Contact free potential mapping by vibrating capacitor
The contact free vibrating capacitor method is a valuable tool for investigating the surface potentials of solid surfaces. The purpose of the present article is to summarize the theory and capabilities of the vibrating capacitor method, especially scanning vibrating capacitor pictures in the electronics. After a brief review some results will be discussed, such as a contact potential map taken from a printed circuit board, a surface potential map from a biased ceramic thick film circuit and some results from silicon solid state devices and solar cells. Potential maps contain a lot of information concerning the surface conditions, included the inhomogeneities of the technology, bias and other additional excitation. These potential maps may help in the development, quality control and defect analysis
Chemical imaging by direct methods
Chemical imaging is a very old principle of analysis. It has been used for many millions of years in biological tasting and smelling systems. Artificial versions of chemical imaging are traditional paper chromatography and the pH indicator strip used in chemical analysis, which directly result in real (visible) chemical images. In a recent article the indirect and direct chemical imaging methods are introduced, especially the evaluation methods for gas sensitive surfaces by direct pixelizing of the surface and interface potential changes. The scanned light pulse technique (SLPT) and the scanning vibrating capacitor are very effective tools for the chemical mapping of the surfaces. These methods are sensitive for the interface or surface potential shifts (adsorption induced work function shifts) respectively, that depend on the composition of adsorbed layers. Advantages and disadvantages, some technical limits, theory, practice and some results are discussed, too.
Monitoring and Optimization of Internal Grinding Process
Summary The grinding process is influenced by many factors such as grinding wheel characteristics, dressing conditions and, course, grinding conditions. Therefore, it is difficult to perform the grinding operation in an optimum state. In this study, in-process monitoring methods using power and acoustics emission sensors are proposed to detect malfunctions in the internal grinding process. In addition, a new internal grinding cycle featuring rapid indeed is proposed to minimize the grinding cycle time.