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Transactions - 7th World Biomaterials Congress

作者： Nakamae, M. Takahashi, T. Ishii, T. Nagasaki, Y. Kataoka, K. Preventure Program JST Department of Materials Science Tokyo University of Science Yamazaki2641 Noda 278-8510 Japan Department of Matereals Science Graduate School of Engineering University of Tokyo Hongo 7-3-1 Bunkyo-ku Tokyo 113-8656 Japan

ISBN: (纸本)1877040193

The stable dispersion of quantum dot nanoparticles (QD) in aqueous solution using polymers containing poly(ethylene glycol) (PEG) segment was investigated. It was found that using PEG/poly(2-N,N-dimethylaminoethyl methacrylate) (PEG-b-PAMA) enables stabilization of QD in aqueous phase. The photochemical characteristics of the PEG-modified QD were found to be almost same as unmodified QD. It was observed that as he PEG/PAMA block copolymer-modified QDs possess PEG tethered chains on the surface, it is highly dispersion stable in aqueous media and also showed non-fouling character.

关键词： Semiconductor quantum dots

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Extruded LZS glass-ceramics

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American Ceramic Society Bulletin 2004年第8期83卷

作者： Montedo, O.R.K. Reitz, G.M. Bertan, F.M. De Novaes Oliveira, A.P. Hotza, D. Siligardi, C. Graduate Program in Materials Science and Engineering Federal University of Santa Catarina Florianópolis Brazil Dept. of Materials and Environment Engineering University of Modena and Reggio Emilia Modena Italy

Experimental results regarding Li2O-ZrO2-SiO 2 (LZS) sintered glass ceramic materials obtained by extrusion of glass powders with an added inorganic material as binder, are presented. Each of the composition were characterized by chemical analysis, laser scattering particle-size analysis, differential thermal analysis (DTA), Xray diffractometry (XRD), and thermal expansion. It was observed that after a sintering process at near by 750°C, crystallization takes place as soon as the process gets over. Once heated, the the glass powder compacts crystallize into zircon and quartz and then to lithium disilicate.

关键词： Glass ceramics

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Molecular recognition by stable dispersion of gold nanoparticles modified with heterobifunctional poly (ethylene glycol)

Molecular recognition by stable dispersion of gold nanoparti...

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Transactions - 7th World Biomaterials Congress

作者： Aboshi, F. Takahashi, T. Ishii, T. Nagasaki, Y. Otsuka, Hidenori Kataoka, K. Pre-venture Program JST 4-1-8 Hon-machi Kawaguchi Saitama 332-0012 Japan Department of Materials Science Tokyo University of Science 2641 Yamazaki Noda Chiba 278-8510 Japan Department of Matereals Science Graduate School of Engineering University of Tokyo 7-3-1 Hongo Bunkyo-ku Tokyo 113-8656 Japan

ISBN: (纸本)1877040193

The stability of gold nanoparticles modified with heterobifunctional poly (ethylene glycol) (PEG) were investigated. An effective method for preparing hetero-bifunctional PEG by anionic ring-opening polymerization was also developed. Streptavidin-PEG gold nanoparticle showed extremely high response with biotinylated surface plasmon resonance (SPR) sensors. PEG-modified gold nanoparticles showed remarkable stability in physiological conditions, such as the solution of high ionic strength.

关键词： Nanostructured materials

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PH dependence of polypseudorotaxane formation between cationic linear polyethylenimine and cyclodextrins

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Macromolecules 2004年第18期37卷 6705-6710页

作者： Choi, Hak Soo Ooya, Tooru Lee, Sang Cheon Sasaki, Shintaro Kurisawa, Motoichi Uyama, Hiroshi Yui, Nobuhiko School of Materials Science Japan Adv. Inst. Sci. and Technol. 1-1 Asahidai Tatsunokuchi Ishikawa 923-1292 Japan Inst. of Bioeng. and Nanotechnology Singapore Science Park II #01-01/10 The Aries 117586 Singapore Department of Materials Chemistry Graduate School of Engineering Osaka University Suita Osaka 565-0871 Japan 21st Century COE Program Japan Adv. Inst. Sci. and Technol. 1-1 Asahidai Tatsunokuchi Ishikawa 923-1292 Japan

