• Korean Journal of Crystallography
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• v.6 no.1
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• pp.43-48
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• 1995

The crystal structure of P-toluenesulfonanilide, C13H13NO2S is monoclinic, space group P21/c, a=8.777(1)Å, b=9.784(2)Å, c=15.139(2)Å, β=99.00(1)°, Z=4, V=1284.0(6)Å3, Dc=1.28g/cm33, λ(Mo-Kα)=0.71069Å, μ=2.3cm-1, F(000)=520, Temperature : 293±3K, R=0.038 for 711 Fo<3.0σ unique observed reflection. The structure was determuned by direct method and refined by full-matrix least squares refinement. Two benzene rings have the dihedral angle of 68.4°. Moleculs are accumulated according to the c axis with two fold screw and contacted by van der Walls force.

• Environmental Engineering Research
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• v.18 no.1
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• pp.29-35
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• 2013

This study noted that the actual mechanism of N-nitrosodimethylamine (NDMA) photodecomposition in the presence of $H_2O_2$ is missing from the previous works. This study investigated a key unknown reactive species (URS) enhanced by the addition of $H_2O_2$ during the photolysis of NDMA with $H_2O_2$, not hydroxyl radicals. In order to provide experimental evidences in support of URS formation, we have mainly used p-nitrosodimethylaniline, methanol, and benzoic acid as well-known probes of ${\cdot}OH$ in this study. Both loss of PNDA and formation of hydroxybenzoic acids were dependent on NDMA concentrations during the photolysis in a constant concentration of $H_2O_2$. In particular, competition kinetics showed that the relative reactivity of an URS was at least identical with ${\cdot}OH$-like reactivity. In addition, the decay of NDMA was estimated to be about 65% by the direct UV light and about 35% by the reactive species or URS generated through the photolysis of NDMA and $H_2O_2$. Therefore, our data suggest that a highly oxidizing URS is formed in the photolysis of NDMA with $H_2O_2$, which could be peroxynitrite ($ONOO^-$) as a potent oxidant by itself as well as a source of ${\cdot}OH$.

• The Plant Pathology Journal
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• v.15 no.5
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• pp.280-286
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• 1999

Lichen-forming (LFF) or lichenicolous fungi (LCF) were isolated from the lichens collected at‘Backwoon’mountain area,‘Chiri’mountain area and‘Sorok’island in the southern regions of Korea and were screened for antagonistic efficacy against several phyto-pathogenic fungi. Symbiotic algae-free LFF and LCF were isolated by the following methods: I) discharged spores (ascospores), II) macerated thallus suspension and III) direct use of thallus fragments. Among 58 isolates obtained from 34 lichens, 8 isolates showed antifungal activity against Rhizoctonia solani. Antifungal activities of the strongest antagonistic isolate (LB9810) originated from the thallus of Parmelia quercina lichen were evaluated against 15 phyto-pathogenic fungi. When crude methanol extract of mycelia of the LB8910 isolate was employed at the rate of 0.5% (v/w), fungal growth of Magnaporthe grisea and Rhizoctonia solani was severly and Rhizoctonia solani was severly inhibited as much as approximately 60% compared to control. Growth of various food-borne same extract. The extract was successively partitioned with n-hexane, ethyl acetate and n-butanol. n-Hexane fraction displayed the strongest antifungal activities against R. solani. The LB9810 isolate was finally identified as Fusarium equiseti (Corda) Sacc., which has not been reported as LFF or LCF yet. Therefore, it is very likely that F. equiseti isolated it the study was originated from the contaminants associated with thallus fragments rather than from LFF or LCF.

