• 동의신경정신과학회지
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• 제25권2호
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• pp.191-202
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• 2014

Objectives: The purpose of this study was to examine the anti-depressive effects of BanHaHuBakTang-kami (BHHBT) on an animal model of depression induced by chronic immobility stress. Methods: Mice were treated daily with immobilization stress for 2 hours over a period of 21 days. To examine the effect of BHHBT, we performed behavioral, biochemical and histological analysis to measure immobility time (FST), brain neurotransmitter concentration (HPLC, ELISA), hippocampal damage (H&E staining) and CRF-R1 expression (immunohistochemistry). Results: BHHBT has reduced the immobility time of immobilization stress exposed mice in the forced swimming test. BHHBT has increased the amount of serotonin in the brain. BHHBT has increased the expression level of serotonin in the brain. BHHBT 540 mg/kg were sufficient to prevent tissue damage in the hippocampus region. BHHBT has reduced the expression level of CRF receptors in the hippocampus region. Conclusions: These results suggest that BHHBT may have anti-depressive effects on mice treated with immobilization stress by reducing immobility, increasing brain serotonin concentration and reducing CRF-R1 expression in the hippocampus region.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2004년도 춘계학술발표회
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• pp.227-234
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• 2004

Sand compaction pile (SCP) method is composed of compacted sand pile inserted into the soft clay deposit by displacement method. SCP-reinforced ground is composite soil which consists of the SCP and the surrounding soft soil. When a surcharge load is applied on composite ground, time-dependent behavior occurs in the soft soil due to consolidation according to radial flow toward SCP and stress transfer also takes place between the SCP and the soft soil. This paper presents the numerical results of cylindrical composite ground that was conducted to investigate consolidation characteristics and the stress transfer mechanism of SCP-reinforced composite ground. The results show that the consolidation of soft clay has a significant effect on the stress transfer mechanism and stress concentration ratio of composite ground

• 한국재료학회지
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• 제15권9호
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• pp.560-565
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• 2005

The objective of this paper is to decide optimal of the slot angle to minimize stress concentration in rotating disc of diamond saw. The fracture phenomena of the slot are discussed by the theoretical and experimental approaches and then some recommendation are presented to prevent the fracture. The focus of this investigation is to evaluation the effect of the slot on stress distribution using optimum design technique and finite element method(FEM) analysis. Stress concentration of the slot with respect to the various parameter of the slot such position, size, number, rotation speed. From the experimental results, when the slot angle of diamond saw is located $8^{\circ}\~12^{\circ}$ from rotating direction, the maximum equivalent stress reduces.

• 대한치과보철학회지
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• 제33권3호
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• pp.517-538
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• 1995

Dental implantation is a method restoring missing teeth, especially in the case of severely resorbed edentulous patient. But the direct contact between bone and implant surface, induces stress concentration to the bone and eventually becomes a cause. The purpose of this study was to compare the stress distribution patterns between following two cylindrical implant models. One group has implant apex located in the inferior cortical bone and the other in the cancellous bone. Anterior edentulous mandible was modeled with two dimensional 953,878 nodes, 995,918 elements and compared the deflection and stress distribution under the 70 N,4 load cases for 26 models having variant mandibular height and length. The result were as follows; 1. The stress concentration was more affected by the height of the mandible than implant length. 2. Bicortication mitigates the stress of upper cortical and cancellous bone area at the same height of the mandible 3. Perforation of the inferior mandibular cortex significant stress concentration. 4. Stud type porstheses induced less stress concentration to the cortical and cancellous bone than bar type prostheses. 5. Stress of implant apex for stud type was larger than that of bar type.

• 한국식품조리과학회지
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• 제5권1호
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• pp.9-13
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• 1989

초산용액의 초산농도를 0, 1, 2, 4, 6%로 변화하여 제조한 마요네즈의 유동 특성, 유화 안정성, 색도에 대하여 조사하였다. 마요네즈의 유동은 항복응력을 가지는 소성유동이며, 초산농도가 높아질수록 항복응력 및 점주도지수가 커져서 초산농도가 높아질수록 마요네즈의 물성이 점주해지는 것을 나타내었다. 마요네즈의 유화안정성은 초산농도가 높아질수록 감소하는 경향을 보였고, 초산노도 4%일 때 가장 안정성이 낮았다. 색도는 초산함량이 증가할수록 L값(명도)이 증가하고 b값(yellowness)은 감소하였다.

