• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.296-301
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• 2004

By the purpose to investigate the change of internal stress and mobile dislocation density in creep, the stress relaxation test is carried out in the condition of each strain. Mobile dislocation density increased until it reached minimum creep rate and after that, it decreased and internal stress didn't have the change approximately until it reached minimum creep rate and after that, it decreased. The stress relaxation rate is fast and approached zero after 1.5 seconds after the beginning of the stress relaxation. And the larger the applied stress is, the larger the internal stress is. By the evaluation of mobility of dislocation, the dislocations glide viscously in STS31OJlTB but it is the dislocations glide viscously which N passes by cutting Cr atom rather than typical viscosity movement after calculating mobility of dislocation.

• 대한기계학회논문집A
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• 제29권2호
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• pp.214-219
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• 2005

To investigate the change of internal stress and mobile dislocation density in the creep, stress relaxation test was examined from each strain range. Mobile dislocation density increased until it reached minimum creep rate but after that, it decreased. Internal stress did not change until it reached minimum creep rate but after that, it decreased. The stress relaxation rate is fast and approached zero later 1.5 seconds, which were begun in the stress relaxation. When the applied stress is large, the internal stress is large. It is cleared that dislocations glide viscously which N passes by cutting Cr atom rather than typical viscosity movement by the evaluation of mobility of dislocation in STS310J1TB.

• Child Health Nursing Research
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• 제7권3호
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• pp.383-396
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• 2001

This study was designed to investigate the effects of the progressive muscle relaxation on behavioral states and emotional reactions of adolescent athletes. The participants were 167 adolescent male soccer players aged between 12 and 18 who were junior or high school students in Seoul. Ninety-three of them were assigned to the experimental group, while seventy-four to the control group. The experimental group was treated by 10 sessions (20 min./session) of Jacobson's progressive muscle relaxation for two weeks, while the control group was not treated. The self and observer reported behavioral states, general stress by visual analogue scale, physical symptoms of stress, athletic stress, state anxiety, depression, self-esteem were measured before and after two weeks of the progressive muscle relaxation. The results were as follows ; 1. The self and observer reported behavioral states were significantly decreased in the experimental group compared with the control group. 2. The general stress and the gastrointestinal symptoms of stress were significantly decreased in the experimental group compared with the control group. No significant difference on athletic stress was found between the two groups. The depression and the state anxiety were significantly decreased in the experimental group compared with the control group. The self-esteem was significantly increased in the experimental group compared with the control group. 3. The influential factors on behavioral state of adolescent male athlete were depression and state anxiety. The accelerating factor on behavioral state change after the progressive muscle relaxation was state anxiety. These results are suggested that the progressive muscle relaxation could be effective in stabilizing behavioral state, decreasing general stress, gastrointestinal symptoms of stress, depression, state anxiety, in increasing self-esteem of adolescent male athletes. And the behavioral state change after the progressive muscle relaxation was influenced by state anxiety.

• 한국정밀공학회지
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• 제26권11호
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• pp.85-91
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• 2009

A lip seal is widely used not only to prevent leakage of fluids from an actuator or a rotating shaft but also to exclude outside substances. Recently, TPU(Thermoplastic Polyurethane), which is one of the sealing materials, has been frequently used due to its excellent mechanical properties and wear resistance. The material constants for finite element analysis through the experiment on stress relaxation are presented. The reaction forces of a shaft as well as the contact pressures of a lip seal under condition before and after stress relaxation using finite element analysis were obtained, The results show that stress relaxation has not a little effect on the performance of a lip seal.

• 대한기계학회논문집A
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• 제28권9호
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• pp.1328-1336
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• 2004

According to our fatigue tests carried out at 20 Hz, R=0.1 on transversely butt-welded joints, fatigue strengths of as-welded specimens, that is, specimens having residual stress are higher than those of annealed specimens in short life range, but vice verse in long life range. This behavior seems to be concerned mainly with residual stress relaxation by applied loading. After analyzing the welding process, we conducted finite element analysis to quantify the degree of residual stress relaxation. By taking into account residual stress relaxation, modified Goodman diagram, and nominal stress, we evaluated the fatigue life of the welded joint from the S-N curve for the parent material. The estimated results are in a good agreement with the experimental results.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.108-113
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• 2004

