• Journal of electromagnetic engineering and science
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• v.10 no.1
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• pp.28-34
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• 2010

This paper introduces a new U.S. ultra-wideband(UWB: 3.1~10.6 GHz) 1:2 power divider based on a single section Wilkinson type configuration. The divider provides very flat in-band power splitting, high isolation, low insertion loss, sharp roll-off bandpass filtering, and DC blocking characteristics. The circuit consists of a $\lambda$/4 Y resonator, three capacitively coupled $\lambda$/2 short-circuited lines, and a resistor between the two output ports. The circuit structure was simulated with ADS and HFSS, and realized with low-temperature co-fired ceramic(LTCC) green tape, which has a dielectric constant of 7.8. $|S_{11}|$ better than 10 dB, $|S_{21}|$ and $|S_{31}|$ less than 3.2 dB, with both $|S_{22}|$ and $|S_{32}|$ measured as better than 12 dB for the whole UWB band. Measurement results agree closely with HFSS simulation results. The power divider has a compact size of $4\times9\times0.6mm^3$.

• The Journal of the Korea institute of electronic communication sciences
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• v.3 no.3
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• pp.153-157
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• 2008

The MCS(Micro-coplanar strip) line has been analyzed. The conformal mapping method is used to calculate the quasi-static effective permittivity and characteristic impedance of this MCS line. The computed results of the present work are found to be in good agreement when compared with the results obtained using commercial S/W, IE3D. And in this paper, the stepped-impedance low pass microstrip filter is designed and fabricated with MCS lines for improving the frequency responses. The LPF proposed structure has been also designed and implemented to have the sharp attenuation characteristics in stop band. The agreement between simulation and measurement results verify the implemented LPF.

• Korean Journal of Medicinal Crop Science
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• v.7 no.2
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• pp.143-146
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• 1999

The cytotoxicity-guided fractionation of the seed of Plantago asiatica extracts led to the isolation of four compounds, responsible for the cytotoxicity against four human tumor cell lines, i. e., A431 (Human Epidermoid carcinoma), KHOS-NP (Human Osteosarcoma). SNU-1 (Human stomach carcinoma), SNU-C4 (Human large intestine carcinoma). The structure were elucidated by the phsyco chemical data: ${\beta}-sitosterol(C1)$, $cholest-5-en-3{\beta}-ol(C2)$, rutin(C3), $coumarin-7-O-{\beta}-glucopyranoside(C4)$. $IC_{50}$ values of compound C2 were 14.6, 13.5, 10.3, 17.8 ${\mu}g/ml$, and compound C3 and C4 showed activity, having $IC_{50}$ values ranging from 10.3 to 20.14 ${\mu}g/ml$.

• Journal of Microbiology and Biotechnology
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• v.22 no.11
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• pp.1482-1485
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• 2012

A natural furan derivative was isolated from the methanolic extract of the fruit bodies of Fomitiporia ellipsoidea. Its chemical structure was elucidated as methyl 3,5-dioxo-1,3,5,7-tetrahydrobenzo[1,2-c:4,5-c']difuran-4-carboxylate by means of extensive NMR and MS data analysis, and named as fomitiporiaester A (1). Compound 1 showed significant antitumor activity to hepatoma $H_{22}$ in vivo, and the inhibition rates were 42.94%, 49.17%, and 58.15% at concentrations of 5, 10, and 20 mg/kg, respectively. Compound 1 showed weak cytotoxic activities against the human hepatoblastoma (HepG-2) and human oophoroma (Skov 3) cell lines with$IC_{50}$ values of more than $100{\mu}M$.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.1
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• pp.219-224
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• 2019

Textbooks with a lot of numerical information, such as the year, need to apply the mnemonic system. The mnemonic-system in numbers are used in many ways, such as dots, lines, and bars, and information images serve as symbols to help memory. The memory structure of the brain is more efficient in providing more information than just numbers. Previous studies have suggested graphical or arrayed image algorithms for mobile environments. In this study, we would like to link additional information related to figures with original data by selecting a subject with a lot of numerical information. We propose unique processes in mobile environments and evaluate the numerical algorithms to link meaning.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.545-552
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• 2008

It becomes to make its necessity of getting more closer approach for the design and the detailed analysis of implementation method and study with respect that the plan is put into shape for the interconnection between Seoul Line No.9 and the AREX line which has been on commercial running since it had been opened on March 2007. We introduce the concrete analysis and the rasied problems and a way how to solve as well for the characteristics of interconnection train and signaling 시스템tem structure between two lines in order to design and implement the interconnection running. Also,

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.3
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• pp.449-461
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• 2017

The uncertain existence and insufficient information of underground structures, such as pipe lines and cable tunnels, is causing many problems related to route plan, design, construction of new underground structures. The theoretical equations that is able to predict the location, size, and direction of underground structures through electric field analysis are suggested at the previous study (Ryu., 2015). Three field tests were performed for predicting the location, size, and direction of underground structures and the existence and size of sink-hole. Prediction results were reflected at the design and follow-up measures were performed.

• Korean Journal of Pharmacognosy
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• v.36 no.3 s.142
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• pp.195-200
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• 2005

Smilacis Chinae Radix is root of Smilax china L.. It has been known as a korean folk medicine for anti-inflammatory, anti-microbial diuresis, detoxification and relieving enteropathy as diarrhea. Reactive oxygen species(ROS) are continuously produced at a high rate as a by-product obtained in the aerobic metabolism. A major portion of living organisms has defense system as superoxide dismutase or catalase against damage produced by ROS. Several lines of evidence provided that ROS appears to cause to develop aging and various diseases. In this study, we have investigated the antioxidant activities of Smilacis Chinae Radix in order to screen the antioxidant substances from natural products. As a result, EtOAc extract of Smilacis Chinae Radix exhibited potent antioxidant effect on various antioxidant experiment. The major components of antioxidant activity were isolated from EtOAc extract of Smilacis Chinae Radix. Their structure of compounds were identified as quercetin and (-)-epicatechin by spectroscopic evidence, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.8
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• pp.701-708
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• 2016

A new design for an ultra-wideband microstrip-to-FGCPW(Finite Ground Coplanar Waveguide) transition is presented. The proposed transition provides the electric field and impedance matching between adjacent transmission lines by ground shaping. The transition is designed on the analytical expressions of whole transitional structure. Conformal mapping is applied to obtain the characteristic impedance of FGCPW with bottom aperture within 3.3 % accuracy as compared with the EM-simulation results. As design example, the fabricated transition in back-to-back configuration provides insertion loss less than 1 dB per transition and return loss better than 10 dB for frequencies from 9 GHz to over 40 GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.5
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• pp.436-444
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• 2002

This paper presents a new method, which uses defected ground structure (DGS) on the ground planes of planar transmission lines such as microstrip and coplanar waveguide (CPW), to reduce the size of amplifiers. The main idea can be summarized as follow; DGS on the ground plane of microstrip or CPW line shows an increased slow-wave effect due to the additional equivalent L-C components. So the electrical length of the transmission line with DGS is longer than that of the standard transmission line for the same physical length. Then, the length of the transmission line with DGS can be shortened in order to maintain the original electrical length to be the same. This leads the matching of the original amplifier to be kept. In order to show the proposed method is valid, two kinds of amplifiers, the original amplifier and reduced amplifier, are fabricated, measured, and compared using both microstrip and CPW. The measured performances of the reduced amplifiers with DGS are quite similar to the ones of the original amplifiers for both microstrip and CPW amplifiers, even though the size of matching networks of the amplifiers with DGS are much smaller than those of the original amplifiers.