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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Magnetics
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Journal DOI :
The Korean Magnetics Society
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Volume & Issues
Volume 21, Issue 3 - Sep 2016
Volume 21, Issue 2 - Jun 2016
Volume 21, Issue 1 - Mar 2016
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The Half-metallic Properties of (001) and (110) Surfaces of CsSe from the First-principles
Bialek, Beata ; Lee, Jae Il ;
Journal of Magnetics, volume 21, issue 1, 2016, Pages 1~5
DOI : 10.4283/JMAG.2016.21.1.001
We investigated the half-metallicity and magnetism at the (001) and (110) surfaces of CsSe in cesium chloride and zinc-blende structures by using the all-electron full-potential linearized augmented plane wave method within the generalized gradient approximation. From the calculated local density of states, we found that all the surfaces preserve the half-metallicity of the bulk structures. The surfaces with a greater polarity have stronger ferromagnetic properties when terminated with Se atoms; the non-polar surfaces do not change their electronic or magnetic properties considerably as compared with the bulk structures.
Periodicity Dependence of Magnetic Anisotropy and Magnetization of FeCo Heterostructure
Kim, Miyoung ;
Journal of Magnetics, volume 21, issue 1, 2016, Pages 6~11
DOI : 10.4283/JMAG.2016.21.1.006
The magnetic anisotropy energy (MAE) and the saturation magnetization
heterostructures with n
Effects of Precipitate Element Addition on Microstructure and Magnetic Properties in Magnetostrictive Fe
Li, Jiheng ; Yuan, Chao ; Zhang, Wenlan ; Bao, Xiaoqian ; Gao, Xuexu ;
Journal of Magnetics, volume 21, issue 1, 2016, Pages 12~19
DOI : 10.4283/JMAG.2016.21.1.012
The <100> oriented
alloys with various contents of NbC or B were prepared by directionally solidification method at the growth rate of
. With a small amount of precipitates, the columnar grains grew with cellular mode during directional solidification process, while like-dendrite mode of grains growth was observed in the alloys with higher contents of 0.5 at% due to the dragging effect of precipitates on the boundaries. The NbC precipitates disperse both inside grains and along the boundaries of
alloys with NbC addition, and the Fe2B secondary phase particles preferentially distribute along the grain boundaries in B-doped alloys. Precipitates could affect grain growth and improved the <100> orientation during directional solidification process. Small amount of precipitate element addition slightly increased the magnetostrictive strain, and a high value of 335 ppm under pre-stress of 15 MPa was achieved in the alloys with 0.1 at% NbC. Despite the fact that the effect on magnetic induction density of small amount of precipitates could be negligible, the coercivity markedly increased with addition of precipitate element for
alloy due to the retarded domain motion resulted by precipitates.
Magnetic Properties of Helicobacter Pylori Ferritins Genetically Prepared Under Different Biomineralization Conditions
Son, K. ; Park, J.N. ; Yoon, Sungwon ; Suh, B.J. ; Cho, K.J. ; Kim, K.H. ; Jang, Z.H. ;
Journal of Magnetics, volume 21, issue 1, 2016, Pages 20~24
DOI : 10.4283/JMAG.2016.21.1.020
Magnetic properties of bio-magnetic molecule ferritin have been investigated. Two ferritin samples were synthesized under different magnetic fields, 0 and 9.4 T, respectively. This work is focused on the influence of magnetic field on biomineralization process. While magnetization vs. temperature (M-T) data of both samples measured at 1000 Oe are almost identical except for low temperature region (T < 6 K), magnetization vs. field (M-H) data show noticeable difference. From an analysis of M-H data by using a modified Langevin function, we could extract the saturation magnetization
(T), the effective magnetic moment
(T) and the linear susceptibility x(T). The difference between the samples is most prominent in the x(T), whereby the x(T) of the sample prepared at 9.4 T is 1.7 times bigger than that of the other. In addition, from hysteresis and relaxation measurements, we found the sample prepared at 9.4 T showed strikingly smaller coercivity and slower relaxation.
