• Proceedings of the KSME Conference
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• 2008.11a
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• pp.85-87
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• 2008

DMWs are common feature of the PWR in the welded connections between carbon steel and stainless steel piping. The nickel-based weld metal, Alloy 82/182, is used for welding the dissimilar metals and is known to be susceptible to PWSCC. A round-robin program has been implemented to benchmark the numerical simulation of the transient temperature and weld residual stresses in the DMWs. To solve the round-robin problem related to Pressurizer Safety & Relief nozzle, the thermal elasto-plastic analysis is performed in the DMW by using the FEM. The welding includes both the DMW of the nozzle to safe-end and the SMW of the safe-end and piping. Major results of the analyses are discussed: The axial and circumferential residual stresses are found to be -88MPa(225MPa) and -38MPa(293MPa) on the inner surface of the DMW; where the values in parenthesis are the residual stresses after the DMW. Thermo-mechanical interaction by the SMW has a significant effect on the residual stress fields in the DMW.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 1993.11a
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• pp.2-2
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• 1993

The present status of the thennomechanica1 evaluation of functionally gradient materials(FGMs) for space plane application was reviewed, in which research activities and the cooperation of the national project team organized to study FGM science were demonstrated. The project team was divided into three working groups; de singing, processing and evaluation, each of which had their own tasks in the project cooperation. The testings details of the various thennomechanical tests for the FGM samples fabricated by the processing groups were described, along with their corresponding heating conditions of the real environments in the space plane application. For small-sized samples, laser beam heating test and burner heating test were well applied to study the heat shielding and heat resisting properties. Arc-heated wind tunnel test and high temperature!high velocity gas flow test were used for large-sized panel assemblies having cooling structures. The criteria for the evaluation of the heat shielding and heat resisting properties of the FGMs, as well as a crack activation mechanism in their differential temperature heating, were proposed on the basis of the observation in the burner heating test.

• Korean Journal of Materials Research
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• v.17 no.2
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• pp.115-120
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• 2007

Polycrystalline silicon (poly-Si) thin film transistors (TFTs) might be fabricated on the mica substrate and transferred to a flexible plastic substrate because mica can be easily cleaved into a thin layer. To overcome the adhesion and stress problem between poly-Si film and mica substrate, a buffer layer consisting of $SiO_x/Ta/Ti$ three layers has been developed. The $SiO_x$ layer is for electrical isolation, the Ti layer is for adhesion of $SiO_{x}$ and mica. and Ta is for stress relief between $SiO_x$ and Ti. A TFT was fabricated on the mica substrate by a conventional Si process and was successfully transferred to a plastic substrate.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.5
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• pp.118-123
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• 2001

Most structures of automobile are composed of many substructures connected to one another by various types of mechanical joints. In automotive engineering, it is important to study these connected structures under various dynamic farces for the evaluations of fatigue life and stress concentration exactly. It is rarely obtained the accurate load history of specified positions because of the errors such as modeling, measurement, and etc. In the beginning of design, exact load data are actually necessary for the fatigue strength and life analysis to minimize the cost and time of designing. In this paper, the procedure of practical dynamic load determination is developed by the combination of the principal stresses of F.E. analysis and experiment. Inverse problem and least square pseudo inverse matrix are adopted to obtain an inverse matrix of analyzed stresses matrix. Pseudo-Practical dynamic load was calculated for Lab. Test of sub-structure. GUI program(PLODAS) was developed for whole of above procedure. This proposed method could be extended to any geometric shape of structure.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.25 no.4
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• pp.245-252
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• 2016

Girth gears are applied in the mining, cement, and mineral processing industries and used in various types of horizontal mills, rotary dryers and kilns, and other heavy-gear ring applications. The large ring gears are normally fitted outside mills or kilns to provide the primary rotational drive. Recently, an external pinwheel gear set (e-PGS) was introduced to overcome manufacturing problems associated with girth gears. e-PGS is also suitable for low-speed, heavy-duty mechanical transmission and dusty and poor-lubrication conditions. This paper first presents a new profile modification of root relief for the e-PGS cam pinion. We then investigate load-stress factors to estimate the surface fatigue life by varying the shape design parameters. The results show that the contact fatigue life of an e-PGS can be extended significantly by increasing the profile shift coefficient. However, support bearing life of the pinwheel depends more on the contact force distribution than the profile shift coefficient.

