• Transactions of Materials Processing
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• v.7 no.2
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• pp.158-167
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• 1998

Hot restoration mechanism flow stress and stain of the Al2024 composites reinforced with 1,8,15,36, and $44{\mu}m\;SiC_p$(10 vol. %) were studied by hot torsion tests. The hot restoration mechanism of all the composites was found to be dynamic recrystallization(DRX) at $320^{\circ}C$ while that of the composites reinforced with 1 and $8{\mu}m\;SiC_p$ was found to be dynamic recovery(DRX) at $480^{\circ}C$. It was found that the Al2024 composite with $15{\mu}m\;SiC_p$ showed the highest flow stress(${\sim}$223 MPa) at $320^{\circ}C$ under a strain rate of 1.0/sec. Also the highest flow strain of the composites was obtained at $430^{\circ}C$. The com-posites reinforced with 1 and $8{\mu}m\;SiC_p$ showed lower flow stress and higher flow strain at $480^{\circ}C$ than those of the composites reinforced with 15, 36, and $44\;{\mu}m\;SiC_p$ These result were discussed in relation to the transition of the hot restoration mechanism. $DRX{\leftrightarrow}DRV$. The dependence of flow stress on strain rate and temperature was attempted to fit with the hyperbolic sine equation ($\dot{\varepsilon}=A[sinh({\alpha}{\cdot}{\sigma}_p]^n$ exp(-Q/RT)and Zener-Hollomon parameter($Z=\;\dot{\varepsilon}\;exp(Q/RT))$.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.2
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• pp.286-290
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• 2012

The majority of laboratory animals were transported from commercial breeders to a research facility by ground transportation. During the transportation, many biological functions and systems can be affected by stress. In this experiment, the change of body weight during the transportation was measured and the recovery periods from the transportation stress established based on the body weight changes. Total 676 laboratory animals which were aged between 3 to 9 wk old were studied. The transportation time taken from container packing to unpacking the container was approximately 24 h. The temperature of animal container was constantly maintained by air-conditioning and heating equipment. Rats were found to be more sensitive than mice. The body weight of rats was significantly decreased 3.71% (p<0.05) compared to the body weight of mice which decreased 0.9% There was no significant difference between the strains in the same species. When the changes of body weights were compared between delivery days, C57BL/6 mice showed the most variable changes compared to other species and strains. Consequently, C57BL/6 was more sensitive to stress than the other strains and the transportation process needs to be standardized to reduce between day variability. To establish the recovery periods from transportation stress, the body weight changes were measured during the acclimation period. Although the body weight of animals decreased during transportation, animals recovered their weight loss after the next day.

• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.1
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• pp.10-18
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• 2016

In this study, an efficient clamp is proposed to reduce the switch voltage stress of a forward converter. The proposed clamp consists of a conventional LC snubber, a tertiary winding, and a diode. When the switch is turned OFF, the magnetizing inductor energy of the transformer is recovered directly into the flyback output, which is the tertiary winding and diode network, instead of circulating in the LC snubber. Therefore, switch voltage stress and circulating current caused by the magnetizing inductor energy are reduced. This condition improves the efficiency of the forward converter with limited switch voltage stress. A theoretical analysis and the design guidelines of the proposed converter are provided. Experimental results are also reported.

• Steel and Composite Structures
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• v.31 no.1
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• pp.43-51
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• 2019

This paper is concerned with the numerical calculation of mixed-mode stress intensity factors (SIFs) of 2-D isotropic functionally graded materials (FGMs) by the natural element method (more exactly, Petrov-Galerkin NEM). The spatial variation of elastic modulus in non-homogeneous FGMs is reflected into the modified interaction integral ${\tilde{M}}^{(1,2)}$. The local NEM grid near the crack tip is refined, and the directly approximated strain and stress fields by PG-NEM are enhanced and smoothened by the patch recovery technique. Two numerical examples with the exponentially varying elastic modulus are taken to illustrate the proposed method. The mixed-mode SIFs are parametrically computed with respect to the exponent index in the elastic modulus and external loading and the crack angle and compared with the other reported results. It has been justified from the numerical results that the present method successfully and accurately calculates the mixed-mode stress intensity factors of 2-D non-homogeneous functionally graded materials.

• Journal of Korean Academy of Nursing
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• v.5 no.2
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• pp.29-37
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• 1975

The purpose of this study was to measure the extent of stress existing in hospitalized patients which might play an important part in delaying recovery of patients. The study was conducted July l0th through 16th, 1975; a total of 146 patients from 2 general hospitals in Seoul were sampled. Questionnaire, formulated by the researcher, were used to gather necessary information concerning stress in accordance with the physical, psychological, economical and social variables. Data were analysed by mean stress score, and the significances were tested by Critical Ratio. The results were as follows ; 1. No significant difference was revealed in accordance with sex, however, male patients showed higher stress scores on the economic variables. 2. No. significant difference was apparent in accordance with marital status, however, the unmarried showed a tendency of higher stress scores at all variables. 3. Significant difference was revealed between the age group of 35-49 years and that of over 50 years; the age group of 18-34, and 35-49 years showed higher stress scores. 4. No. significant difference was revealed in accordance with previous experience of hospitalization, however, the group with previous experience tends to show higher stress scores in all variables. 5. No significant difference was revealed in accordance with the types of admission, however, group admitted on emergency showed higher stress scores compared to the group admitted plained in advance at social and economic variables. 6. No significant difference was revealed in accordance with the length of hospitalization, however, tendencies were apparent that the longer the length of hospitalization, the lower the mean stress scores.

