In this paper, we have investigated the TRANSPORT properties of the Dirac fermions on a topological insulator surface in the presence of external electric and MAGNETIC fields. For this reason, firstly we obtain the eigen energies (or eigenvalues) by using the Dirac Hamiltonian of the system for transmitted electrons via the surface and the Lorentz transformations. The conductance of the system is calculated by Landauer equation. Also, the effects of electric and MAGNETIC fields are investigated on the conductance and Fano factor effect. The application of the present results may be useful in designing devices based on molecular electronics in nanoscale.

Single phase polycrystalline Gd1-xPrxBa2Cu3O7-δ samples with x= 0.05, 0.10, and 0.15 have been prepared by standard solid state reaction technique and characterized by XRD and SEM analysis. The electrical resistivity, Hall effect and magnetoresistance measurements have been made on the samples. The electrical resistivity measurements indicate a reduction of transition temperature (Tc) and an increase of superconducting transition width with increasing x. Hall measurements show anomalous temperature dependence for Hall coefficient (RH) in the normal state. In Gd0.90Pr0.10Ba2Cu3O7-δ sample, we have seen an anomalous sign reversal in the Hall coefficient with respect to temperature. The magnetoresistance measurements in the range of 0 to 10 kOe also show small changes in the normal states, although the changes are large in the superconducting state. An anomaly at 260 K appears in the transverse magnetoresistance for x=0.1 sample, which is related to the presence of MAGNETIC Gd ion. The superconducting transition width also increases with the MAGNETIC field in all of the samples. An exponent behavior for Hc2 versus (1- T/T0(H)) and superconducting transition width versus H have been derived. Pinning energy (U) has also been calculated from these measurements. Results show the reduction of pinning energy with the increase of MAGNETIC field and x. Our results show that the exponent behavior of U ∞ HV, where v is independent of x.

Background and Aims: Disc displacement is the most common temporomandibular joint disorder and MAGNETIC resonance imaging (MRI) is the gold standard in its diagnosis. This disorder can lead to changes in signal intensity of MAGNETIC resonance (MR). The purpose of this study was evaluation of correlation between relative signal intensity of MR images of retrodiscal tissue, superior and inferior head of lateral ptrygoid muscle with type of anterior disk displacement and condylar head flattening in patients with temporomandibular disorder (TMD).Materials and Methods: In this retrospective study, 31 MR images of patients who had anterior disc displacement were evaluated. After relative signal intensity measurement for retrodiscal tissue, superior and inferior head of lateral ptrygoid muscle, the correlation between relative signal intensity and type of anterior disc displacement was evaluated with repeated measure ANOVA test. In each of these 3 areas, t-test was used to compare the groups with and without condylar head flattening.Results: The correlation between relative signal intensity of MR images and type of anterior disc displacement in retrodiscal tissue, superior and inferior head of lateral ptrygoid muscle was not significant. There was also no statistically significant correlation between relative signal intensity of MR images and flattening of condylar head in retrodiscal tissue, superior and inferior head of lateral ptrygoid muscle (P>0.05).Conclusion: According to findings of this study, relative signal intensity of MR images in retrodiscal tissue, superior and inferior head of ptrygoid muscle is not a good predictor for type of anterior disc displacement and flattening of condylar head. It seems that this cannot be used as a diagnostic marker for TMD progression.

MAGNETIC resonance imaging (MRI) has tremendous potential for revealing TRANSPORT processes in engineered and geologic systems. Here, we utilize MRI to image nanoparticle (NP) TRANSPORT through a saturated coarse-grained system. Commercially available paraMAGNETICally tagged NPs are used; the paraMAGNETIC tag making the NP visible to MRI. NP TRANSPORT was imaged as NPs migrated through packed columns of quartz and dolomite gravel. Changes in T2-weighted image intensity were calibrated to provide fully quantitative maps of NP concentration at regular time intervals (T 2being the spin–spin relaxation time of 1H nuclei). TRANSPORT of nanoparticles was significantly retarded in dolomite compared to quartz due to electrostatic attraction between nanoparticle and dolomite surfaces. NP concentration profiles were evaluated with the CXTFIT computer package to estimate nanoparticle TRANSPORT parameters at multiple points along the length of the column. This provided temporally resolved parameters that standard breakthrough curve analysis cannot provide. Particle–surface interaction energy profiles were described through Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. While dispersion coefficients and fast deposition rate constant (k fast) were found to increase with distance, deposition rate constant (k) and collision efficiency (a) were found to decrease with distance. These length-dependant variations have significant scaling-up implications for TRANSPORT models used to predict NP TRANSPORT in natural and engineered coarse-grained systems, such as sustainable urban drainage systems and river beds.

