• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.1
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• pp.181-194
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• 2013

Landslides are known as gravitational mass movements that can carry the flow materials ranging in size from clay to boulders. The various types of landslides are differentiated by rate and depositional features. Indeed, flow characteristics are observed from very slow-moving landslides (e.g., mud slide and mud flow) to very fast-moving landslides (e.g., debris avalanches and debris flows). From a geomechanical point of view, shear-rate-dependent shear strength should be examined in landslides. This paper presents the design of advanced ring-shear apparatus to measure the undrained shear strength of debris flow materials in Korea. As updated from conventional ring-shear apparatus, this apparatus can evaluate the shear strength under different conditions of saturation, drainage and consolidation. We also briefly discussed on the ring shear apparatus for enforcing sealing and rotation control. For the materials with sands and gravels, an undrained ring-shear test was carried out simulating the undrained loading process that takes place in the pre-existing slip surface. We have observed typical evolution of shear strength that found in the literature. This paper presents the research background and expected results from the ring-shear apparatus. At high shear speed, a temporary liquefaction and grain-crushing occurred in the sliding zone may take an important role in the long-runout landslide motion. Strength in rheology can be also determined in post-failure dynamics using ring-shear apparatus and be utilized in debris flow mobility.

• Archives of Reconstructive Microsurgery
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• v.9 no.2
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• pp.114-119
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• 2000

The soft tissue defects including the Achilles tendon are complex and very difficult to reconstruct. Recently, several free composite flaps including the tendon have been used to reconstruct large defects in this area in an one-stage effort. Our case presents a patient reconstructed with free composite dorsalis pedis flap along with the extensor digitorum longus and superficial peroneal nerve for extensive defects of the Achilles tendon and surrounding soft tissue. A 36-year-old-man sustained an open injury to the Achilles tendon. He was referred to our department with gross infection of the wound and complete rupture of the tendon associated with loss of skin following reduction of distal tibial bone fracture. After extensive debridement, $6{\times}8cm$ of skin loss and 8cm of tendon defect was noted. Corresponding to the size of the defect, the composite dorsalis pedis flap was raised as a neurosensory unit including the extensor digitorum longus to provide tendon repair and sensate skin for an one-stage reconstruction. One tendon slip was sutured to the soleus musculotendinous portion, the other two were sutured to the gastrocnemius musculotendinous portion with 2-0 Prolene. The superficial peroneal nerve was then coaptated to the medial sural cutaneous nerve. The anterior tibial artery and vein were anastomosed to the posterior tibial artery and accompanying vein in an end to end fashion. After 12 months of follow-up, 5 degrees of dorsiflexion due to the checkrein deformity and 58 degrees of plantar flexion was achieved. The patient was able to walk without crutches. Twopoint discrimination and moving two-point discrimination were more than 1mm at the transferred flap site. The donor site healed uneventfully. Of the various free composite flaps for the Achilles tendon reconstruction when skin coverage is also needed, we recommand the composite dorsalis pedis flap. The advantages such as to control infection, adequate restoration of ankle contour for normal foot wear, transfer of the long tendinous portion, and protective sensation makes this flap our first choice for reconstruction of soft tissue defect including the Achilles tendon.

• Journal of Nutrition and Health
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• v.12 no.4
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• pp.29-42
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• 1979

In order to observe metabolic effects of an oral conceptive, Norinyle, on female Guinea pig, the changes of ascorbic acid amount and alkaline phosphatase activity in the liver and serum were determined, and histochemical changes of the uterus were observed by microscopic and electronmicroscopic methods by administration of Norinyle with or without ascorbic acid. The results obtained are summerized as follows: 1) The metabolic changes were clearly influenced by the administration of Norinyle alone, but the changes were diminshed by administration of Norinyle with ascorbic acid. 2) The adimnistration of Norinyle influenced to increases the requirment of ascorbic acid in the liver. 3) The uterus weight of the Norinyle administered group was much increased, while the weight was less increased in the group of administered Norinyle with ascorbic acid than the control. 4) The Norinyle administration was brought about an atrophy of endometrium, of uterus especially, functional layer, that the formation of glands were inadequately and the fromation of basal layer and stroma were diminished. 5) An acute infarction on the all layers of the uterus was developed at 9th and 25th days of Norinyle administration and 20th day of Norinyle with ascorbic acid administration. 6) A hypertrophy of stromal and endovascular cells were observed on the groups administered of Norinyle alone(group II ) or Norinyle with ascorbic acid(group IV). 7) It was observed that amount of collagen fiber in the basal and muscular layeres of uterus were diminished under a microscopical observation by the special stained specimen on the Norinyle administered group, but the amount and distribution of reticulin fiber were not changed significantly. 8) The fille structure of outer functional layer of the uterus were significantly changed by administration of Norinyle which were shown irregurarity of nuclear membrane, poor development ana significant expansion of enaoplasmic reticulum, decreases of the amount of ribosome due to slip off, increases of the number of dense bodies, obvious formation of vaccule, an4 decreases the amount of collagen in inner and outer layer of the stroma. 9) The amount of ascorbic acid in the serum did not much changed but the amount in the liver was much decreased by the administration of Norinyle, And the administration of Norinyle with ascorbic acid induced for a significant diminishing on the changes of uterus which might be able to developed by the administration of Norinyle alone.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.3
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• pp.21-31
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• 2018

