• 한국공작기계학회논문집
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• 제14권5호
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• pp.62-73
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• 2005

The objects of this research are to establish the criteria of peel occurrence considering the shape of bond terminus and to compare the strength properties of adhesive joint of different three type such as butt joint, T-shape, and single lap Joints. The criteria of peel occurrence at the bond terminus was suggested. Peel loads of three type adhesive joint (butt Joint, T-shape specimen, single lap joint) were determined from tensile tests. Principal stress distributions of these joints were determined from finite element method analysis. Then, peel occurrence was estimated with stress singularity factor$(K_{prin})$ when the terminus shape was square, with average principal stress when the terminus shape was rounded. The conclusions are summarized as follows; (1) In the non-filleted model(e.g., butt joint, T-shape specimen), principal stress shows singularity at the bond terminus, intensity of stress(principal stress) singularity $(K_{prin})$ can use as the criteria of peel occurrence at the bond terminus. (2) In the filleted model(e.g., single lap joint), principal stress has not affected singularity at the bond terminus. Average principal stress$(K_{av})$ can use as the criteria of peel occurrence at the bond terminus.

• 한국해양공학회지
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• 제28권1호
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• pp.34-46
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• 2014

This paper discusses a new formulation for the failure strain in the average stress triaxiaility domain for a low-temperature high-strength steel (EH36). The new formula available at a low average stress triaxiality zone is proposed based on the comparison of two results from tensile tests of flat type specimens and their numerical simulations. In order to confirm the validity of the failure strain formulation, a user-subroutine was developed using Abaqus/Explicit, which is known to be one of the most popular commercial finite element analysis codes. Numerical fracture simulations with the user-subroutine were conducted for all the tensile tests. A comparison of the engineering stress-strain curves and engineering failure strain obtained from the numerical simulation with the user-subroutine for the tensile tests revealed that the newly developed user-subroutine effectively predicts the initiation of failure.

• Journal of Biosystems Engineering
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• 제9권2호
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• pp.27-36
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• 1984

This study was carried out to investigate the effects of the tilling depth, tilling travel speed and soil shear stress on the tilling load characteristics and power requirement for rotary tillers. The results obtained from the study are summarized as follows. 1. The average and maximum PTO torque increased as the tilling depth, tilling pitch and soil shear stress increased. A multiple linear regression equation to estimate the average PTO torque in terms of the above parameters was developed. 2. The ratios of maximum PTO torque to the average torque were in the range of 1.17 to 1.65 for the various tilling conditions tested. The variation in PTO torque increased greatly as the tilling pitch and soil shear stress increased, but decreased as the tilling depth increased. 3. Power requirement for the PTO shaft increased with the tilling depth, travel speed and soil shear stress, but decreased slightly as the tilling pitch increased. A multiple linear regression equation to estimate power requirement for the PTO shaft in terms of the above parameters was developed. 4. The specific power requirement for the rotary tiller was in the range of $0.008-0.015ps/cm^2$ for the various tilling conditons tested. The specific tilling capacity decreased as the tilling depth and soil shear stress increased, but increased with the tilling pitch. A multiple linear regression equation to estimate the specific tilling capacity in terms of the above parameters was developed.

• 가정과삶의질연구
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• 제34권6호
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• pp.41-54
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• 2016

