Two-grid methods for semi-linear elliptic interface problems by immersed finite element methods
作者：
Wang, Yang;Chen, Yanping* ;Huang, Yunqing;Liu, Ying
期刊：
应用数学和力学：英文版 ,2019年40(11):1657-1676 ISSN：0253-4827
通讯作者：
Chen, Yanping
作者机构：
[Wang, Yang; Liu, Ying; Huang, Yunqing] Xiangtan Univ, Sch Math & Computat Sci, Xiangtan 411105, Hunan, Peoples R China.;[Chen, Yanping] South China Normal Univ, Sch Math Sci, Guangzhou 510631, Guangdong, Peoples R China.;[Liu, Ying] Hunan Agr Univ, Coll Sci, Changsha 410128, Hunan, Peoples R China.
通讯机构：
[Chen, Yanping] S;South China Normal Univ, Sch Math Sci, Guangzhou 510631, Guangdong, Peoples R China.
关键词：
two-grid method;interface problem;finite element method;immersed interface
摘要：
In this paper, two-grid immersed finite element (IFE) algorithms are proposed and analyzed for semi-linear interface problems with discontinuous diffusion coefficients in two dimension. Because of the advantages of finite element (FE) formulation and the simple structure of Cartesian grids, the IFE discretization is used in this paper. Two-grid schemes are formulated to linearize the FE equations. It is theoretically and numerically illustrated that the coarse space can be selected as coarse as H = O(h1/4) (or H = O(h1/8)), and the asymptotically optimal approximation can be achieved as the nonlinear schemes. As a result, we can settle a great majority of nonlinear equations as easy as linearized problems. In order to estimate the present two-grid algorithms, we derive the optimal error estimates of the IFE solution in the Lp norm. Numerical experiments are given to verify the theorems and indicate that the present two-grid algorithms can greatly improve the computing efficiency. © 2019, Shanghai University and Springer-Verlag GmbH Germany, part of Springer Nature.
语种：
英文
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Macrodeformation twinning in a textured aluminum alloy via dynamic equal channel angular pressing
作者：
Qi, D. K.;Tang, M. X.;Lu, L.* ;Zhao, F.;Wang, L.* ;...
期刊：
Journal of Materials Science ,2019年54(5):4314-4324 ISSN：0022-2461
通讯作者：
Lu, L.;Wang, L.
作者机构：
[Luo, S. N.; Lu, L.; Qi, D. K.] Southwest Jiaotong Univ, Key Lab Adv Technol Mat, Minist Educ, Chengdu 610031, Sichuan, Peoples R China.;[Luo, S. N.; Zhao, F.; Tang, M. X.; Lu, L.; Qi, D. K.] Peac Inst Multiscale Sci, Chengdu 610031, Sichuan, Peoples R China.;[Wang, L.] Hunan Agr Univ, Coll Sci, Changsha 410128, Hunan, Peoples R China.
通讯机构：
[Lu, L.] S;[Lu, L.] P;[Wang, L.] H;Southwest Jiaotong Univ, Key Lab Adv Technol Mat, Minist Educ, Chengdu 610031, Sichuan, Peoples R China.;Peac Inst Multiscale Sci, Chengdu 610031, Sichuan, Peoples R China.
关键词：
Equal Channel Angular Pressing;Deformation Twins;Stacking Fault Energies (SFE);Electron Back-scattered Diffraction (EBSD);Longer Grain
摘要：
Dynamic equal channel angular pressing experiments are conducted on an aluminum alloy with impact directions (ID) parallel to the rolling direction (RD), transverse direction (TD) and normal direction (ND), referred to as the ID
$$\parallel $$
RD, ID
$$\parallel $$
TD and ID
$$\parallel $$
ND loading, respectively. Anisotropic deformation twinning is observed as a result of texture and grain elongation along RD, and the deformation twins can be activated both at grain boundaries and within grain interiors. Large-sized deformation twins (tens of
$$\mu $$
m long) form in the ID
$$\parallel $$
RD sample, while few twins are observed in the ID
$$\parallel $$
TD and ID
$$\parallel $$
ND samples during rapid severe plastic deformation. Molecular dynamics simulations are conducted to explain the effects of crystallographic orientations and grain geometry on deformation twinning. The resolved shear stress analysis shows that deformation twinning is easier to occur when the impact direction is along [001] and [110] than [111], and a larger grain dimension along the impact direction leads to a bigger twin size.
语种：
英文
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Variations of Cadmium Accumulation and Translocation in Different Pakchoi Cultivars and Screening for Cd-Pollution-Safe Cultivars Using Cluster Analysis
作者：
Liu, Biqiong;Wu, Fangfang;Dai, Xiongze;Liu, Feng* ;Mi, Baobin*
期刊：
POLISH JOURNAL OF ENVIRONMENTAL STUDIES ,2019年28(4):2215-2221 ISSN：1230-1485
通讯作者：
Liu, Feng;Mi, Baobin
作者机构：
[Liu, Biqiong] Hunan Agr Univ, Coll Biosci & Biotechnol, Changsha, Hunan, Peoples R China.;[Wu, Fangfang] Hunan Agr Univ, Coll Sci, Changsha, Hunan, Peoples R China.;[Dai, Xiongze; Mi, Baobin; Liu, Feng] Hunan Acad Agr Sci, Res Inst Vegetables, Changsha, Hunan, Peoples R China.;[Dai, Xiongze; Mi, Baobin; Liu, Feng] Hunan Acad Agr Sci, Changsha, Hunan, Peoples R China.
