• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.6
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• pp.567-573
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• 2015

This paper aims to evaluate the variation in the mechanical properties of carbon/epoxy composites under in situ low- and high-temperature environments. In situ low- and high-temperature environments were simulated with temperature ranging from $-40^{\circ}C$ to $220^{\circ}C$ using an environmental chamber and furnace. The variation in the mechanical properties of the composites was measured for longitudinal and transverse tensile properties, in-plane shear properties and interlaminar shear strength. Under the low temperature of $-40^{\circ}C$, all mechanical properties increased moderately compared to the baseline properties measured at room temperature. The changes in the longitudinal tensile properties decreased moderately with increasing temperature. However, transverse tensile properties, in-plane shear properties and interlaminar shear strength each showed a significant drop due to the glass transition behavior of the matrix after $140^{\circ}C$. Notably, the tensile property value near $100^{\circ}C$ increased compared to baseline property value, which was an unusual occurrence. This behavior was a direct result of post-curing of the epoxy resin due to its exposure to high temperature.

• Journal of Mushroom
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• v.18 no.3
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• pp.254-259
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• 2020

Grifola frondosa is a promising new kind of cultivated mushroom owing to its excellent taste and functionality. However, more research is required to determine its value. In this study, the effects of pretreating Grifola frondosa tea by drying, steaming, and warming, on quality characteristics and antioxidant activities were analyzed. There was no difference in sugar, soluble solid, and nitrogen content between dried and steamed tea. The color of the warm pretreated tea was the darkest, and the amino acid content was 462.9 mg/L, which was 1.8 times higher than that of the other pretreatments. Moreover, the warm pretreated tea had the highest total polyphenol and flavonoid content, 14.6 mg/g and 2.2 mg/g, respectively. DPPH and ABTS radical scavenging activities significantly increased with the increase of phenolic compounds. Warming pre-treatment slightly increased the taste preference to 7.0. In conclusion, warming Grifola frondosa before drying was confirmed to improve the extraction of nutrients, antioxidants, and taste preference.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.8
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• pp.913-920
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• 2011

We describe the evaluation of the fatigue life and strength of a lightweight railway bogie frame made of glass fiber/epoxy 4-harness satin-woven composites. To obtain the S-N curve for the evaluation of the fatigue characteristics of the composite bogie frame, we performed a tension-compression fatigue test for composite specimens with different stacking sequences of the warp direction, fill direction, and $0^{\circ}/90^^{\circ}$ direction. We used a stress ratio (R) of -1, a frequency of 5 Hz, and an endurance limit of $10^7$. The fatigue strength of the composite bogie frame was evaluated by a Goodman diagram according to JIS E 4207. The results show that the fatigue life and strength of the lightweight composite bogie satisfy the requirements of JIS E 4207. Given its weight, its performance was better than that of a conventional metal bogie frame based on an SM490A steel material.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.8
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• pp.1114-1121
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• 2016

This study investigated the food components and antioxidant activities of dried Jerusalem artichoke (Helianthus tuberosus L.) with white and purple colors. For the proximate composition of dried Jerusalem artichoke, regardless of color, carbohydrate content was highest, followed by crude protein, ash, and moisture contents, and breed-specific differences were not detected. The highest mineral content of dried Jerusalem artichoke was potassium, followed by calcium, magnesium, sodium, and iron. The major minerals of white color sample were calcium, magnesium, and zinc, whereas those of the purple color sample were potassium, sodium, copper, and manganese, and no significant differences between the samples were detected. The main amino acid of dried Jerusalem artichoke was arginine, regardless of color, followed by asparagine, aspartic acid, and ${\gamma}-amino-n-butyric$ acid in order. Cysteine, leucine, and tyrosine were significantly (P<0.05) more abundant in the purple color sample than in the white color sample. In contrast, phosphoethanolamine was significantly (P<0.05) higher in the white color sample than in the purple color sample. Antioxidant activity was higher in the purple color sample than in the white color sample for all activities except the 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) assay methodology. Ferric-reducing antioxidant power and oxygen radical absorbance capacity assays at low concentrations of extracts found no differences between the two samples, although the purple sample at high concentration showed relatively high antioxidant activities.

• Korean Journal of Microbiology
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• v.44 no.1
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• pp.74-79
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• 2008

The purpose of this study is to clone cgt gene from Paenibacillus sp. JB-13 and to overexpress the protein in E. coli. For this purpose, the cgt gene was amplified from Paenibacillus sp. JB-13 genomic DNA by PCR using degenerate oligonucleotide primers. The sequence analysis results showed that the cgt gene from Paenibacillus sp. JB-13 has 98% homology with the cgt gene of Bacillus sp. To overexpress the protein, the cgt gene was cloned into pEXP7 expression vector and transformed into E. coli. The production of CGTase by recombinant E. coli was optimized under following conditions: 0.5% glucose, 3.0% polypeptone, 0.3% $K_2HPO_4$, 0.5% NaCl, and 7.0 of initial pH, 2.0% of inoculum, $37^{\circ}C$ of culture temperature for 14 hr. And the optimal agitation was found at 0.1 vvm. The synthesis of 2-O-${\alpha}$-D-Glucopyranosyl L-Ascorbic acid (AA-2G) using the CGTase expressed in E. coli was identified as AA-2G by HPLC and HPLC confirmed that treating AA-2G made by cloned CGTase with ${\alpha}$-glucosidase substantially produced AA and glucose.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.5
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• pp.746-751
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• 2015