Effect of Deformation Temperature on Crystal Texture Formation in Hot Deformed Nanocrystalline SmCo
Ma, Q. ; Yue, M. ; Lv, W.C. ; Zhang, H.G. ; Yuan, X.K. ; Zhang, D.T. ; Zhang, X.F. ; Zhang, J.X. ; Gao, X.X. ;
Journal of Magnetics, volume 21, issue 1, 2016, Pages 25~28
DOI : 10.4283/JMAG.2016.21.1.025
In the present study, bulk anisotropic nanocrystalline
magnets were prepared by hot deformation. The effect of deformation temperature on the texture and magnetic properties are presented, based on which the mechanism of plastic deformation and texture formation during the hot deformation process is discussed. Our analyses reveal that deformation temperature is one of the most important parameters that determine the texture of
grains. We suggest that diffusion creep plastic deformation occurs during hot deformation, which is very sensitive to the energy gain provided by an increase in temperature.
Magnetic Properties and Impedance Spectroscopic Studies of Multiferroic Bi
Thang, Dao Viet ; Thao, Du Thi Xuan ; Minh, Nguyen Van ;
Journal of Magnetics, volume 21, issue 1, 2016, Pages 29~34
DOI : 10.4283/JMAG.2016.21.1.029
materials were synthesized via a sol-gel method. The crystal structure, magnetic properties, and complex impedance spectroscopy of multiferroic
(BNFO) materials were investigated by X-ray diffraction (XRD), Raman scattering, vibrating sample magnetometer (VSM), and complex impedance spectroscopy. Our results show that the lattice crystal constants (a, c) and the ratio c/a of BNFO materials decreased with increasing Nd concentration. All samples exhibited weak ferromagnetism at room temperature, and the magnetization of samples was enhanced by the presence of
ions. There was an enhancement in the spontaneous magnetization of BFO with increasing Nd concentration, which is attributable to the collapse of the spin cycloid structure.
Amorphous Cr-Ti Texture-inducing Layer Underlying (002) Textured bcc-Cr alloy Seed Layer for FePt-C Based Heat-assisted Magnetic Recording Media
Jeon, Seong-Jae ; Hinata, Shintaro ; Saito, Shin ;
Journal of Magnetics, volume 21, issue 1, 2016, Pages 35~39
DOI : 10.4283/JMAG.2016.21.1.035
amorphous texture-inducing layers (TIL) were investigated to realize highly (002) oriented
FePt-C granular films through hetero-epitaxial growth on the (002) textured bcc-
seed layer (bcc-SL). As-deposited TILs showed the amorphous phase in Ti content of
. Particularly, films with
kept the amorphous phase against the heat treatment over
. It was found that preference of the crystallographic texture for bcc-SLs is directly affected by the structural phase of TILs. (002) crystallographic texture was realized in bcc-SLs deposited on the amorphous TILs (
), whereas (110) texture was formed in bcc-SLs overlying on crystalline TILs (x < 30 and x > 70). Correlation between the angular distribution of (002) crystal orientation of bcc-SL evaluated by full width at half maximum of (002) diffraction (FWHM) and a grain diameter of bcc-SL indicated that while the development of the lateral growth for bcc-SL grain reduces FWHM, crystallization of amorphous TILs hinders FWHM.
FePt-C granular films were fabricated under the substrate heating process over
with having different FWHM of bcc-SL. Hysteresis loops showed that squareness (
) of the films increased from 0.87 to 0.95 when FWHM of bcc-SL decreased from
. It is suggested that the reduction of (002) FWHM affects to the overlying MgO film as well as FePt-C granular film by means of the hetero-epitaxial growth.
