375 research outputs found

    Deterministic spatio-temporal control of nano-optical fields in optical antennas and nano transmission lines

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    We show that pulse shaping techniques can be applied to tailor the ultrafast temporal response of the strongly confined and enhanced optical near fields in the feed gap of resonant optical antennas (ROAs). Using finite-difference time-domain (FDTD) simulations followed by Fourier transformation, we obtain the impulse response of a nano structure in the frequency domain, which allows obtaining its temporal response to any arbitrary pulse shape. We apply the method to achieve deterministic optimal temporal field compression in ROAs with reduced symmetry and in a two-wire transmission line connected to a symmetric dipole antenna. The method described here will be of importance for experiments involving coherent control of field propagation in nanophotonic structures and of light-induced processes in nanometer scale volumes.Comment: 5 pages, 5 figure

    Реконструкция Гусиноозерской ГРЭС

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    Выпускная квалификационная работа содержит 95 страниц, 39 рисунков, 34 таблицы, 6 источников литературы и всего 4 приложения. Ключевые слова: электрическая станция, элегазовый выключатель, турбогенератор, короткое замыкание, асинхронный режим, «Mustang».The Degree Work contains 95 pages, 39 pictures, 34 tables sheets, 6 information sourses and 4 application. Key words: power station, generator, short curcuit, Mustang, Sulfur hexafluoride switche

    Measurement of hadronic shower punchthrough in magnetic field

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    The total punchthrough probability of showers produced by negative pions, positive pions, positive kaons and protons, has been measured as a function of depth in an absorber in a magnetic field ranging from 0 to 3 Tesla. The incident particle momentum varied from 10 to 300 GeV/c. The lateral shower development and particle multiplicity at several absorber depths have been determined. The measurements are compared with the predictions of Monte Carlo simulation programs

    Status report of the RD5 experiment

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    Single and multi-photon events with missing energy in e+ee^+ e^- collisions at 161 GeV < s\sqrt{s} < 172 GeV

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    A search for single and multi-photon events with missing energy is performed using data collected at centre-of-mass energies between 161 GeV and 172 GeV for a total of 20.9 pb1^{-1} of integrated luminosity. The results obtained are used to derive the value for the ννˉγ(γ)\nu\bar{\nu}\gamma(\gamma) cross section as well as upper limits on new physics processes

    Внедрение и принцип работы системы сейсмического мониторинга горного массива для работы в условиях ООО "Шахта "Усковская"

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    The status of the Silicon Microvertex Detector (SMD) and its installation into the LEP-L3 experiment are presented, highlighting novel features and sophisticated techniques. Preliminary results based on 1993 data are given and compared with Monte Carlo predictions, to understand the detector performances and its tracking capabilities

    Study of the Weak Charged Hadronic Current in b Decays

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    Charged and neutral particle multiplicities of jets associated with identified semileptonic and hadronic b decays are studied. The observed differences between these jets are used to determine the inclusive properties of the weak charged hadronic current. The average charged particle multiplicity of the weak charged hadronic current in b decays is measured for the first time to be 2.69±\pm0.07(stat.)±\pm0.14(syst.). This result is in good agreement with the JETSET hadronization model of the weak charged hadronic current if 40±\pm17\% of the produced mesons are light--flavored tensor (L=1) mesons. This level of tensor meson production is consistent with the measurement of the π0\pi^0 multiplicity in the weak charged hadronic current in b decays. \end{abstract

    Measurement of the Average Lifetime of b-Hadrons in Z Decays

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    We present a measurement of the average b-hadron lifetime τb{\rm \tau_b} at the e+e\mathrm{e^+e^-} \, collider LEP. Using hadronic Z decays collected in the period from 1991 to 1994, two independent analyses have been performed. In the first one, the b-decay position is reconstructed as a secondary vertex of hadronic b-decay particles. The second analysis is an updated measurement of τb{\rm \tau_b} using the impact parameter of leptons with high momentum and high transverse momentum. The combined result is \begin{center} τb=[1549±9(stat)±15(syst)]  fs{\rm \tau_b= [ 1549 \pm 9 \, (stat) \, \pm 15 \, (syst) ] \; fs \,} . \end{center} In addition, we measure the average charged b-decay multiplicity nb{\rm \langle n_{\rm b}} \rangle and the normalized average b-energy xEb{\rm \langle x_E \rangle_{\rm b}} at LEP to be \begin{center} nb=4.90±0.04 (stat)±0.11(syst){\rm \langle n_{\rm b} \rangle = 4.90 \pm 0.04 \ (stat) \pm 0.11 \, (syst)} , \end{center} \begin{center} xEb=0.709±0.004(stat+syst).{\rm \langle x_E \rangle_{\rm b} = 0.709 \pm 0.004 \, (stat + syst).} \end{center

    Υ\Upsilon production in Z Decays

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    We have searched for evidence of Upsilon production in 3.5 million hadronic Z decays collected by the L3 detector at LEP in 1991-1995. No signals are observed for the decay chain Z -> Upsilon X; Upsilon -> l+l- (l= e, mu), therefore upper limits at the 95% confidence level are set on the following Z branching fractions: BR (Z -> Upsilon(1S) X) Upsilon(2S) X) Upsilon(3S) X) < 9.4 x 10**-5
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