1,223 research outputs found
Optical Diagnostics For The Study Of Plasma Evolution In Linear Theta-pinch Tc-1
No full textThe plasma generated in the field reversed theta-pinch TC-1 discharge was investigated by means of a number of optical diagnostics: CO2 laser-based interferometry, visible-VUV spectroscopy and ruby laser Thomson scattering. The evolution of the local electron density was studied by CO2 laser intereferometry. Thomson scattering was employed for measurements of the electron density and temperature with high spatial resolution. The temporal behavior of line emission of oxygen and carbon in various ionization stages was studied by VUV spectroscopy. The time dependence of the electron temperature was evaluated from the analysis of the time history of line emission of impurity ions. The ion temperature was measured from the Doppler-broadened oxygen line emission profiles.264747754Aramaki, E.A., Porto, P., Berni, L., Honda, R.Y., Ueda, M., Doi, I., Machida, M., (1989) Nucl. Instr. Meth. Phys. Res., A, 280, p. 597Tuszewski, M., (1988) Nuclear Fusion, 28, p. 2033Campos, D.O., Machida, M., Berni, L.A., Kantor, M.Yu., Moshkalyov, S.A., Lebedev, S.V., (1995) Proc. de 30 Encontro Bras. de Física dos Plasmas, p. 90. , Águas de Lindóia, SP, BrasilBerni, L.A., Campos, D.O., Machida, M., Moshkalyov, S.A., Lebedev, S.V., Monteiro, M.J.R., Zibordi, R., (1995) Proc. de 30 Encontro Bras. de Física dos Plasmas, p. 79. , Águas de Lindóia, SP, BrasilMoshkalyov, S.A., Machida, M., Lebedev, S.V., Campos, D.O., (1995) Revista Bras. de Física Appl. Instr., 10, p. 107Greve, P., Kato, M., Kunze, H.-J., Hornady, R.S., (1981) Phys.Rev., A, 24, p. 429Kunze, H.-J., (1971) Phys.Rev., A, 3, p. 93
Low-angle Thomson Scattering Experiment For Determination Of Plasma Electron Density And Temperature
No full textIn this work we show results of measurements of the electron density ne and temperature Te by using small-angle Thomson scattering in a theta-pinch plasma. The method of measurement and analysis developed here is based on integration of only two ranges of the scattering profile. This method simplifies the experimental set up, because it needs only two detectors for simultaneous determination of ne and Te, instead of the commonly 5-7 detectors used in 90° experiments. The results obtained for low-angle scattering are compared with the measurements at 90° using single pass and multipass under the same plasma conditions.25601/02/15437441Berni, L.A., Campos, D.O., Machida, M., Moshkalyov, S.A., Lebedev, S.V., Molecular Rayleigh scattering as calibration method for Thomson scattering experiments (1996) Brazilian Journal of Physics, 26 (4), p. 755Campos, D.O., Machida, M., Berni, L.A., Moshkalyov, S.A., Lebedev, S.V., The feasibility study of a low-angle Thomson scattering for determination of plasma electron density and temperature (1995) 3o, Encontro Brasileiro de Física dos Plasmas - Fifth Brazilian Plasma Astrophysics Workshop, , Águas de Lindóida, SP, 4-6 December 1995Campos, D.O., Machida, M., Berni, L.A., Kantor, M., Moshkalyov, S.A., Lebedev, S.V., Experimental study of conventional and multipass Thomson scattering diagnostics (1996) Japanese Journal of Applied Physics, 35 (12 A), p. 6273Campos, D.O., Machida, M., Berni, L.A., Kantor, M., Moshkalyov, S.A., Lebedev, S.V., The application of a multipass system for Thomson scattering diagnostics in magnetically confined plasmas (1996) Brazilian Journal of Physics, 26 (4), p. 742Sheffield, J., (1975) Plasma Scattering of Electromagnetic Radiation, , Academic Press, New Yor
Measurement of the time-dependent CP asymmetry in B0 -> J/ψ KS0 decays
No full textThis Letter reports a measurement of the CP violation observables SJ/ψK0S and CJ/ψK0S in the decay channel B0→J/ψK0S performed with 1.0 fb−1 of pp collisions at s√=7 TeV collected by the LHCb experiment. The fit to the data yields SJ/ψK0S=0.73±0.07(stat)±0.04(syst) and CJ/ψK0S=0.03±0.09(stat)±0.01(syst). Both values are consistent with the current world averages and within
expectations from the Standard Model
Correction: Strokova et al. Interaction Mechanisms in «Portland Cement—Functional Polymer Mineral Additives» Binder Produced by Different Methods. Materials 2025, 18, 3178
No full textMikhail Lebedev was not included as an author in the original publication [...
