• Journal of Korean Society of Steel Construction
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• v.17 no.3 s.76
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• pp.337-346
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• 2005

A composite bridge deck system assembled from a modular profile with double-rectangular cell has been developed for highway bridges. This study is focused on the experimental characterization of flexure performance of pultruded GFRP deck under static loading. Several tests were conducted on single modules and adhesively bonded 2 and 5-modules. The specimen details such as dimensions, material properties and fiber architecture, and experimental set-up and testing procedure have been addressed. It is found that the presented GFRP composite modular deck is very efficient for use in bridges.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.1
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• pp.90-95
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• 2005

Lactic acid bacteria were isolated from silage, which produce high level of hydrogen peroxide in cell culture supernatant. The 16S rDNA sequences of the isolate matched perfectly with that of Lactobacillus fermentum (99.9%), examined by a 16S rDNA gene sequence analysis and similarity search using the GenBank database, thus named L. fermentum CS12-1. L. fermentum CS12-1 showed resistance to low pH and bile acid. The production of hydrogen peroxide by L. fermentum CS12-1 was confirmed by catalase treatment and high-performance liquid chromatography. L. fermentum CS12-1 accumulated hydrogen peroxide in culture broth as cells grew, and the highest concentration of hydrogen peroxide reached 3.5 mM at the late stationary growth phase. The cell-free supernatant of L. fermentum CS12-1 both before and after neutralization inhibited the growth of enterotoxigenic Escherichia coli K88 that causes diarrhea in piglets.

• Food Science and Biotechnology
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• v.17 no.3
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• pp.489-494
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• 2008

In order to develop a potent antidementia $\beta$-secretase inhibitor from phytochemicals, $\beta$-secretase inhibitory activities of extracts from many medicinal plants and herbs were determined. Water extracts from Rubus coreanus showed the highest $\beta$-secretase inhibitory activity of 84.5%. After purification of the $\beta$-secretase inhibitor from R. coreanus using systematic solvent extraction, ultrafiltration, Sephadex G-10 column chromatography, and reverse-phase high performance liquid chromatography (HPLC), a purified $\beta$-secretase inhibitor with $IC_{50}$ inhibitory activity of $6.3{\times}10^3\;ng/mL$ ($1.56{\times}10^{-6}\;M)$ was obtained with a 0.08% solid yield. The molecular mass of the purified $\beta$-secretase inhibitor was estimated to be 576 Da by liquid chromatography-mass spectrometry (LC-MS) and $\beta$-secretase inhibitor also is a new tetrapeptide with the sequence Gly-Trp-Trp-Glu. The purified $\beta$-secretase inhibitory peptide inhibited $\beta$-secretase non-competitively and also show less inhibition on trypsin, however no inhibition on other proteases such as $\alpha$-secretase, chymotrypsin, and elastase.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.05a
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• pp.380-385
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• 2004

The efficiency of complex slurry preparation route for developing the high performance SiC matrix of RS-SiCf/SiC composites has been investigated. The green bodies for RS-SiC materials prior to the infiltration of nw/ten silicon were prepared with various C/SiC complex matrix slurries, which associated with both different sizes of starting SiC particles and blending ratios of starting SiC and carbon particles. The characterization of RS-SiC materials was examined by means of SEM, TEM, EDS and three point bending test. Based on the mechanical property-microstructure correlation, process optimization methodology is also discussed. The flexural strength of RS-SiC materials greatly depended on the content of residual Si. The decrease of starting SiC particle size in the C/SiC complex slurry was effective for improving the flexural strength of RS-SiC materials.

• Journal of Surface Science and Engineering
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• v.48 no.2
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• pp.56-61
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• 2015

In this study, the wear performance of manganese phosphate coating on SM45C with addition agent of Tartaric acid and Citric acid were investigated. The Surface morphology of manganese phosphate coating was examined by Scanning Electron Microscope (SEM) and Energy Dispersive X-ray spectroscopy (EDS). It is found that Mn, P, Fe, O and C. The crystal structure and thee composition was analysis and determined by using XRD. The XRD results indicated that manganese phosphate coatings are mainly composed of $(Mn,Fe)_5H_2(PO_4)_44H_2O$ and consists of a lot of close packed lump crystalline. Based on the time dependence of morphology and the weight of manganese phosphate coating, it shows that the phosphating process mainly includes three stages: corrosion of the substrate, creation and growth of phosphate crystal nucleus and thickening of manganese phosphate coating. The wear tests were performed in a ball on disc apparatus as per ASTM G-99 Standard. It was showed that the initial wear was quite high followed by low sludge.

