Wrocław University of Technology

About: Wrocław University of Technology is a education organization based out in Wrocław, Poland. It is known for research contribution in the topics: Laser & Computer science. The organization has 13115 authors who have published 31279 publications receiving 338694 citations.

Asymptotic distributions of continuous-time random walks: A probabilistic approach

Abstract: We provide a systematic analysis of the possible asymptotic distributions o one-dimensional continuous-time random walks (CTRWs) by applying the limit theorems of probability theory. Biased and unbiased walks of coupled and decoupled memory are considered. In contrast to previous work concerning decoupled memory and Levy walks, we deal also with arbitrary coupled memory and with jump densities asymmetric about its mean, obtaining asymmetric Levy-stable limits. Suprisingly, it is found that in most cases coupled memory has no essential influence on the form of the limiting distribution. We discuss interesting properties of walks with an infinite mean waiting time between successive jumps.

Effect of the New Plant Growth Biostimulants Based on Amino Acids on Yield and Grain Quality of Winter Wheat.

Abstract: Field and laboratory experiments were carried out in 2012–2013, aimed at evaluating the influence of new products stimulating plant growth based on amino acids on crop yield, characteristics of grain and content of macro- and micronutrients in winter wheat (Triticum aestivum L.). The tests included two formulations produced in cooperation with INTERMAG Co. (Olkusz, Poland)—AminoPrim and AminoHort, containing 15% and 20% amino acids, respectively, and 0.27% and 2.1% microelements, respectively. Field experiments showed that the application of products based on amino acids influenced the increase of grain yield of winter wheat (5.4% and 11%, respectively, for the application of AminoPrim at a dose 1.0 L/ha and AminoHort at dose 1.25 L/ha) when compared to the control group without biostimulant. Laboratory tests showed an increase of technological characteristics of grain such as ash content, Zeleny sedimentation index and content of protein. The use of the tested preparations at different doses also contributed to the increase of the nutrients content in grains, in particular copper (ranging 31–50%), as well as sodium (35–43%), calcium (4.3–7.9%) and molybdenum (3.9–16%). Biostimulants based on amino acids, tested in the present study, can be recommended for an efficient agricultural production.

Revealing the nature of photoluminescence emission in the metal-halide double perovskite Cs2AgBiBr6

Abstract: Double perovskite crystals such as Cs2AgBiBr6 are expected to overcome the limitation of classic hybrid organic–inorganic perovskite crystals related to the presence of lead and the lack of structural stability. Perovskites are ionic crystals in which the carriers are expected to strongly couple to lattice vibrations. In this work we demonstrate that the photoluminescence (PL) emission in Cs2AgBiBr6 is strongly influenced by the strong electron–phonon coupling. Combining photoluminescence excitation (PLE) and Raman spectroscopy we show that the PL emission is related to a color center rather than a band-to-band transition. The broadening and the Stokes shift of the PL emission from Cs2AgBiBr6 is well explained using a Franck–Condon model with a Huang–Rhys factor of S = 11.7 indicating a strong electron–phonon interaction in this material.

Harmonically mode-locked Er-doped fiber laser based on a Sb2Te3 topological insulator saturable absorber

Abstract: In this letter we present for the first time, to the best of our knowledge, a harmonically mode-locked Er-doped fiber laser with antimony telluride (Sb2Te3) topological insulator material used as a saturable absorber (SA). The SA was prepared via mechanical exfoliation of the bulk material. The 80 nm thick Sb2Te3 layers transferred onto fiber ferrule entirely cover the fiber core. The Er-doped fiber mode-locked laser based on such SA generated optical pulses was centered at 1558 nm with 1.9 ps duration and a fundamental repetition rate of 3.75 MHz. Increasing the pump power results in stable harmonic mode-locked operation up to the 81st harmonic at 304 MHz repetition frequency. The laser was capable of generating optical solitons with 2.2 ps duration. The number of generated harmonics could be tuned only by changing the pump power injected into the laser cavity.