First observation of Bs → J/ψf0(980) decays
No full textUsing data collected with the LHCb detector in proton–proton collisions at a centre-of-mass energy of 7 TeV, the hadronic decay is observed. This CP eigenstate mode could be used to measure mixing-induced CP violation in the system. Using a fit to the π+π− mass spectrum with interfering resonances gives . In the interval ±90 MeV around 980 MeV, corresponding to approximately two full f0 widths we also find , where in both cases the uncertainties are statistical and systematic, respectively
Author Correction: Local Josephson vortex generation and manipulation with a Magnetic Force Microscope (Nature Communications, (2019), 10, 1, (4009), 10.1038/s41467-019-11924-0)
No full text© 2019, The Author(s). The original version of this Article contained an error in the spelling of the author Christophe Brun, which was incorrectly given as Chritophe Brun. Additionally this Article omitted from the author list the seventh author Nickolay Lebedev, who is from the ‘Moscow Institute of Physics and Technology, 141700 Dolgoprudny, Russia’. These errors have now been corrected in both the PDF and HTML versions of the Article
An experimental investigation of the azimuthal structures formed during the ablation phase of wire array z-pinches
No full textA series of wire array implosion experiments have been carried out on MAGPIE, a 1.4MA peak current, 240ns
rise-time pulsed power generator located at Imperial College London. The aim of these experiments was to investigate
the azimuthal structure of ablation plasma produced during the early stages of wire array implosions. Previous
work [Lebedev, S.V., et al., PoP, 2001] has demonstrated that a significant portion of the implosion time is
dominated by the ablation phase, during which the dense wire cores remain at their initial radius and ablate
streams of plasma towards the array axis. This ablation plasma prefills the array, and its distribution forms the
initial conditions for the eventual snowplough-like implosion.
In order to carry out this investigation a new two-colour end-on interferometry system was constructed. A custom
software suite was developed in order to analyse the resulting data, enabling the conversion of the raw interferograms
into 2D electron density maps.
The experiments focused on cylindrical tungsten and aluminium arrays of between 8 and 128 wires. The structures
observed in aluminium arrays were dominated by collisional features. Networks of oblique shocks were
formed as the ablation streams interacted with their neighbours. Analysis of these shock structures allowed an
estimate to be made for the Mach number of the ablation streams, M=7.9-8.2. In contrast, the structures observed
in the tungsten experiments were characterised by smooth density profiles, consistent with relatively long
ion mean free paths. The quantitative nature of the dataset makes it ideal for comparison with the results of numerical
simulations.
Also reported in this thesis is the development of two CW laser diagnostics, a quadrature interferometer, and a
Faraday current diagnostic. The design of these diagnostics is discussed and some examples of the analysis are
presented
Measurement of the D+/- production asymmetry in 7 TeV pp collisions
No full textThe asymmetry in the production cross-section \sigma of D+/- mesons, A_P = (\sigma(D+) - \sigma(D-))/(\sigma(D+) + \sigma(D-)), is measured in bins of pseudorapidity \eta and transverse momentum p_T within the acceptance of the LHCb detector. The result is obtained with a sample of D+ -> K_S pi+ decays corresponding to an integrated luminosity of 1.0 fb^-1, collected in pp collisions at a centre of mass energy of 7 TeV at the Large Hadron Collider. When integrated over the kinematic range 2.0 K_S pi+ decay is negligible. No significant dependence on \eta or p_T is observed
Anna Colin Lebedev, Le cœur politique des mères, Analyse du mouvement des mères de soldats en Russie
No full textIn this valuable piece of sociological research Anna Colin Lebedev scrutinizes the modus operandi of a non‑governmental organisation of women activists taking on the essentially male domain of the military authorities in post‑Soviet Russia. With no dearth of academic studies stressing the lack of effective action from below in modern Russia, the author deems the Union of Committees of Soldiers’ Mothers of Russia atypical, based on its assistance for over twenty years to individual families wh..
Analysis of methods for calculating spur gear for deep contact strength
No full textSpur gear is an integral part of transport and technological machines structure. To increase the load ability of the spur gear, chemical heat treatment of the working cogs surfaces is used. Spur gear with chemical heat treatment must be checked for deep contact strength. The article analyzes various methods (according to GOST 21354-87, methods using the generalized criterion of the limit state for structurally inhomogeneous material by Lebedev-Pisarenko, methods from the handbook describing reducers of power machines etc.) for calculating spur and helical gearing for deep contact strength. The author presents all necessary formulas and graphs for the implementation of each methods, and compares the calculations results of these methods with the results of experimental studies of cemented cylindrical rollers for deep contact destruction
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