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Synthesis, characterization and properties of nanostructured (LaxBa1-x)B6 cathode materials by liquid phase reactive spark plasma sintering

Synthesis, characterization and properties of nanostructured...

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2010 8th International Vacuum Electron Sources Conference and NANOcarbon(第八届真空电子源和纳米碳国际会议)

作者： L.H.Bao Y.F.Wei J.X.Zhang S.L.Zhou R.G.Ma D.M.Liu Q.Z.Huang Key Laboratory of Advanced Functional Materials Ministry of Education College of Materials Science Key Laboratory of Advanced Functional Materials Ministry of Education College of Materials Science Institute of Microstructure and Property of Advanced Materials Beijing University of Technology Be NIST Center for Neutron Research National Institute of Standards and Technology Maryland 20899 US

@@Rare earth hexaboride are excellent thermionic electron cathodes materials with low work function, high emission, high brightness, and a long working time. Light rare earth hexaboride have recently attracted increasing interest due to their applications in electron source of high brightness and longevity [1]. Among these hexaborides, LaB6 was widely investigated for its superior properties. However, the low resistivity (14.2 μΩ cm [2]) of LaB6 is a disadvantage which makes it unsuitable for the direct cathode application, because this increases the heating power. Moreover, the traditional hot sintering method for preparation of LaB6 causes coarse grains and low emission property, which is due to the long sintering time and high temperature. In this paper, we report a study on a liquid phase reactive spark plasma sintering method of fabricating the (LaxBa1-x)B6 compound. Spark plasma sintering (SPS) is a useful method for rapid sintering ceramic nanopowders, and it is suitable for preparation of ultra-fine crystal materials. We substitute the La partly with Ba, and it can be expected that the substitution increases the resistivity. Furthermore, since the radius of Ba is bigger than that of Fe, the substitution can enlarge the lattice constant, and this will decrease the work function.

关键词： X-ray scattering

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Influence of epitaxial growth orientation on residual strain and dielectric properties of (Ba0.3Sr0.7)TiO3 films grown on in-plane compressive substrates

Influence of epitaxial growth orientation on residual strain...

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12th International Meeting on Ferroelectricity, IMF-12 and the 18th IEEE International Symposium on Applications of Ferroelectrics, ISAF-18

作者： Yamada, T. Kamo, T. Su, D. Iijima, T. Funakubo, H. Department of Innovative and Engineered Materials Tokyo Institute of Technology Yokohama 226-8502 Japan Center for Functional Nanomaterials Brookhaven National Laboratory New York 11973 United States Research Center for Hydrogen Industrial Use and Storage National Institute of Advanced Industrial Science and Technology Tsukuba 305-8565 Japan

Orientation dependence of the strain in epitaxial (Ba0.3Sr 0.7)TiO3 films and the dielectric properties have been investigated using in-plane compressive substrates. (100)- and (111)-epitaxial films were grown on (100)- and (111)-cSrRuO3/SrTiO3 substrates by rf magnetron sputtering. The residual strain was found to be remarkably different in those films. The (100)-epitaxial films are fully constrained by the substrate, resulting in the large in-plane compressive strain. On the other hand, the (111)-epitaxial films are almost fully relaxed. As results, for the (100)-epitaxial films, the apparent Curie-Weiss temperature was much higher than that of unstrained bulks. This trend was also confirmed for the films on SrRuO3/(La0.3Sr0.7)(Al 0.65Ta0.35)O3 substrates.

关键词： Titanium oxides

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P1–30: Fabrication of Y2O3-Mo secondary electron emitters by air Plasma Spray method

P1–30: Fabrication of Y2O3-Mo secondary electron emitters b...