The quality characteristics of Oenothera biennis juice (OJ) fermented with various concentrations of sugar solutions (50, 60, and $70^{\circ}Brix$) and at different temperatures (20 and $30^{\circ}C$) were investigated. The sugar concentration and pH of fermented OJ decreased during fermentation and more rapidly decreased at $30^{\circ}C$ rather than at $20^{\circ}C$. The number of total bacteria increased during 6 days of fermentation and decreased gradually thereafter, and coliform bacteria were not detected after 8 to 10 days of fermentation at 20 and $30^{\circ}C$. Enzyme activities (invertase, amylase, and cellulase) of fermented OJ with $50^{\circ}Brix$ sugar solution were the highest among the different treatments after fermentation for 4 days at $30^{\circ}C$. Total polyphenol content and DPPH radical scavenging ability increased during fermentation. The highest total polyphenol contents and DPPH radical scavenging ability were 7.1 mg TAE/mL and 58.6%, respectively, when fermented at $30^{\circ}C$ with $50^{\circ}Brix$ sugar solution.

• The Korean Journal of Pharmacology
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• v.23 no.2
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• pp.77-85
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• 1987

This study was carried out to determine the role of cholinoceptors in the ventrolateral medulla on central control of blood pressure (BP) and heart rate (HR). In rats anesthetized with urethane and paralyzed, microinjections of the neuroexcitatory amino acid L-glutamate (300 ng/site) were performed to functionally identity the vasopressor area (VLPA) and the vasodepressor area (VLDA) in the ventrolateral medulla oblongata. 1. The bilateral microinjection of carbachol (300 ng/site) into the VLPA produced significantly an increase in BP and HR which was not blocked by bilateral pretreatment of hexamethoium ($4\;{\mu}g/site$). 2. The bilateral microinjection of physostigmine (200 ng/site) and oxotremorine (300 ng/site) into the VLPA produced significantly an increase in BP respectively. 3. The bilateral microinjection of atropine ($4\;{\mu}g/site$) into the VLPA produced significantly a decrease in BP and HR. 4. The bilateral micro injection of acetylcholine (500 ng/site) and dimethylphenylpiperazinium (500 ng/site) into the VLDA produced significantly a decrease in BP and HR respectively. 5. The depressor and bradycardiac responses elicited by the bilateral microinjection of acetylcholine (500 ng/site) into the VLDA were blocked by bilateral pretreatment of hexamethonium ($4\;{\mu}g/site$). The results suggest that the activation of cholinoceptors in VLPA produce hypertensive and tachycardiac responses which may be mediated by muscarinic receptors, and the activation of cholinoceptors in VLDA produce hypotensive and bradycardiac responses which may be mediated by nicotinic receptors.

• Horticultural Science & Technology
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• v.31 no.6
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• pp.807-812
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• 2013

In this study, we aimed to develop a simple analysis method for measuring the carotenoids content of pepper powder. A 96-wells polystyrene microplate and an ELISA reader were used for analysis. Although ELISA reader with 450 nm filter was applicable to measure carotenoid contents, the surface of microplates were degenerated by acetone used for carotenoids extraction. However, ten-folded dilute of the color extract with methanol did not affect the surface of polystyrene microplate and components of the color extract could be successfully measured by a ELISA reader, showing a high corelation with ASTA-20.1 method. In addition, this method uses 10 fold less acetone than ASTA-20.1 method resulting less acetone waste. The microplate method using ELISA reader has potential power for analyzing a large number of samples which may be very useful to the practical breeding program for high-colored peppers.

• Korean journal of food and cookery science
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• v.28 no.3
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• pp.257-263
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• 2012

The purposes of this study were to develop value-added sauce (chili hot sauce) products with Korean advanced chili peppers (Capsicum annuum L.), to determine physicochemical characteristics of hot sauces, and to conduct a sensory evaluation of developed hot sauces. American chili hot sauce products were collected from the American local favorites, and were analyzed based on their compositions. The developed Korean hot sauce contained tomato (29.2%), onion (18.2%), sugar (11.5%), vinegar (10.9%), Korean chili peppers (11.0%), herbs, plum extract, and oligosaccharide, and it showed a higher overall acceptability, compared to that of the hot sauce samples. Its physiochemical analysis showed: salt $5.46{\pm}0.21%$, total acidity $6.04{\pm}0.04%$, pH $3.32{\pm}0.25$, and $^{\circ}brix$ $58.50{\pm}0.10$. This result suggests the possibility for developing a processed chili pepper products.

• Korean journal of food and cookery science
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• v.26 no.6
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• pp.753-760
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• 2010

The purpose of this study was to develop value-added seasoning products with Korean advanced chile peppers (Capsicum annuum L.) and investigate their physicochemical characteristics based on sensory evaluation. Ninety-seven chile pepper-related products were collected from American local favorites and analyzed based on their compositions. Yeongyang's chile pepper powders were prepared to develop Korean chile pepper seasoning products and measured for total microbial content (3.36 log CFU/g), moisture content (12.43%), total carotenoids (223.46 mg/100 g), vitamin C (290.33 mg/100 g), ASTA color value (149.37), and capsaicinoids (4.06 mg/100 g). Korean chile pepper seasoning samples for beef showed higher overall acceptability compared to American local favorite seasonings. Completed Korean chile pepper seasoning products contained red pepper (20%), various herbs (26.1%), salt (11.4%), dried mushroom (8.5%), garlic (8.5%), black pepper, curry, paprika, sweet pumpkin (5.7%), and citron (2.8%). This result might show the possibility of replacing mixed seasoning products from foreign countries (USA and Europe).