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The effects of process parameters on size, density, structure, and field emission properties of Pd-catalyzed carbon nanotubes synthesized by thermal chemical vapor deposition

The effects of process parameters on size, density, structur...

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International Conference on Vacuum Nanoelectronics (IVNC)

作者： S. Wei W.P. Kang W.H. Hofmeister J.L. Davidson Y.M. Wong J.H. Huang Interdisciplinary Graduate Program in Material Science Vanderbilt University Nashville TN USA Department of Electrical Engineering and Computer Science Vanderbilt University Nashville TN USA Department of Chemical Engineering Vanderbilt University Nashville TN USA Department of Materials Science and Engineering National Tsing Hua University Hsinchu Taiwan

In this study, various thicknesses of Pd catalytic films were deposited on Ti/Si substrates and pretreated with NH/sub 3/. The effects of catalyst deposition parameters and NH/sub 3/ pretreatment time (0, 1, and 10 minutes) on the size distribution of Pd catalytic particles, and subsequently, on the diameter and density of synthesized carbon nanotubes (CNTs) were investigated. The CNTs were synthesized by thermal CVD at 750/spl deg/C using methane (CH/sub 4/) as the carbon source, and a mixture of Ar/H/sub 2/ (80 vol.%/20 vol.%) as the carrier gas.

关键词： Carbon nanotubes Chemical vapor deposition Argon Hydrogen Scanning electron microscopy Morphology Substrates materials science and technology Transmission electron microscopy Carbon dioxide

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Transistor characteristics of thermal CVD carbon nanotubes field emission triode

Transistor characteristics of thermal CVD carbon nanotubes f...

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International Conference on Vacuum Nanoelectronics (IVNC)

作者： Y.M. Wong W.P. Kang J.L. Davidson W. Hofmeister S. Wei J.H. Huang Dept. of Electrical Engineering and Computer Science Vanderbilt Univ. Nashville TN USA Interdisciplinary Graduate Program in Material Science Vanderbilt Univ. Nashville TN USA Dept. of Materials Science and Engineering National Tsing Hua Univ. Hsinchu Taiwan ROC

In this paper, the study of thermal CVD grown CNT field emitters in a triode amplifier configuration is reported. The DC characteristics of the CNT triode are investigated, including I/sub a/ vs. V/sub a/ for different V/sub g/. Moreover, DC parameters such as transconductance, amplification factor and anode resistance of the triode amplifier are determined. It was shown that a higher amplification factor can be achieved with optimum gate-anode-cathode spacing such that the cathode is effectively shielded from the anode by the gate but the anode still collects all electrons emitted from the cathode. High emission current at low gate voltage is key to achieving high transconductance. This can be obtained by optimum configuration of high-density CNTs array in a triode structure with a common gate.

关键词： Carbon nanotubes Voltage Anodes materials science and technology Current measurement Palladium Silicon Furnaces Temperature Cathodes

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Effects of Surface Roughness and Maximum Load on the Mechanical Properties of Cancellous Bone Measured by Nanoindentation

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MRS Online Proceedings Library 2004年第1期823卷 W8.5.1-W8.5.6页

作者： Donnelly, Eve Baker, Shefford P. Boskey, Adele L. van der Meulen, Marjolein C. H. Sibley School of Mechanical and Aerospace Engineering Cornell University Ithaca USA Department of Materials Science and Engineering Cornell University Ithaca USA Musculoskeletal Integrity Program Hospital for Special Surgery New York USA Department of Biochemistry Weill Medical College of Cornell University New York USA Graduate Program in Physiology Biophysics and Systems Biology Weill Medical College of Cornell University New York USA

Nanoindentation was used to assess the mechanical properties of lamellar and interlamellar tissue in dehydrated rabbit cancellous bone. The effects of surface roughness and maximum nanoindentation load on the measured mechanical properties were examined in two samples of differing surface roughness using maximum loads ranging from 250-3000 μN. As the ratio of indentation depth to surface roughness decreased below approximately 3:1, the variability in material properties increased substantially. At low loads, the indentation modulus of the lamellar bone was approximately 20% greater than that of the interlamellar bone, while at high loads the measured properties of both layers converged to an intermediate value. Relatively shallow indentations made on smooth surfaces revealed significant differences in the properties of lamellar and interlamellar bone that are consistent with microstructural observations of lamellar bone as more mineralized than interlamellar bone.

