• 한국응용과학기술학회지
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• 제11권1호
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• pp.79-85
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• 1994

All the activities and physical properties including surface tension' foaming power, foam stability, emulsifying power, dispersion effect of 3-(N, N-dimethyl N-alkylammonio)-2-hydroxyY-1-propane sulfonate (HSB)류와 3-CN-alkylamidopropyl-N,N-dimethylamm-onjo)-2-hydroxy-1-propane sulfonate (APSB) aquous solution were measured and critical micelle concentration was evaluated. Their cmc of hydroxy sulfobetaine derivatives evaluated by the surface tension method was $1.0{\times}10^{-3}{\sim}1.0{\times}10^{-4}$ mol/l, and surface tension of the aquous solution was decreased to $27{\sim}38dyne/cm$. The experimental results for foaming power, foam stability, emulsifying power in liquid paraffin showed a good surface active properties, especially, dispersion effect in ferric oxide exhibited some efficient surface active properties, and then it would be expected to application as detergent and dispersion agent.

• 전자공학회논문지A
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• 제30A권12호
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• pp.98-107
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• 1993

This paper describes a design of a multi-bit oversampling noise-shaping D/A converter which achieves a resolution of 12 bits using oversampling technique. In the architecture the essential block which determines the whole accuracy is the analog internal D/A converter, and the designed charge-integration internal D/A converter adopts a differential structure in order to minimize the reduction of the resolution due to process variation. As the proposed circuit is driven by signal clocks which contains the information of the data variation from the noise-shaping coder, it minimizes the disadvantage of a charge-integration circuit in the time axis. In order to verify the circuit, it was integrated with the active area of 950$\times$650${\mu}m^{2}$ in a double metal 1.5-$\mu$m CMOS process, and testified that it can achieve a S/N ratio of 75 dB and a S/(N+D) ratio of 60 dB for the signal bandwidth of 9.6 kHz by the measurement with a spectrum analyzer.

• 대한전자공학회논문지
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• 제9권5호
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• pp.27-33
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• 1972

This paper describes the computer-aided design, fabrication and performance of high Q and high gain active filters suitable for microminiaturization in the frequency range of 10-800MHz, based on the negative resistance operation of a transistor. 48 as high as 1000 and a transducer gain as high as 35dB can readily be obtained with a single-transistor amplifier and with an inductance as small as a few nH at higher frequencies and 150 nH at lower frequencies in tile above frequency range. The gain of the proposed active filter can be stoabilized within $\pm$ 1.5 dB over the temperature range -1$0^{\circ}C$ to +5$0^{\circ}C$ and the temperature dependence of the center frequency is tapicalla 50ppm/$^{\circ}C$. An experimental FM receiver utilizing these fitters and operating at a carrier frequency of 92 MH3 was built. The whole circuit was fabricated on eight alumina substrates of by the thick-film hybrid IC technique and the coils are constructed, for miniaturization, in a spiral form of 3 or 4 turns of enamel copper wire with an overall diameter of about 5mm. The test results are also reported in this paper.

• Archives of Pharmacal Research
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• 제19권4호
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• pp.312-316
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• 1996

A series of N-Cbz${alpha}$-aminosucinimides (1), combining common moieties of various anticonvulsants such as N-CO-C-N and cyclic imide in a single molecule, were synthesized from the corresponding (R)- and (S)-N-Cbz-aspartic acid (2). And their in vivo anticonvulsant evaluations in MES and PTZ test were investigated. And also the rotorod test for neurotoxicity was investigated. All the tested compounds (1), except 1c and 1f, showed significant anticonvulsant activities in both MES and PTZ test. And the most active compound among them in MES test was (R)-N-Cbz-${alpha}$-amino-N-methylsuccinimide (1b) $(ED_50/=52.5 mg/kg)$ and (S)-N-Cbz-aminosuccinimide((1d) was most active in PTZ test $(ED_50/=78.1 mg/kg)$. And the $TD_50$ values of the tested compounds were above 117.5 mg/kg. These pharmacological data were comparable to those of currently available anticonvulsants. And also we found that the pharmacological effects were dependent on their N-substituted alkyl chains and their stereochemistry.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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• pp.781-784
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• 2005

We have developed technology to fabricate large-size active matrix organic light-emitting diode (AMOLED) displays with good color purity. Using these innovations, we have developed a 40inch diagonal WXGA AMOLED full color display. Because the TFT circuitry occupies a large portion of the pixel structure, an efficient white emission OLED is essential to integrate the device onto the active matrix backplane. The development of these technologies enables OLED displays to fulfill the requirements for larger size applications such as HDTVs

• 대한화장품학회지
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• 제35권1호
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• pp.73-78
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• 2009

