• Journal of the Korean Magnetics Society
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• v.4 no.4
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• pp.335-339
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• 1994

The crystallograpic and magnetic properties of $Eu(Fe_{1-x}In_{x})O_{3}$ (x=0, 0.03과 0.05) have been studied by the methods of X-ray diffraction, $M\"{o}ssbauer$ spectroscopy, and magnetic hysteresis measurement at room temperature. The X-ray results show that the samples have a crystal structure of orthorhombic and unit cell volume of the crystal with the exception of the sample of x=0 increases as increasing the In concentration. In the analysis assuming two sets of six-line of $M\"{o}ssbauer$ spectra, it is found that the magnetic hyperfine field in each of sets decreases increasing x. The linewidth of the absorption lines for the samples increased as increasing x. This implies that the data involve a sum of several hyperfine patterns which have intensity being proportional to $_{n}P_{z}(x)$, the probability of an environment with z such Fe neighbors. The magnetic hysteresis curves show decrease of $M_{s}$ and increase of $H_{c}$ of the samples with increasing x.

• Proceedings of the KOSOMBE Conference
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• v.1993 no.11
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• pp.63-66
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• 1993

Localized NMR spectra were obtained from phantom by OSIRIS technique. The selected volume, which can be controlled by frequency and its bandwidth, was 0.125cc out of 25cc and free of contamination from outer volume. With this technique NMR spectrum of a living tissue can be obtained without biopsy. i.e. in vivo state in which the metabolism of tissue may be quite different from in in vitro state. It is expected of this technique to be useful in the study of metabolism of living tissue as well as in diagnosis of deseases.

• Investigative Magnetic Resonance Imaging
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• v.12 no.2
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• pp.107-114
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• 2008

Purpose : The aim of this study is to determine possibility of application of in vivo proton ($^1H$) magnetic resonance spectroscopy (MRS) in distinguishing cystic mass arising around pancreas by comparison of in vivo MRS, in vitro MRS using 3T MR machine, based on nuclear magnetic resonance (NMR). Materials and Methods : We obtained spectra of in vivo MRS, in vitro MRS and NMR from abdominal mass arising around pancreas (mucinous cystic neoplasm=5, intraductal papillary mucin producing tumor=5, pseudocyst=1, and lymphangioma=1). We estimated existence of peak of in vivo MRS, and in vitro MRS concordant to that of NMR. We also evaluated differential peak for predicting specific disease. Results : Correlation of presence of peak with NMR showed showed sensitivity of 29.6%, specificity of 82.6% and accuracy of 67.7% on in vivo MRS (p = 0.096, McNemar test), sensitivity of 57.1% and specificity of 92.6% and accuracy of 82.3% on in vitro MRS (p = 0.362, McNemar test). The spectra of NMR for IPMT showed more frequent peaks at 3.5-4.0 ppm (p=0.026). Conclusion : Although chemical analysis, using NMR could be regarded as possible tool to differentiate cystic masses, in vivo and in vitro MRS need further technical evolution for clinical application.

• Radiation Oncology Journal
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• v.9 no.1
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• pp.1-6
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• 1991

The effect of 2-deoxy-d-glucose (2-DDG) on $C_3H$ mouse fibrosarcoma(FSall) was studied. Metabolic status, especially for energy metabolism, was studied using in vivo $^{31}P$-MRS, proliferative capacity was observed on flow cytometry(FC) and growth rate was measured after transplantation of $10^6$ viable tumor cells in the dorsum of foot of $C_3Hf/Sed$ mice. One gram of 2-DDG Per kg of body weight was injected intraperitoneally on 12th day of implantation. Average tumor size on 12th day of implantion was $250mm^3$. Growth rate of Fsall tumor was measured by tumor doubling time and slope on semilog plot. After 2-DDG injection, growth rate slowed down. Tumor doubling time between tumor age 5-12 days was 0.84 days with slope 0.828 and tumor doubling time between tumor age 13-28 days was 3.2 days with slope 0.218 in control group. After 2-DDG injection, tumor doubling time was elongated to 5.1 days with slope 0.136. The effect of 2-DDG studied in vivo $^{31}P$-MRS suggested that the increase of phosphomonoester (PME) and inorganic phosphate (Pi) by increasing size of tumor, slowed down after 2-DDG injection. Flow cytometry showed significantly increased S-phase and $G_2+M$ phase fraction suggesting increased proliferative capacity of tumor cells in the presence of 2-DDG. Authors observed an interesting effect of 2-DDG on FSall tumor and attempt to utilize as an adjunct for radiotherapy.