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Pressure, Temperature, and Thickness Dependence of CO2-Induced Devitrification of Polymer Films

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Physical Review Letters 2003年第17期91卷 175503-175503页

作者： Joseph Q. Pham Stephen M. Sirard Keith P. Johnston Peter F. Green Graduate Program in Materials Science and Engineering University of Texas at Austin Austin Texas 78712 USA Department of Chemical Engineering and Texas Materials Institute University of Texas at Austin Austin Texas 78712 USA

The glass transition temperature is known to increase with decreasing film thickness h for sufficiently thin poly(methyl methacrylate) films supported by silicon oxide substrates. We show that this system undergoes a CO2 pressure-induced devitrification transition, Pg, which is film thickness dependent, Pg(h)=ΔPg+Pgbulk. Pgbulk is the bulk glass transition and ΔPg can be positive or negative depending on T and P. The phenomenon of retrograde vitrification, wherein the polymer exhibits a rubbery-to-glassy-to-rubbery transition upon changing temperature isobarically, is also shown to occur in this system and it is film thickness dependent.

关键词： Polymethyl methacrylates

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Optimization of DNA microsensor arrays for biological detection

Optimization of DNA microsensor arrays for biological detect...

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ASME 2000 International Mechanical engineering Congress and Exposition, IMECE 2000

作者： Gau, Jen-Jr Lan, Esther H. Dunn, Bruce Ho, Chih-Ming Biomedical Engineering Interdepartmental Graduate Degree Program University of California Los Angeles United States Department of Materials Science and Engineering University of California Los Angeles United States Department of Mechanical and Aerospace Engineering University of California Los Angeles United States

ISBN: (纸本)9780791819005

This paper describes the characterization and optimization of a reusable DNA microsensor array for rapid biological agent detection developed in previous publications. (Fig.l) [1-3] This MEMS based DNA sensor utilizes a standard three-electrode electrochemical cell configuration with novel micro fabricated structure design to minimize non-specific binding. The sensor module is easily to be adapted to various protocols and can be used for rapid detection of macromolecules (DNA, RNA) from targets such as uropathogenic Escherichia coli (E. coli) in urine and microorganisms causing otitis media (middle ear infection). Less than 105 E. coli cells can be detected from the urine sample of a patient with urine tract infection. The sensitivity is enhanced by appropriate sensor characterization and surface modification. The total detection time including sample preparation can be reduced to 25 minutes by using a POD conjugated oligonucleotide. Copyright © 2000 by ASME

关键词： DNA

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engineering the environmentally sound warship for the twenty-first century

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NAVAL ENGINEERS JOURNAL 1999年第3期111卷 189-217页

