• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.10
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• pp.24-31
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• 2006

In this paper, mechanical behavior of unidirectional composites with flexible matrix was predicted by geometrical non-linear finite element analysis. Two typical idealized unit cells of square and hexagonal fiber arrays were modeled and these were subjected to different loadings. The stress-strain behavior of composites was predicted from which the effective properties were calculated. The hyperelasticity of polyurethane matrix was considered using Mooney-Rivlin model. In result, the stress-strain behavior of flexible composites shows non-linearity, especially it is remarkable under transverse normal and shear loading conditions. In this cases, there are great difference between square and hexagonal fiber array models.

• Journal of Ginseng Research
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• v.33 no.3
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• pp.219-222
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• 2009

Various somatic symptoms are known to be related to stress in a general population. Korean red ginseng has been used as a therapeutic agent for the treatment and prevention of many diseases in Oriental medicine. There exist no data, however, on the effect of Korean red ginseng on somatic symptoms in a general population. In this study, 21 normal subjects were randomly assigned to the Korean-red-ginseng group, and 18 subjects to the placebo group. The subjects took 3 g Korean red ginseng or placebo every day for three weeks. After the three-week treatment, there was a interaction effect of a greater reduction in the Symptom checklist-90-revised (SCL-90-R) somatization score (p=0.04) in the Korean-red-ginseng group. This study suggests that Korean red ginseng is effective for the management of somatic symptoms in a general population.

• Korean Journal of Health Education and Promotion
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• v.29 no.3
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• pp.103-114
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• 2012

Objectives: The purpose of this study was to investigate the relationship between mental health status, stress, coping ability, and coping strategies of college students. Methods: The questionnaires were handed out to 162 college students in the Gyeonggi province. Data was collected using the Symptom Checklist-90-Revised (SCL-90-R) scale of the 90 items, the 'Person in the Rain' drawing test, and the 20-item coping strategies questions. Results: 17.3% of the respondents were belonged to the groups of abnormal or abnormal tendency in the mental health status according to the Global Severity Index (GSI) scores. The clinical/border groups were more commonly used in the 'emotion-focused' coping strategies compared to the normal group. This difference was also statistically significant. Both coping resource and coping ability were significantly associated with the mental health status. Conclusions: These findings suggest that future intervention for effective coping strategies should be carefully designed to promote better mental health among college students. It is also important to detect problematic and weak student's behaviors in the early stages.

• The Korea Journal of Herbology
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• v.23 no.1
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• pp.63-74
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• 2008

Objectives : This study has been carried out to understand the effect of Uncooked Korean Food(F-DM) on blood glucose and antioxidant enzyme activities in streptozotocin-induced Diabetic Rats. Methods : SD rats were separated into four groups(each with 20 rats). Except normal two group, the other two groups were injected into intra-peritoneal with streptozotocin 60 mg/kg. Experimental group was eated Feed with 25% F-DM for 4 weeks. The change of plasma glucose level, body weight were observed. After 4 weeks, liver and kidney weight, antioxidant enzyme activities, survival rate were observed with histological changes on liver, kidney and pancreas. Results : In experimental group, body weight and survival rate increased, plasma glucose level were decreased significantly. Liver and kidney weight, XOD activity were decreased in experimental group compared to control group. GSH-px and CAT activities, insulin- immunoreactive granules in p-cells were increased significantly in experimental group compared to control group. Conclusions : This study shows that the F-DM might be effective for treatment of diabetes and its complications, as well as reduction of the oxidative stress.

• Structural Engineering and Mechanics
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• v.57 no.2
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• pp.295-313
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• 2016

In this study, the three-dimensional finite element method is used to determine the stress intensity factor in Mode I and Mixed mode of a centered crack in an aluminum specimen repaired by a composite patch using contour integral. Various mesh densities were used to achieve convergence of the results. The effect of adhesive joint thickness, patch thickness, patch-specimen interface and layer sequence on the SIF was highlighted. The results obtained show that the patch-specimen contact surface is the best indicator of the deceleration of crack propagation, and hence of SIF reduction. Thus, the reduction in rigidity of the patch especially at adhesive layer-patch interface, allows the lowering of shear and normal stresses in the adhesive joint. The choice of the orientation of the adhesive layer-patch contact is important in the evolution of the shear and peel stresses. The patch will be more beneficial and effective while using the cross-layer on the contact surface.

