• Natural Product Sciences
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• v.15 no.2
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• pp.90-95
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• 2009

Phytochemical investigation of the MeOH extract of the leaves of Nelumbo nucifera resulted in the isolation of five norsesquiterpenes, four flavonoids, two triterpenes and one alkaloid. Their chemical structures were characterized by spectroscopic methods to be (E)-3-hydroxymegastigm-7-en-9-one (1), (3S,5R,6S,7E)- megastigma-7-ene-3,5,6,9-tetrol (2), dendranthemoside B (3), icariside $B_2$ (4), sedumoside $F_1$ (5), luteolin (6), quercetin 3-0-${\beta}$-D-glucuronide (7), quercetin 3-0-${\beta}$-D-glucoside (8), isorhamnetin 3-0-rutinoside (9), alphitolic acid (10), maslinic acid (11), and N-methylasimilobine (12). Norsesquiterpenoids (1-5) and triterpenes (10-11) were isolated for the first time from this plant. Compounds 6 and 10-12 exhibited considerable cytotoxicity against four human cancer cell lines in vitro using a SRB bioassay.

• Archives of Pharmacal Research
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• v.28 no.10
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• pp.1142-1146
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• 2005

Seven sesquiterpene lactones were isolated by the chromatographic separation of the MeOH extract of the aerial parts of Saussurea calcicola (Compositae). Their structures were determined spectroscopically to be cynaropicrin (1), arguerin B (2), cebellin F (3), 8${\alpha}$-hydroxy-11${\alpha}$, 13-dihydrozaluzanin C (4), desacylcynaropicrin (5), 3${\beta}$-hydroxy-8${\alpha}$-epoxymethylacriloiloxy-4(15), 10(14), 11(13)-trien-guaian-6, 12-olide (6), and kandavanolide (7). Compounds 1 and 2 showed significant cytotoxicity against five cultured human tumor cell lines with $ED_{50}$ values ranging from $0.23{\~}1.72\;{\mu}g/mL$.

• The Journal of Information Technology
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• v.10 no.4
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• pp.1-10
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• 2007

The C.B.D(Central Business District), called the central place of the urban area, is core of the city. It is consists of variety services. This study is aimed at analyzing the land use of the C.B.D. in Daejeon. Deajeon Metropolitan City site $36^{\circ}11'{\sim}36^{\circ}30'N,\;127^{\circ}15'{\sim}127^{\circ}34'E$. The field survey area is JoongAng-ro neighboring area, partial EunHaing-dong. The results are as follows: First, The land use of surveyed area is concentrate on variety services, because of excellent accessibility. Second, The land use of ground floor(Fl) and second floor(F2) has services for the customers convenience to approach. Third, The land use of surveyed area has undergone a lot of changes over the last three years(2004. 11~2007. 11.)

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.11a
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• pp.97-100
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• 2009

Fire resistance properties and mechanical properties of high strength concrete mock-up column using organic fiber by KS F 2257 Methods of fire resistance test for elements of building construction and compression test was investigated for application of precast concrete column method of high rise building in this study. As a test result, it was appeared that ECC permanent form is available as fire resistance method of high strength concrete and new precast concrete construction method for facilitating construction of high rise building.

• Proceedings of the Korea Society for Simulation Conference
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• 2005.11a
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• pp.138-143
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• 2005

In order to reduce traffic accident, the interaction between drivers and roads should be studied in drivers' behaviour standpoints, and then this must be applied to the establishment of the road design standard. The K-ROADS(KICT-Road Analysis Driving Simulator) was developed to analyze and evaluate the road safety at the project HuRoSAS(Human & Road Safety Analysis System), since 2003. This has two distinct functions. One is the visual system which has 360 degree F.O.V. to reduce a dead angle on black spots as at-grade intersection. The other is the motion system which reproduce high frequency vibration made in irregular road surface and vehicle's motion. The K-ROADS has been used the study on the effect of alternatives of speed hump, and the study on the interior wall design of long tunnel to safety standpoints.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.296-299
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• 2008

최근 통신시스템과 핸드폰, PDA등의 통신기기들의 발전에 따라 사용자들은 높은 데이터 전송률과 고속의 통신서비스를 요구하고 있다. 이러한 상황에서 유 무선 통합 시스템인 Radio-over-Fiber(RoF) 시스템은 그 대안으로 대두되고 있다. 본 논문에서는 광전자소자를 선 왜곡 방식에 적용하여 광 송신기의 선형성을 향상시키는 방법을 제안하였다. 선 왜곡 방식은 두 개의 루프로 구성되어 있으며, 광 부품인 레이저 다이오드와 포토 다이오드 그리고 RF 부품인 위상변위기, 감쇄기, RF 결합/분배기, RF 증폭기를 사용하였다. 메인 루프에서 주 레이저 다이오드의 비선형성에 의해 발생된 왜곡신호성분은 보조 루프에서 부 레이저 다이오드를 이용하여 추출된 선 왜곡신호에 의해서 제거된다. 제안된 선형화 기법을 적용하여 2.4 GHz에서 선형화 기법을 적용하기 전보다 3차 상호변조 왜곡성분이 약 30dB 향상된 결과를 얻었다.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.701-703
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• 1993

This paper describes characteristic analysis of high frequency inverter using zero voltage switching(ZVS) which is one of the methods to reduce switching loss. This study is generally described by introducing normalized control variables. Moreover, many characteristics of analysis results offer importanat data for circuit design. In addition, the result of its characteristic analysis is compared with that from PSpice's simulation.

• Journal of Korean Society on Water Environment
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• v.21 no.3
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• pp.289-296
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• 2005

Purpose of this research is to quantitatively and qualitatively investigate the blow down wastewater produced from Yeosu Industrial Complex. Approximately, 38,325,000 tons/year of wastewater is produced, processed and finally discharged. Six representative companies, namely, A, B, C, D, E, F were chosen for this study. Each company produce over 5,000 tons/day of wastewater. In total, 6,844 tons/day of blow down water is produced from these six companies, put together. However, companies A and C produce about 24% and 37% of blow down water, respectively. It was found that the blow down water had favorable qualities, except for its high conductivity, ranging from 230 to $1,700{\mu}s/cm$. It was evident that, this water can be suitable for reuse, for industrial purposes, if a suitable treatment, for example, RO membrane process is adopted to remove high conductivity.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.12
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• pp.929-934
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• 2002

This paper considers the vibration Problem of vehicle driveline which consists of two propeller shafts and the center bearing. The excessive vibration occurs at the center bearing when the vehicle starts to run. Using the kinematic constraints at the universal joint between two propeller shafts, we developed an one d.o.f model which describes the radial motion of the center bearing. We found out that the vibration occurs at the specific vehicle speed corresponding to the natural frequency of the model. Comparing the simulation results with test results we also show that the vibration at low vehicle speed is caused primarily by the feint angle and secondarily by the mis-aligned yoke flange rather than by the unbalance.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.2
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• pp.3-9
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• 2016

In this paper, we propose a Radio over Fiber system for small cell applications and for mobile fronthaul networks supporting cloud-radio access networks(RAN). We built a system with a downlink employing orthogonal frequency division multiplexing (OFDM) techniques and an uplink using single carrier-frequency multiple access(SC-FDMA). System parameters are evaluated for various subcarrier modulations and the results of link performance measurements are analyzed.