• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.6
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• pp.519-525
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• 2008

For this study, SM45C steel rods using generally for power transmission shafts and machine components was selected and welded by butt-GMAW method. And then it was studied about estimation of fatigue strength and the region of infinite life by Haigh diagram using Goodman's equation. Fatigue strength in weld zone presents highly in order of the boundary between deposited metal zone and heat affected zone, deposited metal zone, heat affected zone. This result agrees with distribution of hardness in weld zone. Fatigue strength in base metal zone presents highly compared with weld zone in low cycles between $10^4$ cycles and $10^6$cycles, but it presents the lowest fatigue strength on the order of heat affected zone in the vicinity of $10^6$cycles. It is the result that the first high compressive residual stress distributed by drawing process of the steel rods is released and the base metal is softened by alternating stresses. The region of infinite life by Haigh diagram presents highly in order of the boundary between deposited metal zone and heat affected zone, deposited metal zone, heat affected zone. From this results, it is demanded that the stress for safety design of machine components using SM45C butt-welded steel rods must be selected in the region of the lowest infinite life of heat affected zone.

• Journal of the East Asian Society of Dietary Life
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• v.21 no.6
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• pp.838-843
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• 2011

The objective of this study is to evaluate antioxidant activities of Rehmanniae Radix Preparata (RRP) prepared from dried root through nine repeated steaming-drying cycles. The total phenolic content of the final cycle of RRP increased to 165.2% compared with that of the 1st cycling product. Antioxidant activities which were determined by ferric-reducing antioxidant potential (FRAP), 2,2'-azinobis(3 ethybenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging, 1,1-diphenyl-2-picrydrazyl (DPPH), and hydroxyl radical scavenging activities, increased remarkably as the number of steaming-drying cycles increased. Especially, FRAP value increased to 89.1%. Further, $IC_{50}$ values for DPPH and hydroxyl radical scavenging activities of the final 9th-cycling product decreased to 58.3% and 67%, respectively. Based on these results, it was observed that the antioxidant activities of RRP improve according to an increased number of steaming-drying cycles.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.10a
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• pp.25-28
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• 2000

In this paper, the technology for accelerating degradation & life estimation on the traction motor was introduced with the stator form-winding sample coils of the 200 Class insulation system The accelerative degradation was performed in 10 cycles, which were composed of thermal stress, fast rising surge voltage, vibration, water immersion and overvoltage applying. After aging of 10 cycles, condition diagnosis test such as insulation resistance & polarization index, capacitance & dielectric loss and partial discharge properties were investigated in the temperature range of $20{\sim}160^{\circ}C$. Relationship between degradation conditions and diagnosis results were analyzed to find an dominative degradation factor at the end-life point

• Tribology and Lubricants
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• v.13 no.3
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• pp.28-32
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• 1997

Indentation, scratch and sliding tests were carried out in this paper to predict the critical loads and the failure modes of TiN-coated specimen. The test specimens were S20C steels with three different substrate hardness, roughness and coating thickness. The scratch test shows that the coating thickness has more dominant effect on the critical load of coated disk than the hardness and the roughness. Using the percent contact load, the ratio of sliding load to the critical scratch load, the cycles to failure are measured to predict the wear-life of TiN film. On the wear-life diagram the percent loads and the cycle to failure show the good linear relation on semi-log coordinate. With decreasing loads, the diagram shows the wear-limit at which the coated disk survives more than 4000 cycles.

• Journal of Welding and Joining
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• v.26 no.3
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• pp.45-50
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• 2008

SM45C steel rods being used generally for power transmission shafts and machine components was selected and welded by Butt-GMAW(Gas Metal Arc Welding) method. An estimation of fatigue life was studied by constructing S-N curve. Fatigue strength of base metal zone showed higher values than one of weld zone in low cycles between $10^4$ and $10^6$cycles. However, significant decrease in fatigue strength of base metal was found around $10^6$cycles, which were almost same as one of heat affected zone. This decrease was attributed that initial residual stress of the steel rods distributed by drawing process was diminished by continually applied load, and resulted in softening of base metal. The fatigue limit of the weld zone was highest in the boundary between deposited metal zone and heat affected zone, and followed by in the order of deposited metal zone, base metal zone, and heat affected zone. Based on these results, it is revealed that the stress for safety design of machine components using SM45C butt-welded steel rods must be selected within the region of the lowest fatigue limit of heat affected zone.

