• Journal of Korean Society of Steel Construction
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• v.20 no.6
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• pp.723-730
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• 2008

Due to the higher ratio of live load to total loads of railway bridges, the accumulated damage by cyclic fatigue is significant. Moreover, it is highly possible that the initiated crack grows faster than that of highway bridges. Therefore, it is strongly needed to assess the safety for the accumulated damage analytically. The initiation and growth of fatigue-crack are related with the stress range, number of cycles, and the stiffness of the structural system. The stiffness of the structural system includes uncertainties of the planning, design, construction and maintenance, which varies as time goes. In this study, the authors developed the design and risk assessment techniques based on the reliability theories considering the uncertainties in load and resistance. For the probabilistic risk assessment of crack growth and the remaining life of the structures by the cyclic load of railway and subway bridges, response surface method (RSM) combined with first order second moment method were used. For composing limit state function, the stress range, stress intensity factor and the remaining life were selected as input important random variables to the RSM program. The probabilities of failure and the reliability indices of fatigue life for the considered specimen under cyclic loads were evaluated and discussed.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.8
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• pp.765-770
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• 2017

GTD111 DS of nickel base superalloy has been used for gas turbine blades. In this study, low cycle fatigue test was conducted on the GTD111 DS alloy by setting conditions similar to the real operating environment. The low cycle fatigue tests were conducted at room temperature, $760^{\circ}C$, $870^{\circ}C$, and various strain amplitudes. Test results showed that fatigue life decreased with increasing total strain amplitude. Cyclic hardening response was observed at room temperature and $760^{\circ}C$; however, tests conducted at $870^{\circ}C$ showed cyclic softening response. Stress relaxation was observed at $870^{\circ}C$ because creep effects occurred from holding time. A relationship between fatigue life and total strain range was obtained from the Coffin-Manson method. The fratography using a SEM was carried out at the crack initiation and propagation regions.

• Journal of Bio-Environment Control
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• v.32 no.3
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• pp.210-216
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• 2023

Conventionally, the seeds of Rehmannia glutinosa (Gaertn.) Libosch. ex Steud. have been directly sown at the field without using the plug seedling method. Plug seedlings have the advantage of promoting germination and convenient transplanting. However, there is little information about propagation of R. glutinosa using the plug seedling method. This study was conducted to investigate the optimal seed rhizome length, diameter, and sowing direction of R. glutinosa for establishing the plug seedling method. Seed rhizome length and diameter were separated by 1, 2, 3 cm and 0.3-0.5, 0.6-1.0, 1.1-1.5 cm, respectively. And seed rhizomes were sown in vertical and horizontal directions. The survival rate in 1 cm length of seed rhizomes was lower than in other treatments. The leaf length, leaf width, number of leaves, SPAD, leaf area, and fresh and dry weights of shoot and roots were the greatest in 3 cm length of seed rhizomes. As the seed rhizome diameter decreased, the growth characteristics of R. glutinosa tended to increase. When R. glutinosa was sown horizontal direction, the leaf length, leaf width, number of leaves, and leaf area were significantly higher than in the vertical direction. In conclusion, when sowing seed rhizome in a plug tray, using a length of 3 cm, a diameter of less than 1 cm, and sowing in a horizontal direction is considered an appropriate sowing method for R. glutinosa.

• Journal of the Korean Society of Clothing and Textiles
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• v.30 no.3 s.151
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• pp.458-469
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• 2006

The purpose of this study was to prove that interchange is a primary factor in costume changes through case analysis in costume culture interchange, and further, to assist in gaining understanding of costume changes of the present and the future, and therefore, in this study, cases analysis was conducted focusing on interchange resulting from political factors. In order to present theories that are able to analyse costume culture interchange, culture, cultural exchange, and costume cultures were examined, and based on the results, a costume culture interchange process model and its three steps, propagation, selection, and reinterpretation, were presented. The results of case study on costume culture interchange resulting from political factors based on the costume culture interchange process model presented are as follows. Interchanges that politically uses the possibility of expressing costume as symbols are in most cases aggressive and semi aggressive. In order to exhibit superiority of themselves, the aggressors forced their national costumes onto the receiving culture. Rather than a simple introduction of their costumes, it was an attempt to introduce they values and their ways of life. The conclusion that can be reached through such result is that interchange is an important driving force for changes in costume culture. All interchanges were not greatly affected by methods of propagation and acceptance, and resulted in fusion. Fusion is a process in which existing costume and foreign costume come together constructively to for a new costume culture therefore change in costume style is inevitable.