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International Conference on Vacuum Electronics

作者： Wei Liu Jinshu Wang Zhiyuan Ren Fan Yang Meiling Zhou Tieyong Zuo The Key Laboratory of Advanced Functional Materials School of Materials Science and Engineering Ministry of Education Beijing University of Technology Beijing China

Rare earth oxide (REO) doped Molybdenum metal ceramic emitters were successfully prepared by the air Plasma Spray (APS) method. Microstructure and secondary electron emission (SEE) performance were investigated. The relative uniform mixing of rare earth oxide and molybdenum have been observed. The maximum secondary electron yield is 3.3 after activation at 1100b(Mo brightness temperature) in vacuum.

关键词： Fabrication Thermal spraying Powders Microstructure Electron emission Plasma materials processing Plasma applications Temperature Cathodes Nuclear and plasma sciences

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In vitro selection of cathepsin E-activity-enhancing peptide aptamers at neutral pH

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International Journal of Peptides 2011年第1期2011卷 834525页

作者： Biyani, Madhu Futakami, Masae Kitamura, Koichiro Kawakubo, Tomoyo Suzuki, Miho Yamamoto, Kenji Nishigaki, Koichi Department of Functional Materials Science Graduate School of Science and Engineering Saitama University Saitama 338-8570 255 Shimo-Okubo Japan City Area Program Saitama Metropolitan Area Saitama Small and Medium Enterprises Development Corporation Chuo-Ku Saitama 338-0001 2-3-2 Kamiochiai Japan Rational Evolutionary Design of Advanced Biomolecules Saitama (REDS) Group Saitama Small Enterprise Promotion Corporation No. 552 Saitama Industrial Technology Center Saitama 333-0844 3-12-18 Kami-Aoki Kawaguchi Japan Janusys Corporation No. 508 Saitama Industrial Technology Center Saitama 333-0844 3-12-18 Kami-Aoki Kawaguchi Japan Proteolysis Research Laboratory Graduate School of Pharmaceutical Sciences Kyushu University Higashi-Ku Fukuoka 812-8582 Japan

The aspartic protease cathepsin E has been shown to induce apoptosis in cancer cells under physiological conditions. Therefore, cathepsin E-activity-enhancing peptides functioning in the physiological pH range are valuable potential cancer therapeutic candidates. Here, we have used a general in vitro selection method (evolutionary rapid panning analysis system (eRAPANSY)), based on inverse substrate-function link (SF-link) selection to successfully identify cathepsin E-activity-enhancing peptide aptamers at neutral pH. A successive enrichment of peptide activators was attained in the course of selection. One such peptide activated cathepsin E up to 260, had a high affinity (KD;300nM), and had physiological activity as demonstrated by its apoptosis-inducing reaction in cancerous cells. This method is expected to be widely applicable for the identification of protease-activity-enhancing peptide aptamers. Copyright © 2011 Madhu Biyani et al.

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Field emission characteristics of polycrystalline LaB6 single tip and surface electric field distribution

Field emission characteristics of polycrystalline LaB6 singl...

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International Vacuum Electron Sources Conference, IVESC

作者： Li-hong Bao Shen-lin Zhou Jiu-xing Zhang Wang Xiao-ju Zu-lun Lin Key Laboratory of Advanced Functional Materials of Education Beijing University of Technology Beijing China School of Optic-Electronic Information University of Electronic Science and Technology of China Chengdu China

Lanthanum hexaboride (LaB 6 ) as an excellent thermionic electron emitter was characterized by high brightness, thermal stability, low volatility and high mechanical strength [1]. The advantages are originated from its low work function (2.4 eV~2.6 eV), high melting point (2715 °C) and covalent bond of B-B atom in crystal structure. Recently, many researchers focused their attention on the excellent field emission properties of LaB 6 one-dimensional nanoelectronics as well as nanomachine applications . Late et al.[3] have reported the LaB 6 tips and foils grown on tungsten and rhenium substrate by Pulsed laser deposition (PLD) at temperature 700°C with average grain size ~ 125nm. However, there are some disadvantages of above-mentioned methods. The BCI 3 as the boron source is easy to absorb water and convert into boric acid, which resist the reaction. The stoichiometry of the products was hard to control by gaseous starting materials. For thin films, there have some intrinsic disadvantages, including poor adhesion to the substrate and oxide contained in the emitter. Compared to the nanowires and nanofilms, the bulk materials can provide large size, low cost, simple preparation. Therefore, there are great research prospects for polycrystalline LaB 6 Field emission properties. The polycrystalline LaB 6 bulk material was prepared by SPS method. The LaB 6 field emitting single tip has been achieved using the electrochemical etching method. Figure 1 shows the relative density of 95.5% and 99.2% corrosion morphology. It is seen from the figure 1 that the low-density samples have a large number of corrosion holes and surface defects, showing anisotropic corrosion characteristic. This is due to the corrosion process, the etching solutions immerse to the holes to lateral erosion, which directly led to the tip radius of about 10μm. The relative density of 99.2% of tip shows that corrosion of the sample is uniform and surface is smooth, the tip radius is about 2μm. Fig.

