BiMnO₃ has been assumed to be a very rare example of multiferroic materials. But the growth of BiMnO₃ thin film with high quality itself was very challenging. So physical properties has been studied only marginally for this compound. Here we report the observation of resistance switching for twin free BiMnO₃ thin film which was grown with high quality on the miscut Nb-doped SrTiO₃ (110) substrate.

Features of melting heat transfer as well as homogeneous-heterogeneous reaction in thermally stratified stagnation flow of Eyring-Powell fluid along with heat generation/absorption effects are explored in this article. Fluid flow is examined over a sheet of variable thickness in the presence of stretching phenomena. Variable strength of magnetic field is considered normal to the flow field. Suitable transformations are introduced for the sake of conversion of partial differential equations to ordinary differential equations. Homotopic method is utilized to tackle highly nonlinear problem and series solutions are attained. Behaviors of relevant parameters are portrayed for velocity, thermal and concentration distributions. Graphical results reveal that the concentration profile enhances for higher Schmidt number while it exhibits recessive behavior for increment in homogeneous reaction parameter. Larger values of heterogeneous reaction parameter result in intensified concentration field. Velocity field declines as a result of increment in fluid parameters ε as well as δ*.

A performance moment integration method is proposed to accurately estimate the first two statistical moments, mean and variance, of electromagnetic performance functions in the present of uncertainties. To maximize computational efficiency, its numerical integration is executed not on the input design domain but on the output performance domain, where quadrature points are explored by the first order reliability analysis method. For better understating between statistical moment analysis methods, two different numerical integration schemes of dimension reduction method and performance moment integration method are compared with each other. Finally, a mathematical model and a loudspeaker design model are tested to demonstrate the features of two methods and to examine their numerical accuracy and efficiency.

The purpose of this study was to compare image quality between compressed sensitivity encoding (CS) and sensitivity encoding (SENSE) in single-shot turbo spin echo diffusion-weighted imaging (TSE-DWI). Signal-to-noise ratios (SNR), apparent diffusion coefficient (ADC) values, and geometric accuracies were measured with an American College of Radiology head phantom. CS showed a high mean SNR, less variation in ADC values, and reduced imaging acquisition time (21.7 %-39.3 %) compared with SENSE. In addition, there was no significant difference in geometric accuracy between SENSE and CS. In conclusion, in comparison with SENSE TSE-DWI, CS TSE-DWI resulted in a reduced imaging acquisition time and improved SNR, while maintaining image quality.

Diffusion-weighted imaging (DWI) is frequently used in the field of diagnostic medicine to detect various human diseases. In DWI, noise suppression is very important for achieving high detection accuracy of diseases. In this study, we develop a deep convolutional neural network (Deep-CNN) noise reduction algorithm and evaluate its effectiveness in DWI by performing both simulations and real experiments with a 1.5- and a 3.0-T MRI system. The results validate the proposed Deep-CNN algorithm for DWI. Compared with previously developed non-local means (NLM) algorithms, the proposed Deep-CNN algorithm achieves superior quantitative results. In conclusion, the quantitative results verify that the proposed Deep-CNN algorithm has higher noise reduction efficiency and image visibility than previously developed algorithms for DWI

This paper presents an accurate yet simple analytical model to predict the torque characteristics of an adjustable-speed permanent magnet eddy-current coupling in the low slip working area. Based on an improved magnetic equivalent circuit method, the flux density is quantitatively calculated, and then the general explicit expression of electromagnetic torque is developed. Moreover, the saturation effect of ferromagnetic materials and the restricted slip have been reasonably taken into account. Compared with the 3-D finite element analysis and measurement results, the validity of this model is confirmed. In addition, several important parameters of such devices are analyzed and discussed.

In this study, the effect of the material characteristics of electrical steel sheet on permanent magnet direct current (PMDC) motors is investigated using finite-element analysis. The motor design and test results are examined and verified through fabrication. The characterizations of brushless direct current (BLDC) motors according to the materials used in their cores have been actively studied. On the other hand, the effect of material characteristics on a PMDC motor consisting of brushes and commutators has not been studied as much. In the case of the PMDC motors, electrical steel sheets are infrequently used because this motor is relatively smaller than the BLDC motor. However, the iron loss characteristics, which are proportional to the frequency and the magnetic flux density, affect the efficiency even in small motors. Further, the output of the motor changes owing to saturation due to iron loss. The outcome presented in this study provides core materials selection guidelines to improve motor efficiency.