• Journal of Bio-Environment Control
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• v.16 no.2
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• pp.146-150
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• 2007

For autumn cutting of Sedum sarmentosum, the influences of bedsoil and cutting date were investigated. Among six kinds of bedsoils mixed upland soil, carbonized rice and sand, the mixture with upland soil and sand (1:1 and 2:1, v/v) showed excellent root and shoot growth. The mixtures with upland soil and carbonized rice were lower rooting than the mixture with upland soil and sand. In field condition, autumn cutting was conducted with $10{\times}5cm$ space using the mixture with upland soil and sand (2:1, v/v) at intervals of 10 days from September 1 to October 10. Both root and shoot growth were significantly decreased by delayed date. In cutting from early to middle September, root and shoot growth, and number of rosette before wintering were desirable for shoot production next spring. The safety date to autumn cutting before wintering was on September 20 in field condition. If autumn cutting is late than September 20, the number of scion has increased 25-30% to secure a full rosette before wintering. The results could provide the beneficial information for cutting propagation of S. sarmentosum under field condition in autumn.

• Journal of Bio-Environment Control
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• v.24 no.3
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• pp.167-172
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• 2015

The aim of this study was to develop an effective production system of blueberry plants by using tissue culture technique. Murashige and skoog medium (MS) and woody plant medium (WPM) were compared for shoot formation of highbush blueberries. Also medium supplemented with zeatin/2-isopentenyl adenine (2iP)/benzyl aminopurine (BA) (1, 2/10, 15/4, $6mg{\cdot}L^{-1}$)and zeatin/2iP/BA (0.5/10, 15/$0.05mg{\cdot}L^{-1}$) as plant growth regulators to determine the effect of shoot formation and shoot proliferation, respectively. The shoot explants cultured on WPM showed higher shoot formation rates, more number of nodes, and longer root length than those on MS medium during the primary culture. Shoots were not formed when the explants were cultured on the medium without plant growth regulators or on only BA. The shoot explants cultured on the medium supplemented with 2iP showed low rates of shoot formation. On the other hand, zeatin was the most effective for shoot formation and growth of the explants. Also influence of different cytokinins (zeatin, 2iP) on the shoot proliferation of subcultured shoot explants was studied. There was no significant difference among the different concentrations of zeatin in the rate of shoot formation and number of shoots. However at higher concentration of zeatin, number of nodes was increased, and shoot length was shorted. The proper concentrations of zeatin for shoot propagation in subculture were found to be $0.5mg{\cdot}L^{-1}$ and $1mg{\cdot}L^{-1}$.

• Journal of Navigation and Port Research
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• v.43 no.6
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• pp.475-482
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• 2019

The increase in human use and activity in the oceans is leading to marine pollution and habitat destruction. As a result, in particular, marine animals with a long life cycle and small population are threatened with extinction. Thus, the Korean government designated 11 artificial habitats, such as aquariums and marine museums, as Ex-situ conservation institutions to preserve endangered marine life in 2010. However, studies on the significance and economic value of Ex-situ conservation institutions providing marine life conservation services have not been conducted. Thus, the purpose of this study was to estimate the public's quantitative support for the operation policy of Ex-situ conservation institutions, which is a management method for the protection and propagation of marine animals in Korea. To achieve this, the economic value of the marine animal conservation role of the National Maritime Museum was estimated, operated as an Ex-situ conservation institution for the preservation of green turtles in Korea. By using the representative non-market valuation method for public goods known as the contingent valuation method (CVM), the economic value of the Ex-situ conservation institution (National Maritime Museum) was estimated at approximately 41.8 billion won to a maximum of 78.1 billion won. The results of this study can be applied as basic data for marine animal management policymakers in establishing efficient management plans for endangered marine animals in Korea's coastal waters.

