Analysis of laser radiation using the Nonlinear Fourier transform

Modern high-power lasers exhibit a rich diversity of nonlinear dynamics, often featuring nontrivial co-existence of linear dispersive waves and coherent structures. While the classical Fourier method adequately describes extended dispersive waves, the analysis of time-localised and/or non-stationary signals call for more nuanced approaches. Yet, mathematical methods that can be used for simultaneous characterisation of localized and extended fields are not yet well developed. Here, we demonstrate how the Nonlinear Fourier transform (NFT) based on the Zakharov-Shabat spectral problem can be applied as a signal processing tool for representation and analysis of coherent structures embedded into dispersive radiation. We use full-field, real-time experimental measurements of mode-locked pulses to compute the nonlinear pulse spectra. For the classification of lasing regimes, we present the concept of eigenvalue probability distributions. We present two field normalisation approaches, and show the NFT can yield an effective model of the laser radiation under appropriate signal normalisation conditions

All-depth dispersion cancellation in spectral domain optical coherence tomography using numerical intensity correlations

In ultra-high resolution (UHR-) optical coherence tomography (OCT) group velocity dispersion (GVD) must be corrected for in order to approach the theoretical resolution limit. One approach promises not only compensation, but complete annihilation of even order dispersion effects, and that at all sample depths. This approach has hitherto been demonstrated with an experimentally demanding ‘balanced detection’ configuration based on using two detectors. We demonstrate intensity correlation (IC) OCT using a conventional spectral domain (SD) UHR-OCT system with a single detector. IC-SD-OCT configurations exhibit cross term ghost images and a reduced axial range, half of that of conventional SD-OCT. We demonstrate that both shortcomings can be removed by applying a generic artefact reduction algorithm and using analytic interferograms. We show the superiority of IC-SD-OCT compared to conventional SD-OCT by showing how IC-SD-OCT is able to image spatial structures behind a strongly dispersive silicon wafer. Finally, we question the resolution enhancement of 2–? that IC-SD-OCT is often believed to have compared to SD-OCT. We show that this is simply the effect of squaring the reflectivity profile as a natural result of processing the product of two intensity spectra instead of a single spectrum

Functionality of air defense units in JTLS simulation system

Przedmiotem badań stanowiących podstawę do powstania niniejszego artykułu był proces wspomagania komputerowego ćwiczeń dowódczo-sztabowych – przez wzgląd na udział w nich wojsk obrony przeciwlotniczej. Celem przeprowadzonych badań, których wyniki zaprezentowano, było – w ujęciu poznawczym – zebranie, usystematyzowanie i poszerzenie wiedzy w obszarze wykorzystania nowoczesnych technologii, w tym systemów symulacyjnych, w kontekście ćwiczeń dowódczo-sztabowych wspomaganych komputerowo. W ujęciu pragmatycznym – było to zdefiniowanie podstawowych parametrów taktyczno-technicznych sprzętu wojskowego oraz możliwości bojowych wojsk obrony przeciwlotniczej, których rzeczywiste modele mogą być wiernie odwzorowane w systemie symulacyjnym JTLS.The purpose of this article is to present more closely the subject of computer assisted exercises from the point of view of air defense units. The cognitive aim of the study is to gather, systematise and broaden the knowledge in the area of the use of modern technologies, including JTLS simulation system. In pragmatic terms – the result of the study was to define the basic tactical-technical parameters of military equipment and combat capabilities of air defense units, whose real models can be faithfully represented in the simulation system

Investigations on hydrogenation of selected organic sulfur compounds on the Ni-Mo/Al2\text{}_{2}O3\text{}_{3}catalyst in terms of natural gas desulfurization

Technological problems of natural gas desulfurization in syngases manufacturing plants have been discussed and the results of investigations on the activity of the model Ni-Mo/Al$\text{}_{2}$O$\text{}_{3}$ catalyst in hydrogenation of selected sulfur compounds have been presented. The HDS reaction rate is dependent on a compound structure. The hydrogenation rate on the Ni-Mo/Al$\text{}_{2}$O$\text{}_{3}$ catalyst for the given sulfur compound increases in the order: CS$\text{}_{2}$(CH$\text{}_{3}$)$\text{}_{2}$S>C$\text{}_{4}$H$\text{}_{10}$S>C$\text{}_{2}$H$\text{}_{6}$S$\text{}_{2}$C$\text{}_{4}$H$\text{}_{4}$S

Production of hydrogen over Ni/carbonaceous catalyst

Catalytic materials for hydrogen production were synthesized by impregnating waste spruce sawdust with nickel nitrate followed by microwave pyrolysis. Ni/carbonaceous materials thus obtained were tested as catalyst for dry reforming of methane as well as for upgrading of organic vapours from biomass pyrolysis. Among five samples synthesized with different amount of Ni on carbonaceous support, the sample with 13.2 wt% Ni showed the highest CH4 and CO2 conversion for dry reforming at 800 degrees C. The yields of 31.4 vol% for H-2 and 39.0 vol% for CO were recorded. The catalyst sample exhibited only a small decrease in activity after 6 h of time-on-stream. The same sample was applied as catalyst for upgrading of organic vapours from thermal pyrolysis of spruce sawdust and cellulose. A considerable increase in H-2 content (i.e. from 1.2 to 14.1 mmol g(-1)) in the product mixture was observed. The main advantage of using carbonaceous support is its resistance towards rapid deactivation due to coke deposition. This advantage can be exploited by using it as catalyst support in reactions that suffer from such catalyst deactivation. Furthermore, the honeycomb-like structure and morphology of carbonaceous materials can promote mass transfer around catalytically active sites that can be beneficial in reactions involving large molecules.Web of Science278art. no. 11839

Prediction of Incomplete Response of Primary Tumour Based on Clinical and Radiomics Features in Inoperable Head and Neck Cancers after Definitive Treatment

Radical treatment of patients diagnosed with inoperable and locally advanced head and neck cancers (LAHNC) is still a challenge for clinicians. Prediction of incomplete response (IR) of primary tumour would be of value to the treatment optimization for patients with LAHNC. Aim of this study was to develop and evaluate models based on clinical and radiomics features for prediction of IR in patients diagnosed with LAHNC and treated with definitive chemoradiation or radiotherapy. Clinical and imaging data of 290 patients were included into this retrospective study. Clinical model was built based on tumour and patient related features. Radiomics features were extracted based on imaging data, consisting of contrast- and non-contrast-enhanced pre-treatment CT images, obtained in process of diagnosis and radiotherapy planning. Performance of clinical and combined models were evaluated with area under the ROC curve (AUROC). Classification performance was evaluated using 5-fold cross validation. Model based on selected clinical features including ECOG performance, tumour stage T3/4, primary site: oral cavity and tumour volume were significantly predictive for IR, with AUROC of 0.78. Combining clinical and radiomics features did not improve model’s performance, achieving AUROC 0.77 and 0.68 for non-contrast enhanced and contrast-enhanced images respectively. The model based on clinical features showed good performance in IR prediction. Combined model performance suggests that real-world imaging data might not yet be ready for use in predictive models