• 기본간호학회지
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• 제14권1호
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• pp.120-127
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• 2007

Purpose: This study was done to identify the level of stress, hardiness, and professional burnout of intensive care unit (ICU) nurses and to provide basic data for the qualitative improvement of nursing work achievement in the workplace. Method: The data were obtained from 129 ICU nurses through a questionnaire. Results: Stress showed positive correlation with the level of professional burnout and there was negative correlation between hardiness and professional burnout. Nurses in the group with a high level of stress, and a high level of hardiness reported a low level of professional burnout compared to those in the group with a lower level of hardiness (t=-2.60, p= .012). Nurses in the group with a low level of hardiness and a low level of stress showed a lower level of professional burnout than those with a high level of stress (t=3.51, p= .001). Conclusion: The results show that the high level of stress when coupled with a low level of hardiness of ICU nurses results in a high level of professional burnout. For this reason, it is important for nursing administration to support nurses to reduce levels of stress and the resulting burnout in ICU nurses.

• 한국식생활문화학회지
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• 제35권5호
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• pp.483-492
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• 2020

Dietary components can modulate stress, inflammatory indicators, and health risk. This study examined the relationship among diet, metabolic disease risk, and perceived stress in Korean adult females using the 2017-2018 Korea National Health and Nutrition Examination Survey. A total of 4,353 adult women aged 19-64 years were classified into four groups according to perceived stress level: very high stress group (VHSG, n=225), high stress group (HSG, n=1,079), moderate stress group (MSG, n=2,532), and low stress group (LSG, n=517). Data collection included the sociodemographics, anthropometrics, blood profile, and dietary survey. After adjusting for covariates, those in the VHSG had a higher body mass index (p=0.013) and obesity rate (p=0.053) with a shorter sleep time than the LSG group. The VHSG also tended to have a higher plasma LDL-cholesterol, hsC-reactive protein and lower levels of HDL-cholesterol, vitamin A, and vitamin E than the low stress group. High stress subjects demonstrated increased breakfast skipping frequency (p<0.0001), decreased fiber intake (p=0.001), potassium (p=0.041), and vitamin A (p=0.011) than the low stress ones. Therefore the perceived stress level was associated with the inflammatory indicators, obesity, and lack of anti-inflammatory or antioxidant nutrients. The dietary components may be an important mediator of stress and metabolic disease.

• International Journal of Naval Architecture and Ocean Engineering
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• 제11권2호
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• pp.671-678
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• 2019

In this paper, the low cycle fatigue failure and ratcheting behavior, as well as their interaction of AH32 steel were experimentally investigated under uniaxial cyclic loading. The effects of mean stress, stress amplitude and stress ratio on the low cycle fatigue life and ratcheting strain were discussed. It was found that the ratcheting strain increased while the fatigue life decreased with the increase of mean stress and stress amplitude, and the increasing stress ratio would result in smaller ratcheting and larger fatigue life. Two kinds of failure modes, i.e. low cycle fatigue failure due to crack propagates and ratcheting failure due to large plastic strain will take place respectively. Based on the experimental results, considered the effect of ratcheting on fatigue life, a model with the maximum stress and ratcheting strain rate was proposed. Comparison with the experimental result showed that the new model provided a good prediction for AH32 steel.

• JSTS:Journal of Semiconductor Technology and Science
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• 제3권3호
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• pp.114-121
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• 2003

Through comparing stress state of TEOS and SiLK-embedded structures, the effect of low-k materials on stress and stress distribution in via-line structures were investigated using three-dimensional finite element analyses. In the case of TEOS-embedded via-line structures, hydrostatic stress was concentrated at the via and the top of the lines, where the void was suspected to nucleate. On the other hand, in the via-line structures integrated with SiLK, large von-Mises stress is maintained at the via, thus deformation of via is expected as the main failure mode. A good correlation between the calculated results and experimentally observed failure modes according to dielectric materials was obtained.