作者： Markle, SP Gill, SE McGraw, PS Udr. Stephen P. Markle USN is a career Engineering Duty officer assigned to Naval Sea Systems Command Arlington Virginia where he is Deputy Directs Environmental Programs Division (SEA 03L1 B). He is responsible fm program management activities associated with all ahat environmental protection equipment design and selection of environmental protection equipment and systems fm future surface ship designs (DD 21 CVN 7Z CW LPD 17) and serves on several teams designed to promote Nay wide awarmss of environmental protection requirements and Nay programs to meet these challenges. He is a 1993 graduate of the Naval Construction and Engineering Program at the Massachusetts Institute of Technology where he received a naval engineers degree and master of science in mechanical engineering. His interest in environmental issues predates his undergraduate studies at Syracuse Universityl State University of New Ymk College of Environmental Science and Fmestry where he received a bachelm of science degree in fmest engineering from the School of Environmental and Resource Engineering. LCdx Markle has qualified as a Surface Warfare Officer and in submarines through the Engineering Duty Dolphin Program he is a member of the Acquisition Professional Community and a graduate of the Defense Systems Management College Advanced Program Managers Course. He is a professional engineer registered in the State of New York and is a member ofthe American Society of Naval Engineers National Society of Professional Engineers American Society for Testing and Materials Society of Naval Architects and Marine Engineers and Society of Automotive Engineers. Peter 5. McGraw is current the Acting Branch Head ofthe Solid Waste Management Branch (Code 634) of the Environmental Quality Dwrtment of the Naval Surfice Warfare Centel: Carderock Division. As such he is responsible for among other things: the Shipboard Advanced Incinerator RDT&E Program the Submarine Plastic Waste RDT&E Program Solid Waste Processing Equipment Design Acquisitio

The past twenty-five years has been marked by the introduction ed marine environmental regulations that have had a profound effect on how ships are designed, built and operated. Ships being designed and built today must accommodate not only current regulations but anticipate those enacted over their thirty to fifty year life cycles. U.S. Chief of Naval Operations, Office of Environmental, Safety and Health (CNO N45) has articulated a vision for the Environmentally Sound Warship of the Twenty-first Century. This vision incorporates the "Sense of Congress" for a naval ship designed to operate in full compliance with environmental regulations worldwide. The task of the Navy engineering team is to translate this vision into reality;a ship capable of prevailing in time of war and able to conduct operations in all areas of the globe, unencumbered by special procedures for environmental compliance. The keys to this warship design are the early integration of environmentally sound principles, materials, and processes into the ship acquisition process;minimization of both hazardous materials and generation of post shipboard consumer waste during operation;adaptation of integrated systems to reduce the volume of wastes and enhance processing efficiency;reduced manpower requirements;and crew indoctrination in environmental protection.

关键词： Ships Environmental regulations engineering ARTICULATED Navy environmental security

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Contributory presentations/posters

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Journal of Biosciences 1999年第1期24卷 33-198页

