• Journal of the Korean Magnetics Society
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• v.8 no.4
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• pp.203-209
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• 1998

Crystallographic and magnetic properties of single phase garnet $Y_{3-x}Bi_xFe_5O_{12}$ (x=0.0, 0.25, 0.5, 0.75, 1.0) were studied by using x-ray diffraction, Mossbauer spectroscopy and vibrating sample magnetometer (VSM). Ultra-fine polycrystalline cubic samples have been prepared by sol-gel method. The lattice constant increase linearly with increasing an amount of Bi. Annealing temperature was larger than 800 $^{\circ}C$ for the growth of a single-phase garnet powder. The second phase of garnet, $(BiFeO_3)$, was at 1000 $^{\circ}C$ for x=0.75, and 950 $^{\circ}C$ for x=1.00. From Mossbauer spectroscopy and VSM measurements, the magnetization and the coercivity were decreased and the Curie temperature $Y_{3-x}Bi_xFe_5O_{12}$(x=0.0, 0.25, 0.5, 0.75, 1.0) was slightly increased as increasing the Bi content.

• Proceedings of the Materials Research Society of Korea Conference
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• 2007.11a
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• pp.95.1-95.1
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• 2007

• Journal of the Korean Magnetics Society
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• v.3 no.3
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• pp.196-200
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• 1993

$(Sm_{0.5}RE_{0.5})Fe_{11}Ti$ compounds have tetragonal $ThMn_{12}$-type structure and show the uniaxial magnetocrystalline anisotropy with the easy magnetization c-axis. Among the $(Sm_{0.5}RE_{0.5})Fe_{11}Ti$ series, RE=Sm shows the highest anisotropy field of 11200 kA/m(140 kOe). On the other hand, RE=Nd has the highest saturation magnetization of $122.3\;Am^{2}/kg$(122.3 emu/g) and RE=Gd the highest Curie temperature of $326^{\circ}C$.

• Applied Biological Chemistry
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• v.40 no.2
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• pp.123-127
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• 1997

To improve the quality and prolongation of chopped ginger, they were treated with NaCl, citric acid, ascorbic acid alone or combination of them at $5^{\circ}C$. The browning and stink of chopped ginger were prevented by adding 10% NaCl, $0.5{\sim}2.0%$ citric acid, but the control became severely browned and deteriorated after 1 month storage. The application of 0.5% citric acid maintained citrine color and decreased the activity of polyphenol oxidase(PPO) more significantly compared to 5.0% NaCl or 0.5% ascorbic acid. Ascorbic acid treatment become browned at $1.0{\sim}2.0%$ and easily deteriorated compared to citric acid. Citric acid(0.5%) or ascorbic acid (0.5%) treatment was largely variation of pH compared to NaCl(5.0%)+citric acid(0.5%) or NaCl(5.0%)+ascorbic acid(0.5%) treatment during 8 month storage. The activity of PPO in NaCl(5.0%)+ascorbic acid(0.5%) treatment was elevated after 4 month storage. In chopped ginger, NaCl(5.0%)+citric acid(0.5%)+ascorbic acid(0.25%) treatment was more effective than 5.0%+0.1%+0.1%, 5.0%+0.5%+0.1% during 12 month storage.

• Journal of the Chungcheong Mathematical Society
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• v.26 no.4
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• pp.923-926
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• 2013

We find congruence properties on the coefficients of modular forms for ${\Gamma}^+_0(5)$ generated by ${\Gamma}_0(5)$ and a Fricke involution $\(_{5\;0}^{0\;-1}\)$.

• Journal of the Korean Magnetics Society
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• v.17 no.1
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• pp.14-17
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• 2007

Magnetic properties of transition metal doped $La_{0.5}Ca_{0.5}(Mn_{0.98}TM_{0.02})O_3$(TM=Cr and Ti) are studied. The samples are synthesized by the conventional solid-state method. Using vibrating sample magnetometer magnetization-temperature measurement were carried out with zero field cooling and field cooling at 50 Oe. Cr-doped sample shows cluster or spin glass like behavior while Ti doped does not. Curie temperature obtained were decreased from that of LCMO(245.5 K). Curie temperatures of Cr-doped and Ti-doped samples are 235.5 K and 232.7 K, respectively. The temperature-dependent coercivity $H_c(T)$ was also measured. The coercive force continuously decreases with the substitution of Cr and Ti, The result can be understood in terms of the interaction between defect and domain wall.

