• Journal of Microbiology and Biotechnology
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• v.9 no.6
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• pp.709-715
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• 1999

A series of antifungal compounds were obtained from the methanol extract of the mycelium from marine actinomycetes M428 which was identified as a Stereptomyces species by fatty acid composition and biochemical characteristics. These compounds were purified by combined chromatographic techniques and the structures were characterized with spectroscopic methods including 1D and 2D NMR, and mass spectrometry as sn-l lysophosphatidyl inositols. The side chains were established by chemical degradation followed by GC analysis to be 14-methyl pentadecanoic acid (iso-palmitic acid, i-C16:0, compound A) and 13-methyl tetradecanoic acid (iso-pentadecanoic acid, i-C15:0, compound B). These compounds displayed highly selective antifungal activity against C. albicans with MIC values of $5{\;}\mu\textrm{g}/ml$ (compound A) and $2.5{\;}\mu\textrm{g}/ml$ (compound B), while it had almost negligible antibiotic activity against E. coli and P aerogenosa with MIC value higher than $50{\;}\mu\textrm{g}/ml$ and no cytotoxic activities against human myeloma leukemia K562 ($IC_{50}>100{\;}\mu\textrm{g}/ml$).

• Journal of the Korean Ceramic Society
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• v.39 no.7
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• pp.635-641
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• 2002

Electrical conduction of $SrZrO_3$ doped with $Y_2O_3$ was measured as a function of gas atmosphere and temperature by impedance spectroscopy. Hydrogen dissolution, due to an enhanced driving force in the presence of oxygen, results in protonation by water incorporation. Proton conductivity increased with water vapor pressure, ${P_w}^{1/2}$. In the pure hydrogen atmosphere, the dissolution of hydrogen,$H_2(g)=2H_{i}$ +2e', is supposed to be driven by a reduced activity of electrons, ascribable to their trapping in oxygen vacancies. The activation energy of electrical conductivity was 50 kJ/mol, in wet argon atmosphere in the temperature range of $600~900^{\circ}C$, similar to those reported for proton conduction in the literature. Grain boundary effect in proton conduction was substantial in the 10% doped case at temperatures lower than $700^{\circ}C$.

• Journal of the Korean Geotechnical Society
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• v.24 no.11
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• pp.157-166
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• 2008

To investigate the relationship between compressive strength ($q_u$) of Lightweight Air-mixed soil (LAS) and its physical deformation coefficient ($E_{50}$), a series of unconfined compressive tests have been performed on specimens of LAS according to various dredged soil types by percentage of sand, silt and clay. From the results it was found that the cement content ($C_i$) and unit weight (${\gamma}_m$) are most influence factors on strength, and percentage of sand, silt, clay by grain size analysis (KS F2302) have more effect on compressive strength than other physical properties of soil. It was also found that the rate of strength (a) increases with curing time, but it reduces with the increase of percentage of clay ($C_%$).

• Geophysics and Geophysical Exploration
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• v.25 no.3
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• pp.140-161
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• 2022

Seismic data with missing traces are often obtained regularly or irregularly due to environmental and economic constraints in their acquisition. Accordingly, seismic data interpolation is an essential step in seismic data processing. Recently, research activity on machine learning-based seismic data interpolation has been flourishing. In particular, convolutional neural network (CNN) and generative adversarial network (GAN), which are widely used algorithms for super-resolution problem solving in the image processing field, are also used for seismic data interpolation. In this study, CNN-based algorithm, U-Net and GAN-based algorithm, and conditional Wasserstein GAN (cWGAN) were used as seismic data interpolation methods. The results and performances of the methods were evaluated thoroughly to find an optimal interpolation method, which reconstructs with high accuracy missing seismic data. The work process for model training and performance evaluation was divided into two cases (i.e., Cases I and II). In Case I, we trained the model using only the regularly sampled data with 50% missing traces. We evaluated the model performance by applying the trained model to a total of six different test datasets, which consisted of a combination of regular, irregular, and sampling ratios. In Case II, six different models were generated using the training datasets sampled in the same way as the six test datasets. The models were applied to the same test datasets used in Case I to compare the results. We found that cWGAN showed better prediction performance than U-Net with higher PSNR and SSIM. However, cWGAN generated additional noise to the prediction results; thus, an ensemble technique was performed to remove the noise and improve the accuracy. The cWGAN ensemble model removed successfully the noise and showed improved PSNR and SSIM compared with existing individual models.