The self-suspension of magnet in magnetic fluid has been widely used in micromechanical systems, sensors, and dampers. The magnetic field associated with the ring magnet is obtained by numerical calculation and simulation through which the axial magnetic levitation force is calculated, and the numerical calculation, simulation, and experimental results agree with each other. The influence of the radial eccentricity of the ring magnet on the axial magnetic levitation force is studied, the ring magnet will experience a maximum axial magnetic levitation force without radial eccentricity. With the increase of radial eccentricity and the decrease of the distance between the bottom of the ring magnet and container, the axial magnetic levitation force will continue to decrease. But it is worth noting that the magnitude of the change caused by radial eccentricity is negligible compared to that of the axial magnetic levitation force.

Obesity usually occurs due to homeostasis and hedonic food intake behavior caused by plasticity variation in both cortical and subcortical brain structures. However, little volumetric analysis has been done to study the relationships between obesity and subcortical structures. For this study, we aimed to investigate the volumetric differences of subcortical structures between 21 obese patients and 10 healthy controls using high resolution 3T MRI T1-weighted scans. Obese patients showed reduced subcortical gray matter volume in right caudate and right nucleus accumbens and enlarged volume in right amygdala. Vertex-wise shape analysis of subcortical structures showed bilateral caudate alterations in obese patients. Moreover, the bilateral amygdala negatively correlated with increasing age in obese patients. In conclusion, we present data showing association between obesity and subcortical brain structures. Various studies have shown that morphological changes can cause functional modifications in the brain. Therefore, we believe our analysis of volumetric differences in subcortical structures could be helpful for identifying neurophysiological changes that occur in obese patients.

This paper studies magnetohydrodynamic (MHD) flow of Brinkman type nanofluids with the influence of heat generation, chemical reaction and thermal radiation. The f luid i s taken ov er a v ertical plate flat p assing through a porous medium. Four distinct types of nano particles (Cu, Ag, TiO₂ and Al₂O₃) are taken in a base fluid H₂O. The vertical plate with constant temperature is oscillating in its own plane. The flow is described by the partial deferential equations with suitable initial and boundary conditions. The Laplace transform method is used to obtain the exact solutions for velocity, temperature and concentration. These solutions are interpreted graphically using computational software Mathcad-15 to analyze the influence of embedded parameters such as Brinkman parameter, permeability of porous medium, chemical reaction parameter, nano particle volume fraction, heat generation parameter, magnetic parameter and radiation parameter. Skin-friction, Sherwood number and Nusselt number are calculated mathematically.

The hybrid nanofluids are novel nanofluids and can be made by adding different types of nanoparticles in the plain fluid. The mathematical modeling of hybrid nanofluid under the magnetic influence over a vertical wavy surface is developed in the present theoretical investigation. The analysis is performed for hybrid nanofluid consisting of Al₂O₃-SiO₂ nanoparticles and compared with SiO₂ nanoparticle. The theoretical results also indicate that Al₂O₃-SiO₂ water hybrid nanofluid have higher heat transfer rate when compared with SiO₂- water nanofluid. In hybrid nanofluid, the choice of a suitable mixture of nanoparticles can lead to desire heat transfer phenomena. The implicit finite difference scheme is utilized for solution purposes. Results are presented in tabular and graphical form for the choice of suitable parameters.

In this research, the behavior of the metal magnetic memory (MMM) signals near the artificial cracks located the back side of A572 specimens are tried. The materials are used as power transmission tower material. The variations of the MMM signals with the applied tensile loads are studied. It is found that both the tangential component, Hp(x), and the normal component, Hp(y), are effectively showed the stress concentration zone (SCZ) caused by discontinuities. The results of modeling and MMM technique showed that the loads create residual stress and lead to the change of magnetic field strength around artificial cracks in the specimen and that is relatively different from the crack free area. This research is useful for expending MMM method as a tool of nondestructive testing method for detecting subsurface flaws.

The purpose of this study was to investigate the changes in apparent diffusion coefficient of brain parenchymal tissue according to the number of application of b-values in diffusion weighted images. The diffusion weighted image was obtained from 13 subjects using 3.0 Tesla MRI scanner. At this time, each ADC map image was created after obtaining the image by dividing it into the method for applying b-values 0, 1,000 and b-values 0, 500, 1,000 and 1,500 respectively. To quantitatively compare the ADC values, two observers measured the mean ADC values by setting four ROIs in each white matter, gray matter, thalamus, globus pallidus in the ADC map images. The ADC values measured from the two methods were validated with statistical analysis tools. In the two imaging methods, the inter-observer reliability of the measured ADC values is analyzed by using the ICC, there was a good correlation and a significant difference in white matter, thalamus and the globus pallidus excluding gray matter (p < 0.05). Also, Mann Whitney U test are used to verify statistical Results of significance verification of ADC values changes in the intra-observer, Observers 1 were significant in all ROIs between the two methods (p < 0.05). Observers 2 were significant in the white matter, thalamus and globus pallidus (p < 0.05). However, Gray matter was unable to identify significant results (p > 0.05). As a results, the variation of the ADC values according to the number of applying of b-values in a brain parenchyma usually is statistically significant. So, since the ADC value of the brain parenchyma tissue is a relative value for various conditions, it is necessary to apply it considering the time required for imaging and the characteristics of the brain disease rather than necessarily applying a large number of b-value sampling.

