• Proceedings of the Korean Geotechical Society Conference
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• 1991.10a
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• pp.255-270
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• 1991

In recent years. finite element methods have been used with increasing effectiveness in analysis of displacements and stresses within soil masses. However, one of the weakest links in the analytical representations used in these methods is the models of the material behaviour. Herein is discribed a modification to the finite element methods that allows solution problems with realistic stress-strain relation for soils. A finite element program for the precision prediction of the stress distribution within foundation has been developed using the elasto-plastic Work-Hardening model. The developed program is verified by comparing the results of this study with the tested results for Sacramento river sand. The main results obtained from the numerical examples are as follows: The vertical total stress increments are insensitive to drainage and constitutive equation of materials. The horizontal total stress increments are considerably affected by the drainage and constitutive equation of materials. The maximum shear stresses are affected by the drainage only in elasto-ptastic meterirals. The excess pore water pressures and the volumetric strains not only are considerably affected by the constitutive equation of materials. but also have almost similar distribution.

• Journal of Microbiology and Biotechnology
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• v.27 no.7
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• pp.1257-1265
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• 2017

The present study was carried out to investigate the antioxidative and neuroprotective effects of sea buckthorn (Hippophae rhamnoides L.) leaves (SBL) harvested at different times. Reversed-phase high-performance liquid chromatography analysis revealed five major phenolic compounds: ellagic acid, gallic acid, isorhamnetin, kaempferol, and quercetin. SBL harvested in August had the highest total phenolic and flavonoid contents and antioxidant capacity. Treatment of neuronal PC-12 cells with the ethyl acetate fraction of SBL harvested in August increased their viability and membrane integrity and reduced intracellular oxidative stress in a dose-dependent manner. The relative populations of both early and late apoptotic PC-12 cells were decreased by treatment with the SBL ethyl acetate fraction, based on flow cytometry analysis using annexin V-FITC/PI staining. These findings suggest that SBL can serve as a good source of antioxidants and medicinal agents that attenuate oxidative stress.

• Research in Community and Public Health Nursing
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• v.13 no.4
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• pp.618-628
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• 2002

The purposes of this study were to identify patterns and trends of nursing studies of workers' stress conducted in Korea over the last two decades, and to suggest the direction of future research activities. Research studies of workers' stress were collected from the abstract and the title lists of studies using internet search. The total number of studies used for this study was 118. The analysis of these studies showed that the studies of workers' stress have increased rapidly since 1995, but most of them were non-experimental design studies. They tended to be conducted more on nurses, and used confusedly in stress terms. Instruments developed by the authors were the most popular. Moreover, the organizational variables of the stress-related concept were barely used except nurses' stress. Therefore, it was needed to identify and clarify the terms of stress among the authors, and to develop the workers' stress management programs and examine their effects. Especially studies that include the organizational variables of workers' stress need to be done in the future.

• Journal of Korean Academy of Nursing
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• v.38 no.3
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• pp.410-419
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• 2008

Purpose: The purpose of this study was to develop a stress measurement scale for Korean nursing students. Methods: Sixty preliminary items were selected by classifying 229 basic items extracted via literature review and Q-sorting method. In order to verify the reliability and validity of the preliminary instrument, data were collected from 617 nursing students in 2 colleges of nursing in Korea. Results: As a result of the item analysis, 58 items were selected. They consisted of 2 types of stress which were college-based stress (38 items) and clinical-based stress (20 items). Ten factors in college-based stress and four factors in clinical-based stress were extracted by factor analysis, and each had a total variance of 63.01%, and 64.93%. Cronbach's Alpha of those 58 items were .937 in college-based stress and .922 in clinical-based stress, which was high. Conclusion: This paper is meaningful in a way that it has developed a tool capable of measuring stress for nursing students, which reflects the characteristics of our country. It is recommended for further study to re-verify the relevance and stability of this measurement.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.6
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• pp.166-174
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• 2013

This study investigates the strength durability on the results of structural and vibration analysis due to the shape of excavator wheel. As model 2 has the least stress by comparing three models with maximum equivalent stress, model 2 has most durability among three models at static analysis. Maximum equivalent stress is shown at the bottom part contacted with ground and this part on wheel is most affected by load in cases of all models. Safety factor can be decided with the value of 2.3 by considering the yield stress of this model. The range of maximum harmonic response frequencies becomes 6900 to 7000Hz. As model 2 has the least total deformation and equivalent stress at these critical frequencies, model 2 has the most durability at vibration analysis among three models. The structural and vibration analysis results in this study can be effectively utilized with the design of excavator wheel by investigating prevention and durability against its damage.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.4_2
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• pp.541-547
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• 2022

Before making a prototype, we predicted the inlet/outlet differential pressure and flow coefficient, which are the most basic design data for the valve through the design and numerical analysis of the trim, which is the most important in the localization development of the 1500Ib high differential pressure control valve used for boiler feed water. As a result, the design value and the analysis value were found to be about 98% similar. The flow field within the fluid velocity of 23m/s to prevent cavitation was also found. The result of the numerical analysis on thermal stress due to the characteristics of valves exposed to high temperatures showed that it was found to be about 18% less than the allowable stress of the bolt fixing the trim. When all loads such as pressure, self-weight, and vibration are applied, however, it is judged to go beyond the currently calculated thermal stress, exceeding the allowable stress.

