• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.4
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• pp.359-368
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• 2008

Black soybean has been widely utilized as foods and oriental medicinal materials. The pigmentation in the seed coat of black soybean is due to accumulate anthocyanins in the epidermis palisade layer. The anthocyanins of black soybean seed coat are considered as a parameter of quality evaluation of black soybean. Therefore, the purpose of this study was to investigate the most suitable HPLC condition for simultaneous determination of anthocyanins in black soybean seed coats extracts. The efficient HPLC analytical condition of D3G, C3G, and Pt3G contained extracts of black soybean seed coats was developed. The gradient elution employed a $250\;mm\;{\times}\;4.6\;mm$ i.d. YMC-pak ODS-AM 303 column. The gradient system was used two mobile phases. A gradient elution was performed with mobile phase A, consisting of 5% aqueous formic acid, and mobile phase B, comprising 5% formic acid - acetonitrile, and delivered at a flow rate of 0.7 mL/min as follows: $0{\sim}35\;min$, $90%\;A{\sim}60%\;A$; 36 min, 90% A; 46 min, 90% A. The UV-VIS. detection wavelength was set at 520 nm. The limit of detection (LOD) for D3G, C3G, and Pt3G were under 10 ng/mL.

• Economic and Environmental Geology
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• v.44 no.3
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• pp.239-246
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• 2011

Groundwater in small islands is used as main water resource but the overuse of groundwater may cause seawater intrusion and temperature decrease in geothermal wells. This study aimed to characterize the hydrogeology of Maeum-ri area in Seokmo Island of Ganghwagun using long-term monitoring at groundwater wells and geothermal wells. In the monitoring period seasonal water level change, consistent drop or increase of water levels are not detected. The groundwater temperature about 10m below ground surface shows year cycle variation having two to five months difference with ambient temperature cycle. The storativity was calculated by tidal method. The storativity estimated by adapting tidal efficiency factor showed some larger values than that by using tidal time lag. The result suggested that the tidal method assuming several assumptions on aquifer condition may produce broad ranges but the calculated ranges at this application are reasonable. The similar shape of groundwater level change and tidal effects was observed at several wells clustered east-south-east direction which may implicate the distribution of vertical fracture system strongly related with groundwater flow channels. The applied methodology and study results will bc valuable to evaluate optimal pumping rate for the preservation of groundwater resources, and to manage geothermal development.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.74-74
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• 2010

One-dimensional nanosturctures such as nanowires and nanotube have been mainly proposed as important components of nano-electronic devices and are expected to play an integral part in design and construction of these devices. Silicon carbide(SiC) is one of a promising wide bandgap semiconductor that exhibits extraordinary properties, such as higher thermal conductivity, mechanical and chemical stability than silicon. Therefore, the synthesis of SiC-based nanowires(NWs) open a possibility for developing a potential application in nano-electronic devices which have to work under harsh environment. In this study, one-dimensional nanowires(NWs) of cubic phase silicon carbide($\beta$-SiC) were efficiently produced by thermal chemical vapor deposition(T-CVD) synthesis of mixtures containing Si powders and hydrocarbon in a alumina boat about $T\;=\;1400^{\circ}C$ SEM images are shown that the temperature below $1300^{\circ}C$ is not enough to synthesis the SiC NWs due to insufficient thermal energy for melting of Si Powder and decomposition of methane gas. However, the SiC NWs are produced over $1300^{\circ}C$ and the most efficient temperature for growth of SiC NWs is about $1400^{\circ}C$ with an average diameter range between 50 ~ 150 nm. Raman spectra revealed the crystal form of the synthesized SiC NWs is a cubic phase. Two distinct peaks at 795 and $970\;cm^{-1}$ over $1400^{\circ}C$ represent the TO and LO mode of the bulk $\beta$-SiC, respectively. In XRD spectra, this result was also verified with the strongest (111) peaks at $2{\theta}=35.7^{\circ}$, which is very close to (111) plane peak position of 3C-SiC over $1400 ^{\circ}C$ TEM images are represented to two typical $\beta$-SiC NWs structures. One is shown the defect-free $\beta$-SiC nanowire with a (111) interplane distance with 0.25 nm, and the other is the stacking-faulted $\beta$-SiC nanowire. Two SiC nanowires are covered with $SiO_2$ layer with a thickness of less 2 nm. Moreover, by changing the flow rate of methane gas, the 300 sccm is the optimal condition for synthesis of a large amount of $\beta$-SiC NWs.

• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.1076-1084
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• 2017

For analyzing the qualitative and quantitative analysis of fuel marker in petroleum products, the applicability of HPLC was studied. For the qualitative analysis of fuel marker in kerosene and automotive diesel, optimal analytical conditions(ratio of mobile phase solvent, flow rate, etc) in HPLC were selected and calibration curve for quantitative analysis of fuel marker was prepared based on the result of qualitative analysis. In particular, the correlation coefficient of calibration curve in kerosene and automotive diesel was shown to be 0.999 in a certain concentration range and it could be applied to the quantitative analysis. The results of analysis using the UV/Vis spectrometer, which is the current analysis method of fuel marker, were compared with the analysis results using the HPLC. The kerosene showed a low deviation of about 7 % and the automotive diesel showed a somewhat large deviation of about 20 %.

• Journal of the Korean Society of School Health
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• v.20 no.1
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• pp.91-101
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• 2007

Purpose: The present study intended to reveal the association between the physique of adolescent women and dysmenorrhea, and the factors related to the frequency of dysmenorrhea. Methods: The study subjects included 511 girls of a women's high school in Daejeon city and they were, during the period of March 1st through April 30th, 2005, given self-administered questionnaires about frequency of menstruation, age, physique, exercise, and such menstruation-related items as age of menarche, menstrual period and days, and amount. Results: As with the frequency of dysmenorrhea, 38.4% experienced it 「always」, 44.6% 「occasionally」, and 17.0% 「almost scarcely」, and those with dysmenorrhea accounted for 83.0% of the subjects. The frequency of dysmenorrhea was not significant difference according to the BMI and HPI. However, the lower the age of menarche and the greater the amount of menstrual flow, the more frequent dysmenorrhea. The symptoms of dysmenorrhea included the highest frequency of low back pain(68.5%) and it was followed by abdominal pain(65.9%), sensibility(54.0%), fatigue(51.7%), and nervousness(49.5%). These accompanied symptoms tended to be worse as the frequency of dysmenorrhea increased. The multiple logistic regression analysis revealed that the relative risk of frequency of dysmenorrhea is 2.2 times in age of 14, by a standard age of 15 as menarchial age, 2.2 in 13, and 3.1 in below 12. The menstrual days was 3.0 times in both below 2 days and over 8 days with the standard days of 3-7 days. The menstrual amount was 1.9 times in the group with a greater amount of menstrual bleeding and 1.5 times in the group with a less amount than the normal group, respectively. Conclusion: The above results suggest that the rate of experiencing dysmenorrhea was up to 83.0% and 38.4% from these had dysmenorrhea upon every menstruation. It is thought that dysmenorrhea could be a great disadvantage sufficient to impair optimal health to a larger body of school girls. Further, for quality of life, it is required that more fundamental strategies instead of pain killers or others for palliation of dysmenorrhea would be established among adolescents.

• Journal of the Korean Society of Radiology
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• v.15 no.7
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• pp.999-1005
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• 2021

The object of this research is CS, which increases resolution while shortening inspection time, is applied to MRA to compare the quality of images for SENSE and CS techniques and to evaluate SNR and CNR to find out the optimal techniques and to provide them as clinical basic data based on this information. Data were analyzed on 32 patients who performed TOF MRA tests at a university hospital in Chung cheong-do (15 males, 17 females), ICA stenosis:10, M1 Aneurysm:10, and average age 53 ± 4.15). In the inspection, the inspection equipment was Ingenia CX 3.0T, Archieva 3.0T, and 32 channel head coil and 3D gradient echo as a method for equipment data. SNR and CNR of each image were measured by quantitative analysis, and the quality of the image was evaluated by dividing the observer's observation into 5 grades for qualitative evaluation. Imaging evaluation is described as being significant when the p-value is 0.05 or less when the paired T-test and Wilcoxon test are performed. Quantitative analysis of SNR and CNR in TOF MRA images Compared to the SENSE method, the CS method is a method measurement method (p <0.05). As an observer's evaluation, the sharpness of blood vessels: CS (4.45 ± 0.41), overall image quality: CS (4.77 ± 0.18), background suppression of images: CS (4.57 ± 0.18) all resulted in high CS technique (p = 0.000). In conclusion, the Compressed SENSE TOF MRA technique shows superior results when comparing and evaluating the SENSE and Compressed SENSE techniques in increased flow rate magnetic resonance angiography. The results are thought to be the clinical basis material in the 3D TOF MRA examination for brain disease.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.31 no.1
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• pp.1-7
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• 2021

ε-Ga2O3, a metastable phase of Ga2O3, has excellent compatibility with substrates having a hexagonal structure or a quasi-hexagonal structure, so that a film having a relatively lower surface roughness and defect density than β-Ga2O3 can be obtained easily. Accordingly, we attempted to fabricate a high-quality β-Ga2O3 film with a low surface roughness and defect density using the property of phase transition to β-Ga2O3 when ε-Ga2O3 is annealed at a high temperature. For this, the growth of high-quality ε-Ga2O3 films must be preceded. In this study, the optimal flow rate was investigated by analyzing the structural and morphological characteristics of the ε-Ga2O3 film according to the supplied precursor ratio. In addition, the annealing condition and the effect of β-Ga2O3 mixed in the ε-Ga2O3 film on the crystallinity of β-Ga2O3 after phase transition were also investigated.

