• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.196-196
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• 2017

Oilseed crop Camelina (Camelina sativa L.) is a suitable for biodiesel production that has high adaptability under low-nutrient condition like marginal land and requires low-input cost for cultivation. Enhanced abiotic stress tolerance of Camelina is very important for oil production under the wide range of different climate. CsRCI2s (Rare Cold Inducible 2) are related proteins in various abiotic stresses that predicted to localized at plasma membrane (PM) and endoplasmic reticulum (ER). These proteins are consist of eight-family that can be divided into tail (CsRCI2D/E/F/G) and no-tail (CsRCI2A/B/E/H) type of C-terminal. However, it is still less understood the function of C-terminal tail. In this study, CsRCI2D/H genes were cloned through gateway cloning system that used pCB302-3 as destination vector. And we used agrobacterium-mediated transformation system for generation of overexpression (OX) transformants. Overexpression of target gene was confirmed using RT-PCR and segregation ratio on selection media. We analyzed physiological response in media and soil under abiotic stresses using CsRCI2D and CsRCI2H overexpression plant. To compare abiotic stresses tolerance, wild type and CsRCI2D/H OX line seeds were sown on agar plate treated with various NaCl and mannitol concentration for 7 days. In the test of growth rate under abiotic stress on media, CsRCI2H OX line showed similar to NaCl and mannitol stress. In the other hand, CsRCI2D OX line showed to be improved stress tolerance that especially increased in 200mM NaCl but was similar on mannitol media. In greenhouse, WT and CsRCI2D/H OX lines for physiological analysis and productivity under abiotic stresses were treated 100, 150, 200mM NaCl. Then it was measured various parameters such as leaf width and length, plant height, total seed weight, flower number, seed number. CsRCI2H OX line in greenhouse did not show any changes in physiological parameters but CsRCI2D OX line was improved both physiological response and productivity under NaCl stress. Among physiological parameters of CsRCI2D OX line under NaCl stress, leaf length and width were observed shorter than WT but it were slightly longer than WT in 200mM NaCl stress. Furthermore, total seed weight of CsRCI2D OX line under stress displayed to decrease than WT in normal condition, but it was gradually raised with increasing NaCl stress then more than WT relatively. These results suggested CsRCI2D might be contribute to improve abiotic stress tolerance. However, function of CsRCI2H is need to more detail study. In conclusion, overexpression of CsRCI2s family can generate various environmental stress tolerance plant and may improve crop productivity for bio-energy production.

• Journal of the Korea Convergence Society
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• v.7 no.6
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• pp.229-236
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• 2016

This study attempted to identify multi-dimensional influencing factors of working condition, job stress and supervision affecting care service personnel's job satisfaction by using structural equation model. From the results of this study, first, working condition (B=.247), job stress (B=-.610) and supervision (B=.635) were analyzed to have statistically significant effects upon job satisfaction as a dependent variable. Approximately 34.9% of job satisfaction was found to be explained through variables put into research models. Second, supervision affecting job satisfaction was found to have mediation effects on job stress. It will be necessary to apply the method to effective manpower management plan through supervision in the manager education course to improve job satisfaction for social service delivery manpower as well as care service in the future.

• Korean Journal of Agricultural Science
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• v.46 no.4
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• pp.723-735
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• 2019

The power-train is the most important component of an agricultural tractor. In this study, the strength of the driving gear transmission of an 82 kW-class tractor was analyzed using equivalent torque during plow tillage. The load measurement system consisted of an engine revolution speed sensor, torque-meters, revolution speed sensors for four axles, and pressure sensors for two hydraulic pumps. The load data were measured during plow tillage for four speed stages: F2 (2.78 km/h), F5 (5.35 km/h), F7 (7.98 km/h), and F8 (9.75 km/h). Aspects of the gear-strength such as bending stress, contact stress, and safety factors were analyzed under two torque conditions: the equivalent torque at the highest plow load for the F8 speed stage and the maximum engine torque. The simulation results using KISSsoft showed that the maximum engine torque conditions had a lower safety factor than did the highest equivalent torque condition. The bending safety factors were > 1 at all gear stages, indicating that gear breakage did not occur under actual measured operating conditions, nor under the maximum torque conditions. However, the equivalent torque condition in the contact stress safety factor was > 1, and the maximum torque condition was < 1 at the first gear pair. The method of analysis using the equivalent torque showed lower stress and higher safety factor than did the method using maximum torque. Therefore, when designing a tractor by applying actual working torque, equivalent torque method would support more reliable product development.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.5
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• pp.537-542
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• 2011

