• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 봄 학술발표회 논문집(I)
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• pp.339-345
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• 1998

The creep of concrete structures caused by variable stresses is mostly calculated by step-by-step method based on the superposition of creep function. Although most practical application is carried out by this linear assumption, significant deviations between predictions and experiments have been observed when unloading takes place, that is, stress is reduced. The recovery is overestimated. The main purpose of this study is to present the application method of the creep analysis model which is expressed with both creep function and creep recovery function to concrete structures where is expressed with both creep function and creep recovery function to concrete structures where increase or decrease of stress is repeated . To apply two function method to time analysis of concrete structures, this study presents the calculation method of creep strain increment for stress variation. Then, this paper executes the time analysis for an example using suggested method, and compares theses results with the previous analysis values and experimental results.

• 한국산학기술학회논문지
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• 제19권11호
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• pp.662-671
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• 2018

본 연구는 중소병원 간호사의 스트레스 대처능력, 회복탄력성과 재직의도와의 관계를 알아보고 재직의도에 미치는 영향요인을 파악하기 위한 서술적 조사연구이다. 조사대상은 G지역과 I시에 위치한 150병상 이상의 5개 중소병원 간호사 265명을 대상으로 하였으며, 자료 수집은 2018년 5월 19일부터 5월 25일까지 시행하였다. 수집된 자료는 IBM SPSS/WIN 23을 이용하여 t-test, ANOVA, Pearson 상관관계와 다중회귀분석을 시행하였다. 연구결과, 대상자의 스트레스 대처능력은 4점 만점에 $2.55{\pm}0.25$점, 회복탄력성과 재직의도는 5점 만점에 각각 $3.47{\pm}0.49$, $2.59{\pm}0.29$점이었다. 또한 재직의도는 스트레스 대처능력(r=.285, p<.01)과 회복탄력성(r=.457, p<.01)에 양의 상관관계가 있었다. 중소병원 간호사의 재직의도에 영향을 미치는 요인은 성별(${\beta}=.117$, p=.027), 간호직 만족도(${\beta}=.345$, p<.001), 스트레스 대처능력(${\beta}=.142$, p=.008), 회복탄력성(${\beta}=.238$, p<.001)이었으며, 재직의도에 대한 설명력은 37.8%였다(F=11.686, p<.001). 따라서 중소병원 간호사의 재직의도를 향상시키기 위해서 간호만족도, 스트레스 대처능력과 회복탄력성을 높일 수 있는 중재방안이 모색되어야 함을 확인할 수 있었다. 중소병원 내 간호만족도와 유대감을 높이기 위한 노력, 개인의 스트레스 관리를 위한 체계적인 프로그램을 통해 간호의 질 향상에 기여할 수 있을 것으로 본다.

• 대한기계학회논문집
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• 제10권3호
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• pp.292-297
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• 1986

본 연구에서는 2024 Al 합금에 대하여 260-380.deg. C의 온도 범위 및 2~5kgf/ m $m^{2}$의 부과응력 범위에서 실시한 고온 정상 크리이프 변형 중의 내부응력 .sigma. $_{i}$,의탄성 변형 .epsilon.$_{A}$ 및 회복율 r의 측정 실험을 통하여 이들 상호간의 관계 를 살펴 보고자 한다.다.다.

• Journal of Biosystems Engineering
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• 제14권3호
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• pp.181-187
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• 1989

The mechanical and rheological properties of agricultural materials which influence the machine design or handling are not completely understood. Agricultural materials do not react in a purely elastic manner, and their responses when subjected to stress and strain appear a combination of elastic and viscous behavior. Many researchers have studied the mechanical and rheological properties of the various agricultural materials, but those properties are available mostly for foreign varieties of agricultural products. Rheological properties of rice seedlings become important to formulate the principles governing their mechanical behavior. The objectives of this study were to experimentally determine the creep and recovery behavior of rice seedlings of one japonica-type and one Indica x japonica hybrid in the transplanting age. The results of this study are summarized as follows; 1. The compression creep and recovery behavior of mat-type seedlings could be described by 4-element Burger's model. 2. The steady-state creep appeared at the stress larger than 0.8 MPa and the logarithmic creep appeared at the stress smaller than 0.8 MPa. 3. In the compression creep test of the rice seedlings, the instantaneous elastic modulus of Burger's model showed the range from 20 to 40 MPa. The higher value of absolute viscosity for the rice seedling explained that the rice seedlings were viscoelastic materials. 4. In the recovery test of the rice seedlings, there was a tendency that the higher permanent strain of all samples was observed under the smaller stress being appeared, and the larger permanent strain in Dongjin was observed than in Samkang.

