• Composites Research
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• v.13 no.4
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• pp.42-53
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• 2000

A study has been made to establish an optimum condition in the surface treatment and curing method that is important for the fabrication of Al 7075/CFRP laminates. PAA(Phosphoric Acid Anodizing) provided a good adhesive strength and FPL(Sulfuric / Sodium Dichromate Acid Etching) had a similar adhesive strength with PAA. On the other hand, the poor adhesive strength was shown on vapor degrease and CAA(Chromic Acid Anodizing). By using the atomic force microscope(AFM), it was found that the PAA oxide surface obviously had a greater degree of microroughness as compared to vapor degrease, CAA and FPL treated surfaces. These results support the concept of a mechanical interlocking of the adhesive with-in the oxide pores as the predominant adhesion mechanism. In curing methods, the adhesive strength of co-curing method was higher than that of secondary curing method. With respect to stability of specimen shape, the secondary curing method was better than co-curing method. DMA(Dynamic Mechanical Analysis) test revealed $T_g$ in curing times over 60 min is nearly same, so it is estimated they will have similar degree of curing and joint durability in using FM300M adhesive film.

• Tunnel and Underground Space
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• v.17 no.3 s.68
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• pp.203-215
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• 2007

Stability and mechanical deformation behavior of rock masses are highly dependent on the mechanical characteristics of contained discontinuities. Therefore, mechanical characteristics of the discontinuities should be considered in the design of tunnel and underground structures. In this study, direct shear tests for rough granite joints were carried out under constant normal stiffness conditions. Effects of initial normal stress, shear velocity, and surface roughness on the characteristics of shear strength and deformation behaviors were examined. Results of shear testing under constant normal stiffness conditions reveal that shear behaviors could be classified into two categories, based on the amount of decrease in shear stress at the Int peak shear stress. With initial normal stiffness increasing, it turned out that shear displacement at peak stress and the first peak shear stress increased, however friction angle and friction coefficient showed decrease. In case of shear stiffness and average friction coefficient, it turned out that they are not dependent on the initial normal stress. Minor effects of shear velocity on rough joints were observed in several shear quantities. However, the effects of shear velocity were insignificant regardless of the normal stress increase. Change of shear strength and deformation characteristics on joint roughness were examined, however, it turned out that the variations were attributed to deviation of shear test specimens.

• Journal of the Korea Society of Computer and Information
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• v.18 no.12
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• pp.149-157
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• 2013

The purpose of this study is to listen to vivid story on economic life of marriage immigrant women using phenomenological study out of qualitative study methods, and to analyze the meaning of dynamicity of experiences through in-depth interviews. The research question is "What is the meaning of economic life that marriage immigrant women experience?" From the research, 67 meaningful statements were abstracted and 15 core meanings were organized. The 15 core meanings were categorized as 5 theme categories such as 'Tough Life', 'Unstable Income such as Children Education Expense and Insurance Premium', 'Search for Changes in Life Style for Adaptation', 'Pursuit of Economic Stability through Employment', 'Expectation of Supports and Return to Married Woman's Parents' Home.' The researcher made structural description through first person speaker for the application of hermeneutical writing. In other words, the meaning of economic life of marriage immigrant women in Korea is 'difficult coping process to family-oriented culture pursuing changes in life style to adapt themselves to difficult reality.' Various undertones of practice were proposed through those statements such as policy to expand opportunities to receive an old-age pension by applying 'Joint Scheme for Couples' (Virtual Name) to People's pension for stable economic life of marriage immigrant women in old age.

• Journal of the Korean Geophysical Society
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• v.9 no.2
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• pp.121-128
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• 2006

Recently, spillways are need to control stable water level for supporting main dams because of floods by unusual change of weather such as Typhoon Rusa. This study has been focused on the amount of leakage through the rock mass distributed fractures and joints under the opened emergency spillway. It is very important to evaluate the amount of leakage as these affect stability of spillway by interaction between effective stress and pore pressure. The commercial program MAFIC has been used for analyzing groundwater flow in fractured rock mass. The results showed that the values of range, average and deviation of leakage were 2.85∼ 3.79×10-1, 3.32×10-1 and 1.70×10-2 m3/day/m2 respectively. Secondary, we have estimated the effect of grouting after the transmissivity(Tf) of joint 1 as main pathway of leakage known from above results was changed from 1.78×10-7 to 1.59×10-9 m2/s. The results showed that the values of range, average and deviation of leakage were 7.80×10-4∼1.53×10-3, 1.18×10-3 and 1.32×10-4 m3/day/m2 respectively. As the result, the amount of leakage after grouting has been decreased by a ratio of 1 to 277.

