• Tunnel and Underground Space
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• v.14 no.1
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• pp.54-68
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• 2004

In this study, scaled model tests were performed on blasting demolition of reinforced concrete structures and the experimental results were analyzed in comparison with the results of numerical analysis. The tests were designed to induce a progressive collapse, and physical properties of the scaled model were determined using scale factors obtained ken dimension analysis. The scaled model structure was made of a mixture of plaster, sand and water at the ratio determined to yield the best scaled-down strength. Lead wire was used as a substitute for reinforcing bars. The scaled length was at the ratio of 1/10. Selecting the material and scaled factors was aimed at obtaining appropriately scaled-down strength. PFC2D (Particle Flow Code 2-Dimension) employing DEM (Distinct Element Method) was used for the numerical analysis. Blasting demolition of scaled 3-D plain concrete laymen structure was filmed and compared to results of numerical simulation. Despite the limits of 2-D simulation the resulting demolition behaviors were similar to each other. Based on the above experimental results in combination with bending test results of RC beam, numerical analysis was carried out to determine the blasting sequence and delay times. Scaled model test of RC structure resulted in remarkably similar collapse with the numerical results up to 900㎳ (mili-second).

• Korean Journal of Environmental Biology
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• v.38 no.1
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• pp.197-205
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• 2020

With the purpose of designing companion planting of groundcover plants for ornamental uses, this study identified the yearly growth characteristics of nine species of different life forms, analyzed the coverage characteristics of individual plants, and suggested combinations of plants suitable for each life form. Polygonatum odoratum var. pluriflorum, Liriope platyphylla and Hosta capitata, as short-grained plants that can grow to more than 20 cm, tended to grow for 60 days after planting in April and maintain their shape thereafter. Their aerial parts started to wither and enter dormancy after September. Saxifraga stolonifera, Dianthus chinensis and Sedum middendorffianum tended to continuously grow until September after planting in April and their growth declined after September. Lysimachia nummularia, as a creeping plant that grows creeping on the ground, started to show a rapid growth three months after planting. Sedum sarmentosum grew slowly until August and the aerial parts started to wither from September when the temperature decreases. The coverage characteristics of these nine species that grow differently after companion planting were surveyed and the growth of Sedum sarmentosum showed the highest number of companions. It was found that Hosta capitata can be companion planted with Sedum middendorffianum, Saxifraga stolonifera, and Lysimachia nummularia. These results indicate that among different shoot growth types species propagated with their stems creeping on the ground or those that can grow vegetatively with non-rhizome parts are more suitable for companion planting with others than those of which rhizomes branch.

• Korean Journal of Medicinal Crop Science
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• v.26 no.5
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• pp.370-381
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• 2018

Background: To enhance the taste and physiological characteristics of Lycii fructus (Gugija) extracts, we investigated the changes in the physiological characteristics of Gugija extracts caused by adding white ginseng (WG) and red ginseng (RG) Methods and Results: Gugija extracts, including 10G10, 10GW-G8 : 2, -G6 : 4, -G4 : 6, -G2 : 8, and -G0 (mixtures made by replacing 0, 20, 40, 60, 80, and 100% of Gugija with WG), as well as 10G10, 10GR-G8 : 2, -G6 : 4, -G4 : 6, -G2 : 8, and -G0 (mixture made by replacing 0, 20, 40, 60, 80, and 100% of Gugija with RG) were extracted with water at 10 times the respective mixture's volume. The antioxidant activities of Gugija extracts were investigated by assessing their 1,1-diphenyl-2-picrydrazyl (DPPH) and 2,2'-azinobis(3ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity, ferric reducing antioxidant potential (FRAP) activity, nitrite scavenging activity, and angiotensin converting enzyme (ACE) inhibitory activity. As the amount of WG added increased, the DPPH, and, ABTS radical scavenging activity, and FRAP activity of the Gugija extract decreased. The half maximal inhibitory concentration ($IC_{50}$) value of 10G10, 10GW-G6 : 4, 10GR-G6 : 4, and 10GR-G0 for DPPH radical scavenging activity were $25.50{\pm}1.04$, $52.06{\pm}1.46$, $16.87{\pm}1.24$, and $9.50{\pm}0.16{\mu}{\ell}/m{\ell}$, respectively. On the other hand, the physiological activity of Gugija extract increased with the addition of increasing amounts of RG. However, ACE inhibitory activity was the highest ($50.25{\pm}2.58%$) in the Gugija 10-fold extract without any added RG. Conclusions: From the above results, we suggest that adding RG to Gugija extracts increase their antioxidant, FRAP, and nitrite scavenging activities.