• The Korean Journal of Pain
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• 제10권1호
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• pp.113-116
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• 1997

Sensorineural hearing loss(SNHL) is defined as a sudden hearing impairment which was develope over a period of hours to days. The definitive cause of SNHL is unknown in most cases. Disturbance of the blood flow of the inner ear is a main causal hypotheses. Most symptomatic treatment is focusing to improving the blood flow of the inner ear. At our hospital, most patients are recommended to bed rest, vasodilators(nicotinic acid, antihistamines) and stellate ganglion block(SGB) for two weeks. We experienced two cases of recurrence immediately after recovery from SNHL. They discontinued SGB after initial recovery. due to associated pain with operation and or psychologic stress. One patient resumed SGB and medication treatment, but the second who gave up treatment was not recovered. Therefore, we recommend to continuance of treatment of stellate ganglion blocks to improve recovery rate of SNHL and avoid further trauma and psychologic stress during the recovery period of SNHL.

• 한국직업건강간호학회지
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• 제26권3호
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• pp.172-183
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• 2017

Purpose: This study was conducted to investigate factors affecting the job embeddedness of workers in the manufacturing industry. Methods: The survey was conducted on 261 workers of the manufacturing industry in P city and Y city with the help of a structured self-report questionnaire, administered between June 10 and June 30, 2017. Data were analyzed using descriptive statistics, a t-test, ANOVA, a $Scheff{\acute{e}}s$ test, Pearson's correlation coefficients, and stepwise multiple regression. Results: There were significant differences in job embeddedness according to educational level, marital status, jobs and types of employment, satisfaction with salary, stress level, and the perceived health status of the subjects. There were significant positive correlations between role clarity of job demands (r=.45), leader member exchange (r=.48), recovery experience from job stress (r=.27), and job embeddedness. From the multiple regression analysis, the most significant factors affecting job embeddedness were found to be leader member exchange (${\beta}=.43$), recovery experience from job stress (${\beta}=.22$), and job demand (${\beta}=.15$). These variables explained 35.0% of the total variance in job embeddedness. Conclusion: In order to increase job embeddedness of workers in the manufacturing industry, it is necessary to prepare measures to increase job demand, leader member exchange, and recovery experience from job stress.

• 대한간호학회지
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• 제4권2호
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• pp.44-56
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• 1974

Very few studies regarding the effects of preoperative nursing intervention on children's welfare after surgery have been conducted. The purpose of this study was 1) to evaluate the effects of preoperative nursing instructions on children's physical recovery and emotional state after surgery and 2) to analyse the relationship between the effects of preoperative nursing instructions and the age and general anxiety of child. The study was conducted flow: August 15th to October 30th at Severance Hospital, Seoul, Korea. A total of 41 Pediatric surgical Patients, between the age of 4 to 14, participated in the study. Twenty patients, randomly selected, were visited by the experimenter in the evening before, surgery and received specific preoperative nursing instructions. These instructions were designed to alleviate emotional stress and were adopted to the age of child. The postoperative recovery of these patients were then compared with a randomly selected control group of 21 patients who received only the routine preoperative care by the staff in the hospital Dependent variable were vomiting, pain medication, ability to void, elevation of temperature, infection, the between surgery and hospital discharge and postoperative emotional stress which was measured by the vital signs. Because of the limitation of the sample size it was difficult to obtain valid statistical results. However, the analysis of the raw data indicates that: 1) the preoperative nursing instructions appears to promote physical recovery and it seems especially effective in preventing elevation of temperature and shortening the length of the hospital stay, 2) the preoperative nursing instruction also seems to be effective in relieving the child's emotional stress(situational anxiety) after surgery, 3) the patient's general anxiety level preparatively seems to be a predictor of postoperative problems, 4) the preoperative nursing instructions were an effective means of promoting physical recovery in every age group as long as the child understood the instructions. The above data would seem to indicate that all preoperative pediatric patients four years of age or older, if they can understand, should have preoperative nursing instruction in order to alleviate postoperative stress and enhance physical recovery. The level of general anxiety preparatively deserves special attention since the amount of nursing instruction needed seems to vary with tile level of anxiety.

