Determination of electric potential difference using the Kelvin probe, i.e. vibrating capacitor technique, is one of the most sensitive measuring procedures in surface physics. Periodic modulation of distance between electrodes leads to changes in capacitance, thereby causing current to flow through the external circuit. The procedure of contactless, non-destructive determination of contact potential difference between an electrically conductive vibrating reference electrode and an electrically conductive sample is based on precise control measurement of Kelvin current flowing through a capacitor. The present research is devoted to creation of a new low-cost miniaturised measurement system to determine potential difference in real time and at high measurement resolution. Furthermore, using the electrode of a reference probe, the Kelvin method leads to both the indirect measurement of an electronic work function, or a contact potential of sample, and of a surface potential for insulator type samples.
In the article, the first part of the research, i.e., the basic principles and prerequisites for establishment of such a measurement system are considered.
This paper studies how a spherical magnetizable body interacts with a magnetic fluid layer on a horizontal plane in a uniform vertical magnetic field. It is experimentally shown that the body can move along the magnetic fluid layer. A theoretical analysis takes into account gravity and viscous friction. The impact of the problem parameters on the magnetic force acting on the body from the layer is investigated, and it is shown that the body can be either attracted or repelled by the magnetic fluid layer.
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