• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.6
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• pp.479-487
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• 2020

A new double-pulse laser system that combines Raman and laser induced plasma spectroscopy (LIPS) in a single unit is proposed. The study attempts to enhance the laser induced plasma signals while simultaneously extracting the desired molecular signals from Raman spectroscopy. In low pressure conditions such as the lunar atmosphere, the measuring of plasma emission is hard because of the low electron density and short persistence time causing a rapid plasma expansion. Furthermore, in the integration of the detecting system aimed at space exploration, the minimization of laser system is important in terms of the payload mass. Simultaneous molecular and atomic detection that gave highly resolved spectral data at pressure below 0.07 torr is demonstrated amongst eight rock samples test. The plasma stacking produced from the double-pulse laser enhanced the signal intensity of calcium and oxygen lines in calcite matrix by twofold, compared to a conventional LIPS.

• Polymer(Korea)
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• v.38 no.6
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• pp.801-808
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• 2014

Ion diffusion and chemical binding to acrylic polymer were investigated in a solid film. The composition of acrylic monomers containing amino group and carboxylic acid was adjusted for rapid ion migration in the film. p-Methylred (PMR) and phenolphthalein derivatives were optically sensitive to the concentration of proton and hydroxyl anion, respectively and verified the ion migration through the film layers. A rapid proton migration was observed in the film of a high amino content. On the other hand, $OH^-$ migration occurred rapidly in a high content of carboxylic acid group. The proton migration occurred through the internal layer as well as surface layer of a film and was reversible during 50 repetition examination. Copper(II) ion migration was examined with a Rhodamine-containing polymer film. The light absorption and emission spectra of a Rhodamine-Cu complex showed the key contribution of carboxylic acid group to the Cu(II) migration in a film.

• Applied Chemistry for Engineering
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• v.32 no.1
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• pp.42-48
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• 2021

In this study, a sensor for detection of nitric oxide (NO) gas was developed using petroleum pitch-based activated carbon which was synthesized from pyrolysis fuel oil (PFO). Polyethylene terephthalate (PET) was added to increase molecular weight by stimulating a polymerization of components in PFO during the pitch synthesis process. The increase in the molecular weight of pitch contributed to the improvement of textural properties of activated carbon, such as the specific surface area and micropore volume. It also enhanced the sensitivity of NO gas sensor based on the activated carbon. In addition, the effect of PET addition during the pitch synthesis on the surface oxygen content and conductivity of activated carbon was investigated. Finally, the correlation of the sensitivity with physical properties of activated carbon was analyzed.

• Korean Journal of Food Science and Technology
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• v.43 no.3
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• pp.341-347
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• 2011

To develop a healthy functional food containing Rubus coreanus fruit (RCF) powder with different degrees of ripening, the composition, physicochemical properties, and antioxidant activity of native RCF during ripening were investigated and compared with Rubus occidentalis fruit (ROF). Ripened RCF was bright red in color, whereas ripened ROF was dull and dark red in color. The seeds of RCF were softer and smaller than those of ROF. Crude protein, crude lipid, and total sugar content of RCF powder increased with increased ripening time, whereas ash and total dietary fiber contents decreased with increased ripening time. Color differences increased with Increased ripening. Eighteen types of amino acids were analyzed from RCF, and glutamic acid had the highest content. RCF powder had the highest level of potassium and calcium and did not contain any hazardous metals. Mineral and organic acid contents decreased according to ripening.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.6
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• pp.792-797
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• 2008

The purpose of this study was to investigate the effects of adding various amounts of ingredients on the physicochemical and sensory characteristics of Bokbunja-jelly. The proximate composition of Bokbunja-jelly was 19.0% for the moisture and 0.8% for the crude protein. The Hunter L-values of Bokbunja-jelly prepared by adding 10 g RME or 120 g sucrose were higher than that of Bokbunja-jelly prepared by adding 20 g RME or 100 g sucrose. The Hunter b-values of Bokbunja-jelly prepared by adding 20 g RME or 120 g sucrose was higher than that of Bokbunja-jelly prepared by adding 10 g RME or 120 g sucrose. The hardness and chewiness were increased with decreasing Rubus coreanus Miquel extracts. According to the results of the sensory evaluation, no significant differences in flavor, sweetness, hardness, elasticity and overall qualities were found. According to the results of physicochemical properties and sensory evaluation, the optimal recipe for preparation of Bokbunja-jelly was determined to be 240 g water, 120 g sugar, 110 g glucose syrup, 4 g agar, 20 g Rubus coreanus Miquel extracts and 0.3 g Rubus coreanus Miquel flavor.

