• KSBB Journal
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• v.25 no.3
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• pp.289-296
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• 2010

Lectins are carbohydrate-binding and a cell-agglutinating proteins, and are concerted with a plants defence mechanism. In particular, chitin-binding lectins in locular fluid of cherry tomato fruit seemed to have a role in defending plants against fungi. The antifungal activity using lectin isolated from locular fluid of cherry tomato fruit was measured in the plant pathogen Cladosporium cucumerinum, Monosporascus cannonballus, Fusarium oxysporum, and Rhizoctonia solani. Amoung the four strains, a potent antifungal activity was detected in Cladosporium cucumerinum and Monosporascus cannonballus, not in Fusarium oxysporum, and Rhizoctonia solani. The molecular weight of this lectin isolated as double protein bands by SDS-PAGE was calculated to be 87 kDa and 47 kDa from the relative mobilities compared with those of reference molecular weight markers. The isolated lectin agglutinated human red blood cells (A, B, AB, O) treated with trypsin, and the most activity was found at B. The optimal temperature of isolated lectin was at $30^{\circ}C$. For the thermal stability, lectin was stable at $20-80^{\circ}C$. The optimal pH of this lectin was at 7.2, and showed complete loss below pH 9.0.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.3
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• pp.321-330
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• 2011

We experimentally investigated the effect of applied DC electric fields on the flame spread over polyethylene-coated electrical wire. The flame-spread rates over electrical wire with negative and positive DC electric fields from 0 to ${\pm}7$ kV were measured and analyzed. We compared the results for DC electric fields with previous results for AC electric fields. We explored whether or not various flame shapes could be obtained with DC electric fields and the main reason for the flame-spread acceleration, particularly at the end of the electrical wire, for AC electric fields. We found that DC electric fields do not significantly affect the flame-spread rates. However, the flame shape is mildly altered by the ionic wind effect even for DC electric fields. The flame-spread rate is relevant to the flame shape and the slanted direction in spite of the mild impact. A possible explanation for the flame spread is given by a thermal-balance mechanism and fuel-vapor jet.

• Journal of Sensor Science and Technology
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• v.29 no.2
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• pp.93-99
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• 2020

A colorimetric paper sensor was used to detect volatile nitrogen-containing compounds emitted from spoiled salmon filets to determine their freshness. The sensing mechanism was based on acid-base reactions between acidic pH-indicating dyes and basic volatile ammonia and amines. A sensing layer was simply fabricated by drop-casting a dye solution of bromocresol green (BCG) on a polyvinylidene fluoride substrate, and its color-change response was enhanced by optimizing the amounts of additive chemicals, such as polyethylene glycol, p-toluene sulfonic acid, and graphene oxide in the dye solution. To avoid the adverse effects of water vapor, both faces of the sensing layer were enclosed by using a polyethylene terephthalate film and a gas-permeable microporous polytetrafluoroethylene sheet, respectively. When exposed to basic gas analytes, the paper-like sensor distinctly exhibited a color change from initially yellow, then to green, and finally to blue due to the deprotonation of BCG via the Brønsted acid-base reaction. The use of ammonia analyte as a test gas confirmed that the sensing performance of the optimized sensor was reversible and excellent (detection time of < 15 min, sensitive naked-eye detection at 0.25 ppm, good selectivity to common volatile organic gases, and good stability against thermal stress). Finally, the coloration intensity of the sensor was quantified as a function of the storage time of the salmon filet at 28℃ to evaluate its usefulness in monitoring of the food freshness with the measurement of the total viable count (TVC) of microorganisms in the food. The TVC value increased from 3.2 × 10⁵ to 3.1 × 10⁹ cfu/g in 28 h and then became stable, whereas the sensor response abruptly changed in the first 8 h and slightly increased thereafter. This result suggests that the colorimetric response could be used as an indicator for evaluating the degree of decay of salmon induced by microorganisms.

• Economic and Environmental Geology
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• v.45 no.2
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• pp.79-88
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• 2012

The increased brightness and focused X-ray beams now available from laboratory X-ray sources facilitates a variety of powder diffraction experiments not practical using conventional in-house sources. Furthermore, the increased availability of 2-dimensional area detectors, along with implementation of improved software and customized sample environmental cells, makes possible new classes of in-situ and time-resolved diffraction experiments. These include phase transitions under variable pressure- and temperature conditions and ion-exchange reactions. Examples of in-situ and time-resolved studies which are presented here include: (1) time-resolved data to evaluate the kinetics and mechanism of ion exchange in mineral natrolite; (2) in-situ dehydration and thermal expansion behaviors of ion-exchanged natrolite; and (3) observations of the phases forming under controlled hydrostatic pressure conditions in ion-exchanged natrolite. Both the quantity and quality of the in-situ diffraction data are such to allow evaluation of the reaction pathway and Rietveld analysis on selected dataset. These laboratory-based in-situ studies will increase the predictability of the follow-up experiments at more specialized beamlines at the synchrotron.

• Applied Chemistry for Engineering
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• v.19 no.1
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• pp.17-26
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• 2008

With the effectuation of Kyoto Protocol on the United Nations Framework Convention on the Climate Change, the emission reduction of greenhouse gases became an urgent issue and has been competitively secured among countries as the form of certificates through clean development mechanism (CDM) or joint implementation (JI). Nitrous oxide ($N_2O$) is one of the major greenhouse gases along with carbon dioxide ($CO_2$) and methane ($CH_4$) having warming potential 310 times that of carbon dioxide and chemically very stable in the atmosphere to give a life time of more than 120 years so that it reaches to the stratosphere to act as an ozone depleting substance. $N_2O$ hardly decomposes and thus, besides to the adoption of thermal decomposition at high temperature, selective catalytic reduction methods are usually used at temperatures over $400^{\circ}C$ in which the presence of NOx acts as a major impeding material in the decomposition process. In this article, the sources of various $N_2O$ generation, catalytic reduction processes and the status and trends of emission trade with CDM projects for greenhouse gas reduction are summarized and discussed on a condensed basis.