关键词： Educational institutions

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The synthesis and optical properties of ZnO nanocombs

The synthesis and optical properties of ZnO nanocombs

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作者： Zang, C.H. Liu, Y.C. Zhao, D.X. Zhang, J.Y. Shen, D.Z. Key Laboratory of Excited State Process Changchun Institute of Optics Fine Mechanics and Physics Chinese Academy of Sciences Changchun 130033 China Center for Advanced Optoelectronic Functional Materials Research Northeast Normal University Changchun 130024 China Department of Mathematics and Physics Luoyang Institute of Science and Technology Luoyang 471023 China

The ZnO nanocombs were synthesized by chemical vapor deposition method, which the uniform and dense nanotips were along one side of the comb ribbon. The growth mechanism was described as free catalyst self-assembled and vapor-solid model. The optical properties related with the surface states were investigated by Raman and PL spectra. The large redshift of 1LO phonon peak was attributed to the surface and interface states. The normalized PL spectra showed that the deep-level emission decreased for the sample to be annealed in O2 ambient at 500 °C. On the contrary, the deep-level emission increased while for the annealed sample in O2 ambient at 600 7deg;C. The deeplevel emission was attributed to the transition from the shallow donor to the deep acceptor. The XPS analysis showed the existence of oxygen rich and Zn deficient in the ZnO nanocombs annealed at 600 °C. The abnormal temperature dependence of Integrated PL intensity was attributed to the abundant surface states. Copyright © 2010 American Scientific Publishers All rights reserved.

关键词： Zinc oxide

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Evaluation of bias of the influx constant estimated by Patlak analysis for [18F]FDOPA PET: Influence of metabolites for [18F] FDOPA

Transactions of Japanese Society for Medical and Biological ...

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Transactions of Japanese Society for Medical and Biological Engineering 2010年第1期48卷 66-74页

作者： Matsubara, Keisuke Watabe, Hiroshi Hayashi, Takuya Minato, Kotaro Iida, Hidehiro Graduate School of Information Science Nara Institute of Science and Technology Japan Department of Investigative Radiology Advanced-Medical Engineering Center National Cardiovascular Center Japan Functional Probe Research Laboratory RIKEN Center for Molecular Imaging Science Japan

Patlak analysis, which estimates the net FDOPA influx constant (Ki by linear regression of data acquired from [18F] FDOPA PET study, is widely employed in the diagnosis of neurological disorder, such as Parkinson's disease. In K estimation by Patlak analysis, it is assumed that the metabolites of radioligand do not diffuse out of the tissue during PET scan. However, [ 18F] F-Dopamine, synthesized from [18F] FDOPA, is rapidly metabolized and its metabolites diffuse from the tissue. We aimed at the evaluation of the effect of dopamine metabolism and the clearance of its metabolites on K estimated by Patlak analysis. For this purpose, we developed a model describing the detailed pathway of dopamine kinetics in the striatum, and a standard timeactivity curve (TAC) was generated based on this model and [ 18F] FDOPA PET data of a monkey. And TACs in case of altering the dopamine metabolism or the clearance of its metabolites were ***, we evaluated K1, values estimated by Patlak analysis for these simulated TACs. K was increased when the dopamine metabolism to DOPAC (κ dopac9) and the clearance of DOPAC and HVA (AfTc, k\?) were altered. The results suggest that K could be biased by the influence of the metabolism of dopamine and clearance of its metabolites. Therefore, it is important to consider these biases in the interpretation of K value estimated Patlak analysis.