通讯机构：
[Liu, F; Mi, BB] H;Hunan Acad Agr Sci, Res Inst Vegetables, Changsha, Hunan, Peoples R China.;Hunan Acad Agr Sci, Changsha, Hunan, Peoples R China.
关键词：
cadmium;pollution-safe cultivar;pakchoi;cluster analysis
摘要：
Screening and breeding of pollution-safe cultivars (PSCs) has become one of the most direct and cost-effective methods for reducing the health risks of heavy metal-contaminated soil. In this paper we identified and screened out cadmium (Cd)-pollution-safe pakchoi cultivars from 30 pakchoi genetype materials through preliminary screening experiments and re-screening experiments in field conditions. We found that in preliminary screening experiments, the Cd uptake displayed significant variability among the 30 selected pakchoi cultivaters grown in soil with a Cd concentration of 0.51 mg/kg. 11 out of the 30 pakchoi cultivars belonged to the low-Cd accumulated cluster classified by cluster analysis, which had the potential to be Cd-PSCs. The re-screening experiments under different Cd levels of contaminated soils in combination with the studies of the enrichment factors (EFs) and translocation factors (TFs) further confirmed the consistency and genotypic stability of the low-Cd accumulating traits of the potential Cd-PSCs. This study proves the feasibility of applying cluster analysis in the process of identifying PSCs. © 2019, HARD Publishing Company. All rights reserved.
语种：
英文
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师生角色互换在材料化学专业课堂教学中的探索
作者：
周智;钟圆;周南;李辉勇
期刊：
化工时刊 ,2019年33(04):56-59 ISSN：1002-154X
作者机构：
湖南农业大学理学院,湖南长沙,410128;[钟圆; 周南; 周智; 李辉勇] 湖南农业大学
关键词：
材料化学;师生角色互换;教学改革
摘要：
针对当代大学生课堂学习中存在的学习兴趣和积极性不高等问题,在材料化学专业课堂教学中引入了师生角色互换的教学模式.在师生角色互换的教学试点,通过建立学习小组,分工合作,教学软件多样化,展示方式多元化,学生教学以及建立演讲竞争机制,学生、老师对教学的点评以及老师对于知识点的补充等环节,营造了融洽的课堂学习氛圉,增强了师生间的互动交流,提高了学生对于课堂学习的兴趣和积极性.
语种：
中文
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浅谈有机化学教学如何培养实用型人才
作者：
张凤;屠小菊
期刊：
化工时刊 ,2019年33(03):51-52 ISSN：1002-154X
作者机构：
湖南农业大学理学院,湖南长沙,410128;湖南农业大学东方科技学院,湖南长沙,410128;[张凤] 湖南农业大学;[屠小菊] 湖南农业大学东方科技学院
关键词：
有机化学教学;创新能力;实用型人才
摘要：
高素质的,具有创新意识的实用型人才培养是21世纪素质教育的重要目标。且培养实用型的人才,是每个高等学校最为重要的任务。在化学教育中培养出实用型人才,并使素质教育更为有力的实施与深入成为一项研究重点。本文分析了目前我校有机化学教学的不足,结合笔者的教学经验,提出了一些教学想法和建议,以达到培养学生综合素质的目的。
语种：
中文
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Transition-metal-free selective pyrimidines and pyridines formation from aromatic ketones, aldehydes and ammonium salts
作者：
Chen, Jinjin;Meng, Huanxin;Zhang, Feng* ;Xiao, Fuhong;Deng, Guo-Jun*
期刊：
Green Chemistry ,2019年21(19):5201-5206 ISSN：1463-9262
通讯作者：
Zhang, Feng;Deng, Guo-Jun
作者机构：
[Zhang, Feng; Deng, GJ; Meng, Huanxin; Chen, Jinjin; Deng, Guo-Jun; Xiao, Fuhong] Xiangtan Univ, Key Lab Green Organ Synth & Applicat Hunan Prov, Key Lab Environmentally Friendly Chem & Applicat, Minist Educ,Coll Chem, Xiangtan 411105, Peoples R China.;[Zhang, Feng] Hunan Agr Univ, Coll Sci, Changsha 410128, Hunan, Peoples R China.
通讯机构：
[Zhang, F; Deng, GJ] X;[Zhang, Feng] H;Xiangtan Univ, Key Lab Green Organ Synth & Applicat Hunan Prov, Key Lab Environmentally Friendly Chem & Applicat, Minist Educ,Coll Chem, Xiangtan 411105, Peoples R China.;Hunan Agr Univ, Coll Sci, Changsha 410128, Hunan, Peoples R China.
