• 한국기계연구소 소보
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• s.18
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• pp.169-175
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• 1988

The influence of mean strain on the behavior of early stage stress amplitude was investigated quantitatively in low cycle fatigue. It was obtained that the exponent of cyclic strain(n') and the coefficient of cyclic strain(C') decreased with increasing cycle numbers in compressive mean strain level. But it was the opposite in 0% mean strain and tensile mean strain level. And the cyclic yield strength ($\delta_(yc)$) was constant irrespective of mean strain or cyclic strain

• Transactions of Materials Processing
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• v.20 no.5
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• pp.344-349
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• 2011

Variation of contact pressure causes change of friction coefficient, which in turn changes stress distribution in the sheet being formed and final springback. In the present study, U-draw bending experiments were carried out under constant blank holding force(BHF) and different blank sizes, and finite element analysis was conducted with and without considering contact pressure effect on friction. When the BHF was sufficiently high, the degree of springback was different between constant blank holding pressure condition and that with varying blank holding pressure. Finite element analysis considering the influence of contact pressure effect on friction could explain the occurrence of springback.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.11
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• pp.348-360
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• 2019

This study examined the influence of humanistic knowledge and occupational stress on the professional quality of life of clinical nurses. The data from 217 survey questionnaires collected from three general hospitals located in a metropolitan area from Jun 3 to 14, 2019 were used. The data were analyzed using a t-test, ANOVA, Scheffè test, Pearson's Correlation Coefficient, and Stepwise multiple regression with SPSS Statistics 23.0 program. The findings revealed a positive correlation between compassion satisfaction and humanistic knowledge and a negative correlation with Burnout. Burnout had a negative correlation with humanistic knowledge and a positive correlation with occupational stress and secondary traumatic stress. Secondary traumatic stress showed a positive correlation with occupational stress. Burnout, satisfaction for nursing, and working period were significant variables of the compassion satisfaction with an explanatory power of 48.5%. Compassion satisfaction, secondary traumatic stress, satisfaction for nursing, marriage, and occupational stress were significant variables of burnout with an explanatory power of 68.8%. Burnout and income were significant variables of secondary traumatic stress with an explanatory power of 21.9%. Burnout was found to be a significant variable of not only compassion satisfaction, but also compassion satisfaction. Therefore, efforts are needed to make efforts to prevent burnout.

• Journal of the Korea Society of Computer and Information
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• v.28 no.10
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• pp.187-195
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• 2023

In this paper aims to identify the effects of professional identity, role conflict and job stress on job satisfaction of nurses in general hospital wards. The subjects of this study were 193 nurses who worked in general hospitals in K district. Data were analyzed using frequency, percentage, mean, standard deviation, t-test, one-way ANOVA, Scheffe test, Pearson's correlation coefficient, and multiple stepwise regression. The results of the study are as follows. First, among the general characteristics, working years in general hospital wards showed a statistically significant difference in professional identity the less the working years in general hospital, the higher the professional identity. Second, professional identity showed a positive correlation with job satisfaction and role conflict, and a negative correlation with job stress. The higher the professional identity, the higher the job satisfaction and role conflict, but the lower the job stress. Role conflict showed a positive correlation with job stress the higher the role conflict, the higher the job stress. Job stress and job satisfaction showed a negative correlation the higher the job stress, the lower the job satisfaction. Third, the factors that affected the job satisfaction of nurses working in general hospital wards were job stress and professional identity, which had an influence of 38%. Thus, to improve the job satisfaction of nurses, it is necessary to develop programs that develop a positive professional identity. In addition, it is necessary to recognize the necessity of relieving job stress caused at work and to secure diverse human and material support resources.

• Geomechanics and Engineering
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• v.21 no.3
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• pp.301-313
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• 2020

In the process of mining closely spaced coal seams, the problem of roadway arrangement in lower coal seams has long been a concern. By means of mechanical model calculation and numerical simulation postprocessing, the distribution of the stress deviator below the floor of a goaf and the evolution of the stress deviator in the vertical and horizontal directions are studied under the influence of horizontal stress. The results of this theoretical study and numerical simulation show that the stress deviator decreases exponentially with increasing depth from the floor below the coal side. With the increase in the horizontal stress coefficient λ, the stress deviator concentration area shifts. The stress deviator is concentrated within 10 m below the goaf and 15 m laterally from the coal side; thus, the magnitude of the surrounding rock stress deviator should be considered when planning the construction of a roadway in this area.