This paper presents an experimental investigation on the structural performance of precast ribbed panel specimens and bridge deck specimens fabricated from the panels. The panel specimens are developed for permanent deck forms of railway bridges (PSC girder). The decks of railway bridges have short lengths compared with highway bridges. Therefore, precast panels for railway bridges are different from those of highway bridges. The precast panels have ribs designed for crack control at the bottom of the sections. Two kinds of specimens were examined: one with 400-mm width and one with 1200-mm width. Three specimens of each type were fabricated, and a total of 12 specimens were tested. In this test, the ultimate load, strain of the reinforcement and concrete, crack width, deformation, and slip were measured. The structural performance of the specimens was assessed using the Korea railway bridge design code and Eurocode. All specimens met the current design criteria for structural strength and serviceability.

• Journal of the Korean Society for Advanced Composite Structures
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• v.3 no.1
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• pp.8-15
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• 2012

The initial clamping forces of high strength bolts depending on different faying surface conditions drop within 1,000 hours regardless of loading, any other external force or loosening of the nut. This study is focused on an expectation model for relaxation of high strength bolt, which is confined to creep on coated faying surfaces after initial clamping. The range of this experiment is limited to estimate the relaxation of bolted joints coated by inorganic zinc primer. The candidate bolts were dacro-coated tension control bolts. The parameters of coated thickness for the faying surface were 96, 168,and $226{\mu}m$ respectively. From experiments, it exhibited that the logarithmic function for creep strain was derived due to the parameter of coating thickness. By using the creep strain, subsequently the quantitative model for estimating long term relaxation of high strength bolt can be taken with the elapsed time. The experimental results showed that the relaxation after the initial clamping of high strength bolt rose to a much higher range from 10% to 18% due to creep of the coating as the coating thickness was increased. This study showed that the clamping force reflecting relaxation after the elapse of constant time can be calculated from the initial clamping force of high strength bolt.

• Journal of the Korea Concrete Institute
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• v.19 no.4
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• pp.467-474
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• 2007

In this paper, a total of 13 beams with bonding, anchorage system, amount of prestressing and span length as variables of experiment were tested in flexural test and analyzed in finite element analysis; one control beam, two simplified FRP-boned beams, four prestressed FRP-unbonded beams and four prestressed FRP-bonded beams. Also, a nonlinear finite element analysis of beams in the flexural test is performed by DIANA program considered material nonlinear of concrete, reinforcement and the interfacial bond-slip model between concrete and CFRP plates. The failure mode of prestressed CFRP plated-beams is not debonding but FRP rupture. RC members strengthened with external bonded prestressed CFRP plates occurred 1st and 2nd debonding of the composite material. After the debonding of CFRP plates occurs in bonded system, behavior of bonded CFRP-plated beams change into that of unbonded CFRP-plated beams due to fix of the anchorage system. Also, It was compared flexural test results and analytical results of RC members strengthened with CFRF plates. The ductility of beams strengthened by CFRP plates with the anchorage system is considered high with the ductility index of above 3. Analysis results showed a good agreement with experiment results in the debonding load, yield load and ultimate load.

• Journal of the Korean Geosynthetics Society
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• v.9 no.3
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• pp.87-93
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• 2010

The change of water level in reservoirs is an important factor causing failure of bank slopes, i.e. landslide. The water level of Three Gorges reservoir in China fluctuate between 145 m and 175 m, as a matter of flood control. During its normal operational state, the rate of water level fluctuation is supposed to range from 0.67 m/d to 3.0 m/d. Majiagou slope is located on the left bank of Zhaxi River, 2.1 km up from the outlet. Zhaxi River is a tributary of the Yangtze River within the Three Gorges area, of which the water level changes with the reservoir. At the back of Majiagou slope, a 20 m long and 3~10 cm wide fissure developed just after the reservoir water level rose from 95 m to 135 m in 2003. This big fissure was a full suggestion of potential failure of this slope. In this study, the pore water pressure files obtained from seepage analysis were used to evaluate the change in factor of safety (FS) with reservoir water level. Slope stability analyses then were carried out, with fully specified slip surface and limit equilibrium method. In the limit equilibrium analysis, the contribution of negative pore water pressure to shear strength was considered by the use of Fredlund's shear strength equation for unsaturated soils. On the base of the analyses, the change of FS with reservoir water level was interpreted in detail. It was found that FS against bank slopes decreases with the rise of the reservoir water level and increases with the drawdown of the reservoir water level. The most dangerous state was when the reservoir water level stays at the highest for a long time.