摘要：
An efficient synthesis of pyrimidines and pyridines has been developed from readily available aromatic ketones, aldehydes and ammonium salts under transition-metal-free conditions. In this strategy, ammonium salts were used as nitrogen sources and only water was generated as a nontoxic byproduct. A catalytic amount of NaIO4 played an important role in the selectivity control, whereas substituted pyridines were dominantly formed in its absence. © 2019 The Royal Society of Chemistry.
语种：
英文
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Improving the electrochemical properties of SiO@C anode for high-energy lithium ion battery by adding graphite through fluidization thermal chemical vapor deposition method
作者：
Xia, Mao;Li, Yiran;Zhou, Zhi;Wu, Yufan;Zhou, Nan;...
期刊：
Ceramics International ,2019年45(2):1950-1959 ISSN：0272-8842
通讯作者：
Zhang, Hongbo;Xiong, Xiang
作者机构：
[Xia, Mao; Xiong, Xiang; Zhang, Hongbo] Cent S Univ, State Key Lab Powder Met, Changsha 410083, Hunan, Peoples R China.;[Wu, Yufan; Zhou, Zhi; Zhou, Nan; Li, Yiran] Hunan Agr Univ, Coll Sci, Hunan Prov Engn Technol Res Ctr Opt Agr, 1 Nongda Rd, Changsha 410128, Hunan, Peoples R China.
通讯机构：
[Zhang, HB; Xiong, X] C;Cent S Univ, State Key Lab Powder Met, Changsha 410083, Hunan, Peoples R China.
关键词：
Fluidization thermal chemical vapor deposition;Lithium ion batteries;Silicon monoxide;SiO/[email protected]
摘要：
A series SiO/[email protected] (SGC) composites electrode are successfully prepared by a fluidization thermal chemical vapor deposition (FTCVD) route in a kilogram-scale fluidized bed CVD equipment. This strategy can avoid the effect of particle agglomeration on carbon coating during heating reaction. The phase composition, element distribution, particle appearance and electrochemical properties of the as-obtained SGC composite is investigated in detail. The charge specific capacity of SGC-37 is close to 799.1 mAh g−1 after 100 cycles at 200 mA g−1. The SGC-37 shows a high capacity retention of 93.7% after 100 cycles, which much higher than that of SiO, [email protected], SGC-73 and SGC-55 (the retention rates are 26.3%, 56.8%, 75.5% and 89.6%, respectively). The reason is mainly because improve Li ion diffusion coefficient, shorten transfer pathway of Li ion and ease to the volume change of SiO due to surface carbon coating and graphite addition. The FTCVD methods is not only an efficient method to prepared SGC anode, but also is may easy to apply to surface carbon coating of another particle material. © 2018 Elsevier Ltd and Techna Group S.r.l.
语种：
英文
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Improving the electrochemical properties of a SiO@C/graphite composite anode for high-energy lithium-ion batteries by adding lithium fluoride
作者：
Xia, Mao;Li, Yi-ran;Wu, Yu-fan;Zhang, Hong-bo;Yang, Jian-kui;...
期刊：
Applied Surface Science ,2019年480:410-418 ISSN：0169-4332
通讯作者：
Xiong, Xiang;Zhou, Zhi
作者机构：
[Xia, Mao; Xiong, Xiang; Zhang, Hong-bo] Cent S Univ, State Key Lab Powder Met, Changsha 410083, Hunan, Peoples R China.;[Li, Yi-ran; Yang, Jian-kui; Wu, Yu-fan; Zhou, Nan; Zhou, Zhi] Hunan Agr Univ, Coll Sci, Hunan Prov Engn Technol Res Ctr Opt Agr, 1 Nongda Rd, Changsha 410128, Hunan, Peoples R China.
通讯机构：
[Xiong, Xiang] C;[Zhou, Zhi] H;Cent S Univ, State Key Lab Powder Met, Changsha 410083, Hunan, Peoples R China.;Hunan Agr Univ, Coll Sci, Hunan Prov Engn Technol Res Ctr Opt Agr, 1 Nongda Rd, Changsha 410128, Hunan, Peoples R China.