The thermo-mechanical interaction between brake block and wheel tread during braking has been found to cause thermal crack on the wheel tread. Due to thermal expansion of the rim material, the thermal cracks will protrude from the wheel tread and be more exposed to wear during the wheel/block contact than the rest of the tread surface. The wheel rim is in residual compression stress when is new. After service running, the region in the tread has reversed to tension. This condition can lead to the formation and growth of thermal cracks in the rim which can ultimately lead to premature failure of wheel. In the present paper, the thermal cracks of railway wheel, one of severe damages on the wheel tread, were evaluated to understand the safety of railway wheel in running condition. The residual stresses for damaged wheel which are applied to tread brake are investigated. Mainly X-ray diffusion method is used. Under the condition of concurrent loading of continuous rolling contact with rails and cyclic frictional heat from brake blocks, the reduction of residual stress is found to correlate well with the thermal crack initiation.

• Korean Journal of Acupuncture
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• v.31 no.4
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• pp.218-224
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• 2014

Objectives : Zizyphus jujuba fruits(ZJF), a traditional Korean medicine has various biological activities such as anti-inflammatory, anti-oxidative and neuro-protective effects. However, it is still unclear whether ZJF has any biological effect on anti-aging. In this study, we examined the effect of ZJF on lifespan and thermal stress in C. elegans. Methods and Results : ZJF water extracts were fermented for 7 days(F7-ZJF) and 14 days(F14-ZJF) by Laetiporus sulphureus to increase secondary metabolites such as aglycone of flavonoids and terpenoids. In the lifespan assay, ZJF water extracts and fermented ZJF were treated on the agar medium plate with age synchronized egg stage of C. elegans. Treatment of F7-ZJF-$200{\mu}g/mL$ with OP-50 E. coli and F14-ZJF-$200{\mu}g/mL$ with OP-50 E. coli significantly increased life span of C. elegans(N2) at thermal stress condition of $25^{\circ}C$. Moreover mRNA levels of lifespan associated HSP 16.1, HSP 70, and HSF-1 were increased at thermal stress condition of $25^{\circ}C$. However, in the equilibration temperature of $20^{\circ}C$ after stress condition of $35^{\circ}C$ for 2 hr, F-14-ZJF-$200{\mu}g/mL$ treatment decreased the levels of heat shock protein in hsp16.2/GFP C. elegans. Conclusions : Our study indicates that prolong role of fermented-ZJF in C. elegans is mediated by control HSPs production.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.15 no.1
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• pp.71-76
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• 2019

Actual stress distributions in the nozzle of a pressure vessel may not be in plane strain condition, implying that the crack-tip constraint condition may be relaxed in the nozzle. In this paper, a methodology for evaluating the fracture toughness of the ASME Code is presented considering the relaxation of the constraint effect in the nozzle of the reactor pressure vessel. The crack-tip constraint effect is quantified by the T-stress. The equation, which represent the relation between the fracture toughness in the lower constraint condition and the plane strain fracture toughness, is derived using the T-stress. This equation is similar to the method for evaluating the fracture toughness of the Master Curve for low constraint conditions. As a result of evaluating the fracture toughness considering the constraint effect in the reactor inlet, outlet and direct injection nozzles using the proposed equation, it was confirmed that the fracture toughness in the nozzles is higher than the plane strain fracture toughness. Applying the proposed evaluation methodology, it is possible to reflect the relaxation of the constraint effect in the nozzles of the reactor pressure vessel, therefore, the safe operation area on the pressure-temperature limit curve can be prevented from being excessively limited.

• Journal of the Korean Home Economics Association
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• v.42 no.10 s.200
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• pp.91-104
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• 2004