Magnet therapy (MGTH) is a commonly used method in physical therapy. Therapeutic effect is achieved with device-created magnetic fields, which can be described with numerous parameters. The effect of the MGTH depends on the used parameters; therefore it is important to be familiar with them. There are 10 parameters which should be included in studies on biological tissues. Publication of all parameters in studies occurs rarely. We performed measurements of magnetic field parameters in three MGTH devices creating a pulsed electromagnetic field in three different manners - with a solenoid, with Helmholtz coils and with magnetic mattress. In this paper we have discussed and present the measurements of parameters and spatial distribution of MF which we need to be familiar with when applying MGTH.

The coexistence of fat and water in the human body causes difficulties in obtaining accurate images using magnetic resonance imaging (MRI). This study evaluated the usefulness of the spectral pre-saturation inversion recovery (SPIR) and short TI inversion recovery (STIR) pulse sequences in suppressing fat. MRI of a water-oil phantom was performed using an Ingenia 3.0-T scanner (Philips Medical Systems, Best, The Netherlands). For quantitative evaluation of the images, the plot profile, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were measured and compared using ImageJ program (NIH, Bethesda, MD, USA). The SNR for water was higher by 56.04 % on STIR (403.59) than on SPIR (258.64). The SNR for fat was higher by 52.10 % on STIR (17.34) than on SPIR (11.40). The CNR was higher by 24.87 % on STIR (308.75) than on SPIR (247.24). Compared to SPIR, the STIR pulse sequence showed a better fat clearing effect. Therefore, it is necessary to select the appropriate fat suppression method according to the clinical necessity.

This study examined the effects of Pulsed Electromagnetic Fields (PEMF) therapy on the expression of c-fos protein in rats with knee osteoarthritis (OA). The aim of this study was to compare the improvement of pain relief in two experimental groups: PEMF and treadmill exercise. Thirty-two male Sprague-Dawley rats were randomly divided into four groups with eight rats in each: CON1 (including rats sacrificed 1 day after OA induction), CON7 (including rat sacrificed 7 days after OA induction), PEMF (including rats with applied PEMF for 7 days after OA induction), TE (including rats with applied treadmill exercise for 7 days after OA induction). A statistically significant reduction on expression of c-fos was observed in TE and PEMF groups compared to that in CON7 group. However, there was no significant difference in expression of c-fos between the TE group and PEMF group. It is suggested that PEMF could have positive effect on pain relief for OA confirming reduction on expression of c-fos in the spinal cord.

There are quick temporary changes on brain cortex on Bax, c-Fos mRNA, and protein after brain damage and c-Fos is related to biological factors such as cell cycle process and tumorigenesis. After ischemic damage, c-Fos quickly causes initial gene and transcription factor on CA1 area, and continuous inducing of c-Fos cause apoptosis after ischemic damage. In this study, LC series resonant boost converter is used on a magnetic stimulation device. Transcranial Magnetic Stimulation (TMS) was used to determine effects of Magnetic stimulation on Bax, Caspase-3, immunoreactive cell on 12 and 24 hours ischemia induced with apoptosis on ischemia. To control the experimental device, EICS affiliate AE32000C Processor Core was used. After magnetic stimulation with TMS device on an ischemia mouse, we determined effects of magnetic stimulation on Bax and c-Fos on cerebellum. We want to identify a more positive approach to apoptosis caused by early ischemic brain injury than electrotherapy by examining c-Fos protein changed large brain neuron after stimulating ST 36 on an ischemic mouse’s brain.

This study was conducted to compare the effects of high frequency and low frequency transcutaneous electrical nerve stimulation applied to gastrocnemius muscle on proprioception, spasticity, and dynamic balance of stroke patients. Twenty subjects were randomly assigned to each of 10 experimental and control groups. High frequency transcutaneous electrical nerve stimulation was applied to the experimental group and low frequency transcutaneous electrical nerve stimulation was applied to the control group for 20 minutes per day, 5 times a week for a total of 4 weeks. The subjects were assessed for proprioception by joint position sense in ankle plantarflexion and dorsiflexion, spasticity was assessed using Modified Ashworth Scale (MAS) and amount of resistance, and dynamic balance was assessed using the Timed Up and Go (TUG) test. A significant improvement in joint position sense (plantarflexion, dorsiflexion), MAS, amount of resistance, and TUG was observed after intervention in the experimental group (p < 0.05), and there was a significant improvement in all evaluation items compared to the control group (p < 0.05). The results of this study suggest that application of high frequency transcutaneous electrical nerve stimulation to the bilateral gastrocnemius muscles of patients with stroke has a positive effect on proprioception, spasticity and dynamic balance.

