• Journal of Sensor Science and Technology
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• v.19 no.6
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• pp.443-448
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• 2010

In this work, the scintillation properties of CsI:Na crystal were investigated as radiation detection sensor. This scintillation material was grown by a 2-zone vertical Bridgman method. Under X-ray excitation the crystal shows a broad emission band between 280 nm and 690 nm wavelength range, peaking at 413 nm. Energy resolution for $^{137}Cs$ 662 keV $\gamma$-rays of the crystal was measured to be 6.9 %(FWHM). At room temperature, the crystal exhibits three exponential decay time components. The fast and major component of scintillation time profile of the crystal emission decays with a 457 ns time constant. Absolute light yield of the crystal was estimated to be 53,000 ph/MeV using LAAPD. The sample crystal shows proportionality of 30 % in the measured energy range from 31 to 1,333 keV. And the $\alpha/\beta$ ratio of the crystal was 0.14.

• Journal of Microbiology and Biotechnology
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• v.24 no.3
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• pp.334-336
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• 2014

A new species named Aspergillus cumulatus sp. nov. is described in Aspergillus section Aspergillus (Eurotium state). The type strain (KACC $47316^T$) of this species was isolated from rice straw used in meju fermentations in Korea, and other strains were isolated from the air in a meju fermentation room. The species is characterized by growth at a wide range of water activities and the formation of aerial hyphae on malt extract 60% sucrose agar (ME60S) that resemble a cumulus cloud. Furthermore, A. cumulatus produces yellow ascomata containing small lenticular ascospores (5.1-5.7 ${\mu}m$) with a wide furrow, low equatorial crests, and tuberculate convex surface. The species is phylogenetically distinct from the other reported Aspergillus section Aspergillus species based on multilocus sequence typing using rDNA-ITS, ${\beta}$-tubulin, calmodulin, and RNA polymerase II genes.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.1162-1164
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• 1993

The Thermally Stimulated Current(TSC) spectroscopy has been applied to study the influence of the structual cahange and interface on the electrical properties of epoxy composites. Three DGEBA-MeTHPA matrix model samples mixed different ratios and silica($SiO_2$) filled sample and silaln treating-filled sample has been studied. Above room temperature, the relaxation mode $\alpha$ peak associated with Tg has been located at $110^{\circ}C$. Below glass transition temperature(Tg), three relaxation modes are observed in all samples: a $\beta$ mode situated at $10^{\circ}C$, a $\gamma$ mode located at $-40^{\circ}C$ and a $\delta$ mode appeared in $-120^{\circ}C$. The analysis of its fine structure indicates that constitution of elementary processes is characterized by the activation energy and relaxation time. Also the dielectric relaxation properties have been investigated to compare the the change of the molecular structure and motion to the relaxation properties and conduction mechanism in TSC spectra.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.195-195
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• 2010

$Ga_2O_3$ thin films have been grown on Si(001) substrates by metalorganic chemical vapor deposition (MOCVD) using dimethylgallium isopropoxide ($Me_2GaO^iPr$, DMGIP) with oxygen as the reactant gas. Suitability of the precursor for CVD was confirmed by thermogravimetric analysis (TGA) and vapor pressure measurement. Deposition was carried out in the substrate temperature range $450-650^{\circ}C$. Spectroscopic ellipsometry, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) and Rutherford back-scattering spectroscopy (RBS) were used to determine the thickness, crystallinity, and composition and stoichiometry of the films, respectively. From the slope of the Arrhenius plot in the temperature range $500-550^{\circ}C$, the activation energy of deposition was found to be $225.5\;kJ\;mol^{-1}$. As-deposited films were amorphous, but the monoclinic $\beta-Ga_2O_3$ phase was revealed after annealing the films in air at $1050^{\circ}C$. The XPS and RBS analyses indicate that the $Ga_2O_3$ films obtained by using DMGIP were found to be almost stoichiometric.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.05a
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• pp.236-237
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• 2012

