149 research outputs found

    Broadband optical properties of monolayer and bulk MoS2

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    Layered semiconductors such as transition metal dichalcogenides (TMDs) offer endless possibilities for designing modern photonic and optoelectronic components. However, their optical engineering is still a challenging task owing to multiple obstacles, including the absence of a rapid, contactless, and the reliable method to obtain their dielectric function as well as to evaluate in situ the changes in optical constants and exciton binding energies. Here, we present an advanced approach based on ellipsometry measurements for retrieval of dielectric functions and the excitonic properties of both monolayer and bulk TMDs. Using this method, we conduct a detailed study of monolayer MoS2 and its bulk crystal in the broad spectral range (290–3300 nm). In the near- and mid-infrared ranges, both configurations appear to have no optical absorption and possess an extremely high dielectric permittivity making them favorable for lossless subwavelength photonics. In addition, the proposed approach opens a possibility to observe a previously unreported peak in the dielectric function of monolayer MoS2 induced by the use of perylene-3,4,9,10-tetracarboxylic acid tetrapotassium salt (PTAS) seeding promoters for MoS2 synthesis and thus enables its applications in chemical and biological sensing. Therefore, this technique as a whole offers a state-of-the-art metrological tool for next-generation TMD-based devices

    РЕЙТИНГ ИНВЕСТИЦИОННОГО ПОТЕНЦИАЛА РЕГИОНОВ РОССИЙСКОЙ ФЕДЕРАЦИИ: МНОГОМЕРНЫЙ СТАТИСТИЧЕСКИЙ АНАЛИЗ

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    Algorithm of the creation integral factor for estimation ofthe region’s investment potential is given in the article. It is founded on the main component method, using intwo stages. First at the rate of primary factors. Then at the rate of factors, that characterizing investmentpotential. Comparison given algorithm with method ofthe national rating agency «Expert RA» is presented.Приведен алгоритм построения интегрального показателядля оценки инвестиционногопотенциала региона. Оноснованнаметодеглавныхкомпонент, применяющийся в два этапа. Сначала на уровне первичныхпоказателей. Затемнауровнефакторов, характеризующих инвестиционный потенциал. Дано сравнение данной методики с методикой национальногорейтинговогоагентства«ЭкспертРА»

    Spark plasma sintering of SiC-based bulk materials from carbonaceous residue of rice husk thermal processing

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    Relevance. The search for a useful application of carbonaceous residues of rice husks thermal processing. These residues due to high silicon content in the inorganic part can potentially be used to produce silicon carbide – an important functional material for various fields of science and technology. Useful utilization of this waste will allow not only solving the environmental problem associated with their inefficient application and formal disposal, but also obtaining value-added products in the form of SiC-based ceramics. Aim. To obtain SiC-based bulk products from carbonaceous residues of rice husk thermal processing by spark plasma sintering with a minimum number of additional stages of feedstock processing. Objects. SiC-based bulk products obtained using carbonaceous residues of rice husk thermal processing. The samples were obtained by spark plasma sintering at 1800 °C, pressure of 60 MPa and holding time of 10 minutes. Methods. Spark plasma sintering; X-ray diffractometry (X-ray phase analysis); scanning electron microscopy; vacuumless arc discharge synthesis method. Results. The authors have carried out the experimental studies to assess the possibility of applying carbonaceous residue of rice husk thermal processing as a precursor for the synthesis of silicon carbide in bulk (ceramics) and dispersed (powder) forms. A series of experiments on spark plasma sintering of carbonaceous residue from rice husk thermal processing in the initial and milled form, with SiO2 silica sand additives, as well as with the use of silicon carbide powders synthesized from carbonaceous residue by vacuumless arc discharge method were implemented. The latter is performed within a one-stage fast-flowing process in an air environment and does not require the use of a vacuum system. Preliminary results demonstrated the possibility of obtaining bulk products and dispersed powders based on silicon carbide with a content of at least 50 and 60 wt %, respectively, and indicate the prospects of further increasing phase purity by optimizing spark plasma sintering and vacuumless arc discharge synthesis

    Hybrid Nanoparticles for Haloperidol Encapsulation: Quid Est Optimum?

