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141.
J. Charlier S. Ameur J.P. Bourgoin C. Bureau S. Palacin 《Advanced functional materials》2004,14(2):125-132
This work presents a new one‐step process enabling the mask‐free localized functionalization by organic polymers of the conducting or semiconducting parts of composite surfaces at the micrometer and submicrometer scale. The functionalization is carried out via cathodic electrografting of suitable precursors of composite cathodes, which gives an insulating polymer film strongly grafted to selected parts of the composite electrodes and guarantees that the resolution is that of the pre‐existing pattern, even when the whole surface is dipped into the reaction medium. The presumed mechanism is based on a regioselective extraction of electrons from the composite surface according to its apparent local work function in solution. 相似文献
142.
Xin Wang 《Engineering Fracture Mechanics》2003,70(6):731-756
Three-dimensional finite element analyses have been conducted to calculate the elastic T-stress for semi-elliptical surface cracks in finite thickness plates. Far-field tension and bending loads were considered. The analysis procedures and results were verified using both exact solutions and approximate solutions. The T-stress solutions are presented along the crack front for cracks with a/t values of 0.2, 0.4, 0.6 or 0.8 and a/c values of 0.2, 0.4, 0.6 or 1.0. Based on the present finite element calculations for T-stress, empirical equations for the T-stress at three locations: the deepest, the surface and the middle points of the crack front under tension or bending are presented. The numerical results are approximated by empirical formulae fitted with an accuracy of 1% or better. They are valid for 0.2?a/c?1 and 0?a/t?0.8. These T-stress results together with the corresponding K or J values for surface cracks are suitable for the analysis of constraint effects for surface cracked components. 相似文献
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146.
W. Ming F. Melis R. D. van de Grampel L. van Ravenstein M. Tian R. van der Linde 《Progress in Organic Coatings》2003,48(2-4):316-321
Self-stratification strategy can be used to prepare films in which both bulk and surface properties can be optimized. By using this approach, only a very small quantity of fluorinated species is needed to generate a surface with low surface energy. When cross-linking is involved during film formation, we are dealing with a competition behavior between the diffusion of fluorinated species and the formation of cross-linked network. In this study low surface energy polymeric films were prepared on the basis of partially fluorinated polyisocyanates, in combination with hydroxyl-end-capped three-armed solventless liquid oligoesters and modified hyperbranched polyesters. At a fluorine concentration of only 0.5 wt.%, contact angles of water and hexadecane can reach 120° and 80°, respectively. A surface energy as low as 10–15 mN/m can be obtained upon the addition of less than 1 wt.% of fluorine in the films. It was shown, from real time ATR-FTIR and contact angle measurements, that the curing temperatures demonstrated significant effects on the cross-linking rate as well as on the wettability of the films. 相似文献
147.
W. S. Gutowski Sheng Li Con Filippou Pamela Hoobin Steven Petinakis 《The Journal of Adhesion》2003,79(5):483-519
Part I of this paper reviewed the theoretical principles of the macromolecular design of polymer interface/interphase systems for obtaining maximum adhesion and fracture performance of adhesively bonded assemblies. In Part II a novel, relatively simple and industry-feasible technology for surface-grafting connector molecules is demonstrated and discussed in detail and supported by a range of experimental examples. It is shown, in agreement with contemporary theory, that the use of chemically attached graft chemicals of controlled spatial geometry and chemical functionality enables a significant increase in the strength and fracture energy of the interphase, to the point of cohesive fracture of the substrate, or that of an adjacent medium such as adhesive, elastomer, or other material. This occurs even after prolonged exposure of investigated systems to adverse environments such as hot water. 相似文献
148.
本文在理论和试验两个方面探讨了离子注入中的热效应和温升现象。注入样品的温升对离子注入层的性能有直接影响。分析了理论计算注入样品温升的一些情况。给出了实际测量注入样品温升的几种试验方法。阐明了控制注入样品温升的若干可能途径。 相似文献
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150.
Experimental investigation of natural convection from a horizontal ice surface melting in pure water
Byung-Ha Kim Seung-Hwan Cho Kap-Jong Riu 《Journal of Mechanical Science and Technology》1991,5(2):93-103
A study on natural convection from a horizontal ice surface melting in pure water was conducted experimentally for the ambient
water temperature from 2▿C to 10°C. Natural convection flow around upward-or downward-facing horizontal ice plate was divided
into three regions according to the temperature variation of ambient water. The flow patterns of three regions were no flow,
two-dimensional steady laminar flow and unsteady flow. Mean Nusselt number for the upward-facing surface had its maximum value
at about 3°C of ambient water temperature. However, in the case of the downward-facing surface it increased as the ambient
water temperature increased. 相似文献