• 근관절건강학회지
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• 제25권2호
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• pp.75-83
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• 2018

Purpose: The purpose of this study is to investigate the effects of an 8-week aquatic exercise program on risk factors of metabolic syndrome and stress in women. Methods: This study employed a non-equivalent control group pretest-posttest design. A total of 35 patients were recruited through a community health center. The data were analyzed with the SPSS 22.0 version program, and the outcome variables were risk factors of metabolic syndrome including abdominal circumference, triglyceride, high density lipoprotein cholesterol, blood pressure, fasting blood glucose, and the level of stress. Results: There was no statistically significant differences in abdominal circumference, triglyceride, high density lipoprotein cholesterol, and blood pressure difference (post-pre) between the experimental and control group. However, there was a significant difference in the stress level. Conclusion: This study result support the beneficial effect of stress management in women on risk reduction for metabolic syndrome. Health professionals consider to develop strategy of the aquatic exercise program to reduce factors of metabolic syndrome.

• Physical Therapy Rehabilitation Science
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• 제11권4호
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• pp.598-603
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• 2022

Objective: About one-third of college students are exposed to stress to the point that their academic performance is negatively affected. To provide useful information for managing the mental health of young people by analyzing the perceived stress level, depression level, and life satisfaction according to the amount of physical activity and the level of muscular strength in male college students. Design: A cross-sectional study. Methods: Among 304 students who participated in the health exercise class at Sahmyook University in Seoul, the amount of physical activity and the level of muscular strength were divided into 3 quartiles, respectively, and the perceived stress level, depression level, and life satisfaction were analyzed through one-way ANOVA. The physical activity level and muscle strength level of the subjects were ranked, divided into 3 groups, and the difference in variables according to the group was verified. Results: There was no difference in perceived stress level, depression level, and life satisfaction according to the amount of physical activity, but statistically significant differences were shown in perceived stress scale(p=0.008) and life satisfaction(p=0.030) according to muscular strength. Conclusions: Policies to increase physical activity are important to improve and manage the mental health of young people, but it is judged to be more meaningful to provide an environment that can improve muscular strength.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집A
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• pp.186-191
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• 2001

Tensile residual stress happen by difference of coefficients of thermal expansion between fiber and matrix is one of the serious problems in metal matrix composite(MMC). In this study, TiNi alloy fiber was used to solve the problem of the tensile residual stress as the reinforced material. TiNi alloy fiber improves the tensile strength of composite by occurring compressive residual stress in matrix using shape memory effect of it. Pre-strain was added to generate compressive residual stress inside TiNi/A16061 shape memory alloy(SMA) composite. It was also evaluated the effect of compressive residual stress corresponding to pre-strains variation and volume fraction of TiNi alloy. AE technique was used to clarify the microscopic damage behavior at high temperature and the effect of pre-strain difference of TiNi/A16061 SMA composite. In addition, two dimensional AE source location technique was applied to inspect the crack initiation and propagation in composite.

• 대한기계학회논문집A
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• 제26권2호
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• pp.275-282
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• 2002

Tensile residual stress happen by difference of coefficients of thermal expansion between fiber and matrix is one of the serious problems in metal matrix composite(MMC). In this study, TiNi fiber was used to solve the tensile residual stress as the reinforced material. TiNi fiber improves the tensile strength of composite by occurring compressive residual stress in matrix using shape memory effect of it. Pre-strain was added to generate compressive residual stress inside TiNi/A16061 composite. It was also evaluated the effect of compressive residual stress corresponding to pre-strains variation. AE technique was used to clarify the microscopic damage behavior at high temperature and the effect of pre-strain difference of TiNi/A16061 shape memory alloy composite.

• 대한기계학회논문집A
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• 제27권5호
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• pp.724-733
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• 2003

Fatigue design rules for welds in the ASME Boiler and Pressure Vessels Code are based on the use of Fatigue Strength Reduction Factors(FSRF) against a code specified fatigue design curve generated from smooth base metal specimens without the presence of welds. Similarly, stress intensification factors that are used in the ASME B3l.1 Piping Code are based on component S-N curves with a reference fatigue strength based on straight pipe girth welds. But the determination of either the FSRF or stress intensification factor requires extensive fatigue testing to take into account the stress concentration effects associated with various types of component geometry, weld configuration and loading conditions. As the fatigue behavior of welded joints is being better understood, it has been generally accepted that the difference in fatigue lives from one type of weld to another is dominated by the difference in stress concentration. However, general finite element procedures are currently not available for effective determination of such stress concentration effects. In this paper, a mesh-insensitive structural stress method is used to re-evaluate the S-N test data, and then more effective method is proposed for pressure vessel and piping fatigue design.

