• The Journal of Korean Academic Society of Nursing Education
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• 제12권2호
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• pp.205-213
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• 2006

Purpose: This study was to identify the relationship between clinical stress, self-efficacy, and self-esteem of nursing college students. Method: The data were collected from 172 nursing students in J city. Result: The average scores were; clinical stress 3.56/5, self-efficacy 3.52/5, and self-esteem 3.10/4. Clinical stress level was significantly different according to the general characteristics of clinical tutors(t=2.04, p=.043) and degree of clinical satisfaction(F=6.44, p=.002). Self-efficacy level was significantly different according to the general characteristics of school grade(t=2.29, p=.023) and degree of nursing major satisfaction(F=5.00, p=.008). Self-esteem level was significantly different according to the general characteristics of degree of clinical satisfaction(F=6.56, p=.002) and degree of nursing major satisfaction(F=14.22, p=.000). Self-efficacy level and self-esteem level showed a statistically significant but low positive correlation(r=.171, p=.05). Conclusion: A strategy for development of clinical stress management program is needed for nursing students.

• Journal of Mechanical Science and Technology
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• 제16권2호
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• pp.192-202
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• 2002

In particle or short-fiber reinforced composites, cracking of the reinforcements is a significant damage mode because the cracked reinforcements lose load carrying capacity. This paper deals with an incremental damage theory of particle or short-fiber reinforced composites. The composite undergoing damage process contains intact and broken reinforcements in a matrix. To describe the load carrying capacity of cracked reinforcement, the average stress of cracked ellipsoidal inhomogeneity in an infinite body as proposed in the previous paper is introduced. An incremental constitutive relation on particle or short-fiber reinforced composites including progressive cracking of the reinforcements is developed based on Eshelby's (1957) equivalent inclusion method and Mori and Tanaka\`s (1973) mean field concept. Influence of the cracking damage on the stress-strain response of composites is demonstrated.

• Journal of the Korean Society for Heat Treatment
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• 제13권3호
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• pp.170-176
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• 2000

A novel method for improving the adhesion of diamond films on cemented carbide tool inserts has been investigated. This method is based on the formation of a compositionally graded interface by developing a microrough surface structure using a pulsed laser process. Residual stresses of diamond films deposited on laser modified cemented carbides were measured as a function of substrate roughness using micro-Raman spectroscopy. The surface morphology and roughness of diamond films and cemented carbides were also investigated at different laser modification conditions. It was found that the increasing interface roughness reduced the average residual stress of diamond films, resulting in improved adhesion of diamond films on cemented carbides.

• Magazine of the Korean Society of Agricultural Engineers
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• 제37권3_4호
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• pp.90-98
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• 1995

The recycled concrete, average compressive strength of which was 2l0kg/cm$^2$ or higher with slump range of 14~18cm, was prepared by replacing 25% and 50% by weight of coarse aggregate with recycled aggregate from waste concrete. Mix design method for crushed aggregates was used and all specimens were cured by normal moisture curing method. A plasticiser and a fly ash were added to the mix to improve performance of recycled concrete. Flexural strength, stress- strain relationship and fracture toughness were evaluated by comparing with those of normal concretes. Recycled concrete showed, in general, lower flexural strength and fracture toughness, and higher strain under the same stress level. Fly ash in the concrete had an effect of reducing the strength and fracture toughness on both normal and recycled concretes. Since fly ash is known to improve many properties of concrete, while reducing strength properties, decision for using fly ash should be made carefully depending on the intended usage of the recycled concrete.

• Proceedings of the KWS Conference
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• 대한용접접합학회 2003년도 춘계학술발표대회 개요집
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• pp.216-218
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• 2003

A fracture mechanics analysis methodology for stress corrosion cracks (SCCs) existing in the Alloy 600 nozzle weld joint for control rod drive mechanisms (CRDMs) of pressurized water reactor is studied. Effects of weld residual stresses on the sub-critical crack behavior during the reactor operation are investigated by a fracture mechanics analysis, which is combined with the finite element alternating method. It is found that effects f the residual stresses on the stress intensity factor (SIF) and crack growth rate (CGR) are dominant and values of SIF and CGR of cracks in the region of weld joint are increased by a factor of three or more on an average.

• International Journal of Naval Architecture and Ocean Engineering
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• 제4권2호
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• pp.132-140
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• 2012

This study aims to assess fatigue property by the static overload and average load in the fillet welded joints which is on the ship structural steel having gusset welds. To this end, a small specimen was made, to which the same welding condition for the actual ship structure was applied, to perform fatigue tests. In this study, a method to simply assess changes in welding residual stress according to different static overload was suggested. By measuring actual strain at the weld toe, the weld stress concentration factor and property which is determined by recrystallization in the process of welding were estimated to investigate the relation between overload and fatigue strength.

