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Chemical stresses induced in the boundary layer of a B/A/B sandwiched slab during diffusion were analyzed. Both the cases of constant surface concentration source and instantaneous surface concentration source were considered. The diffusivity of diffusant is much greater in the central layer than the outer layers. The concentration of diffusant in the sandwiched slab was obtained using the Laplace-Fourier transformation technique. Assuming that the stresses developed in the outer layers were negligibly small during the boundary layer diffusion, the stresses developed in the central layer were determined based on the Moutier cycle theorem. Numerical results were performed to illustrate the effect of diffusivity ratio of diffusant in the central layer to that in the outer layers and of specimen size on stress variation. [ABSTRACT FROM AUTHOR]

We show the feasibility of copper electroplating using graphene as a seed layer. Thermal annealing of the as-plated copper-graphene hybrid system promotes permeation of copper into graphene, forming an intermixing layer with enlarged lattice constant. It is shown that this intermixing layer blocks the diffusion of copper into the bottom SiO2/Si substrate at temperatures up to 900 C. The electroplating process is comparable with current semiconductor fabrication technology. This hybrid system can serve as interconnect in the integrated circuits. [ABSTRACT FROM AUTHOR]

A pendant drop tensiometer, coupled with image digitization technology and a best-fitting algorithm, was built to accurately measure the surface tension of glass melts at high temperatures. More than one thousand edge-coordinate points were obtained for a pendant glass drop. These edge points were fitted with the theoretical drop profiles derived from the Young-Laplace equation to determine the surface tension of glass melt. The uncertainty of the surface tension measurements was investigated. The measurement uncertainty (σ) could be related to a newly defined factor of drop profile completeness (Fc): the larger the Fc is, the smaller σ is. Experimental data showed that the uncertainty of the surface tension measurement when using this pendant drop tensiometer could be ±3 mN/m for glass melts. [ABSTRACT FROM AUTHOR]

A modified selected-plane method for contact angle (theta) measurement is proposed in this study that avoids the difficulty of finding the real contact point and image-distortion effects adjacent to the contact point. This method is particularly suitable for superhydrophobic surfaces. The sessile-drop method coupled with the tangent line is the most popular method to find the contact angle in literature, but it entails unavoidable errors in determining the air-solid base line due to the smoothness problem and substrate tilting. In addition, the tangent-line technique requires finding the actual contact point. The measurement error due to the base line problem becomes more profound for superhydrophobic surfaces. A larger theta deviation results from a more superhydrophobic surface with a fixed base line error. The proposed modified selected-plane method requires only four data points (droplet apex, droplet height, and two interfacial loci close to the air-solid interface), avoiding the problem of the sessile-drop-tangent method in finding the contact point and saving the trouble of the sessile-drop-fitting method for best fitting of the numerous edge points with the theoretical profile. A careful error analysis was performed, and a user-friendly program was provided in this work. This method resulted in an accurate theta measurement and a method that was much improved over the classical selected plane and the sessile-drop-tangent methods. The theta difference between this method and the sessile-drop-fitting method was found to be less than three degrees.