385 research outputs found
Synthesis of di(Imdazolium) and di(Pyrazolium) Salts as Precursors for N-heterocyclic Dicarbene Complexes
Alpha,omega-bis(pyrazol-1-yl)alkanes and alpha,omega-bis(imidazol-1-yl)alkanes with spacers consisting of four to ten methylene groups have been prepared from pyrazole, 3,5-dimethylpyrazole or imidazole and corresponding dibromoalkanes in a superbasic medium KOH-DMSO. The proposed method of synthesis allowed the preparation of new flexible bidentate ligands without the need to use toxic solvents and tedious workup procedures. Bis(pyrazol-1-yl)alkanes were further functionalized for their use as precursors for “non-classical” mesoionic N-heterocyclic carbene ligands. One the first step, iodine atoms were introduced to positions 4 of pyrazole rings by oxidative iodination using I[2]-HIO[3] system. On the next step, nitrogen atoms in positions 2 of pyrazole rings were alkylated using several agents. Reaction with methyliodide unexpectedly led to the formation of only mono-alkylated products even after 7 days of refluxing in a neat alkyliodide. Methylation by trimethyloxonium tetrafluoroborate or methyltriflate led to dimethylated products in high yields. Bis(imidazol-1-yl)alkanes were easily alkylated by methyliodide to give di(imidazolium) salts – precursors to “classic” N-heterocyclic dicarbenes
Elastic recoil detection studies of nearsurface hydrogen in cavity-grade Niobium‖,
Abstract Recent studies of the quality factor degradation mechanisms in superconducting RF niobium cavities at high surface magnetic fields revealed that RF performance may depend on the total hydrogen content in the 40 nm thick near-surface layer. Hydrogen distribution in niobium and its near-surface content variations after different chemical surface treatments has been addressed in previous studies. However, only chemical treatments were studied while heat treatments are equally important. In this work we use the elastic recoil detection (ERD) technique to systematically study the distribution of hydrogen in niobium sheet and cavity cutout samples subjected to chemical and heat treatments typically performed on niobium cavities. Our results indicate the near-surface segregation of hydrogen at the niobium oxide/niobium interface, and do not show any significant variation in hydrogen content after various heat and chemical treatments. We do not observe a direct correlation between total hydrogen content and the high field Q slope. Consequences of the observed hydrogen segregation are discussed in the framework of the NbH x phase diagram
Повседневный образ жизни рабочей молодежи в провинции
В статье представлены результаты качестенного исследования повседневного образа жизни молодых рабочих Ульяновска, проведенного в 2017 г. Подробно разбирается, как характер и режим работы структурируют повседневную жизнь молодых рабочих, определяют их досуг. Рассматриваются способы принятия и сопротивления задаваемому образу жизни, выбора альтернативных стратегий. В статье оспаривается взгляд на молодых рабочих как на социально уязвимую группу, утверждается, что морализаторское отношение к ней среди ученых мешает объективному анализу происходящих изменений. Главное из них заключается в переосмыслении ценности труда и рабочих профессий, в восприятии их не как окончательного жизненного выбора, а как пространства для самоопределения.