• 대한치과보철학회지
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• 제38권3호
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• pp.348-357
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• 2000

The purpose of this study is to examine the effect of partial osseointegration situation on bone loading patterns around two different free-standing screw shaped implants (Nobel Biocare, Gothenburg, Sweden and Degussa-Huls, Hanau, German). Two dimensional axisymmetric Finite element models of two implants(10mm length and 4mm diameter) were created according to different bone quantity, quality and osseointegration ratio in maxilla and mandible bone. At the same time uni-cortical and hi-cortical fixation were analyzed. Generally, full bond case showed less stress than partial bond case in overall area and mandibular model showed less amount of stress than that of maxilla model. Maximum stress of the Branemark implant is higher than that of ANKYLOS regardless of bonding ratio at crestal and apex region. However, more stress concentration was noted in ANKYLOS implant at screw body area especially in mandible. The effect of bicortical fixation on crestal bone stress reduction is dramatical in mandible however, there was no significant effect in maxillary case. The effect of partial bond on stress distribution was more significant at screw body and apex region than in crestal region. Partial bond cases demonstrated greater stress accumulation in trabecular bone than cortical bone. It is concluded that the more accurate model of implant and bone which affects stress and strain distribution is needed to mimic in vivo behavior of implants.

• 산업기술연구
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• 제20권A호
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• pp.169-178
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• 2000

The 4-point bending tests have been performed In order to estimate the effect of TIG-dressing on fatigue strength and fatigue characteristics quantitatively for non load-carrying fillet welded joints subjected to pure bending. As a result of fatigue tests, fatigue strengths of as-welded specimens have satisfied the grade of fatigue strength prescribed in specifications of korea, AASHTO and JSSC. Fatigue strength at 2 million cycles of TIG-dressing specimens have increased compared with as-welded specimens. As the result of beachmark tests, fatigue cracks occurred at several points, where the radius of curvature and flank angle in the weld bead toes were low, and grew as semi-elliptical cracks, then approached to fracture. As a result of finite element analysis, stress concentration factor in weld bead toes has closely related to the flank angle and radius of curvature, and between these, the radius of curvature has more largely affected in stress concentration factor than flank angle. As a result of fracture mechanics approaches, the crack correction factor of test specimens has largely affected on stress gradient correction factor in case a/t is below 0.4. From the relations between stress intensity factor range estimated from FEM analysis and fatigue crack growth rate, fatigue life has been correctly calculated.

• 한국정밀공학회지
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• 제21권6호
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• pp.131-138
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• 2004

The objective of this paper is to decide optimal location of a pin-hole to minimize stress concentration around the hole in a rotating disc. The focus of this investigation is to evaluate the effect of pin-hole on stress distribution around the hole using optimum design technique and finite element analysis. Design variables are the radial and the angular location of pin-hole from center of the hole and objective function is the maximum stress around hole in a rotating disc. Using first order method of optimization technique, we found that the maximum equivalent stress around the hole with optimized pin-hole could be reduced by 15.1% compared to that without pin-hole.

• Steel and Composite Structures
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• 제34권2호
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• pp.309-319
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• 2020

The objective is to study the deformation in a homogeneous isotropic modified couple stress thermoelastic medium with mass diffusion and with two temperatures due to a thermal source and mechanical force. Laplace and Fourier transform techniques are applied to obtain the solutions of the governing equations. The displacements, stress components, conductive temperature, mass concentration and couple stress are obtained in the transformed domain. Numerical inversion technique has been used to obtain the solutions in the physical domain. Isothermal boundary and insulated boundaryconditions are used to investigate the problem. Some special cases of interest are also deduced.

• Nutritional Sciences
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• 제6권2호
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• pp.67-72
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• 2003

This study was conducted to investigate the effect of oligosaccharide on the reduction of oxidative stress. Sprague-Dawley rats were fed an AIN-93G diet or a diet containing 5% soybean oligosaccharide for 6 weeks. Each group was divided into two sub-groups after streptozotocin (STZ) injection and fed the control diet or the diet containing oligosaccharide for the next 12 days. The number of fecal bifidobacteria increased significantly in groups fed oligosaccharide diet. Elevated blood glucose concentration after STZ injection declined faster in the oligosaccharide fed group. Liver thiobarbituric acid reactive substance concentration, as an indicator of oxidative stress, did not increase in groups fed the oligosaccharide diet after the STZ injection. In addition, these groups had significantly higher glutathione peroxidase activity both in the plasma and the liver than groups fed the control diet. The results of this study suggest that soybean oligosaccharide has a beneficial effect in reducing oxidative stress in streptozotocin-injected rats.