• Journal of Korean Vacuum Science & Technology
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• v.2 no.2
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• pp.63-77
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• 1998

The oxidation of NiAl(110) was investigated in the temperature regime between 300K and 1300 K using LEED (low energy electron diffraction), TPD (temperature programmed desorption) and HREELS (high resolution electron energy loss spectroscopy). The adsorption of N2O and O2 up to reconstructions. Stepwise annealing of the oxygen-saturated sample from 600 K to 1300K in UHV (ultra-high vacuum,) results in firstly the onset of randomly oriented then finally fairly well-ordered. 5 ${\AA}$ Al2O3 film with quasi-hexagonal periodicity. Ordered thicker oxide films of 18-30 ${\AA}$ seem to be grown on this interfacial oxide layer by direct oxidation of sample at elevated temperature between 1150 and 1300 K because of the LEED pattern consisting of new broad hexagonal spots and the previous 5 ${\AA}$ spots. Although the periodicity of surface oxygen arrays shows no significant change from an hexagonal close-packing, the O-O distance changes from ∼3.0 ${\AA}$ film to ∼2.9 ${\AA}$ for thicker oxides. with the appearance of Auger parameter, for the 5${\AA}$ film can be described better as an interfacial oxide layer. The observation of three symmetric phonon peaks can be also a supporting evidence for this phase assignment since thicker oxide films on the Same Ni2Al3(110) show somewhat different phonon structure much closer to that of the ${\gamma}$-Al2O3. The adsorption/desorption of methanol further proves the preparation of less-defective and/or oxygen-terminated Al2O3 films showing ordered phase transitions with the change of oxide thickness between 5 ${\AA}$ to 30 ${\AA}$.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.403-403
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• 2010

The Pt-Ni alloy is an electro-catalyst of interest in the low temperature direct methanol fuel cells(DMFCs). It has been already reported that the Pt-Ni alloy catalysts may even have enhanced activity compared to pure platinum catalyst, depending on how the surfaces are prepared. The order-disorder transition in bimetallic alloy such as $\beta$-CuZn, Cu3Au, and CuAu have been investigated greatly by x-ray diffraction. After annealing the bimetallic alloy, the crystal structure changes as observed in the order-disorder transition of Cu3Au which changes from the face centered cubic to a simple cubic structure. Pt-Ni bimetallic alloy has been already reported to have the face centered cubic structure. However, in nano-scale Pt-Ni bimetallic alloy crystals the crystal structures changes to a simple cubic structure. In this experiment, we have studied the order-disorder transition in Pt-Ni bimetallic nanocrystals. Pt/Ni thin films were deposited on sapphire(0001) substrates by e-beam evaporator and then Pt-Ni alloy were formed by RTA at 500, 600, and $700^{\circ}C$ in a vacuum environment and Pt-Ni nano particles were formed by RTA at $1059^{\circ}C$ in a vacuum environment. We measured the structure of Pt-Ni bimetallic alloy films using synchrotron x-ray diffraction and SEM.

• Nutrition Research and Practice
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• v.15 no.5
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• pp.568-578
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• 2021

BACKGROUND/OBJECTIVES: Psidium guajava L. (guava) leaves have been shown to exhibit hypoglycemic and antidiabetic effects in rodents. This study investigated the effects of guava leaf extract on adipogenesis, glucose uptake, and lipolysis of adipocytes to examine whether the antidiabetic properties are mediated through direct effects on adipocytes. MATERIALS/METHODS: 3T3-L1 cells were treated with 25, 50, 100 ㎍/mL of methanol extract from guava leaf extract (GLE) or 0.1% dimethyl sulfoxide as a control. Lipid accumulation was evaluated with Oil Red O Staining and AdipoRed assay. Immunoblotting was performed to measure the expression of adipogenic transcription factors, fatty acid synthase (FAS), and AMP-activated protein kinase (AMPK). Glucose uptake under basal or insulin-stimulated condition was measured using a glucose analog 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino]-2-deoxy-D-glucose. Lipolysis from fully differentiated adipocytes was measured by free fatty acids release into the culture medium in the presence or absence of epinephrine. RESULTS: Oil Red O staining and AdipoRed assay have shown that GLE treatment reduced lipid accumulation during adipocyte differentiation. Mitotic clonal expansion, an early essential event for adipocyte differentiation, was inhibited by GLE treatment. GLE inhibited the expression of transcription factors involved in adipocyte differentiation, such as peroxisome proliferator-activated receptor 𝛄 (PPAR𝛄), CCAAT/enhancer-binding protein α (C/EBPα), and sterol regulatory element-binding protein-1c (SREBP-1c). FAS expression was also decreased while the phosphorylation of AMPK was increased by GLE treatment. In addition, GLE increased insulin-induced glucose uptake into adipocytes. In lipid-filled mature adipocytes, GLE enhanced epinephrine-induced lipolysis but reduced basal lipolysis dose-dependently. CONCLUSIONS: The results show that GLE inhibits adipogenesis and improves adipocyte function by reducing basal lipolysis and increasing insulin-stimulated glucose uptake in adipocytes, which can be partly associated with antidiabetic effects of guava leaves.

