• 한국직업건강간호학회지
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• 제24권3호
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• pp.224-234
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• 2015

Purpose: The purpose of this study was to identify family stress, somatization, social support, depression and its influencing factor among middle-aged workers. Methods: The research was cross-sectional descriptive study. The subjects were 212 middle-aged workers living in Seoul and Gyeonggi-do. Data collection was done from May 21 to 31, 2015 using self-reported structured questionnaires asking about general characteristics, family stress, somatization, social support and depression. Data were analyzed using descriptive statistics, independent sample t-test, one way ANOVA, Pearson's correlation coefficient, stepwise multiple regression with SPSS/WIN 19.0 program. Results: Mean score of family stress was 41.67 (range: 25~125), somatization 17.42 (range: 12~60), social support 69.79 (range: 12~84) and depression 13.01 (range: 0~60) and reported as depression in 34.0%. Social support (${\beta}=-.36$, p<.001), somatization (${\beta}=.28$, p<.001), family stress (${\beta}=.15$, p=.014) had significant association with depression and the most important variable was social support. Conclusion: It is suggested to check social support system in middle aged workers and needed to reinforce social support of community based on the relation of occupational category. Also, it is necessary to legalize the institutional devices to prevent and control depression to ensure industrial safety and disaster prevention.

• Journal of Pharmaceutical Investigation
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• 제37권3호
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• pp.137-148
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• 2007

Using a strain-controlled rheometer [Rheometrics Dynamic Analyzer (RDA II)], the steady shear flow properties of a semi-solid ointment base (vaseline) have been measured over a wide range of shear rates at temperature range of $25{\sim}60^{\circ}C$. In this article, the steady shear flow properties (shear stress, steady shear viscosity and yield stress) were reported from the experimentally obtained data and the effects of shear rate as well as temperature on these properties were discussed in detail. In addition, several inelastic-viscoplastic flow models including a yield stress parameter were employed to make a quantitative evaluation of the steady shear flow behavior, and then the applicability of these models was examined by calculating the various material parameters (yield stress, consistency index and flow behavior index). Main findings obtained from this study can be summarized as follows : (1) At temperature range lower than $40^{\circ}C$, vaseline is regarded as a viscoplastic material having a finite magnitude of yield stress and its flow behavior beyond a yield stress shows a shear-thinning (or pseudo-plastic) feature, indicating a decrease in steady shear viscosity as an increase in shear rate. At this temperature range, the flow curve of vaseline has two inflection points and the first inflection point occurring at relatively lower shear rate corresponds to a static yield stress. The static yield stress of vaseline is decreased with increasing temperature and takes place at a lower shear rate, due to a progressive breakdown of three dimensional network structure. (2) At temperature range higher than $45^{\circ}C$, vaseline becomes a viscous liquid with no yield stress and its flow character exhibits a Newtonian behavior, demonstrating a constant steady shear viscosity regardless of an increase in shear rate. With increasing temperature, vaseline begins to show a Newtonian behavior at a lower shear rate range, indicating that the microcrystalline structure is completely destroyed due to a synergic effect of high temperature and shear deformation. (3) Over a whole range of temperatures tested, the Herschel-Bulkley, Mizrahi-Berk, and Heinz-Casson models are all applicable and have an almostly equivalent ability to quantitatively describe the steady shear flow behavior of vaseline, whereas the Bingham, Casson,and Vocadlo models do not give a good ability.

• 한국해양공학회지
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• 제12권1호
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• pp.39-49
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• 1998

In this work, fatigue tests by axial loading were carried out to investigate the effect of stress ratio on the growth behaviors of surface fatigue crack for SM45C steel and Al 2024-T4 alloy. The growth behaviors of surface crack have been monitored during fatigue process by measuring system attached CCTV and monitor. When the growth rates of surface crack were investigate by the concept of LEFM based on Newman-Raju's .DELTA.K, the dependence of stress ratio appears both SM45C steel and Al 2024-T4 alloy. Therefore, modified stress intensity factor range, .DELTA.K' [=(1+R)/sup n/.DELTA.K] are intorduced to eliminate the dependence of stress ratio. Using .DELTA.K', it is found that the dependence of stress ratio disappears both SM45C steel and Al 2024-T4 alloy.

• 한국강구조학회 논문집
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• 제8권4호통권29호
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• pp.19-29
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• 1996

In this paper, it is presumed that the stress time history was generated by simulation method and investigated compatibility in regard to the reappearance of stress time history. In this procedure, the identified frequency distribution of stress range of the steel railroad bridge varies with the rational values of cut off point and bar width. Thus, we show variable aspect of the equivalent stress range results from change of cut off point and bar width. In addition, we analyze the variable of RMC and RMS model due to the cut off point and bar width of the measured stress history which influencs the prediction of fatigue life in the steel railroad bridge. The simulated stress time history is carried out by the superposition method incorporating the vertical load with rotation moment obtained from the Hermition interpolation function, and compared with developing stress results from measured maxi mum stress. Through this study, we can estimate the remaining fatigue life from a safety point of view and comparative accuracy.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2003년도 추계학술대회 논문집
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• pp.106-111
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• 2003

This study made an experiment On fatigue crack propagation da/dn, stress intensity factor range ${\Delta}K$ respectively in room temperature and in low temperature. And we got the following characteristics from fatigue crack growth test carried Out in the environment of room temperature and law temperature at $25^{\circ}C$, $-60^{\circ}C$, $-80^{\circ}C$, and $-100^{\circ}C$ in the range of stress ratio of 0.3 by means of opening made displacement. The threshold stress intensity factor range ${\Delta}Kth$ in the early stage of fatigue crack growth (Mode I) and stress intensity factor range ${\Delta}K$ in the stable of fatigue crack growth (Made II) was decreased in proportion to descend temperature. It assumed that the fatigue resistance characteristics and fracture strength at law temperature and high temperature is considerable higher than that of room temperature in the early stage and stable of fatigue crack growth region.

