552 research outputs found

    Calculation of nuclear spin-dependent parity-nonconserving amplitude for (7s,F=4) --> (7s,F=5) transition in Fr

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    Many-body calculation of nuclear spin-dependent parity-nonconserving amplitude for (7s,F=4) --> (7s,F=5) transition between hyperfine sublevels of the ground state of 211^{211}Fr is carried out. The final result is <7s,F=5 ||d_PNC|| 7s,F=4> = -0.49 10^{-10} i kappa a.u., where kappa is the dimensionless coupling constant. This is approximately an order of magnitude larger than similar amplitude in Cs. The dominant contribution to kappa is associated with the anapole moment of the nucleus.Comment: 4 pages, submitted to Phys.Rev.

    Resonances and O-curves in Hamiltonian systems

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    We investigate the problem of the existence of trajectories asymptotic to elliptic equilibria of Hamiltonian systems in the presence of resonances.Comment: 12 page

    Trapping polarization of light in nonlinear optical fibers: An ideal Raman polarizer

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    The main subject of this contribution is the all-optical control over the state of polarization (SOP) of light, understood as the control over the SOP of a signal beam by the SOP of a pump beam. We will show how the possibility of such control arises naturally from a vectorial study of pump-probe Raman interactions in optical fibers. Most studies on the Raman effect in optical fibers assume a scalar model, which is only valid for high-PMD fibers (here, PMD stands for the polarization-mode dispersion). Modern technology enables manufacturing of low-PMD fibers, the description of which requires a full vectorial model. Within this model we gain full control over the SOP of the signal beam. In particular we show how the signal SOP is pulled towards and trapped by the pump SOP. The isotropic symmetry of the fiber is broken by the presence of the polarized pump. This trapping effect is used in experiments for the design of new nonlinear optical devices named Raman polarizers. Along with the property of improved signal amplification, these devices transform an arbitrary input SOP of the signal beam into one and the same SOP towards the output end. This output SOP is fully controlled by the SOP of the pump beam. We overview the sate-of-the-art of the subject and introduce the notion of an "ideal Raman polarizer"

    Ultrahigh reflection from a medium with ultraslow group velocity

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    We show that an incident wavepacket at the boundary to a medium with extremely slow group velocity, experiences enhanced reflection and a substantial spatial and temporal distortion of the transmitted wave packet. In the limit of vanishing group velocity, light cannot be transferred into the medium due to its perfect reflectivity.Comment: 3 pages, 3 figure

    The Structure and Content Peculiarities of Carbon Material Obtained under the Polyacrylonitrile Infra-red Heating

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    It is first determined by the semiempirical quantum chemical model MNDO for a carbon material (CM) structure based on polyacrylonitrile (PAN) heat-treated that the increase of a content N from 14 to 18 atoms in CM monolayers C46N14H10, C44N16H12, and C42N18H14 and a content H from 12 to 22 atoms in CM monolayers C44N16H12 and C44N16H22 leads to the decrease of the binding energy (EB) from 7.40; 7.12 to 6.88 and 6.25 eV, respectively; and to the increase of the differences between the maximum and minimum bond lengths (∆l), between the maximum and minimum valence angles (∆Θ), and between the maximum and minimum local charges (∆q) from 0.176 Å; 12.0°, and 0.487 to 0.238 Å; 20.8°, and 0.613, respectively, and promotes the CM structure curvature. Quantum chemical simulation results are confirmed by the element analysis of CM samples and a nanocomposite FeNi3 / C. As the IR heating temperature is increased from 30 to 500 °С, concenrations N (СN) and H (СH) in the CM and nanocomposite FeNi3 / C are decreased from 27 to 18 and 10 wt % and from 6 to 1 and 0.5 wt %, respectively. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3364

    Limits on the monopole magnetic field from measurements of the electric dipole moments of atoms, molecules and the neutron

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    A radial magnetic field can induce a time invariance violating electric dipole moment (EDM) in quantum systems. The EDMs of the Tl, Cs, Xe and Hg atoms and the neutron that are produced by such a field are estimated. The contributions of such a field to the constants, χ\chi of the T,P-odd interactions χeNs/s\chi_e {\bf N} \cdot {\bf s}/s and χNNI/I\chi_N {\bf N} \cdot {\bf I}/I are also estimated for the TlF, HgF and YbF molecules (where s{\bf s} (I{\bf I}) is the electron (nuclear) spin and N{\bf N} is the molecular axis). The best limit on the contact monopole field can be obtained from the measured value of the Tl EDM. The possibility of such a field being produced from polarization of the vacuum of electrically charged magnetic monopoles (dyons) by a Coulomb field is discussed, as well as the limit on these dyons. An alternative mechanism involves chromomagnetic and chromoelectric fields in QCD.Comment: Uses RevTex, 16 pages, 4 postscript figures. An explanation of why there is no orbital contribution to the EDM has been added, and the presentation has been improved in genera

    The anapole moment and nucleon weak interactions

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    From the recent measurement of parity nonconservation (PNC) in the Cs atom we have extracted the constant of the nuclear spin dependent electron-nucleon PNC interaction, κ=0.442(63)\kappa = 0.442 (63); the anapole moment constant, κa=0.364(62)\kappa_a = 0.364 (62); the strength of the PNC proton-nucleus potential, gp=7.3±1.2(exp.)±1.5(theor.)g_p = 7.3 \pm 1.2 (exp.) \pm 1.5 (theor.); the π\pi-meson-nucleon interaction constant, fπhπ1=[9.5±2.1(exp.)±3.5(theor.)]×107f_\pi \equiv h_\pi^{1} = [9.5 \pm 2.1 (exp.) \pm 3.5 (theor.)] \times 10^{-7}; and the strength of the neutron-nucleus potential, gn=1.7±0.8(exp.)±1.3(theor.)g_n = -1.7 \pm 0.8 (exp.) \pm 1.3 (theor.).Comment: Uses RevTex, 12 pages. We have added an explanation of the effect of finite nuclear siz

    Local Optical Diagnostics of High-Temperature Gas Media Using Laser-Induced Gratings

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    Combined osteoplasty of metaepiphysial defects in total knee arthroplasty with osteoplastic biomaterial

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    The research goal is to study the results of osteoplastic biomaterials application to reach the improvement of primary and long-term secondary stability of fixation. Materials and methods: 62 patients with bone defect of metaepiphy-sis of type 2 according to AORI have been included into the research. Total knee arthroplasty with osteoplasty of the defect has been carried out in all the patients. In the basic group (n=32) combined osteoplasty has been used, and in comparison group (n=30) cement osteoplasty has been applied. In cases with total arthroplasty in the basic group modifying standard resections, structural autograft of laminar form has been received simultaneously. After preparing the floor of the defect its plasty has been carried out: in the basic group the defect has been filled with osteoconductive biomaterial, and in the comparison group — with polymethylmethacrylate to restore the anatomical configuration of condyles. Besides, before cement fixation of the prosthesis in the basic group the received autograft has been put on the restored implant plateau. Results: Assessing the results during the period from 2 to 4 years objective criteria have included the data of X-ray imaging, biomechanical research and WOMAC test. In the postoperative period significant differences have not been revealed. In the follow-up period in the group with application of the combined osteoplasty joint remodulation of autograft and osteoplastic biomaterial with regenerative restoration of bone tissue of the implant plateau has been observed. Conclusion: The described technique may reduce the relative risk of revision arthroplasty
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