• Journal of the Korean Magnetics Society
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• v.14 no.1
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• pp.18-24
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• 2004

Ni-Zn ferrite powder was synthesized from metal nitrates, Fe(N $O_3$)$_3$$.$9 $H_2$O, Ni(N $O_3$)$_2$$.$6 $H_2$O, Zn(N $O_3$)$_2$$.$6 $H_2$O by wet direct process to make high permeability material. The composition of the ferrite powder is (N $i_{0.284}$F $e_{0.053}$Z $n_{0.663}$)F $e_2$ $O_4$. Ni-Zn ferrite powder is compounded by precipitating metal nitrates with NaOH in vessel at 90$^{\circ}C$ synthetic temperature for 8 hours. Calcination temperature and sintering temperature were 700$^{\circ}C$ and 1150$^{\circ}C$-1250$^{\circ}C$ respectively for 2 hours. The same compound powder was extracted from metal oxide by wet ballmilling. We compared the properties of powder and the electromagnetic characteristics of the sintered cores obtained from the two different processes. Wet direct process produces smaller particle size with narrower distribution and higher purified ferrite which cores has high permeability and high magnetization.

• Progress in Superconductivity
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• v.7 no.2
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• pp.174-178
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• 2006

For the practical application on SCFCL, Bi2212 tubes were fabricated by Centrifugal Forming Process (CFP) in terms of many different processing parameters. Typical sizes of tubes were 60, 150 mm in length and 2.5, 3.5, 4.8 mm in thickness. Initially powder was melted by induction heating. The optimum range of melting temperatures and preheating temperature were $1100^{\circ}C$ and $500^{\circ}C$ for 30min respectively. The nominal mold rotating speed was around 1000 RPM. A tube was annealed at $840^{\circ}C$ for 80 hours in oxygen atmosphere. The tube of 50mm x 70mm x 2.5mm, rotated with 1000 RPM showed $I_c=890\;A\;and\;T_c=80$. It was found that the tube processed with faster rate of mold rotation speed, thinner tube thickness and shorter tube length shows better electric characteristics as compared with the tube normally processed. In order to study the uniformity heat and fluid flow analysis tool was adopted along tube.

• The Plant Pathology Journal
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• v.18 no.2
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• pp.81-84
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• 2002

Effects of temperature and dew period on sporulation of a mycoherbicide, Epicoccosorus nematosporus, on the lesion of its host, Eleocharis kuroguwai were determined. Conidia formation was first observed after 10 days on plants incubated for either 12 or 16 h in a dew chamber at 28$^{\circ}C$; 16 h dew period resulted in more conidia formation. As the dew period was decreased to less than 8 h, fewer conidia formed. Conidial production was most abundant at 28$^{\circ}C$ and produced as much as 3.3$\times$10$^4$conidia per lesion, while 0.1$\times$10$^3$and 2.3$\times$10$^3$conidia per lesion were produced at 16$^{\circ}C$ and 36$^{\circ}C$, respectively. Alternating temperature regimes, i.e., 30/15, 30/20, 28/20, and 28/15$^{\circ}C$ (day/night) were much better than constant temperature, i.e., 30/30, 28/28/, and 20/2$0^{\circ}C$ for sporulation. In the second sporulation, there were as much as 3.1$\times$10$^4$conidia per lesion (ca. <50% of the first sporulation). Then, sporulation dropped sharply to 6.2$\times$10$^2$conidia per lesion in the third sporulation. Results of this study suggest that temperature combined with dew period is the primary limiting factor in the use of E. nematosporus as a mycoherbicide off, kuroguwai.