• Korean Journal of Plant Resources
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• v.34 no.2
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• pp.177-185
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• 2021

The purpose of this study was to compare the chemical properties of the bokbunja distributed in Korea with the content of the bioactive substance ellagic acid. The bokbunja was Rubus coreanus group and Rubus occidentalis group were compared, domestic bokbunja and import bokbunja were compared. In bokbunja, free sugar was 30.89 ± 0.7 mg/g of Rubus coreanus and 29.05 ± 0.87 mg/g of Rubus occidentalis. and 27.28 ± 7.4 mg/g of domestic bokbunja and 21.58 ± 6.73 mg/g of import bokbunja. The free amino acids was 4.50 ± 0.08 mg/g of Rubus coreanus and 5.05 ± 0.08 mg/g of Rubus occidentalis. and 4.13 ± 1.09 mg/g of domestic bokbunja and 3.75 ± 0.31 mg/g of import bokbunja. Validation of the ellagic acid method was confirmed by comparing the retention time and spectrum of the standard and extract using HPLC. The calibration curve (R²) showed linearity of 0.9999. As a result of analyzing the ellagic acid content of each extraction solvent, DMSO and methanol mixture extracts were high, and Rubus coreanus was 2.56 mg/g and Rubus occidentalis was 3.16 mg/g, which was not significantly different (p < 0.05) In addition, the ellagic acid content of domestic bokbunja and import bokbunja was 2.83 mg/g and 2.99 mg/g, which was not significantly different (p < 0.05).

• Journal of the Korean Chemical Society
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• v.35 no.4
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• pp.397-404
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• 1991

Nonchromophore compounds such as aliphatic acids, alcohols and tetraalkylammonium salts could be detected by indirect photometric detection on the revered-phase liquid chromatography. Benzyltriethylammonium bromide(BTEAB) was used as a detection reagent. Also, the retention mechanism and response of samples were investigated to the several factors such as pH, temperature, and concentration of MeOH as well as concentration of detection reagents in mobile phase. And some mixture of samples were able to be separated under optimum condition.

• Journal of the Korean Chemical Society
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• v.35 no.4
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• pp.350-354
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• 1991

Characteristics of a gas chromatographic detector using glow discharge as the ionization source was studied in helium flow. Discharge current greater than 10$_6$ A was observed from the electric field 400 V/mm for the electrode distance 1 mm. The discharge current of 0.1~0.3 mA could be used for the detection of organic compounds. Discharge current was almost constant for the helium flow rate greater than 10 ml/min, but the discharge was easily disappeared by an injection of a small amount of organic compound in the flow rate of 0~30 ml/min. From the decrement of the discharge current depend on several compounds, it was suggested that the sensitivity of the glow discharge ionization chromatographic detector is strongly influenced by the molecular weight of the compounds.

• The Korean Journal of Food And Nutrition
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• v.28 no.4
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• pp.728-736
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• 2015

Cronobacter species (Cronobacter spp.), previously known as Enterobacter sakazakii, are gram negative food borne pathogenic bacteria. They pose a very high risk of infection to neonates and immuno-compromised individuals and can affect the human central nervous system. Consequently, survivors often suffer from severe neurological impairment including hydrocephalus, quadriplegia, and developmental delays. Cronobacter spp. were not only isolated from plant food and products such as cereals, fruits, vegetables, legume products, herbs, and spices but also from animal source foods such as milk, meat, fish, and products made from these foods. Therefore, rapid detection of Cronobacter spp. is essential for food safety. Many detection methods have been developed since the Cronobacter spp. were first reported. However, the development of more rapid, sensitive, and easy-to-use detection methods for the Cronobacter spp. is required. In this review, our aim was to study and compare the available detection methods for Cronobacter spp., including culture-based, molecular biology-based, and immunology-based methods. This study will contribute to the development of new and rapid detection method for Cronobacter spp.

• The Korean Journal of Mycology
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• v.44 no.2
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• pp.103-107
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• 2016

To establish a rapid and accurate detection of Phytophthora pinifolia, which is a quarantine pathogenic fungus in Korea, a species-specific primer was developed based on the ras-related protein (Ypt1) gene. Species-specific primer based on the DNA sequences of Ypt1 gene amplified 193 bp polymerase chain reaction (PCR) product for P. pinifolia. The primer pair yielded the predicted PCR product size exactly in testing with target pathogen DNAs, but not from the other 10 species of Phytophthora and 14 species of other phytopathogenic fungi. The primer pair also showed only the species-specific amplification curve on realtime PCR on target pathogen DNA. The detection sensitivity of real time PCR using species-specific primer pair was 10 to 100 times higher than conventional PCR, with 1 to $10pg/{\mu}L$.