• Journal of the Korean Geosynthetics Society
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• v.17 no.4
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• pp.1-10
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• 2018

Although the soil nailing method is generally used as a gravity grouting, the development and application of pressurized grouting method has recently increased to address the problem of joint generation and filling due to grouting. Pressurized grouting of the soil nailing method is generally used in combination with ordinary portland cement and water. In the field, the cement is mixed with the rapid setting cement to reduce curing time because ordinary portland cement takes more than 10 days to satisfy the required strength. In this study, uniaxial compression tests and laboratory tests were carried out to confirm the efficiency of the grouting material according to the mixing ratio of rapid setting cement. The mixing ratio of 30% grouting satisfies the required strength within 7 days and satisfies the optimum gel time. As a result of the laboratory test with granite weathered soil, the reinforcing effect was confirmed to be 1.5 times as compared with the gravity type at an injection time of 10 seconds and a strain of 15%. The friction resistance increases linearly with the increase of the injection time, but it is confirmed that the friction resistance decreases due to the hydraulic fracturing effect at the injection time exceeding the limit injection pressure. Numerical analysis was performed to compare the stability of slopes not reinforced with slopes reinforced with gravity and pressurized soil nailing.

• Journal of Veterinary Clinics
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• v.36 no.1
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• pp.53-61
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• 2019

Total hip arthroplasty (THA) is a successful surgical treatment for both patients with chronical lameness and dogs who are nonresponsive to medical treatments, providing excellent joint function for returning dogs to the normal gait in 80% to 98% of hip dysplasia (HD) patients. The THA surgical implant system manufactured by BioMedtrix and Kyon are today widely accepted. When comparing the BioMedtrix biological fixation (BFX) system to the BioMedtrix cemented fixation (CFX) system, the many advantages of BFX, which include longer potential implant life, decreased risk of postoperative or later infection, and better implant stability, become evident. However, BFX implies a greater risk of femoral fracture during reaming and requires a more precise surgical technique to achieve good implant fit, given the press-fit nature of cementless THA. The purposes of this study are to both describe the mistakes and complications during stem implantation for beginner surgeons with both the BFX and the CFX systems and to document the initial result of 12 implantations in canine cadavers. Given the detailed evaluations of 3 specialists, who are Diplomate American College of Veterinary Surgeons (DACVS), only 3 of 11 stems were appropriately sized. Specifically, 6 stems were anteverted rather than being retroverted; further, although 7 stems were coaxial with the femoral long axis in the frontal plane, the other stems were in the varus at the frontal plane, with the proximal medial stem adjacent to the medial femoral cortex. Moderate angulation from the cranial to the caudal directions was found in 4 cases in the sagittal plane. Additionally, 1 case of femoral fissure and 1 case of perforated femoral cortex were reported. It is not easy for surgeons performing cementless THA for the first time to achieve a good result, even though they completed an educational course about it and given that catastrophic complications often occurred during early surgical clinical cases. Therefore, ex-vivo studies are sincerely required to get an expertise by rehearsing the preparation of the femoral envelop in isolated bones. Further studies should be conducted to achieve both highly accurate implant size and correct orientation during the preoperative planning. Additionally, surgeons' learning curve should be examined in future investigations.

• Journal of the Korean Society of Radiology
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• v.15 no.3
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• pp.321-327
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• 2021

Wrist PA-grip view is used to diagnose triangular fibrocartilage complex (TFCC) tear because it can easily diagnose damage to the surrounding wrist ligaments. However, despite advances in radiology equipment, distortion of images due to geometric elements still has many limitations. In this paper, we propose a method that can minimize the distortions of images by analyzing the distortions occurring in the wrist PA-grip view. A source of image distance (SID) were set at 130 cm and 150 cm for comparison with 110 cm. Depending on the SID, the phantom of wrist was moved at 0, 2, 4, 6, 8, and 10 cm in the X-axis and Y-axis directions, respectively. For quantitative evaluation, the difference of distance between the radius and ulna was measured in picture archiving and communication system (PACS) system. As a qualitative evaluation, survey was conducted among 20 radiologic technologists who examined the Wrist PA-grip view. The Kruskal Wallis test was performed to compare the distortion according to the phantom movement in the X-axis and Y-axis directions based on the SID, and the Tukey test was performed as a post-test. In the quantitative evaluation results, the measured values obtained in the X-axis was not significantly different in all groups (p>0.05). The measured values obtained in the Y-axis was significantly different in the most groups (p<0.05). Therefore, to reduce distortion while maintaining image quality, we recommend what examine the SID at 150 cm than 110 cm.