关键词：
Chemical vapor deposition;Lithium fluoride modification;Lithium-ion batteries;Solid electrolyte interphase film;[email protected]/graphite
摘要：
Silicon monoxide has attracted wide interest as a negative material for lithium-ion batteries because of its high theoretical capacity. Moreover, in this paper, lithium fluoride serves as an additive, which can improve the initial coulombic efficiency of silicon monoxide-based electrodes. This work develops a simple two-step method to prepare a lithium fluoride-modified [email protected]/graphite composite as an anode for lithium-ion batteries. First, [email protected] is prepared via a chemical vapor deposition method; then, [email protected]/graphite-LiF is obtained by mixing [email protected], graphite and LiF in a stirrer. The phase composition, particle appearance and electrochemical properties of the [email protected]/graphite-LiF composites are characterized via X-ray diffraction, scanning electron microscopy, electrochemical impedance spectroscopy, cyclic voltammetry and galvanostatic charge and discharge analyses. The [email protected]/graphite-7.5% LiF composite shows a high capacity retention rate of over 91% after 100 cycles. The capacity of [email protected]/graphite-LiF is close to 200 mAh g −1 at 3.2 A g −1 , which is much higher than that of [email protected]/graphite (only 21 mAh g −1 ). This result is mainly because Li ion transport is improved during the lithiation/delithiation process and stabilizes the solid electrolyte interface layer due to lithium fluoride addition. The encouraging results suggest that adding lithium fluoride to SiO-based materials is an effective strategy to improve the electrochemical properties and can be applied to high-energy storage systems. © 2019 Elsevier B.V.
语种：
英文
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A three-component approach to isoxazolines and isoxazoles under metal-free conditions
作者：
Wang, Dahan;Zhang, Feng;Xiao, Fuhong* ;Deng, Guo-Jun*
期刊：
Organic & Biomolecular Chemistry ,2019年17(41):9163-9168 ISSN：1477-0520
通讯作者：
Xiao, Fuhong;Deng, Guo-Jun
作者机构：
[Wang, Dahan; Xiao, Fuhong; Deng, GJ; Deng, Guo-Jun] Xiangtan Univ, Coll Chem, Key Lab Environm Friendly Chem & Applicat, Minist Educ,Key Lab Green Organ Synth & Applicat, Xiangtan 411105, Peoples R China.;[Zhang, Feng] Hunan Agr Univ, Coll Sci, Changsha 410128, Hunan, Peoples R China.
通讯机构：
[Xiao, FH; Deng, GJ] X;Xiangtan Univ, Coll Chem, Key Lab Environm Friendly Chem & Applicat, Minist Educ,Key Lab Green Organ Synth & Applicat, Xiangtan 411105, Peoples R China.
摘要：
A 1,3-dipolar cycloaddition of 2-methylquinoline, tert-butyl nitrite (TBN) and alkynes or alkenes for the synthesis of biheteroaryls containing both isoxazoline/isoxazole and quinoline motifs has been developed. In this protocol, TBN serves as a convenient N-O source to convert 2-methylquinoline into intermediate nitrile oxides in situ.
语种：
英文
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Revealing the Reaction Mechanism of Sodium Selenide Confined within a Single-Walled Carbon Nanotube: Implications for Na-Se Batteries
作者：
Wang, Liang;Zhang, Xingming;Deng, Lei;Tang, Jianfeng;Deng, Huiqiu* ;...
期刊：
ACS Applied Materials & Interfaces ,2019年11(5):4995-5002 ISSN：1944-8244
通讯作者：
Deng, Huiqiu;Hu, Wangyu;Liu, Zhixiao
作者机构：
[Deng, Lei; Tang, Jianfeng; Wang, Liang; Zhang, Xingming] Hunan Agr Univ, Coll Sci, Changsha 410128, Hunan, Peoples R China.;[Deng, Huiqiu] Hunan Univ, Sch Phys & Elect, Changsha 410082, Hunan, Peoples R China.;[Hu, Wangyu; Liu, Zhixiao] Hunan Univ, Coll Mat Sci & Engn, Changsha 410082, Hunan, Peoples R China.
通讯机构：
[Deng, Huiqiu; Hu, WY; Liu, ZX] H;Hunan Univ, Sch Phys & Elect, Changsha 410082, Hunan, Peoples R China.;Hunan Univ, Coll Mat Sci & Engn, Changsha 410082, Hunan, Peoples R China.
关键词：
Na-Se battery;ab initio molecular dynamics;conductivity;density functional theory computation;nanoconfinement;polaron;reaction mechanism
摘要：
The sodium-selenium (Na-Se) battery is a competitive candidate as the practical next-generation energy storage device. A Na 16 Se 8 cluster confined within a (10, 10) single-walled carbon nanotube is constructed to reveal the nanoconfinement effect on the reaction mechanism of the Na-Se battery cathode. It is found that the nanoconfinement can enhance the electronic conductivity of Na x≥12 Se 8 nanostructures because itinerant electrons appear under this condition. During desodiation, polyselenide chains grow longer and the intermediate products become insulators for transferring electrons. However, hole polarons have the potential to act as charge carriers in Na x≤10 Se 8 nanostructures. The open-circuit voltage profile is plotted, and the voltage window is 1.67 ≤ U ≤ 1 V. After the first charge cycle, the cathode cannot discharge to Na 16 Se 8 , but the reversible specific capacity can still arrive at 302 mA h/g of the cathode composite. © 2019 American Chemical Society.
