802 research outputs found

    Features and Cost Comparison of Biologically Inspired Vision Systems

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    The economic analysis of the advantages of known analogues of biologically inspired systems for unmanned aerial vehicles (UAVs), quadrocopters, etc

    Critical parameters of N-vector spin models on 3d lattices from high temperature series extended to order beta^{21}

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    High temperature expansions for the free energy, the susceptibility and the second correlation moment of the classical N-vector model [also denoted as the O(N) symmetric classical spin Heisenberg model or as the lattice O(N) nonlinear sigma model] have been extended to order beta^{21} on the simple cubic and the body centered cubic lattices, for arbitrary N. The series for the second field derivative of the susceptibility has been extended to order beta^{17}. An analysis of the newly computed series yields updated estimates of the model's critical parameters in good agreement with present renormalization group estimates.Comment: 3 pages, Latex,(fleqn.sty, espcrc2.sty) no figures, contribution to Lattice'97 to appear in Nucl. Phys. Proc. Supp

    Critical behavior of frustrated systems: Monte Carlo simulations versus Renormalization Group

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    We study the critical behavior of frustrated systems by means of Pade-Borel resummed three-loop renormalization-group expansions and numerical Monte Carlo simulations. Amazingly, for six-component spins where the transition is second order, both approaches disagree. This unusual situation is analyzed both from the point of view of the convergence of the resummed series and from the possible relevance of non perturbative effects.Comment: RevTex, 10 pages, 3 Postscript figure

    Quasifission and difference in formation of evaporation residues in the 16^{16}O+184^{184}W and 19^{19}F+181^{181}Ta reactions

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    The excitation functions of capture, complete fusion, and evaporation residue formation in the 16^{16}O+184^{184}W and 19^{19}F+181^{181}Ta reactions leading to the same 200^{200}Pb compound nucleus has been studied theoretically to explain the experimental data showing more intense yield of evaporation residue in the former reaction in comparison with that in the latter reaction. The observed difference is explained by large capture cross section in the former and by increase of the quasifission contribution to the yield of fission-like fragments in the 19^{19}F+181^{181}Ta reaction at large excitation energies. The probability of compound nucleus formation in the 16^{16}O+184^{184}W reaction is larger but compound nuclei formed in both reactions have similar angular momentum ranges at the same excitation energy. The observed decrease of evaporation residue cross section normalized to the fusion cross section in the 19^{19}F+181^{181}Ta reaction in comparison with the one in the 16^{16}O+184^{184}W reaction at high excitation energies is explained by the increase of hindrance in the formation of compound nucleus connected with more quick increase of the quasifission contribution in the 19^{19}F induced reaction. The spin distributions of the evaporation residue cross sections for the two reactions are also presented.Comment: 11 pages, 5 figure

    Monte Carlo renormalization group study of the Heisenberg and XY antiferromagnet on the stacked triangular lattice and the chiral Ο•4\phi^4 model

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    With the help of the improved Monte Carlo renormalization-group scheme, we numerically investigate the renormalization group flow of the antiferromagnetic Heisenberg and XY spin model on the stacked triangular lattice (STA-model) and its effective Hamiltonian, 2N-component chiral Ο•4\phi^4 model which is used in the field-theoretical studies. We find that the XY-STA model with the lattice size 126Γ—144Γ—126126\times 144 \times 126 exhibits clear first-order behavior. We also find that the renormalization-group flow of STA model is well reproduced by the chiral Ο•4\phi^4 model, and that there are no chiral fixed point of renormalization-group flow for N=2 and 3 cases. This result indicates that the Heisenberg-STA model also undergoes first-order transition.Comment: v1:15 pages, 15 figures v2:updated references v3:added comments on the higher order irrelevant scaling variables v4:added results of larger sizes v5:final version to appear in J.Phys.Soc.Jpn Vol.72, No.

    High magnetomechanical coupling on magnetic microwire for sensors with biological applications

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    In this letter, we report the experimental work carried out to study and improve the magnetomechanical coupling on magnetic microwires. A good magnetoelastic response, with magnetoelastic coupling factor k=0.43, has been obtained by control of both wire diameter and sample microstructure. The study addresses two following aspects: (a) analysis of the suitability of amorphous magnetoelastic microwire as promising tiny sensor element to be used as wireless biosensors as well as environment detectors. In particular, its potential as liquids viscosity sensor has been confirmed. (b) Study, as the first time in this kind of magnetic microwire, of the effects of nanocrystallization on the sample magnetoelastic behavior

    Psychogenic dizziness

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    Psychogenic dizziness is one of the most common types of vertigo. To diagnose psychogenic dizziness is a complex task since it requires a thorough patient examination and exclusion of possible organic causes of dizziness. The paper describes the clinical case of a female patient with phobic postural vertigo, which demonstrates the efficiency of the early diagnosis and adequate therapy of this disease. Combination therapy for psychogenic dizziness, which encompasses different psychotherapeutic procedures, vestibular rehabilitation, and drug therapy, is most effective. Among the medications, vinpocetine is effective in treating patients with cerebrovascular disease. Inappropriate treatment may lead to the progression of psychogenic dizziness, to a considerable deterioration in quality of life, and to obvious social disadaptation. There is a worse treatment prognosis with a longer interval between of disease onset and diagnosis
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