2,106 research outputs found

    Failure criterion of glass fabric reinforced plastic laminates

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    Failure criteria are derived for several modes of failure (in unaxial tensile or compressive loading, or biaxial combined tensile-compressive loading) in the case of closely woven plain fabric, coarsely-woven plain fabric, or roving glass cloth reinforcements. The shear strength in the interaction formula is replaced by an equation dealing with tensile or compressive strength in the direction making a 45 degree angle with one of the anisotropic axes, for the uniaxial failure criteria. The interaction formula is useful as the failure criterion in combined tension-compression biaxial failure for the case of closely woven plain fabric laminates, but poor agreement is obtained in the case of coarsely woven fabric laminates

    Superconducting Gap Function in Antiferromagnetic Heavy-Fermion UPd_2Al_3 Probed by Angle Resolved Magnetothermal Transport Measurements

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    The superconducting gap structure of heavy fermion UPd_2Al_3, in which unconventional superconductivity coexists with antiferromagnetic (AF) order with atomic size local moments, was investigated by the thermal conductivity measurements in a magnetic field rotating in various directions relative to the crystal axes. The results provide strong evidence that the gap function \Delta(k) has a single line node orthogonal to the c-axis located at the AF Brillouin zone boundary, while \Delta(k) is isotropic within the basal plane. The determined nodal structure is compatible with the resonance peak in the dynamical susceptibility observed in neutron inelastic scattering experiments. Based on these results, we conclude that the superconducting pairing function of UPd_2Al_3 is most likely to be d-wave with a form \Delta(k)=\Delta_0 cos(k_zc)Comment: 10 pages, 9 figure

    Magnetic Properties of a Pressure-induced Superconductor UGe2_2

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    We performed the DC-magnetization and neutron scattering experiments under pressure {\it P} for a pressure-induced superconductor UGe2_2. We found that the magnetic moment is enhanced at a characteristic temperature {\it T}∗^{*} in the ferromagnetic state, where {\it T}∗^{*} is smaller than a Curie temperature {\it T}C_{\rm C}. This enhancement becomes remarkable in the vicinity of {\it P}C∗_{\rm C}^{*} = 1.20 GPa, where {\it T}∗^{*} becomes 0 K and the superconducting transition temperature {\it T}SC_{\rm SC} shows a maximum. The characteristic temperature {\it T}∗^{*}, which decreases with increasing pressure, also depends on the magnetic field.Comment: To be published in J.Phys.Soc.Jp

    Limb-Brightened Jet of 3C 84 Revealed by the 43-GHz Very-Long-Baseline-Array Observation

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    We present a study of sub-pc scale radio structure of the radio galaxy 3C 84/NGC 1275 based on the Very Long Baseline Array (VLBA) data at 43 GHz. We discover a limb-brightening in the "restarted" jet associated with the 2005 radio outburst. In the 1990s, the jet structure was ridge-brightening rather than limb-brightening, despite the observations being done with similar angular resolution. This indicates that the transverse jet structure has changed recently. This change in the morphology shows an interesting agreement with the γ\gamma-ray flux increase, i.e., the γ\gamma-ray flux in 1990s was at least seven times lower than the current one. One plausible explanation for the limb-brightening is the velocity structure of the jet in the context of the stratified jet, which is a successful scenario to explain the γ\gamma-ray emission in some active galactic nuclei (AGNs). If this is the case, the change in apparent transverse structure might be caused by the change in the transverse velocity structure. We argue the possibility that the transition from ridge-brightening to limb-brightening is related to the γ\gamma-ray time variability on the timescale of decades. We also discuss the collimation profile of the jet.Comment: 22 pages, 4 figures, Accepted for Publication in Ap

    Pressure-induced Superconductivity in a Ferromagnet UGe2_2 -- Resistivity Measurements in Magnetic Field --

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    The electrical resistivity measurements in the magnetic field are carried out on the pressure-induced superconductor UGe2_2. The superconductivity is observed from 1.06 to 1.44 GPa. The upper critical field of HC2H_{C2} is anisotropic where HC2(T)H_{C2}(T) exhibits positive curvature for H//bH//b and cc-axis. The characteristic enhancement of HC2H_{C2} is reconfirmed for H//aH//a-axis. In the temperature and field dependence of resistivity at P>PCP > P_{C} where the ferromagnetic ordering disappears, it is observed that the application of the external field along the {\it a}-axis increases the coefficient of Fermi liquid behavior AT2AT^{2} correspondingly to the metamagnetic transition.Comment: To be published in the proceeding of the International Conference on High Pressure Science and Technology(AIRAPT-18),Beijing,China,23-27 July 200

    Thermal transport in the hidden-order state of URu2_{2}Si2_{2}

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    We present a study of thermal conductivity in the normal state of the heavy-fermion superconductor URu2_{2}Si2_{2}. Ordering at 18K leads to a steep increase in thermal conductivity and (in contrast with all other cases of magnetic ordering in heavy-fermion compounds) to an enhancement of the Lorenz number. By linking this observation to several other previously reported features, we conclude that most of the carriers disappear in the ordered state and this leads to a drastic increase in both phononic and electronic mean-free-path.Comment: 5 pages including 4 figure
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