Nickel Substitution Effects on Nano-sized Co, Mn and MnZn Ferrites Synthesized by Sol-gel Method
Choi, Won-Ok ; Kwon, Woo Hyun ; Chae, Kwang Pyo ; Lee, Young Bae ;
Journal of Magnetics, volume 21, issue 1, 2016, Pages 40~45
DOI : 10.4283/JMAG.2016.21.1.040
Nickel substituted nano-sized ferrite powders,
), were fabricated using a sol-gel method, and their crystallographic and magnetic properties were subsequently compared. The lattice constants decreased as quantity of nickel substitution increased, while the particle size decreased in
ferrite but increased for the
ferrites. For the
) ferrite powders, the
spectra could be fitted as the superposition of two Zeeman sextets due to the tetrahedral and octahedral sites of the
ions. However, the
consisted of two Zeeman sextets and one single quadrupole doublet due to the ferrimagnetic and paramagnetic behavior. The area ratio of the
spectra could be used to determine the cation distribution equation, and we also explain the variation in the
parameters by using this cation distribution equation, the superexchange interaction and the particle size. The saturation magnetization decreased in the
ferrites but increased in the
ferrite with nickel substitution. The coercivity decreased in the
ferrites but increased in the
ferrite with nickel substitution. These variations could thus be explained by using the site distribution equations, particle sizes and spin magnetic moments of the substituted ions.
Photocatalytic Degradation of Oxytetracycline Using Co-precipitation Method Prepared Fe
Jia, Yuefa ; Liu, Chunli ; Li, Rong ;
Journal of Magnetics, volume 21, issue 1, 2016, Pages 46~50
DOI : 10.4283/JMAG.2016.21.1.046
nanocomposite were successfully synthesized by co-precipitation method using
as raw materials. Structural and textural features of the mixed oxide samples were characterized by X-ray diffractometer, field emission scanning electron microscopy and energy-dispersive X-ray. The effects of initial concentration of oxytetracycline (OTC), different competitive ions and organics on the photocatalytic degradation rate of OTC by the
nanocomposite were analyzed under UV and visible light irradiation. The results indicate that the optimized initial concentration of OTC was 50 mg/L to achieve the best photocatalytic efficiency.
and EDTA in the aqueous suspension were found to suppress the degradation rate of OTC, whereas the effect of
can be ignored.
Effect of Grain Boundary Modification on the Microstructure and Magnetic Properties of HDDR-treated Nd-Fe-B Powders
Liu, Shu ; Kang, Nam-Hyun ; Yu, Ji-Hun ; Kwon, Hae-Woong ; Lee, Jung-Goo ;
Journal of Magnetics, volume 21, issue 1, 2016, Pages 51~56
DOI : 10.4283/JMAG.2016.21.1.051
The microstructure and magnetic properties of HDDR-treated powders after grain boundary diffusion process (GBDP) with Nd-Cu alloy at different temperatures have been studied. The variation of GBDP temperature had multifaceted influences on the HDDR-treated powders involving the microstructure, phase composition and magnetic performance. An enhanced coercivity of 16.9 kOe was obtained after GBDP at
, due to the modified grain boundary with fine and continuous Nd-rich phase. However, GBDP at lower or higher temperature resulted in poor magnetic properties because of insufficient microstructural modification. Especially, the residual hydrogen induced phenomenon during GBDP strongly depended on the GBDP temperature.
Detection of Corrosion and Wall Thinning in Carbon Steel Pipe Covered With Insulation Using Pulsed Eddy Current
Park, Duck-Gun ; Kishore, M.B. ; Kim, J.Y. ; Jacobs, L.J. ; Lee, D.H. ;
Journal of Magnetics, volume 21, issue 1, 2016, Pages 57~60
DOI : 10.4283/JMAG.2016.21.1.057
Non Destructive Testing (NDT) methods that are capable of detecting the wall thinning and defects through insulation and cladding sheets are necessary. In this study we developed a Pulsed Eddy Current (PEC) system to detect wall thinning of ferro magnetic steel pipes covered with 95 mm thick fiber glass thermal insulator and shielded with aluminum plate of thickness 0.4 mm. In order to confirm the thickness change due to wall thinning, two different sensors, a hall sensor and a search coil sensor were used as a detecting element. In both the cases, the experimental data indicates a considerable change in the detected pulse corresponding to the change in sample thickness. The thickness of the tube was made to change such as 2.5 mm, 5 mm and 8 mm from the inner surface to simulate wall thinning. Fast Fourier Transform (FFT) was calculated using window approach and the results were summarized which shows a clear identification of thickness change in the test specimen by comparing the magnitude spectra.
