• Journal of Korean Association for Spatial Structures
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• v.10 no.3
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• pp.57-64
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• 2010

Uniaxial tensile tests of ETFE membrane are performed in this paper. Three kinds ETFE membrane with different thickness are used in the tests. The tensile strength, the tensile strain at break and the stress-strain curve are obtained from the tests. Futhermore, The cycle loading test of ETFE membrane is carried out through using different values of cycle stress. The residual strain, the relaxation of stress and the change of the elastic modulus of foil are investigated. In the creep test, three kinds of temperature (25, 40 and 60 $^{\circ}C$)and three kinds of stress(3,6and9 MPa) are set respectively and the creep time lasts 24 hours.

• Korean Journal of Adult Nursing
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• v.22 no.2
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• pp.153-160
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• 2010

Purpose: The purpose of this study was to investigate the effects of aromatherapy on stress, fatigue, mood, and vital signs of the nurses in the operating rooms. Methods: The data were collected from September 2007 to February 2008 in the operating room at K hospital located in Seoul, Korea. A total of 48 nurses were recruited. Among them, 25 nurses were randomly assigned to an experimental group and 23 were assigned to a control group. Experimental group was provided with aroma inhalation by necklace which had essential oil mixture of 0.2 cc. For aroma inhalation, Lavender, Zeranium and Mazoram were mixed in ratio of 5:3:2. In order to test the effectiveness of aroma inhalation, the pretest and posttest results for stress, fatigue, mood, and vital signs were compared between the experimental group and the control group. The data were analyzed by unpaired t-test and ANCOVA using the SPSS/WIN 15.0 program. Results: There were statistically significant decreases in the stress and fatigue scores, and increase in the mood scores and showed significant relaxation in the vital signs after the aroma inhalation. Conclusion: The aromatherapy had the positive effects on stress, fatigue, mood, and vital signs.

• Journal of the Korean Society for Railway
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• v.7 no.2
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• pp.85-92
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• 2004

This paper consists of two parts. One is finite element analysis of the redistribution of residual stresses of weld specimen by cutting. This work is necessary to predict the actual residual stress distribution of weld specimens used in fatigue test. The other subject is to calculate the relaxation of residual stress and the strain field induced by cyclic loading. To obtain fatigue life of weldment, the value of strain amplitude at each position is necessary, for example in the strain-life approach, and the numerical results can be used to verify experimental strain measurements. Thermo mechanical finite element analyses were conducted on the commercial package ABAQUS.

• Korean Journal of Food Science and Technology
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• v.24 no.4
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• pp.335-340
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• 1992

The amounts of salt diffused into radish after immersing in various concentrations of salt solution at different temperatures were measured and the changes of radish texture by the salt diffusion were estimated with the viscoelastic constants of a 3 element solid model determined by a stress relaxation test. The amount of salt diffused through radish was increased with increasing the salt concentration and soaking temperature. While the instantaneous stress, equilibrium elastic solid content and viscoelastic constants of radish were decreased as salt concentration and soaking temperature increased, the stress relaxed fast. Viscoelastic constants as well as the diffusivity were influenced by salt concentration more than by soaking temperature. The rheological equations for the predictable stress changes of radish after immersed in the salt solution at various conditions (temperature, salt concentration and impure salt) were suggested as a function of time.

• Archives of Metallurgy and Materials
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• v.64 no.3
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• pp.819-822
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• 2019

Uniaxial tensile tests were performed on porcine skin to investigate the tensile stress-strain constitutive characteristic at quasistatic deformations using uniaxial tensile tests. Experimental results were then used to determine the parameters of the various constitutive model types for rubber, including the Mooney-Rivlin, Yeoh, Ogden, and others. The Prony series viscoelastic model was also calibrated based on the stress relaxation test. To investigate the calibrated constitutive equations (visco-hyperelastic), the falling impact test was conducted. From the viewpoint of the maximum impact load, the error was approximately 15.87%. Overall, the Ogden model predicted the experimental measurements most reasonably. The calibrated constitutive model is expected to be of practical use in describing the mechanical properties of porcine skin.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.4
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• pp.612-618
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• 1998

Monolithic SiC and SiC/C FGM layers were deposited on the graphite substrates by the CVD method and their thermal properties of the two specimens were investigated by thermal shock test for comparison. Temperature profiles and thermal stress distributions on thermal shock test were calculated by a commercially used computer program to see the thermal stress differences inside of two specimens. The specimens coated with FGM were expected to show a efficient relaxation of thermal stresses at the interface and they were not cracked under the actual $\Delta$T=1600 K experimental condition. This result proved that the experimental results were well accorded with the expectation from the theoretical calculations.

