• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1996년도 봄 학술발표회 논문집
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• pp.264-269
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• 1996

Thermal cracks are occurred when thermal stress due to the hydration of cement exceeds the tensile strength of concrete. In this study, the thermal stresses are investigated at the massive concrete like an anchorage of suspension bridge. The thermal crack can be controlled by considering the placing height, concrete type, pre-cooling and pipe cooling in the design stage.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1991년도 가을 학술발표회 논문집
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• pp.124-128
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• 1991

Wood, laminates, reinforced concrete, and some special types of metals systems with controlled grain orientation are often orthotropic and at least rectilinearly anisotropic from point to point, if regarded as homogeneous media. Orthotropic bodies where a crack is not associated with a plane of elastic symmetry may be conveniently treated as a crack problem in a generally anisotropic body. At this work, approach for the determination of the stress intensity factors (SIF) of anisotropic body using crack tip singular elements is presented. Caculated values are in good agreement with the others.

• 대한간호학회지
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• 제35권6호
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• pp.1183-1189
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• 2005

Objectives : This descriptive study was conducted to examine the degree of stress, coping styles, communication with the mother and depression between headache-suffering children and headache-free children and to explore predicted factors for headache occurrence in children. Method : The subjects of this study consisted of 196 headache-free children and 107 headache-suffering children. They were 4th-6th graders of an elementary school in T city. The instruments in this study were David's stressor of children, Lazarus & Folkman's Stress Coping Style, PACI(Parent-Adolescent Communication Inventory) by Barnes & Olsen and Kovac's CDI (Children's depression inventory). Data were collected from May 2 to July 16, 2004. Results : Total stress(t=-3.76, p=.035), school stress(t=-3.02, p=.001), mass media stress(t=-1.39, p=.029) and depression(t=7.62, p=.001) in headache-suffering children were significantly higher than those of headache-free children. Problem-oriented coping skills (t=1.23, p=.023), and the score of communication with the mother(t=2.32, p=.012) in headache-suffering children were lower than those of headache-free children. Logistic regression analysis (stepwise) showed that the most powerful predictor was stressors in school, followed by depression, stressors in mass media and communication with the mother. Conclusions: This study revealed that important factors such as the degree of school stress, depression, the degree of mass media stress, communication with the mother and problem-oriented coping skills should be controlled for reducing of headaches in children.

• 수산해양교육연구
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• 제29권3호
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• pp.732-745
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• 2017

The purpose of this study was to analyze the influence of collective self-esteem on teachers' job stress. For the study, 223 teachers in elementary school, junior high school, and high school were selected and data on teachers' background variables, collective self-esteem, and job stress were collected. The relationship between variables was analysed by using multiple regression analysis. The results were as follows: The job stress of teacher was significantly different according to teacher's gender, school level, and career experience. When the influence of background variables was controlled and multiple regression analysis was performed, the group self-esteem of teachers had a great influence on mitigating the perception of job stress. Particularly, it was shown that private collective self-esteem and importance to identity are the most important factors in mitigating job stress perception among the sub-variables of collective self-esteem. These results showed that it is an important task for our society to find an effective way to elevate the teacher's collective self-esteem. Teachers' collective self-esteem is expected to play a positive role not only in mitigating job stress but also in enhancing self-fulfillment and personal self-esteem of teacher.

• 동력기계공학회지
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• 제10권3호
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• pp.45-50
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• 2006

In this paper, creep tests of Mg-Zn-Mn and Mg-Zn-Mn-Ca alloy casted by mold under the temperature range of 473.00-573.00K, and the stress range of 23.42-87.00Mpa were done with the equipment of automatic controlled temperature and computer for data acquisition. The activation energies were obtained by relationship between creep rate and temperature, and the stress exponents were obtained by relationship between creep rate and stress. From the experiment results, the activation energies of Mg-Zn-Mn and Mg-Zn-Mn-Ca alloy were 149.87kJ/mol, 147.97kJ/mol, respectively, and the stress exponents of those alloy were 5.13, 5.59, respectively, under the temperature of 473.00-493.00K and the stress range of 62.43-78.00Mpa. And the activation energies of those alloy were 134.41kJ/mol, 129.22kJ/mol, respectively, and the stress exponent of those alloy were 3.48, 3.77, respectively, under the temperature of 553-573Mpa and the stress range of 23.42-39.00Mpa. Also the lifes of Mg-Zn-Mn-Ca alloy were higher than those of Mg-Zn-Mn alloy, and the results of SEM showed fracture surfaces under low temperature had smaller dimples than those under high temperature.