Arrayed eddy current testing (AECT) has been widely applied in the field of crack detection, displacement measurement and many other fields due to its non-destructive and high efficiency. But the coupling interference of AECT exists objectively and leads to the detection error directly. In this paper, a magnetic shielding layer is proposed to reduce the coupling interference. The relationships between electromagnetic parameters of magnetic shielding material and coupled magnetic field are discussed theoretically. Furthermore, the simulation and experiments are carried out, the results are consistent. It shows that the application of magnetic shielding layer in AECT can reduce the mutual inductance of probe coils and increase the output voltage. Additionally, the most important factor to select material of magnetic shielding layer is the conductivity. Thus, the magnetic shielding layer with large conductivity will be suitable for AECT to promote the testing performance.

Amorphous materials have the advantages of high permeability and low core losses. Their application in the motor can reduce the energy consumption and improve the efficiency. To investigate the advantage of amorphous materials on the performance of permanent magnet synchronous motors (PMSMs) at lower speed situation, three 1.5 kW motors used in steering pumps of electric vehicles are analyzed and compared. Two prototypes and the experimental platform are built. The experimental results indicate that the efficiency of the PMSM motor with amorphous materials increases by 1.4 % at 1200 rpm, which shows that amorphous materials can also improve the motor performance at lower speed. To further take advantage of amorphous materials, the particle swarm optimization algorithm is used to optimize the dimensions of amorphous motor and the efficiency is increased by 0.54 %.

A dual-rotor switched reluctance motor is proposed in this paper. The structure and working principle of the motor are introduced in detail. The structural parameters have great influence on the performance of the motor, so sensitivity analysis of several important structural parameters to the output torque is carried out based on the two-dimensional finite element method, which improves the average torque of the rotor in the outer air gap. Additionally, the performance of the motor with various pole distributions is analyzed and compared. The results show that when the magnetic polarity distribution of the outer stator is NSNSNSNSNSNS and the magnetic polarity distribution of the inner rotor is NSNSNS, the motor has the best performance. The torque of the motor is compared with that of the traditional single-rotor switched reluctance motor. It shows that the performance of the motor proposed in this paper is better.

In this work, a compact tri-axis fluxgate magnetometer comprising a single magnetic core was implemented and the effectiveness of the orthogonality correction algorithm was demonstrated. The vector magnetometer consists of a tube-shaped soft magnetic flux chopper with a toroidal coil and three concentric pick-up coils. The tube-shaped flux chopper with magnet wires has the total dimension of 10 mm × 10 mm. The number of turns of the pick-up coils X-, Y-, and Z- are 110, 110 and 150, respectively. The center of flux chopper is also the geometric center of the three pick-up coils, of which the sensing directions are aligned along the Cartesian axes. The concentric design ensures a single field point for the three sensing axes. When using the tri-axis fluxgate magnetometer as an electronic compass, the geomagnetic field components converted from the demodulated outputs of the sensing coils shows high accuracy by using the voltage-to-field transfer matrix. The proposed fluxgate system is suitable for applications related to high-accuracy static magnetic field measurement, e.g. geomagnetic field monitoring, electronic compass, and magnetic field mapping.

Pulse width modulation (PWM) of voltage source inverter (VSI) is common for speed regulation of permanent magnet (PM) brushless direct-current (BLDC) motor drives. However, when the motor runs at high speed, the conventional PWM technique may become unfeasible due to the low carrier ratio of inverter, which makes the motor current distorted and the motor core loss increased significantly. In this paper, two control strategies, namely single pulse variable width (SPVW) and dual pulses variable width (DPVW), are introduced for the high-speed PM BLDC motor drives, and are comprehensively investigated. Finite element method (FEM) is employed to evaluate and compare the drive system performance when using the conventional PWM, and the proposed SPVW and DPVW, respectively. Influence of the control techniques, especially on the loss distribution, is revealed.

In this paper, the characteristics of the electromagnetic field using FEM are analyzed for the PMSG basic model, and the optimized design is performed to improve the performance of the generator. In the case of the SPM type 5 kW generator used in this paper, the torque ripple level was analyzed to be relatively high compared with the load torque generated during operation. Therefore, shape design was performed to reduce it, and permanent magnet shape was selected as design variables. Particularly, the characteristics of permanent magnet attached to the rotor surface by segment type and magnet tapering were compared. As a result, reduction in torque ripple and cogging torque was confirmed through the design of the shape of the permanent magnet. Also, the influence of the change of torque ripple and cogging torque on the vibration characteristics was studied. The vibration characteristics of the basic model and the improvement model were compared and analyzed based on the electromagnetic characteristics data. Simulation data shows that the amplitude of vibration is reduced in the improved model.