• Journal of the Korean Geotechnical Society
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• v.30 no.7
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• pp.5-15
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• 2014

Abandoned mine deposits are exposed to various physico-chemical geo-environmental hazards and disasters, such as acid mine drainage, water contamination, erosion, and landslides. This paper presents the ring shear characteristics of waste materials. The ring shear box with a rotatable O-ring was used in this study. Three tests were performed: (i) Shear stress-time relationship for given normal stress and shear speed, (ii) shear stress as a function of shear speed, and (iii) shear stress as a function of normal stress. For a given normal stress (50 kPa) and speed (0.1 mm/sec), the materials tested exhibit a strain softening behavior, regardless of drainage condition. The peak and residual shear stresses were determined for each normal stress and shear speed. The shear stress was measured when shear speed is equal to 0.01, 0.1, 1, 10, 50, 100 mm/sec or when normal stress is equal to 20, 40, 60, 80, 100, 150 kPa. From the test results, we found that the shear stress increases with increasing shear speed. The shear stress also increases with increasing normal stress. However, different types of shearing mode were observed in drained and undrained conditions. Under drained condition, particle crushing was observed from the shearing zone to the bottom of lower ring. Under undrained condition, particle crushing was observed only at the shearing zone, which has approximately 1 cm thick. It means that a significant high shear speed under undrained condition can result in increased landslide hazard.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.1
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• pp.133-149
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• 1998

Clinical application of composite resin recently draw great concerns in dentistry. Especially due to advantages such as esthetics, adhesiveness, simple clinical procedures, various shapes and kinds of composite resins are widely being applied to prosthodontics, conservative dentistry, and orthodontics. But, clinical problems attributable to the polymerization shrinkage of composite resin have been proposed, and we have to regard clinical problems such as secondary caries, loss of restoration, fracture of the surrounding tooth structure, marginal discoloration, and tooth sensitivity, and many portions are remained to be overcome. Therefore, this study attempts to analyze stress distribution between resin and tooth structure which is generated during polymerization shrinkage of composite resin using three dimensional finite element method. Three dimensional finite element models with conventional box-shape cavity and erosion/abrasion type V-shape lesion cavity in upper central incisor were developed. These cavities were filled with four different types of placement techniques. (bulk filling, horizontal increment filling, oblique occlusal increment filling, oblique gingival increment filling) The stresses generated by polymerization shrinkage of composite resin were calculated. The results analyzed with three dimensional finite element method were as follows : 1. The increment filling technique showed the highest maximum normal stress in both conventional box-shape and V-shape cavities and showed a tendency to decrease after complete polymerization. 2. The bulk filling technique resulted in increased stresses during the curing process in both conventional box-shape and V-shape cavities and the highest maximum normal stress occurred after complete polymerization. 3. The bulk filling resulted in the lowest maximum normal stress in both box-shape and V-shape cavities 4. Regardless of placement method, in conventional box-shape cavity, the maximum normal stress increased in dentin floor, enamel, dentin sequence and in V-shape cavity, the maximum normal stress increased in enamel, dentin sequence.

• Journal of Korean Academy of Nursing
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• v.29 no.6
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• pp.1392-1402
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• 1999

This study was carried out to find out stress-eating relationship in obese high school girls and to investigate the factors related to stress-induced eating. The conceptual framework used in this study was individual difference model. The research method was methodological triangulation. The data of the study were collected from purposively sampled 309 normal high school girls and 314 obese high school girls in S city. 15 volunteers, obese high school girls, enrolled in this qualitative research. Quantitative data was collected from May 6 to June 10, 1997 through questionnaires about stress and stress-related eating changes and from June 23 to August 26, 1997, qualitative data was collected. The results of the study were as follows : 1. Obese high school girls were unaffected by stress(t=-1.84, p=0.0662). 2. Through quantitative analysis, obese people divided into two groups in their response to stress. One group was composed of stress- eater. The other group was composed of non- stress eater. 3. Disinhibition(t=-3.1275, p=0.0019), cognitive restrain (t=-3.1597, p=0.0017), hunger(t=-3.5878, p=0.0004) were significantly different between stress-eaters and non-stress eaters. 4. According to the interview, 5 subjects of obese girls were stress eaters, and 10 subjects were non-stress eaters. Through qualitative research, the related factors of eating were eating attitude & behavior, stimuli situations on eating, and personality. In stress-eater group, they constantly went on a diet, however, they were prompted to eat when an uneasy feeling such as anxiety, depression, annoyance developed. Their personality were entirely optimistic. Whereas non-stress eater group had no interest in diet and didn't appear to have psychological factors to stimulate eating in stressful situations. Their personality was not only optimistic but also keenly characteristic. 5. To compare obese-normal high school girls on the effect of stress in eating. Normal weigh high school girls decreased their eating when stressed(t= -13.62, p=0.0001). In conclusion, this study suggests that there are two different groups in obese high school girls in regards to eating responses on stressful situations. As a result of these finding, clinical and school nurses can detect the stress-eaters who need stress management intervention, and can apply appropriate management program according to the individual needs.

