Effect of Li Content on the Surface Film Formed on the Binary Mg–Li Alloys in NaCl Solution

Chuanqiang Li,Dahui Liang,Yejia Lin,Yong Dong,Binqing Shi,Changjian Yan,Zhengrong Zhang 대한금속·재료학회 2024 METALS AND MATERIALS International Vol.30 No.1

The surface film formed on the Mg–Li alloys with different Li content in 0.1 M NaCl solution were investigated via electrochemicaltesting, morphologies observation and chemical composition analysis in this work. The results revealed that thesurface film of Mg–14Li alloy (L14: body centred cubic (BCC)) possessed higher electrical resistivity and remained a highertolerating over-potential (0.1 V vs. open circuit potential) than those of Mg–4Li (L4: hexagonal closed-packed (HCP)) andMg–7.5Li (L7: HCP+BCC), resulting in a better corrosion performance. After 24 h immersion in NaCl solution, the wholesurface film of L14 remained undamaged and displayed weave-like and dense characteristic, while both L4 and L7 present aseverely damaged film. The cross-sectional details illustrated typical two layers of surface film formed on L14 with the outerlayer of ~ 1.5 μm and inner layer of ~ 2.5 μm in thickness, whilst only one layer of film with less than 2.5 μm in thicknesswas observed on L4 and L7. At last, combining analysis of X-ray diffraction, energy dispersive X-ray spectrometry, X-rayphotoelectron spectroscopy and transmission electron microscope confirmed the composition of outer layer of surface filmon the L14 contains much more Mg(OH)2 and Li-containing compounds, and the porous Mg(OH)2 film can be sealed by theLi-containing compounds, which is very different the single Mg(OH)2 film on the traditional magnesium and L4/L7 alloys. As a result, the best protective function of the surface film on the L14 alloy contribute to its high corrosion resistance.

Synthesis of full concentration gradient cathode studied by high energy X-ray diffraction

Li, Yan,Xu, Rui,Ren, Yang,Lu, Jun,Wu, Huiming,Wang, Lifen,Miller, Dean J.,Sun, Yang-Kook,Amine, Khalil,Chen, Zonghai Elsevier 2016 Nano energy Vol.19 No.-

<P><B>Abstract</B></P> <P>Nickel-rich metal oxides have been widely pursued as promising cathode materials for high energy-density lithium-ion batteries. Nickel-rich lithium transition metal oxides can deliver a high specific capacity during cycling, but can react with non-aqueous electrolytes. In this work, we have employed a full concentration gradient (FCG) design to provide a nickel-rich core to deliver high capacity and a manganese-rich outer layer to provide enhanced stability and cycle life. <I>In situ</I> high-energy X-ray diffraction was utilized to study the structural evolution of oxides during the solid-state synthesis of FCG lithium transition metal oxide with a nominal composition of LiNi<SUB>0.6</SUB>Mn<SUB>0.2</SUB>Co<SUB>0.2</SUB>O<SUB>2</SUB>. We found that both the pre-heating step and the sintering temperature were critical in controlling phase separation of the transition metal oxides and minimizing the content of Li<SUB>2</SUB>CO<SUB>3</SUB> and NiO, both of which deteriorate the electrochemical performance of the final material. The insights revealed in this work can also be utilized for the design of other nickel-rich high energy-density cathode materials.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Solid-state synthesis of FCG cathode is investigated by <I>in situ</I> XRD. </LI> <LI> Covariance analysis and Rietveld refinement are used to analyze the HEXRD data. </LI> <LI> Synthetic optimization of FCG cathode with excellent electrochemical performance. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Benefit from the covariance analysis and Rietveld refinement of <I>in situ</I> HEXRD data during the solid state synthesis, we can optimized the solid state synthesis conditions in a short time. And the full concentration gradient cathode composites (nickel-rich core and manganese-rich outer layer) with excellent electrochemical performance are obtained.</P> <P>[DISPLAY OMISSION]</P>