• Herbal Formula Science
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• v.29 no.2
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• pp.81-91
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• 2021

Objectives : This study was conducted to evaluate the efficacy of a complex mixture of natural substances of ginseng and baeknyeoncho on the arthritic rats. Methods : In vitro experiments were conducted to ensure the stability of the complex. After setting toxicity and concentration by MTT assay, the antioxidant effect was measured through DPPH and ABTS radical scavenging activity. To confirm the anti-inflammatory effects of the complex, levels of nitric oxide (NO) and pro-inflammatory cytokines (IL-1β, TNF-α) were measured in LPS-treated macrophage cell lines (RAW264.7). We injected monosodium iodoacetate (MIA) 50 μl (60 mg/ml) into knee joints of rats to induce osteoarthritis. The rats were divided into three groups (normal (n=5), control (n=5), and OR (n=5) group). The control group consumed 2 mg/kg of physiological saline once a day for 4 weeks, and the OR group was mixed at a concentration of 416.5 mg/kg of Baengnyeoncho (O) and 208.25 mg/kg of red ginseng (R) and ingested 1 mL each 5 days a week. Results : This complex increased the DPPH and ABTS radical scavenging rate. The complex decreased NO production and pro-inflammatory cytokine production of macrophages. In the OR group, the secretion of cytokine in serum was decreased. In histopathological examination, the joint tissue of the composite showed less damage to the synovial membrane, cartilage, and fibrous tissue than the control group. Conclusions : As a result of this study, natural complexes have antioxidant, anti-inflammatory and cartilage protection effects. Therefore, we expect the complex to be effective in treating osteoarthritis.

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.3
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• pp.263-275
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• 2022

The loss of posterior occlusal support leads to further complications such as collapsed occlusal plane and reduced vertical dimension, and it may cause problems such as facial appearance change, reduced chewing efficiency, and temporomandibular joint disorders. In such case, it is necessary to re-establish occlusal plane and vertical dimension properly through accurate diagnosis and predictable treatment plan. This case report presents a 71-year-old female, whose occlusal plane was collapsed and posterior restorative space was insufficient. To perform a patient-friendly full mouth rehabilitation, proper vertical dimension and occlusal plane were decided by evaluation of interocclusal space at her physiologic mandibular rest position, swallowing, pronunciation, facial appearance, and the average length of anterior teeth. And then, the fixed provisional restorations were fabricated with the new occlusal position, and evaluated for 5 months with checking adaptation of masticatory muscles and any kind of clinical symptoms occurs or not. After confirmation of functional stability and esthetic satisfaction with the newly established occlusion, final definitive restorations were fabricated and inserted in the mouth. Through the above process, the treatment result was functionally and aesthetically satisfactory.

• Journal of the Korean Applied Science and Technology
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• v.40 no.2
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• pp.290-300
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• 2023

This study was understood the risk mechanism of falls in the elderly and reviewed previous research data to see if the principle of Pilates rehabilitation exercise could have a positive effect on balance ability and postural stabilization in the elderly, and the purpose of this study is to present literature-based data on the fall prevention effect of rehabilitation Pilates exercise. First, the rehabilitation Pilates exercise makes it available for strengthening the center of the body to stabilize the spine and pelvis and stimulates the nerve root, thereby having an effect on the balance and the joint stabilization. Second, a proprioceptive sensory impairment and a musculoskeletal degenerative disease due to aging increase the loss of balance ability and the instability in posture maintenance, thereby coming to raise the risk of a fall damage caused by the difficulty in performing motor functions and by the gait disturbance. Third, the rehabilitation Pilates exercise leads to improving the core muscle strength in older adults, resulting in being capable of expecting the betterment in the balance and the reaction time motor function. And there is a positive impact on the improvement in body imbalance and on the stability in movement involved in the fall prevention, resulting in being able to suggest the possibility of likely contributing to a reduction in a fall risk rate. In conclusion, the rehabilitation Pilates as the elderly exercise program showed effects on the improvement in the body's muscular strength, on the upgrade in a sense of balance, and on the stabilization of core. Thus, it was considered to diminish the risk factors for a fall damage caused by musculoskeletal degeneration and to be capable of preventing a serious disorder of activity due to a chronic senile disease.