• Korean Journal of Health Education and Promotion
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• v.19 no.2
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• pp.57-72
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• 2002

Students spend most of their time in school. Schools have the possibility of unanticipated accidents, however, and the rate of accidents in schools is increasing. The purpose of this study were to understand the accidents that arise in schools as well as the school safety management system and by analyzing affects that school safety management system has on accidents in schools, to come lip with a preventive plan. 906 high school sophomore students attending in Seoul were surveyed 1Tom November 12th to 23rd 2001. The results were following: 1. Students surveyed comprised of the following: Male 48.9%, Female 51.1% Public Schools 32.6%, Private Schools 67.4% Boys Schools 48.9%, Girls Schools 51.1% 2. In the past year, male students had more accidents(p〈.05) in school. 3. In examining students safety management control, 94.0% said that, there is an infirmary, there is a clear distinction between the playing fields and pathways(74.8%), and the chemicals in the labs are kept in a safe manner(77.2%). The above items were generally well maintained. However, the following recorded low scores. There are warning signs in hazardous places and facilities(30.5%), There is guiding principle to examine the safeness on a regular basis(24.9%), and There are slogans and posters preventing accidents(40.3%). 4. In examining the facilities of the schools that were surveyed, the majority answered, yes to the following. There are hazardous facilities or materials at school(62.9%), There are sharp edges in educational supplies and equipment(59.8%), There are nails or other components that are sticking out of desks and chairs(75.9%), There are slippery spots in the corridors and classrooms(69.3%), There are stones, scrap metal, broken glass, and trash on the playing fields(66.6%). Furthermore, the students surveyed said, yes to the following although in low percentages. The amount of sand on the playing fields is sufficient(49.1%), The soccer and basket goal posts are fastened (53.7%), There are safety bars on the windows of classrooms and corridors (27.4%), There are safety mats on the entrance to restrooms preventing slips (14.2%), The stairs have slip protection measures(49.1%). 5. In analyzing the affect that the school safety management system has on accidents in school, schools that had slogans and posters preventing accidents had a 50% less chance of accidents(p〈.05), schools with chemicals and equipment in the labs that were safely maintained had an 80% less probability of accidents(p〈.0l), and the schools that had sharp edges in the educational supplies and equipment had an 80% greater chance of accidents(p〈.01).

• Economic and Environmental Geology
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• v.54 no.6
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• pp.615-627
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• 2021

The Baekildo fault, a dextral strike-slip fault developed in Baekil Island, Goheung-gun, controls the distribution of tuffaceous sandstone and lapilli tuff and shows a complex fracture system around it. In this study, we examined the spatial variation in the geometry and connectivity of the fracture system by using circular sampling and topological analysis based on a detailed fracture trace map. As a result, both intensity and connectivity of the fracture system are higher in tuffaceous sandstone than in lapilli tuff. Furthermore, the degree of the orientation dispersion, intensity, and average length of fracture sets vary depending on the along-strike variation in structural position in the tuffaceous sandstone. Notably, curved fractures abutting the fault at a high angle occur at a fault bend. Based on the detailed observation and analyses of the fracture system, we conclude as follows: (1) the high intensity of the fracture system in the tuffaceous sandstone is caused by the higher content of brittle minerals such as quartz and feldspar. (2) the connectivity of the fracture system gets higher with the increase in the diversity and average length of the fracture sets. Finally, (3) the fault bend with geometric irregularity is interpreted to concentrate and disturb the local stress leading to the curved fractures abutting the fault at a high angle. This contribution will provide important insight into various geologic and structural factors that control the development of fracture systems around faults.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.3
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• pp.338-345
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• 2009

Scaled-up low-trans shortening (LTS) was produced by lipase-catalyzed interesterification. Blend of rice bran oil (RBO), palm stearin (PS) and high oleic sunflower seed oil (HO) with 1:2:0.9 (w/w/w) ratio was interesterified using immobilized lipase from Thermomyces lanuginosus (TLIM) in the batch type reactor at $65^{\circ}C$ for 24 hr, and physicochemical melting properties of LTS were compared with commercial shortening. Solid fat content (SFC) of commercial shortening (used as control) and LTS was similar at 9.56 and 8.77%, respectively, at $35^{\circ}C$. Major fatty acids in LTS were C16:1 (33.7 wt%), C18:1 (45.7 wt%) and C18:2 (13.4 wt%). Trans fatty acid content in the commercial shortening (4.8 wt%) was higher than that of LTS (0.5 wt%). After reverse-phase HPLC analysis, major triacylglycerol (TAG) species in LTS were POO, POP and PLO. Total tocopherol, ${\gamma}$-oryzanol and phytosterol contents in the LTS were 12.37, 0.43 and 251.38 mg/100 g, respectively. Hardness of LTS was similar to that of commercial shortening. Also, x-ray diffraction analysis showed coexistence of ${\beta}'$ and ${\beta}$ form in the LTS.