作者： N. Manoj V. R. Srinivas A. Surolia M. Vijayan K. Suguna R. Ravishankar R. Schwarzenbacher K. Zeth Diederichs G. M. Kostner A. Gries P. Laggner R. Prassl Madhusudan Pearl Akamine Nguyen-huu Xuong Susan S. Taylor M. Bidva Sagar K. Saikrishnan S. Roy K. Purnapatre P. Handa U. Varshney B. K. Biswal N. Sukumar J. K. Mohana Rao A. Johnson Vasantha Pattabhi S. Sri Krishna Mira Sastri H. S. Savithri M. R. N. Murthy Bindu Pillai Kannan M. V. Hosur Mukesh Kumar Swati Patwardhan K. K. Kannan B. Padmanabhaa S. Sasaki-Sugio M. Nukaga T. Matsuzaki S. Karthikevan S. Sharma A. K. Sharma M. Paramasivam P. Kumar J. A. Khan S. Yadav A. Srinivasan T. P. Singh S. Gourinath Neelima Alam A. Srintvasan Vikas Chandra Punit Kaur Ch. Betzel S. Ghosh A. K. Bera S. Bhattacharya S. Chakraborty A. K. Pal B. P. Mukhopadhyay I. Dey U. Haldar Asok Baneriee Jozef Sevcik Adriana Solovicova K. Sekar M. Sundaralingam N. Genov Dong-cai Liang Tao Jiang Ji-ping Zhang Wen-rui Chang Wolfgang Jahnke Marcel Blommers S. C. Panchal R. V. Hosur Bindu Pillay Puniti Mathur S. Srivatsun Ratan Mani Joshi N. R. Jaganathan V. S. Chauhan H. S. Atreya S. C. Sahu K. V. R. Chary Girjesh Govil Elisabeth Adjadj Éric Quinjou Nadia Izadi-Pruneyre Yves Blouquit Joël Mispelter Bernadette Heyd Guilhem Lerat Philippe Milnard Michel Desmadreil Y. Lin B. D. Nageswara Rao Vidva Raghunathan Mei H. Chau Prashant Pesais Sudha Srivastava Evans Coutinho Anil Saran Leizl F. Sapico Jayson Gesme Herbert Lijima Raymond Paxton Thamarapu Srikrishnan C. R. Grace G. Nagenagowda A. M. Lynn Sudha M. Cowsik Sarata C. Sahu S. Chauhan A. Bhattacharya G. Govil Anil Kumar Maurizio Pellecchia Erik R. P. Zuiderweg Keiichi Kawano Tomoyasu Aizawa Naoki Fujitani Yoichi Hayakawa Atsushi Ohnishi Tadayasu Ohkubo Yasuhiro Kumaki Kunio Hikichi Katsutoshi Nitta V. Rani Parvathy R. M. Kini Takumi Koshiba Yoshihiro Kobashigawa Min Yao Makoto Demura Astushi Nakagawa Isao Tanaka Kunihiro Kuwajima Jens Linge Seán O. Donoghue Michael Nilges G. Chakshusmathi Girish S. Ratnaparkhi P. K. Madhu R. Varadarajan C. Tetreau Molecular Biophysics Unit Indian Institute of Science Bangalore India Austrian Academy of Sciences Institute of Biophysics and X-ray Structure Research Graz Austria Faculty of Biology University of Konstanz Germany Institute of Medical Biochemistry University of Graz Austria Howard Huges Medical Institute Department of Chemistry & Biochemistry University of California La Jolla USA Department of Chemistry & Biochemistry University of California San Diego La Jolla USA Molecular Biophysics Unit India Department of Microbiology &Cell Biology Indian Institute of Science Bangalore India Macromolecular Structure Laboratory NCI - Frederick Cancer Research and Development Center ABL - Basic Research Program Frederick USA Department of Crystallography and Biophysics University of Madras Chennai Biochemistry Department Indian Institute of Science Bangalore India Condensed Matter Physics Division B.A.R.C. Trombay Mumbai Condensed Matter Physics Division Bhabha Atomic Research Centre Trombay Mumbai IMCB The University of Tokyo Tokyo Japan Mitsubishi Chemical Corporation Yokohama Research Center Yokohama Japan Faculty of Pharmaceutical Sciences Chiba University Chiba Japan Department of Biophysics All India Institute of Medical Sciences New Delhi India Department of Biophysics All India Institute of Medical sciences New Delhi India Institüt Physiologische Chemie Hamburg Germany Biophysics Department Bose Institute Calcutta India Slovak Academy of Sciences Institute of Molecular Biology Bratislava Slovakia Indian Institute of Science Bioinformatics Centre Bangalore Departments of Chemistry and Biochemistry Biological Macromolecular Structure Center USA Bulgarian Academy of Sciences Institute of Organic Chemistry Sofia Bulgaria Chinese Academy of Sciences Institute of Biophysics Beijing China Novartis Pharma AG Preclinical Research Basel Switzerland Department of Chemical Sciences Tata Institute of Fundamental Research Mumbai India Solid State Physics Div

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Applying fuzzy functions and sequential coordination to optimization of machinery arrangement and pipe routing

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NAVAL ENGINEERS JOURNAL 1998年第6期110卷 43-54页