• Journal of Biomedical Engineering Research
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• v.33 no.1
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• pp.32-38
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• 2012

Recently, several ultrasound imaging techniques for tissue characterization have been developed. Among them, ultrasound elastography is regarded as the most promising modality and has been rapidly developed. One of ultrasound elastography techniques is shear modulus imaging. Normal and cancerous tissues show big difference of shear moduli and they have good image contrast. However shear wave elastography requires more complicated hardware and more computations for image reconstruction algorithm. Therefore new efficient techniques are being developed. In this paper, we have developed a very flexible ultrasound system for elastography experiments. The developed system has capabilities to acquire ultrasound RF data of all channels and generate arbitrary ultrasound pulse sequences. It has a huge amount of memories for RF data acquisition and a simple and flexible pulse generator. We have verified the performance of the system showing conventional B-mode images and preliminary results of elastography. The developed system will be used to verify our own reconstruction algorithm and to develop more efficient elastography techniques.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.73.2-73.2
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• 2010

Polymer solar cells (PSCs) have attracted considerable academic and commercial interest because of their unique advantages, such as the facile manufacture of low cost, flexibility, lightweight, and solution processibility. Recently, high-performance polymer solar cells made from a mixture of poly(2,7-carbazole) derivatives, PCDTBT, and [6,6]-phenyl C71 butyric acid methyl ester (PC70BM) have been reported, with maximum power conversion efficiency of 6.1%. In this work, we report new novel copolymers based on poly(2,7-carbazole) derivatives with a suite of electron-deficient moieties or electron-rich units. We systematically investigated the synthesis, thermal stability, as well as the optical and electrochemical properties of these polymers. Detailed synthetic scheme, optical, electrochemical, and photovoltaic properties of the copolymers will be presented.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.10
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• pp.1366-1368
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• 2004

The Mafriwal dairy cattle was developed to meet the demands of the Malaysian dairy Industry. Although there are reports on its production and reproductive performance, there has been no work on its molecular characterization. This study was conducted to characterize the Mafriwal dairy cattle using microsatellite markers. Fifty two microsatellite loci were analysed for forty Mafriwal dairy cows kept at Institut Haiwan Kluang, Malaysia. The study showed two microsatellite loci to be monomorphic. Allele frequencies for the polymorphic loci ranged from 0.01 to 0.31. Genotype frequencies ranged from 0.03 to 0.33. The mean overall heterozygosity was 0.79. All polymorphic microsatellite loci deviated significantly (p<0.01) from Hardy-Weinberg equilibrium. The Mafriwal dairy cattle showed high genetic variability despite being a nucleus herd and artificial insemination being practiced.

• Proceedings of the IEEK Conference
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• 2000.06b
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• pp.96-99
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• 2000

We presents a BGA(Ball Grid Array) package for RF circuit modules and extracted its electrical parameters. We constructed a BGA package of ITS(Intelligent Transportation System) RF module and examined electrical parameters with a HP5475A TDR(Time Domain Reflectometry) equipment and compared its electrical parasitic parameters with PCB RF circuits. With a BGA substrate of 3 $\times$ 3 input and output terminals, we have found that self capacitance of BGA solder ball is 68.6fF, self inductance 146pH, mutual capacitance 10.9fF and mutual inductance 16.9pH. S parameter measurement with a HP4396B Network Analyzer showed the resonance frequency of 1.55㎓ and the loss of 0.26dB. Thus, we may improve electrical performance when we use BGA package structures in the design of RF circuit modules.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.9
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• pp.19-24
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• 2004

In this paper, we have demonstrated the fabrication of a 70 nm foot print of the T-gate by using a positive resist ZEP520/P(MMA-MAA)/PMMA trilayer by double exposure method without a thin dielectric supporting layer on the substrate. The device performance was characterized by DC and RF measurement. The fabricated 70 nm InGaAs/InAlAs MHEMTS with 70 ${\mu}{\textrm}{m}$ unit gate width and 2 fingers showed good DC and RF characteristics of Idss, max =228.6 mA/mm, gm =645 mS/mm, and fT =255 GHz, respectively.