• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1388-1393
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• 2003

In this study, analytic stress-displacement solutions are obtained by using a shear lag modeling constructed for the spliced joint area with a splicing gap filled with adhesive material of elastic modulus $E_{a}$ in the fiber metal laminate (FML) which is known to have excellent fatigue, corrosion and fire-flame resistant characteristics while with relatively low densities compared to the conventional aluminum alloys for lightweight structures.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2003.09a
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• pp.147-163
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• 2003

European Union bans the usage of Pb in electronics from July 1 st, 2006. The Near-eutectic Sn-Ag-Cu alloys are the leading candidate Pb-free solders (for SMT card assembly). .The microstructure of Sn-Ag-Cu alloys is discussed in terms of solidification, composition and cooling rate. Methods of controlling Ag3Sn plates are discussed. .Thermo-mechanical fatigue behaviors of Sn-Ag-Cu solder joints are reviewed. Tin pest, whisker growth, electromigration of Pb-free solders are discussed.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.17
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• pp.7137-7139
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• 2014

Background: This systemic analysis was conducted to evaluate the efficacy and safety of pemetrexed based chemotherapy in treating patients with metastatic gastric cancer (MGC) as a salvage chemotherapy. Methods: Clinical studies evaluating the efficacy and safety of pemetrexed based regimens on response and safety for patients with gastric cancer were identified by using a predefined search strategy. Pooled response rates (RRs) of treatment were calculated. Results: In pemetrexed based regimens, 4 clinical studies including 171 patients with advanced gastric cancer were considered eligible for inclusion. Systemic analysis suggested that, in all patients, pooled RR was 25.1% (43/171) in pemetrexed based regimens. Major adverse effects were neutropenia, anorexia, fatigue, and anemia. No treatment related death occurred in pemetrexed based treatment. Conclusion: This systemic analysis suggests that pemetrexed based regimens are associated with mild activity with good tolerability in treating patients with MGC.

• Journal of the Korean Society of School Health
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• v.35 no.3
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• pp.65-74
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• 2022

Purpose: The purpose of the study was to verify the degree of smoking behaviors including conventional cigarettes, electronic cigarettes, and dual use of conventional and electronic cigarettes among adolescents, and to explore associated intrapersonal and interpersonal factors of the three smoking behavior groups. Methods: The secondary data analysis was performed using the 17th 2021 Korea Youth Risk Behavior Survey. The types of smoking behaviors were grouped into conventional cigarettes, electronic cigarettes, and dual use for data analysis. Descriptive statistics and a χ² test were performed. Multinomial logistic regression analysis was conducted to identify factors associated with of the three smoking behavior groups. Results: Among the 54,848 adolescents, 3.6%, 1.2% and 6.2% were involved in conventional cigarettes, electronic cigarettes, and the dual use, respectively. The factors associated with the three types of smoking behaviors were depression, suicidal ideation, having a smoking mother, having smoking brothers or sisters, and having smoking friends. Recovery from fatigue by sleep was associated with the dual use of conventional and electronic cigarettes. Anxiety was associated with conventional cigarettes. Having a smoking father was associated with conventional cigarettes and dual use. Conclusion: A significant number of adolescents were involved in not only the use of conventional or electronic cigarettes, but also dual use of them. Adolescents who had depression, suicidal ideation, having a smoking friend, and having a smoking family member were more likely to be involved in the three types of smoking behaviors. Customized interventions to decrease smoking should be developed considering intrapersonal factors as well as interpersonal factors.

• Korean Journal of Community Nutrition
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• v.1 no.2
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• pp.250-259
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• 1996

The school foodservice(FS) dietitians of conventional, co-management and central kitchen systems were compared for their levels of fatigue degrees in order to examine their work specification but no to diminish their educational roles. One hundred and thirtheen primary schools in Taejon and Chungcheongnam-Do participated in the survey, of which foodservice were consisted of 99 conventional types, 7 comanagement types and central kitchen types. Information was collected about the various working hours dietary behavior and fatigue symptoms of the dietitians. The results of this study were as follows : Among 3 school foodservice types, dietitians spent 8 hours and 16 minutes daily for their for their work on the average. However, the central kitchen type dietitans in cities spent 3 hours more compared to the others. The data from the dietitians' work schedule sheets showed that the 5 parts of dietitian's duties set in the school foodservice laws were not well performed. In the central kitchen type they spent more time for food production whereas in the conventional they spent more time for menu formation and hygiene control. It was found that fatigue levels of school foodservice dietitians were chronic with no difference among foodservice systems or among school locations. Our results indicated that nutrition education in primary schools was almost neglected. It is suggested that the school foodservice should meet all the objectives of school-lunch program even though they saved dietitians' work load more or less. The importance of students to improve their dietary habits could never be overlooked. (Korean J Community Nutrition 1(2) : 250-259, 1996)

• Journal of Welding and Joining
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• v.6 no.2
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• pp.30-39
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• 1988