语种：
英文
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初中生自主管理策略研究
作者：
武小亭;方成智;武芳芳
期刊：
科教导刊 ,2019年(28):179-180 ISSN：1674-6813
作者机构：
湖南农业大学教育学院 湖南·长沙 410128;湖南农业大学理学院 湖南·长沙 410128;[武芳芳; 方成智; 武小亭] 湖南农业大学
关键词：
初中;自主管理;现状;策略
摘要：
随着新课程改革的推进及以人为本理念的深入发展,传统的班主任为主的管理方式已不能适应新时期学生发展的需要,以学生为主体的教育管理方法成为了目前众多教育家研究的内容。班级管理作为学校工作的基础、教育教学活动开展的保证已成为了学校高层领导与班主任班级管理的新趋势和重要研究课题。本文从学生自主管理的意义出发,分析当下初中班级管理现状,提出了初中学生自主管理的策略。
语种：
中文
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A novel near-infrared fluorescent probe with a "donor--acceptor" type structure and its application in the selective detection of cysteine in living cells
作者：
Hong, Haojia;Shi, Lei* ;Huang, Junzhe;Peng, Chang* ;Yang, Sheng;...
期刊：
NEW JOURNAL OF CHEMISTRY ,2019年43(1):72-76 ISSN：1144-0546
通讯作者：
Shi, Lei;Gong, Shengzhao;Peng, Chang
作者机构：
[Gong, Shengzhao; Hong, Haojia; Shi, Lei; Huang, Junzhe] Guangdong Ind Polytech, Sch Chem Engn & Technol, Guangzhou 510300, Guangdong, Peoples R China.;[Peng, Chang] Hunan Agr Univ, Coll Sci, Changsha 411105, Hunan, Peoples R China.;[Yang, Sheng] Changsha Univ Sci & Technol, Sch Chem & Biol Engn, Hunan Prov Key Lab Mat Protect Elect Power & Tran, Changsha 410114, Hunan, Peoples R China.;[Shao, Guang] Sun Yat Sen Univ, Sch Chem, Guangzhou 510275, Guangdong, Peoples R China.
通讯机构：
[Shi, L; Gong, SZ] G;[Peng, Chang] H;Guangdong Ind Polytech, Sch Chem Engn & Technol, Guangzhou 510300, Guangdong, Peoples R China.;Hunan Agr Univ, Coll Sci, Changsha 411105, Hunan, Peoples R China.
摘要：
The development of imaging-suitable fluorescent probes based on fluorogen scaffolds with near-infrared emission is crucial for monitoring cysteine (Cys) in biological systems. Herein, we synthesized a novel NIR dye based on a donor--acceptor structure which exhibits good Stokes shifts, satisfactory quantum yields, long wavelength excitation and excellent photostability, and a Cys-responsive NIR probe was constructed by decoration with methacrylate. The designed probe possesses great sensitivity and selectivity for detection of Cys. Moreover, it has been successfully applied in detecting Cys in living cells, indicating its great potential value for biological applications.
语种：
英文
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一步电沉积制备多孔石墨烯/金纳米复合材料修饰电极测定芦丁
作者：
李文彬;刘晓颖
期刊：
云南化工 ,2019年46(7):74-75 ISSN：1004-275X
作者机构：
湖南农业大学理学院,湖南 长沙,410000;[刘晓颖; 李文彬] 湖南农业大学
关键词：
多孔石墨烯;纳米金;电化学检测;芦丁
摘要：
在玻碳电极(GCE)上覆盖一层多孔石墨烯/金纳米复合材料,制备了一种简单、 低成本、高灵敏度的电化学传感器应用于芦丁的测定.考察了沉积圈数、 缓冲液pH值对芦丁反应的影响.采用差分脉冲伏安法在优化条件下,芦丁浓度在1nmol/L～1μmol/L和1μmol/L～10μmol/L范围内与其氧化峰电流呈良好的线性关系,最低检出限为0.35nmol/L.
语种：
中文
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A novel MnO 2 /MXene composite prepared by electrostatic self-assembly and its use as an electrode for enhanced supercapacitive performance
作者：
Chen, Shu;Xiang, Yuanfang;Xu, Weijian* ;Peng, Chang*
期刊：
无机化学前沿 ,2019年6(1):199-208 ISSN：2052-1553
通讯作者：
Xu, Weijian;Peng, Chang
作者机构：
[Xu, WJ; Peng, C; Xu, Weijian; Peng, Chang; Chen, Shu; Xiang, Yuanfang] Hunan Univ, Coll Chem & Chem Engn, Changsha 410082, Hunan, Peoples R China.;[Peng, Chang] Hunan Agr Univ, Coll Sci, Changsha 410128, Hunan, Peoples R China.
通讯机构：
[Xu, WJ; Peng, C; Peng, Chang] H;Hunan Univ, Coll Chem & Chem Engn, Changsha 410082, Hunan, Peoples R China.;Hunan Agr Univ, Coll Sci, Changsha 410128, Hunan, Peoples R China.