ZnO nanorods were grown on R-plane sapphire substrates with the seed layers annealed at different temperature. The effects of annealing temperature for the seed layers on the properties of the ZnO nanorods were investigated by scanning electron microscopy, X-ray diffraction, UV-visible spectroscopy, and photoluminescence. For the as-prepared seed layers, the ZnO nanorods and the ZnO nanosheets were observed. Only the ZnO nanorods were grown as the annealing temperature was above $700^{\circ}C$. The optical transmittance in the UV region was almost zero while that in the visible region was gradually increased as the annealing temperature increased to $700^{\circ}C$. The optical band gap of the ZnO nanorods was increased as the annealing temperature increased to $700^{\circ}C$. In the visible region, the refractive index was decreased with increasing the wavelength, and the extinction coefficient was decreased as the annealing temperature increased to $700^{\circ}C$. The non-linear exciton radiative life time of the FX emission peak was established by cubic equation. The values of Varshni's empirical equation fitting parameters were ${\alpha}=4{\times}10^{-3}eV/K$, ${\beta}=1{\times}10^4K$, and $E_g(0)=3.335eV$ and the activation energy was found to be about 94.6 meV.

• Archives of Pharmacal Research
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• v.8 no.3
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• pp.119-132
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• 1985

The apparent effectiveness of 1-naphthyl-N-methyl carbamate (carbaryl) against a wide variety of insects motivated the study of its mammalian toxicity. In this toxicological study of carbaryl, mature male rats inhaled carbaryl at a mean concentration of 112mg, 168mg and 224 mg/$m^{3}$ for one hour. After inhalation, pentobarbital sleeping time, Nadph-cytochrome c reductase activity, cytochrome p-450 and protein content in liver microsomes, various tissue residues, cholinesterase inhibition in plasma and histopathological findings at autopsy were observed. The pentobarbital sleeping time was prolonged in rats inhaled with carbaryl for one day while the sleeping time was shortened in the 3 days inhaled group. The changes of cytochrome p-450 content and NADPH-cytochrome c reductase activity exhibited biphasic response showing the decrease in the one day inhaled group and the increase in the 3 days inhaled group. The marked depression of plasma ChE activity was observed in rats inhaled with carbaryl at 112 mg/$m^{3}$, however no more progressive effect was observed at the higher concentration of the compound. The main observations in histopathological finding were ciliary detachment, epithelial swelling and subepithelial inflammatory cellular infiltration in trachea due to the irritation.

• Nuclear Engineering and Technology
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• v.51 no.7
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• pp.1860-1865
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• 2019

The confinement degradation of the energetic particles during RMP would be a key issue in success of realizing the successful energy production using fusion plasma, because a 3.5 MeV energetic alpha particle should be able to sustain the burning plasma after the ignition. As KSTAR recent results indicate the generation of high-performance plasma(${\beta}_p{\sim}3$), the confinement of the energetic particles is also an important key aspect in neutral beam driven plasma. In general, the measured absolute value of the neutron intensity is generally used for to estimating the confinement time of energetic particles by comparing it with the theoretical value based on transport calculations. However, the availability of, but for its calculation process, many accurate diagnostic data of plasma parameters such as thermal and incident fast ion density, are essential to the calculation process. In this paper, the time evolution of the neutron signal from an He3 counter during the beam blank has permitted to facilitate the estimation of the slowing down time of energetic particles and the method is applied to investigate the fast ion effect on ELM suppressed KSTAR plasma which is heated by high energy deuterium neutral beams.

• Nuclear Engineering and Technology
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• v.54 no.3
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• pp.991-996
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• 2022

Microstructures of monolithic high purity SiC and SiC with sintering additives after neutron irradiation to a fluence of 2.0-2.5 × 10²⁴ n/m² (E > 0.1 MeV) at 333-363 K and after post-irradiation annealing up to 1673 K were observed using a transmission electron microscopy. Results showed that no black spot defects or dislocation loops in SiC grains were found after the neutron irradiation for all of the specimens owing to the moderate fluence at low irradiation temperature. Thus, it is confirmed that these specimens were swelled mostly by the formation of point defects. Black spots and small dislocation loops were discovered only after the annealing process in PureBeta-SiC and CVD-SiC, where the swelling almost diminished. Anomalous-shaped YAG grains were found in SiC ceramics containing sintering additives. These grains contained dense black spots defects and might lose crystallinity after the neutron irradiation, while these defects may annihilate by recrystallization during annealing up to 1673 K. Amorphous grain boundary phase was also presented in this ceramic, and a large part of it was crystallized through post-irradiation annealing and could affect their recovery behavior.