Generally, as the welded region of weld structures has the incomplete bead and welded deposit which are able to behave like the surface cracks occasinally, there is a high possibility that the fatigue fracture of the weld structures is due to the surface cracks on the wlded region. This study was done to investigate the effects of post weld heat treatment (PWHT) on the fatigue behaviors of the surface crack of the heat affected zone (HAZ) for the multi-pass welds under the repetitive pure bending moment. The obtained results are summarized as follows : 1. The crack grows to the depth direction initially as the number of cylces increase, the amount of crack length is increased for the surface dir3ction and cive versa for the depth direction. 2. The fatigue life is increased in a order of as weld, PWHT specimens and parent. 3. As the number of cycles increase, the crack length is increased to th surface direction. The increase of the depth length is blunted at the center of specimen thickness. 4. The fatigue crack growth of PWHT specimens to the surface direction is dependent upon the holding time and applied stress during PWHT. In order words, the crack growth rate decreases with the holding time and increases with the applied stress during PWHT. 5. As the crack grows, the aspect formed in the course of crack propagation approaches to semicircle for parent and ellipse with the largest semidiameter for PWHT ($1/4hr, 15kgf/mm^2$) 6. At depth direction, it is difficult to apply to the paris' equation because of the scattered data between the crack growth rate and the stress intensity factor range.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.7 no.4
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• pp.103-113
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• 1987

Fatigue tests using a single-peak loading and a two-step loading were carried out to examine the fatigue crack growth behaviar and to find the appropriate analysis method. C-T specimens were made using structural steel SWS58 for the tests. From this, just after a single-peak loading acceleration effect was occured and after some times retardation effect was found. And eminent retardation effect was found after High-Low two-step loading. The transition effect of crack growth due to this variable loading was occured owing to the residual stress and the plastic zone size at the crack tip. And the behaviors of these are well explained by Elber's Crack Closure Model. Also I could find that the Wheeler's Retardation Model is a simple and appropriate theory among analysis methods of fatigue crack growth under the variable loading.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.6
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• pp.1327-1334
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• 1988

In this study rotating bending fatigue tests have been carried out with the deep non-through radial holed notch specimens of low carbon steels(SM 22C). It is investigated that the behaviors of surface and interior fatigue crack propagation and the variations of the shape of the cracked surface on the magnitude of bending stresses. The Obtained results are summarized as follows. (1) The relations between [Crack length] and [Cycle ratio] are expressed by following eq. in the 0.1~0.6 range of N/ $N_{f}$ long[ crack length] = A + B [N/ $N_{f}$ ] In case of surface crack length, values of A and B are uniformed independent upon the magnitude of bending stress, but those are variable according to the magnitude of bending stress for interior crack length. (2) The following eq. is derived on the surface crack propagation rate, bending stress and surface crack length. (dl/dN)=(3.94*10$^{-12}$ ).sigma.$^{4.54}$l (3) Under small stress, interior crack propagation rate increase with the interior crack growth but it decrease for large stress. (4) The shape of cracked surface depends upon the magnitude of bending stress. Under small stress fatigue crack propagates as an semi-ellipse with semi-major axis of surface crack length with semi-major axis of interior crack length for large stress.s.

• Women's Health Nursing
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• v.27 no.3
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• pp.196-208
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• 2021

Purpose: This study aimed to test the efficacy of a nurse-led postpartum self-care (NLPPSC) intervention at reducing postpartum fatigue (PPF) and depressive mood and promoting maternal functioning among first-time mothers in Bangladesh. Methods: A non-synchronized quasi-experimental design was used. First-time mothers were recruited during postpartum and assigned to the experimental or control group (34 each). The experimental group received the NLPPSC in the hospital, a 1-day intervention that focused on increasing self-efficacy. The control group received usual care. Data on PPF, depressive mood, maternal functioning, self-care behaviors, postpartum self-efficacy, and self-care knowledge were collected at postpartum 2 weeks (attrition 23.5%) and 6 weeks (attrition 16.1%). Data were analyzed using descriptive statistics, bivariate statistics, and linear mixed model analysis. Results: One-third (33.3%) of new mothers experienced depressive mood (Edinburgh Postnatal Depression Scale scores of ≥13 points). The NLPPSC intervention was statistically significant in decreasing PPF (β=-6.17, SE=1.81, t=-3.39, p<.01) and increased maternal functioning at postpartum 6 weeks in the experimental group (β=13.72, t=3.73, p<.01) compared to the control. Knowledge was also statistically significant for increased maternal functioning over time (β=.37, SE=.18, t=2.03, p<.05). However, there were no statistically significant differences in depressive mood over time. Conclusion: The NLPPSC intervention was feasible and effective in improving fatigue and maternal functioning in Bangladeshi mothers by postpartum 6 weeks and thus supports implementing the NLPPSC intervention for new mothers after childbirth.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.9
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• pp.1605-1614
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• 1992

The effects of % overload (% O.L), baseline stress intensity factor range (.DELTA. $K_{b}$) and dimension-less crack depth (a/W) are examined for the retardation behaviors after a single overload and high-low block loads in 7075-T73 aluminum alloy. And wheeler model, which is one of the fatigue life prediction models, is modified to predict retardation life using these test results. The retardation cycles( $N_{d}$) increased with a decrease in a/W and an increase in % O.L. and (.DELTA. $K_{b}$) These effects are more severe after high-low block loads than single overload. In the case of single overload, the main mechanisms of the retardation are the crack closure and the relaxation of K due to crack branching. But in the case of high-low block loads, that of the main mechanism is the crack closure caused by the accumulated compressive residual stree at the crack tip, which is related with the contact of fracture surfaces. Test results were multiple regression analyzed and got regressed shaping correction factors, (n)$_{REG}$, as function of %O.L., a/W and (.DELTA. $K_{b}$) Wheeler model is modified by using these (n)$_{REG}$. The number of delay cycles calculated by modified Wheeler model were in good agreement with the test results of this study.y.udy.y.y.y.