• Journal of the Korean Physical Society
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• v.73 no.12
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• pp.1884-1888
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• 2018

We have employed electron paramagnetic resonance spectroscopy and magnetization measurements in order to study the effect of Al-incorporation on the magnetic interactions in ZnO:Mn diluted magnetic semiconductors. Al-doping is shown to decrease the antiferromagnetic correlation and to increase the ferromagnetic interaction, which is attributed to the hydrogen-mediated ferromagnetic Mn complexes in our Mn-doped ZnO samples.

• Nuclear Engineering and Technology
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• v.50 no.3
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• pp.526-530
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• 2018

Human fingernails were used to estimate the radiation dose via electron paramagnetic resonance measurements of radiation-induced radicals. The limiting factors in this research were mechanically induced electron paramagnetic resonance signals due to the mechanical stress during the preparation of the samples. Therefore, different treatment methods of fingernails were used to reduce the mechanically induced signals. The results demonstrate that the mechanically induced and radiation-induced signals have apparently different microwave power saturation behaviors. In addition, the mechanically induced signal shows a fading evolution over time and reaches a constant value. Chemical treatment using the different reagents showed that the minimum mechanically induced signal was obtained using the dithiothreitol reagent. The dose-response curves of the samples treated with dithiothreitol for 30 minutes demonstrated a greater linearity than those of samples treated for 5 minutes. Therefore, to find an unknown absorbed dose in a fingernail sample using a calibration curve, we recommend adopting the mentioned chemical treatment procedure to reduce the uncertainty.

• Journal of Magnetics
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• v.2 no.4
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• pp.123-125
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• 1997

We have studied a series of I2-doped poly [2-buthoxy-5-methoxy-1, 4-phenylenevinylene] (PBMPV) conducting polymers by means of electron paramagnetic resonance (EPR) measurements. In this work, the EPR linewidth and spin density were obtained from the EPR intensity and studied as a function of the degree of doping.

• Journal of Magnetics
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• v.17 no.4
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• pp.271-274
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• 2012

We examine dosimetry application of irradiated D-fructose materials using electron paramagnetic resonance (EPR). Consequently, we consider that fructose is one of best dosimetry materials. We found that fructose is one of best candidates for dosimetry due to high linearity tilt of EPR signal intensity as a function of dose, irrelevant to photon energy, constant fading value. Also, our results show that fructose materials can be applied as a radiation detector to very weak radiation doses of 0.001 Gray by using EPR at a low temperature (T = 220 K).

• Journal of Magnetics
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• v.17 no.4
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• pp.255-260
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• 2012

In this study, we determine that the electron paramagnetic resonance line-width (EPRLW) is axially symmetric about the c-axis and analyze the spin Hamiltonian with an isotopic g-factor of 1.9920 at a frequency of 9.5 GHz. It should be noted that the electron paramagnetic resonance signals are Lorentzian. Our findings show that the EPRLW decreases exponentially with an increase in the temperature; i.e., its temperature dependence in the range 300-400 K obeys Arrhenius behavior, this kind of temperature dependence indicates an off-center a motional narrowing of the spectrum when $Mn^{2+}$ impurity ions substitute for $Nb^{5+}$ ions. The specific heats follow a linear dependence suggesting a simple Debye $T^3$ behavior.

• Journal of Magnetics
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• v.17 no.3
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• pp.172-175
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• 2012

We present a method for detecting very weak radiation by analyzing the inner structure of irradiated tris (lyoluminescence) materials using electron paramagnetic resonance (EPR) at low temperature. Organic materials have been looked into for use in emergency dosimetry of inhabitants around radiation accidents. However, this technology has never been applied to imperceptible radiation doses (< 0.5 Gy) because there is no proper method for detecting the change of inner structure of the subject bombed by very weak radiation at room temperature. Our results show that tris materials can be applied as a radiation detectors of very small radiation doses below 0.05 Gray, if EPR is used at low temperature (130 K ${\leq}$ T ${\leq}$ 270 K). The EPR signal intensity from the irradiated-tris sample had barely faded at all after 1 year.

• 전기의세계
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• v.21 no.3
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• pp.53-56
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• 1972

Electron paramagnetic resonance is one of the concrete forms of magnetic resonance and the superposition of an external magnetic field causes an orientation of the magnetic moment of an atom. On the assumption that both pumped levels be saturated and all relaxation times equal the inversion ratio for a push-pull paramagnetic maser is obtained and compared with those of three-level paramagnetic masers and the magnetic field intensities for 9 and 10 Gc push-pull ruby maser oriented with an angle of 54.deg.44' between the caxis and the magnetic field are, also, obtained.

• Bulletin of the Korean Chemical Society
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• v.11 no.2
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• pp.85-88
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• 1990

The electron paramagnetic resonance (EPR) spectrum of the copper (II) complex with the 2-methylamino-1-cyclo-pentene-1-dithiocarboxylate (acdc) anion, $Cu(N-CH_3acdc)_2$ has been studied in the diamagnetic host lattices afforded by the corresponding divalent nickel, zinc, cadmium and mercury complexes. EPR parameters of the complex support the exclusive use of sulfur atoms by the ligand in metal binding. A combination of host lattice structure and covalency effects can be account for the observed spin-Hamiltonian parameters.

• Proceedings of the Korean Magnetic Resonance Society Conference
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• 2002.01a
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• pp.30-30
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• 2002

• Proceedings of the Korean Magnetic Resonance Society Conference
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• 2002.01a
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• pp.18-18
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• 2002