• 대한한의학회지
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• 제30권1호
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• pp.83-94
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• 2009

Background and Objectives: The skin barrier protects skin against a harmful environment. Its function includes an antimicrobial barrier as well as a physical barrier. Stress is harmful to the skin barrier and there are many studies on this, but there are few about the effect of stress during pregnancy on the skin barrier of offspring. The aim of this study was to investigate the effect of stress during pregnancy on the skin barrier of offspring by examination with the naked eye, cortisol, weight, TEWL and histologic tests. Materials and Methods: Male hairless mice ten weeks old were coupled with females for three days. After twelve days the females were divided into two groups. We stressed one group and not the other group. The offspring from the non-stressed (N group) and stressed (S group) grew up until four weeks. The S group was exposed to chronic mild stress using the chronic stress model protocol modified method of Wilner and Towell for a week. We made examinations with the naked eye, assessment of cortisol, weight, TEWL, and histologic test to contrast the S group with the N group. Statistical analysis was performed by using Mann-Whitney and Friedman test. Statistical significance was achieved if the probability was less than 5% (p<0.05). Results: 1. By making an examination with the naked eye, S group showed papules, creases and dryness on their skin, but N showed no change compared with normal skin. 2. There was no statistically significant difference between S group and N group in cortisol (p>0.05). 3. There was no statistically significant difference between S group and N group in weight. N group had less weight than S group (p<0.05). 4. There was no statistically significant difference between S group and N group in TEWL (p>0.05). 5. There was no statistically significant difference between S group and N group in TEWL recovery (p>0.05). 6. In TEWL and TEWL recovery, there was statistically significant difference by time between S group and N group (p<0.005). Histologically, S group showed a thicker epidermis and epidermal crest than N group. Conclusions: We found that stress during pregnancy has negative effects on the skin barrier of offspring. Though there were no statistically significant differences between S group and N group in TEWL recovery, we found evidence that the recovery of skin barrier function is interrupted by stress during pregnancy by examination with both the naked eye and histology.

• Journal of Biosystems Engineering
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• 제16권1호
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• pp.37-48
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• 1991

Rice plants are subjected to various forces such as natural force of wind and mechanical force of cultivating machines. Rheological behavior of the rice stem can be expressed in terms of three variables : stress, relaxation and time. The objectives of this study are to examine stress relaxation, creep and recovery characteristics on the rice stem in case of axial and radial loading. Stress relaxation with time was studied on three levels of loading rate and on four levels of applied stress. The results were summarized as follows : 1. The hysterisis losses of the rice stem distinctly observed at the radial compression in comparison with axial compression. The hysterisis loss implied that the stem to absorbed energy without being deformed beyond the yield point. 2. Ageneralized Maxwell model consisting of three elements gave a good description of the relaxation behavior of the rice stem. Rate of loading was more significant on the observed relaxation behavior within the short relaxation time, but there were little influences of rate of loading on the relaxation time. 3. The stress relaxation intensity and the residual stress increased in magnitude as the applied stress increased, but the relaxation time was little affected by the applied stress. 4. The coefficients of the stress relaxation model showed much differences in the radial compression and the axial compression, especially the higher relaxation stress of the third element was observed in the radial compression. 5. The behaviors of rice stem in creep and recovery test also might be represented by a four element Burger's model. But the coefficients of the creep model were different from those of the recovery model. 6. The steady-state phenomena of creep appeared at the stress larger than 20 MPa in Samkang and 1.8 MPa in Whajin. 7. The elastic modulus of the stem showed the range from 40 to 60 MPa. It could be considered, as a result, the rice stems had viscoelastic properties.

• 인간식물환경학회지
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• 제23권3호
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• pp.363-375
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• 2020

Background and objective: Recreation or activities in forest are regarded as therapy. Many forest therapy programs have been developed and assessed in the domestic. This study was conducted to investigate the effect of the forest therapy program on academic and job-seeking stress in college students. Methods: Thirty five subjects were selected as the experimental group and 25 as the control group, and 29 subjects in the experimental group and 11 in the control group participated in the follow-up test to verify the persistence of stress reduction effects. The forest therapy program was carried out once a week for 2 hours each from September 4 to December 4, 2018, adding up to total eight sessions. Results: The experimental group showed statistically significant reduction in both academic stress and job-seeking stress, whereas the control group did not. For the persistence of the forest therapy program, the experimental group did not show a statistically significant difference between the posttest and the follow-up test, and thus the stress reduction effect was maintained. Conclusion: This study proved the reduction of academic and job-seeking stress in forest therapy programs and the persistence of the stress reduction effect of the forest therapy program. The result is consistent with the Stress Recovery Theory (SRT) that shows the stress reduction effect of nature. In addition, it has significance in that it has verified that the program using the forest on campus can reduce stress of most college students.