• Journal of Korean Academy of Nursing
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• v.39 no.3
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• pp.433-445
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• 2009

Purpose: The purpose of this study was to assess changes in pain, fatigue, anorexia, anxiety and quality of life(QOL) in patients with cancer who were on chemotherapy. Methods: Symptoms and QOL were examined both before chemotherapy and after 2 cycles of chemotherapy. The participants were 76 cancer patients receiving chemotherapy in one of 7 hospitals. Results: The patients experienced a mean of 2.22-2.23 symptoms out of 4 symptoms. Patients who were female, or suffered from breast or colorectal cancer experienced more symptoms. Fatigue at present, and most severe fatigue and anorexia in the previous 3 weeks increased significantly. Anxiety and QOL decreased significantly after 2 cycles of chemotherapy. Number of symptoms, anorexia at present, most severe anorexia in past 3 weeks, and anxiety had negative correlations. QOL before chemotherapy showed a positive correlation with QOL after 2 cycles of chemotherapy. In a regression analysis, anxiety, QOL at baseline, income, and the most severe pain in the past 3 weeks were significant predictors of QOL. Conclusion: Physical and psychological factors were significant predictors of both QOL and each subscale, and these factors correlated with each other. These results demonstrate the needs for early assessment and intervention from the start of chemotherapy to decrease symptoms and improve QOL.

• Microbiology and Biotechnology Letters
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• v.21 no.1
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• pp.88-94
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• 1993

Actinomycetes are the most diverse group of bacteria. in variety. morphology. and life cycle. Especially. the variety of genus and species of Actinomycetes is so diverse among other microorganisms that about 50 genus of Actinomycetes have been reported until now. Among them. Streptomyces genus is the most plentiful and over 220 species have been reported. The number of the genus of Actinomycetes will be expected to be fixed to about 55 genus and 250 Streptomyces species in the year 2000 thereabouts. Morphological and physiological characters of Actinomycetes varies with culture condition. and therefore diverse life cycles are also possible. In this paper. life cycles of the representative Actinomycetes, Nocardia, Streptomyces. Kitasatosporia. GeodermatoPhi/us. and Sporichthya. according to the condition of nutrient in the media were reviewed.

• Ocean Systems Engineering
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• v.2 no.2
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• pp.159-171
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• 2012

Reinforced concrete structures in cold coastal regions are subjected to coupled effects of service load, freeze-thaw cycles and seawater corrosion. This would significantly degrade the performance and therefore shorten the service life of these structures. In the current paper, the mechanical properties of concrete material and the structural behaviour of eccentrically loaded reinforced concrete columns under multiple actions of seawater corrosion, freeze-thaw cycles and persistent load have been studied experimentally. Results show that when exposed to alternating actions of seawater corrosion and freeze-thaw cycles, the compressive strength of concrete decreases with the increased number of freeze-thaw cycles. For reinforced concrete column, if it is only subjected to seawater corrosion and freeze-thaw cycles, the load resistance capacity is found to be reduced by 11.5%. If a more practical service condition of reinforced concrete structures in cold coastal regions is simulated, i.e., the environmental factors are coupled with persistent loading, a rapid drop of 15% - 26.9% in the ultimate capacity of the eccentrically loaded reinforced concrete column is identified. Moreover, it is observed that the increase of eccentric load serves to accelerate the deterioration of column structural behavior.

• Journal of Korean Academy of Nursing
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• v.32 no.4
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• pp.482-491
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• 2002

This study aimed to identify the change patterns of fatigue and quality of life during consecutive chemotherapies and to determine the relationship of these two variables. Method: Stomach cancer patients receiving chemotherapy were recruited from a university hospital in Seoul. Each chemotherapy, subjects were asked to respond to the questionnaires regarding their fatigue and quality of life. The number of subjects who completed 4 cycles and over was 11. Fatigue was measured with Lee's tool(1999). Quality of life was measured with a tool revised by the author based on Padilla et al(1983). Result: Most patients were in 1st stage(5 patients) or 3rd stage(5 patients). Fatigue was revealed at its highest level in the 3rd or 4th chemotherapy and at its lowest level in the 1st or 6th chemotherapy. A quality of life appeared at its highest level in the 5th or 6th chemotherapy and the lowest level in 3rd or 4th chemotherapy. Conclusion: Among 6 cycles of chemotherapy, in 3-4th chemotherapy the fatigue was the highest and the quality of life were the lowest. Many patients decided to stop treatment at the same period. Therefore we can recognize cancer patients receiving chemo- therapy are in the highest risk at the time of the 3-4 th chemotherapy.

• Structural Engineering and Mechanics
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• v.73 no.4
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• pp.455-462
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• 2020

The hybrid method using the extended finite element method (XFEM) and the forward Euler approach is widely employed to predict the fatigue life of plate structures. Due to the accuracy of the forward Euler approach is determined by a small step size, the performance of fatigue life prediction of the hybrid method is not agreeable. Instead the forward Euler approach, a prediction method using midpoint method and support vector regression (SVR) is presented to evaluate the stress intensity factors (SIFs) and the fatigue life. Firstly, the XFEM is employed to calculate the SIFs with given crack sizes. Then use the history of SIFs as a function of either number of fatigue life cycles or crack sizes within the current cycle to build a prediction model. Finally, according to the prediction model predict the SIFs at different crack sizes or different cycles. Three numerical cases composed by a homogeneous plate with edge crack, a composite plate with edge crack and center crack are introduced to verify the performance of the proposed method. The results show that the proposed method enables large step sizes without sacrificing accuracy. The method is expected to predict the fatigue life of complex structures.