• Journal of the Korean Society of Radiology
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• v.17 no.1
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• pp.17-23
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• 2023

In this study, the thermoluminescence kinetics of electron trap in Li₆Y_0.5Gd_0.5(BO₃)₃ (LY_0.5G_0.5BO) scintillator for neutron detection composed of Li, Gd, and B with a high neutron response cross-section were investigated. The thermoluminescence glow curve of the LY_0.5G_0.5BO scintillation single crystal was measured and analyzed using the peak shape method, the initial rise method, and the machine learning algorithm to evaluate the physical parameters of the electron trap. The glow curve of the LY_0.5G_0.5BO scintillation single crystal consisted of a single peak. As a result of analyzing this peak, the activation energy, emission order, and frequency factor of the electron trap were 0.61 eV, 1.1, and 1.7×10⁷ s^-1, respectively. In addition, the possibility of thermoluminescence analysis of scintillators using machine learning was confirmed.

• Journal of the Korean Society of Propulsion Engineers
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• v.5 no.3
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• pp.60-70
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• 2001

The study of compatible liner with ADP-505 propellant based PCP was performed. HTPB/DDl was chosen as a binder of liner in order to prohibit migration of nitroester plasticizer from propellant. The possible formulations for liner were screened by peel test of EPDM insulation/liner, propellant/liner and insulation/liner/propellant. Also, the adhesion tests including tension and shear were conducted. The adhesion of liner and propellant fumed out to be very good. The peel value was shown 1.5∼1.8 daN/cm, tensile force was 5.5∼6.0bar and shear force was 4.2∼5.0bar. In the samples of insulation/liner/propellant, they also have shown good adhesion properties. The peel, tensile and shear strength were 1.8 daN/cm, 5.0∼6.0bar and 4.5∼5.0bar, respectively.

• Journal of the Microelectronics and Packaging Society
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• v.11 no.4 s.33
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• pp.43-48
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• 2004

Electromigration of Sn-3.5Ag-0.5Cu solder bumps was investigated with current densities of $3{\~}4{\times}10^4 A/cm^2$ at temperatures of $130{\~}160^{\circ}C$ using flip chip specimens which consisted of upper Si chip and lower Si substrate. Electromigration failure of the Sn-3.5Ag-0.5Cu solder bump occurred with complete consumption of Cu UBM and void formation at cathode side of the solder bump. The activation energies for electromigration of the Sn-3.5Ag-0.5Cu solder bump were measured as 0.61 eV at current density of $3{\times}10^4 A/cm^2$, 0.63 eV at $3.5{\times}10^4 A/cm^2$, and 0.77 eV at $4{\times}10^4 A/cm^2$, respectively.

• Journal of the Korean Ceramic Society
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• v.41 no.1
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• pp.9-12
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• 2004

The effect of x wt% CuO-y wt% $V_2O_5$ content on the microwave properties of $(Pb_{0.45}Ca_{0.55})[(Fe_{0.5}Nb_{0.5})_{0.9}Sn_{0.1}]O_3$ (PCFNS) ceramics was investigated. In order to decrease the sintering temperature and use as a Low Temperature co-firing Ceramics (LTCC), CuO-$V_2O_5$ are added in the PCFNS. The bulk density, dielectric constant (${\varepsilon}_r$) and quality factor(Q${\cdot}f_0$) increased with increase in CuO content within a limited value. The microwave properties were degraded with increases in $V_2O_5$ content. The temperature coefficient of the resonant frequency (${\tau}_f$) of PCFNS was shifted to positive value abruptly with increasing the $V_2O_5$ content, while the ${\tau}_f$ was slightly shifted to positive value with increasing the CuO content. The optimized microwave properties, ${\varepsilon}_r$ = 88, Q${\cdot}f_0$ = 6100 (GHz), and ${\tau}_f$ = 18 ppm/$^{\circ}C$, were obtained in $(Pb_{0.45}Ca_{0.55})[(Fe_{0.5}Nb_{0.5})_{0.9}Sn_{0.1}]O_3$ with 0.2wt% CuO 0.05 wt% $V_2O_5$ and sintered at $1000^{\circ}C$ for 3 h. The relationship between the microstructure and microwave dielectric properties of ceramics was studied by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM)