Experimental Aspects of Holographic Projection with a Liquid-Crystal-on-Silicon Spatial Light Modulator

Dynamic electroholography is a suitable and promising technology of image display for future projection and near-eye displays. Until a new phase modulation technology is introduced, practical research assumes the use of pixelated spatial light modulators based on liquid crystals with electronically controlled birefringence leading to a controllable refractive index. Such an approach allows for university grade development and testing of holographic computation methodology, but its limitations and drawbacks currently disable the massive application in consumer electronics. This chapter describes the differences between the behavior of the modulator as expected from Fourier optics and that observed in practical optical experiments. Moreover, practical hints and proven techniques of overcoming selected hardware issues of the chosen liquid-crystal-on-silicon (LCoS) phase modulators are given. The smart combination of the described techniques could allow more precise operation of spatial light modulators with a higher agreement with numerical simulations, especially for holographic projection of colorful images

Mathematical model for two-dimensional dry friction modified by dither.

A new dynamic two-dimensional friction model is developed which is based on the bristle theory. Actually it is the Reset Integrator Model converted into a two-dimensional space. Usually two-dimensional friction models are indeed onedimensional models which are rotated into the slip velocity direction. However, this often used approach cannot be applied to the bristle model. That is why an idea of a two-dimensional bristle is presented. Bristle’s deformation is described using polar coordinates. The carried out numerical simulation of a planar oscillator has proved that the new model correctly captures the mechanism of smoothing dry friction by dither applied via perpendicular and co-linear way regarding the body velocity. Furthermore, the introduced mathematical model captures two-dimensional stick-slip behaviour. The Cartesian slip velocity components are the only inputs to the model. In addition, our proposed model allows to describe a friction anisotropy using the bristle parameters. The paper contains results of an experimental verification of the new friction model conducted on the special laboratory rig being used to investigate the two dimensional motion in the presence of dither as well as to validate our numerical results

Reconstructing stability : the role of education in post-conflict territorial transitions : a case study of Szczecin after World War II

PURPOSE: The aim of the article is to attempt to create a collective portrait of teachers in the conditions of population shifts on the Polish-German borderland after World War II.DESIGN/METHODOLOGY/APPROACH: The method involves statistical analysis of data from archival materials, memoirs of participants, and literature allowing for the creation of a collective portrait of the community. The argumentation is based on the analysis of the collective of teachers of the first high school in Szczecin established after World War II. The findings allow for generalizations to be made about the entire teaching community, both in Polish territories and other areas affected by population exchange due to armed conflict.CONCLUSIONS: The presented example allows us to conclude that the establishment of educational institutions is essential for creating conditions for settlement, but at the same time, teachers from settlement groups exhibit similar characteristics to the entire migratory population.PRACTICAL IMPLICATIONS: Practical implications for decision-makers and researchers of migration processes and the effectiveness of state policy in shaping social structures.ORIGINALITY/VALUE: The presented issue has not been subject to scientific analysis before.peer-reviewe

Wypłaty dywidend w spółkach z udziałem zagranicznych inwestorów bezpośrednich

Dochody inwestorów bezpośrednich (głównie dywidendy) od lat stanowią istotną część ujemnego salda obrotów bieżących bilansu płatniczego. Autorzy podjęli się zadania weryfikacji wymienianych w literaturze przedmiotu czynników, wpływających na decyzje o wypłacie dywidend w przedsiębiorstwach z udziałem zagranicznego inwestora bezpośredniego, pod względem ich istotności i kierunku oddziaływania. W badaniu obejmującym lata 2012–2014, oszacowano tobitowe modele dla danych panelowych, uwzględniające m.in. finansowanie długiem. Analizę oparto na zbilansowanym panelu obejmującym 3437 jednostek

Recent Progress in the Development of β-Ga2O3 Scintillator Crystals Grown by the Czochralski Method

A high-quality bulk single crystal of β-Ga2O3 has been grown by the Czochralski method and its basic scintillation characteristics (light yield, energy resolution, proportionality, and scintillation decay times) have been investigated. All the samples cut from the crystal show promising scintillation yields between 8400 and 8920 ph/MeV, which is a noticeable step forward compared to previous studies. The remaining parameters, i.e. the energy resolution slightly above 10% (at 662 keV) and the scintillation mean decay time just under 1 μs, are at the same level as we have formerly recognized for β-Ga2O3. The proportionality of yield seems not to deviate from standards determined by other commercial scintillators

Recent progress in the development of β-Ga2O3 scintillator crystals grown by the Czochralski method

A high-quality bulk single crystal of β-Ga2O3 has been grown by the Czochralski method and its basic scintillation characteristics (light yield, energy resolution, proportionality, and scintillation decay times) have been investigated. All the samples cut from the crystal show promising scintillation yields between 8400 and 8920 ph/MeV, which is a noticeable step forward compared to previous studies. The remaining parameters, i.e. the energy resolution slightly above 10% (at 662 keV) and the scintillation mean decay time just under 1 μs, are at the same level as we have formerly recognized for β-Ga2O3. The proportionality of yield seems not to deviate from standards determined by other commercial scintillators

Tailoring the Scintillation Properties of β-Ga2O3 by Doping with Ce and Codoping with Si

Measurements of pulse height spectra and scintillation time profiles performed on Czochralski-grown β-Ga2O3, β-Ga2O3:Ce, and β-Ga2O3:Ce,Si crystals are reported. The highest value of scintillation yield, 7040 ph/MeV, was achieved for pure β-Ga2O3 at a low free electron concentration, nevertheless Ce-doped crystals could also approach high values thereof. Si-codoping, however, decreases the scintillation yield. The presence of Ce, and the more of Ce and Si, in β-Ga2O3 significantly increases the contribution of the fastest components in scintillation time profiles, which makes β-Ga2O3 a very fast scintillator under γ-excitation