Permanent magnet direct current motor (PMDC) has been widely used in industrial, automotive, and home applications because of simple structures, advantage of price and easy controllability. However, brush contact resistance is difficult to measure if the DC motor is not disassembled. In this paper, Characteristics analysis and measurement of motor parameters are treated about PMDC motors. For analyzing this method, the parameter model is conducted to measure the brush contact resistance. Finally, analysis values are compared to test result to verify the method.

Recently, it was predicted that the quaternary Heusler compounds, RhTiYGe is half-metallic in bulk state by a first-principles calculation. In this study, we have investigated whether the half-metallicity is conserved or not at the (001) surfaces of RhTiYGe by means of the full-potential linearized augmented plane wave (FLAPW) method within the general gradient approximation. For this we considered two types of surface termination: RhTi-terminated and YGe-terminated (001) surfaces. From the calculated total magnetic moments and the local density of states of each atom, we found that half-metallicity is conserved for the YGe-terminated system, while the RhTi-terminated (001) surface is not half-metallic. The main contributions to the total magnetic moments of the two systems come from the Ti atoms, and the values of magnetic moments are in between 1.35 μ_B and 1.36 μ_B.

A giant magnetoresistive - spin valve (GMR-SV) NiFe/CoFe/Cu/CoFe/IrMn/Ta multilayer film was fabricated by ion beam deposition on a commercial high - temperature superconductor Y₁Ba₂Cu₃O_{7 − x} (YBCO) film. The thickness of the hybrid YBCO thin film was 300 nm and one of the antiferromagnetic IrMn-based GMR-SV thin film was 55 nm. The superconductor characteristics of the YBCO thin films were confirmed by the R-T curve measured with 4-terminal and the Q-T and I-V curves measured with a microwave cavity resonator. In particular, the phenomenon of negative magnetoresistance (MR) ratio in the reversed MR curve of −7.4% is explained by the current transfer effect from the MR and the I-V curves measured by the 2-, 3-, and 4-probe methods at 77 K below the critical temperature. It was also confirmed by SEM image that a gap layer of 9.3 nm was present between the YBCO film and the GMR-SV multilayer. The residual resistance of 0.456 Ω was measured due to the presence of the gap layer and the difference in current transfer was caused by the superconductor depending on the change of the spin magnetization array configuration of GMR-SV.

A CRDM (Control Rod Drive Mechanism) is an electromagnetic device which drives a control rod assembly linearly to regulate the reactivity of a nuclear core when electrical current is supplied to the lift and latch coils. Lifting force is decided according to magnetic substance properties, a gap between magnetic substances, and input electrical current in SMART CRDM design. In this paper, lifting force calculation according to gap and electrical input current variation of magnetic substance has been conducted by using finite element electromagnetic simulation. As a result, upper gap is large effect than bottom gap that the degree of contribution at the magnetic circuit. Also, it was confirmed that the larger the radial gap is the smaller the lifting force, and the larger input current is the larger lifting force. The results of this study are reflected in SMART CRDM design.

The Diffusion weighted image results in Nyquist ghost artifact (NGA) due to differences in magnetization susceptibility due to the anatomical structure, resulting in images with poor diagnostic value. In this paper, we have studied the reduction of NGA using the 2D navigator-based reacquisition readout segment (RS-EPI) technique in our own Phantom. In order to know the characteristics of NGA and its reduction method, single-shot EPI (SS-EPI) technique and RS-EPI technique changes the segment number, echo spacing, and bandwidth. Ghost - to - signal ratios (GSR) were measured in the presence of NGA. As a result, it was confirmed that the RS-EPI technology has a smaller NGA than the SS-EPI technology. The correlation results of the parameters of the RS-EPI technique, Increasing the number of segments reduces Bandwidth as a cause of increasing NGA. But the minimum value of echo spacing is reduced, NGA decreased when minimum value was selected.

In this study, the correlation between GeneRalized Autocalibrating Partial Parallel Acquisition acceleration factor and Readout segement interval Of Readout Segmentation Of Long Variable Echo trains Diffusion Weighted Image based on T1 tirm dark-fluid after contrast enhancement was analyzed. The changes of signal intensity according to contrast concentration were studied. In order to characterize signal intensity in Readout Segmentation Of Long Variable Echo trains Diffusion Weighted Image using Gadolinium contrast agents, Primovist and physiological saline solution were diluted with a 1.4 cm diameter cylindrical syringe at a total concentration of 3 mL of 0.05 cm/mL to 250 mmol/mL, and 32 ghost samples were prepared and analyzed for image data. Statistical analysis was performed using correlation analysis (Pearson correlation coefficient, SPSS version 22.0 (IBM Co., Armonk, NY, USA). The results were as follows. Increasing the readout segment increases the SNR and decreases the intensity of the contrast but increases the scan time. Therefore, we can minimize the effect of the GeneRalized Autocalibrating Partial Parallel Acquisition acceleration factor of the readout segment on the acquisition time and contrast by the increased SNR.

Energy product of magnets, especially permanent magnets, is often used without a clear understanding of its definition, even though it is a basic concept that is widely known to relevant industry workers and researchers. In this article, we introduce the definition of energy product from the energy stored in the field outside the magnet as well as the correct method to predict its maximum value (BH_max) from a magnetization hysteresis loop.