Preparation and Electromagnetic Properties of an Electromagnetic Wave Absorber
Sun, Chang ; Sun, Kangning ; Pang, Laixue ; Liu, Jian ;
Journal of Magnetics, volume 21, issue 1, 2016, Pages 61~64
DOI : 10.4283/JMAG.2016.21.1.061
In this study, we report the as-prepared MgO-doped
, which was prepared by calcination technique and high-energy ball milling process, as an electromagnetic wave absorber. The phase analysis of
and the as-prepared MgO-doped
was detected utilizing X-ray Diffractometer (XRD). The microstructure was characterized using Scanning Electron Microscope (SEM). By means of the transmission/reflection coaxial line method, the electromagnetic properties and microwave absorbing properties of the as-prepared electromagnetic wave absorber were studied. It is found that the electromagnetic wave absorber has a minimum reflection loss value of -41 dB at 4.27 GHz with a matching thickness of 2.6 mm. The experiment results revealed that the as-prepared electromagnetic wave absorber could find potential applications in many military as well as commercial industries.
Novel Design and Research for a High-retaining-force, Bi-directional, Electromagnetic Valve Actuator with Double-layer Permanent Magnets
You, Jiaxin ; Zhang, Kun ; Zhu, Zhengwei ; Liang, Huimin ;
Journal of Magnetics, volume 21, issue 1, 2016, Pages 65~71
DOI : 10.4283/JMAG.2016.21.1.065
To increase the retaining force, a novel design for a concentric, bi-directional, electromagnetic valve actuator that contains double-layer permanent magnets is presented in this paper. To analyze the retaining-force change caused by the magnets, an equivalent magnetic circuit (EMC) model is established, while the EMC circuit of a double-layer permanent-magnet valve actuator (DLMVA) is also designed. Based on a 3D finite element method (FEM), the calculation model is built for the optimization of the key DLMVA parameters, and the valve-actuator optimization results are adopted for the improvement of the DLMVA design. A prototype actuator is manufactured, and the corresponding test results show that the actuator satisfies the requirements of a high retaining force under a volume limitation; furthermore, the design of the permanent magnets in the DLMVA allow for the attainment of both a high initial output force and a retaining force of more than 100 N.
Optimal Design for Thrust Ripple Reduction of Stationary Distributed-Armature System
Park, Eui-Jong ; Jung, Sang-Yong ; Cho, Kyoung-Pil ; Kim, Yong-Jae ;
Journal of Magnetics, volume 21, issue 1, 2016, Pages 72~77
DOI : 10.4283/JMAG.2016.21.1.072
Although the initial cost of permanent-magnet linear synchronous motors is high owing to the installation of armatures over the full length of the transportation lines, linear motors are useful for transportation systems because of their high speed, acceleration, and deceleration. For these reasons, research into reducing the cost of linear motors is necessary, and a stationary distributed-armature system has been suggested for installing armatures in sections where acceleration and deceleration of the mover are required. However, each armature has ends that significantly increase the cogging force, resulting in the increase in the thrust ripple of the mover. Therefore, in order to improve the thrust ripple of the system, the present study aims to provide auxiliary teeth on both ends of the armature to achieve an optimal design through an analysis of the contribution ratio with respect to factors regarding the design of the experiment and the objective function.
Effect of Slot Opening on the Cogging Torque of Fractional-Slot Concentrated Winding Permanent Magnet Brushless DC Motor
Yan, Jianhu ; Zhang, Qiongfang ; Feng, Yi ;
Journal of Magnetics, volume 21, issue 1, 2016, Pages 78~82
DOI : 10.4283/JMAG.2016.21.1.078
Cogging torque will affect the performance of a permanent magnet Brushless DC Motor (BLDCM), thus the reduction of cogging torque is key for BLDCM optimization. In this paper, the phase shifting of cogging torque for a fractional-slot concentrated winding BLDCM is analyzed using the Maxwell tensor method. Moreover, a 9-slot 10-pole concentrated winding BLDCM driven by ideal square waveform is studied with the finite element method (FEM). An effective method to reduce the cogging torque is obtained by adjusting the slot opening. In addition, the influences of different slot openings on back electromotive force (back-EMF), air gap flux density and flux linkage are investigated and experimentally validated using the prototype BLDCM.
