On elliptic solutions of the quintic complex one-dimensional Ginzburg-Landau equation

The Conte-Musette method has been modified for the search of only elliptic solutions to systems of differential equations. A key idea of this a priory restriction is to simplify calculations by means of the use of a few Laurent series solutions instead of one and the use of the residue theorem. The application of our approach to the quintic complex one-dimensional Ginzburg-Landau equation (CGLE5) allows to find elliptic solutions in the wave form. We also find restrictions on coefficients, which are necessary conditions for the existence of elliptic solutions for the CGLE5. Using the investigation of the CGLE5 as an example, we demonstrate that to find elliptic solutions the analysis of a system of differential equations is more preferable than the analysis of the equivalent single differential equation.Comment: LaTeX, 21 page

Nanostructuring of solid surfaces by femtosecond laser pulses

One-dimensional quasi-periodic structures whose period is much smaller than the wavelength of exciting optical radiation have been obtained on a titanium surface under the multi-shot action of linearly polarized femtosecond laser radiation at various surface energy densities. As the radiation energy density increases, the one-dimensional surface nanogratings oriented perpendicularly to the radiation polarization evolve from quasi-periodic ablative nanogrooves to regular lattices with sub-wavelength periods (90-400 nmyesRussian Academy of Science

Using a Laguerre-Gaussian beam to trap and cool the rotational motion of a mirror

We show theoretically that it is possible to trap and cool the rotational motion of a macroscopic mirror made of a perfectly reflecting spiral phase element using orbital angular momentum transfer from a Laguerre-Gaussian optical field. This technique offers a promising route to the placement of the rotor in its quantum mechanical ground state in the presence of thermal noise. It also opens up the possibility of simultaneously cooling a vibrational mode of the same mirror. Lastly, the proposed design may serve as a sensitive torsional balance in the quantum regime.Comment: New cavity design, reworked title; to appear in Phys. Rev. Let

The Formation of the Water Tourism Cluster in Saint-Petersburg: Analysis and Development Prospects

The purpose of the article is to consider the features and feasibility of the formation of a tourist water cluster in St. Petersburg, in particular, it is determined that the creation of clusters increases the tourist attractiveness of the region in the international arena, and also contributes to the development of domestic and inbound tourism, which is very important for the economy and the world status of our country.Methods. The main provisions for the formation of the main components of the tourism water cluster ofSt. Petersburg, the main role in this process is assigned to travel agencies, the dominant function of which is to provide basic tourist services for the placement, nutrition, transportation and entertainment of the consumer-tourist.Results. An algorithm for the formation of a water tourism cluster in St. Petersburg is proposed, which includes five stages: identification of the main competitive advantages of the city; allocation of places with existing tourist routes and designation them as General; identification of suitable components of the cluster structure in practice; allocation of the Protocol cluster; allocation of the dominant object in the Protocol cluster; work on ensuring uninterrupted interaction and cooperation of all components of the cluster; interaction with public authorities.Summary. For the development of the tourism industry of St. Petersburg it is necessary to organize modern forms of interaction of enterprises of different sizes and shapes with the state, the construction of a water tourism cluster, forms, components and provisions for the effective functioning of which are developed in the article

Sub-100 nanometer transverse gratings written by femtosecond laser pulses on a titanium surface

One-dimensional transverse (perpendicular to the laser polarization) gratings with periods Λ ≈ 50-60 nm were observed on a titanium surface within 150 nm wide, micrometer-long regular surface modification longitudinal stripes fabricated by multiple 744 nm Ti:sapphire femtosecond laser shots, occurring at a repetition rate of 10 HzyesBelgorod State Universit

Nikolai Klyuev’s Epistolary Review of Sergei Yesenin’s Poem ‘Pugachev’: “Dark Places” of Multidimensional Evaluation

This article presents a historical and literary analysis of the epistolary review by the peasant poet Nikolai Klyuev (1884—1937) of the dramatic poem ‘Pugachev’ (1922) by S. A. Yesenin. The review, contained in a letter dated January 28, 1922, has been characterized in literary studies as an “enthusiastic greeting.” However, the authors argue that Klyuev’s evaluation of Yesenin’s poem contains “dark places,” specifically his deliberate omission of the imagist poetics of ‘Pugachev’ and his seemingly unmotivated comparison of Yesenin’s dramatic poem with Pushkin’s tragedy ‘Boris Godunov’. The authors demonstrate that Klyuev believed that ‘Pugachev’, which reflects Yesenin’s rapid growth as a poet, was the result of his connection to the traditions of folk poetry rather than the product of the imagist school. Klyuev’s judgment that Yesenin’s poem was “more necessary and desirable than ‘Boris Godunov’” may appear illogical and paradoxical at first glance, but the authors emphasize that his epistolary review expresses only his personal relationship with the younger poet and does not evaluate the literary merits of the two works. The book ‘Pugachev’, which was sent to Vytegra along with the letter, became a sign of trust from the donor, a gift, a tangible expression of love and friendship from the addressee, and evidence of the spiritual and creative devotion of the student to his teacher. For Klyuev, who sought to restore his relationship with Yesenin, ‘Pugachev’ was “more necessary and desirable” because its content resonated with the idea of sacrificial service to his people, which is a recurring theme in Klyuev’s work

Assessment of quality and safety of pork treated with low-temperature atmospheric-pressure plasma

It is known that processing methods ensuring partial or full microbial inactivation are quite limited. Therefore, it is of great interest to develop technique and technologies allowing the effective action on microorganisms without a significant influence on product properties. The use of cold plasma can be one of the promising methods of meat product treatment by cold sterilization. The present work examines a possibility of chilled meat treatment with low-temperature atmospheric-pressure plasma to increase its stability to microbial spoilage and extend shelf life. To obtain low temperature plasma, the equipment developed by the designing department “Plasmamed” was used. Chilled meat was treated with low-temperature atmospheric-pressure argon plasma for 5, 10, 20 and 30 min. Samples were stored at a temperature of 2–4 °C for 10 days. Organoleptic indices, moisture weight fraction, changes in pH and water activity were analyzed before treatment and during storage. Sanitary microbiological analyses were carried out by the following indicators: quantity of mesophilic aerobic and facultative anaerobic microorganisms (QMAFAnM), the presence and quantity of coliforms, Salmonella, Escherichia coli, Listeria monocytogenes, Proteus. It was shown that meat cold treatment with argon plasma inhibited the development of mesophilic microorganisms. The colony forming units detected in the samples after ten days of storage were determined by the duration of exposure to plasma. It was proved that meat treatment for 15 and 30 min had the bactericidal effect and facilitated an improvement in meat color during storage. The organoleptic indices of the samples treated with plasma corresponded to the requirements of standards and approved consumer characteristics