pattern in two different salt-tolerant Glycyrrhiza species

Cao Aiping,Gao Ling,Wang Fei,Tong Xuechen,Xie Shuangquan,Chen Xifeng,Lu Tianxin,Shen Haitao,Liu Hailiang,Jin Xiang,Li Hongbin 한국유전학회 2022 Genes & Genomics Vol.44 No.7

Background: Mitogen-activated protein kinases (MPKs) play important role in response to environmental stress as crucial signal receptors or sensors. Our previous study indicated that salt stress acts as a positive factor to stimulate the production of pharmacodynamic metabolites in the medicinal plant Glycyrrhiza uralensis. Currently, little is known about the MPK gene family and their functions in the medicinal plant G. uralensis. Objective: Identification, comprehensive bioinformatic analysis, expression profiling, and response pattern under salt stress of the G. uralensis GuMPK gene family. Methods: Genome-wide investigation and expression profiling of the MPK gene family in G. uralensis, and their phylogenetic relationships, evolutionary characteristics, gene structure, motif distribution, promoter cis-acting element, and expression pattern under salt stress in two different salt-tolerant Glycyrrhiza species were performed. Results: A total of 20 G. uralensis GuMPK genes were identified and categorized into five groups, and had conserved gene structure and motif distribution. Expression profiling of GuMPK genes suggested their potentially diverse functions in plant growth and in response to phytohormones and environmental stress, particularly GuMPK1, 2, 5, and 10 as key components for G. uralensis in response to abiotic stress. Further expression analysis under NaCl treatment in two different salt-tolerant Glycyrrhiza species displayed the MPKs' different response patterns, emphasizing the role of MPK2, 5, 7, and 16 as potentially crucial genes for Glycyrrhiza to respond to salt stress. Conclusion: Our results provide a genome-wide identification and expression profiling of MPK gene family in G. uralensis, and establish the foundation for screening key responsive genes and understanding the potential function and regulatory mechanism of GuMPKs in salt responsiveness.