Multilevel Inverters Power Topologies and Voltage Quality: A Literature Review
Rehaoulia, Abir ; Rehaoulia, Habib ; Fnaiech, Farhat ;
Journal of Magnetics, volume 21, issue 1, 2016, Pages 83~93
DOI : 10.4283/JMAG.2016.21.1.083
Due to their performances and inherent benefits, especially in medium-voltage and high-power applications, multilevel inverters have received an increasing attention in real world industrial applications. The present paper deals with a review of the main multilevel inverter topologies as well their most common derived and hybrid structures quoted in previous research works. It also encompasses an investigation on voltage harmonic elimination and THD estimation. For that reason, the paper summarizes the most relevant modulation techniques used so far to enhance the output voltage quality. Theoretical formulas evoked in the literature, for calculating the output voltage THD upper and lower bounds are reported and verified by adequate simulations.
Analysis of an Interior Permanent-Magnet Machines with an Axial Overhang Structure based on Lumped Magnetic Circuit Model
Seo, Jangho ; Seo, Jung-Moo ;
Journal of Magnetics, volume 21, issue 1, 2016, Pages 94~101
DOI : 10.4283/JMAG.2016.21.1.094
This paper shows a new magnetic field analysis of an interior permanent magnet (IPM) machines with an axial overhang structure wherein the rotor axial length exceeds that of the stator. The rotor overhang used to increase torque density of the radial flux machine is difficult to analyze because of extra consideration of axial direction, and thus it is general for machine designer to take 3-D finite element analysis (FEA) capable of considering both radial and axial complicated geometry in the machine. However, it requires too much computing time for preliminary design especially for optimization process. Therefore, in this paper a 2-D analytic method using a lumped magnetic circuit model (LMCM) is proposed to overcome the problem. For the analysis of overhang effect, the magnetic circuit is separated and solved from overhang and non-overhang regions respectively. For the validation of proposed concept, 3-D finite element analysis (FEA) is performed. From the analysis results, it is shown that our new proposed method presents good performance in terms of calculating electromotive force (EMF) and torque within a short time. Therefore, the proposed model can be useful in design of IPM with an overhang structure.
New Experimental Investigation of Magnetic and Electric Fields in the Vicinity of High-Voltage Power Lines
Ghnimi, Said ; Rajhi, Adnen ; Gharsallah, Ali ;
Journal of Magnetics, volume 21, issue 1, 2016, Pages 102~109
DOI : 10.4283/JMAG.2016.21.1.102
In this paper, the theoretical and experimental characteristics of magnetic and electric fields in the vicinity of high voltage lines are investigated. To realize these measurements and calculations, we have developed some equations for two overhead power line configurations of 150 kV (single circuit, double circuit), based on Biot-savart law, image and Maxwell theories, in order to calculate the magnetic and electric fields. The measurements were done to a maximum distance from the tower of 50 m, at a height of 1m from the ground. These experiments take into consideration the real situations of the power lines and associated equipment. The experimental results obtained are near to that of the Biot-Savart theoretical results for a far distance from the tower; and for a distance close to the power line, the results from the image theory are in good agreement with the experimental results.
Parametric Analysis of Tubular-Type Linear Magnetic Couplings with Halbach Array Magnetized Permanent Magnet by Using Analytical Force Calculation
Kim, Chang-Woo ; Choi, Jang-Young ;
Journal of Magnetics, volume 21, issue 1, 2016, Pages 110~114
DOI : 10.4283/JMAG.2016.21.1.110
Magnetic couplings are widely used in various industrial applications because they can transmit magnetic force without any mechanical contact. In addition, linear couplings have many advantages. For example, they do not need to convert rotary motion to linear motion. This paper shows an analytical analysis of tubular type linear magnetic couplings (TLMCs) with a Halbach array magnetized permanent magnet (PM). An analytical method for magnetic fields owing to PMs is performed by using magnetic vector potential as well as Poisson and Laplace equations. Then, the magnetic force is calculated by using the Maxwell stress tensor. The analytical analysis results were compared with finite element method (FEM) results. In addition, we predicted the magnetic force characteristic according to design parameters such as the iron core thickness, inner PM thickness to -outer PM thickness ratio, PM segment ratio of the axial magnetized PM segment and radial magnetized PM segment, and various pole numbers.
