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Gigahertz Dielectric Polarization of Substitutional Single Niobium Atoms in Defective Graphitic Layers

Physical Review Letters 2015年第14期115卷 147601-147601页

作者： Xuefeng Zhang Junjie Guo Pengfei Guan Gaowu Qin Stephen J. Pennycook Key Laboratory for Anisotropy and Texture of Materials (MOE) School of Materials Science and Engineering Northeastern University Shenyang 110819 P. R. China National Research Council Canada 75 de Mortagne Boucherville Québec J4B 6Y4 Canada Materials Science and Technology Division Oak Ridge National Laboratory Oak Ridge Tennessee 37831 USA Key Laboratory of Interface Science and Engineering in Advanced Materials of Ministry of Education Taiyuan University of Technology Taiyuan 030024 P. R. China Beijing Computational Science Research Center Beijing 100084 China Department of Materials Science and Engineering National University of Singapore Singapore 117576 Singapore

We synthesize two Nb/C composites with an order of magnitude difference in the density of single niobium atoms substituted into defective graphitic layers. The concentration and sites of single Nb atoms are identified using aberration-corrected scanning transmission electron microscopy and density functional theory. Comparing the experimental complex permittivity spectra reveals that a representative dielectric resonance at ∼16 GHz originates from the intrinsic polarization of single Nb atom sites, which is confirmed by theoretical simulations. The single-atom dielectric resonance represents the physical limit of the electromagnetic response of condensed matter, and thus might open up a new avenue for designing electromagnetic wave absorption materials. Single-atom resonance also has important implications in understanding the correlation between the macroscopic dielectric behaviors and the atomic-scale structural origin.

关键词： Resonance

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Cation Intercalation in Manganese Oxide Nanosheets: Effects on Lithium and Sodium Storage

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Angewandte Chemie 2016年第35期128卷

作者： Ke Lu Ziyu Hu Zhonghua Xiang Jizhen Ma Bin Song Jintao Zhang Houyi Ma Key Laboratory for Colloid and Interface Chemistry of State Education Ministry School of Chemistry and Chemical Engineering Shandong University Jinan 250100 China Beijing Computational Science Research Center No.10 East Xibeiwang Road Haidian District Beijing 100193 China State Key Laboratory of Organic-Inorganic Composites Beijing University of Chemical Technology Beijing 100029 China Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices Institute of Functional Nano and Soft Materials (FUNSOM) Soochow University Suzhou 215123 China

The rapid development of advanced energy‐storage devices requires significant improvements of the electrode performance and a detailed understanding of the fundamental energy‐storage processes. In this work, the self‐assembly of two‐dimensional manganese oxide nanosheets with various metal cations is introduced as a general and effective method for the incorporation of different guest cations and the formation of sandwich structures with tunable interlayer distances, leading to the formation of 3D M x MnO 2 (M=Li, Na, K, Co, and Mg) cathodes. For sodium and lithium storage, these electrode materials exhibited different capacities and cycling stabilities. The efficiency of the storage process is influenced not only by the interlayer spacing but also by the interaction between the host cations and shutter ions, confirming the crucial role of the cations. These results provide promising ideas for the rational design of advanced electrodes for Li and Na storage.

关键词： Elektrochemie Manganoxid Nanoschichten Sandwich-Strukturen Selbstorganisation

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Volume calculation of the spur gear billet for cold precision forging with average circle method

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International Journal of Coal science & Technology 2014年第4期1卷 456-462页

作者： Wangjun Cheng Chengzhong Chi Yongzhen Wang Peng Lin Wei Liang Chen Li College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan 030024China Key Laboratory of Interface Science and Engineering in Advanced Materials Ministry of EducationTaiyuan University of TechnologyTaiyuan 030024China

Forging spur gears are widely used in the driving system of mining machinery and equipment due to their higher strength and dimensional *** the purpose of precisely calculating the volume of cylindrical spur gear billet in cold precision forging,a new theoretical method named average circle method was put *** this method,a series of gear billet volumes were *** with the accurate three-dimensional modeling method,the accuracy of average circle method by theoretical calculation was estimated and the maximum relative error of average circle method was less than 1.5%,which was in good agreement with the experimental *** errors of the calculated and the experimental for obtaining the gear billet volumes with reference circle method are larger than those of the average circle *** shows that average circle method possesses a higher calculation accuracy than reference circle method(traditional method),which should be worth popularizing widely in calculation of spur gear billet volume.

