4,949 research outputs found

    A ℘-order R-L high-pass filter modeled by local fractional derivative

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    Abstract As an important electronic device, filter is applied to all kinds of electronic products. In this paper, a new ℘ -order R-L High-pass filter (HPF) modeled by the local fractional derivative (LFD) is proposed for the first time. With the help of the local fractional Laplace transform (LFLT), we obtain the non-differentiable(ND) transfer function, and present the expressions of ND amplitude-frequency characteristic (AFC) and ND phase-frequency characteristics (PFC). The corresponding parameters and properties of the ℘ -order R-L HPF are also studied. What's interesting is that the ℘ -order R-L HPF becomesthe ordinary one in the exceptional case at ℘ = 1. The obtained results in this paper reveal the sufficiency of the local fractional derivative for analyzing the circuit systems in fractal space

    Two body final states production in electron-positron annihilation and their contributions to (g−2)μ(g-2)_{\mu}

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    In this paper, we study the processes of e+e−e^{+}e^{-} annihilation into two body final states, either two pseudoscalar mesons or one meson with a photon. The hadronic vacuum polarization form factors are calculated within the framework of resonance chiral theory in the energy region of E≲2E \lesssim 2 GeV, with final state interactions taken into account. A joint analysis on the processes of e+e−→π+π−e^{+}e^{-} \rightarrow \pi^{+}\pi^{-}, K+K−K^{+}K^{-}, KL0KS0K_{L}^{0}K_{S}^{0}, π0γ\pi^{0}\gamma, and ηγ\eta\gamma has been performed, and the latest experimental data are included. Based on the vacuum polarization form factors of these processes, we estimate their contributions to the lowest order of anomalous magnetic moment of the muon, (g−2)μ(g-2)_\mu. Combined with other contributions from hadronic vacuum polarization and other interactions from the standard model, the discrepancy between theoretical prediction and experimental measurement is Δaμ=(24.1±5.4)×10−10\Delta a_{\mu}=(24.1\pm5.4)\times 10^{-10}, i.e., 4.5σ\sigma.Comment: 45 pages, 6 figures, to be the same as the published versio

    1-(4-Fluoro­phen­yl)-3-hydr­oxy-3-phenyl­prop-2-en-1-one

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    In the crystal structure the title compound, C15H11FO2, the molecule exists in the enol form. It is stabilized by an intra­molecular O—H⋯O hydrogen bond, in which the donor O—H and acceptor H⋯O distances are almost equal. The dihedral angle between the two benzene rings is 22.30 (4)°

    Development of an Integrated Chip for Automatic Tracking and Positioning Manipulation for Single Cell Lysis

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    This study adopted a microelectromechanical fabrication process to design a chip integrated with electroosmotic flow and dielectrophoresis force for single cell lysis. Human histiocytic lymphoma U937 cells were driven rapidly by electroosmotic flow and precisely moved to a specific area for cell lysis. By varying the frequency of AC power, 15 V AC at 1 MHz of frequency configuration achieved 100% cell lysing at the specific area. The integrated chip could successfully manipulate single cells to a specific position and lysis. The overall successful rate of cell tracking, positioning, and cell lysis is 80%. The average speed of cell driving was 17.74 μm/s. This technique will be developed for DNA extraction in biomolecular detection. It can simplify pre-treatment procedures for biotechnological analysis of samples

    Impact of Clay Stabilizer on the Methane Desorption Kinetics and Isotherms of Longmaxi Shale, China

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    Knowing methane desorption characteristics is essential to define the contribution of adsorbed gas to gas well production. To evaluate the synthetic effect of a clay stabilizer solution on methane desorption kinetics and isotherms pertaining to Longmaxi shale, an experimental setup was designed based on the volumetric method. The objective was to conduct experiments on methane adsorption and desorption kinetics and isotherms before and after clay stabilizer treatments. The experimental data were a good fit for both the intraparticle diffusion model and the Freundlich isotherm model. We analyzed the effect of the clay stabilizer on desorption kinetics and isotherms. Results show that clay stabilizer can obviously improve the diffusion rate constant and reduce the methane adsorption amount. Moreover, we analyzed the desorption efficiency before and after treatment as well as the adsorbed methane content. The results show that a higher desorption efficiency after treatment can be observed when the pressure is higher than 6.84 MPa. Meanwhile, the adsorbed methane content before and after treatment all increase when the pressure decreases, and clay stabilizer can obviously promote the adsorbed methane to free gas when the pressure is lower than 19 MPa. This can also be applied to the optimization formulation of slickwater and the design of gas well production
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