• Progress in Medical Physics
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• v.18 no.3
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• pp.179-185
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• 2007

The purpose of this study is to investigate the spectra of a magnetic resonance spectroscopy (MRS) in accordance with the variance of TE and the volumes of metabolites in a localized voxel for the quality assurance using a designed single voxel spectroscopy QA phantom. Because a cone-shade phantom is designed as the volume of metabolite in a localized voxel is changeable, we try to analyze the peaks of each metabolite (NAA, Cr, Cho, Lac, etc.) in accordance with metabolite volume in a localized voxel as well as echo time (TE). All data were obtained using a 3T MRI/MRS machine and analyzed using $jMRUI^{(R)}$. The results of this study show that TE is in inverse proportion to the noise of MRS and the longer TE and the less metabolite volume in the localized voxel, the peak intensities of each metabolite decrease. In case of the lactate, its peak was observed on the all TE only if the greatest metabolite is included in the localized voxel. Then, the intensity of a metabolite is more sensitive to the metabolite volume in the localized voxel than the TE. These obtained in vitro MRS data is provide the guideline that is important for in vivo metabolite quantification. But, in the edge of cone-shape vial air bubbles were observed and spectrum could not obtained. Therefore our cone-shape MRS phantom needs to be modified in order to solve these problems.

• Progress in Medical Physics
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• v.19 no.4
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• pp.256-262
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• 2008

To evaluate the metabolic changes in normal adult brains due to alterations SENSE and NEX (number of excitation) by multi voxel MR Spectroscopy at 3.0 Tesla. The study group was composed of normal volunteers (5 men and 8 women) with a mean ($\pm$ standard deviation) age of 41 (${\pm}11.65$). Their ages ranged from 28 to 61 years. MR Spectroscopy was performed with a 3.0T Achieva Release Version 2.0 (Philips Medical System-Netherlands). The 8 channel head coil was employed for MRS acquisition. The 13 volunteers underwent multi voxel spectroscopy (MVS) and single voxel spectroscopy (SVS) on the thalamus area with normally gray matter. Spectral parameters were as follows: 15 mm of thickness; 230 mm of FOV (field of view); 2000 msecs of repetition time (TR); 288 msecs of echo time (TE); $110{\times}110$ mm of VOI (view of interest); $15{\times}15{\times}15$ mm of voxel size. Multi voxel spectral parameters were made using specially in alteration of SENSE factor (1~3) and 1~2 of NEX. All MRS data were processed by the jMRUI 3.0 Version. There was no significant difference in NAA/Cr and Cho/Cr ratio between MVS and SVS likewise the previous results by Ross and coworkers in 1994. In addition, despite the alterations of SENSE factor and NEX in MVS, the metabolite ratios were not changed (F-value : 1.37, D.F : 3, P-value : 0.262). However, line-width of NAA peak in MVS was 3 times bigger than that in SVS. In the present study, we demonstrated that the alterations of SENSE factor and NEX were not critically affective to the result of metabolic ratios in the normal brain tissue.

• Journal of the Korean Magnetics Society
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• v.24 no.3
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• pp.71-75
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• 2014

Ground state energy levels of the $Fe^{3+}$ paramagnetic impurity ion in stoichiometric $LiTaO_3$ and in congruent $LiTaO_3$ single crystals were calculated with electron paramagnetic resonance constants. Energy levels between six energy levels were obtained with spectroscopic splitting parameter g and zero field splitting constant D for $Fe^{3+}$ ion. The energy diagrams of $Fe^{3+}$ ion were different from different magnetic field directions ([100], [001], [111]) when magnetic field increases. The calculated ZFS energies of $Fe^{3+}$ ion in stoichiometric and congruent $LiTaO_3$ single crystals for ${\mid}{\pm}5/2$ > ${\leftrightarrow}{\mid}{\pm}3/2$ > and ${\mid}{\pm}3/2$ > ${\leftrightarrow}{\mid}{\pm}1/2$ > transitions were 12.300 GHz and 6.150 GHz, and 59.358 GHz and 29.679 GHz, respectively. It turns out that energy levels of $Fe^{3+}$ paramagnetic impurity in $LiTaO_3$ crystal are different from different crystal growing condition.