关键词： Gear billet volume Three-dimensional modeling Cold precision forging Average circle

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AN INTERESTING SCENARIO IN VIVO PERFORMANCE OF MRI MITOCHONDRIA-TARGETED GD AGENTS

AN INTERESTING SCENARIO IN VIVO PERFORMANCE OF MRI MITOCHOND...

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第十四次中国暨国际生物物理大会（ICBC2015）

作者： Hongyan ZHANG Yanhui ZHANG Binbin LI Bo TAN Hailu ZHANG Zongwu DENG Key Laboratory of Nano-Biological Interface and Division of Nanobionics Suzhou Institute of Nano-tech and Nano-bionics Chinese Academy of Sciences Institute of Environmental and Chemical Engineering Shanghai University College of Sciences Shanghai University Institute of Nanoscience and Nanotechnology University of Science and Technology of China

A simple and straightforward strategy for magnetic resonance imaging(MRI) of stem cell transplants in terms of their viability,migration and homing,response to various endogenous stimuli has been pursued over *** demo... 详细信息

关键词： MRI AN INTERESTING SCENARIO IN VIVO PERFORMANCE OF MRI MITOCHONDRIA-TARGETED GD AGENTS

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Investigation on the constructionconditions of carbon coating of core-shell LiFePO4/C composites via rate-discharge and cyclic performance tests

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Gongneng Cailiao/Journal of Functional Materials 2015年第5期46卷 05142-05146页

作者： Liu, Zhen-Xin Li, Jing-Jing Xing, Yu Xu, Bei Xue, Ying-Ying Wu, De-Peng Fang, Shao-Ming Wang, Li-Zhen Qu, Xiong-Wei School of Materials Science and Engineering Hebei University of Technology Tianjin China Henan Provincial Key Laboratory of Surface and Interface Science School of Materials and Chemical Engineering Zhengzhou University of Light Industry Zhengzhou China

There are many literature about the construction issues of LiFePO4's carbon coating, of which is difficult to figure out the relevant details. However, the rate-discharge and cyclic performances are important for lithium-ion battery materials. Thus we conducted tests on the rate-discharge and cyclic performances to tell the differences between the functions of element-type and compound-type carbon sources and, in the mean time, to study the effects of carbon content as well as carbonization condition. The effects of element-type carbon sources (i. e, graphite nanopowder and acetylene black) and compound-type carbon sources (i. e, hydroxyethyl cellulose, polyethyleneglycol 2000 and glucose) on the electrochemical performance of LiFePO4/C were investigated. The bench research produced following results. The overall performances of glucose and graphite nanopowder are better than other carbon sources. In the case of using a certain carbon source, both carbon content and calcinations temperature have much more significant effects on the materials' high-rate performances than their low-rate performances. In the case of using a certain carbon content and a certain calcinations temperature, the factor of carbon source has effects to some extent on the initial low-rate performances of LiFePO4/C composites, has a little more significant effects on their low-rate cyclic performances, and has very significant effects on their high-rate performances. ©, 2015, Journal of Functional Materials. All right reserved.

