检索结果-内蒙古大学图书馆

Site-specific forest-assembly of single-wall carbon nanotubes on electron-beam patterned SiOx/Si substrates

Materials science and engineering C 2008年第8期28卷 1366-1371页

作者： Wei, Haoyan Kim, Sang Nyon Kim, Sejong Huey, Bryan D. Papadimitrakopoulos, Fotios Marcus, Harris L. Materials Science and Engineering Program Department of Chemical Materials and Biomolecular Engineering Institute of Materials Science Storrs CT 06269 United States Nanomaterials Optoelectronics Laboratory Polymer Program Institute of Materials Science Storrs CT 06269 United States

Based on electron-beam direct writing on the SiOx/Si substrates, favorable absorption sites for ferric cations (Fe3+ ions) were created on the surface oxide layer. This allowed Fe3+-assisted self-assembled arrays of single-wall carbon nanotube (SWNT) probes to be produced. Auger investigation indicated that the incident energetic electrons depleted oxygen, creating more dangling bonds around Si atoms at the surface of the SiOx layer. This resulted in a distinct difference in the friction forces from unexposed regions as measured by lateral force microscopy (LFM). Atomic force microscopy (AFM) affirmed that the irradiated domains absorbed considerably more Fe3+ ions upon immersion into pH 2.2 aqueous FeCl3 solution. This rendered a greater yield of FeO(OH)/FeOCl precipitates, primarily FeO(OH), upon subsequent washing with lightly basic dimethylformamide (DMF) solution. Such selective metal-functionalization established the basis for the subsequent patterned forest-assembly of SWNTs as demonstrated by resonance Raman spectroscopy. © 2008 Elsevier B.V. All rights reserved.

关键词： Chlorine compounds

来源：评论

学校读者我要写书评

暂无评论

Chemiresistive NO gas sensor based on zinc oxide nanorods

引用

Journal of Bionanoscience 2008年第2期2卷 102-108页

作者： Lin, Chia-Yu Nien, Po-Chin Feng, Wei-Yi Lin, Chii-Wann Tunney, Jim Ho, Kuo-Chuan Department of Chemical Engineering National Taiwan University Taipei 10617 Taiwan Institute of Biomedical Engineering National Taiwan University Taipei 10617 Taiwan Institute of Electrical Engineering National Taiwan University Taipei 10617 Taiwan Institute for Chemical Process and Environmental Technology National Research Council of Canada Ottawa ON K1A 0R6 Canada Institute of Polymer Science and Engineering National Taiwan University Taipei 10617 Taiwan

The synthesis of zinc oxide (ZnO) nanorods and their sensing properties with respect to nitric oxide (NO) gas were studied. The ZnO nanorods were grown by the hydrothermal method onto a ZnO thin film (∼ 150 nm), which was designated as the ZnO thin film/ZnO nanorods. The ZnO thin film was pre-sputtered on the Au interdigitated electrode. By repeating the growth in a fresh precursor from one cycle to four cycles, the aspect ratio of the nanorods increased approximately from 10 to 33. For NO gas sensor application, however, the sensitivity decreased as the aspect ratio of the ZnO nanorods increased. It's very likely that higher density and higher aspect ratio of ZnO nanorods prevent NO gas from penetrating into the ZnO nanorods. The optimal operation temperature for the ZnO thin film/ZnO nanorods with an aspect ratio of 10 was found to be 240 °C for sensing NO gas. The limit of detection reached 2 ppb which is applicable for asthma diagnosis. To simulate human breath, cross-sensitivities with respect to CO2 and O2 have been tested. Copyright © 2008 American Scientific Publishers All rights reserved.

关键词： Nitric oxide

来源：评论

学校读者我要写书评

暂无评论

Hydroxyapatite- polylactide composite for bone repair

Hydroxyapatite- polylactide composite for bone repair

引用

66th Annual Technical Conference of the Society of Plastics Engineers, Plastics Encounter at ANTEC 2008

作者： Sun, Shih-Po Shaw, Montgomery T. Wei, Mei Olson, James Polymer Program Institute of Materials Science University of Connecticut Storrs CT United States Department of Chemical Materials and Biomolecular Engineering University of Connecticut Storrs CT United States Teleflex Medical Inc.

