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The thermophysical properties near the magnetic phase transition point is of great importance in the study of critical phenomenon. Low-dimensional materials are suggested to hold different thermophysical properties comparing to th...
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The thermophysical properties near the magnetic phase transition point is of great importance in the study of critical phenomenon. Low-dimensional materials are suggested to hold different thermophysical properties comparing to their bulk counterpart due to the dimension induced quantum confinement and anisotropy. In this work, we measured the thermal conductivity of alpha-Fe2O3 nanowires along the [110] direction (growing direction) with temperature from 100 to 150 K and found a dip of thermal conductivity near the Morin temperature. We found that the thermal conductivity near Morin temperature varies with the angle between magnetic field and the [110] direction of nanowire. More specifically, an angular-dependent thermal conductivity is observed, due to the magnetic field induced movement of the magnetic domain wall. The angle corresponding to the maximum of thermal conductivity varies near the Morin transition temperature, due to the different magnetic easy axis as suggested by our calculation based on magnetic anisotropy energy. This angular dependence of thermal conductivity indicates that the easy axis of alpha-Fe2O3 nanowires is different from bulk alpha-Fe2O3 due to the geometric anisotropy.
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We present scanning tunneling microscope (STM) measurements of the local electronic structure of superconducting granular aluminium films. The STM spectra show a homogeneously increased superconducting gap compared to that of alum...
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We present scanning tunneling microscope (STM) measurements of the local electronic structure of superconducting granular aluminium films. The STM spectra show a homogeneously increased superconducting gap compared to that of aluminum, both near and above the Mott resistivity rho(M) approximate to 400 mu Omega cm. Above rho(M) we find Coulomb charging effects, a first indication of electrical decoupling, and in-gap states on individual grains, which could contribute to flux noise and dielectric loss in quantum devices. We also observe multiple low-energy states outside the gap, which indicate bosonic excitations of an energy below twice the superconducting gap.
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A field theoretical renormalization group approach at two loop level is applied to the homogeneous spin-1 Bose gas in order to investigate the order of the phase transition. The beta function of the system with d = 4 - epsilon dim...
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A field theoretical renormalization group approach at two loop level is applied to the homogeneous spin-1 Bose gas in order to investigate the order of the phase transition. The beta function of the system with d = 4 - epsilon dimensions is determined tip to the third power of the coupling constants and the system's free energy on the border of the classical stability is given in next to leading order. It is found that the phase transition of the interacting spin-1 Bose gases with weak spin-dependent coupling constant values is of first order.
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The structure of the tetragonal phase of the A-site-substituted perovskite sodium bismuth titanate, Na0.5Bi0.5TiO3, has been determined by neutron powder diffraction at 698 K. The structure was refined in space group P4bm with a (...
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The structure of the tetragonal phase of the A-site-substituted perovskite sodium bismuth titanate, Na0.5Bi0.5TiO3, has been determined by neutron powder diffraction at 698 K. The structure was refined in space group P4bm with a (= b) = 5.5191 (1), c = 3.9085 (1) Angstrom, V = 119.055 (5) Angstrom(3), Z = 2 and D-x = 5.91 Mg m(-3). The structure exhibits an unusual combination of in-phase (a(0)a(0)c(+)) tilts and antiparallel cation displacements along the polar c axis, which results in a new variant of the perovskite structure. [References: 18]
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The transport and superconducting properties of Ba1 - x K (x) Fe2As2 single crystals with T (c) a parts per thousand 31 K were studied. Both in-plane and out-of-plane resistivity was measured by a modified Montgomery method. The i...
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The transport and superconducting properties of Ba1 - x K (x) Fe2As2 single crystals with T (c) a parts per thousand 31 K were studied. Both in-plane and out-of-plane resistivity was measured by a modified Montgomery method. The in-plane resistivity is almost the same for all studied samples, unlike the out-of-plane resistivity, which differs considerably. We have found that the resistivity anisotropy gamma = rho (c) /rho (ab) is almost independent of temperature and lies in the range 10-30 for the studied samples. This indicates the extrinsic nature of high out-of-plane resistivity, which may be due to the presence of flat defects along Fe-As layers in the samples. This statement is supported by comparatively small effective mass anisotropy, obtained from the upper critical field measurements, and from the observation of the so-called "Friedel transition," which indicates the existence of some disorder in the samples in the c-direction.
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Physical properties of the organic charge-transfer complex that may be regarded as a doping system are presented. We measured resistivity of an ambient-pressure superconductor, kappa-(BEDT-TTF)(4)Hg2.89Br8, as functions of tempera...
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Physical properties of the organic charge-transfer complex that may be regarded as a doping system are presented. We measured resistivity of an ambient-pressure superconductor, kappa-(BEDT-TTF)(4)Hg2.89Br8, as functions of temperature, magnetic field, and pressure. Metallic and superconducting states of this salt are possibly attributable to the doping effect, which originates from incommensurability of Hg chain because band structure calculation predicts strong electron-electron correlation enough to localize the itinerant electrons. We uncovered anomalous pressure and magnetic field dependences of superconductivity as well as non-Fermi liquid behavior in the normal-state resistivity at low pressures. In addition, we observed a pressure-induced crossover to the Fermi liquid behavior, which is seen in non-doped kappa-type salts at any pressures.