• Korean Journal of Adult Nursing
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• v.13 no.2
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• pp.317-326
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• 2001

The purpose of this study was to identify correlation of stress, coping patterns and physical symptoms in cancer patient's caregiver. The stress was measured by VAS(Visual Analogue Scale). The coping methods were measured using the modified Ways of Coping Questionnaire by Yang (1998) and the actual physical symptoms were investigated. The phases of patient illness consisted of 1st (initial) stage, and 2nd (recurred) stage and 3rd (terminal) stage based on literature (Lewandowski & Jones, 1988). The data were collected by a survey conducted from March to July, 2000 and which included 196 cancer patients' caregivers from two hospitals in Seoul. The data were analyzed using paired t-test, unpaired t-test, ANOVA, Scheffe test and Pearson correlation coefficient. The results were as follows: 1. The average of caregivers' stress scores was 62.5. Problem-focused coping methods were significantly used more than emotion-focused coping methods by the cancer patients' caregiver. The mean number of caregivers' physical symptom was 1.03. 2. There were significantly high level of stress in women, those who were more than 60 years old, those who had a low education level, those who had no job, those who are patients' wives' and those who are terminal patients' caregiver. There were significantly low levels of coping in women, those who were more than 60 years old, those who had low education levels, those who had no job and those who are patients' wives. There were significantly higher number of physical symptoms in women, and those who have no job. 3. Caregivers' stress was significantly correlated to problem-focused coping methods (r=-.21, p=.006), and physical symptom (r=-.28, p=.0001). In conclusion, attempts to develop nursing interventions for cancer patients' caregiver in women, those who are more than 60 years old, with a low education level, have no job, and are cancer patients' wives could have an improvement on positive coping methods and provide relaxation from stress in the patients' experience.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.9
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• pp.3284-3288
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• 2010

This experiment, through the use of Ear-Therapy by a Cylindrical bar, analyzed the change of adolescence brain function. For this experiment, from the months of Nov. until Dec. 2009, 41 subjects were selected students the experimental group 21, the comparison group 20 that adolescence lives in Kyonggi-do southern region. pre and post treatment were measured with a paired t-test. The results of study confirmed significant change of mental relaxation quotient. Therefore, this results show that Ear-Therapy is a effective for mental stress reduction and mental relaxation in adolescence brain function.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.05a
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• pp.172-175
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• 2001

The high temperature deformation behavior of two-phase gamma TiAl alloy has been investigated with the variation of temperature and ${\gamma}/{\alpha}_2$ volume fraction. For this purpose, a series of load relaxation tests and tensile tests have been conducted at temperature ranging from 800 to $1050^{\circ}C$. In the early stage of the deformation as in the load relaxation test experimental flow curves of the fine-grained TiAl alloy are well fitted with the combined curves of two processes (grain matrix deformation and dislocation climb) in the inelastic deformation theory. The evidence of grain boundary sliding has not been observed at this stage. However, when the amount of deformation is large (${\epsilon}{\approx}$ 0.8), flow curves significantly changes its shape indicating that grain boundary sliding also operates at this stage, which has been attributed to the occurrence of dynamic recrystallization during the deformation. With the increase in the volume fraction of ${\alpha}_2$-phase, the flow stress for grain matrix deformation increases since ${\alpha}_2$-Phase is considered as hard phase acting as barrier for dislocation movement. It is considered that cavity initiation is more probable to occur at ${\alpha}_2/{\gamma}$ interface rather than at ${\gamma}/{\gamma}$ interface.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.372-377
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• 2002

Residual stress by welding should be reduced because that decreases the reliability on strength of welded structure. The reason is that the total stiffness of structure decreases by non-linear behavior of weldment under external load. The release of residual stress by mechanical loading and unloading is often performed in the fabrication of box structure for steel bridge. The proper degree of loading and unloading is significant at release method of residual stress by mechanical loading because that degree is changed by material and geometric shape of welded structure. Therefore, the simulation model that could exactly analyze the release of residual stress by mechanical loading is to be necessary. This simulation model should be established on the based of variable and accurate measurement data. In this study, the non-linear behavior of weldments under external loading and unloading, such as the decrease and increase of structure stiffness, was investigated by monitoring of nominal stress and strain. Tensile loading and unloading test under variable load was performed and the proper degree of stress relaxation was measured by sectioning technique using strain gauge.