• Journal of the Korean Wood Science and Technology
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• v.50 no.6
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• pp.427-435
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• 2022

For effective applicability of reinforced cork, cork composites reinforced with metal, glass fiber, and carbon fiber were developed, and the effects of the reinforcing materials on the mechanical properties of cork composites were investigated. The bending moduli of elasticity (MOE) of cork composites were in the 32.7-35.9 MPa range, while the bending strength values were in the 1.62-1.73 MPa range. The strength performance decreased in the order cork-metal > cork-carbon fiber > cork-glass fiber. The bending MOEs were improved by 29%-41% compared with simple cork boards, while the bending strengths of reinforced cork were 35%-45% higher. The strength performance significantly improved following the incorporation of thin mesh materials into the middle layer of the studied cork composites. The bending strains of the cork composites were remarkably higher compared with oak wood, making them promising for applications that require bending processing, such as curved jointing. The internal bond strengths of the cork composites were 0.26-0.44 MPa, approximately 0.36-0.60 times lower compared with medium-density fiber boards.

• Korean Journal of Pharmacognosy
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• v.42 no.2
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• pp.169-174
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• 2011

In this study, we investigated on antioxidative activity, antibacterial activity and tyrosinase inhibitory activity in 75% ethanol extracts of bark and cork layer from Prunus sargentii. The total polyphenol content of cork and bark extract was found to be 217.4 mg/g and 184.3 mg/g. And flavonoid content was found to be 31.9 mg/g and 58.6 mg/g respectively. In DPPH radical scavenging ability, cork extract was exhibited stronger scavenging ability than bark extract. Moreover, cork extract was showed higher inhibitory activity than bark extract in tyrosinase inhibitory activity. In antibacterial activity, bark extract was showed higher growth inhibition effect than cork extract against tested bacterial strains. In measurement of cytotoxicity by MTT assay, bark and cork extract showed fine cell viabilities(95.7~120.9%) against RAW 264.7 cell.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.3
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• pp.362-369
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• 1996

Seven different drying methods were tested in peony roots of Euisung cultivar, harvested in February, in three year's old plant. The roots were selected in length and diameter and half of the samples were removed cork-layers to compare the effects of cork-layer in processing of drying. The 3$0^{\circ}C$ heat drying without cork-layer reduced in days to drying by five days compared to those of the with cork-layers at the same temperature. The 5$0^{\circ}C$ heat drying after cork-layers removed was the most effective in days to drying. In quality of skin color of the 5$0^{\circ}C$ heating was worse to compare with the lower drying temperature. In the drying at room temperature and the heat drying at lower temperature, the paeoniflorin content in drying after cork-layers removed were higher than that of the drying with cork-layers. However, in the boiling water treatment, the paeoniflorin contents in drying after cork-layers removed were lower than those of with cork-layers. In heat drying, paeoniflorin content showed a decreasing tendency to increase of drying temperature. Total sugars in the peony roots showed a decreasing tendency according to the drying temperature increasing, but starch concentration showed a increasing tendency at the same condition. Concentrations of crude protein, crude fiber and crude ash were showed no differences in various drying methods and the materials with or without cork-layers. Relationships between the paeoniflorin and total sugars, and the paeoniflorin and starch were different significantly by the materials of cork-layers removed or not. The 30~4$0^{\circ}C$ heat drying without cork-layers was the most advisable condition for drying in paeoniflorin concentration, days to drying and skin color after drying.

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.4
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• pp.464-470
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• 2018

A development of one-dimensional thermal analysis tool is performed to estimate the thickness of cork insulation for flight vehicle. In the calculation of cork temperature, the cork density model, heat of ablation and pyrolysis gas enthalpy model were applied. The calculation for the two-layer model of cork and metal was performed by the tool and compared with the experimental data. The results for the two aerodynamic heating conditions were 17 % and -12 % different from the experimental data, respectively. The effect of mechanical ablation not included in the calculation can be expected as the cause of the difference. The temperature-density curve of cork which adjusted by experimental data was also presented.