关键词： Metabolites

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Unprecedented Stability of a Photochromic Bisthienylethene Based on Benzobisthiadiazole as an Ethene Bridge†

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Angewandte Chemie 2011年第46期123卷

作者： Weihong Zhu Yuheng Yang Rémi Métivier Qiong Zhang Régis Guillot Yongshu Xie He Tian Keitaro Nakatani Shanghai Key Laboratory of Functional Materials Chemistry Key Laboratory for Advanced Materials and Institute of Fine Chemicals East China University of Science & Technology Shanghai 200237 (China) PPSM ENS Cachan CNRS UniverSud 61 av Président Wilson 94230 Cachan (France) Institut de Chimie Moléculaire et des Matériaux d'Orsay UMR8182 CNRS Université Paris‐Sud Bât 420 91405 Orsay Cedex (France)

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Influence of Different Conditions of Initiators on Grafting Ratio

Influence of Different Conditions of Initiators on Grafting ...

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作者： Hui-Cai Shi Zan-Min Wu Zhan-Zhu Zhang Su-Wan Zhang School of Textiles Key Laboratory of Advanced Textile CompositesMinistry of EducationTianjin Polytechnic University Department of Textile and Garments Hebei University of Science and Technology MEKL of Advanced Textile Composite Materials Institute of Textile CompositesTianjin Polytechnic University

There are mainly starch,PVA and polyacrylic size used as sizing materials in textile warp *** size cannot be used as the main body *** PVA is of excellent size,it is difficult to biodegrade and also pollutes environmental *** graft copolymer can replace PVA because it has excellent sizing and biodegradable *** starch graft is the very hopeful kind of *** starch graft product has been quite common in other domain applications,but as a textile size is still in the research *** far,the studies on starch graft have mainly focused on the development and selection of the initiators,since initiator is the key agent to activate the reaction of copolymerization ***,experiments were conducted to screen appropriate *** means of single factor test,initiator concentration and temperature affecting the grafting ratio of the polymerization reaction were thoroughly investigated.[Mn(H2P2O7)3]3-was finally validated to be the best initiator for the starch grafted with acrylic amide.

关键词： size starch graft copolymer initiator initiator concentration temperature grafting ratio

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Synthesis of graphene on a polycrystalline Co film by radio-frequency plasma-enhanced chemical vapour deposition

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Journal of Physics D: Applied Physics 2010年第45期43卷

作者： Wang, S.M. Pei, Y.H. Wang, X. Wang, H. Meng, Q.N. Tian, H.W. Zheng, X.L. Zheng, W.T. Liu, Y.C. Department of Materials Science Key Laboratory of Mobile Materials Jilin University Changchun 130012 China Center for Advanced Optoelectronic Functional Materials Research Key Laboratory for UV-Emitting Materials and Technology of Ministry of Education Northeast Normal University 5268 Renmin Street Changchun 130024 China

Graphene of 1-5 layers was synthesized on a polycrystalline Co film by radio-frequency plasma-enhanced chemical vapour deposition at a relatively low temperature of 800 °C for only 40 s in a mixture of gases of CH 4/H2/Ar (1/5/20, with a total gas flow rate of 78 sccm). The obtained graphene is of high quality as revealed by Raman spectroscopy and x-ray photoelectron spectroscopy. It exhibits a high optical transmittance of more than 70% in the wavelength range 500-1200 nm, and a sheet resistivity of 2661 Ω/sq. A possible formation mechanism is proposed. The significant influence of octahedral and tetrahedral lattice interstitial sites in the Co crystallites on the formation of graphene is discussed. © 2010 IOP Publishing Ltd.

关键词： Graphene

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