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71.
Fabian Buffa Gustavo A. Abraham Brian P. Grady Daniel Resasco 《Journal of Polymer Science.Polymer Physics》2007,45(4):490-501
A commercially available aliphatic thermoplastic polyurethane formulated with a methylene bis(cyclohexyl) diisocyanate hard segment and a poly(tetramethylene oxide) soft segment and chain‐extended with 1,4‐butanediol was dissolved in dimethylformamide and mixed with dispersed single‐walled carbon nanotubes. The properties of composites made with unfunctionalized nanotubes were compared with the properties of composites made with nanotubes functionalized to contain hydroxyl groups. Functionalization almost eliminated the conductivity of the tubes according to the conductivity of the composites above the percolation threshold. In most cases, functionalized and unfunctionalized tubes yielded composites with statistically identical mechanical properties. However, composites made with functionalized tubes did have a slightly higher modulus in the rubbery plateau region at higher nanotube fractions. Small‐angle X‐ray scattering patterns indicated that the dispersion reached a plateau in the unfunctionalized composites that was consistent with the plateau in the rubbery plateau region. The room‐temperature modulus and tensile strength increase was proportionally higher than almost all increases seen previously in thermoplastic polyurethanes; however, the increase was still an order of magnitude below what has been reported for the best nanotube–polymer systems. Nanotube addition increased the hard‐segment glass transition temperature slightly, whereas the soft‐segment glass transition was so diffuse that no conclusions could be drawn. Unfunctionalized tubes suppressed the crystallization of the hard segment; whereas functionalized tubes had no effect. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 490–501, 2007 相似文献
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The Canadian Light Source (CLS) is constructing two beamlines for Infrared Spectroscopy using synchrotron radiation (IRSR). One will supply mid-Infrared (2–25 μ) light to a Fourier Transform Infrared (FTIR) spectrometer and microscope for biological applications. The second will have a high resolution FTIR spectrometer for gas-phase and surface spectroscopy in the far-Infrared (beyond 25 μ). The Infrared beamlines will use dipole bending magnet radiation from a special bend magnet port design which provides a 50 mrad square acceptance. Issues with the first mirror and photon mask design, as well as the beamline layout and features are discussed. 相似文献
74.
文献[1]引入一类具有广泛应用前景的随机过程-Markov骨架过程。借助Markov骨架过程的方法研究GI/G/1单重休假服务系统队长,及t时刻到达顾客等待时间的瞬时概率分布。 相似文献
75.
M.A. Grado-Caffaro 《Optik》2003,114(5):237-238
Sensitivity of the velocity of a single electron, in the relativistic case, to a perpendicular magnetic field is evaluated by defining a parameter which becomes useful in a number of cases related to dynamical systems. In particular, the ultrarelativistic case is examined. 相似文献
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The dynamics of a single electron submitted to a linearly polarized laser field is examined in the non-relativistic case by calculating an upper bound of the position of the electron in the time domain. 相似文献
78.
关于杨氏干涉条纹的讨论 总被引:1,自引:0,他引:1
阐述了杨氏干涉实验中,理论上应该看到明暗相间双曲线条纹,而实际上,在实验室中看到的是明暗相间直线条纹。 相似文献
79.
潜热型热功能流体强化换热分析 总被引:4,自引:0,他引:4
本文建立了分析带有相变微胶囊的潜热型热功能流体的流动和换热过程数理模型,应用有限差分法和移动热源法进行联合求解。计算结果表明,相变微胶囊的加入:较好地提高了流体的换热性能。获得了相变颗粒大小和体积分数对强化换热影响等结果。计算结果对该类流体的设计和应用提供了理论依据。 相似文献
80.