• Korean Journal of Animal Reproduction
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• v.10 no.1
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• pp.27-35
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• 1986

As a preliminary experiment to establish the process on the sexing of mouse embryos by chromosomal analysis, present studies were carried out with inbred (ICR, C57BL) and F1 hybrid [(ICR${\times}$C57BL) = F1 ${\times}$ ICR] mice to investigate the blastomere numbers and mitotic indices (M.I.) to the developmental stage of embryos recovered, the optimum periods of anti-mitotic agent administration, the successful rates of sexing and sex-ratio. The results obtained were summarized as follows: 1. The blastomere numbers (mean${\pm}$S.E.) of the morula and blastocyst were 18${\pm}$0.4 and 54${\pm}$0.7, respectively. 2. Whereas the M.I. of F1 hybrid (16${\pm}$0.2%) was higher than that fo inbred ICR (15${\pm}$0.1%) and C57BL (12${\pm}$0.6%) in the different strains, the morula (7${\pm}$0.6%) was higher than that of blastocyst (6${\pm}$0.4%) in the case of embryo stages. 3. Following to anti-mitotic agents treated, the M.I. of embryos cultured with Colcemid (17${\pm}$1.1%) was superior to that fo embryos cultured with Velban (12${\pm}$0.9%) and the Colcemid injection (7${\pm}$0.4%). 4. The successful rate of sexing in the blastocyst (38.7%; 124/320) was superior to the morula (35.9%; 52/145), and the F1 hybrid (48.1%) was higher than that of inbred ICR (42.4%) and C57 BL (28.2%). 5. In the successful rate of sexing to the methods of administration, the embryos cultured with Colcemid (46.0%) was superior to that of embryos cultured with Velban (39.0%) and the Colcemid injection (38.8%). 6. Of 98 embryos sexed after culture with Colcemid, 89(90.8%) were observed between 2 and 4 hrs. In the case of Velban treatment, 83.1% (74/89) was observed between 2$\frac{1}{2}$ and 4$\frac{1}{2}$ hrs. 7. Out of 761 prepared embryos it was possible to sex 311; 157 were male and 154 were female, i.e.a sex-ratio of 50% a, pp.oximately.

• Journal of Microbiology and Biotechnology
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• v.1 no.3
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• pp.157-162
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• 1991

Conditions for glutathione production in E. coli cells which possess pGH501 (2 gshI+gshII) were studied. In terms of ATP supply for the glutathione synthesis, two different systems have been constructed and compared. When the acetate kinase reaction of E. coli was used for ATP generation, 20 mM of L-cysteine was completely converted to glutathione by toluene-treated E. coli cells (100 mg/ml) harboring pGH501 within 2 h at $37^{\circ}C$. However, considering the economical aspects, the glycolytic pathway of yeast was chosen as a better system for ATP generation. The optimal concentrations of reactants for glutathione production were determined to be as follows; 80 mM L-glutamate, 20 mM L-cysteine, 20 mM glycine, 20 mM $MgCl_2$, 50 mM potassium phosphate buffer (pH 7.5), 400 mM glucose, polyoxyethylene stearylamine ($5\;\mul/ml$), toluene-treated E. coli HB101/pGH501 (100 mg/ml), and dried yeast cells (400 mg/ml). The conversion ratio of L-cysteine to glutathione was 80% (about 5 mg/ml) under optimal condition within 6 h at $37^{\circ}C$.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.6
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• pp.73-81
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• 2018

In this study, subsurface discharge performance has been studied through theoretical seepage analysis on four types of culverts that can be installed under the condition of non-excavation, such as (a)perforated pipe(${\Phi}50mm$), (b)perforated pipe+horizontal mat (B50cm) (c)perforated pipe+horizontal mat+vertical gravel(B<10cm), (d)perforated pipe+vertical gravel(B<10cm), and existing typical type (e)perforated pipe with gravel (B40, h=40cm) which can be installed by excavation. The analysis results were as follows. i) Subsurface discharge performance per unit (m) was (a)type 56%, (b) 91%, (c) 96%, (d) 76%, respectively, lower than the value of (e)culvert. ii) However, considering that non-excavation culvert can be installed at a spacing of 5m with the installation cost of the existing excavation culvert at the interval of 10m, it was analyzed that unit subsurface discharge(q) of (a)20.2mm/day(110%), (b)32.8(178%), (c)34.6(188%) (d)27.5(149%) in the four types of non-excavation culvert installed at intervals of 5m under the condition of $ k=10^{-4}cm/s$ was much larger than the amount of (e)type 18.5(100%), existing excavation culvert installed at 10m interval. iii) Through the test construction, peak subsurface drainage discharge($q_p$) was 38.4mm/day, which is larger than the value of design criteria and confirmed that it satisfies the analysis results as well. iv) In particular, it was evaluated that (b)perforated pipe+horizontal mat(B50cm) are low cost, high efficiency subsurface drainage culvert type with sufficient drainage performance(178%).