• Journal of the Korea Concrete Institute
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• v.19 no.4
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• pp.515-525
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• 2007

In this investigation, results of laboratory tests on four reinforced concrete flat plate interior connections with elongated rectangular column support which has been used widely in tall residential buildings are presented. The purpose of this study is to evaluate an effect of column aspect ratio (${\beta}_c={c_1}/{c_2}$=side length ratio of column section in the direction of lateral loading $(c_1)$ to the direction of perpendicular to $c_1$) on the hysteretic behavior under earthquake type loading. The aspect ratio of column section was taken as $0.5{\sim}3\;(c_1/c_2=1/2,\;1/1,\;2/1,\;3/1)$ and the column perimeter was held constant at 1200mm in order to achieve nominal vertical shear strength $(V_c)$ uniformly. Other design parameters such as flexural reinforcement ratio $(\rho)$ of the slab and concrete strength$(f_{ck})$ was kept constant as ${\rho}=1.0%$ and $f_{ck}=40MPa$, respectively. Gravity shear load $(V_g)$ was applied by 30 percent of nominal vertical shear strength $(0.3V_o)$ of the specimen. Experimental observations on punching failure pattern, peak lateral-load and story drift ratio at punching failure, stiffness degradation and energy dissipation in the hysteresis loop, and steel and concrete strain distributions near the column support were examined and discussed in accordance with different column aspect ratio. Eccentric shear stress model of ACI 318-05 was evaluated with experimental results. A fraction of transferring moment by shear and flexure in the design code was analyzed based on the test results.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.3
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• pp.313-320
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• 2013

Purpose: This study compared the quantity of phoria for distance by new method with that by existing methods. Methods: For this study, it was selected to two existing phoria measurements, von Graefe and Maddox rod. And new method named "3D polarizing phoria measurement" was designed to measure the quantity of phoria using polarizing glasses and 3D display. Unlike existing measurement using polarized lens, newly considered method measured the quantity of phoria in condition removed perfect binocular fusion using field stop on apparatus and polarized lens. For using new method for distance, it was developed a phoria test chart. It supports three kinds of phoria measurements. Subjects were 12 (male 6, female 6). They had three phoria tests (1 sets) including new method. It was considered the effect of experimental order, so we tested all cases about experimental order. The number of cases was 6 sets, and the sample size in this experiment was 72 sets. For removing binocular fusion, lighting of the laboratory that was below 10 lx and the background color of phoria test chart was dark, RGB=(20, 20, 20). Results: Subjects were sorted into three groups. Samples with exophoria and orthophoria were 30 sets each, and those with esophoria were 12 sets. The quantity of phoria measured three tests differ from each other like "newmethod < von Graefe < Maddox rod", and there were statistically significant difference each other. Conclusions: This study has great significance in the sense that new method was the measurement with naturally removing binocular fusion without dizziness during the tests.

• Food Science of Animal Resources
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• v.33 no.3
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• pp.403-410
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• 2013

This study was performed to evaluate the microbiological contamination level of raw beef from retail markets in Seoul, Korea. The sampling and laboratory test were performed according to the procedure of "Standard for processing and ingredients specification of livestock product" and "Korean food code". Enterotoxin of Staphylococcus aureus isolates were detected using VIDAS$^{(R)}$ and PCR-based methods. Listeria monocytogenes serotyping and genotyping were carried out using Listeria antisera and L. monocytogenes Fingerprinting kit, respectively. A total of 48 samples were collected from 16 retail markets (butcher's shop: 5, department store: 6, supermarket: 5) in 2011. The level of total bacteria counts in the butcher's shop, department store and supermarket were $4.4{\times}10^3$ CFU/g, $3.9{\times}10^5$ CFU/g and $1.0{\times}10^4$ CFU/g, respectively. The concentrations of Escherichia coli of these three retail markets were $6.4{\times}10$ CFU/g, 7.6 CFU/g and $2.0{\times}10$ CFU/g, respectively. Salmonella species was not detected on all samples. However, S. aureus was isolated in the 3 samples (6.25%) from each type of three retail markets. L. monocytogenes was isolated in the 4 samples (8.3%) from department stores. The level of contamination of these foodborne bacteria was less than 100 CFU/g. The enterotoxin-encoding genes of S. aureus isolates were sea, seh, sei and sep gene. The gene similarity of L. monocytogenes isolated from two retail markets by Rep-PCR showed 57.8-98.1% and 68.1-98.1%, respectively. These results suggest that the HACCP guideline for environmental control in slaughterhouse and retail markets should be provided to prevent cross contamination and manage foodborne pathogens such as L. monocytogenes and S. aureus.

• Journal of the Korean Geosynthetics Society
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• v.20 no.4
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• pp.85-93
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• 2021

The seventy percentage of Korean Peninsular is covered by the mountainous area, and the depth of west sea and south sea is relatively shallow. Therefore, a large scale land reclamation from the sea has been implemented for the construction of industrial complex, residental area, and port and airport facilities. The common problem of reclaimed land is consisted of soft ground, and hence it has low load bearing capacity as well as excessive settlement upon loading on the ground surface. The hollow concrete block has been used to reinforce the loose and soft foundation soil where the medium-high apartment or one-story industrial building is being planned to be built. Recently the earthquakes with the magnitude of 4.0~5.0 have been occurred in the west coastal and southeast coastal areas. Lee (2019) reported the advantages of hollow concrete block reinforced shallow foundation through the static laboratory bearing capacity tests. In this study, the dynamic behavior of hollow concrete block reinforced sandy ground with filling the crushed stone in the hollow space has been investigated by the means of shaking table test with the size of shaking table 1000 mm × 1000 mm. Three types of seismic wave, that is, Ofunato, Hachinohe, Artificial, and two different accelerations (0.154 g, 0.22 g) were applied in the shaking table tests. The horizontal displacement of structure which is situated right above the hollow concrete block reinforced ground was measured by using the LVDT. The relative density of soil ground are varied with 45%, 65%, and 85%, respectively, to investigate the effectiveness of reinforcement by hollow block and measured the magnitude of lateral movement, and compared with the limit value of 0.015h (Building Earthquake Code, 2019). Based on the results of shaking table test for hollow concrete block reinforced sandy ground, honeycell type hollow block gives a large interlocking force due to the filling of crushed stone in the hollow space as well as a great interface friction force by the confining pressure and punching resistance along the inside and outside of hollow concrete block. All these factors are contributed to reduce the great amount of horizontal displacement during the shaking table test. Finally, hollow concrete block reinforced sandy ground for shallow foundation is provided an outstanding reinforced method for medium-high building irrespective of seismic wave and moderate accelerations.

• Journal of Food Hygiene and Safety
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• v.27 no.1
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• pp.42-49
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• 2012

This study was carried out to investigate the toxicity of food Red No.2 in the Sprague-Dawley (SD) female rat for 4 weeks. SD rats were orally administered for 28 days, with dosage of 500, 1,000, 2,000 mg/kg/day. Animals treated with food Red No.2 did not cause any death and show any clinical signs. They did not show any significant changes of body weight, feed uptake and water consumption. There were not significantly different from the control group in urinalysis, hematological, serum biochemical value and histopathological examination. In conclusion, 4 weeks of the repetitive oral medication of food Red No.2 has resulted no alteration of toxicity according to the test materials in the group of female rats with injection of 2,000 mg/kg. Therefore, food Red No.2 was not indicated to have any toxic effect in the SD rats, when it was orally administered below the dosage 2,000 mg/kg/day for 4 weeks.