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1.
Lotus leaf-like polyurethane/Pluronic® F-127 surface was fabricated via replica molding using a natural lotus leaf as the template. Water contact angle measurements showed that both the hydrophobicity of the unmodified polyurethane (PU) surface and the hydrophilicity of the PU/Pluronic® surface were enhanced by the construction of lotus leaf-like topography. Protein adsorption on the PU/Pluronic® surface without topographic modification was significantly lower than on the PU surface. Adsorption was further reduced when lotus leaf-like topography was constructed on the PU/Pluronic® surface. Cell culture experiments with L929 cells showed that adhesion on the PU/Pluronic® surface with lotus leaf-like topography was low and adherent cells were spherical and of low viability. The PU/Pluronic® surface with lotus leaf-like topography thus appears to be resistant to nonspecific protein adsorption and to cell adhesion, and these effects derive from the both chemical composition and topography. The results suggest a new strategy based on surface topography for the design of antifouling materials.  相似文献   
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By potentiodynamic polarization of mechanically polished tantalum in a diluted aqueous solution of hexachloroplatinic acid, droplet-like platinum microparticles were electrodeposited, embedded into the simultaneously formed Ta2O5 film. The roughness factor of platinum of 31 was achieved. Within the potential region of both hydrogen and oxygen underpotential deposition, in both acidic and alkaline solutions, the composite Pt/Ta2O5 electrode displayed an excellent electrochemical response characteristic of smooth polycrystalline platinum. The preparation method applied in this work presents an easy way to obtain an electrode surface combining the behaviour of smooth polycrystalline platinum with the behaviour of microdisc arrays. Its electrocatalytic effectiveness was demonstrated for an oxygen reduction reaction in alkaline solutions.  相似文献   
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In the article, by employing multiple-scale, perturbation method, a new model is derived to describe the algebraic Rossby solitary waves generated by periodic external source in stratified fluid. The local conservation laws and analytic solutions of the model are obtained, and the breakup properties are discussed. By numeric simulation, some problems on the generation and evolution of the algebraic solitary waves under the influence of periodic external source are theoretically investigated. The results show that besides the solitary waves, an additional harmonic wave appears in the region of the external source forcing. Furthermore, the periodic variation of the external source forcing can prevent solitary waves from breaking. Meanwhile, the detuning parameter has an important effect on the breakup of the algebraic Rossby solitary waves.  相似文献   
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通过X射线光电子能谱(XPS)、椭圆偏振原位测试考察了氯化2,3,5-三苯基-2H-四唑(TTC), 2,4,6-三(2-吡啶基)-s-三嗪(TPT)分子在1 mol/L HCl中对碳钢表面的缓蚀作用, 并从微观上对二者的缓蚀机理进行探讨. XPS测试结果显示, 由C, N元素的1s特征峰产生的化学位移及其积分峰面积表明TTC, TPT分子在金属表面产生了有效抑制腐蚀的保护层; 由椭圆偏振原位测试并结合动电位极化曲线测试,考察了TTC, TPT分子对金属表面腐蚀反应的抑制程度, 并得到了相位差等参量, 结果表明二者在金属表面形成了具有缓蚀作用的覆盖层.  相似文献   
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Bellman-Gronwall积分不等式的一种推广   总被引:1,自引:1,他引:0  
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In this paper the authors study the oscillation and the asymptotic behavior of solutiosn to the second-order nonlinear differential equations $[\ddot x]\pmX(t,x,[\dot x])=0$(X_{\pm}) and give necessary and sufficient conditions for Equation (X_+) to have a bounded nonoscillatory solution or to be oscillatory. There are four classes of solutions to Equation (X_) with different asymptotic behavior. For each class of solution, the necessary or sufficient condition of the existence is obtained.  相似文献   
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The dissipative nonlinear Schrödinger equation with a forcing item is derived by using of multiple scales analysis and perturbation method as a mathematical model of describing envelope solitary Rossby waves with dissipation effect and external forcing in rotational stratified fluids. By analyzing the evolution of amplitude of envelope solitary Rossby waves, it is found that the shear of basic flow, Brunt-Vaisala frequency and β effect are important factors in forming the envelope solitary Rossby waves. By employing Jacobi elliptic function expansion method and Hirota's direct method, the analytic solutions of dissipative nonlinear Schrödinger equation and forced nonlinear Schrödinger equation are derived, respectively. With the help of these solutions, the effects of dissipation and external forcing on the evolution of envelope solitary Rossby wave are also discussed in detail. The results show that dissipation causes slowly decrease of amplitude of envelope solitary Rossby waves and slowly increase of width, while it has no effect on the propagation speed and different types of external forcing can excite the same envelope solitary Rossby waves. It is notable that dissipation and different types of external forcing have certain influence on the carrier frequency of envelope solitary Rossby waves.  相似文献   
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Using the intensity distribution of interference fringes formed by a capillary filled with transparent liquid, the variations in refractive index (RI) of nonlinear optical materials, corresponding to change of the intensity at the centre of fringes for a period, were deduced. With this conclusion, we measured variations in RI of ethyl red (ER) solution excited by a 535-nm-15 mW-laser, and found that the change of RI is 0.00504 and the corresponding effective index of refraction is −1.06 × 10−9, for which the order of magnitude is same as that measured by Z-scan. The influences on the accuracy of the method, such as temperature, beam and fringe contrast, were analyzed. This is a novel and simple method for measuring the RI of nonlinear optical materials.  相似文献   
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