227 research outputs found

    Spin-Correlation Coefficients and Phase-Shift Analysis for p+3^3He Elastic Scattering

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    Angular Distributions for the target spin-dependent observables A0y_{0y}, Axx_{xx}, and Ayy_{yy} have been measured using polarized proton beams at several energies between 2 and 6 MeV and a spin-exchange optical pumping polarized 3^3He target. These measurements have been included in a global phase-shift analysis following that of George and Knutson, who reported two best-fit phase-shift solutions to the previous global p+3^3He elastic scattering database below 12 MeV. These new measurements, along with measurements of cross-section and beam-analyzing power made over a similar energy range by Fisher \textit{et al.}, allowed a single, unique solution to be obtained. The new measurements and phase-shifts are compared with theoretical calculations using realistic nucleon-nucleon potential models.Comment: Submitted to Phys. Rev.

    The role of age and digital competence on the use of online health and social care services : A cross-sectional population-based survey

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    Objective Online health and social care services are getting widespread which increases the risk that less advantaged groups may not be able to access these services resulting in digital exclusion. We examined the combined effects of age and digital competence on the use of online health and social care services. Methods We used a large representative population-based sample of 4495 respondents from Finland. Paper-based self-assessment questionnaire with an online response option was mailed to participants. The associations were analyzed using survey weighted logistic regression, exploring potential non-linear effects of age and controlling for potential sex differences. Results Higher age, starting from around the age of 60 was associated with a lower likelihood of using online services for receiving test results, renewing prescriptions and scheduling appointments. Good digital competence was able to hinder the age-related decline in online services use, but only up to around the age of 80. Conclusions Our results suggest that older adults are at risk of digital exclusion, and not even good digital competence alleviates this risk among the oldest. We suggest that health and social care providers should consider older users' needs and abilities more thoroughly and offer easy to use online services. More digital support and training possibilities should be provided for older people. It is equally important that face-to-face and telephone services will be continued to be provided for those older people who are not able to use online services even when supported.Peer reviewe

    The Three-Dipole Kicker Injection Scheme for the ALS-U Accumulator Ring

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    The ALS-U light source will implement on-axis single-train swap-out injection employing an accumulator between the booster and storage rings. The accumulator ring design is a twelve period triple-bend achromat that will be installed along the inner circumference of the storage-ring tunnel. A non-conventional injection scheme will be utilized for top-off off-axis injection from the booster into the accumulator ring meant to accommodate a large 300\sim 300~nm emittance beam into a vacuum-chamber with a limiting horizontal aperture radius as small as 88 mm. The scheme incorporates three dipole kickers distributed over three sectors, with two kickers perturbing the stored beam and the third affecting both the stored and the injected beam trajectories. This paper describes this ``3DK'' injection scheme and how it fits the accumulator ring's particular requirements. We describe the design and optimization process, and how we evaluated its fitness as a solution for booster-to-accumulator ring injection.Comment: 13 pages, 20 figure

    Specification and site control of the permeability of the cover concrete: the Swiss approach

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    It is recognized that most damage to reinforced concrete structures is caused by insufficient durability rather than by low strength. In most cases, the quality and thickness of the cover concrete (covercrete) determine the service life of the structure. Since the quality of the covercrete is influenced, not only by the mix composition, but also by the placing and curing conditions, it is appropriate to measure the achieved properties on the structure rather than just on separately cast specimens. Swiss Standard SIA 262 on Concrete Construction recommends checking the impermeability of the cover concrete on site. With that aim, a non-destructive method to measure the air-permeability on site has been standardized (SIA 262/1 Annex E). A team of Swiss experts was appointed by the Swiss Federal Highway Administration (ASTRA) to prepare recommendations for specifying, measuring, and assessing the conformity of the air-permeability kT. This paper describes these recommendations covering: (a) specification of limiting values of kT as function of the exposure class; (b) sampling of the measurement points; (c) testing (including suitable temperature and moisture conditions); (d) evaluation of conformity with specified values; (e) expected impact on service life

    Longitudinal phase space manipulation in energy recovering linac-driven free-electron lasers

