• Journal of the Korean Ceramic Society
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• v.30 no.2
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• pp.123-130
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• 1993

Dispersed type Al2O3-SiC composite powders were synthesized from Al-isopropoxide (Al(i-OC3H7)3) and Si(OC2H5)4 precursors by hydrolysis of mixed alkoxides and carbothermal reaction method. The characteristics of the synthesized (dispersed type) Al2O3-SiC composite powders were investigated using XRD, SEM, TEM, BET and particle size analyzer. Carbothermal reaction to produce Al2O3-SiC composite was completed in 10h at 135$0^{\circ}C$ on 3~4㎤/s (0.21~0.28cm/s) of H2 flow rate and about 1/1 of carbon/oxides(=SiO2＋Al2O3) molar ratio. The synthesized powders were observed to have the mean particle size range of 0.4~1.26${\mu}{\textrm}{m}$ and showed finer particle size with increasing SiC content.

• Journal of the Korean Ceramic Society
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• v.33 no.11
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• pp.1276-1284
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• 1996

Ultrafine calcim carbonate powders with the size of 0.05~0.1 ${\mu}{\textrm}{m}$ and the calcite phase were prepared by the nozzle spouting method which was conducted by spouting calcium hydroxide slurry in reactor filled with CO2 gas. Well dispersed ultra-fine particles were synthesized in condition of high Ca(OH)2 concentration of the slurry ( 0.5wt%) synthesized calcium carbonate powder was shown the large particle size with agglo-meration.

• Proceedings of the KIEE Conference
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• 1998.07d
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• pp.1514-1515
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• 1998

Diamond thin films were deposited on n-type (100) Si wafers from $H_2-CH_4$ gas mixture by rf PACVD. Prior to deposition, mechanical scratching was done to improve density of nucleation sites with diamond paste of 3${\mu}m$. The microstructure of deposited diamond thin films was studied by using the following conditions : discharge power of 500W, $H_2$ flow rate of 50sccm, reaction pressure of 20torr, and $CH_4/H_2$ ratio of 0.3$\sim$1%. The deposited diamond thin films showed that the crystallite was increased at the lower methane concentration. The deposited thin films were characterized by Scanning Electron Microscopy. Raman Spectroscopy and Fourier-Transform Infrared Spectroscopy.

• Proceedings of the IEEK Conference
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• 2000.11b
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• pp.349-352
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• 2000

In this paper, a SIMD 64bit MAC (Multiply -Accumulate) unit is designed. It is composed of two 32bit MAC unit which supports SIMD 16bit operations. As a result, It can process two 32bit MAC operations or four 16bit operations in one cycle. Proposed MAC unit is described in Verilog HDL. After functional verification is performed, MAC unit is synthesized and optimized with 0.35$\mu\textrm{m}$ standard cell library. The synthesis result shows that this MAC unit can operate at 80㎒ of clock frequency in 85$^{\circ}C$, 3.0V, worst case process and 125㎒ of clock frequency at 25$^{\circ}C$, 3.3V, typical case process. It achieves 320Mops of performance, and is suitable for embedded DSP processors.

• ETRI Journal
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• v.24 no.5
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• pp.391-397
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• 2002

This paper presents digital signal processor (DSP) instructions and their data processing unit (DPU) architecture for high-speed fast Fourier transforms (FFTs) in orthogonal frequency division multiplexing (OFDM) systems. The proposed instructions jointly perform new operation flows that are more efficient than the operation flow of the multiply and accumulate (MAC) instruction on which existing DSP chips heavily depend. We further propose a DPU architecture that fully supports the instructions and show that the architecture is two times faster than existing DSP chips for FFTs. We simulated the proposed model with a Verilog HDL, performed a logic synthesis using the 0.35 ${\mu}m$ standard cell library, and then verified the functions thoroughly.