Effects of Contrast Agent Concentration on the Signal Intensity and Turbo Factor of TSE and Slice-selective IR in T1-weighted Contrast Imaging
Han, Yong Soo ; Lee, Soo Chul ; Lee, Dong Yong ; Choi, Jiwon ; Lee, Jong Woong ; Kweon, Dae Cheol ;
Journal of Magnetics, volume 21, issue 1, 2016, Pages 115~124
DOI : 10.4283/JMAG.2016.21.1.115
The present study analyzes T1 TSE and T1 slice sel. IR (dark_fluid) signal strength according to the degree of gadolinium contrast agent dilution and analyzes the turbo factors with regard to changes in the maximum and overall signal strength to study correlations between changes and signal-to-noise ratios (SNRs) and compare peak-to-peak SNR (PSNR) enhancement in order to improve the quality of T1-weighted images. Enhancement TR (600 msec) evaluated to determine the T1 TSE turbo factor and obtain the maximum signal strength, T1WI were used sequentially to experiment with turbo factors_1-4. T1 slice sel. IR (dark-fluid) was used to sequentially test turbo factors_2-5 but not turbo factor_1 at a TR (1500 msec) and compare data at an increase in T1 of 900 msec. The T1 TSE was reduced according to the contrast agent concentration. Phantom signal strength increased, whereas turbo factors_1-4 exhibited maximum signal strength at a concentration of 3 mmol, followed by a gradual decrease. In the turbo factors_2-5, the signal strength increased sharply to maximum signal strength at 0.7 mmol, followed by a reduction. T1 TSE had a greater maximum signal strength than did T1 slice sel. IR (dark_fluid). A comparison of SNR found that T1 TSE imaging was superior (33.3 dB) in turbo factor_1 and T1 slice sel. IR (dark_fluid) was highest (33.9 dB) at turbo factor_5. A PSNR comparison analysis was not sufficient to distinguish between the images obtained with both techniques at 30 dB or higher under all experimental conditions.
Buffer-Optimized High Gradient Magnetic Separation: Target Cell Capture Efficiency is Predicted by Linear Bead-Capture Theory
Waseem, Shahid ; Udomsangpetch, Rachanee ; Bhakdi, Sebastian C. ;
Journal of Magnetics, volume 21, issue 1, 2016, Pages 125~132
DOI : 10.4283/JMAG.2016.21.1.125
High gradient magnetic separation (HGMS) is the most commonly used magnetic cell separation technique in biomedical science. However, parameters determining target cell capture efficiencies in HGMS are still not well understood. This limitation leads to loss of information and resources. The present study develops a bead-capture theory to predict capture efficiencies in HGMS. The theory is tested with CD3- and CD14-positive cells in combination with paramagnetic beads of different sizes and a generic immunomagnetic separation system. Data depict a linear relationship between normalized capture efficiency and the bead concentration. In addition, it is shown that key biological functions of target cells are not affected for all bead sizes and concentrations used. In summary, linear bead-capture theory predicts capture efficiency (
) in a highly significant manner.
The Effects of Nonmagnetic Bolus on Contralateral Breast Skin Dose during Tangential Breast Irradiation Therapy
Won, Young-Jin ; Cho, Jae-Hwan ; Kim, Sung-chul ;
Journal of Magnetics, volume 21, issue 1, 2016, Pages 133~140
DOI : 10.4283/JMAG.2016.21.1.133
In this study the contralateral breast skin dose was decreased. It was to apply the results to the clinical study after analysis of different radiation dose amounts to contralateral breast with nonmagnetic bolus and without nonmagnetic bolus. A Rando phantom was computed tomography (CT) simulated, five treatment plans were generated: open tangents, open field in field, wedge 15, wedge 30, and intensity-modulated radiotherapy (IMRT) plan with 50.4 Gy to cover sufficient breast tissue. Contralateral breast skin dose was measured at 8 points using a glass dosimeter. The average contralateral breast dose using nonmagnetic bolus showed better excellence in decreasing the absorbed dose in the order of
cGy (49%), and
cGy (64%) than changing the treatment plan. This study focused on decreasing the effect of scattered dose by use of a nonmagnetic bolus on the contralateral breast during radiotherapy in breast cancer patients and an intriguingly significant decrease was observed parallel to the opposed beam.