关键词： Iron compounds

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Effect of cooling rate on morphology and corrosion resistance of Zn-Al-Mg alloy

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Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment 2015年第4期36卷 49-55页

作者： Ma, Rui-Na Fan, Yong-Zhe Du, An Zhang, Ping-Ping School of Material Science and Engineering Hebei University of Technology Tianjin China Tianjin Key Laboratory of Materials Laminating Fabrication and Interface Control Technology Tianjin China

Microstructure of Zn-6%Al-3%Mg alloy after solidification with different cooling rates was investigated, and its corrosion resistance was analyzed. The results show that microstructure of the alloy at different solidification rates consists of primary crystal Al phase, primary crystal Al phase and Zn phase, Al/MgZn2 binary eutectic and Zn/Al/MgZn2 ternary eutectic structure. Zn/Al/Mg2Zn11 ternary eutectic structure in the alloy by furnace cooling and water cooling is also observed. With the increasing cooling rates, the grains sizes become finer. The corrosion resistance of the alloy by air cooling is better than that of the alloy by water cooling, which is attributed to the different grain sizes and formation of Mg2Zn11 phase. ©, 2015, Editorial Office of Transactions of Materials and Heat Treatment. All right reserved.

关键词： Aluminum alloys

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Effect of trace element La on microstructure and properties of Mg-8Al-4Sr-1Y alloy

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Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment 2015年第3期36卷 125-129页

作者： Fan, Jin-Pin Fang, Lu-Lu Xu, Bing-She College of Materials Science and Engineering Taiyuan University of Technology Taiyuan China Shanxi Research Center of Advanced Materials Science and Technology Taiyuan China Key Laboratory of Interface Science and Engineering in Advanced Materials Ministry of Education Taiyuan China

4 groups of Mg-8Al-4Sr-1Y-xLa (x=0, 0.01%, 0.05%, 0.10%) alloy were prepared by vacuum resistant smelting furnace. The effects of small amounts of rare earth element La on the microstructure and properties of the alloy were studied by OM, SEM, EDS, XRD, WDW-100kN tensile testing machine and RWS50 high temperature creep tester. Results show that the grain of Mg-8Al-4Sr-1Y alloy can be refined by adding a small amount of La and a needle-like phase forms along the grain boundaries and appropriate La is beneficial to improving the tensile strength and yield strength of the alloy at room temperature. Under 70 MPa and 200 for 100 h the total strain of Mg-8Al-4Sr-1Y-0.05La is 0.13%. ©, 2015, Editorial Office of Transactions of Materials and Heat Treatment. All right reserved.

关键词： Microstructure

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TiCN coating prepared by graphite and carbon black and its wear-resistance

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Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment 2015年第11期36卷 188-193页

作者： Mi, Peng-Bo He, Ji-Ning Yan, Dian-Ran Zhang, Jian-Xin Qin, Yan-Fang School of Materials Science and Engineering Hebei University of Technology Tianjin China Tianjin Key Laboratory of Laminating Fabrication and Interface Control Technology for Advanced Materials Tianjin China

TiCN coating was prepared by reactive plasma spraying with graphite and carbon black as carbon sources. The feeds were studied by the TG-DSC, the constituent phase, microstructure, grain size and wear-resistance of the coatings were analyzed. The results show that TiC0.2N0.8, TiC0.7N0.3phases prepared by carbon black and graphite are dense and the grain size of the coatings are 71.68 nm(TiC0.2N0.8), 59.44 nm(TiC0.7N0.3), respectively. The coatings have higher hardness and wear-resistance, with increasing carbon content, hardness and wear-resistance increase. The wear resistance of the TiC0.7N0.3coating is better than the TiC0.2N0.8coating. © 2015, Editorial Office of TRANSACTIONS OF MATERIALS AND HEAT TREATMENT. All right reserved.