In the current study, a MAGNETIC-boiling driven heat TRANSPORT device has been introduced and modeled numerically. The numerical modeling of the problem has been carried out using Eulerian-Eulerian two phase model and control volume technique. The numerical results showed that a flow of MAGNETIC nanofluid can be induced and drove inside a horizontal tube in the existence of MAGNETIC field (MF) which is due to variations made in the magnetization of the ferrofluid by generation of the vapor bubbles during boiling process. The obtained results also showed that the simulated heat TRANSPORT device powered based on MAGNETIC-boiling induction is not only able to pump the ferrofluid through the tube, but also is able to transfer a considerable amount of heat generated in the electronic chip (heat source) as well. Furthermore, the flow rate of the induced flow inside the tube increases as the heat input of the heat source is increased. The heat source can be due to existence of a high heat flux electronic chip and the chip temperature (wall of the heated region) remains nearly unchanged during the flow boiling process in the heated region. The proposed MAGNETIC- boiling driven heat TRANSPORT device is usable in a closed circulating loop which can be extensively utilized in electronics cooling applications.

The present study investigates the structural, MAGNETIC, and electrical properties of non-stoichiometric LaMn1-xCuxO3 (x= 0, 0. 025, 0. 05, 0. 075, and 0. 125) ceramics. The results of X-ray diffraction refinement indicated that all samples were crystallized in an orthorhombic structure and no apparent crystal structure change was introduced by doping Cu up to x=0. 125. The FerroMAGNETIC (FM) nature revealed by non-stoichiometric LaMn1-xCuxO3- was verified through the appearance of ParaMAGNETIC-FerroMAGNETIC (PM-FM) transition temperatures in AC MAGNETIC susceptibility measurement of the samples. Due to the coexistence of AntiferroMAGNETIC (AFM) and FM phases, all samples contained Re-entrant Spin Glass (RSG) and Cluster Spin Glass (CSG) states. The results showed that FM phase was comparable or even dominant in the doped samples up to x=0. 075; however, after doping, AFM phase overcame the FM phase as a result of reduction of double exchange interaction. Temperature dependence of resistivity measurement indicated that upon increasing the Cu-doping level, resistivity decreased, except for the x=0. 125 sample, and that metal-insulator transition at low temperatures was detected in the doped samples. Furthermore, changing the MAGNETIC phase in the case of x=0. 125 sample from FM (in x=0. 075) to AFM dominant phase was accompanied by changing the TRANSPORT parameters obtained from small polaron hopping models.

The TRANSPORT properties of the Dirac fermions through the electric and MAGNETIC barriers on the surface of a 3D topological insulator with a hexagonal warping effect have been investigated using the transfer matrix method. It was found that the transmission probability and the electric conductance are strongly modulated by the gate voltage, incident energy, number of barriers, and the exchange field strength. It was remarkable that the Dirac fermion is not perfectly transmitted at the normal incidence, confirming the role of the proximity effect in the suppression of transmission for normal incident electrons. The MAGNETIC field can open up a band gap in the conductance spectrum at the Dirac point, depending on the magnetization orientation. The time-reversal symmetry remains broken as long as the magnetization orientations in modulated regions are not entirely parallel to the surface of a topological insulator. The resonant states and the position of resonant peaks are dependent on the gate voltage and incident energy values. It is shown that the number of tunneling resonances increases with increasing the number of barriers. The hexagonal warping effect can increase electronic TRANSPORT at high energies. The results found here are consistent with those obtained previously.