• Clinical and Experimental Reproductive Medicine
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• v.42 no.1
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• pp.1-7
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• 2015

Stress coping mechanisms are critical to minimize or overcome damage caused by ever changing environmental conditions. They are designed to promote cell survival. The unfolded protein response (UPR) pathway is mobilized in response to the accumulation of unfolded proteins, ultimately in order to regain endoplasmic reticulum (ER) homeostasis. Various elements of coping responses to ER stress including Perk, Ask1, Bip, Chop, Gadd34, Ire1, Atf4, Atf6, and Xbp1 have been identified and were found to be inducible in oocytes and preimplantation embryos, suggesting that, as a normal part of the cellular adaptive mechanism, these coping responses, including the UPR, play a pivotal role in the development of preimplantation embryos. As such, the UPR-associated molecules and pathways may become useful markers for the potential diagnosis of stress conditions for preimplantation embryos. After implantation, ER stress-induced coping responses become physiologically important for a normal decidual response, placentation, and early organogenesis. Attenuation of ER stress coping responses by tauroursodeoxycholate and salubrinal was effective for prevention of cell death of cultured embryos. Further elucidation of new and relevant ER stress coping responses in periimplantation embryos might contribute to a comprehensive understanding of the regulation of normal development of embryonic development and potentiation of embryonic development in vitro.

• Korean Journal of Rural Living Science
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• v.9 no.2
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• pp.19-31
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• 1998

The purpose of this study is to examine the levels of maternal stress, social supports and child-rearing attitudes of the mothers of handicapped children by comparing those mothers of normal children. The subjects were 100 mothers of mentally handicapped children from elementary schools for handicapped children as well as 100 mothers of normal children from elementary schools in Pusan. The results are as follows : 1) The mothers of handicapped children showed significantly higher in maternal stress than the mothers of normal children. 2) For social support, the mothers of handicapped children recognized that they received significantly more insociable and emotional support than the mothers of normal children, but not in economic and service support. 3) For child-rearing attitudes, the mothers of handicapped children shelved significantly lower in lax attitude but not significantly different in affective, strict. punitive attitude than those of normal children. 4) For the mothers of handicapped children, they tend to be more affective and lax in child-rearing attitude when they receive more social support, while they tend to be more punitive when they have less sociable support.

• Journal of Oriental Neuropsychiatry
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• v.9 no.2
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• pp.87-95
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• 1998

This study was aimed to evaluate the anti-stress effect of Soeuminsohabhyangwon on the mice in Cold and Swimming stress.In order to investigate the anti-stress effect of Soeuminsohabhyangwon in Cold and Swimming stressed mice, the serotonin contents were measured by HPLC method in various part of mouse brain The following results were observed. 1. In Cerebral Cortex of Frontal Lobe, the serotonin content was decreased in the Control group as compared with Normal group and the serotonin content was increased in the SHW group as compared with Control group. 2. In hypothalamus, the serotonin content was decreased in the Control group as compared with Normal group and the serotonin content was increased with statistical significance in the SHW group as compared with Control group. 3. In corpus striatum, the serotonin content was decreased in the Control group as compared with Normal group and the serotonin content was increased with statistical significance in the SHW group as compared with Control group. 4. In hippocampus, the serotonin content was decreased in the Control group as compared with Normal group and the serotonin content was increased with statistical significance in the SHW group as compared with control group.Base on the above results, it may be concluded that Soeuminsohabhyangwon are effective to reduce stress.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.1 s.190
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• pp.118-125
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• 2007