• Journal of Digital Convergence
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• v.18 no.10
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• pp.361-370
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• 2020

This study identified the effect of menstrual attitude, life stress and clinical practice stress on premenstrual syndrome of nursing students. Data were analyzed with the SPSS 22.0 program using descriptive statistics, t-test, ANOVA, Pearson's correlation coefficient and simple linear regression. Premenstrual syndrome was significantly negative correlated with menstrual attitude (r=.28, p=.004), positive correlated with life stress (r=.31, p=.001) and clinical practice stress (r=.29, p=.003). The factors that influence premenstrual syndrome were regular exercise (β=.-.18, p=.006) and dysmenorrhea (β=.51, p=.000), which explained 38.0%.

• Journal of Industrial Technology
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• v.21 no.B
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• pp.295-300
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• 2001

Significant improvements in bond strength between new and existing concrete can be achieved through the modification of the new concrete by latex modification. But, no test method has been adopted as a standard to measure the bond strength between the concrete used to repair and the substrate being repaired. The performance of old and the new concrete construction defends upon band strength between old and the new concrete. Current adhesion strength measurement method is inaccurate method that ignore effect of stress concentration by shape of specimens. Therefore, this research calculates stress concentration coefficient using finite element analysis and direction tensile strength test (pull-off test). The result shows that the required core depth is 2.5 cm. Elastic modulus and overlay thickness do not influence in stress concentration.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.349-354
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• 2002

Significant improvements in bond strength between new and existing concrete can be achieved through the modification of the new concrete by latex modification. But, no test method has been adopted as a standard to measure the bond strength between the concrete used to repair and the substrate being repaired. The performance of old and the new concrete construction depends upon bond strength between old and the new concrete. Current adhesion strength measurement method ignores the effect of stress concentration by shape of specimens. Therefore, this research calculates stress concentration coefficient using finite element analysis and direction tensile strength test (pull-off test). The result shows that the required core depth is 2.5cm. Elastic modulus and overlay thickness do not influence in stress concentration.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.473-476
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• 2003

This paper shows necessity of encapsulation layer to maximite flexibility of brittle indium-tin-oxide (ITO) on polymer substrates. And, Young's modulus (E) of encapsulation layer have an significant effect on external bending stress and the coefficient of thermal expansion (CTE) of that have a significant effect on internal thermal stress. To compare magnitude of total mechanical stress including both bending stress and thermal stress, the mechanical stress of triple-layer structure (substrate / ITO / encapsulation layer or substrate / buffer layer / ITO) can be quantified and numerically analyzed through the farthest cracked island position. As a result, it should be noted that multi-layer structures with more elastic encapsulation material have small mechanical stress compared to that of buffer and encapsulation structure of large Young's modulus material when they were externally bent.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2003.11a
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• pp.118-126
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• 2003

In the present study, the residual stresses can have a significant on the life of structural engineering components. Residual stresses are created by the surface treatment such as shot peening or deep rolling. The objective of this experimental investigation is to study the influence of friction and wear characteristics due to residual stress under dry sliding condition. Friction and wear data were obtained with a specially designed tribometer. Test specimens were made of SUP9(leaf spring material) after they were created residual stress by shot peening treatment. Residual stress profiles were measured at surface by means of the X-ray diffraction. Sliding tests were carried out different contact pressure and same sliding velocity 0.035m/s(50rpm). Leaf spring assembly test used to strain gauge sticked on leaf spring specimen in order to measure interleaf friction of leaf spring. Therefore, we were obtained hysteresis curve. As the residual stresses of surfaces increased, coefficient of friction and wear volume are decreased, but the residual stresses of surfaces are high, and consequently wear volume do not decreased. Coefficient of friction obtained from leaf spring assembly test is lower than that obtained from sliding test. From the results, structural engineering components reduce coefficient of friction and resistant wear in order to have residual stresses themselves.