112 research outputs found

    High-Energy and High-Power-Density Potassium Ion Batteries Using Dihydrophenazine-Based Polymer as Active Cathode Material

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    Polymeric aromatic amines were shown to be very promising cathodes for lithium-ion batteries. Surprisingly, these materials are scarcely used for designing post-lithium batteries. In this Letter, we investigate the application of the high-voltage poly(N-phenyl-5,10-dihydrophenazine) (p-DPPZ) cathodes for K-ion batteries. The designed batteries demonstrate an impressive specific capacity of 162 mAh g-1 at the current density of 200 mA g-1, operate efficiently at high current densities of 2-10 A g-1, enabling charge and discharge within ∼1-4 min, and deliver the specific capacity of 125-145 mAh g-1 with a retention of 96 and 79% after 100 and 1000 charge-discharge cycles, respectively. Finally, these K-ion batteries with polymeric p-DPPZ cathodes showed rather outstanding specific power of >3 × 104 W kg-1, thus paving a way to the design of ultrafast and durable high-capacity metal-ion batteries matching the increasing demand for high power and high energy density electrochemical energy storage devices. © 2019 American Chemical Society.Government Council on Grants, Russian Federation: 02.Russian Science Foundation, RSF: 16-13-00111This work was supported by Russian Science Foundation, project 16-13-00111. We acknowledge the support of Dr. A. Mumyatov with FTIR spectroscopy measurements. The XPS measurements were supported by the Government of Russian Federation (Act 211, Agreement No. 02.A03.21.0006) and Theme “Electron” (no. AAAA-A18-118020190098-5)

    On the design of experiments to study extreme field limits

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    We propose experiments on the collision of high intensity electromagnetic pulses with electron bunches and on the collision of multiple electromagnetic pulses for studying extreme field limits in the nonlinear interaction of electromagnetic waves. The effects of nonlinear QED will be revealed in these laser plasma experiments.Comment: 7 pages, 3 figures, 1 table; 15th Advanced Accelerator Concepts Workshop (AAC 2012), Austin, Texas, 10-15 June, 201

    Nonlinear Coherent Modes of Trapped Bose-Einstein Condensates

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    Nonlinear coherent modes are the collective states of trapped Bose atoms, corresponding to different energy levels. These modes can be created starting from the ground state condensate that can be excited by means of a resonant alternating field. A thorough theory for the resonant excitation of the coherent modes is presented. The necessary and sufficient conditions for the feasibility of this process are found. Temporal behaviour of fractional populations and of relative phases exhibits dynamic critical phenomena on a critical line of the parametric manifold. The origin of these critical phenomena is elucidated by analyzing the structure of the phase space. An atomic cloud, containing the coherent modes, possesses several interesting features, such as interference patterns, interference current, spin squeezing, and massive entanglement. The developed theory suggests a generalization of resonant effects in optics to nonlinear systems of Bose-condensed atoms.Comment: 26 pages, Revtex, no figure

    Resonant Generation of Topological Modes in Trapped Bose Gases

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    Trapped Bose atoms cooled down to temperatures below the Bose-Einstein condensation temperature are considered. Stationary solutions to the Gross-Pitaevskii equation (GPE) define the topological coherent modes, representing nonground-state Bose-Einstein condensates. These modes can be generated by means of alternating fields whose frequencies are in resonance with the transition frequencies between two collective energy levels corresponding to two different topological modes. The theory of resonant generation of these modes is generalized in several aspects: Multiple-mode formation is described; a shape-conservation criterion is derived, imposing restrictions on the admissible spatial dependence of resonant fields; evolution equations for the case of three coherent modes are investigated; the complete stability analysis is accomplished; the effects of harmonic generation and parametric conversion for the topological coherent modes are predicted. All considerations are realized both by employing approximate analytical methods as well as by numerically solving the GPE. Numerical solutions confirm all conclusions following from analytical methods.Comment: One reference modifie

    THE RUSSIAN DATA OF INTERNATIONAL ENDORSE REGISTER (EPIDEMIOLOGIC INTERNATIONAL DAY FOR THE EVALUATION OF PATIENTS AT RISK OF VENOUS THROMBOSIS IN ACUTE HOSPITAL CARE SETTING)

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    Aim. To estimate a risk factor frequency of venous thromboembolism (VTE) in patients urgently hospitalized in hospitals, and also to estimate of patients part having effective prevention of VTE.Material and methods. ENDORSE (Epidemiologic International Day for the Evaluation of Patients at Risk of Venous Thrombosis in Acute Hospital Care Setting) is the international register. Patients of 40 years and older hospitalised in therapeutic departments as well as patients of 18 years and older hospitalised in surgical departments (358 hospitals in 32 countries) were included in the register. The case history analysis of all patients was performed for estimation of risk VTE and evaluation of preventive therapy quality according to American College of Chest Physicians (ACCP) Recommendation 2004.Results. Totally 68 183 patients (including 30 827 (45%) surgical patients and 37 356 (55%) therapeutic patients) were enrolled in Global ENDORSE Register. Russian centers enrolled 4 788 patients (including 2 829 (59%) surgical patients and 1 959 (41%) therapeutic patients). Totally 35 329 (51,8%) patients enrolled in Global ENDORSE Register (64,4% of surgical patients (19 842) and 41,5% of therapeutic patients (15 487)) had VTE risks. In Russia 2 188 enrolled patients (45,7%) had VTE risks (52% of surgical patients (1 470) and 36,7% of therapeutic patients (718). Totally 17 732 (50,2%) patients enrolled in Global Register ENDORSE and having VTE risks received VTE preventive therapy according to АССР Recommendations 2004. In Russia 521 (23,8%) patients enrolled in Global ENDORSE Register and having VTE risks received VTE preventive therapy according to АССР Recommendations 2004. It is more than 2 times less in comparison with world level (р<0.001).Conclusion. There are a lot of patients with VTE risks in hospitals. It is necessary to improve preventive therapy of VTE due to better hospital management and more active use of АССР Recommendations 2004

