• Journal of the Korean Society of Industry Convergence
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• v.25 no.6_3
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• pp.1165-1171
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• 2022

In this paper, the results of an experimental study were presented by measuring and comparing the flexural strength and deformation on the carbon fiber sheet strength reinforced concrete beam considering end anchorage effect. For this purpose, total six specimens of 100×100×600mm size were prepared and tested according to the KDS 14 20 20. The specimens were categorized in three cases as reference beams without strengthening, beams carbon fiber strengthened but not anchored and beams carbon fiber strengthened also anchored. Experimental results showed that the end anchorage contributed to increase the flexural strength about 42% greater than that of carbon fiber sheets alone, and the number and width of cracks were relatively increased. The results support a considerable effects of end anchorage for carbon fiber strengthened reinforced concrete beams in enhancing the flexural performance. Further studies are needed in durability and long term behavior of carbon fiber sheet strengthened reinforced concrete beams.

• Journal of the Korea Concrete Institute
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• v.24 no.4
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• pp.415-422
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• 2012

This paper analyzed seventy eight previous test results to evaluate bond strength of Near Surface-Mounted (NSM) FRP and prediction formulas previously proposed by researchers. The results showed that the most reliable bond strength prediction was the one proposed by Seracino, who considered the shape coefficient (ratio of width-thickness) and stiffness of FRP. However, the equation tended to underestimate the bond strength, especially serious when FRP bond length was relatively short, because the equation did not consider the effect of bond length. Based on the analysis of previous test results, the relation between bond length and bond strength and the group effect due to close proximity of FRPs were determined. Based on the findings, the Seracino's formula was modified and it's applicability was evaluated. The result showed that the suggested formula can be used effectively to predict the bond strength of NSM FRP.

• Fashion & Textile Research Journal
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• v.14 no.4
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• pp.641-647
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• 2012

This study investigates the sound properties of fabric frictional sound (SPL, ${\Delta}L$, ${\Delta}f$) according to the film type of PTFE laminated vapor-permeable water-repellent fabrics in order to understand the relationship between SPL and the basic properties of fabrics such as layer, yarn type, and thickness of fiber. This study accesses their mechanical properties and determines how to control them to minimize SPL. Eight PTFE laminated water-repellent fabrics, composed of four different film types (A, B, C, D) and with two different fabrics, were used as test specimens. Frictional sounds generated at 1.21m/s were recorded by using a fabric sound generator and SPLs were analyzed through Fast Fourier Transformation (FFT). The mechanical properties of fabrics were measured by KES-FB. The SPL value was lowest at 74.4dB in film type A and highest as 85.5dB in type D. Based on ANOVA and post-hoc test, specimens were classified into less Loud Group (A, B) and Loud Group (C, D). It was shown that SPL was lower when 2 layer (instead of 3 layer), filament yarn than staple, and thin fiber than thick were used. In Group I, shearing properties (G, 2HG5), geometrical roughness (SMD), compressional properties (LC, RC) and weight (W) showed high correlation with SPL however, elongation (EM) and shear stiffness (G) did with SPL in Group II.

• Journal of the East Asian Society of Dietary Life
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• v.17 no.4
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• pp.563-570
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• 2007

This study was performed to observe the antioxidative effects, antimutagenic capacity, and cytotoxic activity of the 70% ethanol extract, and fractions, of Agaricus blazei Murill mycelium, using DPPH free radical scavenging ability, the Ames test, and SRB assay, respectively. Among the fractions, ethyl acetate showed the most effective antioxidative capacity according to the $RC_{50}$(73.6 $\mu$g/mL) of the scavenging effect on the DPPH radical. The inhibition rate of both the aqueous fraction and 70% ethanol extract(200 $\mu$g/plate) toward the Salmonella typhimurium TA100 strain was 94.6%, and it was 89.4% against the mutagenesis induced by MNNG(0.4 $\mu$g/plate). In addition, an identical concentration of the 70% ethanol extract in the TA98 strain, and the ethyl acetate fraction in the TA100 strain, showed inhibition rates of 80.3% and 76.9%, respectively, the highest activities against the mutagenesis induced by 4NQO(0.15 $\mu$g/plate). The cytotoxic effects of the 70% ethanol extract and its fractions increased with increasing sample concentration against human cervical adenocarcinoma(HeLa), human hepatocellular carcinoma(Hep3B), human breast adenocarcinoma(MCF-7), human stomach adenocarcinoma(AGS), and human lung carcinoma (A549). A 1 mg/mL concentration of the ethyl acetate fraction showed cytotoxicities of 77%, 83.8%, 82.1%, 83.1%, and 92.6% against HeLa, Hep3B, MCF-7, AGS and A549, respectively.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.3
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• pp.153-158
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• 2020

In this study, a numerical approach for evaluating the resisting capacity of a partial concrete-filled steel tube (CFST) column is introduced. By strengthening the plastic hinge part of a traditional reinforced concrete column with a steel tube, a partial CFST shows a similar bending moment capacity as that of a full CFST column but with reduced material cost. To conduct an elaborate numerical analysis of a partial CFST column, an improved bond-slip model is applied to a finite element (FE) model at the interface between the steel tube and in-filled concrete. This numerical model is verified through the results of a double curvature bending-compression test. A parametric study with the proposed numerical model is used to obtain the load moment interaction diagrams for evaluating the resisting capacity based on various dimensions. Finally, the required strengthening length is estimated for each degree of thickness of the steel tube, and the failure mechanism of the partial CFST column based on the dimensions of the steel tube are identified.