• Geomechanics and Engineering
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• 제18권1호
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• pp.97-109
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• 2019

Physical conditions play vital role on the mechanical properties of frozen soil, especially for the temperature and moisture content of frozen soil. Subsequently, they influence the subsidence and stress law of permafrost layer. Taking Jiangcang No. 1 Coal Mine as engineering background, combined with laboratory experiment, field measurements and empirical formula to obtain the mechanical parameters of frozen soil, the thick plate mechanical model of permafrost was established to evaluate the safety of permafrost roof. At the same time, $FLAC^{3D}$ was used to study the influence of temperature and moisture content on the deformation and stress law of frozen soil layer. The results show that the failure tensile stress of frozen soil is larger than the maximum tensile stress of permafrost roof occurring in the process of mining. It indicates that the permafrost roof cannot collapse under the conditions of moisture content in the range from 20% to 27% as well as temperature in the range from $-35^{\circ}C$ to $-15^{\circ}C$. Moreover, the maximum subsidence of the upper and lower boundary of the overlying permafrost layer decreases with the increase of moisture content in the range of 15% to 27% or the decrease of temperature in the range of $-35^{\circ}C$ to $-15^{\circ}C$ if the temperature or moisture content keeps consistent with $-25^{\circ}C$ or 20%, respectively.

• 한국보건간호학회지
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• 제30권1호
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• pp.93-104
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• 2016

Purpose: The purpose of this study was to determine the relationship among infertility stress, depression and Resilience of infertile women during infertility treatment. Methods: As a descriptive study, we surveyed 129 infertile women in 1 fertility center from November 2014 to January 2015. The data was analyzed in SPSS WIn 18.0 program. Results: Infertility stress, depression, and resilience averaged $3.23{\pm}.32$ (range of scale 1~6), $1.42{\pm}.39$ (range of scale 1~4), and $3.45{\pm}.35$ (range of scale 1~5), respectively. There was significant difference in infertility stress by job, abortion experience after pregnancy with infertility treatments, anxiety of high risk pregnancy, burden of pregnancy, important of having child. There was significant difference in depression by job, Economy burden on infertility treatment, burden of pregnancy. Infertility stress had a positive correlation with depression (r=.192. p<.029) Resilience had a negative correlation with depression (r=-.349. p<.001). Conclusion: It is necessary to provide infertile women with the counseling on their infertility stress and depression, and the intervention programs for infertile women is expected to help them cope and adapt with their personal and marital problems, reduce their negative emotions, and thus promote their quality of life.

• Journal of Advanced Marine Engineering and Technology
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• 제25권6호
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• pp.1228-1236
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• 2001

In this study, CT specimens were prepared from ASTH A5l6 steel which was used for pressure vessel plates for moderate and lower temperature service. And we got the fellowing characteristics from fatigue crack growth test carried out in the environment of room and low temperature at $25^{\circ}C$ , $-30^{\circ}C$, $-60^{\circ}C$, $-80^{\circ}C$, $-100^{\circ}C$ and $-120^{\circ}C$ and in the range of stress ratio of 0.1, 0.3 by means of opening mode displacement. At the constant stress ratio, the Threshold stress intensity factor range ΔAKth in the early stage of fatigue crack growth (Region I) and stress intensity factor range $\DeltaK$ in the stable of fatigue crack growth (Region II) was increased in proportion to descend temperature. It assumed that the fatigue resistance characteristics and fracture strength at low temperature is considerable higher than that of room temperature in the early stage and stable of fatigue crack growth region. The straight line slope relation of logarithm da/dN-$\Delta$K in Region II that is, the fatigue clack growth exponent m increased with descending temperature at the constant stress ratio. It assumed that the fatigue crack growth rate da/dN is rapid in proportion to descend temperature in Region II and the cryogenic-brittleness greatly affect a material with decreasing temperature.

• Child Health Nursing Research
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• 제15권4호
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• pp.375-382
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• 2009

Purpose: The purpose of this study was to examine the relation between parenting stress and depression in mothers of infants and verbal abuse. Methods: The data for this study was collected from 174 mothers of infants 12 to 48 months old who either used one of two pediatric clinics or one kindergarten. The instruments used for this study were a self-report questionnaire, PSI (Parenting Stress Index Short Form by Abidin), BDI (Beck Depression Instrument) and Verbal Abuse Measure. Regression analysis was the statistical method used for data analysis. Results: The mean score for depression in the mothers was 14.7 (range: 2-35), for parenting stress, 81.86 (range: 44-142), and for verbal abuse, 37.9 (range: 25-79). There were significant positive correlations for depression, parenting stress and verbal abuse in the mothers. Significant factors influencing verbal abuse were child domain, parent-child domain. Conclusion: The results of this study suggest that there is a need to design interventions and develop programs for depression management and parenting stress for mothers of infants between 12 and 48 months.

• 대한기계학회논문집
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• 제10권1호
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• pp.62-69
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• 1986

본 연구에서는 표면균열의 전파거동에 관한 연구의 일환으로 경량화재료 로서 항공기 구조용으로 널리 사용되고 있는 7075-T651 알루미늄합금을 준비하고 제하탄성 compliance법을 이용하여 표면 및 깊이 방향의 균열진전거동의 특성을 밝히고져 한다.