作者： Wu, BC Young, GS Schmidt, W Choppella, K Dr. Bi-Chu Wu:received a PhD in Mechanical Engineering from the University of Maryland College Park in 1991. She has worked on projects involving naval architecture design optimization solid mechanics and database development. Presently a senwr engineer with Angle Incorporated Dr Wu's research interests are in design optimization and fuzzy logic applications. Dr. Gin-Shu Young: a senior engineer with Angle Incorporated holds a PhD in Mechanical Engineering from the University of Maryland College Park. As a guest researcher with National Institute of Standards and Technologies from 1990 to 1993 he worked on vision-based navigation for autonomous vehicles. His experience also includes applications of optimization fuzzy logic neural network and genetic algorithm methods to engineering system design Mr. William Schmidt:co-founded Angle Incorporated in 1990 and has served as Vice PresidentlChiefScientist during this tame. He holds a B.Sc. in Applied Science from the Naval Acadt?my and an M.Sc. in Physics from the Naval Post Graduate School. He has cner 20 years experience in technical leadership material and personnel management. He has led the application of computer aided design (CAD) and Product Model Information Exchange to the shipbuilding industry. His experience also includes leading the amlication of model based operational analysis to support the Live Fire Test Program for DDG 51 Class Destroyers. Mr. Krishna M. Choppella:is a Sofware Engineer at Eidea Laboratories Incotporated where he works on componentbased distributed enterpvise frameworks. He has been involved in creating data analysis tools for the US Nay by integrating CAD modeis databases and graphical front ends. His work in the Masters degree program in Mechanical Engineering at the University of Texas at Austin was in di0ddase.r spectroscopy of combustion products in porous-matri burners. He received his Bachelors degree in Electrical Engineering in India. He was a Research Associate at the Centre for Laser Technology and Project Engi

Ship design is often multidisciplinary involving several design elements with various types of objectives and constraints (O/C) some easily described as mathematical formulas, others better modeled as descriptive assertions. This paper describes a method based on fuzzy functions and an integrated performance index to model O/C using descriptive assertions to be used with mathematical formulas in optimization. Another issue addressed in this paper concerns the coordination of design elements when sequentially coupled, that is, when one leads the other and the performance of the follower depends greatly on the design of the leader. Based on neuro-fuzzy techniques, the method described here coordinates and optimizes sequentially coupled elements. The two methods are applied to machinery arrangement (MA) and pipe routing (PR). Preliminary models for optimization of MA and PR are described considering convenience, producibility: engine room size, interference and location as factors in the O/C set. Some test results from MA/PR applications are presented and discussed. The methods are generic and can be extended to other elements in ship design. They are mutually independent and may be used separately Two advantages of their use are an improvement in overall performance and a reduction in the need for redesign of elements.

关键词： Optimization

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Numerical analysis of compressible fluids and elastic structures interactions

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Applied Mechanics Reviews 1995年第11/2期48卷 S195页

作者： Vaz, dos Santos, M.A. Awruch, A.M. Department of Materials Science and Building Fundac¸a˜o Universidade do Rio Grande Rua Eng Alfredo Huch 475 96201-900 Rio Grande RS Brazil Graduate Program in Civil and Mechanical Engineering Universidade Federal do Rio Grande do Sul Av Osvaldo Aranha 99 3° Andar 90035-190 Porto Alegre RS Brazil

A finite element algorithm to simulate two dimensional flows of viscous and inviscid compressible fluids for a wide range of Mach numbers is presented in this work. This model is coupled to immersed deformable structures through equilibrium and compatibility conditions in order to analyze its dynamic behavior. For the fluid, time integration is performed by a two-step Taylor-Galerkin explicit scheme and Newmark’s method is used to obtain the dynamic response of the structure. An arbitrary mixed Euler-Lagrange description is used to re-define a new finite element mesh in the presence of the immersed structure displacements. Finally, several examples are included showing the model behavior and possibilities for future expansions.

关键词： Dynamic response Mach number Fluids Flow (Dynamics) Equilibrium (Physics) Numerical analysis Algorithms Finite element analysis

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Evaluation of the Recreio Flowsheet — COPELMI

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Fuel 1993年第5期72卷 722-722页

作者： C.H. Sampaio L.A.C. Klujszo G.F. Cavalcante Post-Graduate Program on Metallurgical and Materials Engineering (PPGEMM) Federal University of Rio Grande do Sul (UFRGS) Porto Alegre Brazil

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