摘要：
MXene is a new 2D transition metal carbide possessing metallic conductivity and hydrophilic surfaces. It has drawn widespread attention as a potential material for electrode use. However, the applications of MXene are limited by its property of low electrical capacity. In this paper, a novel MnO 2 /MXene composite is prepared by electrostatic self-assembly. Firstly, delaminated MnO 2 nanosheets are obtained through the intercalation delamination of multilayered H-MnO 2 in a cationic Gemini surfactant (Gem) solution, leading to a positively charged surface. Then, the positive MnO 2 nanosheets are assembled on negative MXene nanosheets through electrostatic self-assembly to form a MnO 2 /MXene composite. The characterization results show that the MnO 2 nanosheets are intimately assembled on the MXene nanosheets. As an electrode material, the MnO 2 /MXene composite displays a specific capacitance of 340 F g -1 at 1 A g -1 , which is three times the performance of an MXene electrode. In addition, the MnO 2 /MXene electrode shows a high retention rate (90.3% retention at 10 A g -1 ) and good cycling life (87.6% of the initial specific capacitance is retained after 2000 cycles at 4 A g -1 ). The properties of the proposed composite are attributed to the excellent conductivity of MXene and the high specific capacitance of MnO 2 . © 2019 the Partner Organisations.
语种：
英文
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Identifying the origin and contribution of pseudocapacitive sodium ion storage in tungsten disulphide nanosheets for application in sodium-ion capacitors
作者：
Ding, Chunxia* ;Huang, Ting;Tao, Yaping;Tan, Deming;Zhang, Yin;...
期刊：
Journal of Materials Chemistry A ,2018年6(42):21010-21017 ISSN：2050-7488
通讯作者：
Ding, Chunxia;Xie, Qingji
作者机构：
[Ding, Chunxia] Hunan Agr Univ, Coll Sci, Changsha 410128, Hunan, Peoples R China.;[Tao, Yaping] Luoyang Normal Univ, Coll Phys & Elect Informat, Luoyang 471022, Peoples R China.;[Xie, Qingji; Huang, Ting] Hunan Normal Univ, Coll Chem & Chem Engn, Minist Educ China, Key Lab Chem Biol & Tradit Chinese Med Res, Changsha 410081, Hunan, Peoples R China.;[Zhang, Yin; Yu, Feng] Queensland Univ Technol, Fac Sci & Engn, Sch Chem Phys & Mech Engn, Brisbane, Qld, Australia.;[Tan, Deming; Wang, Faxing] Tech Univ Dresden, Dept Chem & Food Chem, D-01062 Dresden, Germany.
通讯机构：
[Ding, Chunxia; Xie, Qingji] H;Hunan Agr Univ, Coll Sci, Changsha 410128, Hunan, Peoples R China.;Hunan Normal Univ, Coll Chem & Chem Engn, Minist Educ China, Key Lab Chem Biol & Tradit Chinese Med Res, Changsha 410081, Hunan, Peoples R China.
摘要：
Sodium (Na)-ion capacitors are emerging as one of the most promising hybrid devices for next generation electrochemical energy storage systems because of their abundant resources, and environmentally friendly nature as well as the potential integration of Na-ion batteries with high energy density and electrochemical capacitors with high power density. However, the practical application of Na-ion capacitors is severely hampered by the sluggish redox kinetics in anodes. To overcome this obstacle, the most effective approach is to develop a pseudocapacitive anode material for Na ion storage. Here, we demonstrate a predominant pseudocapacitive contribution for Na ion storage in tungsten disulphide (WS 2 ) nanosheets within the potential window of 1-3 V vs. Na/Na + . Particularly, the root cause of pseudocapacitive Na ion storage in WS 2 nanosheets was systematically investigated by operando X-ray diffraction (XRD), ex situ synchronous radiation tests and density functional theory (DFT) simulations. This work may provide a fundamental insight into the development of pseudocapacitive materials for electrochemical energy storage systems. © The Royal Society of Chemistry.
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英文
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Hierarchical Carbon Micro/Nanonetwork with Superior Electrocatalysis for High-Rate and Endurable Vanadium Redox Flow Batteries
作者：
Ling, Wei;Deng, Qi;Ma, Qiang;Wang, Hong-Rui;Zhou, Chun-Jiao;...
期刊：
Advanced Science ,2018年5(12):1801281- ISSN：2198-3844
通讯作者：
Wu, Xiong-Wei;Zeng, Xian-Xiang;Guo, Yu-Guo
作者机构：
[Ma, Qiang; Xu, Jian-Kai; Wu, Xiong-Wei; Wu, XW; Zeng, Xian-Xiang; Ling, Wei; Wang, Hong-Rui; Deng, Qi; Zhou, Chun-Jiao] Hunan Agr Univ, Coll Sci, Changsha 410128, Hunan, Peoples R China.;[Ma, Qiang; Ling, Wei; Yin, Ya-Xia; Guo, Yu-Guo] Chinese Acad Sci, Inst Chem, CAS Res Educ Ctr Excellence Mol Sci, CAS Key Lab Mol Nanostruct & Nanotechnol, Beijing 100190, Peoples R China.;[Wu, Xiong-Wei; Deng, Qi] Hunan Prov Yin Feng New Energy Co Ltd, Changsha 410000, Hunan, Peoples R China.