• 가정과삶의질연구
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• 제28권5호
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• pp.67-74
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• 2010

This study investigates the effects of adult attachment on parenting stress using marital conflict as a mediating variable for mothers of preschoolers. The subjects were 370 mothers who lived with at least one preschooler in Daegu or Gyeongbuk Province. The collected data were analyzed by Pearson's correlation as well as single and multiple regressions that used SPSS Win 15.0. The results were as follows: (1) The adult attachment by mothers was negatively associated with parenting stress. The adult attachment level of mothers becomes lower as the perception of parenting stress increases. (2) The adult attachment by mothers was negatively associated with marital conflict. That is, the adult attachment level of mothers becomes lower as the perception of marital conflict increases. (3) The effects of adult attachment in parenting stress by mothers was reducing explanation when controlled for the marital conflict. Adult attachment which influenced the parenting stress of mothers was partially mediated by marital conflict. The results of the study imply that to reduce the parenting stress of mothers, there is a need to improve spousal relationships, in addition, there is a need for more active support to improve conjugal relations for mothers whose adult attachment was not stable.

• Animal Bioscience
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• 제37권6호
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• pp.1121-1129
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• 2024

Objective: Objective of the study was to reduce heat stress in Murrah buffaloes and maintain their milk production and other vital functions during heat stress. Methods: A total of 21 dyads of calf-mother Murrah buffalo were selected for the study and equally divided in 3 treatment groups. First treatment group was restricted calf contact (RCC), second treatment group was fence line calf contact (FCC) and third treatment groups fence line calf contact and heat stress protection (FCC-HSP [time-controlled fan-fogger system] in the shed). Present study was conducted from April to mid-September 2021. Results: Maximum temperature and temperature humidity index in FCC-HSP shed were significantly (p<0.05) lower than that in FCC and RCC shed. Higher (p<0.05) mean daily milk yield in both the treatment groups FCC (10.36±0.30) and FCC-HSP (10.97±0.31) than RCC (8.29±0.41) was recorded. Though no significant difference between FCC and FCC-HSP in daily milk yield but FCC-HSP yielded 600 gm more milk than FCC. Pulse rate (PR) and respiration rate (RR) were lowest in FCC-HSP followed by FCC and RCC, respectively. Cortisol and prolactin levels were lower (p<0.05) in FCC-HSP followed by FCC and RCC, respectively. Conclusion: Hence, FCC along with heat stress ameliorative measures helped the buffaloes to be free of stress and maintain milk yield during heat stress period of the year in tropical conditions.

• 소성∙가공
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• 제15권8호
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• pp.603-608
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• 2006

The main purpose of the present study has been placed on investigating the mechanical properties and microstructures of C-Si-Mn-V steels for cold forming manufactured by controlled rolling and cooling technology. The steels were manufactured in electric arc furnace (EAF) and casted to $160{\times}160mm$ billet. The billets were reheated in walking beam furnace and rolled to coil, the stocks were rolled by Controlled Rolling and Cooling Technology (CRCT), so rolled at low temperature by water spraying applied in rolling stage and acceleratly cooled before coiling. Rolled coils were cold drawed to the degree of 16%, 27% of area reduction respectively without heat treatment. Microstructual observation, tensile test, compression test and charpy impact tests were conducted. The mechanical properties of the steels were changed by area reduction of cold drawing and it is founded that there are optimum level of cold drawing to minimize compression stress for these steels. From the result of this study, it is conformed that $80kg_{f}/mm^{2},\;90kg_{f}/mm^{2}$ grade high strength microalloyed steel for cold forming are developed by accelerated cooling and optimum cold drawing.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 춘계학술대회 논문집
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• pp.321-324
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• 2005

The main purpose of the present study has been placed on investigating the effects of controlled rolling and cooling on the microstructures and mechanical properties of C-Si-Mn-V steels for cold forming. The steels were manufactured in vacuum induction melting(VIM) furnace and casted to 1.1ton Ingots and the ingots were forged to $\Box150$ billet. The forged billets were reheated in walking beam furnace and rolled to coil, the stocks were rolled by Controlled Rolling and Cooling Technology (CRCT), so rolled at low temperature by water spraying applied in rolling stage and acceleratly cooled before coiling. Rolled coils were cold drawed to the degree of $27\%$ of area reduction without heat treatment. Microstructual observation, tensile test, compression test and charpy impact tests were conducted. The mechanical properties of the steels were changed by area reduction of cold drawing and it is founded that there are optimum level of cold drawing to minimize compression stress for these steels. From the result of this study, it is conformed that mechanical properties and microstructure of C-Si-Mn-V steels for cold forming were enhanced by accelerated cooling and founded optimum level of cold drawing.

• 대한간호학회지
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• 제35권8호
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• pp.1485-1492
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• 2005

Purpose. The present study aims to verify the effectiveness of the reality therapy for patients with schizophrenia. Methods. It is designed as a quasi-experimental study by which a nonequivalent control group pretest-posttest is conducted. The test was conducted with 30 patients with schizophrenia who were hospitalized at a mental hospital in South Korea. Fifteen of the patients participated in the reality therapy program while another 15 in the control group. The effects are measured by marking scores in the areas of the locus of control, self-esteem, and problem-focused stress coping of each participant. Results. The general characteristics and dependent variables related to outcome variables were controlled to be equal between the two groups. It turns out that the internal locus of control, self-esteem, and problem-focused stress coping are statistically significant. Conclusion. Findings show that the reality therapy caused positive changes in terms of the internal locus of control, self-esteem, and problem-focused stress coping of the observed schizophrenic patients.