• 수산해양기술연구
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• 제26권4호
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• pp.380-386
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• 1990

The high stress, low cycle fatigue test were carried out on HT80 plates with artificial part-through notch. The LBB conditions by the net section stress approach was examined in detail. Finite element methods for the state of deformation were also applied and the results were compared with the results from experiments. From the test results, it was noted that the LBB condition in fatigue test was dependent upon the maximun load change before and after the crack penetration. The LBB criterion By the net section stress approach were slightly dependent on initial crack size. It was shown that the state of deformation can be used to predict whether the component is likely to show LBB condition or they will be broken rapidly.

• Structural Engineering and Mechanics
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• 제30권5호
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• pp.577-592
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• 2008

Laplace-Fourier transform techniques are used to investigate the interaction caused by mechanical, thermal and microstress sources in a generalized thermomicrostretch elastic medium with temperature-dependent mechanical properties. The modulus of elasticity is taken as a linear function of reference temperature. The integral transforms are inverted using a numerical technique to obtain the normal stress, tangential stress, tangential couple stress, microstress and temperature distribution. Effect of temperature dependent modulus of elasticity and thermal relaxation times have been depicted graphically on the resulting quantities. Comparisons are made with the results predicted by the theories of generalized thermoelasticity. Some particular cases are also deduced from the present investigation.

• Advances in materials Research
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• 제8권3호
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• pp.219-235
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• 2019

This research is devoted to analyzing mechanical-thermal post-buckling behavior of a micro-size beam reinforced with graphene platelets (GPLs) based on geometric imperfection effects. Graphene platelets have three types of dispersion within the structure including uniform-type, linear-type and nonlinear-type. The micro-size beam is considered to be perfect (ideal) or imperfect. Buckling mode shape of the micro-size beam has been assumed as geometric imperfection. Modified couple stress theory has been used for describing scale-dependent character of the beam having micro dimension. Via an analytical procedure, post-buckling path of the micro-size beam has been derived. It will be demonstrated that nonlinear buckling characteristics of the micro-size beam are dependent on geometric imperfection amplitude, thermal loading, graphene distribution and couple stress effects.

• International Journal of Advanced Culture Technology
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• 제7권3호
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• pp.103-110
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• 2019

The purpose of this study was to investigate the relationship between psychosocial factors, such as self-esteem, stress coping, and social support, and motivation for change in alcohol dependent inpatients. This study included 179 inpatients in the 7clinics for alcoholic in Chonbuk. For the analysis of the study questions, this study utilized the structural equation modeling. The results show that self-esteem was related to motivation for change with mediating role of problem-focused stress coping strategy in alcohol dependent inpatients. The study also reveal that self-esteem and social support was directly associated with the motivation for change. Based on the findings, the importance of programs to promote self-esteem and the involvement of family and acquaintances in the treatment process has been suggested.

• Structural Engineering and Mechanics
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• 제71권1호
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• pp.37-43
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• 2019

This paper studies application of modified couple stress theory and first order shear deformation theory to magneto-electro-mechanical vibration analysis of three-layered size-dependent curved beam. The curved beam is resting on Pasternak's foundation and is subjected to mechanical, magnetic and electrical loads. Size dependency is accounted by employing a small scale parameter based on modified couple stress theory. The magneto-electro-mechanical preloads are accounted in governing equations to obtain natural frequencies in terms of initial magneto-electro-mechanical loads. The analytical approach is applied to investigate the effect of some important parameters such as opening angle, initial electric and magnetic potentials, small scale parameter, and some geometric dimensionless parameters and direct and shear parameters of elastic foundation on the magneto-electro-elastic vibration responses.

• 한국신뢰성학회:학술대회논문집
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• 한국신뢰성학회 2001년도 정기학술대회
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• pp.273-275
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• 2001

With the continuous advancement in electronics technology, especially the usage of new materials and the introduction of new and immature manufacturing process, stress and time dependent types of physical, chemical and mechanical imperfections are introduced to the electronic hardware. These types of imperfections are called flaws. A reliability stress screening process(RSS) is a process which involves the application of operational and/or environmental stress to electronic hardware on a 100% basis, for the purpose of precipitating inherent, as well as process-induced, flaws while neither destroying nor degrading in a significant way the hardware being stressed.