• Journal of the Korean Society of School Health
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• v.27 no.2
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• pp.100-108
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• 2014

Purpose: The purpose of this study is to examine the effects of clinical art therapy programs utilized at schools on adolescents' suicidal thoughts and stress relief and to validate their effectiveness as a type of adolescent suicide prevention program. Methods: 12 sessions of clinical art therapy for youth suicide prevention were provided, once a week for 90 minutes, for 20 students at five middle schools in Seoul who were at high risk of committing suicide. By using the paired sample t-test, the study presented qualitative data on the analysis of pre- and post- questionnaires and on the subjects' EEG test and saliva test. Results: First, through the clinical art therapy program, the subjects' happiness index improved significantly while their scores of depression and suicidal ideation (suicidal thoughts) decreased. Second, in the EEG and saliva test conducted after the art therapy sessions, emotional stability increased and stress was reduced significantly. Third, according to the results of pre- and post- K-HTP tests and individual activities, the subjects started to recognize the seriousness of suicide and show emotional stability and positive changes in overall attitudes, valuing the rights and life of their own 'precious selves' (self respect). Conclusion: The results of this study indicate that the clinical art therapy program is significantly effective at preventing suicidal ideation by reducing suicidal impulses and depression, by increasing the happiness index, which can serve as a protective factor against suicide, and by increasing emotional stability while reducing stress. Based on the results, there is a need to develop policy measures regarding art therapy programs which can be utilized at schools.

• The Journal of the Korea Contents Association
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• v.20 no.1
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• pp.684-691
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• 2020

This study was attempted to provide basic data for health promotion program for depressive relief by grasping the degree of depression of adult women and grasping the factors affecting depression. Data were collected using structured questionnaire for 249 adult women in the one marine city and analyzed through technical statistics, Pearson correlation coefficients and multiple regression analysis. According to the study, 76.3 percent (190 people) of women in the city were depressed. The subjects who expressed depression showed negative correlations with social support, self-respect and subjective euphoria and between depression and stress as positive correlation. The result of multiple regression analyses to identify the effects of depression have shown that stress is a major influencing factor, and this model has a 21.1% explanatory power. Therefore, the study found stress as a significant factor in the depression of adult women, it is necessary to develop and apply health promotion programs that can reduce stress in order to reduce depression in adult women.

• Journal of Korean Medicine for Obesity Research
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• v.12 no.2
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• pp.8-16
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• 2012

Objectives: This study is designed to report the correlation between Body Mass Index(BMI), Heart Rate Variability(HRV), stess, drinking alcohol, coffee and smoking. Methods: From 1st January 2010 to 31st December 2012, We tested on 458 patients who hospitalized in Cheong Yeon Korean Medicine Hospital for reducing their weights, then we collected the statistical analysis with the result of their HRV and the special survey. Results: This experiment was studied on total 458 patients, 27 were men and 431 were women. The average of the age of men was $28.23{\pm}4.22$ and $24.31{\pm}385$ was women. There were significant differences in BMI, Low frequency(LF), High frequency(HF), stress score, frequency of drinking alcohol, smoking and drinking coffee followed by their ages. When we looked at the correlation between obesity with smoking and drinking coffee, we can see that the BMI increased, the frequency of drinking alcohol was decreased, however there were no statistic correlation in smoking and drinking coffee with BMI. Conclusions: With the result of HRV, we can suggest the BMI and stress score are correlated each other but we need further studies about passive stress relief by taking favourite food such as drinking alcohol, smoking, drinking coffee, etc.

• Psychiatry investigation
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• v.15 no.11
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• pp.1071-1078
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• 2018

Objective We developed easily accessible imagery-based treatment program for patients with post-traumatic stress disorder (PTSD) related to workplace accidents and investigated the effects of the program on various PTSD related symptoms. Methods The program was based on an online platform and consisted of eight 15-min sessions that included script-guided imagery and supportive music. Thirty-five patients with workplace-related PTSD participated in this program 4 days per week for 4 weeks. Its effects were examined using self-report questionnaires before and after the take-home online treatment sessions. Results After completing the 4-week treatment program, patients showed significant improvements in depressed mood (t=3.642, p=0.001) based on the Patient Health Questionnaire-9 (PHQ-9), anxiety (t=3.198, p=0.003) based on the Generalized Anxiety Disorder seven-item (GAD-7) scale, and PTSD symptoms (t=5.363, p<0.001) based on the Posttraumatic Stress Disorder Check List (PCL). In particular, patients with adverse childhood experiences exhibited a greater degree of relief related to anxiety and PTSD symptoms than those without adverse childhood experiences. Conclusion The present results demonstrated that the relatively short online imagery-based treatment program developed for this study had beneficial effects for patients with workplace-related PTSD.

• Journal of Korean Society of Rural Planning
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• v.27 no.1
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• pp.71-83
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• 2021

This study conducted a survey and analysis of saliva cortisol and psychological questionnaire in order to find out the psychological and physiological changes according to the experience of the care farm targeting fire-fighters. In the program to experience care farms, the total cortisol concentration as a stress hormone decreased after participation, and there was a statistically significant difference (z = 2.858, p <.01). As a result of the risk distribution analysis of the level of post-traumatic stress symptoms of firefighting officials who participated in the program to experience care farms, the high-risk group was found to be as high as 31.2%. In addition, the relative explanatory power of the independent variables that influence the loyalty of the care farm experience activity was found to have an effect in the order of program satisfaction, age, and reliability, and among them, program satisfaction was found to be the most influential variable. Therefore, it is believed that the care farm experience activities as the application of the healing program will have a positive effect on the activation of care farms in each region and the relief of stress symptoms of fire-fighters.