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Eu3+activated GaN thin films grown on sapphire by pulsed laser deposition

physica status solidi c 2008年第6期5卷

作者： Nestor Perea-Lopez Jonathan H. Tao Joanna McKittrick Jan B. Talbot M. Raukas J. Laski K. C. Mishra Gustavo Hirata Materials Science and Engineering Program University of California at San Diego La Jolla CA 92093 USA Department of Mechanical and Aerospace Engineering University of California at San Diego La Jolla CA 92093 USA Department of Nanoengineering University of California at San Diego La Jolla CA 92093 USA OSRAM SYLVANIA Central Research Beverly MA 01915-1068 USA CCMC-UNAM Km. 107 Carretera Tijuana-Ensenada C. P. 22800 Ensenada Baja California México

By means of pulsed laser deposition, polycrystlline thin films of GaN doped with Eu 3+ were grown on sapphire. The PLD target was formed in three steps. First, stoichiometric amounts of Ga 2 O 3 and Eu 2 O 3 were dissolved in nitric acid, which produces Ga (1– x ) Eu x (NO 3 ) 3 . Next, the nitrates were oxidized in a tubular furnace with O 2 flow forming Ga 2(1– x ) Eu 2 x O 3 . Finally, the oxide powder was flushed with anhydrous ammonia to produce the desired nitride product: Ga (1– x ) Eu x N. Film growth was done in a stainless steel vacuum chamber partially filled with N 2 (400 mTorr). For the deposit, the 3 rd harmonic of a Nd:YAG laser ( λ = 355 nm) was focused on the surface of the target. After deposition, annealing in NH 3 was required to produce films with pure GaN hexagonal phase. The luminescence of the film was characterized by photo- and cathodoluminescence. In addition, the chemical and structural properties were analyzed by X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

关键词： 61.05.cp 68.37.Hk 68.55.−a 78.55.Cr 78.60.Hk 81.15.Fg

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High temperature corrosion of materials in supercritical water and liquid lead-alloy environments

High temperature corrosion of materials in supercritical wat...

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Interfacial Electrochemistry and Chemistry in High Temperature Media - 212th ECS Meeting

作者： Sridharan, K. Chen, Y. Tan, L. Machut, M. Kruizenga, A. Ren, X. Allen, T.R. Department of Engineering Physics University of Wisconsin Madison United States Materials Science Program University of Wisconsin Madison United States

ISBN: (纸本)9781605603124

The Supercritical Water-cooled Reactor (SCWR) and Lead-cooled Fast Reactor (LFR) are among the six reactor concepts identified by the Generation IV initiative for the next generation nuclear reactors. materials degradation due to corrosion is a significant issue in both supercritical water and molten lead (-alloy) environments, particularly at the intended higher temperatures of application. In supercritical water, corrosion of ferritic and austenitic steels and Inconel alloys occurs mainly by the growth of an oxide layer on the surface. In molten lead (-alloy), corrosion can occur by dissolution of the material, oxidation, or by the penetration of liquid metal into the material primarily along the grain boundaries. Surface treatment of ferritic steels by the incorporation of thin film of oxidation-resistant materials has been shown to mitigate corrosion in these aggressive environments. Grain boundary engineering (GBE) reduces spallation of oxide layers in austenitic steels in supercritical water environment. © The Electrochemical Society.

关键词： Ferrite

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Macromol. Mater. Eng. 2/2008

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Macromolecular materials and engineering 2008年第2期293卷

作者： Atheer Almasri Zoubeida Ounaies Yeon Seok Kim Jaime Grunlan Aerospace Engineering Department 3141 TAMU Texas A&M University College Station TX 77843 USA Materials Science and Engineering Program 3141 TAMU Texas A&M University College Station TX 77843 USA Mechanical Engineering Department 3141 TAMU Texas A&M University College Station TX 77843 USA

Cover: The picture illustrates that the addition of dual wall carbon nanotubes (DWNTs) to PVDF leads to stable solutions, which results in nanocomposite films with good dispersion, and improved mechanical, electrical, dielectric and electromechanical properties as compared to the pure PVDF. These property enhancements may open the way to the development of improved piezoelectric materials for sensors and actuators. Further details can be found in the article by A. Almasri, Z. Ounaies, * Y. S. Kim, and J. Grunlan on page 123.