Correlation between DNA methylation and Thymic Stromal Lymphopoietin expression in asthmatic airway epithelial cells

Yan‑Li Li,Xi‑Qian Xing,Yi Xiao,Yan‑Hong Liu,Yu‑Shan Zhou,Min Zhuang,Chao‑Qian Li 한국유전학회 2020 Genes & Genomics Vol.42 No.12

Background: The overexpression of TSLP and DNA methylation in asthma were both risk factors the relationship was not clear. Objective: This study aimed to investigate the relationship between methylation status of TSLP promoter and mRNA/protein expression in asthmatic airway epithelial cells. Methods: Human bronchial epithelial cells were cultured in vitro and divided into: Control group, treated with PBS, model group, sensitized with LPS (10 μg/mL) for 12 h (37 °C, 5% CO2). Other groups were cultured with the pCMV3 plasmid (M + NC/pCMV), pGPH1 plasmid (M + NC/pGPH), DNMT1/pCMV3 plasmid (M + DNMT1/pCMV), and DNMT1/pGPH1 plasmid (M + DNMT1/pGPH) for 48 h. The expression of DNA methyltransferase 1 and TSLP were measured using real-time PCR and western blotting. Results: Compared with the control group, TSLP mRNA (1.00 ± 0.00 vs. 2.82 ± 0.81 vs. 1, P < 0.001) and protein (1.07 ± 0.04 vs. 1.46 ± 0.11, P < 0.01) were significantly greater, and the methylation of promoter was lower (92.75 ± 1.26 vs. 58.57 ± 3.34, P < 0.05) in the model group. Compared with the model group, TSLP mRNA (2.82 ± 0.81 vs. 1.17 ± 0.10, P < 0.001) decreased, but TSLP promoter methylation increased (58.57 ± 3.34 vs. 92.58 ± 7.30, P < 0.05) in M + DNMT1/pCMV. TSLP mRNA and protein were higher (2.82 ± 0.81 vs. 5.32 ± 0.21, P < 0.001; 1.46 ± 0.11 vs. 1.94 ± 0.11, respectively, P < 0.01), TSLP promoter methylation was lower (58.57 ± 3.34 vs. 33.57 ± 4.29, P < 0.05) in M + DNMT1/pGPH. Conclusions: Overexpression of TSLP in asthmatic airway epithelial cells may be regulated by DNA demethylation.

Pressure and temperature dependence of the decomposition pathway of LiBH₄

Yan, Yigang,Remhof, Arndt,Hwang, Son-Jong,Li, Hai-Wen,Mauron, Philippe,Orimo, Shin-ichi,Zü,ttel, Andreas The Royal Society of Chemistry 2012 Physical chemistry chemical physics Vol.14 No.18

<P>The decomposition pathway is crucial for the applicability of LiBH<SUB>4</SUB> as a hydrogen storage material. We discuss and compare the different decomposition pathways of LiBH<SUB>4</SUB> according to the thermodynamic parameters and show the experimental ways to realize them. Two pathways, <I>i.e.</I> the direct decomposition into boron and the decomposition <I>via</I> Li<SUB>2</SUB>B<SUB>12</SUB>H<SUB>12</SUB>, were realized under appropriate conditions, respectively. By applying a H<SUB>2</SUB> pressure of 50 bar at 873 K or 10 bar at 700 K, LiBH<SUB>4</SUB> is forced to decompose into Li<SUB>2</SUB>B<SUB>12</SUB>H<SUB>12</SUB>. In a lower pressure range of 0.1 to 10 bar at 873 K and 800 K, the concurrence of both decomposition pathways is observed. Raman spectroscopy and <SUP>11</SUP>B MAS NMR measurements confirm the formation of an intermediate Li<SUB>2</SUB>B<SUB>12</SUB>H<SUB>12</SUB> phase (mostly Li<SUB>2</SUB>B<SUB>12</SUB>H<SUB>12</SUB> adducts, such as dimers or trimers) and amorphous boron.</P> <P>Graphic Abstract</P><P>The thermodynamic properties of LiBH<SUB>4</SUB> and its possible decomposition products and intermediates allow flexibility in selection of the decomposition pathway by tuning the external parameters such as pressure and temperature. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2cp40131b'> </P>

