• Journal of the Korean GEO-environmental Society
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• v.15 no.12
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• pp.61-69
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• 2014

Carboxymethyl-${\beta}$-cyclodextrin (${\beta}$-CMCD), as a biodegradable surfactant with hydrophobic and hydrophilic properties, has potential advantages of being applicable to the simultaneous treatment of multiple contaminated soils. In this study, the desorption behaviors of r adionuclides such as cobalt (Co), strontium (Sr), and cesium (Cs) from the soil contaminated with them were experimentally investigated and the effectiveness of CMCD as a desorbent was evaluated. The desorption equilibrium of used radionuclides could be achieved within 1~3 hr and the desorption ratio from kaolin was higher than that from natural soil. The addition of CMCD of 2 g/L increased the desorption ratio by 5~20 % and the desorption ratio of used r adionuclides was shown in the order of Co > Cs > Sr. The experimental desorption data were fitted successfully by pseudo-second order kinetic model and the desorption rate of the r adionuclides was shown in the order of Cs > Co > Sr. Hysteresis between adsorption and desorption of the r adionuclides, as shown in the order of Sr > Co > Cs, increased as the desorption rate decreased. Consequently, it could be considered that the desorption rate was one of the significant factors of the hysteresis. The addition of CMCD as desorbent increased the amount of desorbed radionuclides and decreased the hysteresis. However, the CMCD could not completely desorb the radionuclides from soils even though the excess of CMCD was added.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.8 no.1
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• pp.57-63
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• 2010

Layer crystallization process was tested for the separation(or concentration) of cesium and strontium fission products in a LiCl waste salt generated from an electrolytic reduction process of a spent oxide fuel. In a crystallization process, impurities (CsCl and $SrCl_2$) are concentrated in a small fraction of the LiCl salt by the solubility difference between the melt phase and the crystal phase. Based on the phase diagram of LiCl-CsCl-$SrCl_2$ system, the separation possibility by using crystallization was determined and the molten salt temperature profile during layer crystallization operation was predicted by using mathematical calculation. In the layer crystallization process, the crystal growth rate strongly affects the crystal structure and therefore the separation efficiency. In the conditions of about 20-25 l/min cooling air flow rate and less than 0.2g/min/$cm^2$ crystal flux, the separation efficiency of both CsCl and $SrCl_2$ showed about 90% by the layer crystallization process, assuming a LiCl salt reuse rate of 90wt%.

• Journal of the Korean Magnetics Society
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• v.12 no.1
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• pp.14-19
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• 2002

The iron-doped perovskite La$_{0.67}$Sr$_{0.33}$Mn$_{0.99}$$^{57}$Fe$_{0.01}$O$_3$compound has been studied by x-ray diffraction, Mossbauer spectroscopy, and vibrating sample magnetometry. The single phase of the polycrystalline La$_{0.67}$Sr$_{0.33}$Mn$_{0.99}$$^{57}$Fe$_{0.01}$O$_3$powder has been prepared by a waterbased solgel method. Crystalline La$_{0.67}$Sr$_{0.33}$Mn$_{0.99}$$^{57}$Fe$_{0.01}$O$_3$was a rombohedral structure with lattice parameters a$_{0}$=5.480 $AA$, $alpha$=60.259$^{circ}$. Mossbauer spectra of La$_{0.67}$Sr$_{0.3}$/Mn$_{0.99}$$^{57}$Fe$_{0.01}$O$_3$have been taken at various temperatures ranging from 20 to 400 K. As the temperature increases toward the Curie temperature, T$_{c}$=375 K, the Mossbauer spectra show line broadening and the difference between the 1,6 and 3,4 linewidths is caused by the anisotropic hyperfine field fluctuation. The anisotropic field fluctuation of +H (P$_{+}$=0.80) is greater than -H (P$_{-}$=0.20). We calculated that the anisotropy energy was 124.01 erg/cm$^3$for T=150 K which is associated with the large line broadening.

• Phonetics and Speech Sciences
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• v.15 no.4
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• pp.45-51
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• 2023

Voice issues such as voice weakness that arise with age can have social and emotional impacts, potentially leading to feelings of isolation and depression. This study aimed to investigate the changes in acoustic characteristics resulting from aging, focusing on voice quality and spoken fluency. To this end, tasks involving sustained vowel phonation and paragraph reading were recorded for 20 elderly and 20 young participants. Voice-quality-related variables, including F0, jitter, shimmer, and Cepstral Peak Prominence (CPP) values, were analyzed along with speech-fluency-related variables, such as average syllable duration (ASD), articulation rate (AR), and speech rate (SR). The results showed that in voice quality-related measurements, F0 was higher for the elderly and voice quality was diminished, as indicated by increased jitter, shimmer, and lower CPP levels. Speech fluency analysis also demonstrated that the elderly spoke more slowly, as indicated by all ASD, AR, and SR measurements. Correlation analysis between voice quality and speech fluency showed a significant relationship between shimmer and CPP values and between ASD and SR values. This suggests that changes in spoken fluency can be identified early by measuring the variations in voice quality. This study further highlights the reciprocal relationship between voice quality and spoken fluency, emphasizing that deterioration in one can affect the other.

