5,487 research outputs found

    Spheres and Prolate and Oblate Ellipsoids from an Analytical Solution of Spontaneous Curvature Fluid Membrane Model

    Full text link
    An analytic solution for Helfrich spontaneous curvature membrane model (H. Naito, M.Okuda and Ou-Yang Zhong-Can, Phys. Rev. E {\bf 48}, 2304 (1993); {\bf 54}, 2816 (1996)), which has a conspicuous feature of representing the circular biconcave shape, is studied. Results show that the solution in fact describes a family of shapes, which can be classified as: i) the flat plane (trivial case), ii) the sphere, iii) the prolate ellipsoid, iv) the capped cylinder, v) the oblate ellipsoid, vi) the circular biconcave shape, vii) the self-intersecting inverted circular biconcave shape, and viii) the self-intersecting nodoidlike cylinder. Among the closed shapes (ii)-(vii), a circular biconcave shape is the one with the minimum of local curvature energy.Comment: 11 pages, 11 figures. Phys. Rev. E (to appear in Sept. 1999

    Generalized W-Class State and its Monogamy Relation

    Full text link
    We generalize the W class of states from nn qubits to nn qudits and prove that their entanglement is fully characterized by their partial entanglements even for the case of the mixture that consists of a W-class state and a product state ∣0⟩⊗n\ket{0}^{\otimes n}.Comment: 12 pages, 1 figur

    Hertz-level Measurement of the 40Ca+ 4s 2S1/2-3d 2D5/2 Clock Transition Frequency With Respect to the SI Second through GPS

    Full text link
    We report a frequency measurement of the clock transition of a single ^40Ca^+ ion trapped and laser cooled in a miniature ring Paul trap with 10^-15 level uncertainty. In the measurement, we used an optical frequency comb referenced to a Hydrogen maser, which was calibrated to the SI second through the Global Positioning System (GPS). Two rounds of measurements were taken in May and June 2011, respectively. The frequency was measured to be 411 042 129 776 393.0(1.6) Hz with a fractional uncertainty of 3.9{\times}10^-15 in a total averaging time of > 2{\times}10^6 s within 32 days

    The Relationship Between Birch Pollen, Air Pollution and Weather Types and Their Effect on Antihistamine Purchase in Two Swedish Cities

    Get PDF
    Exposure to elevated air pollution levels can aggravate pollen allergy symptoms. The aim of this study was to investigate the relationships between airborne birch (Betula) pollen, urban air pollutants NO2, O3 and PM10 and their effects on antihistamine demand in Gothenburg and Malmo¨, Sweden, 2006–2012. Further, the influence of large-scale weather pattern on pollen-/ pollution-related risk, using Lambweather types (LWTs), was analysed. Daily LWTs were obtained by comparing the atmospheric pressure over a 16-point grid system over southern Sweden (scale *3000 km). They include two non-directional types, cyclonic (C) and anticyclonic (A) and eight directional types depending on the wind direction (N, NE, E…). Birch pollen levels were exceptionally high under LWTs E and SE in both cities. Furthermore, LWTs with dry and moderately calm meteorological character (A, NE, E, SE) were associated with strongly elevated air pollution (NO2 and PM10) in Gothenburg. For most weather situations in both cities, simultaneously high birch pollen together with high air pollution had larger over-the-counter (OTC) sales of antihistamines than situations with high birch pollen alone. LWTs NE, E, SE and S had the highest OTC sales in both cities. InGothenburg, the city with a higher load of both birch pollen and air pollution, the higher OTC sales were especially obvious and indicate an increased effect on allergic symptoms from air pollution. Furthermore, GothenburgLWTs A, NE, E and SEwere associatedwith high pollen and air pollution levels and thus classified as high-risk weather types. In Malmo¨, corresponding highrisk LWTs were NE, E, SE and S. Furthermore, occurrence of high pollen and air pollutants as well as OTC sales correlated strongly with vapour pressure deficit and temperature in Gothenburg (much less so in Malmo¨). This provides evidence that the combination of meteorological properties associated with LWTs can explain high levels of birch pollen and air pollution. Our study shows that LWTs represent a useful tool for integrated daily air quality forecasting/warning

    A Dispersive Analysis on the f0(600)f_0(600) and f0(980)f_0(980) Resonances in γγ→π+π−,π0π0\gamma\gamma\to\pi^+\pi^-, \pi^0\pi^0 Processes

    Full text link
    We estimate the di-photon coupling of f0(600)f_0(600), f0(980)f_0(980) and f2(1270)f_2(1270) resonances in a coupled channel dispersive approach. The f0(600)f_0(600) di-photon coupling is also reinvestigated using a single channel TT matrix for ππ\pi\pi scattering with better analyticity property, and it is found to be significantly smaller than that of a qˉq\bar qq state. Especially we also estimate the di-photon coupling of the third sheet pole located near KˉK\bar KK threshold, denoted as f0III(980)f_0^{III}(980). It is argued that this third sheet pole may be originated from a coupled channel Breit-Wigner description of the f0(980)f_0(980) resonance.Comment: 24 pages and 13 eps figures. A nuerical bug in previous version is fixed. Some results changed. References and new figures added. Version to appear in Phys. Rev.

    Quantum Communication with Correlated Nonclassical States

    Get PDF
    Nonclassical correlations between the quadrature-phase amplitudes of two spatially separated optical beams are exploited to realize a two-channel quantum communication experiment with a high degree of immunity to interception. For this scheme, either channel alone can have an arbitrarily small signal-to-noise ratio (SNR) for transmission of a coherent ``message''. However, when the transmitted beams are combined properly upon authorized detection, the encoded message can in principle be recovered with the original SNR of the source. An experimental demonstration has achieved a 3.2 dB improvement in SNR over that possible with correlated classical sources. Extensions of the protocol to improve its security against eavesdropping are discussed.Comment: 8 pages and 4 figures (Figure 1; Figures 2a, 2b; Figure 2

    Synthesis and Application of Magnetic Photocatalyst of Ni-Zn Ferrite/TiO 2

    Get PDF
    IC lead frame scraps with about 18.01% tin, 34.33% nickel, and 47.66% iron in composition are industrial wastes of IC lead frame production. The amount of thousand tons of frame scraps in Taiwan each year is treated as scrap irons. Ni-Zn ferrites used in high frequent inductors and filters are produced from Ni-Zn ferrite powders by pressing and sintering. The amount of several ten thousand tons of ferrites of Ni1-XZnXFe2O4 in compositions is consumed annually in the whole world. Therefore, these IC lead frame scraps will be used in this research as raw materials to fabricate magnetic ferrite powders and combined subsequently with titanium sulfate and urea to produce magnetic photocatalysts by coprecipitation for effective waste utilization. The prepared Ni-Zn ferrite powder and magnetic photocatalyst (Ni-Zn ferrite/TiO2) were characterized by ICP, XRF, XRD, EDX, SEM, SQUID, and BET. The photocatalytic activity of synthesized magnetic photocatalysts was tested by FBL dye wastewater degradation. TOC and ADMI measurement for degradation studies were carried out, respectively. Langmuir-Hinshelwood kinetic model of the prepared magnetic TiO2 proved available for the treatments. Wastes are transformed to valuable magnetic photocatalysts in this research to solve the separation problem of wastewater and TiO2 photocatalysts by magnetic field
    • …
    corecore