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Silk fibroin membranes from solvent-crystallized silk fibroin/gelatin blends: Effects of blend and solvent composition

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materials science and engineering C 2007年第3期27卷 426-431页

作者： Gil, Eun S. Frankowski, David J. Hudson, Samuel M. Spontak, Richard J. Fiber and Polymer Science Program North Carolina State University Raleigh NC 27695 United States Department of Chemical and Biomolecular Engineering North Carolina State University Raleigh NC 27695 United States Department of Materials Science and Engineering North Carolina State University Raleigh NC 27695 United States

Protein membranes have been prepared by mixing gelatin (G) with Bombyx mori silk fibroin (SF) and using aqueous methanol (MeOH) to induce SF crystallization. Amorphous blends of these polymers appear quasi-homogeneous, as discerned from visual observation, electron microscopy and Fourier-transform infrared (FTIR) spectroscopy. Upon subsequent exposure to aqueous MeOH, SF undergoes a conformational change from random-coil to β-sheet. This transformation occurs in pure SF, as well as in each of the G/SF blends, as discerned from FTIR spectroscopy and thermal calorimetry. The influence of MeOH-induced SF crystallization on structure and property development has been measured as functions of blend and solvent composition. By preserving a support scaffold above the G helix-to-coil transition temperature, the formation of crystalline SF networks in G/SF blends can be used to stabilize G-based hydrogels or generate SF membranes for biomaterial, pharmaceutical and gas-separation purposes. The present study not only examines the properties of G/SF blends before and after SF crystallization, but also establishes the foundation for future research into thermally-responsive G/SF bioconjugates. © 2006 Elsevier B.V. All rights reserved.

关键词： Membranes

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Boron coating to combat corrosion and oxidation

Boron coating to combat corrosion and oxidation

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作者： Petrova, Roumiana S. Suwattananont, Naruemon Pallegar, Kranthi K. Vangaveti, Raghasudha Materials Science and Engineering Program Physics Department New Jersey Institute of Technology University Heights Newark NJ 07102 United States

The present study describes the recent investigation of boronized surface coating on Steel, Ni super alloy and pure Tantalum. The coatings were produced by thermo-chemical treatment with an original technology powder mixture at the temperature range of 850-1050°C. Metallographic examination, X-ray diffraction (XRD) and microhardness testing were used to determine the characteristics of the diffusion layer compared with the substrate. The continuous weighting method and the potentiodynamic polarization measurements were used to investigate the corrosion resistance of the specimen surface before and after boronizing. Also, the high temperature oxidation method detected by differential thermal analysis (TGA) was used to observe the oxidation resistance of unboronized and boronized specimens. It was shown that the boronizing process created a boride layer with a thickness of 10-80 μm depending on substrates, temperatures, and times, with microhardness of about 8-10 times greater than that of the substrate. The corrosion resistance of the boronized coating was determined to be 6-10 times higher than that of the substrate. As well, the oxidation resistance of the boronized coating was 3-5 times better than that of the substrate.

关键词： Protective coatings

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Microscale bioengineering inspired by nature: From widgets to cell biology

Microscale bioengineering inspired by nature: From widgets t...

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29th Annual International Conference of IEEE-EMBS, engineering in Medicine and Biology Society, EMBC'07

作者： Beebe, David J. Biomedical Engineering University of Wisconsin Madison United States Department of Biomedical Engineering University of Wisconsin Madison United States Stem Cell Program Materials Science Program UW Comprehensive Cancer Center

No abstract available

ISBN: (纸本)1424407885

No abstract available

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Abstracts for the 6th Congress of Asian Sleep Research Society

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Sleep and Biological Rhythms 2009年第4期7卷 A1-A49页

