Determination of area-to-mass ratio of geosynchronous objects using positional observations obtained at Terskol pike

Представлены результаты совместного определения элементов орбит и параметра парусности объекта γ = A/m для группы геосинхронных фрагментов космического мусора на основании позиционных наблюдений, полученных на уникальной научной установке «Цейсс-2000» на Терскольской обсерватории Института астрономии РАН в период 11—25 сентября 2020 г.The results of the joint determination of the orbital elements and the area-to-mass ratio of the object γ = A/m for a group of geosynchronous fragments of space debris based on positional observations obtained at the unique scientific installation Zeiss-2000 at the Terskol Observatory of the Institute of Astronomy of the Russian Academy of Sciences during September 11—25, 2020 are presented.Работа выполнена в рамках государственного задания Министерства науки и высшего образования Российской Федерации (тема № 0721-2020-0049)

Trimethylsilylethynyl-Substituted Pyrene Doped Materials as Improved Fluorescent Sensors towards Nitroaromatic Explosives and Related Compounds

The well-known fluorophore, namely 1,3,6,8-tetrakis[(trimethylsilyl)ethynyl]pyrene, has been studied profoundly as a fluorescent sensor toward nitroaromatic compounds in solutions and vapor phase. Three prototypes of fluorescent materials for vapor sensing were prepared via electrospinning and drop-casting onto the melamine formaldehyde foam with the fluorophore as a pure solid or as a dopant in the polystyrene matrix. It has been shown that this fluorophore and solid fluorescent materials based on it have high detection limits toward nitroaromatic compounds within the range of 10−8 to 10−9 M in acetonitrile solution and within the up to ppb range in the vapor phase. The model, expanding on Frisch’s permeation model, was utilized to characterize the fluorescence response of materials relative to vapor concentration and duration of exposure to vapor. All prototypes can be used as sensor materials exhibiting a good sensitivity and selectivity for the original hand-made sniffer for detecting nitro-containing explosives in the vapor phase for real-time application. © 2023 by the authors.Russian Foundation for Basic Research, РФФИ: 20-37-90108; Ministry of Education and Science of the Russian Federation, Minobrnauka: AAAA-A19-119011790132-7The reported study was funded by RFBR, project number 20-37-90108. The synthetic part of this work was supported by the Ministry of Science and Higher Education of the Russian Federation within the framework of the State Assignment for Research (Project No. AAAA-A19-119011790132-7)

Global Stratotype Section and Point (GSSP) for the base-Artinskian Stage (Lower Permian)

The base-Artinskian Stage GSSP is defined at 0.6 m above the base of bed 4b at the Dal’ny Tulkas section in the southern Urals of Russia (53.88847N and 056.51615E). This point corresponds to the First Appearance Datum of the conodont Sweetognathus asymmetricus, which is part of a well-defined and widely distributed lineage. Additional markers for correlation include a radioisotopic age interpolated between 290.1 and 290.5 Ma, a strontium isotopic ratio of .70767, and many additional fossils groups, particularly ammonoids and fusulines, but also including small foraminiferans, radiolarians, and palynomorphs. Finally, the boundary occurs within a transgressive succession, near, or at a maximum flooding surface in many sections, thereby forming a distinctive sequence stratigraphic signature in the field. The Artinskian Stage is the third stage of the Lower Permian or Cisuralian Series

New V-shaped 2,4-di(hetero)arylpyrimidine push-pull systems: Synthesis, solvatochromism and sensitivity towards nitroaromatic compounds

Novel D–π–A–π–D type pyrimidine-based dyes, possessing (hetero)aryl electron-donating groups in 2,4-positions were synthesized, and their photophysical properties were investigated by using absorption and emission spectral analyses. All dyes proved to exhibit a strong emission solvatochromism with quantum yields up to 0.96, depending on their molecular structure and solvent polarity. The compounds have been established to undergo a reversible protonation, directed at nitrogen atoms of the pyrimidine ring, and these phenomena are associated with dramatic color changes. In addition, fluorophores 5a-d show a high sensitive response for nitroaromatic traces in solutions or real-time detection of their vapors in air. These findings indicate that the compounds obtained can be regarded as excellent fluorophores for fluorescent material applications. © 2018 Elsevier LtdRussian Foundation for Basic Research, RFBR: 17-03-00011-AMinistry of Education and Science of the Russian Federation, Minobrnauka: 4.6759.2017/BCThis work (synthetic part and sensory properties) was supported by the Russian Foundation for Basic Research (Research Project No. 17-03-00011-A ). N.I. Makarova, E.V.V. and A.V.M. would like to acknowledge financial support for the absorption and fluorescence studies from the Ministry of Education and Science of the Russian Federation within the framework of the State Assignment for Research (project No. 4.6759.2017/BC ). The authors are grateful to Mr. Grigory A. Kim for carrying out the DFT calculations which were performed by using « Uran » supercomputer of the Institute of mathematic and mechanics of the Ural Brach of the Russian Academy of Sciences. NMR experiments were carried out by using equipment of the Center for Joint Use “Spectroscopy and Analysis of Organic Compounds” at the Postovsky Institute of Organic Synthesis of the Ural Branch of the Russian Academy of Sciences. VNC is grateful to the Ural Branch of the Russian Academy of Sciences (project № 0398-2018-0054 )

Devonian organogenic buildings of the Urals and adjacent regions of East-Europian Platform and West Siberian

Several reef-building systems occurred during Cambrian-Devonian on the Urals and adjacent regions of the East-European Platform. The first phase was manifested in the Lower Cambrian within a limited area of the western slope of the Urals. The next stage occured on the western slope of Urals during Early to Middle Devonian as a result of Caledonian orogeny. This reef complex is traced on the western slope of the Urals from the Ural River latitude on the south to Barents Sea on the north. Late Devonian bioherms on the territory of the East-European Platform are distributed over a wide area from the Western Urals to the Volga basin. On the east slope of the Urals and in West Siberia bioherms are attributed to marginal structures of depressions