Two-dimensional lead halide perovskites have demonstrated their potential as high-performance scintillators for X- and gamma-ray detection, while also being low-cost. Here we adopt lithium chemical ...doping in two-dimensional phenethylammonium lead bromide (PEA)
2
PbBr
4
perovskite crystals to improve the properties and add functionalities with other radiation detections. Li doping is confirmed by X-ray photoemission spectroscopy and the scintillation mechanisms are explored via temperature dependent X-ray and thermoluminescence measurements. Our 1:1 Li-doped (PEA)
2
PbBr
4
demonstrates a fast decay time of 11 ns (80%), a clear photopeak with an energy resolution of 12.4%, and a scintillation yield of 11,000 photons per MeV under 662 keV gamma-ray radiation. Additionally, our Li-doped crystal shows a clear alpha particle/gamma-ray discrimination and promising thermal neutron detection through
6
Li enrichment. X-ray imaging pictures with (PEA)
2
PbBr
4
are also presented. All results demonstrate the potential of Li-doped (PEA)
2
PbBr
4
as a versatile scintillator covering a wide radiation energy range for various applications.
Two-dimensional lead halide perovskites have shown great potential as X- and γ-ray scintillators due to their high light yield, fast decay rate, and low fabrication cost. Here, their versatility is expanded by achieving, via Li-doping,
α
-particle/γ-ray discrimination and thermal neutron detection.
Optical and scintillation characteristics of Mg2+-codoped Lu2Y(Al5-xGax)O12:Ce (x = 2, 3) multicomponent garnet crystals grown by the micro-pulling down method were investigated. At RT, the ...shortening of scintillation decay time and a decrease of light yield (LY) value measured for a higher Ga containing samples can be explained by thermal ionization of the Ce3+ 5d1 excited state. At 662 keV γ-rays, Lu2YAl3Ga2O12: Ce, 0.05%Mg exhibits high LY value of 29,000 ph/MeV along with scintillation decay times of 50 ns (86%) + 73 ns (14%). Co-doping with larger Mg2+ content leads to a decrease of LY value, scintillation decay time, and afterglow level. Radioluminescence quenching observed at low temperature region in correlation with large thermoluminescence peaks can be caused by trapping of electrons at intrinsic shallow traps.
•Luminescence and scintillation properties of Lu2Y(Al5-xGax)O12:Ce,Mg (x = 2, 3) crystals are investigated.•Temperature dependencies of photo-and radioluminescence are presented.•Lu2YAl3Ga2O12:Ce,0.05%Mg shows high light yield of 29,000 photons/MeV.•Lu2YAl3Ga2O12:Ce,0.05%Mg shows quenching temperature at 435 K due to thermal ionization.•Afterglow and thermoluminescence characteristics are investigated.
Holographic projectors and near-eye displays are a promising technology with truly three-dimensional, natural viewing and excellent energetic efficiency. Spatial light modulators with periodic pixel ...matrices cause image duplicates, which distract the viewer and waste energy of the playback beam. We present the engineering of the far field intensity envelope, which suppresses higher-order image duplicates in the simplest possible optical setup by physically changing the shape of modulator pixels with attached apodizing masks. Numerical and experimental results show the limited number of perceived duplicates and better uniformity in off-axis projections for the price of compromised energetic efficiency due to amplitude masks.
In this work an original construction of a vibration damper controlled by means of a valve with a short time of operation lag is presented. The valve-controlling properties of the damper regulates ...the flow of fluid between the chambers of the damper and was constructed using piezoelectric actuators, whose characteristic feature is the possibility to change dimensions, e.g., length, under the influence of voltage. As a result, by changing voltage it is possible to control the throttle of the flow by changing the width of a gap, which influences a change of damping forces. Such a solution enables a quicker change of damping forces than in other kinds of controlled damper. Due to the obtained properties, the damper may be applied to reduce the vibrations of vehicles and machines that undergo quick-change loads. In the article, the results of experimental studies of the aforementioned damper are presented. Based on the results, dissipative characteristics were determined. Also, results of numerical studies comprising the development of a numerical model of a controlled piezoelectric damper are shown. Results of numerical studies, as well as experimental studies, are presented in the form of dissipative characteristics. Comparison of results of numerical and experimental studies confirms the possibility to apply this kind of construction in semi-active systems of vibration reduction of vehicles and machines.