• Applied Chemistry for Engineering
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• v.26 no.2
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• pp.145-153
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• 2015

$Cr_2O_3/AP$ (ammonium perchlorate) energetic composites were prepared by a method of solvent/anti-solvent. XRD analysis revealed that the crystalline structure of AP in $Cr_2O_3/AP$ composites is the same as that of pure AP. SEM photomicrograph shows that an average size of cuboid $Cr_2O_3/AP$ composites is approximately $2.5{\mu}m$. TGA analysis shows that the addition of submicron $Cr_2O_3$ particles into AP lowers the HTD (high-temperature decomposition) compared to that of neat AP and the activation energy of the $Cr_2O_3/AP$ composites was calculated by the isoconversional Starlink method. Considering changes in the activation energy, the decomposition reaction mechanism of AP was suggested as follows; the decomposition with the formation of nucleation sites renders formation of porous structure in the composites up to conversion of about 0.25 and after further conversion of over 0.3, it seems that decomposition reaction vigorously takes place rather than sublimation of AP.

• Journal of the Korean Vacuum Society
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• v.18 no.3
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• pp.229-235
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• 2009

Millimeter-scale aligned arrays of thin-multiwalled carbon nanotube (t-MWCNT) on layered Si substrates have been synthesized by oxygen-assisted microwave plasma chemical vapor deposition (MPCVD). We have succeeded in growth of vertically aligned MWCNTs up to 2.7 mm in height for 150 min. The effect of $O_2$ and water vapour on growth rate was systematically investigated. In the case of $O_2$ gas, the growth rate was ${\sim}22{\mu}m/min$, which is outstanding growth rate comparing with those of conventional thermal CVD (TCVD). Scanning electron microscope (SEM), energy-dispersive spectroscopy (EDS), and Raman spectroscopy were used to analyze the CNT morphology, composition and growth mechanism. The role of $O_2$ gas during the CNT growth was discussed on.

• Resources Recycling
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• v.19 no.3
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• pp.52-61
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• 2010

In general, the waste concrete is simply crushed and reused as a recycled aggregate at a low value application such as back filling material. It because that the quality of recycled aggregate is lower than one of natural aggregate due to the insufficient liberation of aggregate and cement mortar. So in this study, the liberation characteristics of liberation of aggregate and cement mortar is analyzed to investigate the limitation of conventional crushing stage at waste concrete processing circuit. In this process, thermal treatment method is evaluated for the enhancement of liberation. From test results, the preferential breakage along the grain boundary is not accomplished by the conventional crushers. It leads a low quality of recycled aggregate and a fracture of aggregate. To solve these problems, gentle breakage is used as a breakage mechanism to induce preferential breakage along the grain boundary. The recycled aggregate produced from the free fall test, which adopts a gentle breakage, shows a better liberation characteristics and a higher quality.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.1
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• pp.26-34
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• 1982

The East China Sea and the Yellow Sea are abundant in nutritions because of river inflows and are important as the nursery and spawning grounds of demersal and pelagic fishes. The remarkable thermal front between the Yellow Sea Bottom Cold Water and the Tsushima Warm Current is formed in this region, and the fluctuation of this front may affect the variation of the yellow croaker fishing ground. To investigate the mechanism of the yellow croaker fishing ground, the distribution ana seasonal change of the fishing ground are examined by using catch of stow net fishery (Fisheries Research and Development Agency, 1970-1979) and the water temperature data (Japan Hydrographic Association, 1978). The main fishing ground of yellow croaker was nine sea areas (rectangle of 30' latitude by 30' longitude) located at 40-150 nautical miles west and southwest of Jeju Island, the area of which occupies no more than $11\%$ of all fishing grounds, and it appeared that about $70\%$ of total catch of ten years was concentrated in this area. The main fishing periods were from March to May and September to October. The coefficients of variation of the catch for the main fishing ground were from 0.8 to 2.1 and the condition of all fishing grounds was generally unstable. The mean CPUE was 27kg/haul at the main fishing ground, while it was the largest on boundary area of the Yellow Sea Bottom Cold Water. It was found that the seasonal movement of fishing ground is related to the expansion and reduction of the Yellow Sea Bottom Cold Water ($10^{\circ}C$).

• Composites Research
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• v.18 no.2
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• pp.20-29
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• 2005

To evaluate the flexural deformation and strength of composite motor case above the glass transition temperature$(T_g),\;170^{\circ}C$, of resin material, a finite element analysis(FEA) model in which material non-linearity and progressive failure mode were considered was proposed. The laminated flexural specimens which have the same lay-up and thickness as the composite motor case were tested by 4-point bending test to verify the validity of FEA model. Also. mechanical properties in high temperature were evaluated to obtain the input values for FEA. Because the material properties related to resin material were highly deteriorated in the temperature range beyond $T_g$, the flexural stiffness and strength of laminated flexural specimen in $200^{\circ}C$ were degraded by also $70\%\;and\;80\%$ in comparison with normal temperature results. Above $T_g$, the failure mode was changed from progressive failure mode initiated by matrix cracking at $90^{\circ}$ ply in bottom side and terminated by delamination at the center line of specimen to fiber compressive breakage mode at top side. From stress analysis, the progressive failure mechanism was well verified and the predicted bending stiffness and strength showed a good agreement with the test results.