14,447 research outputs found

    The diffusion pattern of non-cash payments: evidence from China

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    Exploiting an original dataset of non-cash payments during the period between 1996 and 2005, this study analyses the diffusion patterns of non-cash payments in China. Based on both exponential and Gompertz curves, the point of sale (POS) terminal has shown a higher diffusion rate than that of automatic teller machines (ATMs). This result is also robust when a time trend is interacted with rivals' precedence, network effects and market concentration. The diffusion rates of both ATM and POS terminals have accelerated after 2002, when UnionPay was established in China. The diffusion rate of ATMs is found to be mainly driven by rivals' adoption of them. Market concentration boosts the diffusion of POS terminals. In spite of the rising number of POS terminals and merchants, the volume of POS transactions is low. The diffusion rate of POS is, however, negatively affected by interchange fees

    Movement analysis of lower limb during backward walking with unstable intervention

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    Backward walking (BW), an emerging rehabilitative and training modality, was integrated with unstable sole construction with various hardness levels to analyze the kinematic and kinetic characteristics of the lower extremities. Eighteen participants volunteered to participate in the test. They performed walking tests under three conditions: 1) BW with normal shoes (NBW); 2) BW with unstable shoes with soft unstable elements (UBW-S); 3) BW with unstable shoes with hard unstable elements (UBW-H). The results show increased hip and ankle flexion and increased knee flexion-extension extent in the stance phase during BW with unstable shoes. The motor control mechanism of unstable BW enhanced the rehabilitation of lower limb deficiency. The attached unstable elements (UBW-S and UBW-H) induced local perturbation to stimulate proprioceptive ability and the neuromuscular system, changing the plantar loading distribution in a certain region. Future study should concentrate on the possible rehabilitative effect of unstable BW on neurological disorders and motor system deficiency

    Coplanar waveguide fed phased array antenna

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    A K-band four element linear phased array was designed and tested. Coplanar waveguide (CPW) is used for the microwave distribution system. A CPW to twin strip transition is used to interface with the printed dipole antennas. MMIC phased shifters are used for phase control

    The complex multiferroic phase diagram of Mn1x_{1-x}Cox_xWO4_4

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    The complete magnetic and multiferroic phase diagram of Mn1x_{1-x}Cox_{x}WO4_4 single crystals is investigated by means of magnetic, heat capacity, and polarization experiments. We show that the ferroelectric polarization P\overrightarrow{P} in the multiferroic state abruptly changes its direction twice upon increasing Co content, x. At xc1_{c1}=0.075, P\overrightarrow{P} rotates from the bb-axis into the aca-c plane and at xc2_{c2}=0.15 it flips back to the bb-axis. The origin of the multiple polarization flops is identified as an effect of the Co anisotropy on the orientation and shape of the spin helix leading to thermodynamic instabilities caused by the decrease of the magnitude of the polarization in the corresponding phases. A qualitative description of the ferroelectric polarization is derived by taking into account the intrachain (cc-axis) as well as the interchain (aa-axis) exchange pathways connecting the magnetic ions. In a narrow Co concentration range (0.1\leqx\leq0.15), an intermediate phase, sandwiched between the collinear high-temperature and the helical low-temperature phases, is discovered. The new phase exhibits a collinear and commensurate spin modulation similar to the low-temperature magnetic structure of MnWO4_4.Comment: 18 pages, 6 figure

    Spin tunnelling in mesoscopic systems

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    We study spin tunnelling in molecular magnets as an instance of a mesoscopic phenomenon, with special emphasis on the molecule Fe8. We show that the tunnel splitting between various pairs of Zeeman levels in this molecule oscillates as a function of applied magnetic field, vanishing completely at special points in the space of magnetic fields, known as diabolical points. This phenomena is explained in terms of two approaches, one based on spin-coherent-state path integrals, and the other on a generalization of the phase integral (or WKB) method to difference equations. Explicit formulas for the diabolical points are obtained for a model Hamiltonian.Comment: 13 pages, 5 figures, uses Pramana style files; conference proceedings articl

    Generalization of the Darboux transformation and generalized harmonic oscillators

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    The Darbroux transformation is generalized for time-dependent Hamiltonian systems which include a term linear in momentum and a time-dependent mass. The formalism for the NN-fold application of the transformation is also established, and these formalisms are applied for a general quadratic system (a generalized harmonic oscillator) and a quadratic system with an inverse-square interaction up to N=2. Among the new features found, it is shown, for the general quadratic system, that the shape of potential difference between the original system and the transformed system could oscillate according to a classical solution, which is related to the existence of coherent states in the system

    The evolution of the huntingtin-associated protein 40 (HAP40) in conjunction with huntingtin

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    Background The huntingtin-associated protein 40 (HAP40) abundantly interacts with huntingtin (HTT), the protein that is altered in Huntington's disease (HD). Therefore, we analysed the evolution of HAP40 and its interaction with HTT. Results We found that in amniotes HAP40 is encoded by a single-exon gene, whereas in all other organisms it is expressed from multi-exon genes. HAP40 co-occurs with HTT in unikonts, including filastereans such as Capsaspora owczarzaki and the amoebozoan Dictyostelium discoideum, but both proteins are absent from fungi. Outside unikonts, a few species, such as the free-living amoeboflagellate Naegleria gruberi, contain putative HTT and HAP40 orthologs. Biochemically we show that the interaction between HTT and HAP40 extends to fish, and bioinformatic analyses provide evidence for evolutionary conservation of this interaction. The closest homologue of HAP40 in current protein databases is the family of soluble N-ethylmaleimide-sensitive factor attachment proteins (SNAPs). Conclusion Our results indicate that the transition from a multi-exon to a single-exon gene appears to have taken place by retroposition during the divergence of amphibians and amniotes, followed by the loss of the parental multi-exon gene. Furthermore, it appears that the two proteins probably originated at the root of eukaryotes. Conservation of the interaction between HAP40 and HTT and their likely coevolution strongly indicate functional importance of this interaction

    Experimental investigation of the initial regime in fingering electrodeposition: dispersion relation and velocity measurements

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    Recently a fingering morphology, resembling the hydrodynamic Saffman-Taylor instability, was identified in the quasi-two-dimensional electrodeposition of copper. We present here measurements of the dispersion relation of the growing front. The instability is accompanied by gravity-driven convection rolls at the electrodes, which are examined using particle image velocimetry. While at the anode the theory presented by Chazalviel et al. describes the convection roll, the flow field at the cathode is more complicated because of the growing deposit. In particular, the analysis of the orientation of the velocity vectors reveals some lag of the development of the convection roll compared to the finger envelope.Comment: 11 pages, 15 figures, REVTEX 4; reference adde
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