作者： Seog Ju Kim In Kyoon Lyoo Yu-Jin Lee Do-Un Jeong Hirohiko Kanai Masanori Ookubo Atsushi Yoshimura Masako Okawa Noto Yamada Takeshi Munezawa Yoshitaka Kaneita Yoneatsu Osaki Hideyuki Kanda Tadahiro Ohtsu Masumi Minowa Kenji Suzuki Susumu Hijuchi Hiroyuki Suzuki Takashi Ohida Takashi Abe Yoko Komada Shoichi Asaoka Yuichi Inoue Jin-Seong Lee Sang-Yong Cho Deependra Kumar Hruda N. Mallick Velayudhan M. Kumar Mahesh K. Kaushik Akihiro Karashima Noiihiro Katayama Mitsuyuki Nakao Ravindra P. Nagendra Sathiamma Sulekha Sathyaprabha T. Narasappa Pradhan Nityanadan Bindu M. Kutty M. Nirmala P. N. Ravindra Basavaraj Ramappa Tubaki T. N. Sathyaprabha D. Sudhakar G. S. Lavekar C. R. Chandrashekar Kazuyoshi Kitaoka Mika Shimizu Sachiko Chikahisa Kazuo Yoshizaki Hiroyoshi Sei Jong-Won Kim Misa Takegami Shin Yamazaki Yasuaki Hayashino Rei Ono Koji Otani Miho Sekiguchi Shinichi Konno Shunichi Fukuhara Antonia J. Jakobson Paul Fitzgerald Russell Conduit Xin Shirley Li Siu Ping Joyce Lam Wai Man Mandy Yu Yun Kwok Wing Kazue Okamoto-Mizuno Koh Mizuno Mituaki Yamamoto Shuichiro Shirakawa Hirokazu Doi Mikako Kato Kazuyuki Shinohara Masako Tamaki Shiori Matsuda Katsuo Yamazaki Tadao Hori Keiko Ogawa Kazumi Takahashi Kunio Kitahama Katuo Yamazaki Yoshimasa Koyama Kohei Shioda Yugo Ueda Yukiko Nakamura Clara Inoue Kazushige Goto Sunao Uchida Yuko Morita Yoshiko Honda Tohru Kodama Mari Hagihara Toru Nakajima Masato Saito Yoshihiko Koga Shinichiro Tanaka Hiroshi Yamadera Madoka Takahara Sachiko Suwa Minoru Onozuka Sadao Sato Fumiharu Togo Taiki Komatsu Takeshi Mitani Jongbae Choi Bin Zhang Taeko Sasai Hiromi Mitsubayashi Mitsuhiro Ohtsu Isao Hasegawa Tatsuya Ishii Akira Komori Asami Suzuki Yue Nakahara Mitsuyasu Hiroki Mariko Nakauma Nobuo Someya Tomomasa Ochiai Shouhei Komori Rayleigh Ping-Ying Chiang Zai-Ting Yeh Seong T. Kim Seung H. Yoon Jeong S. Kwon Jong H. Choi Hyung J. Ahn Youngsoo Kim Bolortuya Yunren Lichao Chen Radhika Basheer Robert W. Mccarley Robert E. Strecker Makoto Honda Tetsuaki Arai Miyuki Fukazawa Yutaka Honda Kuniaki T Department of Psychiatry Gachon University of Medicine and Science Incheon Republic of Korea Department of Psychiatry Seoul National University Seoul Republic of Korea Department of Neuropsychiatry and Center for Sleep and Chronobiology Seoul National University Hospital Seoul Republic of Korea Department of Neuropsychiatry Seoul National University Hospital Seoul Republic of Korea Seoul National University Hospital Seoul Republic of Korea Department of Psychiatry Shiga University of Medical Science Otsu Japan Division of Public Health Department of Social Medicine Nihon University School of Medicine Tokyo Japan Department of Public Health Nihon University School of Medicine Tokyo Japan Division of Environmental and Preventive Medicine Department of Social Medicine Faculty of Medicine Tottori University Yonago Japan Department of Hygiene and Preventive Medicine Fukushima Medical University Fukushima Japan Department of Public Health Showa University School of Medicine Tokyo Japan Faculty of Humanities Seitoku University Matsudo Japan Section on Behavioral Science Division of Clinical Research National Hospital Organization Kurihama Alcoholism Center Yokosuka Japan Department of Otolaryngology Second Hospital Fujita Health University Nagoya Japan National Hospital Organization Kurihama Alcoholism Center Kanagawa Japan Metropolitan Police Department Criminal Investigation Laboratory Tokyo Japan Japan Somnology Center Neuropsychiatrie Research Institute Tokyo Japan Department of Somnology Tokyo Medical University Tokyo Japan Japan Somnology Center Neuropsychiatric Research Institute Tokyo Japan Department of Somnology Tokyo Medical and Dental University Tokyo Japan Center for Sleep and Chronobiology Department of Psychiatry and Behavioral Science Seoul National University College of Medicine Seoul Republic of Korea Department of Psychiatry and Behavioral Science Center for Sleep and Chronobiology Seoul Republic of Korea Department of Physiology Al

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X-Ray Diffuse Scattering Measurements of Nucleation Dynamics at Femtosecond Resolution

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Physical Review Letters 2008年第13期100卷 135502-135502页