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TMCT (Thermal Mechanical Compression Test) was applied to measure the T_(g-r) (glass-rubber transition temperature) of rice flour and individual rice kernels at low moisture content (2.4-19.5% wet basis). As expected, T_(g-r) decr...
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TMCT (Thermal Mechanical Compression Test) was applied to measure the T_(g-r) (glass-rubber transition temperature) of rice flour and individual rice kernels at low moisture content (2.4-19.5% wet basis). As expected, T_(g-r) decreased with increasing moisture content. The T_(g-r) temperatures measured by TMCT were comparable with those measured by DSC (Differential Scanning Calorimetry), TMA (Thermo-mechanical Analysis), and DMTA (Dynamic Mechanical Thermal Analysis) as reported in the literature. These results indicated that the TMCT technique could be applied to measure the glass-rubber transition of a single grain of rice or the rice in powder form. The sensitivity of the test was observed higher for the rice kernel than rice flour. TMCT technique has the advantage of usefulness and cost-effectiveness compared with the other techniques.
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? 2024 Elsevier LtdThis paper is dedicated to the ductile–brittle transition behaviour of the microalloyed structural steel NIOMOL 490 K. This steel grade is used for welded pressure vessels subjected to dynamic loads and operati...
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? 2024 Elsevier LtdThis paper is dedicated to the ductile–brittle transition behaviour of the microalloyed structural steel NIOMOL 490 K. This steel grade is used for welded pressure vessels subjected to dynamic loads and operating at sub-zero temperatures. Therefore, it must have an acceptable toughness. Due to its importance for the safety assessment of pressure vessels, a characterization of this steel was carried out using the Charpy V-notch impact test in the temperature range between ?60 °C and + 60 °C. The notches were located in parent material, heat affected zone and weld metal. In this paper, the tensile strength properties at ambient temperature and the nil ductility temperature in the temperature range from ?60 °C to + 60 °C are presented.
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The relationship between Indian Ocean sea surface temperature and the transition of El Nino events into either La Nina or El Nino-Southem Oscillation neutral conditions is examined in both observations and the retrospective ensemb...
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The relationship between Indian Ocean sea surface temperature and the transition of El Nino events into either La Nina or El Nino-Southem Oscillation neutral conditions is examined in both observations and the retrospective ensemble hindcasts of the National Center for Environmental Prediction Climate Forecast System. The southern Indian Ocean is shown to demonstrate a particularly robust and consistent relationship with the evolution of these transitions. These associations are described, and a physical mechanism involving air-sea interaction in the Indian and western Pacific Oceans is proposed. Observations suggest that easterly surface wind anomalies in the western Pacific Ocean are associated with the emergence of La Nina during boreal summer and fall. Here it is shown that these winds are significantly correlated to southern Indian Ocean sea surface temperature in the preceding spring that is characterized by a large-scale zonal dipole of cool and warm anomalies in the southwestern and southeastern Indian Oceans, respectively. These associations are particularly pronounced for strong El Nino conditions, during the dissipation of which a pronounced wavetrain-like atmospheric pattern accompanies sea surface temperature anomalies in the southern Indian Ocean. Together, the circulation and sea surface temperature anomalies increase the meridional cross-equatorial temperature gradient in the western Indian Ocean and mute intraseasonal variability while strengthening surface equatorial easterly winds in the Indo-Pacific warm pool. Collectively, these anomalies favor subsequent La Nina development. On the basis of these observed associations, a predictive model that demonstrates skill in anticipating the nature of El Nino transitions, involving the southern Indian Ocean, Asian monsoon, and El Milo—Southern Oscillation, is proposed. In the National Center for Environmental Prediction Climate Forecast System, the relationships described above are simulated both consistently and realistically, despite model weaknesses, further bolstering a key role of southern Indian Ocean and predictive relationship. Comparison of fully coupled and sea surface temperature-forced simulations suggests a key role for air-sea interaction in the observed associations. Moreover, it is demonstrated that coupled simulations of El Nino-Southern Oscillation may benefit substantially from improved representation of Indian Ocean variability and Indo-Pacific interaction.
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According to the Anderson theorem, the critical temperature T_c of a disordered superconductor is determined by the average density of states and does not change at the localization threshold. This statement is valid under assumpt...
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According to the Anderson theorem, the critical temperature T_c of a disordered superconductor is determined by the average density of states and does not change at the localization threshold. This statement is valid under assumption of a self-averaging order parameter, which can be violated in the strong localization region. Stimulating by statements on the essential increase of T_c near the Anderson transition, we carried out the systematic investigation of possible violations of self-averaging. Strong deviations from the Anderson theorem are possible due to resonances at the quasi-discrete levels, resulting in localization of the order parameter at the atomic scale. This effect is determined by the properties of individual impurities and has no direct relation to the Anderson transition. In particular, we do not see any reasons to say on “fractal superconductivity” near the localization threshold.
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