• Korean Journal of Medicinal Crop Science
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• v.10 no.5
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• pp.392-398
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• 2002

Comparative analysis of paeoniflorin, albiflorin and phenolic compound contents as bioactive components of peony was performed by Reverse Phase-High Performance Liquid Chromatography (RPHPLC) using the four- year-old peony which were different plant parts and pretreatment, such as removing or unremoving the cork layer of peony root before drying. The contents of paeoniflorin, albiflorin, (+)-taxifolin $3-O-{\beta}-D-glucopyranoside$, (+)-catechin and (-)-epicatechin were the highest in rhizome part, but those of gallic acid and benzoic acid in the leaves were higher than other parts. The contents of albiflorin, gallic acid, benzoic acid and (-)-epicatechin in the cork layer were higher than in those of the core, but the contents of paeoniflorin, (+)-taxifolin $3-O-{\beta}-D-glucopyranoside$ and (+)-catechin in the core were higher than those in the cork layer. In general, the rhizome part of peony root has been used only propagation purpose, but this part contained high contents of bioactive component. Therefore, it is needed that medicinal application of rhizome part in peony root was firmly investigated. Also, In the use of peony root for medicinal purpose, the use of peony root with cork layer can be efficient way on the practical use of useful components and the reduction of labor for removing the cork layer.

• Korean Journal of Medicinal Crop Science
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• v.11 no.3
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• pp.201-206
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• 2003

This experiment was conducted to establish the standard of quality evaluation in peony root (Paeonia lactiflora Pall.) cultivated in Korea. The contents of extract and changes of extract pH in peony root with different root ages, cultivars and drying method were investigated. The contents of extract and changes of extract pH in peony root with the removed and the unremoved cork layer showed no difference among different root ages. On the other hand, the contents of extract in the root with the unremoved cork layer which was two- to four-year-old, were higher by 3.7 to 9.2% than those in the root with removed cork layer. This suggests that cork layer might be a good source of extracts. The contents of extract in root of Youngchonjakyak in both the removed and the unremoved cork layer were 36% and 30%, respectively and were higher than of Euisungjakyak and Jomjakyak, but the extract pH was not significantly different among three cultivars which were four-year-old. It showed that the contents of extract and the changes of extract pH in peony root with the removed and the unremoved cork layer of Euisungjakyak, which being four-year-old, showed clear difference at various drying methods. Among the different drying methods, it showed that the contents of extract of that with unremoved cork layer in the room temperature drying method was 32.8%, and that of root with the removed cork layer in the $80^{\circ}C$ hot water treatment drying method was 28.1% which were the highest values, respectively. The pH of extract in freeze drying was the highest (about 5.1), and the $80^{\circ}C$ hot water treatment drying showed the lowest (about 3.7).

• The Korean Journal of Ecology
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• v.14 no.2
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• pp.159-169
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• 1991

Floristic cmposition and soil properties were analyzed in chines cork oak(quercus variabilis)cmmunities in the limestone area, tanyang, ch'ungbuk province in korea. The tree layer was composed of quercus dentata, platycarya strobilacea, fraxinus rhynchophylla and others as wel as quercus variabilis. the shrub layer was dominated by ulmus davidiana for. suberosa,shrubby q. variabilis. euonymus alatus and rhus chinensis. among these, u. davidiana for. suberosa was known to have a restricted distribution to calcareous area, and 9 species in the shrub layer including e. alatus, indigofera kirilowii and rhamnus davurica belonged to the calcicole. The herb layer was dominated by carex lanceolata and spodiopogen cotulifer. ten specirs including g. lanceolata, clematis mandshurica, isachne globosa, lithospermum arvense and scabiosa mansenensis belonged to the calcicode. soil texture was classified to clay loam in both top and subsoil. Water cotent and organic matter were consistentl higher in top soil than in subsoil. soil ph rangd 7.8~8.4. Total n concentration in top soil ranged from 0.2 to 0.4mg/g, which was higher than that in subsoil. Available p and exchangeable k concentretion were also significantly higher in op soil than in subsoil. However, exchangeable ca concentration was similar betweenthe top and the subsoil. Unlike the other nutrients, exchangeable mg concentration in top soil was lower than that in subsoil. orangic matter, n, p and k content in this chinese cork oak stand showed as much as the other noncalcareous sites. Soil properties in this study area seemed to have been influenced by casts forming activities of earthworms.