Improved lithium storage performance of CeO2-decorated SrLi2Ti6O14 material as an anode for Li-ion battery

Ying Li,Hong-Yan Liu,Ling-Na Shi,Yan-Rong Zhu,Ting-Feng Yi 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.101 No.-

In this work, the CeO2-decorated SrLi2Ti6O14 anode was successfully prepared through a solid-state process. The space-charge effect induced by the internal adsorption of ions on the CeO2 surface can easilyresult in a formation of an excellent conductive interfacial layer between CeO2 and SrLi2Ti6O14. The goodelectrical contact between CeO2 and SrLi2Ti6O14 offers more active sites for the electrolyte storage andredox reaction, and promotes the intercalation/deintercalation of lithium ions, and thus improves therate performance and cycle stability. Due to its unique structure and composition, the CeO2-decoratedSrLi2Ti6O14 composites exhibit high reversible capacities, good cycle performance and outstanding rateperformance. Especially, the CeO2 (5 wt%)-decorated SrLi2Ti6O14 anode shows the most excellent electrochemicalperformance, which delivers a large charge capacity of 121.3 mAh g 1 and a capacity retentionof 94.48% after 100 cycles at 0.5 A g 1. However, the corresponding charge capacity and capacity retentionof pristine SrLi2Ti6O14 are 100.5 mAh g 1 and 86.77%, respectively. The CeO2(5 wt%)-decoratedSrLi2Ti6O14 with enhanced rate capacity, cycle stability and structural stability is a potential electrodematerial candidate for Li-ion battery.

A Mild Strategy to Strengthen Three Dimensional Graphene Aerogel for Supporting Sulfur as a Free‐standing Cathode in Lithium–Sulfur Batteries

Yinglin Yan,Haichao Qin,Yiqi Wei,Rong Yang,Yunhua Xu,Liping Chen,Qiaole Li,Mangmang Shi 대한화학회 2018 Bulletin of the Korean Chemical Society Vol.39 No.5

Recently, three dimensional graphene aerogel (3DGA) supported sulfur microparticles was used as a cathode material for lithium?sulfur batteries, which was considered as one of the most promising next generation rechargeable batteries due to its ultra?high theoretical specific capacity (1675 mAh/g). However, the mechanical strength of 3DGA remains an issue for further application. Herein, a strengthened 3DGA (S3DGA) was achieved by soaking in a low concentration ammonia solution at a relative low temperature. Then the S3DGA loaded sulfur (S3DGA?S) was cut into a round piece and directly used as a cathode without additional binders or conductive additives in Li?S batteries. The mechanical strength, microstructure, and electrochemical properties were investigated by compare with a 3DGA prepared without strengthen. The S3DGA?S presented good mechanical strength, excellent capacity retention, and lower electrochemical impedance.

Intragranular and Intergranular Crack Propagation in Nanocrystalline Ni Under Single-Cycle Mode I Loading

Yan Feng,Jie Li,Xinhua Yang 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.7

As the first step to study the fatigue crack propagation, the molecular simulations were performed to investigate theopening, propagation and closure behaviors of intragranular and intergranular cracks in nanocrystalline Ni under single-cyclemode I loading. The atomic crack angle was proposed to characterize the crack-tip blunting and sharpening quantitatively. There are obvious different mechanisms between intragranular and intergranular crack propagation. Intragranular crack propagationcould be induced by stacking faults and can change its direction very easily, but the intergranular crack perpendicularto the loading direction would propagate along the grain boundary and encounter strong resistance at the triple junction. New cracks could form in the grain boundaries ahead of the original crack. Different from the traditional understanding forintragranular and intergranular cracks, however, the dislocation density increases even in the unloading process and the cracktip is possibly sharpened temporarily during loading.