• Journal of Life Science
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• v.32 no.1
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• pp.36-43
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• 2022

Mucosal immunity is a well-designed defense system that builds precise and dynamic relationships against pathogens, and the gastrointestinal tract is the most important organ with this system, acting as a guardian at the forefront of its activity. Salmonella spp. cause food poisoning, entering the body orally and mainly invading the Peyer's patches of the small intestine. Although Salmonella strains share similar mechanisms for inducing innate immunity, different serotypes may have different effects on the intestinal mucosa due to host specificities and pathogenicity. In this study, we evaluated the effects of Salmonella enteritidis infections in mouse intestine and observed significantly reduced dose-dependent survival rates in a challenge test. Flow cytometry data showed no significant differences in intestinal immune cell populations, although histology indicated increased mucin production and decreased goblet cell counts in the Salmonella-treated groups. Furthermore, Claudin expression was significantly decreased in the samples with Salmonella. To investigate the relationship between S. enteritidis infection and inflammatory response, dextran sodium sulfate (DSS) was administered after infection and the results indicate lower survival rate after DSS treatment. In conclusion, we were able to identify the optimal concentration of S. enteritidis to modulate the intestinal mucosal immunity of mice and inflammatory response.

• Clean Technology
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• v.28 no.4
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• pp.331-338
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• 2022

The objective of this study is to prepare bead-type and pellet-type Pt (1 wt%)/Kieselguhr catalysts as hydrogenation catalysts for the polycyclic aromatic hydrocarbons (PAHs) included in pyrolysis fuel oil (PFO). The optimal reaction temperature to maximize the yield of saturated cyclic hydrocarbons during the PFO-cut hydrogenation reaction in a trickle bed reactor was determined to be 250 ℃. A hydrogen/PFO-cut flow rate ratio of 1800 was found to maximize 1-ring saturated cyclic compounds. The yield of saturated cyclic compound increased as the space velocity (LHSV) of PFO-cut decreased. The difference in hydrogenation reaction performance between the pellet catalyst and the bead catalyst was negligible. However, the catalyst impregnated by Pt after molding the Kieselguhr support (AI catalyst) showed higher hydrogenation activity than the catalyst molded after Pt impregnation on the Kieselguhr powder (BI catalyst), which was a common phenomenon in both the pellet catalysts and bead catalysts. This may be due to a higher number of active sites over the AI catalyst compared to the BI catalyst. It was confirmed that the pellet catalyst prepared by the AI method had the best reaction activity of the prepared catalysts in this study. The majority of the PFO-cut hydrogenation products were cyclic hydrocarbons ranging from C₈ to C₁₅, and C₁₁ cyclic hydrocarbons had the highest distribution. It was confirmed that both a cracking reaction and hydrogenation occurred, which shifted the carbon number distribution towards light hydrocarbons.

• Applied Chemistry for Engineering
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• v.34 no.3
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• pp.307-312
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• 2023

In this study, a catalytic oxidation-heat recovery system was designed that can remove unreacted with a concentration of about 1% to 6% in the exhaust gas of hydrogen fuel cells and recover heat to ensure safety in the hydrogen economy. The safety system was devised by filling hydrogen oxidation catalysts at room temperature that can remove unreacted hydrogen without any energy source, and an exhaust-heat recovery device was integrated to efficiently recover the heat released from the oxidation reaction. Through CFD analysis, variations in pressure and fluid within the system were shown depending on the filling conditions of the hydrogen oxidation system. In addition, it was found that waste heat could be recovered by optimizing the temperature of the exhaust gas, flow rate, and pressure conditions within the heat recovery system and securing hot water above 40 ℃ by utilizing the exhaust gas oxidation heat source above 300 ℃. Through this study, it was possible to confirm the potential of utilizing hydrogen processes, which are applied in small to medium-sized systems such as hydrogen fuel cells, as a safety system by evaluating them at a pilot scale. Additionally, it could be a safety guideline for responding to unexpected hydrogen safety accidents through further pilot-scale studies.