• 대한전자공학회논문지TE
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• 제37권2호
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• pp.17-24
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• 2000

In this paper, the stress and transient currents associated with the on and off time of applied voltage were used to measure the density and distribution of high voltage stress induced traps in thin silicon oxide films. The transient currents were due to the discharging of traps generated by high stress voltage in the silicon oxides. The trap distributions were relatively uniform new both cathode and anode interface. The trap densities were dependent on the stress polarity. The stress generated trap distributions were relatively uniform the order of 1011~1021[states/eV/cm2] after a stress voltage. It appear that the stress and transient current that flowed when the stress voltage were applied to the oxide was caused by carriers tunneling through the silicon oxide by the high voltage stress generated traps.

• 동의생리병리학회지
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• 제22권1호
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• pp.115-119
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• 2008

This study was done to evaluate the antioxidant effect of Crataegi Fructus (CF) extract on the oxidative stress induced by reactive oxygen species (ROS), The human skin fibroblasts (Detroit 551) were cultured with various concentrations of hydrogen peroxide $(H_2O_2)$. The cytotoxicity of $H_2O_2-induced$ oxidative stress was performed by XTT assay for the cell viability according to the dose- and time-dependent treatment. For the protective effect of CF extract on $H_2O_2-mediated$ oxidative stress, cell viability, lactate dehydroganase (LDH) activity, and ferric thiocyanate (FTC) assay for the inhibitive activity of lipid peroxidation on CF extract were carried out. In this study, $H_2O_2-mediated$ oxidative stress was decreased cell viability dose-, and time-dependent manner and increased LDH activity compared with the control in these cultures. In the protective effect, CF extract increased cell viability and decreased LDH activity on $H_2O_2-mediated$ oxidative stress, especially, CF extract has antioxidant effect by the showing the inhibitive activity of lipid peroxidation by FTC assay. From these results, It is suggested that $H_2O_2-mediated$ oxidative stress was highly toxic, and also, CF extract showed the protective effect on $H_2O_2-mediated$ oxidative stress by showing the increased cell viability, decreased LDH activity and lipid peroxidation inhibition in these cultures.

• 지역사회간호학회지
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• 제28권3호
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• pp.313-323
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• 2017

Purpose: The purpose of this study is to investigate factors affecting social problem-solving ability of alcohol-dependent patients with a focus on gender differences. Methods: Participants were 250 alcohol-dependent people(men 140, women 110) who were living in B, G and Y cities. Data were collected from January 10 to March 31, 2017 using self-report questionnaires. Abstinence self-efficacy, alcohol insight, unconditional self-acceptance, and social problem-solving ability were investigated. For data analysis, t-test, one-way ANOVA, Pearson correlation coefficients and multiple regression were employed. Results: Factors influencing social problem-solving ability for men were unconditional self-acceptance and age. The explanatory power was 28%. Factors influencing social problem-solving ability for women were unconditional self-acceptance, stress, religiousness, age, occupation and abstinence self-efficacy and the explanatory power was 72%. Unconditional self-acceptance and age were significant variables of social problem-solving ability in both men and women. Stress, occupation, religiousness and abstinence self-efficacy were significantly associated with social problem-solving ability in women but not in men. Conclusion: The results suggest that it is necessary to consider gender characteristics in order to develop effective management programs for social problem-solving ability in alcohol-dependent people.

• Nuclear Engineering and Technology
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• 제46권1호
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• pp.101-108
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• 2014

About 40% of reactors in the world are being operated beyond design life or are approaching the end of their life cycle. During long-term operation, various degradation mechanisms occur. Fatigue caused by alternating operational stresses in terms of temperature or pressure change is an important damage mechanism in continued operation of nuclear power plants. To monitor the fatigue damage of components, Fatigue Monitoring System (FMS) has been installed. Most FMSs have used Green's Function Approach (GFA) to calculate the thermal stresses rapidly. However, if temperature-dependent material properties are used in a detailed FEM, there is a maximum peak stress discrepancy between a conventional GFA and a detailed FEM because constant material properties are used in a conventional method. Therefore, if a conventional method is used in the fatigue evaluation, thermal stresses for various operating cycles may be calculated incorrectly and it may lead to an unreliable estimation. So, in this paper, the modified GFA which can consider temperature-dependent material properties is proposed by using an artificial neural network and weight factor. To verify the proposed method, thermal stresses by the new method are compared with those by FEM. Finally, pros and cons of the new method as well as technical findings from the assessment are discussed.