Благодарность. Авторы благодарят Российский фонд фундаментальных исследований, за счет средств которого подготовлена статья в рамках коллективного проекта «Повседневная культура рабочей молодежи в стратегиях жизни и занятости» (№17-03-00716-ОГН\18, рук. Е.Л. Омельченко). А также выражают признательность всей команде НИЦ «Регион» за собранный интересный эмпирический материал и конструктивные предложения по подготовке статьи
Kinematic instrumental analysis of the shoulder and elbow joint in normal conditions and with hypermobility of the joint in the gait cycle
Assess the functional state of the shoulder and elbow joints in normal conditions and with joint hypermobility syndrome (JHS) using the kinematic instrumental method of analyzing gai
Development of multisector pulsed neutron logging tool constructional parts
© 2016,International Journal of Pharmacy and Technology. All rights reserved.This paper focuses on the results of mathematical modeling aimed to construct multisector pulsed neutron logging (PNL) tool,which can be used to locate the cracks that are formed during hydraulic fracturing operations. This project resulted in a model of multisector PNL tool containing 6 detectors placed in such a way that they are equidistant from the source. This paper also presents:a. optimal collimation design providingdetection of neutronsfrom specific formations;b. model allowingto assess the quality of collimation in multisector logging tools; c. optimal detector configuration for the multisector PNL tool. The project results have also shown the possibility of increasing the number of registered thermal neutronsby introducing special constructional parts into the PNL tool design,allowing to changedirection of the neutron flux from the source into the area adjacent to detection units. Consequently,special constructional parts for the multisector PNL toolwere modeled to increase thenumber of neutrons recorded and determine the azimuth of the hydraulic fractures
Simulation of neutron transport for the purpose of neutron filters optimization in the pulsed neutron logging apparatus
© 2006-2015 Asian Research Publishing Network (ARPN). Numerical modeling of thermal neutron filters, which are an integral part of the apparatus of pulsed neutron logging (PNL), has been carried out. Many models of filters were created. The neutrons slowing down and absorption processes in filters was analyzed. Optimum structure and dimensions of neutron filters was offered
Improvement of personnel training for construction industry
Рынок образовательных услуг для строительной отрасли в настоящее время не успевает эффективно реагировать на потребности рынка специалистов и рабочих кадров для отрасли. В статье даны предложения для совершенствования подготовки кадров для строительства в высших учебных заведениях.Nowadays the market of the educational services for the construction industry cannot respond effectively to the needs of the market of professionals and skilled workers for the sector. The article contains suggestions for the improvement of the specialists training for the construction in higher education institutions. The adaptation of teaching by the modern requirements can be presented in three interconnected blocks: the organization of paid vocational training; the establishing of reference collection; graduates preparing for productive activities
Some mechanisms of inflammation development in type 2 diabetes mellitus
Inflammation plays a key role in the development and progression of type 2 diabetes (T2DM), a disease characterized by peripheral insulin resistance and systemic glucolipotoxicity. The main source of inflammation in the early stages of the disease is visceral adipose tissue (VT). Macrophages are innate immune cells that are present in all peripheral tissues, including VT. Violation of the response of VT (MT) macrophages to changes in the microenvironment underlies aberrant inflammation and the development of local and systemic insulin resistance. The inflammatory activation of macrophages is regulated at several levels: stimulation of cell surface receptors, intracellular signaling, transcription, and metabolic levels. Which are activated by the transformation of macrophages along the pro-inflammatory or anti-inflammatory pathways. Such polarization of macrophages in modern immunology is divided into classical anti-inflammatory M1 polarization and alternative anti-inflammatory M2 polarization of macrophages. The M1 / M2 ratio of macrophages in the process of inflammation ensures the resolution of inflammation at different stages of its development. The review considers the main mechanisms involved in VT inflammation and the development of insulin resistance in T2DM, supported with the participation of immunocompetent cells, M1 / M2, as well as growth factors and humoral immunity factors secreted during this process
Socio-Cultural Impact of Church Building in Russia (the Case of the Cathedral of Saint Martyr Catherine in Ekaterinburg)
In recent years, Russia has been going through a boom of church building. In 2009, the Russian Orthodox Church (ROC) had 29,263 parishes and by 2019 this figure had risen to 38,649. In the last decade, the growth in the number of Orthodox religious organizations and places of worship has by far exceeded that of other assets of social infrastructure. While the number of churches is growing, however, the number of schools, kindergartens and hospitals is steadily falling. Unlike other elements of social infrastructure, church building is funded not from the state budget but is financed by donors, sponsors and by the ROC itself, with some of the funds coming from payments for religious rites (baptism, weddings etc). This article analyzes the historical significance and socio-economic impact of church building by focusing on the case of the Cathedral of Saint Martyr Catherine in Ekaterinburg. The right choice of the construction site for the cathedral-the choice that would be agreeable to the metropolitan bishop, municipal government, businesses and sponsors, local community and opinion leaders-will ensure not only that the project will be duly completed but also underline the fact that local communities are able to establish consensus and recognize each other's interests in local decision-making. One of the possible locations considered for building St.Catherine's Cathedral in Ekaterinburg was a former industrial site in the centre of the city. Eventually, it was chosen as the most suitable place for this large-scale project. Redevelopment of an underused or abandoned industrial site, resulting in the improvement in the quality of urban environment, can be seen as an effective instrument of project realization, contributing to the building's social and economic significance. © Published under licence by IOP Publishing Ltd
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