• Structural Engineering and Mechanics
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• v.44 no.6
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• pp.815-837
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• 2012

A plated beam is strengthened by bonding a thin plate to the tension face; it often fails because of premature debonding of the thin plate from the original beam in a brittle manner. A sound understanding of the mechanism of such debonding failure is very important for the effective use of this strengthening technique. This paper presents an improved analytical solution for interfacial stresses that incorporates multiple loading conditions simultaneously, including prestress, mechanical and thermal loads, and the effects of adherend shear deformations and curvature mismatches between the beam and the plate. Simply supported beams bonded with a thin prestressing plate and subjected to both mechanical and thermal loading were considered in the present work. The effects of the curvature mismatch and adherend shear deformations of the beam and plate were investigated and compared. The main mechanisms affecting the distribution of interfacial stresses were analyzed. Both the normal and shear stresses were found to be significantly influenced by the coupled effects of the elastic moduli with the ratios $E_a/E_b$ and $E_a/E_p$.

• Advances in materials Research
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• v.6 no.4
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• pp.317-328
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• 2017

In this paper, an improved theoretical solution for interfacial stress analysis is presented for simply supported concrete beam bonded with a sandwich FGM plate. Interfacial stress analysis is presented for simply supported concrete beam bonded with a sandwich plate. This improved solution is intended for application to beams made of all kinds of materials bonded with a thin plate, while all existing solutions have been developed focusing on the strengthening of reinforced concrete beams, which allowed the omission of certain terms. It is shown that both the normal and shear stresses at the interface are influenced by the material and geometry parameters of the composite beam. A numerical parametric study was performed for different simulated cases to assess the effect of several parameters. Numerical comparisons between the existing solutions and the present new solution enable a clear appreciation of the effects of various parameters. The results of this study indicated that the FGM sandwich panel strengthening systems are effective in enhancing flexural behavior of the strengthened RC beams.

• Journal of the Korean Geotechnical Society
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• v.23 no.10
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• pp.57-64
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• 2007

Since matric suction of unsaturated soil was related to soil and ground water contaminations, it is very important to analyze its mechanism that was represented by shear characteristics. In three phases of soil, a little air makes the condition of unsaturated soil on contract or shrinkage surface between water and air. Capillarity and suction in pore of unsaturated soil cause surface tension and surface force so it makes negative pore water pressure and increases effective stress as a result. Therefore, negative pore water pressure in partially saturated soil affects the soil structure and degree of saturation and it is important to evaluate accurately unsaturate flow and behavior. In this study, the shear strength characteristics of the seven sandy soils were investigated using consolidated drained triaxial tests with special emphasis on the effects of the negative pore pressure and the matric suction. These tests involved shearing under either a constant net confining pressure and varying matric suction or under a constant matric suction and varying net normal stress.

• Journal of Korean Biological Nursing Science
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• v.24 no.1
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• pp.26-35
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• 2022

Purpose: The purpose of this study was to investigate the influencing factors on health-related quality of life according to body mass index (BMI) in middle age people. Methods: Using the 2017 Korea Health Panel Data, a total of 4,711 subjects age 40-64 were selected and classified into four groups based on BMI levels (underweight, normal weight, overweight, obese). Influencing factors according to BMI in middle age people was analyzed using multiple regression. Results: Activity limited was the most influential factor for health-related quality of life in middle age people. Walking and stress were factors influencing health-related quality of life in all weight groups. In the overweight and obese group, suicidal impulse was a significant influencing factor on health-related quality of life. Conclusion: To improve the health-related quality of life of middle age people, effective walking and stress management for maintaining and managing health, as well as managing suicide risk in the overweight group and obese group are required.

• Steel and Composite Structures
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• v.51 no.1
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• pp.63-72
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• 2024

This study delves into the interaction dynamics between lateral notches and inclusions, providing valuable insights for more effective engineering of structural components. By employing the finite element method, the research analyzes how inclusions affect the dimensions and contours of the plastic zone under confined plasticity conditions. Several parameters were investigated, including loading influence, the distance between the inclusion and notch tip, inclusion stiffness, and the distribution of Von Mises stress, as well as normal stresses σxx and σyy, and Comparison between different stresses. Examining stress distributions under varying loading conditions reveals a significant intensification, particularly near the crack tip. Moreover, the presence of an inclusion near the notch base reduces both the size and shape of the plastic zone. The distribution of the stresses for different loads knows an increase in intensity, especially near the crack head, which is the most requested by the tensile forces on its upper part, which can cause either the crack's initiation or opening, inducing significant stresses.