Identification and characterization of heat shock proteins in a parasitic wasp Chouioia cuneae (Hymenoptera: Eulophidae)

Li‐Na Pan,Feng-ZhuWANG,Xin-Yue ZHANG,Yan-Ni ZHAO,Geng-Ping ZHU,Min LI 한국곤충학회 2018 Entomological Research Vol.48 No.3

Heat shock proteins (HSPs) are known to be induced in response to various stress factors. Although HSPs have been studied in a number of insects, not much is known about HSPs in the natural enemies of insects, especially parasitoids. In this study, we identified and characterized five full‐length HSP genes (Cchsp40, Cchsp60, Cchsp70, Cchsp83, and Cchsp90) from an endoparasitic chalcid wasp, Chouioia cunea, which parasitizes the fall webworm, Hyphantria cunea pupae, a worldwide pest. The expression of Cchsps in response to temperature, pesticide stresses and UV radiation were also investigated by quantitative real‐time polymerase chain reaction (RT‐qPCR). The results showed that all five Cchsps were induced in response to hot and cold temperatures. Four pesticides induced the abundant expression of Cchsp70, Cchsp83 and Cchsp90 while ultraviolet radiation up‐regulated Cchsp40, Cchsp70, Cchsp83 and Cchsp90. These results indicate the different transcriptional profiles of the five different Cchsps in response to various abiotic stresses. The findings of this study provide insights into the response of C. cunea to abiotic stresses and insight into the use of this parasitoid in biological control strategies.

거주 경험과 상호작용 정도에 따른 한국어 사회문화적 함축 이해 -중국인 고급 한국어 학습자를 대상으로-

이암 ( Li¸ Yan ),이지현 ( Lee¸ Jihyun ) 국제한국어교육학회 2020 한국어 교육 Vol.31 No.3

This study aims to analyze how advanced Chinese Korean learners understand social and cultural implicatures based on their residential experience in Korea and the intensity of interaction. Research questions for this paper are as follows: (1) Which of the social and cultural domains is difficult to understand? (2) Does the residential experience in Korea and intensity of interaction impact their understanding of implicatures? If so, which is the most influential factor? According to the results of the experiment, Chinese learners did not have high scores in all implications; in particular, they had the lowest understanding of implicatures of the political realm. In addition, both the intensity of interaction and residential experience influenced the understanding of implications, and therefore, the latter has become the biggest factor in understanding sociocultural implicatures. (Dalian University of Foreign Languages Ewha Womans University)

Nodule Rich Protein 2 modulates nodule number in Medicago truncatula

Junhui Yan,Xinwei Yang,Yawen Wang,Liangliang Yu,Li Luo 한국식물생명공학회 2021 Plant biotechnology reports Vol.15 No.1

Symbiotic nitrogen fxation is beneft to sustainable agriculture and global nitrogen cycle. Many small peptides were identifed as regulators involving in the interaction between rhizobia and legume. Here we reported Nodule Rich Protein 2 (MtNRP2) encoding a small peptide in Medicago truncatula, belonged to a group of nodule rich protein restricted in legume species. MtNRP2 expressed highly in root nodule and its promoter was active during the initiation and development of root nodule and lateral root. To investigate the function of MtNRP2 in nodulation, we generated MtNRP2-overexpression and MtNRP2- knockdown transgenic Medicago. MtNRP2-overexpression transgenic lines performed normal nodulation phenotype compared with vector control. However, in the MtNRP2-RNAi transgenic plants, the decrease of MtNRP2 expression lead to the increase of infection threads number (7 day post inoculation) and nodules number (3 week post inoculation); meanwhile, the expression of MtRGF3 and MtPUB1 was inhibited. These results suggested that MtNRP2 negatively regulated nodulation in Medicago truncatula.