• Korean Journal of Medicinal Crop Science
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• v.5 no.1
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• pp.49-55
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• 1997

This study was conducted to establish mass propagation system from the tissue culture using immature embryos in Eleutherococcus senticosus. Immature embryos from seeds were removed under the microscope and placed on MS, $MSB_5\;and\;B_5$ medium containing several plant growth regulators. While the calli were well formed on media containing 2 mg/l of 2, 4-D, 2 mg/l of 2, 4-D and 0.7 mg/l of TDZ, shoot regeneration was better on MS medium with combinations of high concentrations of TDZ and low concentrations of 2, 4-D. Treatment of 2, 4-D alone was better than treatment of TDZ alone in callus induction, but plant regeneration was reversed. The results of callus formation and shoot regeneration on $MSB_5\;and\;B_5$ media were similar to those of MS media. The rate of callus formation was nearly 100% when 2, 4-D was added to $B_5$, medium on concentration of 2 mg/l or 0.7 mg/l. TDZ showed very significant effect on the formation of multiple shoots.

• Journal of Bio-Environment Control
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• v.12 no.3
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• pp.132-138
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• 2003

This experiment was conducted to investigate the mass propagation system of Aster glehni FR. and to obtain the basic data for improvement of germination and seedling. The following was the results of experimentation about temperature and light conditions, and priming treatment as kinds of chemicals, their concentration and treated periods affect germination of Aster glehni FR. The germination percentage of Aster glehni FR. seed was higher in 20 and 25$^{\circ}C$ than the others, but it dropped rapidly at 30$^{\circ}C$ and didn't germinate at 35$^{\circ}C$. The first day to germination was the slowest at 15$^{\circ}C$. The germination rate of Aster glehni FR seed increased with increasing with temperatures from 15 to 25$^{\circ}C$. But the seed was rotten easily in high temperature. The germination rate was shown highest in 25$^{\circ}C$, and next was 15, 20, 30$^{\circ}C$ in order. Light treatment enhanced germination percentage, the first day to germination, germination rate and T50, but there was no significant difference. The 3 hours priming treatments had more effect on germination percentage than 30 minutes treatments as comparing averages. Aster glehni FR seeds primed in $KNO_3+K_3PO_4$ for 3 hours had most eHective on germination percentage (83.3%) and also showed shortest $T_{50{\cdot}}T_{50}$ and day of first germination was better in 30 minutes than 3 hours treatments, and most of priming treatments were better than control(non-priming seeds). While priming seeds showed shorter day of first gemination than control, there was no significant difference between 30 minutes and 3 hours treatments.

• Journal of Bio-Environment Control
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• v.29 no.3
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• pp.219-230
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• 2020

This study was conducted to determine the optimum medium and humidification period for the strawberry (Fragaria × ananassa Duch. cv. Maehyang) cutting seedling production. The cuttings were planted in coir (CO), rockwool (RW), phenolic foam (PF), and organic foam medium (OFM) with fogging treatment in 0, 3, 6, 9, or 12 days on February, 2019. And, as the field verification examination research, cuttings were planted in CO, RW, PF, and OFM, with misting treatment in 0, 6, 9, 12, or 15 days on June, 2019. In fogging treatments, rooting and survival rates of seedlings tended to increase with longer fogging periods, and rooting and survival rates were showed significantly higher in CO medium with more than 9 days of fogging periods. In misting treatments, rooting rate was significantly higher in CO and RW medium with more than 9 days of misting periods, and survival rate was significantly higher with more than 12 days of misting periods. There was no significantly difference by growth medium and humidification period in shoot and root growth. Therefore, when considering the rooting and survival rate the CO medium with 9 days of humidification period could be beneficial for the production of the 'Maehyang' strawberry cutting seedlings.