The purpose of this study was to examine the effects of husband's emotional support and mother-teacher partnership on maternal parenting stress. The participants in this study consisted of 216 mothers with children(aged 4-5years). Husband's emotional support was measured by the Parenting Alliance Inventory(PAI, R. R. Abidin, 1988) revised by R. R. Abidin and J. F. Brunner(1995). Mother-teacher partnership was measured using the Caregiver-Parent Partnership Scale(A. M. Ware, B. Barfoot, A. S. Rusher & M. T. Owen, 1995) revised by M. T. Owen, A. M. Ware and B. Barfoot(2000). Parental Stress was measured by the Parenting Stress Index-Short Form(PSI-SF, R. R. Abidin, 1995) revised by M. E. Haskett, L. S. Ahern, C. S. Ward and J. C. Allaire(2006). The data were analyzed through mean, standard deviation, t-test, ANOVA, Pearson's correlation, and hierarchical multiple regression. The results of this study were as follows: First, the mean score of husband's emotional support was higher than average and the mean score of mother-teacher partnership was an average level. Parenting stress was lower than average. Second, there were statistically differences in maternal parental stress according to number of children and mother's educational level. Third, husband's emotional support and mother-teacher partnership were influenced by maternal parental stress. The results of this study are important because they show mothers, fathers, and teachers ways to reduce maternal parental stress.

• 여성건강간호학회지
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• 제21권2호
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• pp.83-92
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• 2015

Purpose: The purpose of this descriptive study was to assess levels of stress, coping style, and nursing needs for hospitalized pregnant women diagnosed with preterm labor. Methods: Data were collected from 125 pregnant women aged between 20 and 40 years and diagnosed with preterm labor by OBGY units at 3 hospitals. Data were analyzed by frequency, percentage, t-test, and ANOVA with $Scheff{\acute{e}}$ test. Results: The level of stress among women was an average of 2.13 out of 4 points, the level of coping style was an average of 2.66, and nursing needs was an average of 2.83 out of 4 points. The level of stress was significantly different by job, length of hospital stay, type of hospital, and history of admission at obstetric unit. The level of coping style was significantly different by age and monthly income. The level of nursing needs was significantly different by type of hospital. Higher level of stress and coping style were related to higher level of nursing needs. There was no significant correlation between stress and coping style. Conclusion: The result showed the importance of nursing intervention dealing with stress, coping style and nursing needs for women with preterm labor. Nurses need to provide nursing interventions to reduce the stress, to strengthen the coping style, and to satisfy the nursing needs for pregnant women hospitalized due to preterm labor.

• 대한치과의료관리학회지
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• 제11권1호
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• pp.28-37
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• 2023

In this study, in order to analyze the effects of dental technology students' degree of satisfaction with their major and sense of self-esteem on college life stress, we conducted a self-administered questionnaire for 270 dental technology students. conducted a frequency analysis, t-test, one-way ANOVA, correlation analysis, and multiple regression analysis, and the results are as follows. As a result of analyzing the degree of major satisfaction, there was a significant difference in the department satisfaction (p<.05). The average score in major satisfaction was relatively high at 3.68. As a result of analyzing the level of self-esteem, there was a significant difference in grade and department satisfaction (p<.05). The average score in self-esteem question was relatively high at 3.75. As a result of analyzing the level of college life stress, there was a significant difference in the department satisfaction (p<.05). The average score for each college life stress area was relatively low at 1.97. As a result of analyzing the correlation between college life stress, major satisfaction, and self-esteem, college life stress was found to have a significant negative (-) correlation with major satisfaction and self-esteem. As a result of a regression analysis conducted on the effect of self-esteem and major satisfaction on college life stress, the variable that most influenced college life stress was found to be the self-esteem factor.

• 한국지반공학회논문집
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• 제33권1호
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• pp.79-91
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• 2017

반복단순전단시험기를 이용하여 해양실트질 모래의 상대밀도 변화에 따른 비배수전단파괴 거동에 대해 평균전단응력과 반복전단응력이 미치는 영향을 평가하였다. 시험결과 반복전단 변형모드는 상대밀도가 달라지더라도 유사한 양상을 보였으며, 평균전단응력과 반복전단응력으로부터 큰 영향을 받았다. 파괴에 필요한 반복하중 횟수는 반복전단응력비, 상대밀도, 그리고 평균전단응력비의 순서로 좌우되는 것으로 나타났다. 본 논문에서는 조밀한 지반과 느슨한 지반에서 상대밀도 변화에 따른 응력기반 파괴경로의 변화를 2차원과 3차원으로 제시하였으며, 3차원 파괴선도는 조밀한 지반 조건에 대해서만 한정된 한계점을 보완하여 지반의 상대밀도에 따라 반복전단응력비, 평균전단응력비, 반복하중 횟수 등의 설계 조건을 결정 할 수 있는 아주 유용한 설계도구로 활용 가능하다.