The purpose of this study was to examine the differences of clothing microclimates and the subjective sensations according to age, gender and clothing weight for $19^{\circ}C$ air temperature. This study was done to gain fundamental data related to saving heating energy and to improve health through wearing underwear (long johns) in lower indoor temperatures. The subjects were divided into four groups (6 young males, 5 young females, 6 old males, 6 old females), and our experiment consisted of three conditions; the first condition was wearing long underwear in $19^{\circ}C$ air (19CUW condition); the second condition was without wearing long underwear in $19^{\circ}C$ air (19C condition); and the third condition was without wearing underwear in $24^{\circ}C$ air (24C condition). The experiment showed that the clothing microclimate temperature and humidity was the lowest in the 19C condition and the highest in the 24C condition irrespective of age and gender. The clothing microclimate in the 19CUW condition was not significantly distinguishable from the other conditions. Clothing microclimate temperature and humidity when the subjects responded thermal comfort was $28\~34^{\circ}C$ and $15\~40\%$RH without any significant difference according to age and gender. For the thermal sensation, the 24C condition was regarded as the warmest environment by the four groups, and the next preference was the 19CUW condition (p<0.001). Young females and old males showed a tendency to feel colder than young males and old females. For the thermal sensation of hands and feet, the young groups felt the warmest in the 24C condition and the coolest in the 19 C condition (p<0.001). However, old males felt neutral for the foot thermal sensation without any significant difference between the three conditions. Old females felt neutral for both the hands and feet thermal sensations without any significant difference between the three conditions. Thermal preference was the highest in the 24C condition for the 4 groups. In the 19CUW condition, for the thermal preference, most young males and females responded 'No change'; on the other hand, mea of the old responded 'Warmer'(p<0.001). It was the 24C condition that the 4 subject groups felt the most thermally comfortable. In the 19CUW condition, over $80\%$ of responses of each group expressed satisfaction and in the 19C condition, over $80\%$ of responses of each group, except young females, expressed satisfaction. In conclusion, in view of the clothing microclimate and subjective sensations, the 24C condition was the condition that gave subjects the least cold stress and the best subjective preference. However, the 19C condition and the 19CUW condition was not such a cold stress as to give healthy subjects a thermal burden.

• Journal of Industrial Technology
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• v.7
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• pp.49-58
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• 1987

To investigate the effect of the Retrogression and Reaging (RRA) treatment on the strength and the stress corrosion cracking in AA 7039 the measurement of hardness, tensile properties and the time to failure in a constant rate method were measured. Transmission electron microscope was used to examine the microstructural changes within graln and grain boundary. The results show that the RRA treatment of the T6 condition results in a significant increase in the time to failure without sacrifying the original T6 strength. It is believed that high density and even distribution of precipitates in RRA condition were observed within grain so that the RRA condition could have similar strength to the T6 condition. The presence of fine dispersion of semicohernt ${\eta}^{\prime}$ transition phase is also believed to contribute to that effect. Examination of the grain boundary microstructure shows that the RRA treatments increases significantly the average size of the grain boundary preciptates. It is suggested that the benificial effect of the RRA treatment on the susceptibility to SCC be due to the increase in the size of grain boundary precipitates obtained during the retrogression treatment.

• Journal of Industrial Technology
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• v.30 no.B
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• pp.17-23
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• 2010

Since the propagation of a short fatigue crack is directly related to the large crack which causes the fracture of bulk specimen, the detailed study on the propagation of the short crack is essential to prevent the fatigue fracture. However, a number of recent studies have demonstrated that the short crack can grow at a low applied stress level which are predicted from the threshold condition of large crack. In present study, the threshold condition for the propagation of short fatigue crack is examined with respect to the micro-structure and cyclic loading history. Specimens employed in this study were decarburized eutectoid steels which have various decarburized ferrite volume fraction. Rotating bending fatigue test was carried out on these specimens with the special emphasis on the "critical non-propagating crack length" It is found that the reduction of the endurance limit of their particular micro-structures can be due to the increase of the length of critical non-propagating crack, and the quantitative relationship between the threshold stress ${\sigma}_{wo}$ and the critical non-propagating crack length $L_c$ can be written as ${\sigma}_{wo}{^m}{\cdot}L_c=C$ where m,C is constant. Further experiments were carried out on cyclic loading history on the length of critical non-propagating crack. It shown that the length of critical non-propagating crack is closely related to cyclic loading history.

• Journal of Applied Reliability
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• v.17 no.4
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• pp.325-331
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• 2017

Purpose: There is active research that improves both reliability and fatigue life of structures which widely used in the aerospace fields of defense industry. The effects of three parameters (pressure, peening time, nozzle distance) on Almen intensity and coverage will be investigated by using the experimental and analyzed data. Methods: we employed a Box-Behnken design. Additionally, to verify the validity of the optimal condition obtained from experimental results, metallurgical analyses of the shot-peened aerospace part were conducted with respect to surface morphology, residual stress. Results: Optimal shot peening condition is determined as (distance, pressure, time) by optimizing simultaneously the two responses of intensity and coverage. At the optimal peening condition the prediction interval for Almen intensity is well within the required range. And, the validity of the condition was checked by using the real aerospace aluminum alloy plate. Conclusion: Shot peening introduces significant levels of compressive residual stress and induces improves both reliability and fatigue life of structures.