• Journal of Service Research and Studies
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• v.6 no.4
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• pp.1-13
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• 2016

Emotional labor may lead to service failure in service industries. Managers of an organization or a company can contribute to service recovery by reducing stress related to emotional labor. The aim of this study is to identify the antecedents and consequences of service recovery in respect of emotional labor. Data was surveyed from frontline employees to achieve the research purpose. The hypotheses were examined empirically using statistical tools. Results are as follows. First, surface acting had a negative impact on service recovery performance and deep acting had a positive impact. Second, empowerment and motivation had an influential relationship positively on service recovery performance. Third, service recovery performance was negatively related to intention to quit. In conclusion, managing employees' emotional labor strategies and work environment will bring high service recovery performance and low intention to quit.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.5 no.1
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• pp.107-124
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• 1998

Based on King's goal attainment theory, this research deals with applying nursing intervention of mutual goal settings to gastrectomy patients. It tests the effects of nursing intervention, according to the patients' health locus of control, suggested as external boundary criteria for the theory by employing a quasi-experimental design which consists of a pretest-posttest non-equivalent control and experimental groups. The subjects of this research were 62 gastrectomy patients hospitalized at Y medical center and the experimental and control groups consisted of 31 subjects. The experimental group received nursing intervention at the mutual goal setting of 5 times from the day before the surgery to the 5th day after the surgery, while the control group received only routine nursing care. Recovery indicators of both groups were measured and compared. Measurement variables included patients' characteristics, health locus of control, forced vital capacity, forced expiratory volume in one second, peak expiratory flow, bowel movement recovery, mobility recovery, level of pain, patients' stress and patients' satisfaction. Data were analyzed using SPSS statistical package and the hypotheses were tested by ANOVA and ANCOVA. Results of the analyses are summarized as follows : 1) Internal health locus of control had higher effects of the nursing intervention of mutual goal setting than external health locus of control on pulmonary ventilatory functions of forced vital capacity, forced expiratory volume in one second, and peak expiratory flow. 2) There was no statistically significant difference in the effects of nursing intervention of mutual goal setting on the bowel movement recovery between the internal and external health locus of control. 3) There was no statistically significant difference in the effects of nursing intervention of mutual goal setting on the mobility recovery between the internal and external health locus of control. 4) There was no statistically significant difference in the effects of nursing intervention of mutual goal setting on the level of pain between the internal and external health locus of control. 5) There was no statistically significant difference in the effects of nursing intervention of mutual goal setting on the level of stress between the internal and external health locus of control. 6) There was a statistically significant difference in the effects of nursing intervention of mutual goal setting on the level of satisfaction with provision of nursing information between the internal and external health locus of control, and there was no statistically significant difference in the effects of nursing intervention of mutual goal setting on the level of satisfaction with outcome of nursing between the internal and external locus of control. On the basis of the research results, the following are recommended : 1) Repeated research on responses to health locus of control is necessary. 2) Not only the effectiveness of nursing intervention in acute recovery periods, but also the long term effects are to be investigated. 3) The development of instruments is needed to accurately measure mutual goal setting regarding postoperative deep breath, coughing, early ambulation, etc. so that the relationship among the postoperative recovery indicators may be explored. 4) It is required that an instrument be developed to measure perception which facilitates goal attainment in the interactive setting between patients and nurses.

• 한국기계연구소 소보
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• s.19
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• pp.53-60
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• 1989

Hot upsetting experiments were carried out on presintered steel powder preforms in the temperature range 700- $950^{\circ}C$ to examine the hot deformation behavior. Following conclusions were drawn on the basis of the present study. -The flow stress during hot deformation is directly related to $\alpha$- $\gamma$ phase trasformation - The flow stress of ferrite is lower than that of austenite in the moderate temperature range 800- $900^{\circ}C$ for most alloys used in the present study - Major restoration behavior during hot deformation in the ferrite range is dynamic recovery.

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.329-330
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• 2003

In general, the thermoplastic elastomers have the elastic recovery property caused by phyical crosslinks after the stress is applied. Segmented block copolyetheresters also have been used as elastomers. Many$\^$l-2/ tried to improve the elastic recovery of those which are less elastic than polyurethane. We confirmed that the copolyetherester based on poly(2,6-butylene naphthalate)(PBN) ha.4 segment had the high melting temperature, whcih was useable at the broader temperature range and the one based on poly(1,3-trimethylene terephthalate)(PTT) the high crystallinity, which would be expected to get the high elastic recovery. (omitted)

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.251-255
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• 1997

The conventional high frequency phase-shifted full bridge dc/dc converter has a disadvantage that a circulating current flows through transformer and switching devices during the freewheeling interval. Due to this circulating current, RMS current stress, conduction losses of transformer and switching devices are increased. To alleviate this problem, this paper provides a circulating current free type high frequency soft switching phase-shifted full bridge (FB) dc/dc converter with energy recovery snubber (ERS) attached at the secondary side of transformer. The energy recovery snubber (ERS) adopted in this study is consisted of three fast recovery diode(Ds1, DS2, Ds3), two resonant capacitor (Cs1, Cs2)