• Korean Journal of Pharmacognosy
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• v.42 no.3
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• pp.213-217
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• 2011

Platycodon grandiflorum (Campanulaceae) is listed in Shin-Nong-Bon-Cho-Kyung (神農本草經) as the remedy for ventilation the lung, resolving phlegm, promoting pus discharge and subduing carbuncles. The prescriptions of Gil-Gyung-Tang (桔梗湯) are also recorded in many other Chinese medicinal books. The identification of the cultivation year of P. grandiflorum is very important in commercial market as well as in research field. However, any reports about it have not been clearly established yet. To clarify the criterion, the morphological and anatomical characteristics of the roots of P. grandiflorum cultivated in Korea for various years were studied. The characteristics of the cork layer, latex tube, and vessels were shown to be useful keys to confirm the cultivation year of P. grandiflorm. As a result, it was clarified that Kilkyung from Korea was the two years root of Platycodon grandiflorm.

• Korean Journal of Pharmacognosy
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• v.35 no.1 s.136
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• pp.45-51
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• 2004

Panax ginseng C. A. Meyer (Araliaceae) is listed in Shen Nung Pentsao Ching(神農本草經) as the remedy for replenishing the primodial qi(氣), restoring pulse, treating collapse, tonifing the spleen and lag, promoting the production of body fluid to quench thirst, tranquilizing the mind, and improving the function of brain. The prescriptions of In Sam Tang(人參揚) are also recorded in many other Chinese medical books. The identification of the age of Panax ginseng is very important in commercial market as well as in research field. However, any reports about it have not been clearly established yet. To clarify the criterion, the morphological and anatomical characteristics of the roots of various age Panax ginseng cultivated in Korea were studied. The characteristics of cork layer, secretory canal, and vessel were shown to bε useful keys to confirm the age of Panax ginseng.

• Korean Journal of Medicinal Crop Science
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• v.20 no.3
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• pp.159-164
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• 2012

In this study, we investigated the antibacterial activity, antioxidative activity and whitening effect of 75% ethanol extracts from different parts of Prunus sargentii. The total phenolic compound content of the branch extract was 277.92 mg/g as the highest level. In the measurement of DPPH radical scavenging ability, $SC_{50}$ values of the cork layer and branch extract were 26.79 ${\mu}g/m{\ell}$ and 30.13 ${\mu}g/m{\ell}$. In nitric oxide (NO) scavenging ability, $SC_{50}$ values of the branch and leaf extract were 49.19 ${\mu}g/m{\ell}$ and 55.55 ${\mu}g/m{\ell}$. All extracts exhibited higher NO scavenging ability than ascorbic acid used as positive control. On the other hand, in antibacterial activity against Staphylococcus epidermidis and Staphylococcus aureus by disc diffusion assay, the pure bark extract showed the highest activity. Moreover, tyrosinase inhibitory activity of cork layer, pure bark and branch extracts showed higher activity than arbutin used as positive control. In the cytotoxicity measurement by MTT assay, leaf extract was exhibited Raw 264.7 cell viabilities of 44.68~61.83% as cytotoxic result in tested concentration. In conclusion, the branch extract of Prunus sargentii will be a functional materials without damage compared to other parts such as pure bark or cork layer in the plant.