• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.09a
• /
• pp.990-996
• /
• 2010

In this study, a method for estimating the effective stress of clays using in-situ penetration test(PCPT) result is proposed. The proposed method is based on a correlation between the PCPT results and strength increment ratio. According to proposed method, no additional testing procedure for collecting undisturbed soil sample is required, which can reduce overall testing cost. To verify this method, for analysis, various analytical solutions were adopted and used. Measured and predicted effective stress are compared on the test results. The verification sites consist of a variety of soil condition. From comparison, it is seen that predicted value of effective stress using the propose method match well those from measured results.

• Nuclear Engineering and Technology
• /
• v.53 no.8
• /
• pp.2509-2522
• /
• 2021

A valve assembly used in nuclear power plants must be qualified and supervised. New technical standards such as ASME QME-1 2007 particularly require detailed qualification using experiment and analysis. Particularly, diagnostic tests and engineering studies are required for qualification of ASME QME-1 2007. Among these studies, the research on the measurement of friction coefficient and packing stress is important. The irregular change of packing stress along the stroke distance occurs because of the abnormal phenomenon, which must be found and studied with quantitative methods. Packing stress should be analyzed conservatively through experimentation and analysis. In this study, various formulas were applied to measure and calculate coefficient of friction and packing stress. This study can be used in relation to qualification and supervision of packing materials. And the calculation using static diagnosis test can be used to find the packing frictional force in dynamic diagnosis test with flow pressure in a pipe. This study has made it possible to reliably consider packing frictional force generated in a valve body. And so, it is believed that more margin can be secured when evaluating the capacity of valve actuator by applying the accurate frictional force generated in the valve assembly.

• Journal of Oriental Neuropsychiatry
• /
• v.18 no.1
• /
• pp.1-14
• /
• 2007

Objective : The purpose of this study was to investigate the protective effects of Cheongsimondam-tang(COT) on the animal model of depression induced immobilization stress. Method 1) Male rats were used for this experiment. The subject were divided into 4 groups(1. normal 2. saline solution administered during immobilization stress treatment 3. COT of 100mg/kg administered 4. COT of 400mg/kg administered). 2) Immobilization stress was treated for 1 hours on day. During 2 days of immobilization stress treatment, they were executed forced swimming test, passive avoidance test, elevated plus maze test. Corticosterone in blood were measured Results 1) In EPM test, stress group showed significantly increased anxiety, COT groups showed significantly decreased anxiety. 2) In forced swimming test, COT groups did not show significantly decreased immobilization. 3) In passive avoidance test, stress group showed significantly decreased learning execution, COT groups showed significantly increased learning execution. 4) Stress group showed significantly increase in serum level of corticosterone, COT of 400mg/kg group showed significantly decreased serum level of corticosterone. Conclusion : These results suggest that Cheongsimondam-tang(COT) is effective in the treatment of depression.

• Journal of Oriental Neuropsychiatry
• /
• v.7 no.1
• /
• pp.39-48
• /
• 1996

This study was performed to investigate the effects of Qigong training after physical training stress in untrained college students For this study, 6 voluntary subjects(male 4, female 2) were chosen in untrained students of K University. they were trained by teachers during 6 weeks and tested just before Qingong training and after 6 weeks. Each subject was performed a treadmill exercise(model Q65, Quinton Co, U.S.A.) to the all-out state. During exercise stress test, electrocardiogram, heart rate were checked by stress test monitor(model Q4500, Quinton Co, U.S.A) and also oxygen uptake, maximal oxygen uptake analyzed continuously by automatic gas analysis(model QMC, Quinton Co, U.S.A). During physical training the serum were collected 3 times, pre-experimental rest time, and serum catecholamine were measured by HPLC.T-test of statistical analysis system was used in every experiment for statistical assessment. The results of T-test on these data were summarized as follow:1.Heart rate change during exercise stress test after Qigong training was shown more decreasing tendency than before training. Especially, heart rate change after Qigong training during resting periods was decreased significantly than before training.2. Oxygen uptake change during exercise stress test after Qigong training was shown more increasing tendency than before training, And also maximal oxygen uptake after Qigong training was shown more increasing tendency than before 6 weeks.3. Epinephrine level of after Qigong training was more decreased significantly than before training in all-out state. And norepinephrine level of after Qigong training was shown more decreasing tendency than before training in all-out state and after 30 minutes rest time. Above results indicate that Qigong training for 6 weeks could be effective to elevate the cardiopulmonary functions and diminish the stress responses of the physical stress.

• Journal of Oriental Neuropsychiatry
• /
• v.18 no.2
• /
• pp.45-55
• /
• 2007

Objective : The purpose of this study was to investigate the protective effects of Radix Curcumae on the animal model of depression induced immobilization stress. Method : 1) Male rats were used for this experiment. The subject were divided into 4 groups(1. normal 2. saline solution administered during immobilization stress treatment 3. Radix Curcumae of l00mg/kg administered 4. Radix Curcumae of 400mg/kg administered). 2) Immobilization stress was treated for 1 hours on day. During 2 days of immobilization stress treatment, they were executed forced swimming test, passive avoidance test, elevated plus maze test. Corticosterone in blood were measured. Results : 1) In EPM test, stress group showed significantly increased anxiety, Radix Curcumae of 400mg/kg group showed significantly decreased anxiety. 2) In forced swimming test, Radix Curcumae of 400mg/kg group showed significantly decreased immobilization. 3) In passive avoidance test, stress group showed significantly decreased learning execution, Radix Curcumae groups showed significantly increased learning execution. 4) Stress group showed significantly increase in serum level of corticosterone, Radix Curcumae of 400mg/kg group showed significantly decreased serum level of corticosterone. Conclusion : These results suggest that Radix Curcumae is effective in the treatment of depression.