닭의장풀(Commelina communis L. Dayflower) 추출물의 미백효능을 확인하기 위하여 B16 melanoma 세포를 이용하여 melanin 생성에 관련된 다양한 실험을 실시하였다. 닭의장풀 추출물은 버섯 tyrosinase 활성 실험에서 저해 효과를 보이지 않았으나, melanin 생성 저해효과를 나타내었다. B16-F10 멜라노마 세포를 이용한 활성시험 결과에서, 닭의장풀 추출물은 1,000 ${\mu}g/mL$의 농도에서 약 32%의 멜라닌 생성을 억제하였으며, 세포내 티로시나제 활성 억제 능도 우수하여 닭의장풀 추출물 250 ${\mu}/mL$ 이상의 농도에서 50% 이상의 저해 효과를 보였다. 추출물의 생성 기작에 대한 영향을 조사한 결과, melanin 합성의 key protein 인 tyrosinase 발현의 우수한 저해 능력을 보였고, tyrosinase related protein-1 (TRP-1)의 발현 억제와 tyrosinase related protein-2 (TRP-2)의 N-glycosylatin 억제를 통해 melanin 합성이 억제되는 것으로 분석되었다. 따라서 닭의장풀 추출물은 melanin 합성에 필수적인 효소(tyrosinase, TRP-1)의 발현 저해 및 TRP-2의 N-glycosylation 억제를 통해 미백 효과를 나타내는 것으로 확인되었으며, 이에 따라 본 추출물은 melanin 합성의 효소 경로를 저해하는 미백 소재로 활용할 수 있을 것으로 사료된다.

• 전자공학회논문지D
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• 제35D권4호
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• pp.1-8
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• 1998

An MMIC single-balanced upconverting mixer for PCS application has been successfully developed using an MMIC process employed by 1 .mu. ion implanted GaAs MESFET and passive lumped elements consisting of spiral inductor, Si3N4 MIM capacitors and NiCr resistors. The configuration of the mixer presented in this paper is two balanced cascode FET mixers with common-source self-bias circuits for single power supply operation. The dimension of the fabricated circuit including two active baluns intermodulation characteristic with two-tone excitation are also measured, showing -28.17 dBc at IF power of -30 dBm.

• Applied Biological Chemistry
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• 제42권2호
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• pp.170-175
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• 1999

국내 식물자원으로부터 천연 항산화물질을 탐색하기 위하여 항산화활성이 기대되는 38종의 식물을 MeOH 수용액으로 추출한 후, EtOAc와 물로 분배, 추출하였다. 각 추출물에 대하여 DPPH radical 소거활성을 검정하였고, 이중에 작약을 포함한 13종의 식물에서 활성이 확인되었다. 작약뿌리로부터 항산화물질을 분리하기 위하여 80% MeOH 수용액으로 추출, 농축하였고, 이를 EtOAc, n-BuOH 및 물로 계통분획하였다. 활성이 확인된 n-BuOH과 EtOAc층에 대하여 활성을 추적해가며 column chromatography를 반복하여 3종의 활성물질을 분리하였다. 이들의 화학구조를 NMR 등의 spectral data를 해석하여 (+)-catechin, $1,2,3,4-tetragalloyl-6-digalloyl-{\beta}-D-glucose$ 및 $1,2,3,4,6-pentagalloyl-{\beta}-D-glucose$로 동정하였다.

• 한국미생물·생명공학회지
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• 제34권4호
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• pp.306-310
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• 2006

토양 미생물인 방선균의 배양액으로부터 그람양성균에 대해 항균활성을 가지는 항균성 물질을 탐색하였다. 2,500주의 방선균 배양액을 탐색하여 항균성 물질 생산균주 Streptomyces sp. G9l353을 분리하였고, 그로부터 생산된 항균성 물질인 A91353을 분리 정제하였다. A91353은 다양한 구조해석 연구에 의하여 N-acetyl-phenylalanine으로 동정되었으며 Sc. pyogenes 308A, Sc. pyogenes 77A 등과 같은 그람양성균에 대해 선택적이며, D-alanyl-D-alanine과 상호작용 하여 그람양성균의 세포벽 합성을 저해하는 것으로 사료된다. N-acetyl-phenylalanine의 최소생육저해 농도는 그람양성균에 대해서 $50{\mu}g/ml$ 이었으며, 그람음성균에 대한 활성은 나타나지 않았다.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 1999년도 KOBA 방송기술 워크샵 KOBA Broadcasting Technology Workshop
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• pp.219-226
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• 1999

Recently a study of Virtual-Reality becomes active. Expectation to 3-D reproduction technology rises with it. Electro-holography using Spatial light modulator (SLM) attracts attention, because natural 3-D animated image is provided. In this paper recent development of 3D-TV by Electro-holography is reported. We consider the conditions to holographic TV such as input, transmission and display systems. Also we consider about fast hologram calculation because It is important to execute hologram calculation at high speed to realize the real time electro-holography. Then we consider the possibility of real time holography.