• Clean Technology
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• v.15 no.4
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• pp.287-294
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• 2009

In order to separate the fuel-grade DME from the product of a direct DME synthesise reaction, containing 19~20% of DME, an absorption column and a purification column were employed. In the DME absorption column, the flow rate of the methanol required to recover more than 99% of DME at 50 bar was estimated by the correlation obtained from the lab-scale experiments. In the DME purification column, the maximum DME recovery of 98.2% could be obtained even from the side stream at the 3rd stage above the feed stage, since the feed stream originated from the product of the absorption column had already contained a large amount of DME (20~30 mol%) and only a small amount of light products such as $CO_2$ and $N_2$ (5~10 mol%).

• Transactions of the Korean hydrogen and new energy society
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• v.35 no.2
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• pp.140-145
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• 2024

High temperature co-electrolysis of H₂O-CO₂ mixtures using solid oxide cells has attracted attention as promising CO₂ utilization technology for production of syngas (H₂/CO), feedstock for E-fuel synthesis. For direct supply to E-fuel production such as hydrocarbon and methanol, the outlet gas ratio (H₂/CO/CO₂) of co-electrolysis should be controlled. In this work, current voltage characteristic test and product gas analysis were carried out under various reaction conditions which could attain proper syngas ratio.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.2
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• pp.143-148
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• 1992

The antimutagenic effects of green-yellow vegetables toward aflatoxin B$_1$(AFB$_1$) and 4-nitroquinoline-1-ox-ide (4-NQO) using the Ames assay system with Salmonella typhimurium TA98 and TA100 were studied. Forty six to fifty percent of the methanol extracts of the vegetable samples inhibited the mutagenicity induced by AFB$_1$in TA98 and TA100. Perilla leaf, lettuce, broccoli, crown daisy, water dropwort, small water dropwort, red pepper, red pepper leaves, amaranth, spinach and radish root were significantly reduced the mutagenicity of AFB$_1$(p< 0.01). Whereas 25 out of 27 samples (93%) exhibited antimutagenicity toward a direct mutagen of 4-NQO (p< 0.01. 0.05). The samples which showed the strong antimutagenicity (>60%) were cabbage, kale, lettuce, broccoli, mustard leaf, green red pepper, green sweet pepper, spinach, amaranth, soybean sprout and immature pumpkin. The juices from the several samples also showed antimu-tagenic activity toward AFB$_1$. Cabbage, perilla leaf, small water dropwort and spinach reduced TAT100 revertants dose dependently in the range of 50-500$m\ell$/plate, however, cucumber and carrot showed little effect.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.618-624
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• 2020

A portable power supply system for soldiers must be able to supply electric energy corresponding to the power consumption of combat support troops, and have a carrying load in a range that does not impair the combatant's ability to execute operations. In particular, as the total required power of combat equipment increases with the advances in the future soldier system, a portable, lightweight power supply system with high efficiency is essential. A fuel cell has a high energy-to-weight density compared to lithium batteries, which are used mainly as a military power source system. Therefore, it is capable of miniaturization and lightweight, making active R&D to a portable power supply system. In this paper, the characteristics of the fuel cell applied as a portable power supply system, and the R&D trends of domestic and foreign military portable fuel cell systems were investigated. The current status of domestic technology compared to the level of foreign development was analyzed. In addition, future technology development plans are presented based on the consideration factors when developing a portable fuel cell (power supply stability, portability, and cost reduction) so that it can be used when establishing a plan on the development of a portable fuel cell system for the future soldier system.