• 한국해양공학회지
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• 제31권4호
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• pp.288-298
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• 2017

A study of the damage evolution laws for ductile materials was carried out to predict the ductile fracture behavior of a marine structural steel (EH36). We conducted proportional and non-proportional stress tests in the experiments. The existing 3-D fracture strain surface was newly calibrated using two fracture parameters: the average stress triaxiality and average normalized load angle taken from the proportional tests. Linear and non-linear damage evolution models were taken into account in this study. A damage exponent of 3.0 for the non-linear damage model was determined based on a simple optimization technique, for which proportional and non-proportional stress tests were simultaneously used. We verified the validity of the three fracture models: the newly calibrated fracture strain model, linear damage evolution model, and non-linear damage evolution model for the tensile tests of the asymmetric notch specimens. Because the stress evolution pattern for the verification tests remained at mode I in terms of the linear elastic fracture mechanics, the three models did not show significant differences in their fracture initiation predictions.

• 한국생활과학회지
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• 제17권1호
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• pp.27-34
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• 2008

The purpose of this study is to study how college students cope with their stress and how the level of their self-differentiation affects degrees of stress and stress-coping strategies. The questionnaires were handed to 497 college students at Y university in Gyeongbuk Province and the data were analyzed in terms of Cronbach's ${\alpha}$-coefficient, frequency and percentage, t-test, and regression analysis by using the SPSS statistical package. The results of this study were as follows: 1. For stress level, degree of self-differentiation and stress coping strategies of the college students, the average scores were 3.56, 2.53 and 3.49, respectively in 5-point Likert Scale, indicating that the students possess the above-average score for the degree of self-differentiation and stress-coping strategies and the below-average score for stress levels. 2. From examination of difference verification of stress levels based on the degree of self-differentiation and effect of degree of self-differentiation on stress levels, it was found that the higher is the degree of self-differentiation the lower is the stress level. 3. From examination of difference verification of stress-coping strategies according to the degree of self-differentiation and effect of degree of self-differentiation levels on stress coping strategies, we found that the students of higher degree of self-differentiation exercise the more active stress coping strategies. These results show that the degree of students' self-differentiation is a significant variable that influences their stress levels and stress control methods. It is thought that students' self-differentiation functions to minimize their stress and to actively cope with their stressful situation and that a high degree of self-differentiation is a significant mediator variable that is beneficial to students' mental health. It follows from the above observations that while college students in this study seem to possess good degrees of self-differentiation and stress coping capabilities and low stress levels they need to seek for the ways to improve their degree of self-differentiation by seeing into themselves and relationships with others around them. Parents, schools and consultation agencies are required to take an active hand to educate and encourage them to cope with their stress positively.

• 한국자동차공학회논문집
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• 제22권6호
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• pp.68-74
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• 2014

This study analyzes structural stress and fatigue about three types of automotive wheels. As maximum equivalent stresses at 1, 2 and 3 types become lower than the yield stress of material and deformations become minute, theses types are thought be safe on durability. Type 2 model has the most fatigue life among three kinds of types and the rest of models with fatigue lives are shown in the order of type 1 and 3. As the most fatigue frequency of type 2 model happens at the state of average stress and amplitude stress on the stress range narrower than type 1 or 3, type 2 model becomes most stable. In case of type 2 with the state near the average stress of 0 MPa and the amplitude stress of 300MPa, the possibility of maximum damage becomes 30%. This stress state can be shown as the most damage possibility. These study results can be effectively utilized with the design on automotive wheel by anticipating and investigating prevention and durability against its damage.