• 소성∙가공
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• 제13권6호
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• pp.497-502
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• 2004

The shape of cold rolled steel sheets is defined as the degree of flatness, and the flatter, the better. Because undesirable strip shapes of cold rolled steel sheets can affect not only visible problem but also automatic working process in customer's lines, the requirement of the customers is more and more stringent. So we usually used the tension leveler to make high quality of strip flatness. For the improvement of the quality of strip flatness, this report developed three- dimensional FEM (Finite Element Method) simulation model, and analysis about the strain and stress distribution of strip in the tension leveling process. The numerical study can be summarized as follows. (1) If we pass the edge wave material (steepness: $1.0\%$) that the stress-difference between the strip center and the edge is 5.2kgf through tension leveler. the stress-difference is decreased 0.45kgf and the steepness is improved to $0.29\%$. (2) If the Intermesh is increased from 6mm to 7mm, the steepness is improved from $0.294\%$ to $0.268\%$. (3) If the initial steepness is decreased form $1.0\%$ to $0.75\%$, the final steepness is improved from $0.294\%$ to $0.263\%$. We know that more increased intermesh and lower initial steepness make the final steepness improved.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.72-77
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• 2001

Tensile residual stress happen by difference of coefficients of thermal expansion between fiber and matrix is one of the serious problems in metal matrix composite(MMC). In this study, TiNi fiber was used to solve the tensile residual stress as the reinforced material. TiNi fiber improves the tensile strength of composite by occurring compressive residual stress in matrix using shape memory effect of it. Pre-strain was added to generate compressive residual stress inside TiNi/A16061 composite. It was also evaluated the effect of compressive residual stress corresponding to pre-strains variation. AE technique was used to clarify the microscopic damage behavior at high temperature and the effect of pre-strain difference of TiNi/A16061 shape memory alloy composite.

• 성인간호학회지
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• 제14권4호
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• pp.581-590
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• 2002

Purpose: The purpose of this correlational study was to identify relationships among job stress, health beliefs and health behaviors of aircrews and contributing factors to aircrew's health promoting behaviors. Method: Two-hundred twenty-four aircrew members completed questionnaires. The questionnaires were composed of a demographic form, health behavior scale, self-efficacy scale, perceived benefit scale, perceived barrier scale, job demand scale, and latitude scale. Result: The subject's health behavior has shown significant correlations with self-efficacy, benefit, and barrier. Significant negative correlations were found between job stress and self-efficacy. Relationships between job stress and barriers were also statistically significant. In demographic features, statistically significant difference were found between subject's rank and job stress score. Also, there was a significant difference between health behavior and the subject's age. Conclusion: Future efforts should focus on the development of a program to consider aircrew's perceived benefits, perceived barriers and self-efficacy to the compliance of health promoting behaviors.

• Tribology and Lubricants
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• 제31권5호
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• pp.189-194
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• 2015

This paper focuses on the conformal contact problem. A typical example of conformal contact is the contact between a pin and hole. In particular, this paper focuses on the condition for assuming a contact stress field to be a Hertzian pressure profile by using well-known classical solutions associated with Hertzian contact. Persson first developed the conformal contact analysis method around half a century ago, but there have been no significant improvements since then. The present research also adopted this method, but developed new solutions from the viewpoint of application to structural design. The analysis began with a comparison between Persson°Øs conformal contact stress and the Hertzian stress fields. The next step was to check the differences in the normalized stress values of both. This study used the tolerance for the difference in the peak stresses of Persson°Øs solution and the Hertz solution to validate the Hertzian assumption. This gave the range for the difference in radii of the pin and hole when the contact force and mechanical properties of the material are specified. The results showed that, at a tolerance of 5%, the Hertzian assumption is valid if half of the contact angle is less than 35°ý. In addition, the Hertzian assumption holds even for a relatively long contact length, in contrast to the general incomplete contact problem. This paper discusses these results along with other aspects of the application to the design.

• 성인간호학회지
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• 제20권3호
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• pp.431-442
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• 2008

Purpose: The purpose of this study was to examine the effects of resistance exercise program for elders with type 2 Diabetes on the self care, stress and HbA1c. Methods: Thirty three elders with type 2 Diabetes(18 experimental and 15 control subjects) were selected conveniently among the aged who had been enrolled in a community senior center. The subjects in experimental group participated in a resistance exercise program for 8 weeks. Data were analyzed using the SPSS/Win 12.0. Results: The resistance exercise program showed a statistical difference in self care(t=-4.39, p=.000) and stress(t=2.22, p=.034). However, there was not a statistical difference in HbA1c (F=.556, p=.557), but experimental group had decreased continuously in HbA1c after the program. Conclusion: The resistance exercise program improved self care and reduced the stress in the elders with type 2 Diabetes. Therefore, resistance exercise program can be applied as an effective nursing intervention to promote self care, decrease the stress and to prevent complication for the elders with type 2 Diabetes.