• 동력기계공학회지
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• 제3권2호
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• pp.51-56
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• 1999

Fatigue crack propagation rates and characteristics of the SA516-70 steel which is used for the low temperature pressure vessels, were studied in the room temperature of $10^{\circ}C$ and low temperature ranges of $-10^{\circ}C,\;-30^{\circ}C,\;-50^{\circ}C,\;and\;-70^{\circ}C$ with stress ratio of R=0.05. The obtained experimental results are as follows; 1) In the logarithmic relationship between the fatigue crack propagation rate(da/dN) and stress intensity factor K, the linear relationship was obtained up to da/dN > $8{\times}10^3$ mm/cycle in the same of room temperature, but in low temperature case, the relationship was extended to the range of low crack propagation rate. 2) The lower limit stress intensity factor of SA516-70 ${\Delta}K_{th}\;was\;23MPa\sqrt{m}$ and in the case of low temperature $-50^{\circ}C\;and\;-70^{\circ}C$, the crack propagation rate da/dN which showed a linear relation, reached rapidly to the ${\Delta}K_{th}$. As the results, the crack propagation rates of $-50^{\circ}C\;and\;-70^{\circ}C$ were lower than that of room temperature and according to the testing temperature the rates were decreased rapidly to the ${\Delta}K_{th}$. 3) On the relationship between the stress intensity factor ${\Delta}K$ and the track propagation cycle, the stress intensity factors of low cycle region was rapidly increased at low temperature, but ${\Delta}K$ was increased rapidly at room temperature of high cycle. 4) On the relationship between the fatigue crack propagation rate and cycle, the fatigue crack propagation rate showed higher gradient in the room temperature than the low temperature due to the increment in ductility at low temperature.

• 한국직업건강간호학회지
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• 제25권4호
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• pp.311-319
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• 2016

Purpose: This study examined association of job stress with health-promoting behaviors and objective health status in 129 clinical nurses working at a university hospital. Methods: A cross-sectional and descriptive design was used. Job stress and health behaviors were measured with Korean Occupational Stress Scale and Heath Promoting Lifestyle Profile-II, respectively. Health status measured with afternoon plasma cortisol, C-peptide, and lipid profiles. Results: The level of job stress among clinical nurses was moderate with 51.41 on average. The mean for health-promoting behavior in the low stress group was significantly higher than that in the high or moderate stress groups (p<.001). The proportions of nurses with high C-peptide and cortisol levels, or low high-density lipoprotein levels, ranged from 14.0% to 35.7%. In particular, the percentage of nurses with high C-peptide levels was significantly higher in moderate and high stress groups than in the low stress group (24.1% versus 11.6%, p<.05). Conclusion: The study findings affirmed the associations of job stress with health-promoting behaviors as well as selected health status indicators such as C-peptide in clinical nurses. Job stress management intervention can help clinical nurses to improve their health-promoting behaviors and health status.

• 대한인간공학회지
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• 제19권2호
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• pp.15-31
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• 2000

The aim was to evaluate the prevailing ergonomic and psychosocial conditions regarding low back injury in an automobile assembly system. This study consisted of two parts. In the first part of the study, analytic biomechanical model and NIOSH guidelines were applied to evaluate risk levels of low back injury for automobile assembly jobs. Total of 246 workers were analysed. There were 20 jobs having greater back compressive forces than 300kg at L5/S1. Also, there were 44 jobs over Action Limit with respect to 1981 NIOSH guidelines. This might in part be explained by the ergonomic conditions of the company analysed generally being good, with a relatively low duration of 'combined' extreme work posture. The relationship between psychosocial factors and low back injury was examined in the second part of the study. It has recently been recognized that overall reaction to working conditions was influenced by a range of factors, some of which were physical and some psychosocial. The psychosocial environment surrounding the work place may contribute to the perception of risk and eventual ill-health. A battery of questionnaires concerning the psychosocial stress based on PWI(Psychosocial Well-being Index) and musculoskeletal pain symptoms at low back was completed by 246 workers at the same plant. Results showed that 207 out 246 workers experienced the symptoms and 27 workers were diagnosed as patients. Two groups(low stressed, high stressed) based on PWI score had no significant relationships with both symptoms and results of diagnosis. However, sensitivities for symptoms and diagnosis by PWI were 91.3% and 92.6% respectively. Finally, relationships between physical work load and psychosocial stress were analysed. Specifically, some postural factors {vertical deviation angle of forearm, horizontal deviation angle of upperarm, vertical deviation angle of thigh, etc) were highly correlated with psychosocial stress. The results illustrated that PWI scores were associated with some physical workloads. However, psychosocial stress levels couldn't be well related with the pain symptom as well as the actual incidence of low back injury since pain or discomfort regarding low back injury were more complex than that of other musculoskeletal disorders.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2000년도 추계학술대회 논문집
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• pp.240-245
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• 2000