关键词： Wear resistance

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Versatile surface engineering of porous nanomaterials with bioinspired polyphenol coatings for targeted and controlled drug delivery

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Nanoscale 2016年第16期8卷 8600-6页

作者： Juan Li Shuxian Wu Cuichen Wu Liping Qiu Guizhi Zhu Cheng Cui Yuan Liu Weijia Hou Yanyue Wang Liqin Zhang I-Ting Teng Huang-Hao Yang Weihong Tan Key Lab of Analysis and Detection Technology for Food Safety of the MOE Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food Safety College of Chemistry Fuzhou University Fuzhou 350002 P.R. China. hhyang@*** and Molecular Science and Biomedicine Laboratory State Key Laboratory of Chemo/Bio-Sensing and Chemometrics College of Biology and College of Chemistry and Chemical Engineering Hunan University Changsha 410082 China. tan@chem.ufl.edu and Department of Chemistry and Physiology and Functional Genomics Center for Research at the Bio/Nano Interface Health Cancer Center University of Florida Gainesville FL 32611-7200 USA. Key Lab of Analysis and Detection Technology for Food Safety of the MOE Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food Safety College of Chemistry Fuzhou University Fuzhou 350002 P.R. China. hhyang@***. Molecular Science and Biomedicine Laboratory State Key Laboratory of Chemo/Bio-Sensing and Chemometrics College of Biology and College of Chemistry and Chemical Engineering Hunan University Changsha 410082 China. tan@chem.ufl.edu and Department of Chemistry and Physiology and Functional Genomics Center for Research at the Bio/Nano Interface Health Cancer Center University of Florida Gainesville FL 32611-7200 USA. Molecular Science and Biomedicine Laboratory State Key Laboratory of Chemo/Bio-Sensing and Chemometrics College of Biology and College of Chemistry and Chemical Engineering Hunan University Changsha 410082 China. tan@chem.ufl.edu. Department of Chemistry and Physiology and Functional Genomics Center for Research at the Bio/Nano Interface Health Cancer Center University of Florida Gainesville FL 32611-7200 USA.

The development of biocompatible drug delivery systems with targeted recognition and controlled release has experienced a number of design challenges, including, for example, complicated preparation steps and premature drug release. Herein, we address these problems through an in situ self-polymerization method that synthesizes biodegradable polyphenol-coated porous nanomaterials for targeted and controlled drug delivery. As a proof of concept, we synthesized polyphenol-coated mesoporous silica nanoparticles, termed MSN@polyphenol. The polyphenol coatings not only improved colloidal stability and prevented premature drug leakage, but also provided a scaffold for immobilization of targeting moieties, such as aptamers. Both immobilization of targeting aptamers and synthesis of polyphenol coating are easily accomplished without the aid of any other organic reagents. Importantly, the polyphenol coating (EGCg) used in this study could be biodegraded by acidic pH and intracellular glutathione, resulting in the release of trapped anticancer drugs. Based on confocal fluorescence microscopy and cytotoxicity experiments, drug-loaded and polyphenol-coated MSNs were shown to possess highly efficient internalization and an apparent cytotoxic effect on target cancer, but not control, cells. Our results suggest that these highly biocompatible and biodegradable polyphenol-coated MSNs are promising vectors for controlled-release biomedical applications and cancer therapy.

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Rücktitelbild: A Smart Photosensitizer–Manganese Dioxide Nanosystem for Enhanced Photodynamic Therapy by Reducing Glutathione Levels in Cancer Cells (Angew. Chem. 18/2016)

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Angewandte Chemie 2016年第18期128卷

作者： Huanhuan Fan Guobei Yan Zilong Zhao Xiaoxiao Hu Wenhan Zhang Hui Liu Xiaoyi Fu Ting Fu Xiao‐Bing Zhang Weihong Tan Molecular Science and Biomedicine Laboratory State Key Laboratory of Chemo/Bio-Sensing and Chemometrics College of Chemistry and Chemical Engineering College of Biology Collaborative Innovation Center for Chemistry and Molecular Medicine Hunan University Changsha 410082 China Department of Chemistry and Physiology and Functional Genomics Center for Research at the Bio/Nano Interface Shands Cancer Center UF Genetics Institute McKnight Brain Institute University of Florida Gainesville FL 32611-7200 USA

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