The Effect of Rotating Magnetic Field on Enterotoxin Genes Expression in Staphylococcus Aureus Strains
Fijalkowski, Karol ; Peitler, Dorota ; Zywicka, Anna ; Rakoczy, Rafal ;
Journal of Magnetics, volume 21, issue 1, 2016, Pages 141~147
DOI : 10.4283/JMAG.2016.21.1.141
Staphylococcus aureus cultures exposed to rotating magnetic field (RMF) were studied in order to analyse the possible induced changes in staphylococcal enterotoxin genes (se) expression. Liquid cultures of S. aureus strains carrying different se were exposed to the RMF of magnetic frequency 50 Hz and magnetic induction 34 mT for 10 h at
. Three time points of bacterial growth cycle were considered for RNA extractions. Gene expression analyses were evaluated using real-time quantitative PCR method. The present study confirmed, that the RMF can stimulate the growth rate of S. aureus cultures in comparison to the unexposed controls, while the stimulation is not strain dependent. The studies have also shown, that the RMF, depending on the exposure time but regardless the bacterial strain, can influence on the expression of various se. In general, except for sea, as a result of bacterial exposure to the RMF through subsequent growth phases, the expression of se decreased, reaching the values below results recorded for unexposed controls. In the case of sea expression remained at a lower level as compared to the control, regardless the time of exposition.
Evaluation of Modified Turbo Spin Echo Technique Compared with Double Inversion Recovery Technique in Acquisition of Black Blood Brain Vessel Image
Choi, Kwan-Woo ; Lee, Ho-Beom ; Na, Sa-Ra ; Son, Soon-Yong ;
Journal of Magnetics, volume 21, issue 1, 2016, Pages 148~152
DOI : 10.4283/JMAG.2016.21.1.148
The main goal was to evaluate effectiveness of a modified TSE sequence compared with DIR (double inversion recovery) sequence in acquisition of fast flow brain vessel images using signal void effect. 32 healthy volunteers (10 men and 22 women; mean age of 31 years; ranging between 28-43 years) who underwent black blood DIR sequence (group A) and the modified TSE sequence (group B) were enrolled in our study. Signal to Noise Ratio (SNR) and Contrast to Noise Ratio (CNR) of the internal carotid arteries` lumen were compared in T1 and T2 weighted images for both group A and B. The images obtained from group B showed lower SNR values in internal carotid artery than the group A in both of the T1 and T2 weighted images (11.49% and 13.66% respectively). While the CNR values were higher in the group B than the group A in both of the T1 and T2 weighted images (8.69% and 7.55 % respectively). The qualitative score of all categories were not significantly different between the two groups. Furthermore approximately 49% of the total scan time was reduced from group B. Our study is to shorten the scanning time and minimize the inconveniences of the patients in acquisition of the black blood images of brain by using the signal void effect in the modified TSE technique while keeping the diagnostic value of the test.
Non Darcy Mixed Convection Flow of Magnetic Fluid over a Permeable Stretching Sheet with Ohmic Dissipation
Zeeshan, A. ; Majeed, A. ;
Journal of Magnetics, volume 21, issue 1, 2016, Pages 153~158
DOI : 10.4283/JMAG.2016.21.1.153
This paper aims to discuss the Non Darcy boundary layer flow of non-conducting viscous fluid with magnetic ferroparticles over a permeable linearly stretching surface with ohmic dissipation and mixed convective heat transfer. A magnetic dipole is applied "a" distance below the surface of stretching sheet. The governing equations are modeled. Similarity transformation is used to convert the system of partial differential equations to a system of non-linear but ordinary differential equations. The ODEs are solved numerically. The effects of sundry parameters on the flow properties like velocity, pressure, skin-friction coefficient and Nusselt number are presented. It is deduced the frictional resistance of Lorentz force decreases with stronger electric field and the trend reverses for temperature. Skin friction coefficient increase with increase in ferromagnetic interaction parameter. Whereas, Nusselt number decrease.