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Laser-induced fluorescence spectroscopy (LIFS) is actively used for remote sensing of atmospheric aerosols and is currently one of the most sensitive and selective techniques for determining small concentrations of substances inside particles. The use of high-power femtosecond laser sources for LIFS-based remote sensing of aerosols contributes to the development of new-generation fluorescence atmospheric lidars since it makes it possible to overcome the energy threshold for the nonlinear-optical effects of multiphoton absorption in particles and receive the emission signal at long distances in the atmosphere. Our study is aimed at the development and experimental demonstration of the technique of nonlinear laser-induced fluorescence spectroscopy (NLIFS) based on the remote excitation of aerosol fluorescent emission stimulated by a spatially structured high-power femtosecond laser pulse. Importantly, for the first time to our knowledge, we demonstrate the advances in using stochastically structured plasma-free intense light channels (postfilaments) specially formed by the propagation of femtosecond laser radiation through a turbulent air layer to improve NLIFS efficiency. A multiple increase in the received signal of two-photon-excited fluorescence of polydisperse-dyed aqueous aerosols by the structured postfilaments is reported. [ABSTRACT FROM AUTHOR]

The purpose of the research is to determine the effect of ammonium nitrate fertilizer on the growth and yield of Origanum vulgare L. essential oil grown in Northern Kazakhstan. One-factor analysis proved that the introduction of ammonium nitrate positively affected the growth and yield of O. vulgare L., the yield of essential oil and the content of its individual components. Plant height increased by 19.3%, bush size - by 17.4%, yield - by 11.8%. Essential oil output of O. vulgare L. at the experimental site, compared to the control site, increased by 20% and the yield of extraction reached 0.60% and 0.48%, respectively. The largest number of components was related to monoterpenes (52.57% in the experimental section, -50.10% in the control section), the most common were γ-Terpinene, ß-Sabinene, Carvacrol and trans-ß-Ocimene. Sesquiterpene content in the experimental sample was 37.19%, compared to 38.5250% in the control sample, in which Germacrene D and Caryophyllene were the most common components. Cluster analysis showed that the essential oil composition of O. vulgare L. from Kazakhstan is similar to the composition of the essential oil of plants from Moldova, Poland, Turkey (Anatolia), Latvia and Russia. Germacrene D, Carvacrol and ß-Sabinene were the binding components of plants from Kazakhstan and Moldova. The similarity between plants from Kazakhstan and other countries in the same cluster was due to the Germacrene D content (cluster's average value was 10.1%) and the content of Spathulenol (4.9%). [ABSTRACT FROM AUTHOR]