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    The choice of drug delivery carrier is of paramount importance for the fate of a drug in a human body. In this study, we have prepared the hybrid nanoparticles composed of FDA-approved Eudragit L100-55 copolymer and polymeric surfactant Brij98 to load haloperidol-an antipsychotic hydrophobic drug used to treat schizophrenia and many other disorders. This platform shows good drug-loading efficiency and stability in comparison to the widely applied platforms of mesoporous silica (MSN) and a metal-organic framework (MOF). ZIF8, a biocompatible MOF, failed to encapsulate haloperidol, whereas MSN only showed limited encapsulation ability. Isothermal titration calorimetry showed that haloperidol has low binding with the surface of ZIF8 and MSN in comparison to Eudragit L100-55/Brij98, thus elucidating the striking difference in haloperidol loading. With further optimization, the haloperidol loading efficiency could reach up to 40% in the hybrid Eudragit L100-55/Brij98 nanoparticles with high stability over several months. Differential scanning calorimetry studies indicate that the encapsulated haloperidol stays in an amorphous state inside the Eudragit L100-55/Brij98 nanoparticles. Using a catalepsy and open field animal tests, we proved the prolongation of haloperidol release in vivo, resulting in later onset of action compared to the free drug

    Les droits disciplinaires des fonctions publiques : « unification », « harmonisation » ou « distanciation ». A propos de la loi du 26 avril 2016 relative à la déontologie et aux droits et obligations des fonctionnaires

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    The production of tt‾ , W+bb‾ and W+cc‾ is studied in the forward region of proton–proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98±0.02 fb−1 . The W bosons are reconstructed in the decays W→ℓν , where ℓ denotes muon or electron, while the b and c quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions.The production of ttt\overline{t}, W+bbW+b\overline{b} and W+ccW+c\overline{c} is studied in the forward region of proton-proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98 ±\pm 0.02 \mbox{fb}^{-1}. The WW bosons are reconstructed in the decays WνW\rightarrow\ell\nu, where \ell denotes muon or electron, while the bb and cc quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions

    Studies of beauty baryon decays to D0ph− and Λ+ch− final states

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    Measurement of the (eta c)(1S) production cross-section in proton-proton collisions via the decay (eta c)(1S) -> p(p)over-bar