• Journal of Korean Academy of Nursing
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• v.44 no.3
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• pp.339-349
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• 2014

Purpose: This study was done to develop a measurement for stress experienced by patients with schizophrenia during hospitalization. Methods: The preliminary tool was developed through in-depth interviews and a validity verification test of content. For data collection, 15 inpatients with schizophrenia were selected as participants for in-depth interviews and 195 patients admitted to one of eight psychiatric hospitals in four provinces were recruited as participants to test reliability and validity of the preliminary tool. Results: The questionnaire was developed as a four-point Likert-type scale in a self-report form with 28 items. Factor analysis showed 28 items in six factors. Factors were named 'Unjust human rights infringement', 'Futureless life', 'Alienation from other family members', 'Infringement of basic needs', 'Infringement of personal preference' and 'Inconvenience of shared living'. The six factors explained 63.5% of the total variance. Cronbach's alpha for the total items was .93 and for the factors ranged from .65 to .87. Conclusion: A tool to measure stress in patients hospitalized with schizophrenic was developed based on identified hospitalization stress experiences. Study results indicate that this tool can be used to evaluate hospitalization stress in these patients and will contribute to establishing nursing interventions for relief of hospitalization stress.

• Korean Journal of Health Education and Promotion
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• v.33 no.1
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• pp.33-40
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• 2016

Objectives: The study aimed to determine the prevalence of and the relationship between stress and musculoskeletal symptoms among undergraduate students. Methods: The convenience sampling method was used for this cross-sectional survey that was conducted from June 16, 2014 to June 21, 2014. A total of 223 subjects (88 men, 135 women) participated in the study and completed a comprehensive self-administered questionnaire requesting information on demographics, medical history, lifestyle, and musculoskeletal symptoms. The Depression Anxiety Stress Scale (DASS) was also administered to the subjects. A total of 223 subjects from 12 universities completed the questionnaires; the data obtained was used for the final statistical analysis. Results: Women had a higher prevalence of stress and musculoskeletal symptoms. Adjusting for sex and age, subjects who were stressed had a 2.85-fold higher risk of musculoskeletal symptoms than subjects who were not stressed. Stratified analyses by sex also showed that women had a higher risk of musculoskeletal symptoms (Modified OR 2.98, 95% CI 1.38-6.45). Conclusions: We found a positive association between stress and musculoskeletal symptoms in undergraduate students; sex differences were present. Further dose-response relationship between stress and musculoskeletal symptoms will be identified by a longitudinal study with a larger sample size.

• Women's Health Nursing
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• v.20 no.1
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• pp.38-47
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• 2014

Purpose: This study aimed to identify related factors of prenatal depression by stress-vulnerability and stress-coping models for pregnant women. Methods: A cross-sectional survey design with a convenience sampling was used. A total of 107 pregnant women who visited a general hospital in a metropolitan city were recruited from August to October, 2013. A structured questionnaire included the Korean version of Beck Depression Inventory II, and the instruments measuring Self-Esteem, Marital Satisfaction, Pregnancy Stress, Stressful Life Events, and Coping. The data were analyzed using descriptive statistics, t-test, Parson's correlation analysis, and stepwise multiple regression. Results: The mean score of prenatal depression was $11.95{\pm}6.2$, then showing 19.6% with mild depression, 15.0% with moderate depression, and 0.9% with severe depression on BDI II scale. Prenatal depression had positive correlation with pregnancy stress (r=.55, p<.01), stressful life events (r=.26, p<.01) and negative correlation with self- esteem (r=-.38, p<.01), marital satisfaction (r=-.40, p<.01), and coping (r=-.21, p<.05). Factors of pregnancy stress, self-esteem, stressful life events, and planned pregnancy explained 38% of the total variance of prenatal depression. Conclusion: These findings show that health providers need to assess prenatal depression and to control the influencing factors.

• Journal of Korean Clinical Nursing Research
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• v.23 no.3
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• pp.398-406
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• 2017

Purpose: The purpose of this study was to evaluate food carving among hemodialysis patients and to identify factors affecting the food carving. Methods: A descriptive correlational study was conducted. Data were collected from 129 patients receiving hemodialysis between March 15 and April 15, 2017. Measurement instruments included the general food craving questionnaire trait, the center for epidemiological studies-depression scale, and stress response inventory-modified form. The statistical analysis included t-test, analysis of variance, pearson correlation analysis, and stepwise multiple regression analysis. Results: Mean food craving score was $53.00{\pm}12.36$. Food craving was higher in patients younger than 40 years (F=4.36 p=.006) and having occupation (t=2.18 p=.031). Patients receiving hemodialysis demonstrated higher levels of depression ($21.37{\pm}9.62$) and stress ($39.68{\pm}15.95$). Factors influencing food craving were depression (${\beta}=.52$, p<.001), stress (${\beta}=.65$, p<.001), and age 50~59 years old (${\beta}=-.28$, p=.001) and 60~69 years old (${\beta}=-.19$, p=.026), which accounted for 25.6% of total variance. Conclusion: Food craving among hemodialysis patients was influenced by patients' depression, stress and age. Assessment and management of depression and stress needs to be incorporated as a nursing strategy for dietary management for hemodialysis patients.