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    Energy recovering an electron beam after it has participated in a free-electron laser (FEL) interaction can be quite challenging because of the substantial FEL-induced energy spread and the energy anti-damping that occurs during deceleration. In the Jefferson Lab infrared FEL driver-accelerator, such an energy recovery scheme was implemented by properly matching the longitudinal phase space throughout the recirculation transport by employing the so-called energy compression scheme. In the present paper,after presenting a single-particle dynamics approach of the method used to energy-recover the electron beam, we report on experimental validation of the method obtained by measurements of the so-called "compression efficiency" and "momentum compaction" lattice transfer maps at different locations in the recirculation transport line. We also compare these measurements with numerical tracking simulations.Comment: 31 pages, 13 figures, submitted to Phys. Rev. Special Topics A&

    Fluctuation-dissipation theorem and flux noise in overdamped Josephson junction arrays

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    The form of the fluctuation-dissipation theorem for a resistively shunted Josephson juction array is derived with the help of the method which explicitely takes into acoount screening effects. This result is used to express the flux noise power spectrum in terms of frequency dependent sheet impedance of the array. The relation between noise amplitude and parameters of the detection coil is analysed for the simplest case of a single-loop coil.Comment: ReVTeX, 8 page

    The fully frustrated XY model with next nearest neighbor interaction

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    We introduce a fully frustrated XY model with nearest neighbor (nn) and next nearest neighbor (nnn) couplings which can be realized in Josephson junction arrays. We study the phase diagram for 0x10\leq x \leq 1 (xx is the ratio between nnn and nn couplings). When x<1/2x < 1/\sqrt{2} an Ising and a Berezinskii-Kosterlitz-Thouless transitions are present. Both critical temperatures decrease with increasing xx. For x>1/2x > 1/\sqrt{2} the array undergoes a sequence of two transitions. On raising the temperature first the two sublattices decouple from each other and then, at higher temperatures, each sublattice becomes disorderd.Comment: 11 pages, 5 figure

    Dynamic Scaling of Magnetic Flux Noise Near the KTB Transition in Overdamped Josephson Junction Arrays

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    We have used a dc Superconducting QUantum Interference Device to measure the magnetic flux noise generated by the equilibrium vortex density fluctuations associated with the Kosterlitz-Thouless-Berezinskii (KTB) transition in an overdamped Josephson junction array. At temperatures slightly above the KTB transition temperature, the noise is white for f<fξf<f_\xi and scales as 1/f1/f for f>fξf>f_\xi. Here fξξzf_\xi\propto\xi^{-z}, where ξ\xi is the correlation length and zz is the dynamic exponent. Moreover, when all frequencies are scaled by fξf_\xi, data for different temperatures and frequencies collapse on to a single curve. In addition, we have extracted the dynamic exponent zz and found z=1.98±0.03z=1.98\pm0.03.Comment: 5 pages, LaTeX (REVTeX) format, requires epsfig and amstex style files. 3 figures included. Tentatively scheduled for publication in Physical Review Letters, 18 March, 199

    Temperature and Frequency Dependence of Complex Conductance of Ultrathin YBa2Cu3O7-x Films: A Study of Vortex-Antivortex Pair Unbinding

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    We have studied the temperature dependencies of the complex sheet conductance of 1-3 unit cell (UC) thick YBa2Cu3O7-x films sandwiched between semiconducting Pr0.6Y0.4Ba2Cu3O7-x layers at high frequencies. Experiments have been carried out in a frequency range between: 2 - 30 MHz with one-spiral coil technique, 100 MHz - 1 GHz frequency range with a new technique using the spiral coil cavity and at 30 GHz by aid of a resonant cavity technique. The real and imaginary parts of the mutual-inductance between a coil and a film were measured and converted to complex conductivity by aid of the inversion procedure. We have found a quadratic temperature dependence of the kinetic inductance, L_k^-1(T), at low temperatures independent of frequency, with a break in slope at T^dc_BKT, the maximum of real part of conductance and a large shift of the break temperature and the maximum position to higher temperatures with increasing frequency. We obtain from these data the universal ratio T^dc_BKT/L_k^-1(T^dc_BKT) = 25, 25, and 17 nHK for 1-, 2- and 3UC films, respectively in close agreement with theoretical prediction of 12 nHK for vortex-antivortex unbinding transition. The activated temperature dependence of the vortex diffusion constant was observed and discussed in the framework of vortex-antivortex pair pinning. PACS numbers: 74.80.Dm, 74.25.Nf, 74.72.Bk, 74.76.BzComment: PDF file, 10 pages, 6 figures, to be published in J. Low Temp. Phys.; Proc. of NATO ARW: VORTEX 200
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