• Journal of Welding and Joining
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• 제15권4호
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• pp.143-153
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• 1997

In this study, bending test was performed on the real-scale, built-up beam test model fabricated by the $CO_2$ arc spot welding to evaluate the applicability of the welding method to the production of the stiffened plate in car-carrying ship. The built-up beam models which were fixed at both ends in longitudinal direction or simply supported to the rigid foundation, depending on the restraint condition of the corresponding car decks considered, were subjected to simulated design vehicle loads or concentrated point loads. During the test, the central deflection and the longitudinal bending stresses were measured from several points on the longitudinal flange face to predict the section properties of the built-up beams. The longitudinal bending stress on each spot weld were also measured to calculate the average horizontal shear force subjected to spot welds. Test results revealed that the shear strength of spot welds with their current weld nugget size and welding pitch was adequate enough to withstand the horizontal shear forces under the design vehicle loads. Although the built-up beam fabricated by the arc spot welding was a discontinuous beam, its mechanical behavior was well explained by the continuous beam theory using the effective breadth of plate. Based on test results, the criterion for the size of spot weld of which the average shear stress might meet the allowable stress requirement of AWS Code could be established.

• Proceedings of the Korea Concrete Institute Conference
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• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
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• pp.167-172
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• 2002

Nonlinear analysis of the reinforced concrete beam subjected to torsion is presented. Seventeen equations involving seventeen variables are derived from the equilibrium equation, compatibility equation, and the material constitutive laws to solve the torsion problem. Newton method was used to solve the nonlinear simultaneous equations and efficient algorithms are proposed. Present model covers the behavior of reinforced concrete beam under pure torsion from service load range to ultimate stage. Tensile resistance of concrete after cracking is appropriately considered. The softened concrete truss model and the average stress-strain relations of concrete and steel are used. To verify the validity of Present model, the nominal torsional moment strengths according to ACI-99 code and the ultimate torsional moment by present model are compared to experimental torsional strengths of 55 test specimens found in literature. The ultimate torsional moment strengths by the present model show good results.

• Journal of the Korean GEO-environmental Society
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• 제12권11호
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• pp.71-77
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• 2011

Recently, non-destructive stress measurement method using magnetic anisotropy sensor has been applied to the construction site such as steel bridges and steel pipes. In addition, steel rib used in the tunnel construction site was found to be possible to measure the stress by non-destructive method. In this study, steel loading experiments using magnetic anisotropy sensor developed in Japan and strain gauges were conducted to derive stress sensitivity curve for domestic steel SS400. Also, additional steel loading experiments and numerical analysis were performed for evaluation of applicability for non-destructive stress measurement method using magnetic anisotropy sensor. As a result of this study, stress sensitivity curves for domestic steel SS400 were derived using output voltage measured by magnetic anisotropy sensor and average of stress measured by strain gauges depending on the measurement location. And as a result of comparing additional steel loading experiments with the numerical analysis, error level of magnetic anisotropy sensor is around 20MPa. When considering the level of the yield stress(245MPa) of steel, in case of using magnetic anisotropy sensor in order to determine the stress status of steel, it has sufficient accuracy in engineering. Especially, magnetic anisotropy sensor can easily identify the current state of stress which considers residual stress at steel structure that stress measurement sensor is not installed, so we found that magnetic anisotropy sensor can be applied at maintenance of steel structure conveniently.

• Journal of Korean Academy of Nursing
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• 제35권7호
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• pp.1353-1361
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• 2005

Purpose: This study was done to provide fundamental data for developing a depression prediction model by discovering main factors that affect depression in patients who do maintenance hemodialysis. Method: The subjects were 191 patients doing maintenance hemodialysis selected from outpatient dialysis clinics at 9 major general hospitals, The Instrument tools utilized in this study were adapted from depression, fatigue, sleep disturbance, stress, adaptation, symptoms, daily activities, and role limitation and thoroughly modified to verify reliability and validity. The collected data was analyzed with a SPSS-PC 11.0 Window Statistics Program for real numbers, percentage, average, standard deviation, and multiple regression. Results: The correlation factor for depression was (M=2.54) fatigue(M=3.12), sleep disturbance (M=2.82), stress(M=3.04), adaptation(M=2.53), daily activities(M=2.24), symptoms(M=2.37), and role limitation(M=2.24). The strongest factor that affected depression was explained by symptoms of the patients who performed hemodialysis. The analysis of the factors that affected depression revealed a $58.4\%$ prediction in symptoms, stress, role limitation, and adaptation. Conclusion: It has been confirmed that the regression equation model(Depression=7.351 + .266$^{\ast}$symptoms + .260$^{\ast}$stress -.l89$^{\ast}$adaptation + .057$^{\ast}$fatigue) of this research may serve as a prediction factor for depression in Hemodialysis Patients.