通讯机构：
[Wu, XW; Zeng, XX; Wu, Xiong-Wei] H;[Guo, Yu-Guo] C;Hunan Agr Univ, Coll Sci, Changsha 410128, Hunan, Peoples R China.;Chinese Acad Sci, Inst Chem, CAS Res Educ Ctr Excellence Mol Sci, CAS Key Lab Mol Nanostruct & Nanotechnol, Beijing 100190, Peoples R China.;Hunan Prov Yin Feng New Energy Co Ltd, Changsha 410000, Hunan, Peoples R China.
关键词：
carbon electrodes;durable cycle life;hierarchical carbon micro/nanonetworks;high-rate performance;vanadium redox flow batteries
摘要：
Vanadium redox flow batteries (VRFBs) are receiving increasing interest in energy storage fields because of their safety and versatility. However, the electrocatalytic activity of the electrode is a pivotal factor that still restricts the power and cycling capabilities of VRFBs. Here, a hierarchical carbon micro/nanonetwork (HCN) electrode codoped with nitrogen and phosphorus is prepared for application in VRFBs by cross-linking polymerization of aniline and physic acid, and subsequent pyrolysis on graphite felt. Due to the hierarchical electron pathways and abundant heteroatom active sites, the HCN exhibits superior electrocatalysis toward the vanadium redox couples and imparts the VRFBs with an outstanding energy efficiency and extraordinary stability after 2000 cycles at 250 mA cm−2 and a discharge capacity of 10.5 mA h mL−1 at an extra-large current density of 400 mA cm−2. Such a micro/nanostructure design will force the advancement of durable and high-power VRFBs and other electrochemical energy storage devices. © 2018 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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英文
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Cu-MOF-Derived Cu/Cu2O Nanoparticles and CuNxCy Species to Boost Oxygen Reduction Activity of Ketjenblack Carbon in Al-Air Battery
作者：
Li, Jingsha;Zhou, Nan;Song, Jingya;Fu, Liang;Yan, Jun;...
期刊：
ACS SUSTAINABLE CHEMISTRY & ENGINEERING ,2018年6(1):413-421 ISSN：2168-0485
通讯作者：
Tang, Yougen;Wang, Haiyan
作者机构：
[Wang, Haiyan; Li, Jingsha; Tang, Yougen; Wang, HY; Yan, Jun; Song, Jingya] Cent S Univ, Coll Chem & Chem Engn, Hunan Prov Key Lab Efficient & Clean Utilizat Man, Lushan South Rd, Changsha 410083, Hunan, Peoples R China.;[Zhou, Nan] Hunan Agr Univ, Coll Sci, Nongda Rd, Changsha 410128, Hunan, Peoples R China.;[Fu, Liang] Yangtze Normal Univ, Coll Chem & Chem Engn, Ju Xian Rd, Fuling 408100, Peoples R China.;[Wang, Haiyan; Tang, Yougen; Wang, HY] Nankai Univ, Minist Educ, Key Lab Adv Energy Mat Chem, Weijin Rd, Tianjin 300071, Peoples R China.
通讯机构：
[Tang, YG; Wang, HY] C;[Tang, YG; Wang, HY] N;Cent S Univ, Coll Chem & Chem Engn, Hunan Prov Key Lab Efficient & Clean Utilizat Man, Lushan South Rd, Changsha 410083, Hunan, Peoples R China.;Nankai Univ, Minist Educ, Key Lab Adv Energy Mat Chem, Weijin Rd, Tianjin 300071, Peoples R China.
关键词：
Al-air batteries;Cu 2 O;Metallic Cu nanoparticles;Noncrystalline CuN x C y species;Oxygen reduction reaction
摘要：
Developing a highly efficient and low-cost catalyst on a large scale is still a big challenge for fuel cells and metal-air batteries. Decorating carbon supports with some active sites (e.g., nitrogen doping, metal-nitrogen doping) seems to be a promising strategy. In this work, we first reported a Cu-centered metal organic framework (Cu-MOF) as a self-sacrificing precursor to modify the Ketjenblack (KB) carbon, where crystalline Cu/Cu<inf>2</inf>O nanoparticles and noncrystalline CuN<inf>x</inf>C<inf>y</inf>species were derived after calcination. The catalytic activity toward the oxygen reduction reaction (ORR) of this modified KB carbon was significantly boosted probably because of the synergistic effect between crystalline Cu/Cu<inf>2</inf>O nanoparticles and noncrystalline CuN<inf>x</inf>C<inf>y</inf>species. This hybrid catalyst exhibited a comparable half-wave potential (0.82 V versus reversible hydrogen electrode, RHE) and superior limiting-current density and durability to the commercial 20 wt % Pt/C. The excellent activity was also further confirmed by the application in home-made Al-air batteries, yielding a highly stable voltage of 1.53 V at a current density of 40 mA cm<sup>-2</sup>.<br/> ©2017 American Chemical Society.