• Journal of the Korean Ceramic Society
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• v.27 no.7
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• pp.841-850
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• 1990

The electrical conductivity of SrTiO3 thick films, which has been prepared by screen printing and sintering on polycrystalline Al2O3 substrates, was determined as a function of oxygen partial pressure and temperature. The data showed that electrical conductivity was proportional to the -1/4th power of the oxygen partial pressure for the oxygen partial pressure range from 10-4-10-8 to 10-20 atm and proportional to Po2+1/4 for the oxygen partial pressure range from 10-6-10-4 to 1atm. And then n-p transition region of electrical conductivity moved to lower oxygen partial pressure region as the sintering temperature of thick film specimens increased under about 140$0^{\circ}C$. These data were consistent with the presence of small amounts of acceptor impurities in SrTiO3 thick film which have been diffused from Al2O3 substrate in the range of solid solubility limit.

• The Journal of Korean Medicine
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• v.21 no.2
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• pp.37-42
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• 2000

Objectives and Methods : Unlike respiratory anaphylaxis responses, mediators responsible for cardiovascular responses are not clearly elucidated. Main characteristics of cardiovascular anaphylaxis include hypotension and cardiac failure (anhythmia and cardiac contraction failure). In this experiment, the fractionations of Sophorae Radix (SR) were tested for its preventive effects against cardiovascular anaphylaxis in pithed rats. Results : Of the SR fractionations, water fractions, at the concentration of 20 and 60mg/kg, was significantly effective on all the cardiovascular changes in pithed rats. Also, of the cardiovascular changes, depressor response was significantly attenuated by the ethyl acetate (EA) fraction, at the concentration of 60mg/kg. Conclusions : These results suggest that water and EA fractions of the SR fractionations possess anti. anaphylactic effects in pithed rats. Additional research is needed to identify active principles for the observed pharmacological effects.

• Journal of the Korean Ceramic Society
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• v.44 no.11
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• pp.627-632
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• 2007

We have studied the ac conductivity of insulating $La_{0.7}Sr_{0.3}FeO_3$ in the frequency range 20 Hz-l MHz and in the temperature range 80-300 K. We have analyzed experimental results in the frame works of the quantum-mechanical tunneling mechanism (QMT) and the hopping of barrier mechanism (HOB). We observed that small polaron QMT model is the most suitable mechanism for the low temperature ac conductivity of $La_{0.7}Sr_{0.3}FeO_3$.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1297-1299
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• 2009

A series of $Eu^{2+}/Mn^{2+}$ co-activated $Ba_{1.98-x}Sr_xZnS_3$ red emission phosphors was synthesized using the polymerizable complex method. The excitation spectra of the materials contain two wide bands centered at 345nm and 445nm, implicating their possible use for white LED lighting applications. In addition, substitution of Sr for Ba by 20% (x=0.4) improved drastically the emission intensity as well as the internal quantum efficiency compared to those for Sr-free $Ba_2ZnS_3:Eu^{2+}/Mn^{2+}$ phosphor.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2018.11a
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• pp.59-61
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• 2018

Highly compressed images typically not only have low resolution, but are also affected by compression artifacts. Performing image super-resolution (SR) directly on highly compressed image would simultaneously magnify the blocking artifacts. In this paper, a SR method based on deep learning is proposed. The method is an end-to-end trainable deep convolutional neural network which performs SR on compressed images so as to reduce compression artifacts and improve image resolution. The proposed network is divided into compression artifacts removal (CAR) part and SR reconstruction part, and the network is trained by three-step training method to optimize training procedure. Experiments on JPEG compressed images with quality factors of 10, 20, and 30 demonstrate the effectiveness of the proposed method on commonly used test images and image sets.

• Journal of Radiation Protection and Research
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• v.22 no.3
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• pp.171-181
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• 1997

A mixed solution of $^{54}Mn$, $^{60}Co$, $^{85}Sr$ and $^{137}Cs$ was applied to the soil of culture boxes in a greenhouse 2 days before transplanting red pepper and at 3 different times during its growth for investigating transfer factors ($m^2/kg-dry$) for its green and red fruits. Transfer factors varied with radionuclide, application time and harvest time by factors of about $20{\sim}100$. They decreased mostly in the order of $^{85}Sr>^{54}Min>^{60}Co>^{137}Cs$ while $^{54}Mn$ and $^{60}Co$ was higher than $^{85}Sr$ when time lapse between application and harvest was short. Transfer factors of $^{85}Sr$ and $^{137}Cs$ at the last application were lower than those at the previous one by factors of $3{\sim}20$ depending on harvest time. Variations in $^{54}Mn$ and $^{60}Co$ transfer factors with application time after transplanting were comparatively low. Transfer factors of $^{54}Mn$, $^{60}Co$ and $^{85}Sr$ mixed with topsoil before transplanting were up to $3{\sim}9$ times higher than those for the application onto soil surface 2 days after transplanting while there was no difference in $^{137}Cs$. The present results can be referred to in estimating root-uptake concentrations of the radionuclides in red pepper fruit and taking proper measures for its harvest and consumption at the event of an accidental release during the growing season of red pepper.