A series of linear polyethylenimines (LPEIs) with various molecular weights were synthesized and used for pH-dependent polypseudorotaxane formation with α- or γ-cyclodextrins (α-, γ-CDs). The polypseudorotaxane formation was significantly dependent on the pH of the aqueous media. The maximum yield of the recovered polypseudorotaxane precipitates was observed at pH 11.0, whereas no complexation was observed in the pH range below 8.0 due to the protonation of secondary amine groups in LPEI backbones. This suggests that the ionization of the secondary amine groups leads to dethreading of CD molecules because PEI chains with cationic nature disfavor the hydrophobic cavities of CDs. The solid-state 13C CP/MAS NMR and X-ray diffraction measurements verified the successful formation of crystalline polypseudorotaxanes through the inclusion complexation. In addition, 1H NMR analysis showed that LPEI formed a 2:1 inclusion complex with α-CD ([EI]:[α-CD] = 2:1) and a 4:1 complex with γ-CD ([EI]:[γ-CD] = 4:1) as reported in the poly(ethylene glycol)-based polypseudorotaxane system. Such unique pH-controllable polypseudorotaxane formation may be useful in designing many building blocks for stimuli-responsive polyrotaxanes.

关键词： Polyethylenes

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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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Advances in aircraft carrier life cycle cost analysis for acquisition and ownership decision-making

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NAVAL ENGINEERS JOURNAL 2000年第3期112卷 97-110页

作者： Chewning, IM Moretto, SJ Irvin M. Chewning:is currently the Director of the Aircraft Carrier Cost Estimating and Industrial Analysis Group of the Naval Sea Systems Command. Over the past four years Mr. Chewning has guided the cost analysis effort for the new CVNX class aircraft carrier through a three-part analysis of alternatives and is currently steering it towards Milestone I in June of 2000. In 1999 the CVNX cost analysis team was presented the NAVSEA Association of Scientists and Engineers “outstanding team achievement” award for its work on the CVNX analysis of alternatives. Mr. Chewning's professional career includes over 16 years as an employee of Newport News Shipbuilding as a Pipe Fitter Piping Systems Designer Piping Systems Engineer and Cost Engineer. He has worked at the Naval Sea Systems Command since 1980 as a Senior Cost Analyst Branch Head and Deputy Division Director of the Cost Estimating and Analysis Division. He has preformed cost analysis work for virtually all USN combatant programs including submarines cruisers destroyers frigates and aircraft carriers. He also performed the cost analysis work for the OSD evaluation of the Israeli Naval Modernization Program in the 1980's. Mr. Chewning is also Chairman of the NATO Specialist Team on Ship Costing a subgroup of the NATO Naval Group Six on Ship Design. Under his leadership two Allied Naval Engineering Publications have been completed in the 1990's: ANEP-41 on Ship Costing and ANEP-49 on Ways to Reduce Costs of Ships. In 1999 the NATO Specialist Team on Ship Costing completed a paper titled “Manpower Reduction and the Use of Commercial Standards and Practices to Reduce Costs of Ships.” The result of this work will be incorporated in a future revision of the aforementioned ANEFs. Mr. Chewning is a graduate of North Carolina State University with a Bachelor of Science in Mechanical Engineering. Mr. Chewning has also completed courses at the University of Virginia and Christopher Newport University Mr. Chewning is a graduate of the Program Management College

The U.S. Navy recently conducted an analysis of alternatives (AOA) to set the stage for determining the characteristics and acquisition strategy for its next generation aircraft carrier. The platform design selected is expected to be in service throughout the 21st century. The parameters under consideration for change in the new carrier design lie in the areas of propulsion and electric power generation, aviation, survivability, service life, and total ownership cost (TOC) reduction. The issue of affordability is paramount This paper focuses on the need for the program management office and its supporting cost analysis staff to understand the life cycle cost (LCC) of the existing and proposed future aircraft carriers and to then translate these LCC's into meaningful information for cost-conscious decision making. The challenge is to relate the LCC in terms the key decision-makers and the engineering team can use to satisfy their respective roles. Thus, it is necessary to translate the results of the given ship design alternative LCC's into the paradigms of the respective stakeholders: Fleet User (operators of aircraft carriers) Ship Designers (translators of the fleet operator requirements) program Sponsors (providers of the funding resources) program Management Office, Ship builder and Supporting Industry (executors of the acquisition and construction of the ship) Navy and OSD decision-makers (overseers of program execution) The paper describes the aircraft carrier LCC breakdown structure that has resulted, in part, from a recent navy/shipbuilder integrated product team effort to capture total ownership costs. The structure has been used in the AOA as a tool to identify cost drivers and to add the time element to the cast equation in order to perform return on investment and program affordability analysis. The expanded ship work breakdown structure (ESWBS) has emerged as the central backbone of the cost work breakdown for AOA work. The ESWBS structure is a natural

关键词： Aircraft carriers

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