• The Korean Journal of Mycology
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• v.39 no.1
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• pp.68-77
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• 2011

80% methanol and 0.9% neutral saline soluble and hot water substances (hereinafter referred to Fr. NaCl, Fr. HW and Fr. MeOH, respectively) were extracted from fruiting bodies of Grifola frondosa. In vitro cytotoxicity tests, crude polysaccharides were not cytotoxic against cancer cell lines such as Sarcoma 180 and RAW 264.7 at the concentration of 10~2000 ${\mu}g/ml$, but crude polysaccharides from Fr. NaCl was slightly toxic to HT-29 and NIH3T3 at the concentration of 2000 ${\mu}g/ml$. Intraperitoneal injection with crude polysaccharides exhibited life prolongation effect of 25.0~52.9% in mice previously inoculated with Sarcoma 180. Fr. HW increased the numbers of spleen cells by 1.3 fold at the concentration of 200 ${\mu}g/ml$ compared with control. Fr. NaCl improved the immuno-stimulating activity of B lymphocyte by increasing the alkaline phosphatase activity by 1.5 fold compared with control at the concentration of 200 ${\mu}g/ml$. 10~14 ${\mu}M$ of nitric acid were generated when Fr. NaCl was added to RAW 264.7 at the concentration of 50~500 ${\mu}g/ml$, while the control group produced 4.3 ${\mu}M$ of nitric oxide. The Fr. NaCl, Fr. HW and Fr. MeOH increased the production of TNF-${\alpha}$, IL-$1{\beta}$, Il-2 and IL-6 by more than 1.4 times compared with the control group. The Fr. of MeOH increased the numbers of peritoneal exudate cells and circulating leukocytes by 3.0 and 2.0 folds compared with the control at the concentration of 50 ${\mu}g/ml$, respectively. Therefore, the crude polysaccharides extracted from fruiting bodies of Grifola frondosa could improve antitumor activity of mice.

• The Journal of Korean Obstetrics and Gynecology
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• v.19 no.4
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• pp.61-76
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• 2006

Purpose : This study examined the non-toxic and the anti-oxidative effect of Dioscoreae Rhizoma on PC12 cells. Sanyak(Dioscoreae Rhizoma; chinese yam, shan yao) is well-known for its curing power for kidney, lung, spleen. Tonifies and augments the spleen and stomach. Tonifies the lung gi and augments the kidney yin. Tonifies the kidneys and also stabilizes and binds. it also binds the essence and treats spermatorrhea, frequent urination, and vaginal discharge. We are therefore interested in whether Dioscoreae Rhizoma is capable of causing abnormal apoptosis processes, and whether this condition can be rectified through Dioscoreae Rhizoma herb treatment. Methods : We used aqueous extract to treat PC12 cells with different concentrations treated with a water or a MeOH extract of Dioscoreae Rhizoma (0, x10, x20, x40, x80). The MTT (3, (4, 5-dimethyl-thiazol) 2, 5-diphenyl-tetraxolium bromide) reduction assay was employed to quantify the differences in cell activity and viability. The Bax expression level was monitored using western-blotting techniques. The patterns of the changes in expression were scanned and analyzed. Results : Bax and GSK-3${\beta}$ promotes cell death and down-regulated during the development of the PC12 cells. This is indicated that Dioscoreae Rhizoma is capable of inducing apoptosis in PC12 cells. The induced cell death and significantly inhibited by Dioscoreae Rhizoma, which can be explained by the increase in the inhibition of Bax and GSK-3${\beta}$ expression. It was also shown that Dioscoreae Rhizoma inhibits the release of $H_2O_2$ and prevents lipid peroxidation. Furthermore, the accumulation of wild type Bax protein significantly downregulated in a dose-dependent manner upon treatment with Dioscoreae Rhizoma. Conclusion : In conclusion, Dioscoreae Rhizoma can induce apoptosis via a Bax-dependent pathway or GSK-3${\beta}$ dependent pathway in PC12 cells into anti-oxidant and protective effect.