• Korean Journal of Materials Research
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• v.20 no.6
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• pp.319-325
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• 2010

3-D IC integration enables the smallest form factor and highest performance due to the shortest and most plentiful interconnects between chips. Direct metal bonding has several advantages over the solder-based bonding, including lower electrical resistivity, better electromigration resistance and more reduced interconnect RC delay, while high process temperature is one of the major bottlenecks of metal direct bonding because it can negatively influence device reliability and manufacturing yield. We performed quantitative analyses of the interfacial properties of Al-Al bonds with varying process parameters, bonding temperature, bonding time, and bonding environment. A 4-point bending method was used to measure the interfacial adhesion energy. The quantitative interfacial adhesion energy measured by a 4-point bending test shows 1.33, 2.25, and $6.44\;J/m^2$ for 400, 450, and $500^{\circ}C$, respectively, in a $N_2$ atmosphere. Increasing the bonding time from 1 to 4 hrs enhanced the interfacial fracture toughness while the effects of forming gas were negligible, which were correlated to the bonding interface analysis results. XPS depth analysis results on the delaminated interfaces showed that the relative area fraction of aluminum oxide to the pure aluminum phase near the bonding surfaces match well the variations of interfacial adhesion energies with bonding process conditions.

• CELLMED
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• v.1 no.1
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• pp.7.1-7.9
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• 2011

Bioelectric impedance measurements have been reported to show significant variation between individuals. Different physiological conditions like thickened skin, obesity, and fluid retention can affect the impedance measurement. Therefore, it is important to learn what other factors can affect the measurements of impedance even in healthy individuals. Such information is a prerequisite for understanding the changes in impedance associated with acupuncture treatment. This study investigated the bio-impedance properties of tissue segments in the arms of a number of healthy subjects, so as to define the factors that might influence the variation of the bio-impedance data in acupuncture meridians studies. 51 healthy subjects were recruited through Liverpool Hospital, Sydney. Demographic data was collected from each subject including the age, sex, BMI, and time since most recent meal. Electrodes were applied to the forearms of each test subject. Measurements were done by a purpose-built Bio-Impedance Research Device (BIRD-I) which allowed the determination of core resistance (Rc) and core reactance (Xc) of each of the three meridian tissue segments on the anterior surface of the forearm. No significant difference was found in the core resistance attributable to age group, gender, BMI or meal intake. However, a statistically significant trend in increasing resistance from the radial to ulnar aspect of the forearm (p < 0.001) was found. No significant difference was found in the core resistance of test tissue segments among the 51 healthy subjects measured in this study. However, the trend of increasing core resistance from the radial to ulnar aspects of the arm deserves further investigation.

• Journal of the Korea Concrete Institute
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• v.17 no.1 s.85
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• pp.113-120
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• 2005

The purpose of this study is to investigate the strength and ductility improvement of columns retrofitted by steel-fiber composite plate. Test specimens strengthened by three different materials - steel plate(SP), carbon fiber sheet(CF) and fiber-steel composite plate(CP) - were tested under cyclic lateral load with a constant axial load equal to $20\%$ of the axial compression capacity. The structural capacity of composite plate was good or better than that of other retrofitting materials. Test results from all retrofitted specimens showed that considerably higher retrofitting amount was required for strength enhancement. The ductility of retrofitted columns by composite plate was fairly improved. Also, energy ductility ratio was more effective than displacement ductility ratio for ductility estimation of retrofitted column.

• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.3
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• pp.215-223
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• 2013

An experimental research on the possibility of using fiber reinforced concrete precast tunnel segments instead of traditional reinforced concrete(RC) segment has been performed in europe. This solution allows removing the traditional reinforcement with several advantages in terms of quality and cost reduction. Full-scale bending tests were carried out in order to compare the behaviour of the segments under flexural actions on both rebar reinforced concrete and rebar-fiber reinforced elements. The test results showed that the fiber reinforced concrete can substitute the traditional reinforcement; in particular the segment performance is improved by the fiber presence, mainly in terms of crack.

• Proceedings of KOSOMES biannual meeting
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• 2003.05a
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• pp.125-134
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• 2003

This paper describes on the design of Passive-type Radar Reflector for small Ship (PRR-S) based on the newly revised 2000 SOLAS regulations. The design idea, adopted in the study, is to hold PRR-S in the proper ‘catch rain’ position to avoid fluctuations of Radar Cross Section (RCS) due to ship's heeling. The PRR-S consists of octahedral-type radar reflector with circular plates and three-axis gimbaled stabilizer with weight on the bottom of outer gimbal ring. Performance test for the PRR is carried out in an anechoic chamber. The test results show that the reflected radar signal from PRR-S is more uniformly distributed than the reference model (Davis Echomaster).