Fatigue crack propagation rates and characteristics of the SA516-60 steel which is used for the low temperature pressure vessels, were studied in the room temperature of $25^{\circ}C$ and low temperature ranges of $10^{\circ}C,\; -10^{\circ}C,\; -30^{\circ}C,\; -50^{\circ}C, \;and\; -70^{\circ}C4 with stress ratio of R=0.05. The obtained experimental results are as follows; 1) In the logarithmic relationship between the fatigue crack propagation rate(da/dN) and stress intensity factor K, the linear relationship was obtained up to da/dN 〉$8\times10^{-3}$/mm/cycle in the same of room temperature, but in low temperature case, the relationship was extended to the range of crack propagation rate. 2) The lower limit stress intensity factor of SA516-60 $\DeltaK_{th}$ was 15.8MPa and in the case of low temperature $-50^{\circ}C\; and\; -70^{\circ}C$, the crack propagation rate da/dN which showed a linear relation, reached rapidly to the $\DeltaK_{th}$/. As the results, the crack propagation rates of $-50^{\circ}C\; and\; -70^{\circ}C$ were lower than that of room temperature and according to the testing temperature the rates were decreased rapidly to the $\DeltaK_{th}$/. 3) On the relationship between the stress intensity factor $\DeltaK$ and the crack propagation cycle, the stress intensity factors of low cycle region was rapidly increased at low temperature, but $\DeltaK$ was increased rapidly at room temperature of high cycle. 4) On the relationship between the fatigue crack propagation rate and cycle, the fatigue crack propagation rate showed higher gradient in the room temperature than the low temperature due to the increment in ductility at low temperature.

• 센서학회지
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• 제14권5호
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• pp.357-361
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• 2005

Low-stress silicon nitride (LSN) thin films with embedded metal line have been developed as free standing structures to keep microspheres in proper locations and localized heat source for application to a chip-based sensor array for the simultaneous and near-real-time detection of multiple analytes in solution. The LSN film has been utilized as a structural material as well as a hard mask layer for wet anisotropic etching of silicon. The LSN was deposited by LPCVD (Low Pressure Chemical Vapor Deposition) process by varing the ratio of source gas flows. The residual stress of the LSN film was measured by laser curvature method. The residual stress of the LSN film is 6 times lower than that of the stoichiometric silicon nitride film. The test results showed that not only the LSN film but also the stack of LSN layers with embedded metal line could stand without notable deflection.

• Journal of Power Electronics
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• 제13권2호
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• pp.186-196
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• 2013

This paper presents a low voltage-stress AC-linked charge equalizing system for balancing the energy in a serially connected, valve-regulated lead acid battery string using a modular converter that consists of multiple transformers coupled together. Each converter was coupled through an AC-linked bus to increase the overall energy transfer efficiency of the system and to eliminate the problem of the unbalanced charging of batteries. Previous solutions are based on centralized and modularized topologies. A centralized topology requires a redesign of the hardware and related components. It also faces a high voltage stress when the number of batteries is expanded. Modularized solutions use low-voltage-stress, double-stage, DC-linked topologies which leads to poor energy transfer efficiency. The proposed solution uses a low-voltage stress, AC-linked, modularized topology that makes adding more batteries easier. It also has a better energy transfer efficiency. To ensure that the charge equalization system operates smoothly and safely charges batteries, a small intelligent microcontroller was used in the control section. The efficiency of this charge equalization system is 85%, which is 21% better than other low-voltage-stress DC-linked charging techniques. The validity of this approach was confirmed by experimental results.