219 research outputs found

    Magnetic loop antenna with electronic tuning for frequencies below 30MHz

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    Tento projekt se zabĂœvĂĄ nĂĄvrhem elektronickĂ©ho laděnĂ­ a automatizovanĂ©ho pƙizpĆŻsobenĂ­ magnetickĂœch, smyčkovĂœch antĂ©n, pracujĂ­cĂ­ch v oblasti krĂĄtkĂœch vln. CelĂĄ prĂĄce je rozdělena do tƙí částĂ­ (ladĂ­cĂ­, pƙizpĆŻsobovacĂ­ a ƙídĂ­cĂ­). LadĂ­cĂ­ část je realizovanĂĄ změnou kapacity pomocĂ­ kaskĂĄdy kondenzĂĄtorĆŻ a pƙizpĆŻsobovĂĄnĂ­ je provedeno rĆŻznĂœmi změnami bodĆŻ napĂĄjenĂ­. CelĂœ systĂ©m je ƙízen mikroprocesorem ATmega16. Dle poĆŸadavkĆŻ obsluĆŸnĂ©ho programu, spĂ­nĂĄ mikroprocesor pƙísluĆĄnĂ© kapacity, čímĆŸ ladĂ­ antĂ©nu na potƙebnĂœ kmitočet, pracovĂĄvĂĄ informace o vĂœkonovĂ©m pƙizpĆŻsobenĂ­ a automaticky dolaďuje antĂ©nu změnou polohy napĂĄjenĂ­.This project deals with electronic tuning and automated adjustment of magnetic loop antennas, working in the High Frequencys. The whole work is divided into three parts tuning, adjustment and control). The tuning part is realized by changing the capacity of the array capacitors and adjustment is done by different changes of power points. The whole system is controlled by a microprocessor ATmega16. According to utility switches the microprocessor capacity, which tunes the antenna to the required frequency, processes information about power adjustment and autimatically fine-tuning the antenna by changing the position of charging.

    ‘Sub-Prime’ Water, Low-Security Entitlements and Policy Challenges in Over-Allocated River Basins: the Case of the Murray–Darling Basin

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    Environmental policy is often implemented using market instruments. In some cases, including carbon taxing, the links between financial products and the environmental objectives, are transparent. In other cases, including water markets, the links are less transparent. In Australia’s Murray–Darling Basin (MDB), financial water products are known as ‘entitlements’, and are similar to traditional financial products, such as shares. The Australian water market includes ‘Low Security’ entitlements, which are similar to ‘sub-prime’ mortgage bonds because they are unlikely to yield an amount equal to their financial worth. Nearly half the water purchased under the Murray–Darling Basin Plan for environmental purposes is ‘Low Security’. We suggest that the current portfolio of water held by the Australian Government for environmental purposes reflects the mortgage market in the lead-up to the global financial crisis. Banks assumed that the future value of the mortgage market would reflect past trends. Similarly, it is assumed that the future value of water products will reflect past trends, without considering climate change. Historic records of allocations to ‘Low Security’ entitlements in the MDB suggest that, in the context of climate change, the Basin Plan water portfolio may fall short of the target annual average yield of 2075 GL by 511 GL. We recommend adopting finance sector methods including ‘hedging’ ‘Low Security’ entitlements by purchasing an additional 322–2755 GL of ‘Low Security’, or 160–511 GL of ‘High Security’ entitlements. Securing reliable environmental water is a global problem. Finance economics present opportunities for increasing the reliability of environmental flows

    Modelling credit spreads with time volatility, skewness, and kurtosis

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    This paper seeks to identify the macroeconomic and financial factors that drive credit spreads on bond indices in the US credit market. To overcome the idiosyncratic nature of credit spread data reflected in time varying volatility, skewness and thick tails, it proposes asymmetric GARCH models with alternative probability density functions. The results show that credit spread changes are mainly explained by the interest rate and interest rate volatility, the slope of the yield curve, stock market returns and volatility, the state of liquidity in the corporate bond market and, a heretofore overlooked variable, the foreign exchange rate. They also confirm that the asymmetric GARCH models and Student-t distributions are systematically superior to the conventional GARCH model and the normal distribution in in-sample and out-of-sample testing

    Test of lepton universality in b→sℓ+ℓ−b \rightarrow s \ell^+ \ell^- decays

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    The first simultaneous test of muon-electron universality using B+→K+ℓ+ℓ−B^{+}\rightarrow K^{+}\ell^{+}\ell^{-} and B0→K∗0ℓ+ℓ−B^{0}\rightarrow K^{*0}\ell^{+}\ell^{-} decays is performed, in two ranges of the dilepton invariant-mass squared, q2q^{2}. The analysis uses beauty mesons produced in proton-proton collisions collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of 9 fb−1\mathrm{fb}^{-1}. Each of the four lepton universality measurements reported is either the first in the given q2q^{2} interval or supersedes previous LHCb measurements. The results are compatible with the predictions of the Standard Model.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-046.html (LHCb public pages

    Precision measurement of CP\it{CP} violation in the penguin-mediated decay Bs0→ϕϕB_s^{0}\rightarrow\phi\phi

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    A flavor-tagged time-dependent angular analysis of the decay Bs0→ϕϕB_s^{0}\rightarrow\phi\phi is performed using pppp collision data collected by the LHCb experiment at % at s=13\sqrt{s}=13 TeV, the center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 6 fb^{-1}. The CP\it{CP}-violating phase and direct CP\it{CP}-violation parameter are measured to be ϕssˉs=−0.042±0.075±0.009\phi_{s\bar{s}s} = -0.042 \pm 0.075 \pm 0.009 rad and ∣λ∣=1.004±0.030±0.009|\lambda|=1.004\pm 0.030 \pm 0.009 , respectively, assuming the same values for all polarization states of the ϕϕ\phi\phi system. In these results, the first uncertainties are statistical and the second systematic. These parameters are also determined separately for each polarization state, showing no evidence for polarization dependence. The results are combined with previous LHCb measurements using pppp collisions at center-of-mass energies of 7 and 8 TeV, yielding ϕssˉs=−0.074±0.069\phi_{s\bar{s}s} = -0.074 \pm 0.069 rad and ∣lambda∣=1.009±0.030|lambda|=1.009 \pm 0.030. This is the most precise study of time-dependent CP\it{CP} violation in a penguin-dominated BB meson decay. The results are consistent with CP\it{CP} symmetry and with the Standard Model predictions.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2023-001.html (LHCb public pages
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