共查询到20条相似文献,搜索用时 15 毫秒
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《Current Opinion in Solid State & Materials Science》2001,5(5):445-450
The modeling of polymers, the most prominent of soft materials, has reached a level of maturity within the last few years, but new advances are being made in several areas of considerable practical importance. New sampling techniques are being developed to accelerate the exploration of configuration space, which has been and continues to be of paramount importance in the determination of the properties of polymeric materials. Simultaneous length and time scale problems are being addressed with new coarse-grained methods, while more traditional methods are being applied to problems of increasing chemical complexity and reality. These several advances are yielding unprecedented insights into the relative importance of intramolecular (manifested in long-range polymeric structure) and intermolecular interactions in determining the properties of materials. 相似文献
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Ihsan Amin Marin Steenackers Ning Zhang André Beyer Xianghui Zhang Tobias Pirzer Thorsten Hugel Rainer Jordan Armin Gölzhäuser 《Small (Weinheim an der Bergstrasse, Germany)》2010,6(15):1623-1630
The fabrication of defined polymer objects of reduced dimensions such as polymer‐coated nanoparticles (zero‐dimensional (0D)), cylindrical brushes (1D), and polymer membranes (2D), is currently the subject of intense research. In particular, ultrathin polymer membranes with high aspect ratios are being discussed as novel materials for miniaturized sensors because they would provide extraordinary sensitivity and dynamic range when sufficient mechanical stability can be combined with flexibility and chemical functionality. Unlike current approaches that rely on crosslinking of polymer layers for stabilization, this report presents the preparation of a new class of polymer material, so‐called “polymer carpets,” a freestanding polymer brush grown by surface‐initiated polymerization on a crosslinked 1‐nm‐thick monolayer. The solid‐supported, as well as freestanding, polymer carpets are found to be mechanically robust and to react instantaneously and reversibly to external stimuli by buckling. The carpet mechanics and the dramatic changes of the film properties (optical, wetting) upon chemical stimuli are investigated in detail as they allow the development of completely new integrated micro‐/nanotechnology devices. 相似文献
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Christopher Emslie 《Journal of Materials Science》1988,23(7):2281-2293
The background to the development of polymer optical fibres (POFs) and the methods used for their manufacture are described. The optical properties of polymers are then discussed in the context of fibres, taking the most common POF materials, polymethylmethacrylate and polystyrene, as examples. The poor market penetration of POFs, due to inadequate performance in terms of attenuation, bandwidth and temperature resistance, is then explained. The article concludes with a discussion of techniques which show great promise for the development of a new generation of high-performance POFs which will satisfy market demands.Nomenclature
n
1,n
2
Refractive indices of core and cladding
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A
Acceptance angle
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Turbidity
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(LSO)
Isotropic turbidity
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Wavelength
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Density
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Dielectric constant
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T
Temperature
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T
f
Fictive temperature
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T
g
Glass transition temperature
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k
Boltzmann constant
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T
Isothermal compressibility
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C
u
Cabannes factor
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u
Depolarization factor
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e
Ultraviolet absorption loss (dB km–1)
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Frequency
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K
Interatomic force constant
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Reduced mass
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m
1,m
2
Mass
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t
s
Delay time
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c
Velocity of light
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1
Bit-rate 相似文献
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V. N. Pokrovskii 《Journal of Engineering Physics and Thermophysics》1966,10(3):199-200
Isothermal steady flow of an incompressible medium consisting of long elastic molecules is examined.This work was begun in the All-Union Synthetic Fiber Scientific Research Institute, Kalinin. 相似文献
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Polymer nanocomposite foams 总被引:7,自引:0,他引:7
L. James Lee Changchun Zeng Xia Cao Xiangming Han Jiong Shen Guojun Xu 《Composites Science and Technology》2005,65(15-16):2344
Polymer nanocomposite foams have received increasingly attention in both scientific and industrial communities. The combination of functional nanoparticles and supercritical fluid foaming technology has a high potential to generate a new class of materials that are lightweight, high strength and multifunctional. A small amount of well-dispersed nanoparticles in the polymer domain may serve as the nucleation sites to facilitate the bubble nucleation process. Moreover, the nano-scaled particles are suitable for micro-scaled reinforcement, thus achieving the macroscopic mechanical enhancement. In this paper, we will first briefly review the synthesis and processing techniques of nanocomposites based on polymers that are important in the foam industry. Both thermoplastic and thermoset nanocomposite foams will be addressed. This is followed by an introduction of various foaming techniques. The effect of nanoparticles on the foam morphology and properties is then discussed. We conclude with the current and future trends of nanocomposite foams in both industrial and biomedical applications. 相似文献
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Methyl methacrylate styrene and acrylonitrile homopolymer as well as copolymer impregnated concrete specimens were subjected to accelerated durability tests in aqueous sulphuric acid, hydrochloric acid, ammonium chloride, sodium chloride, sodium hydroxide, sea water and crude oil media. The effects of such corrosive stagnant environments on compressive strength, flexural strength, strength of transverse rupture and modulus of elasticity have been studied. A durability mechanism has been proposed to account for the observed behaviour of polymer impregnated concrete. 相似文献
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Mrs. C. Perényi 《Materials and Structures》1968,1(1):13-21
Summary Aqueous polymer dispersions admixed to cement concretes or mortars affect their properties. Some research work has been made
to find the optimum type and proportion of polymer dispersion admixture, and to see how concrete and mortar properties are
thereby modified.
Résumé Les émulsions de polymères dans l’eau modifient les propriétés des mortiers et bétons de ciment. On expose ici quelques recherches faites afin de déterminer la proportion optimale et le type de polymère à employer dans ces émulsions, et l’on montre comment les propriétés du mortier et du béton en sont modifiées.相似文献