Czochralski-grown β-Ga2O3 and β-Ga2O3:Si crystals with the free electron concentrations between 2.5·1016 and 4.3·1018 cm−3 have been characterized by means of pulse height and scintillation time ...profile measurements in order to assess their basic scintillation properties. At room temperature, with increasing free electron concentration in the studied range, the scintillation yields decrease from 8920 to 1930 ph/MeV, while the mean scintillation decay times pare down from 989 to 61 ns. However, when the brightest β-Ga2O3 sample is cooled down below 100 K, its scintillation yield exceeds 20000 ph/MeV.
•Czochralski-grown β-Ga2O3 and β-Ga2O3:Si crystals have been characterized.•Scintillation yield and decay times strongly depend on free electron concentration.•Scintillation yield clearly goes up with decreasing temperature towards liquid N2.
Zinc oxide (ZnO) is one of the wide-bandgap semiconductors, which may be useful in a plethora of electronic, optical, piezoelectric, and scintillating applications. The following article consists in ...a structural and luminescence analysis of ZnO microfilms grown on a sapphire substrate with a sol–gel method. The films were annealed at different temperatures. The structures were investigated with the XRD and Raman methods, by which the influence of the substrate on the structure of the film was determined. The luminescence of films was investigated with room-temperature fluorescence, radioluminescence, and thermoluminescence.
W artykule opisano zakres zastosowania sztucznej inteligencji w procesie komunikacyjnym. Szczególną uwagę poświęcono technologii botów wykorzystywanych w nowych mediach. Przybliżono funkcjonalność ...tych rozwiązań w turbulentnych warunkach rynkowych, wskazując zarówno ich działania pozytywne, jak i negatywne w burzliwych warunkach komunikacyjnych. Autor wskazał zalety i wady praktycznych zastosowań sztucznej inteligencji w nowych mediach oraz perspektywy doskonalenia tych rozwiązań komunikacyjnych.The paper presents the scope of application of artificial intelligence in the communication process. Particular attention was paid to the technology of bots used in new media. The functionality of these solutions in turbulent market conditions has been described, indicating both their positive and negative effects in turbulent communication conditions. The Author pointed out the advantages and disadvantages of practical applications of artificial intelligence in new media and the prospects for improving such communication possibilities.
In this paper, an original construction of a vehicle vibration damper controlled by means of a valve based on piezoelectric actuator is presented and investigated. The presented valve allows us to ...control dissipation characteristics of the damper faster than in other solutions adjusting the size of the gap through which the oil flows between the chambers of the damper. The article also presents the results of the experimental investigation of the above-mentioned damper showing the possibility of changing the value of the damping force five times in about 10 ms by changing the voltage supplying the piezoelectric actuator. Based on these results, dissipative characteristics were determined which enabled the identification of the parameters of the damper numerical model. The article also presents the results of numerical investigations a vehicle model equipped with the developed dampers. The results showed that the developed damper controlled by the use of the piezoelectric actuator can significantly affect vehicle traffic safety by reducing the variation of vertical forces acting on the wheels. The results obtained are so promising that the authors undertook preparations to conduct road tests of a vehicle equipped with the developed dampers.
Low temperature thermoluminescence of β-Ga2O3, β-Ga2O3:Al and β-Ga2O3:Ce has been investigated. Glow curves have been analyzed quantitatively using a rate equations model in order to determine the ...traps parameters, such as activation energies, capture cross-sections and probabilities of recombination and retrapping.
•Undoped and doped β-Ga2O3 crystals have been grown by the Czochralski method.•Their glow curves between 10 and 350 K have been investigated.•Rate equations model has been used to determine traps parameters.
The paper presents knowledge of the structure of the content of an advertising message and the perception of the used content, with particular emphasis on the limitations of rationality in the ...decision-making process. The operation of information processing mechanisms and the process of using heuristics to automate the perception of content were discussed. The Author indicated the possibility of using perception maps to assess the effectiveness of an advertising message. Keywords: advertising, advertising message, heuristics, persuasion of the message, perception map.
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