ISBN: (纸本)9781605603209

The aim of this study was to investigate the interealtions between the design, processing and properties of hydroxyapatite-poly(lactide) composites intended as biodegradable bone grafts for joining fractured bone tissues. Poly(lactide) fibers were employed to increase the axial strength and toughess of the composite. The hydroxyapatite nano rods are also aligned in the axial direction during the pultrusion process to increase the low-strain modulus of the composite. The resulting composite with a composition of HA: PCL: PLA= 3: 34: 63 (vol%) had a tensile modulus of 6.6 GPa.

关键词： Hydroxyapatite

来源：评论

学校读者我要写书评

暂无评论

Thermal Stability Study of Cu(MoN x ) Seed Layer on Barrierless Si

引用

Journal of Electronic Materials 2008年第1期38卷 100-107页

作者： J.P. Chu C.H. Lin W.K. Leau V.S. John Department of Polymer Engineering National Taiwan University of Science and Technology Taipei Taiwan Department of Environmental Engineering Chin-Min Institute of Technology Tou-Fen Taiwan Institute of Materials Engineering National Taiwan Ocean University Keelung Taiwan Department of Physics T.D.M.N.S. College T. Kallikulam India

This study reports the good thermal stability of a sputtered Cu(MoN x ) seed layer on a barrierless Si substrate. A Cu film with a small amount of MoN x ...

This study reports the good thermal stability of a sputtered Cu(MoN x ) seed layer on a barrierless Si substrate. A Cu film with a small amount of MoN x was deposited by reactive co-sputtering of Cu and Mo in an Ar/N2 gas mixture. After annealing at 560°C for 1 h, no copper silicide formation was observed at the interface of Cu and Si. Leakage current and resistivity evaluations reveal the good thermal reliability of Cu with a dilute amount of MoN x at temperatures up to 560°C, suggesting its potential application in advanced barrierless metallization. The thermal performance of Cu(MoN x ) as a seed layer was evaluated when pure Cu is deposited on top. X-ray diffraction, focused ion beam microscopy, and transmission electron microscopy results confirm the presence of an ∼10-nm-thick reaction layer formed at the seed layer/Si interface after annealing at 630°C for 1 h. Although the exact composition and structure of this reaction layer could not be unambiguously identified due to trace amounts of Mo and N, this reaction layer protects Cu from a detrimental reaction with Si. The Cu(MoN x ) seed layer is thus considered to act as a diffusion buffer with stability up to 630°C for the barrierless Si scheme. An electrical resistivity of 2.5 μΩ cm was obtained for the Cu/Cu(MoN x ) scheme after annealing at 630°C.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Monitoring of the Sol-Gel Synthesis of Organic-inorganic Hybrids by FTIR Transmission, FTIR/ATR, NIR and Raman Spectroscopy

引用

Macromolecular Symposia 2008年第1期265卷

作者： D. Fischer D. Pospiech U. Scheler R. Navarro M. Messori P. Fabbri Leibniz Institute of Polymer Research Dresden Hohe Str. 6 01069 Dresden Germany Institute of Polymer Science and Technology CSIC Juan de la Cierva 3 28006 Madrid Spain University of Modena and Reggio Emilia Department of Materials and Environmental Engineering Via Vignolese 905/A 41100 Modena Italy

Summary: The sol-gel synthesis of organic-inorganic hybrids based on triethoxysilane- terminated poly(ethylene oxide) and tetraethylorthosilicate was monitored in-situ using three spectroscopic methods (FTIR/ATR, Raman, NIR). These spectroscopic methods allow in-situ monitoring of the evolution of hybrid materials starting from the modification of the polymer and the early steps of hydrolysis up to the network formation. By application of 29 Si solid-state NMR spectroscopy the assignment and quantification of the Raman bands to different end groups and different cross-linking states was made. The sol-gel reaction was also followed by in-line NIR spectroscopy. A multivariate data analysis was accomplished to obtain a conversion-time curve. Furthermore, we investigated spin-coated films on wafers using FTIR transmission spectroscopy.

关键词： in-line spectroscopy In-situ monitoring organic-inorganic hybrids poly(ethylene oxide) sol-gel

来源：评论

学校读者我要写书评

暂无评论

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

引用

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

来源：评论

学校读者我要写书评

暂无评论

Synchrotron X-ray scattering studies of star-shape polymers

Synchrotron X-ray scattering studies of star-shape polymers

引用

2007 NSTI Nanotechnology Conference and Trade Show - NSTI Nanotech 2007

作者： Jin, S. Higashihara, T. Jin, K.S. Yoon, J. Heo, K. Kim, J. Kim, K.-W. Hirao, A. Ree, M. BK21 Program Polymer Research Institute Pohang University of Science and Technology Pohang 790-784 Korea Republic of Polymeric and Organic Materials Department Graduate School of Science and Engineering Tokyo Institute of Technology Tokyo 152-8552 Japan

Shapes and structures of star-polystyrenes bearing 6 to 57-arms were in detail investigated in good and theta solvents by small-angle X-ray scattering with synchrotron radiation sources.