In this study, we analyzed the plantar shear stress and normal pressure in lateral heel diabetic foot patients during walking by using in-shoe local shear stress and plantar pressure measurement systems. The shear force transducer based on the magnetic-resistive principle, was a rigid 3-layer circular disc. Shear transducers were mounted on the locations of four metatarsal heads and heel in the insole. Twelve normal subjects and three diabetic foot patients with diabetic neuropathy in the lateral heel participated in this study. The center of pressure in lateral heel diabetic foot patients moved more medially and directed toward the first, medial to the second metatarsal heads, and the hallux during late stance, making pressure at the medial heel and the second metatarsal head significantly larger than in the normal. Shear stress at the heel changed significantly in early stance and the magnitude of shear stresses in each metatarsal head also changed. Further studies would be very helpful to design foot orthoses in patients with diabetic neuropathy or other diseases.

• Nuclear Engineering and Technology
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• v.55 no.1
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• pp.80-99
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• 2023

This paper presents the results of investigating the change in welding residual stresses of the core shroud, which is one of subcomponents in reactor vessel internals, performing finite element analysis. First, the welding residual stresses of the core shroud were calculated by applying the heat conduction based lumped pass technique and finite element elastic-plastic stress analysis. Second, the temperature distribution of the core shroud during the normal operation was calculated by performing finite element temperature analysis considering gamma heating. Third, through the finite element viscoelastic-plastic stress analysis using the calculated temperature distribution and setting the calculated residual stresses as the initial stress state, the variation of the welding residual stresses was derived according to repeating the normal operation. In the viscoelastic-plastic stress analysis, the effects of neutron irradiation on mechanical properties during the cyclic normal operations were considered by using the previously developed user subroutines for the irradiation agings such as irradiation hardening/embrittlement, irradiation-induced creep, and void swelling. Finally, the effect of neutron irradiation on the welding residual stresses was analysed for each irradiation aging. As a result, it is found that as the normal operation is repeated, the welding residual stresses decrease and show insignificant magnitudes after the 10^th refueling cycle. In addition, the irradiation-induced creep/void swelling has significant mitigation effect on the residual stresses whereas the irradiation hardening/embrittlement has no effect on those.

• Advances in concrete construction
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• v.9 no.1
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• pp.43-54
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• 2020

This paper presents an innovative stress-function variational approach in formulating the interfacial shear and normal stresses in an externally bonded concrete joint using carbon fiber-reinforced plastic (CFRP) plies. The joint is subjected to surface traction loadings applied at both ends of the concrete substrate layer. By introducing two interfacial shear and normal stress functions on the CFRP-concrete interface, based on Euler-Bernoulli beam idea and static stress equations of equilibrium, the entire stress fields of the joint were determined. The complementary strain energy was minimized in order to solve the governing equation of the joint. This yields an ordinary differential equation from which the interfacial normal and shear stresses were proposed explicitly, satisfying all the multiple traction boundary conditions. Lamination theory for composite materials was also employed to obtain the interfacial stresses. The proposed approach was validated by the analytic models in the literature as well as through a comprehensive computational code generated by the authors. Furthermore, a numerical verification was carried out via the finite element software ABAQUS. In the end, a scaling analysis was conducted to analyze the interfacial stress field dependence of the joint upon effective issues using the devised code.

• Journal of the Korean Institute of Landscape Architecture
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• v.28 no.6
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• pp.106-113
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• 2001

The purpose of this study is to find out the effect of recovery from psychological stress when watching plants indoors. As an instrument of measurement of psychological stress, Galvanic Skin Resistance(GSR) has been used because it has been convenient to read a psychological sign without a medical sense and an instrument. In order to make the conditions of stress and recovery, video programs have been made, and especially, the video program of recovery has consisted of three types-- types 1 of watching plants in a botanical garden, type 2 of watching very bush street, and type 3 of closing eyes naturally. The two groups of normal and the mentally handicapped persons have been participated in this experiment to compare the effect of recovery. As the result of this test, the rate of stress relief has been maximumly effected by watching the video program of plants. Between the two groups the recovery of stress has had better effects on the mentally handicapped than the normal one. And also it shows that the circumstances of emotional refinement is led by having plants in indoor. The result of this test has been turned out to be highly useful. It is desirable that a indoor worker, staying for a long time, contact with plants visually to keep healthy mental conditions. This study suggests that the surrounding conditions or the settings of circumstances play an important role for the emotional refinement of the groups of mentally han야capped persons as well as the normal person.