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Some results in characterization of two contact MEMS position sensors with sidewall piezoresistors are presented. Devices with in-plane travel range of about 50pm comprise of one and the same symmetrical transducer with two Π-shaped flexures. For first time, just by means of different configuration of the same sidewall piezoresistors in the same flexures, position sensors which are selectively sensitive in X or Y direction were prototyped and tested. Experimentally measured ratio of the displacement sensitivities in Y vs. X direction of the first type sensor was 16.5 and same ratio of the sensitivities in X vs. Y direction of the second type was 27.6.

This paper presents a training course on practical aspects in design, technology and prototype fabrication of microsystems with piezoresistive feedback, exploiting the shared infrastructure. The course content is considered in the scope of building a sustainable Knowledge Alliance between the partners in Erasmus+ Project# 562206-EPP-1-2015-1-BG-EPPKA2-KA — MECA.

We report the fabrication of buried contact solar cells using porous silicon as sacrificial layer to create well-defined channels (for buried contacts) in silicon. In this paper, the salient features of the technology have been presented. No detrimental effect was found in the performance of buried contact solar cell with partially filled contact area compared to the solar cells having conventional planar contacts. However, a marked difference in the short circuit current density was seen when channel was fully filled with metal by screen printing, without degradation in the open-circuit voltage. It is expected that improved processing in combination with optimized buried metallic contact parameters may yield higher efficiencies that may result in substantial decrease in solar cell cost.

A model of a random field of the momenta of impact forces acting on a plane surface treated with a water‐drop jet has been developed. Based on the calculation and experimental data, it is shown that the action of individual drops is statistically independent in time and coordinates.

The influence of displacements of tensioned fibers on the impregnation of fibrous layers with a polymer melt and on the final composite structure is studied. Using computer simulation, it is shown that, during impregnation, the structure of tensioned fibrous layers changes considerably depending on the initial arrangement and tensioning of fibers. The consolidated regions formed under the melt front move inside the impregnated layer with the advancing melt front. Displacement of the tensioned fibers as well as the formation of “washouts” favors the impregnation of internal layers, but cause significant inhomogeneity of the polymer structure. The surface (on the side of the melt flow) regions are more saturated with the polymer than the internal ones. A difference in the melt percolation mechanisms at various impregnation regimes is revealed. The effective permeability coefficients of a tensioned fiber layer are not constant but depend on the conditions and regimes of impregnation.

The solution of the problem of the percolation of a nonlinearly viscous (with a power flow law) fluid through unit cells is used to find the dependence of the permeability coefficient of a unidirectional layer of fibers on fiber concentration, parameters characterizing the location of the fibers, and the parameters of the fluid (the exponent in the flow law) for random and regular fiber configurations in the transverse plane. It is established that the degree of nonuniformity of the pore space of the layer has a significant effect on its permeability and that this effect increases with an increase in the nonlinearity of the fluid. Data from a model experiment and computer simulation are used to describe the mechanism of transformation of the pore space by the fluid front. It is shown that consolidation of the layer also affects its permeability.

The aim of this study was formation of a multilayered transparent conductive nanolaminate structure with optimized conductivity vs. transparency parameters. The nanolayered structure comprised one or two thin layers of dielectric materials. The overall electrical conductivity was modified by tuning the size of the planar metal granules. Magnetron sputtering system with three different targets was used for layers deposition. The advantages are: the good reproducibility of a low-temperature process allows for effective process control and, optionally, selective formation of conductive areas in a dielectric structure. Our studies revealed that the relation between the sheet resistance and the maximum transparency in the visible spectral range depends on the size of the metal granules and the film thickness of the dielectric coating. The technology provides transparent conductive coatings with well-controlled optical and electrical properties.

The paper investigates tense and deformed states of glass fibre and bonding component in a unidirectional glas plastic in relation to the arrangement of fibres in th transversal section and applid external load. Regularitie in the distribution of random tensions and deformations i components at orderly and haphazard arrangement of fibre are established through computeraided modelling. The de pendence of the probability of microdeformation incidenc upon the structure of the material under a random ten sion is inferred. The paper also attempts to explain som of the pecularities of fracture of unidirectional fibe glass plastic at a microstructural level.

Etude des proprietes physique et electrique du silicium dope par implantation ionique au phosphore et recuit par illumination flash. Les couches implantees sont completement activees sans diffusion notable. En utilisant des couches fortement dopees, on peut former des jonctions p-n tres superficielles