• Journal of the Korean Chemical Society
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• v.25 no.3
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• pp.177-182
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• 1981

Benzoylpyridinium and lutidinium salts containing$ [MoO(NCS)_5]^{2-}$ have been synthesized. The complexes have been characterized by spectroscopic, magnetic susceptibility and conductivity studies. Benzoylpyridinium and lutidinium oxopentaisothiocyanatomolybdates(Ⅴ) arise from d-d and charge transfer transitions. The magnetic moments of the complexes are close to the spin-only values. The complex anions are mononuclear containing N-bonded $NCS^-$ ligand.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.7
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• pp.848-854
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• 1999

In this paper, we designed and implemented a precise pulse motor controller chip that generates the pulse needed to control step motor, DC servo and AC servo motors. This chip generates maximum pulse output rate of 5Mpps and has the quasi-S driving capability and speed and moving distance override capability during driving. We designed this chip with VHDL and executed a logic simulation and synthesis using Synopsys tool. The pre-layout simulation and post-layout simulation was executed by Compass tool. This chip was produced with 100 pins, PQFP package by 0.8${\mu}{\textrm}{m}$ gate array process and implemented by completely digital logic. We developed the test hardware board of performance and the CAMC(Computer Aided Motor Controller) Agent softwate to test the performance of the pulse motor controller chip produced. CAMC Agent enables user to set parameters needed to control motor with easy GUI(Graphic User Interface) environment and to display the output response of motor graphically.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.35C no.1
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• pp.15-24
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• 1998

This paper proposes a new template matching algorithm and its chip design. The CC and SAD algorithms require the massive amount of computation. Hence, several algorithms using quantization schemes have been proposed to reduce the amount of computation and its hardware cost. the proposed algorithm called the EMPPM improves at least 22% of the noise margin compared with the MPPM algorithm. In addition, the proposed architecture can reduce the gate count by more than 60% of that used in the SAD algorithm without usig quantization schemes and 28% of the MPPM algorithm. The VHDL models have been simulated by using the CADANCETEX>$^{TM}$ and logic synthesis has been performed by using the SYNOPSYSTEX>$^{TM}$ with $0.6\mu\textrm{m}$ SOG(sea-of-gate) cell library. The implemented chip consists of 35,829 gates, operates at 100 MHz (worst case 53 MHz) and performs the template maching with the speed of 200 Mpixels/sec.

• Bulletin of the Korean Chemical Society
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• v.26 no.3
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• pp.447-450
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• 2005

The crude methanol extract of the fruits of Amomum tsao-ko (Zingiberaceae) showed cytotoxic activity. Bioactivity-guided separation led to the isolation of a diarylheptanoid, tsaokoarylone [7-(4-hydroxy-3-methoxyphenyl)-1-(4-hydroxyphenyl)-hepta-4E,6E-dien-3-one] (2). 2 showed cytotoxicity at 4.9 and 11.4 $\mu$g/mL ($IC_{50}$) against human nonsmall cell lung cancer A549 and human melanoma SK-Mel-2, respectively, determined by SRB colorimetric method. During purification-(4-hydroxyphenyl)-4-hydroxyhexan-2-one (4) together with three known diarylheptanoids was also isolated. Their structures were determined from interpretation of spectroscopic data (IR, UV, MS, and NMR) and synthesis confirmed the structure of 2.

• Bulletin of the Korean Chemical Society
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• v.35 no.7
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• pp.2038-2042
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• 2014

4-(tert-Octyl)phenol derivatives bearing the D-mannitol substructure (6a, 6b, 7) were prepared from $\small{D}$-mannitol and evaluated their anticancer activity against human lung (A549) and prostate (Lncap, Du145, PC3) cancer cell lines. Among derivatives tested, the bis(tert-octyl)phenoxy compound 7 exhibited strongest proliferation inhibitory activities against human cancer cell lines tested, especially high sensitivity to human Du145 prostate cancer cells ($IC_{50}=7.3{\mu}M$).