Superconductivity, Electron Paramagnetic Resonance, and Raman Scattering Studies of Heterofullerides with Cs and Mg

In the present study, the results of investigation of physical properties of heterofullerides A3−xMxC60 (A=K, Rb, Cs, M=Be, Mg, Ca, Al, Fe, Tl, x=1,2); as well as RbCsTlC60, KCsTlC60, and KMg2C60 are described. All of the fullerides were synthesized by the exchange reactions of alkaline fullerides with anhydrous metal halides. Superconductivity was found in RbCsTlC60 and KCsTlC60

Characteristics of the secondary electrons calibration beam of the accelerator S-25R "Pakhra"

The characteristics of the secondary electrons` calibration quasi-monochromatic beam of the accelerator S-25R "Pakhra" of the Lebedev Physical Institute of the Russian Academy of Sciences (LPI) on the basis of magnet SP-57 are presented. With an electron energy in the range of 45-280 MeV, a collimator diameter in front of the trigger counters of 3 mm and copper Converter thicknesses of 1-3 mm, the energy resolution and beam intensity were 4.4-2.2% and around 16 e/sec, respectively

Hierarchically Porous Carbon Cloth–Polyaniline (CC–PANI) Composite Supercapacitor Electrodes with Enhanced Stability

In this work, hierarchically porous composites were prepared in the form of activated carbon cloth (CC) Busofit T–1–055 filled with an electrically conductive polymer, polyaniline (PANI), for use as pseudocapacitive electrodes of electrochemical supercapacitors (SCs). CC fibers have high nanoporosity and specific surface area, so it was possible to deposit (via the chemical oxidative polymerization of aniline) a significant amount of PANI on them in the form of a thin layer mainly located on the inner surface of the pores. Such morphology of the composite made allowed the combining of the high capacitive characteristics of PANI with the reversibility of electrochemical processes, high columbic efficiency and cyclic stability rather typical for carbon materials of double-layer SCs. The highest capacitance of composite electrodes of about 4.54 F/cm2 with high cyclic stability (no more than 8% of capacity loss after 2000 charge–discharge cycles with a current density of 10 A/cm2) and columbic efficiency (up to 98%) was achieved in 3 M H2SO4 electrolyte solution when PANI was synthesized from an aniline hydrochloride solution with a concentration of 0.25 M. Trasatti analysis revealed that 27% of specific capacitance corresponded to pseudocapacitance, and 73% to the double-layer capacitance

Азотсодержащие вещества в снеге районов падения ступеней ракеты-носителя «Протон» в 2009–2019 гг.

The article presents analysis of the snow pollution caused by flights of the Proton launch vehicles launched from the Baikonur cosmodrome in 2009–2019. Data on 1477 snow samples collected in areas in Central Kazakhstan, south­east of Western Siberia, and north­east of the Altai are summarized to assess the pollution. In the uninhabited areas in Central Kazakhstan, where rocket fuel is spilled, pollution of snow was detected at 18 fall sites at a distance of up to 10 m from the fragments of the stages. The background value of pH is estimated as 6.6±0.9. The following nitrogen-­containing compounds (mg/l) were found in snow taken in the unpolluted territories of Central Kazakhstan: NO3­ (2.3±3.4), NH4+ (0.75±0.98) and to a lesser extent NO2– (0.015±0.019); asymmetric dimethylhydrazine and nitrosodimethylamine were not detected. The chemical composition of snow in the fall areas of the second stage of the Proton launch vehicle is in a good agreement with the background level of nitrogen­-containing substances of natural origin. There were no traces of the rocket fuel. Thus, in the snow on the Ketsko­Tym plain (south­east of Western Siberia) and north­east of Altai, the background content of nitrogen-­containing substances is equal, respectively (mg/l): NO3– (0.36±0.28 and 0.47±0.59); NH4+ (< 0.05 and 0.20±0.27); NO2– (0.048±0.016 and 0.027±0.073), which is determined by regional features and distance from sources of nitrogen­-containing substances. The data obtained allow us to conclude that the areas of the rocket falls on the above territories are not an environmental hazard to the environment by the concentration of nitrogen-­containing substances in the snow.Обобщены данные по 1477 пробам снега из районов падения ступеней ракеты-носителя «Протон» в Центральном Казахстане, на юго-востоке Западной Сибири и северо-востоке Алтая. В безлюдных территориях Центрального Казахстана, куда попадает ракетное топливо, достоверное загрязнение снега установлено на расстоянии не более 10 м от фрагментов падения первой ступени. Химический состав снега районов падения второй ступени (юго-восток Западной Сибири и северо-восток Алтая) отражает фоновые уровни азотсодержащих соединений природного происхождения и показывает отсутствие компонентов ракетного топлива. Очевидно, что районы падения и первой, и второй ступеней ракет-носителей «Протон», запускаемых с космодрома Байконур, не представляют собой зоны экологического бедствия

Обеспечение качества поверхностного слоя изделий с гетерогенными покрытиями при механической обработке

It is shown that when machining products from materials with heterogeneous structure, possibilities of management of a condition of a blanket are significantly limited. As an example of management, cutting processing of products from materials with heterogeneous structure – turning of high-strength flame evaporated coverings is considered. Because for an amorphous component of heterogeneous coverings the lack of deformation hardening is peculiar considerable deformation of the cut-off material is observed at their processing and characteristic shaving is formed. Highintensity thermobaric impact on the processed heterogeneous material leads to partial crystallization in a thin blanket with the high content of an amorphous phase. As a result of researches the criterion which quantitatively estimates the statistics, which complexly characterize uniformity of structure of materials and dispersion of their properties, is offered. The criterion allows defining ability of materials to be exposed to cutting without carrying out long experiments.Показано, что при механической обработке изделий из материалов с гетерогенной структурой возможности управления состоянием поверхностного слоя существенно ограничиваются. В качестве примера управления рассмотрена лезвийная обработка изделий из материалов с гетерогенной структурой – точение высокопрочных покрытий, нанесенных газопламенным напылением. В связи с тем что для аморфной составляющей гетерогенных покрытий свойственно отсутствие деформационного упрочнения, при их обработке наблюдается значительная деформация срезаемого материала и образуется характерная стружка. Высокоинтенсивное термобарическое воздействие на обрабатываемый гетерогенный материал приводит к частичной кристаллизации в тонком поверхностном слое с высоким содержанием аморфной фазы. Предложен критерий, количественно оценивающий статистические показатели, которые комплексно характеризуют однородность структуры материалов, разброс их свойств по величине. Критерий позволяет определить способность материалов подвергаться резанию без проведения длительных экспериментов

Creation of the precision magnetic spectrometer SCAN-3

The new JINR project [1] is aimed at studies of highly excited nuclear matter created in nuclei by a high-energy deuteron beam. The matter is studied through observation of its particular decay products - pairs of energetic particles with a wide opening angle, close to 180°. The new precision hybrid magnetic spectrometer SCAN-3 is to be built for detecting charged (π±, K±, p) and neutral (n) particles produced at the JINR Nuclotron internal target in dA collisions. One of the main and complex tasks is a study of low-energy ηA interaction and a search for η-bound states (η-mesic nuclei). Basic elements of the spectrometer and its characteristics are discussed in the article