The article presents certain general conclusions obtained from an investigation of a vibration-powered milli- or microgenerator functioning as a harvester. In this context, the authors summarize the parameters that are critical in designing optimal generators to retrieve the residual energy contained in an electromechanical system and transferred through the vibrations of an independent structure. The discussion exploits our previous results, which theoretically define the properties characterizing the models of individual basic configurations of a generator based on Faraday’s law of induction.
The authors discuss the application of a broadband noise signal in the research of periodic structures and present the basic testing related to the described problem. Generally, noise spectroscopy tests are carried out to verify the behaviour of the response of periodic structures, and the related objective consists in recording the properties of microscopic structures in natural and artificial materials. The aim is to find a metrological method to investigate structures and materials in the frequency range between 100 MHz and 10 GHz; this paper therefore characterizes the design of a suitable measuring technique based on noise spectroscopy and introduces the first tests conducted on a periodic structure. In this context, the applied instrumentation is also shown to complement the underlying theoretical analysis.
The paper discusses a numerical model and provides an analysis of a graphene coaxial line suitable for sub-micron sensors of magnetic fields. In relation to the presented concept, the target areas and disciplines include biology, medicine, prosthetics, and microscopic solutions for modern actuators or SMART elements. The proposed numerical model is based on an analysis of a periodic structure with high repeatability, and it exploits a graphene polymer having a basic dimension in nanometers. The model simulates the actual random motion in the structure as the source of spurious signals and considers the pulse propagation along the structure; furthermore, the model also examines whether and how the pulse will be distorted at the beginning of the line, given the various ending versions. The results of the analysis are necessary for further use of the designed sensing devices based on graphene structures.
The authors propose an analysis of a model solar element based on the principle of a resonance system
facilitating the transformation of the external form of incident energy into electrical energy. A similar principle provides
the basis for harvesters designed to operate at lower frequencies, Jirků T., Fiala P. and Kluge M.,2010, Wen J.L., Wen
Z., Wong P.K., 2000. In these harvesters, the efficiency of the energy form transformation can be controlled from the
frequency spectrum of an external source (the Sun).
The paper presents two example approaches to energy harvesting. Mechanical energy harvesting system is based on
vibrational minigenerator. Basic relations of its analytical model are given in order to obtain an idea about the operating
conditions. Electromagnetic harvesting system is based on tuned resonant nano-structure. Its concepts allows impedance
matching in order to operate in given frequency range. The matching properties are verified by means of numerical finite
element analysis. For power management of vibration energy harvesting system several circuit design concepts are
presented together with simulation results and basic properties comparison.
Spatial imaging is nowadays realized using a number of principles and technologies. Application of
stereography in combination with the diffractive structures is thus only one of many possible solutions.
We introduce two methods of synthetic stereography using diffractive structures. The two-step method
of holographic stereography records a 2D matrix of primary holograms in its first step, using an original
recording device. This multiplexed master is then reconstructed in a typical holographic scheme and
a full-color rainbow hologram can be recorded in the second step. The second presented method,
the method of direct writing, records the diffractive structure of a full-color synthetic stereogram
in a single step, using an optical lithograph. The recorded structure is composed of elementary
diffraction gratings and is completely calculated using a computer. Benefits and specific problems of
both methods are discussed.