ISBN: (纸本)1420063766

Shapes and structures of star-polystyrenes bearing 6 to 57-arms were in detail investigated in good and theta solvents by small-angle X-ray scattering with synchrotron radiation sources.

关键词： Polystyrenes

来源：评论

学校读者我要写书评

暂无评论

Inside Front Cover: Field‐Driven Biofunctionalization of polymer Fiber Surfaces during Electrospinning (Adv. Mater. 1/2007)

引用

Advanced Materials 2007年第1期19卷

作者： X.‐Y. Sun R. Shankar H. G. Börner T. K. Ghosh R. J. Spontak Department of Chemical & Biomolecular Engineering North Carolina State University Raleigh NC 27695 USA Department of Materials Science & Engineering North Carolina State University Raleigh NC 27695 USA Fiber & Polymer Science Program North Carolina State University Raleigh NC 27695 USA Department of Colloid Chemistry Max‐Planck Institute of Colloids & Interfaces 14424 Potsdam Germany

Surface‐biofunctionalized synthetic polymer fibers composed of a fiber‐forming host polymer and an oligopeptide conjugate can be prepared from electrospinning, report Spontak and co‐workers on p. 87. The conjugate consists of a polypeptide segment and a polymer block that is compatible with the host polymer. Because the more polarizable peptide segment migrates to the surface during electrospinning, peptide surface‐enrichment is achieved in a single step without further treatment.

关键词： Biocompatible materials Block copolymers Electrospinning Fibers Peptides Poly(ethylene oxide) Surface functionalization

来源：评论

学校读者我要写书评

暂无评论

DNA-assisted binding of microspheres on glass substrates and their laser-induced release

引用

Materials science and engineering C 2006年第8期26卷 1401-1407页

作者： Kim, Sejong Geiss, Erik Yu, Phillip Papadimitrakopoulos, Fotios Marcus, Harris L. Nanomaterials Optoelectronics Laboratory Department of Chemistry Polymer Program Storrs CT 06269-3136 United States Department of Materials Science and Engineering Institute of Materials Science University of Connecticut Storrs CT 06269-3136 United States

DNA hybridization has been increasingly adopted in materials sciences due to its complementary nature of single stranded DNAs. This unique property could be potentially used in the realization of 2 dimensional (2D) arrays of colloidal microspheres as a precursor to further build more complicated superstructures. In order to precisely understand this DNA-assisted assembly of colloidal particles, we quantitatively assessed the surface density of grafted and hybridizing accessible DNA oligomers on both substrate and colloidal particles. The DNA grafting densities were determined by UV-Vis of dye-functionalized complementary DNA oligomers, in conjunction with theoretical models. The variations of the concentration of hybridized DNA as a function of parameters such as the number of DNA base pairs (bp), the length of spacer and the size of sphere were also investigated to determine the immobilization strength of colloidal microspheres on the substrate. Dehybridization of the particle was conducted by utilizing a focused laser beam. These results were also compared with the particle hybridization energies and modeled according to the sum of DNA bindings as a function of the number of hybridized bases. © 2005.

关键词： Glass

来源：评论

学校读者我要写书评

暂无评论

Small-angle x-ray scattering from cylindrically self-assembled molecules

Small-angle x-ray scattering from cylindrically self-assembl...

引用

55th Society of polymer science Japan Symposium on Macromolecules

作者： Kudo, Yasuya Sakurai, Kazuo Jeong, Yeonhwan Ishi-I, Tsutomu Graduate School of Environmental Engineering University of Kitakyushu Fukuoka 808-0135 Japan Department of Polymer Science and Engineering Kyoto Institute of Technology Kyoto 606-8585 Japan Institute for Materials Chemistry and Engineering Kasuga-koen Kasuga 816-8508 Japan

A disk-like triazine compound, denoted by TRI-C8 can self-assemble in octane or cyclohexane, and the solution becomes highly viscoelastic. Spectroscopy and microscopy revealed that TRI-C8 can stack with each other with the π-π and hydrogen-bond interactions. In this report, we investigate the nano-structure of the TRI-C8 aggregate by use of scattering technique.

关键词： Molecular structure

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：