    Octahydroxytetraazapentacenedione: New Organic Electrode Material for Fast and Stable Potassium Batteries

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    We report the synthesis and electrochemical characterization of octahydroxytetraazapentacenedione (OHTAPQ). The potassium batteries using OHTAPQ as electrode material delivered the specific capacity of 190 mAh g−1 at the current density of 0.6 A g−1. The use of the concentrated (2.2 M KPF6) diglyme-based electrolyte suppressed significantly the capacity fading of the potassium half-cells with OHTAPQ electrodes thus enabling their stable operation for 1200 charge-discharge cycles. Furthermore, OHTAPQ delivered the specific discharge capacity of 82–103 mAh g−1 at high current densities of 9–21 A g−1, which leads to high power densities approaching 41000 W kg−1. Thus, we demonstrate that the rationally designed organic electrode material enables high-capacity and high-power potassium batteries, which can be considered as a more environment-friendly and scalable alternative to the mainstream lithium-ion battery technology. © 2021 Elsevier B.V.This work was supported by the Russian Ministry of Science and Education (project 0089-2019-0010/AAAA-A19-119071190044-3 ). The XPS measurements were supported by the Ministry of Science and Higher Education of the Russian Federation (FEUZ-2020-0060), and Theme “Electron”, AAAA-A18-118020190098-5 at IPT UrFU and IMP UB RAS . The solid-state NMR spectroscopy experiments were performed at the Center of the Shared Facilities of IPCP RAS and Research Resource Center of the Scientific Center “Chernogolovka” of RAS. PAT acknowledges the support from EU’s Horizon 2020 ERA-Chair project ExCEED, grant agreement No 952008

    Exotic dense-matter states pumped by a relativistic laser plasma in the radiation-dominated regime

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    In high-spectral resolution experiments with the petawatt Vulcan laser, strong x-ray radiation of KK hollow atoms (atoms without n = 1 electrons) from thin Al foils was observed at pulse intensities of 3 x 10(20) W/cm(2). The observations of spectra from these exotic states of matter are supported by detailed kinetics calculations, and are consistent with a picture in which an intense polychromatic x-ray field, formed from Thomson scattering and bremsstrahlung in the electrostatic fields at the target surface, drives the KK hollow atom production. We estimate that this x-ray field has an intensity of >5 x 10(18) W/cm(2) and is in the 3 keV range

    Observation of narrow baryon resonance decaying into pKs0pK^0_s in pA-interactions at 70GeV/c70 GeV/c with SVD-2 setup

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    SVD-2 experiment data have been analyzed to search for an exotic baryon state, the Θ+\Theta^+-baryon, in a pKs0pK^0_s decay mode at 70GeV/c70 GeV/c on IHEP accelerator. The reaction pApKs0+XpA \to pK^0_s+X with a limited multiplicity was used in the analysis. The pKs0pK^0_s invariant mass spectrum shows a resonant structure with M=1526±3(stat.)±3(syst.)MeV/c2M=1526\pm3(stat.)\pm 3(syst.) MeV/c^2 and Γ<24MeV/c2\Gamma < 24 MeV/c^2. The statistical significance of this peak was estimated to be of 5.6σ5.6 \sigma. The mass and width of the resonance is compatible with the recently reported Θ+\Theta^+- baryon with positive strangeness which was predicted as an exotic pentaquark (uuddsˉuudd\bar{s}) baryon state. The total cross section for Θ+\Theta^+ production in pN-interactions for XF0X_F\ge 0 was estimated to be (30÷120)μb(30\div120) \mu b and no essential deviation from A-dependence for inelastic events (A0.7)(\sim A^{0.7}) was found.Comment: 8 pages, 7 figures, To be submitted to Yadernaya Fizika. v3-v5 - Some references added, minor typos correcte

    X-ray spectroscopy of super-intense laser-produced plasmas for the study of nonlinear processes. Comparison with PIC simulations

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    We present X-ray spectroscopic diagnostics in femto-second laser-driven experiments revealing nonlinear phenomena caused by the strong coupling of the laser radiation with the created plasma. Among those nonlinear phenomena, we found the signatures of the Two Plasmon Decay (TPD) instability in a laser-driven CO2 cluster-based plasma by analyzing the Langmuir dips in the profile of the O VIII Lyϵ line, caused by the Langmuir waves created at the high laser intensity 3 1018Wcm-2. With similar laser intensities, we reveal also the nonlinear phenomenon of the Second Harmonic Generation (SHG) of the laser frequency by analyzing the nonlinear phenomenon of satellites of Lyman δ and ϵ lines of Ar XVII. In the case of relativistic laser-plasma interaction we discovered the Parametric Decay Instability (PDI)-induced ion acoustic turbulence produced simultaneously with Langmuir waves via irradiation of thin Si foils by laser intensities of 1021Wcm-2
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