作者： A. M. Lindenberg S. Engemann K. J. Gaffney K. Sokolowski-Tinten J. Larsson P. B. Hillyard D. A. Reis D. M. Fritz J. Arthur R. A. Akre M. J. George A. Deb P. H. Bucksbaum J. Hajdu D. A. Meyer M. Nicoul C. Blome Th. Tschentscher A. L. Cavalieri R. W. Falcone S. H. Lee R. Pahl J. Rudati P. H. Fuoss A. J. Nelson P. Krejcik D. P. Siddons P. Lorazo J. B. Hastings PULSE Center Stanford Linear Accelerator Center Menlo Park California 94025 USA Stanford University Department of Materials Science and Engineering Stanford California 94305 USA Stanford Synchrotron Radiation Laboratory/SLAC Menlo Park California 94025 USA* Institut für Experimentelle Physik Universität Duisberg-Essen D-45117 Essen Germany Department of Physics Lund Institute of Technology P.O. Box 118 S-22100 Lund Sweden Department of Chemistry Stanford University Stanford California 94305 USA FOCUS Center Department of Physics and Applied Physics Program University of Michigan Ann Arbor Michigan 48109 USA Stanford Linear Accelerator Center Menlo Park California 94025 USA Department of Cell and Molecular Biology Biomedical Centre Uppsala University SE-75124 Uppsala Sweden Stanford University Department of Chemistry Stanford California 94305 USA Deutsches Elektronen-Synchrotron DESY Notkestrasse 85 22607 Hamburg Germany Max-Planck-Institute of Quantum Optics Hans-Kopfermann-Str. 1 D-85748 Garching Germany Department of Physics University of California Berkeley California 94720 USA Length/Time Metrology Group Korea Research Institute of Standards and Science Daejeon 305-600 Republic of Korea Consortium for Advanced Radiation Sources The University of Chicago Chicago Illinois 60637 USA Advanced Photon Source Argonne National Laboratory Argonne Illinois 60439 USA Materials Science Division Argonne National Laboratory Argonne Illinois 60439 USA Physics Department Lawrence Livermore National Laboratory Livermore California 94550 USA National Synchrotron Light Source Brookhaven National Laboratory Upton New York 11973 USA Departement de Genie Physique Ecole Polytechnique de Montreal C.P. 6079 Succursale Centre-Ville Montreal (Quebec) Canada H3C 3A7

Femtosecond time-resolved small and wide angle x-ray diffuse scattering techniques are applied to investigate the ultrafast nucleation processes that occur during the ablation process in semiconducting materials. Following intense optical excitation, a transient liquid state of high compressibility characterized by large-amplitude density fluctuations is observed and the buildup of these fluctuations is measured in real time. Small-angle scattering measurements reveal snapshots of the spontaneous nucleation of nanoscale voids within a metastable liquid and support theoretical predictions of the ablation process.

关键词： Ultrashort pulses

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Fabrication and immobilization of 2D colloidal photonic crystals

Fabrication and immobilization of 2D colloidal photonic crys...

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ASME 2007 International Mechanical engineering Congress and Exposition, IMECE 2007

作者： Asmatulu, Ramazan Kim, Sejong Bright, Robin R. Papadimitrakopoulos, Fotis Marcus, Harris Department of Mechanical Engineering Wichita State University 1845 Fairmount WichitaKS67260-0133 United States Institute of Materials Science Materials Science and Engineering Program Nanomaterials Optoelectronics Laboratory University of Connecticut StorrsCT06269-3136 United States

ISBN: (纸本)079184305X

A dielectrophoretic, DEP, force induced assembly technique was used to achieve close-packed 2D colloidal photonic crystals on a substrate. The experimental tests were conducted on 5.3 μm carboxyl fictionalized polystyrene (PS) particles at a 6 AC Voltage and 1 MHz frequency. After the crystal was completely formed at the center of electrodes, a polyacrylamide solution was added to the system to immobilize the photonic crystals. Copyright © 2007 by ASME.

关键词： Electrophoresis

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Nanoscale zirconium tungstate synthesis and use as a filler for dimensional stability

Nanoscale zirconium tungstate synthesis and use as a filler ...

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SAMPE '07: M and P - From Coast to Coast and Around the World

作者： Schnabel, Steven L. Cross, William M. Kellar, Jon J. Kjerengtroen, Lidvin Welsh, Jeffrey South Dakota School of Mines and Technology Materials Engineering and Science Program 501 E. St. Joseph St. Department of Materials and Metallurgical Engineering 501 E. St. Joseph St. Department of Mechanical Engineering Air Force Research 501 E. St. Joseph St.

ISBN: (纸本)1934551007

Previous research by our group has shown that addition of an isotropic negatively thermal expanding material to a polymer results in a matrix with near dimensionally stable properties. Eshelby models have shown the morphology of the filler material can affect the overall composite coefficient of thermal expansion. Toward this end, particle shape control of zirconium tungstate (ZrW2O8) has been examined by reverse phase microemulsion synthesis. Diffraction patterns clearly indicate formation of 65-100% crystalline zirconium tungstate with remaining traces of tungsten oxide (WO 3). Parallelepiped shaped particles having face-side lengths of ∼100-200 nanometers and lengths of one to three microns were found. The size of the resulting particles is smaller compared to those of sol-gel processing techniques, which have also been evaluated. The details associated with the preparation of this filler will be reported as well as the affect of different surfactants and temperature on the particle morphology and size. Finally, the nanoscale zirconium tungstate filler was incorporated into a polymer matrix and the composite coefficient of thermal expansion determined as a function of temperature.

关键词： Zirconium compounds

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