• Safety and Health at Work
• /
• v.13 no.2
• /
• pp.235-239
• /
• 2022

Background: The purpose of present study was to determine the effectiveness of training program based on job stress management in NEDSA and line staff. Methods: The study method of this study was quantitative and quasi-experimental research Methods: From the statistical population (all employees of the NEDSA and line staff in 2020-2021), 30 of these people were selected by judgmental sampling method and considering the inclusion and exclusion criteria. The participants were first matched based on age and education and were randomly divided into experimental and control groups. First, pre-test was taken from both groups (Job Stress Questionnaire). The experimental group was presented with a job stress management training package and no protocol was presented in the control group. After the sessions, post-test was received from both groups (experimental and control). After two months, a follow-up test was performed. Results: The results were entered into SPSS-24 software and analyzed. The results of repeated measure showed high effectiveness of the job stress management package (researcher-made). The results showed that the job stress management training package showed 67.5% effectiveness and also the training effect of job stress management training was stable for two months (follow-up). Conclusion: Based on these results, Training program based on stress management can be effective in military staff.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.11
• /
• pp.230-235
• /
• 2016

The purpose of this study was to investigate the stress from work and stress coping methods of hospital nurses. The study design was a descriptive survey research. There were a total of 168 hospital nurses included in this study. Data were analyzed by t test, ANOVA (Sheffe's test), and Pearson's correlation coefficient using SPSS/WIN17.0. The stress level from work was 4.27 and stress coping methods was 2.67. Marital status was positively correlated with education level, current department, career duration, and current position. The education level was positively correlated with career period and current position. Current position was positively correlated with stress coping methods. A further follow-up study on nurses in hospital is necessary to relieve stress from work and to increase better stress coping methods. Moreover, to decrease the stress from work of nurses, it is necessary to develop a program that helps them to cope with stress. In addition, these findings contribute to the development of such program.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2008.10a
• /
• pp.292-296
• /
• 2008

A new method of evaluating critical damage values of commercial materials is presented in this paper. The method is based on the previous study of the methodology [1] of acquisition of true stress-strain curves or flow stress curves over large strain from the tensile test in which the flow stress is described by the Hollomon law-like form, that is, by the strain dependent strength coefficient and the strain hardening exponent. The strain hardening exponent is calculated from the true strain at the necking point to meet the Considere condition. The strength coefficient is assumed to be constant before necking and represented by a piecewise linear function of strain after necking. With the predicted flow stress, a tensile test is simulated by a rigid-plastic finite element method with higher accuracy of less than 0.5% error between experiments and predictions. The instant when the fracture begins and thus the critical damage is obtained is determined by observing the stress variation at the necked region. It is assumed that the fracture due to damage begins when the pattern of stress around the necked region changes radically. The method is applied to evaluate the critical damage of a low carbon steel.

• Journal of Families and Better Life
• /
• v.28 no.4
• /
• pp.29-42
• /
• 2010

This study examined the effects of ego-resilience and directors' and fellow teachers' social support on childcare teachers' job stress. The participants were 323 childcare teachers in Chung nam Province and Daejeon Metropolitan City. The research instruments were Job Stress Scale by Cho(2004), Ego-resilience Scale by Park(1996) with CPI and CAQ correction, and Social Support Scale by Park(1985). Collected data were analysed by t-test, F test and Scheff$\acute{e}$ test for post hoc test, Pearson's productive correlation and stepwise multiple regression, and Cronbach's $\alpha$ for reliability by SPSS PC program (17.0 version). The results were as follows: First, the childcare teachers' job stress level was low (M=2.51, SD=.63), while ego-resilience level and social support level of directors and fellow teachers (M=3.68, SD=.58; M=3.62, SD=.94; M=3.83, SD=.69, respectively) were above the average. Second, there were significant differences between different levels of ego-resilience and of social support from directors and fellow teachers. Last, directors' social support and childcare teachers' optimistic attitude of ego-resilience were the most dominant variables that affected childcare teachers' job stress level(R2=38.3% for total score of childcare teachers' job stress).

• Proceedings of the KWS Conference
• /
• 1998.10a
• /
• pp.288-291
• /
• 1998

Inconel 600 alloy is used as the material of nuclear steam generator tubing because of its mechanical properties, formability, and corrosion properties. According to reports, the life time of nuclear power plants decreases because of the pitting, intergranular attack, primary water stress corrosion cracking(PWSCC), and intergranular stress corrosion cracking(IGSCC), and denting in the steam generator. The SCC test is very important because of SCC appears in various environment such as solutions, materials, and stress. The C-Rig specimen was made of the steam generator welded sleeve repairing by the pulsed Nd:YAG laser. In the corrosion invironment, corrosion solutions are Primary Water, Caustic, and Sulfate solution and corrosion time is 1624-4877hr. The permitted stress is 30-60ksi.In this C-Ring SCC test is the relationship between corrosion depth, crack and corrosion environment is evaluated. SCC was happens in Sulfate and Corrosion solution but doesn't happen in Primary Water. The corrosion time and stress is very affected by the severely environment of Sulfate or Caustic solution. The microstructure observation indicates that SCC causes interganular failure in the grain boundary of vertical direction.