• Korean Journal of Medicinal Crop Science
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• v.27 no.2
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• pp.126-135
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• 2019

Background: The ginseng ginsenosides, which have various physiological activities, are known to be more abundant in the leaves than in the roots, and the consumers' interest in ginseng sprout as a functional vegetable has been increasing. Methods and Results: The aim of this study was to investigate the effects of growth period on growth properties, active ingredients and rheology of ginseng sprouts cultivated in a non-heated greenhouse equipped with a shade net for 60 days, starting from the end of May to the middle of July. The chlorophyll content of the leaves decreased, but their length and width increased with increasing cultivation days. In particular, growth increased significantly until 40 days, but only slightly after 50 days. The stem length did not increase greatly from the 20 th to the 30 th day of cultivation, but increased significantly from the 30 th to the 40 th day, and then further increased gradually. The weight of the leaves, stems, and roots increased slightly, but not change significantly. After 40 days of cultivation, the total ginsenoside content increased by 1.07 times in the leaves and decreased by 0.80 times in the roots with increasing cultivation days. The leaf contents of ginsenosides $Rg_1$, Re, $Rb_1$, Rc, $F_3$ and $F_4$ increased with increasing cultivation days. The rheological properties of ginseng sprout showed the greatest influence on stem hardening with increasing cultivation days. Conclusions: Therefore, based on the growth characteristics, active ingredients and physical properties, 40 days after sowing was considered to be an appropriate harvesting time for ginseng sprouts.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.67 no.4
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• pp.362-366
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• 2022

This study was conducted to find out the changes in the growth and yield of ginseng and the changes in the soil of direct-seeded ginseng fields after applying different compaction strengths. As a result of surface soil compactions, the topsoil hardness increases as the strength of treatment increases in the first year but topsoil hardness increased only by applying 30 kg weight of compaction in the second year. The germination rate was significantly higher (79.4% and 79.1% at 25 kg and 30 kg, respectively) in 1st year after the application of soil surface compactions. The longest plant was 35.7 cm in 4- years old ginseng in the control and the height was 26.9 cm and 26.5 cm in the soil surface compactions of 25 kg and 30 kg, respectively. In addition, the higher weight of ginseng roots of 31.3 g and 30.3 g were observed after applying 25 kg and 30 kg compaction treatment, and the lowest root weight of 25.6 g was in the control. Therefore, it is shown that after sowing, applying the weight of 25 kg to 30 kg for soil surface compaction is appropriate for better yield in direct seeded cultivation of ginseng at paddy fields.

• Composites Research
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• v.36 no.2
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• pp.132-139
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• 2023

A linerless composite propellant tank was designed and manufactured by using the carbon fiber-reinforced composite materials which have superior strength-to-weight ratio in order to reduce weight of the tank. In this research, we designed a sub-scale composite propellant tank with a diameter of 800 mm to withstand an MEOP of 1.7 MPa. We manufactured the boss of the tank by using the same composite materials to reduce the thermal expansion difference between the boss and the secondary-bonded composite layers of the barrel in the cryogenic environment. We used the collapsible mandrel to manufacture the tank without any liner. The mandrel was made from epoxy-based composite tooling prepregs to reduce weight of the mandrel. We manufactured the test tanks by laying up the carbon fiber fabric prepregs manually on the mandrel and then applying the autoclave cure process. We performed a proof test, a helium tightness test, a repeated pressurization test, and a burst test in room temperature. The test results demonstrate that the proposed design and manufacture process satisfies all strength requirements as well as an anti-leakage requirement.

• Journal of fish pathology
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• v.18 no.3
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• pp.259-268
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• 2005

This study was conducted to know the differences in pathology between artificially induced hemorrhagic anemia (EHA) and hemolytic anemia (ELA) during the anemic and recovery course, using Nile tilapia (Oreochromis niloticus). EHA were induced by repeated bleedings with a volume of about 1% of body weight through caudal vein. ELA were induced by intraperitoneal injections of 1% phenylhydrazine for 2 times. A period of 16 to 49th day was arbitrarily taken as a recovery phase. There were no prominent clinical signs and gross findings except for pale gills during the anemic state of both. Characteristic erythrocytes with a weekly stained cytoplasm started appearing on the 12th day in both and were still noted on the 49 and 20th day respectively in EHA and ELA. EHA and ELA were normocytic hypochromic and macrocytic normochromic in type respectively, although both were normocytic hypochromic during the recovery phase. In liver, fatty degeneration around central vein on the 12-38th day in EHA and hyaline degeneration around central vein on the 12-26th day in ELA were found. In head kidney, increased hemopoiesis was observed on the 12-26th day in EHA and on the 2-12th day in ELA, and macrophages engulfing erythrocytes were observed on the 16-38th day in EHA and on the 2-12th days in ELA. In spleen, activated ellipsoids on the 12-26th day in EHA. and on the 2-20th day in ELA. In ELA, severe accumulation of hemosiderin in both spleen and head kidney were constantly noted from the 2-49th day. On the 49th, Ht was recovered but Hb was still lower than that of control in both anemia.