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英文
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Generation of sulfonated 1-isoindolinones through a multicomponent reaction with the insertion of sulfur dioxide
作者：
Zhang, Jun;Zhang, Feng;Lai, Lifang;Cheng, Jiang;Sun, Jiangtao;...
期刊：
Chemical Communications ,2018年54(31):3891-3894 ISSN：1359-7345
通讯作者：
Wu, Jie
作者机构：
[Wu, Jie; Zhang, Jun] Fudan Univ, Dept Chem, Jiangwan Campus,2005 Songhu Rd, Shanghai 200438, Peoples R China.;[Zhang, Feng] Hunan Agr Univ, Coll Sci, Changsha 410128, Hunan, Peoples R China.;[Sun, Jiangtao; Lai, Lifang; Cheng, Jiang] Changzhou Univ, Jiangsu Key Lab Adv Catalyt Mat & Technol, Sch Petrochem Engn, Changzhou 213164, Peoples R China.
通讯机构：
[Wu, Jie] F;Fudan Univ, Dept Chem, Jiangwan Campus,2005 Songhu Rd, Shanghai 200438, Peoples R China.
摘要：
A four-component reaction of 2-vinylbenzoic acids, aryldiazonium tetrafluoroborates, the sulfur dioxide surrogate DABCO·(SO 2 ) 2 , and nitriles under photocatalysis in the presence of visible light is developed. This multicomponent reaction works efficiently, promoted by BF 3 ·OEt 2 with the insertion of sulfur dioxide under mild conditions, leading to sulfonated 1-isoindolinones in moderate to good yields. This route is highly selective, and several competitive pathways are not observed under these conditions. A possible mechanism involving photocatalysis and a Lewis acid is proposed. © 2018 The Royal Society of Chemistry.
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英文
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多元线性回归在MATLAB中的实现
作者：
李立欣;许健开
期刊：
内蒙古科技与经济 ,2018年(13):36-37 ISSN：1007-6921
作者机构：
湖南农业大学理学院
关键词：
多元线性回归;MATLAB软件;应用
摘要：
针对研究中经常用到的多元线性回归方法,简单介绍了多元线性回归的基本原理,结合1989年~2003年全国的财政收入的统计数据,详细介绍了运用MATLAB软件编写回归算法,建立回归模型,并对模型进行拟合优度判定、检验和检验,结果表明：模型的拟合程度和显著性效果较好,算法简单实用,求解过程方便,能广泛用于多元线性回归问题的求解。
语种：
中文
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Balancing strength, hardness and ductility of Cu64Zr36 nanoglasses via embedded nanocrystals
作者：
Jian, W. R.* ;Wang, L.;Yao, X. H.;Luo, S. N.
期刊：
Nanotechnology ,2018年29(2):025701- ISSN：0957-4484
通讯作者：
Jian, W. R.
作者机构：
[Jian, W. R.; Yao, X. H.] South China Univ Technol, Dept Engn Mech, Guangzhou 510640, Guangdong, Peoples R China.;[Luo, S. N.; Jian, W. R.] Southwest Jiaotong Univ, Key Lab Adv Technol Mat, Minist Educ, Chengdu 610031, Sichuan, Peoples R China.;[Luo, S. N.; Jian, W. R.] Peac Inst Multiscale Sci, Chengdu 610031, Sichuan, Peoples R China.;[Wang, L.] Hunan Agr Univ, Coll Sci, Changsha 410028, Hunan, Peoples R China.
通讯机构：
[Jian, W. R.] S;[Jian, W. R.] P;South China Univ Technol, Dept Engn Mech, Guangzhou 510640, Guangdong, Peoples R China.;Southwest Jiaotong Univ, Key Lab Adv Technol Mat, Minist Educ, Chengdu 610031, Sichuan, Peoples R China.;Peac Inst Multiscale Sci, Chengdu 610031, Sichuan, Peoples R China.
关键词：
metallic glass;nanocomposite;interfaces;high strength;high hardness;superior ductility
摘要：
Superplasticity can be achieved in nanoglasses but at the expense of strength, and such a loss can be mitigated via embedding stronger nanocrystals, i.e., forming nanoglass/nanocrystal composites. As an illustrative case, we investigate plastic deformation of Cu<inf>64</inf>Zr<inf>36</inf>nanoglass/nanocrystalline Cu composites during uniaxial tension and nanoindentation tests with molecular dynamics simulations. With an increasing fraction of nanocrystalline grains, the tensile strength of the composite is enhanced, while its ductility decreases. The dominant interface type changes from a glass-glass interface to glass-crystal interface to grain boundary, corresponding to a failure mode transition from superplastic flow to shear banding to brittle intercrystal fracture, respectively. Accordingly, the indentation hardness increases continuously and strain localization beneath the indenter is more and more severe. For an appropriate fraction of nanocrystalline grains, a good balance among strength, hardness and ductility can be realized, which is useful for the synthesis of novel nanograined glass/crystalline composites with high strength, high hardness and superior ductility.<br/> ©2017 IOP Publishing Ltd.
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