Figure 1.Cross section of human skin, showing the approximate locations of the different mechanoreceptors.The sensor replicates the papillae structures in the human skin using an array of short pin-like nodules on the underside of its skin-like membrane. Figure 2 shows the sensor architecture and illustrates the sensor concept, where the papillae are deflected as the result of surface deformation. The opaque skin-like membrane consists of a 40 mm diameter hemisphere of 0.3mm thick, black, Shore hardness A 50 urethane, which provides a flexible but strong and relatively inelastic layer. The array of papillae-like nodules is moulded onto the internal surface of this skin layer, with the tips colored white to aid localization on the black membrane background.
This epidermal surface encloses a clear, highly compliant polymer that mimics the dermis and subcutaneous fat in the human finger whilst allowing the underside of the membrane to be viewed through a camera. The artificial skin layers have similar mechanical responses to indentation and shear as the human finger pad but they do not exhibit as much hysteresis. A more non-elastic sensor filling could be attractive for providing greater skin curvature and therefore papilla deflection during interactions, especially with soft elastic objects, although that is not the focus of this performance evaluation. When an object interacts with the sensing surface, changes in the surface gradient of the sensor membrane cause displacement of the white papillae tips on the underside. A CCD camera is used to capture the positions of the white papillae tips.
The camera Brefeldin_A is mounted at a distance of approximately 50 mm from the centre of the membrane in order to capture the w
Metal oxide semiconductors with wide band gaps have many important applications in the optics, electric and electronic industries. Transparent SnO2 thin films have been widely used in the production of transparent electrodes, far-infrared detectors, solar cells and gas sensors [1�C4]. Nanocrystalline SnO2 thin films have also garnered attention since higher quality synthesis of SnO2 thin films was achieved.A variety of methods, such as magnetron sputtering [5], vacuum evaporation [6], sol-gel [7], chemical vapor deposition [8], and sonochemistry [9] have been employed to prepare SnO2 thin films.
Among all the methods, the chemical bath deposition technique is very attractive because it is easy to control the growth factors, and crystal quality [10].Since in the CBD method several effective parameters such as concentration, time, temperature and the pH of the solution exist, too many experiments must be performed for finding the optimum conditions. Besides laborious experimental management, this also requires more chemicals, instruments and labor time.