• Journal of Plant Biotechnology
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• v.49 no.3
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• pp.240-249
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• 2022

Measuring chlorophyll fluorescence (CF) is a useful tool for assessing a plant's ability to tolerate abiotic stresses such as drought, waterlogging and high temperature. Korean ginseng is highly sensitive to water stress in paddy fields. To evaluate the possibility of non-destructively diagnosing waterlogging stress using chlorophyll fluorescence (CF) imaging techniques, we screened 57 ginseng accessions for waterlogging tolerance. To evaluate waterlogging tolerance among the 2-year-old Korean ginseng accessions, we treated ginseng plants with water stress for 25 days. The physiological disorder rate was characterized through visual assessment (an assigned score of 0-5). The physiological disorder rates of Geumjin, Geumsun and GS00-58 were lower than that of other accessions. In contrast, lines GS97-62, GS97-69 and GS98-1-5 were deemed susceptible. Root traits, chlorophyll content and the reduction rates decreased in most ginseng accessions. Further, these metrics were significantly lower in susceptible genotypes compared to resistant ones. All CF parameters showed a positive or negative response to waterlogging stress, and this response continuously increased over the treatment time among the genotypes. The CF parameter Fv/Fm was used to screen the 57 accessions, and the results showed clear differences in Fv/Fm between the susceptible and resistant genotypes. Susceptible genotypes had an especially low Fv/Fm value of less than 0.8, reflecting damage to the reaction center of photosystem II. It is concluded that Fv/Fm can be used as a CF parameter index for screening waterlogging stress tolerance in ginseng genotypes.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.7
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• pp.1017-1025
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• 2016

This study was performed in order to investigate changes in platycosides, as well as antimicrobial activities of bronchus diseases-inducing bacteria (Corynebacterium diphtheriae, Klebsiella pneumoniae, Staphylococcus aureus, and Streptococcus pyogenes) of Platycodon grandiflorum root (PGR) fermented by lactic acid bacteria (Leuconostoc mesenteroides N12-4, Leuc. mesenteroides N58-5, Lactobacillus plantarum N76-10, L. plantarum N56-12, Lactobacillus brevis N70-9, and L. brevis E3-8). Growth of L. plantarum on PGR was most active during lactic acid fermentation using different strains. Total platycoside, platycoside E, platycodin A, polygalacin $D_2$, polygalacin D, and diapioplatyco-side E contents of PGR fermented for 96 h at $37^{\circ}C$ by Leuc. mesenteroides and L. plantarum increased, whereas contents of platycodin D and platycodin $D_3$ were reduced. The antimicrobial activity on PGR fermented by L. plantarum N56-12 exhibited strong microbial proliferation for all four kinds of bronchus disease-inducing bacteria and was higher than that of non-fermented PGR extract. MIC of fermented PGR extract by L. plantarum N56-12 on C. diphtheriae, K. pneumoniae, S. aureus, and S. pyogenes were 45, 10, 50, and 25 mg/mL, respectively. Thus, this result shows that the antimicrobial activities of bronchus disease-inducing bacteria and platycoside content of PGR by L. plantarum N56-12 were higher than that of non-fermented PGR extract.

• Food Science and Preservation
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• v.24 no.5
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• pp.565-575
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• 2017

This study was carried out to investigate shelf-life and quality of fresh-cut Dungkunma (Dioscorea bulbifera) in order to elevate utilization of Dungkunma a fresh food. Before vacuum-packaging (in polyethylene/polypropylene film ($100{\mu}m$, $15{\times}20cm$, $75{\pm}2cmHg$) and storaging at $2^{\circ}C$, Dungkunma was peeled out and cut to dice type ($2.0{\pm}0.5cm^3$), and then washed and blanched using hot water (at $90{\pm}2^{\circ}C$ with 2% NaCl solution for 30 sec). Blanched Dungkunma was pre-dried at room temperature, $40^{\circ}C$ and $50^{\circ}C$ for removing surface water. Each peeled dice Dungkunma was packed 50 g in polyethylene/polypropylene film ($100{\mu}m$, $15{\times}20cm$) with vacuum treatment ($75{\pm}2cmHg$) and stored at $2^{\circ}C$ for 90 days. Hardness and adhesiveness of Dungkunma blanched by 2% NaCl and pre-dried at $50^{\circ}C$ (SB50) were the highest, but changes were the least during storage. Lightness and yellowness of stored Dungkunma in all treatments decreased slightly while redness increased during storage. Changes of color of SB50 was the least. Total concentration of aerobic bacteria in SB50 was $1.88{\pm}0.18log\;CFU/g$ during 90 days and E. coli was detected in all treatments during whole storage periods. Dioscin and allantoin contents of SB50 were virtually unchanged during the storage. Consequently, the results of this study suggest that vacuum packaged Dungkunma after blanching using 2% NaCl solution could be effective to prolong the quality of fresh-cut Dungkunma.