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    The production of the ηc(1S)\eta_c (1S) state in proton-proton collisions is probed via its decay to the ppˉp \bar{p} final state with the LHCb detector, in the rapidity range 2.06.52.0 6.5 GeV/c. The cross-section for prompt production of ηc(1S)\eta_c (1S) mesons relative to the prompt J/ψJ/\psi cross-section is measured, for the first time, to be σηc(1S)/σJ/ψ=1.74±0.29±0.28±0.18B\sigma_{\eta_c (1S)}/\sigma_{J/\psi} = 1.74 \pm 0.29 \pm 0.28 \pm 0.18 _{B} at a centre-of-mass energy s=7\sqrt{s} = 7 TeV using data corresponding to an integrated luminosity of 0.7 fb1^{-1}, and σηc(1S)/σJ/ψ=1.60±0.29±0.25±0.17B\sigma_{\eta_c (1S)}/\sigma_{J/\psi} = 1.60 \pm 0.29 \pm 0.25 \pm 0.17 _{B} at s=8\sqrt{s} = 8 TeV using 2.0 fb1^{-1}. The uncertainties quoted are, in order, statistical, systematic, and that on the ratio of branching fractions of the ηc(1S)\eta_c (1S) and J/ψJ/\psi decays to the ppˉp \bar{p} final state. In addition, the inclusive branching fraction of bb-hadron decays into ηc(1S)\eta_c (1S) mesons is measured, for the first time, to be B(bηcX)=(4.88±0.64±0.25±0.67B)×103B ( b \rightarrow \eta_c X ) = (4.88 \pm 0.64 \pm 0.25 \pm 0.67 _{B}) \times 10^{-3}, where the third uncertainty includes also the uncertainty on the J/ψJ/\psi inclusive branching fraction from bb-hadron decays. The difference between the J/ψJ/\psi and ηc(1S)\eta_c (1S) meson masses is determined to be 114.7±1.5±0.1114.7 \pm 1.5 \pm 0.1 MeV/c2^2.The production of the ηc(1S)\eta _c (1S) state in proton-proton collisions is probed via its decay to the ppp\overline{p} final state with the LHCb detector, in the rapidity range 2.06.5GeV/c2.0 6.5 \mathrm{{\,GeV/}{ c}} . The cross-section for prompt production of ηc(1S)\eta _c (1S) mesons relative to the prompt J/ψ{{ J}}/{\psi } cross-section is measured, for the first time, to be σηc(1S)/σJ/ψ=1.74±0.29±0.28±0.18B\sigma _{\eta _c (1S)}/\sigma _{{{{ J}}/{\psi }}} = 1.74\, \pm \,0.29\, \pm \, 0.28\, \pm \,0.18 _{{\mathcal{B}}} at a centre-of-mass energy s=7 TeV{\sqrt{s}} = 7 {~\mathrm{TeV}} using data corresponding to an integrated luminosity of 0.7 fb1^{-1} , and σηc(1S)/σJ/ψ=1.60±0.29±0.25±0.17B\sigma _{\eta _c (1S)}/\sigma _{{{{ J}}/{\psi }}} = 1.60 \pm 0.29 \pm 0.25 \pm 0.17 _{{\mathcal{B}}} at s=8 TeV{\sqrt{s}} = 8 {~\mathrm{TeV}} using 2.0 fb1^{-1} . The uncertainties quoted are, in order, statistical, systematic, and that on the ratio of branching fractions of the ηc(1S)\eta _c (1S) and J/ψ{{ J}}/{\psi } decays to the ppp\overline{p} final state. In addition, the inclusive branching fraction of b{b} -hadron decays into ηc(1S)\eta _c (1S) mesons is measured, for the first time, to be B(bηcX)=(4.88±0.64±0.29±0.67B)×103{\mathcal{B}}( b {\rightarrow } \eta _c X ) = (4.88\, \pm \,0.64\, \pm \,0.29\, \pm \, 0.67 _{{\mathcal{B}}}) \times 10^{-3} , where the third uncertainty includes also the uncertainty on the J/ψ{{ J}}/{\psi } inclusive branching fraction from b{b} -hadron decays. The difference between the J/ψ{{ J}}/{\psi } and ηc(1S)\eta _c (1S) meson masses is determined to be 114.7±1.5±0.1MeV ⁣/c2114.7 \pm 1.5 \pm 0.1 {\mathrm {\,MeV\!/}c^2} .The production of the ηc(1S)\eta_c (1S) state in proton-proton collisions is probed via its decay to the ppˉp \bar{p} final state with the LHCb detector, in the rapidity range 2.06.52.0 6.5 GeV/c. The cross-section for prompt production of ηc(1S)\eta_c (1S) mesons relative to the prompt J/ψJ/\psi cross-section is measured, for the first time, to be σηc(1S)/σJ/ψ=1.74±0.29±0.28±0.18B\sigma_{\eta_c (1S)}/\sigma_{J/\psi} = 1.74 \pm 0.29 \pm 0.28 \pm 0.18 _{B} at a centre-of-mass energy s=7\sqrt{s} = 7 TeV using data corresponding to an integrated luminosity of 0.7 fb1^{-1}, and σηc(1S)/σJ/ψ=1.60±0.29±0.25±0.17B\sigma_{\eta_c (1S)}/\sigma_{J/\psi} = 1.60 \pm 0.29 \pm 0.25 \pm 0.17 _{B} at s=8\sqrt{s} = 8 TeV using 2.0 fb1^{-1}. The uncertainties quoted are, in order, statistical, systematic, and that on the ratio of branching fractions of the ηc(1S)\eta_c (1S) and J/ψJ/\psi decays to the ppˉp \bar{p} final state. In addition, the inclusive branching fraction of bb-hadron decays into ηc(1S)\eta_c (1S) mesons is measured, for the first time, to be B(bηcX)=(4.88±0.64±0.29±0.67B)×103B ( b \rightarrow \eta_c X ) = (4.88 \pm 0.64 \pm 0.29 \pm 0.67 _{B}) \times 10^{-3}, where the third uncertainty includes also the uncertainty on the J/ψJ/\psi inclusive branching fraction from bb-hadron decays. The difference between the J/ψJ/\psi and ηc(1S)\eta_c (1S) meson masses is determined to be 114.7±1.5±0.1114.7 \pm 1.5 \pm 0.1 MeV/c2^2
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