According to our fatigue tests carried out at 20 Hz, R=0.1 on transversely butt~welded joints, fatigue strengths of as-welded specimens, that is, specimens having residual stress are higher than those of annealed specimens in short life range, but vice verse in long life range. This behavior seems to be concerned mainly with residual stress relaxation by applied loading. After analyzing the welding process, we conducted finite element analysis to quantify the degree of residual stress relaxation. By taking into account residual stress relaxation, modified Goodman diagram, and nominal stress, we evaluated the fatigue life of the welded joint from the S-N curve for the parent material. The estimated results are in a good agreement with the experimental results.

• 지질공학
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• 제10권3호
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• pp.217-223
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• 2000

화강암의 결을 형성하는 미세균열은 화강암의 장기적인 거동을 지배하는 중요한 요소이다. 본 연구에서는 일본 이바라끼현 쯔꾸바지방에 분포하는 세립질 이나다 화강암을 대상으로 조사선법을 이용하여 미세균열을 측정하고, 수침 봉압하에서 응력완화시험을 수행할 수 있는 시스템을 개발하여 시험을 실시하였다. 일축압축강도의 약 75% 응력수준에서 실시한 시험결과에 의하면 시험개시 10시간 이내에 총 완화응력의 39%~49%가 발생하였으며, 시험개시 190시간 이내에 10~24 MPa의 응력완화를 보였다. 또한 재하방향에 평행하게 분포하는 미세균열의 밀도가 높을수록 완화응력은 크게 발생하였다.

• 동의신경정신과학회지
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• 제17권3호
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• pp.57-65
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• 2006

Objectives: The purpose of this research is to investigate the effects of Benson's Relaxation Technique on autonomic nervous system for normal subjects with Heart Rate Variability(HRV) and find out relationship with anti - stress effects. Methods: First, Benson's Relaxation Technique was applied on 5 normal subjects for three weeks. Then HRV was examined for 15 minutes Benson's Relaxation Technique application. Next, Benson's Relaxation Technique each 8 times was applied on 5 normal subjects for 1 weeks. Then :HRV was examined each 5 minutes before and after Benson's Relaxation Technique application. Results: 1. SDNN, SDSD increased continuously in HRV for three weeks Benson's Relaxation Technique application. 2. Mean HRV, SDNN, SDSD were significant different in HRV between before and after Benson's Relaxation Technique application at fourth week. Conclusion: The results suggest that Benson's Relaxation Technique application have shown anti-stress effects and the more Benson's Relaxation Technique is repeated, the more effective.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2006년도 춘계학술대회 논문집
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• pp.191-194
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• 2006

Recently the quality improvement of the steel cord product is demanded by the tire market. After wire drawing process, produced residual stresses have a harmful effect on the durability of the wire and become the cause which decreases the quality of the product. Therefore, to improve the quality of the steel cord product, the research regarding the method of residual stress relaxation is necessary. To evaluate the quality of the drawn wire, it is important to measure the residual stress, because the residual stress decides a variety of the quality level which is demanded in the drawn wire. This study proposed a residual stress relaxation method in the drawn wire using FE analysis. The validity of the analysis results was verified by nanoindentation test.

• 한국세라믹학회지
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• 제32권7호
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• pp.793-798
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• 1995

The relaxation of the intrinsic stresses in the diamond films fabricated by the hot filament CVD was studied, and it was confirmed that the tensile intrinsic stresses in the films could be controlled without any degradation in the quality of the diamond films. The tensile intrinsic stresses in the films decreased from 2.97 to 1.42 GPa when the substrate thickness increased from 1 to 10mm. This result showed that the residual stress was affected by the substrate thickness as well as by the interaction between grains. Applying of ＋50 V between the W filament and the Si substrate during deposition, the tensile intrinsic stress in the film deposited at 0 V was decreased from 2.40 GPa to 0.71 GPa. Such large decrease in the tensile intrinsic stress was due to $\beta$-SiC which acted as a buffer layer for the stress relaxation. However, the application of the large voltage above ＋200V resulted in the change of quality of the diamond film, and nearly had no effect on relaxation in the tensile intrinsic stress.