• Journal of the Korean Magnetics Society
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• v.17 no.2
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• pp.60-64
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• 2007

Ba-Ferrite single crystals were prepared and characterized by X-ray, SEM and Mossbauer spectroscopy. The single crystal layers was cut in the c-axis and radiated to the surface by ${\gamma}-rays$ for Mossbauer spectroscopy. We found out that the spin states in Fe atoms were parallel to the ${\gamma}-rays$ direction. The temperature dependence of the hyperfine field is almost similar to that of powder samples. The crystal structure is a Magnetoplumbite without any other phases and the lattice parameters are found out with $a_0=5.892{\AA},\;b_0=5.892{\AA},\;c_0=23.198{\AA}$. $M\"{o}ssbauer$ spectrum in single crystal have 5 sets off absorption lines in each Fe site when the ${\gamma}-rays$ have the same radiation direction with the c-axis in the crystal, which mean that the whole crystal bulk formed only one crystal and same spin direction. The hysteresis curve shows the saturation moment and coercive force of 70.71 emu/g and 320 Oe respectively.

• Journal of the Korean Magnetics Society
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• v.17 no.1
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• pp.47-50
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• 2007

[ $ZnCr_2O_4$ ] shows geometrically frustrated magnet. Recently, $CoCr_2O_4$ has been investigated for multiferroic property and dielectric anomalies by spin-current model. Polycrystalline $CoCr_2O_4$ and $CoCrFeO_4$ compounds was prepared by wet-chemical process. Crystallographic and magnetic properties of $CoCr_2O_4$ and $CoCrFeO_4$ were investigate by using the x-ray diffractometer(XRD), vibrating sample magnetometer(VSM), superconducting quantum interference device magnetometer(SQUID), and $M\"{o}ssbauer$ spectroscopy. The crystal structure was found to be single-phase cubic spinel with space group of Fd3m. The lattice constants of $CoCr_2O_4$ and $CoCrFeO_4$ $a_0$ were determined to be 8.340 and 8.377 ${\AA}$, respectively. The ferrimagnetic transition temperature for the both samples were observed at 97 K and 320 K. The $M\"{o}ssbauer$ absorption spectra at 4.2 K show that the well developed two sextets are superposed with small difference of hyperfine field($H_{hf1}=507\;and\;H_{hf2}=492\;kOe$). Isomer shift values($\delta$) of the two sextets are found to be 0.33 and 0.34 mm/s relative to the Fe metal, respectively, which are consistent with the high spin $Fe^{3+}$ charge state.

• Journal of the Korean Magnetics Society
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• v.18 no.1
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• pp.24-27
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• 2008

We have prepared $MnFe_2O_4$ nanoparticles with polyol method. The crystallographic and magnetic properties were measured by using X-ray diffraction(XRD), vibrating sample magnetometer(VSM) and $M\"{o}ssbauer$ spectroscopy. The high resolution transmission electron microscope(HRTEM) shows uniform nanoparticle-sizes with $6{\sim}8$ nm. The crystal structure is found to be single-phase cubic spinel with space group of Fd3m. The lattice constant of $MnFe_2O_4$ nanparticles is determined to be $8.418{\pm}0.001{\AA}$. $M\"{o}ssbauer$ spectrum of $MnFe_2O_4$ nanparticles at room temperature(RT) shows a superparamagnetic behavior. In VSM analysis, the diagnosis of the superparamagnetic behavior is also shown in hysteresis loop at RT. $M\"{o}ssbauer$ spectrum at 4.2K shows that the well developed two sextets are with different hyperfine field $H_{hfA}=498$(A-site) and $H_{hfB}=521$(B-site) kOe.