• ETRI Journal
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• v.27 no.5
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• pp.579-584
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• 2005

A CMOS direct-conversion mixer with a single transistor-level topology is proposed in this paper. Since the single transistor-level topology needs smaller supply voltage than the conventional Gilbert-cell topology, the proposed mixer structure is suitable for a low power and highly integrated RF system-on-a-chip (SoC). The proposed direct-conversion mixer is designed for the multi-band ultra-wideband (UWB) system covering from 3 to 7 GHz. The conversion gain and input P1dB of the mixer are about 3 dB and -10 dBm, respectively, with multi-band RF signals. The mixer consumes 4.3 mA under a 1.8 V supply voltage.

• Korean Journal of Materials Research
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• v.17 no.1
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• pp.1-5
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• 2007

GaN thin fan were grown by spin coated colloidal GaOOH precursor. Polycrystalline GaNs with crystalline size of $10{\sim}100nm$ were grown on $SiO_2$ substrate. The shape of crystallite above $900^{\circ}C$ had the hexagonal plate and column type. X-ray diffraction patterns for them correspond to those of the hexagonal wurtzite GaN. With increasing droplets. i.e, thickness of deposited layers, XRD intensity increased. PL (photoluminescence) spectrum consisted with an weak near band-edge emission at 3.45 eV and a broad donor-acceptor emission band at 3.32 eV. From the low temperature PL measurement on GaN grown at $800^{\circ}C$ that the shallow donor-acceptor recombination induced emission was more intense than the near band-edge excitonic emission.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.8
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• pp.713-718
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• 2013

In this paper, additional data transmission scheme was proposed based on SSB-OFDM Communication system which was know as efficient technique for bandwidth, because it used only single side band instead of double side band. When sending additional data which should be well spreaded for low power characteristics and error robustness. Gold code was selected for spreading code because it has excellent low-cross correlation characteristics. Through computer simulation, the validity was proved that proposed system is well worked with SSB-OFDM system.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.813-815
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• 1992

Accurate Capacitance-Voltage characteristics of Metal-Insulator-Semiconductor (MIS) devices in narrow band-gap semiconductors are presented. The unique band structure of narrow band-gap semiconductors is taken into account such as non-parabolicity and degeneracy. Compensated and partially ionized impurities either in the bulk or the space charge region are also considered. HgCdTe is a defect semiconductor, so this approach is very important for characterization and analysis of MIS devices.

• The KIPS Transactions:PartC
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• v.8C no.4
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• pp.443-450
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• 2001

본 논문에서는 무선 ATM 망에서 VBR(Variable Bit Rate) 트래픽의 QoS(Quality of Service)를 보장하고 무선 채널의 효율성을 극대화 할 수 있는 새로운 동적 슬롯 할당 알고리즘인 NDSA(Neural Dynamic Slot Assignment)를 제안한다. 제안된 알고리즘에서는 ATM 셀 헤더 부분의 GFC(Generic Flow Control) 필드 상에 단말기의 버퍼 상태와 셀 발생률 변화를 부호화 하여 piggybacking 하는 in-band 방식을 채택하였으며 다음 프레임에 할당할 슬롯의 갯수를 기존 방식과는 달리 신경회로망을 이용하여 유동적으로 조절하여 할당함으로써 단말기의 셀 손실이나 지연에 대한 QoS를 보장하고 채널 이용 효율을 높일 수 있었다. 제안된 알고리즘은 BONeS tool을 이용한 시뮬레이션을 통하여 기존의 방식과 비교 분석한 결과 그 정당성을 확인하였다.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.653-655
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• 1997

In this paper, a monoblock dielectric filter for 900MHz band CT-1 is designed by using CAD(Computer Aided Design). Equivalent circuit for monoblock dielectric filter represented by parallel coupled stripline is simulated by using SuperCompact software tool. A Designed filter structure is simulated by using HFSS to optimize result.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2000.11a
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• pp.85-87
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• 2000

To obtain the genetic information of Korean native livestock, the karyotyping of Korean native chick were performed by high-resolution banding technique. The chromosomes were prepared from lymphocyte culture and early embryos with 200 Korean native chick which have been raised at National Livestock Research Institute. There were no significant difference between Korean native chick and Leghorn in the number of chromosomes and chromosomal morphological pattern. Using high resolution banding technique, the yield of G-bands of prophase is much greater than that can be obtained by International System for Standardzed Avian Karyotypes(ISSAK, 1999). The G-band landmarks of Korean native chick were similar to those of ISSAK and Leghorn except some macrochromosomes. chromosome Z and 3 had C-band variants with heteromorphic patterns on distal and centromeric site. The proportion of constitutive heterochromatin, the heterochromatin ratio of Korean native chick was significantly more than that of Leghorn in all chromosomes.

• Journal of Plant Biology
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• v.21 no.1_4
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• pp.29-32
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• 1978

The karyotype of Lilium cernum has been analysed by means of C-banding technique. Most of clones observed were 2n=24 chromosomes which consist of two pairs of submetacentric and ten pairs of subtelocentric chromosomes, among which two pairs of chromosomes(B and E) showed secondary constriction in the short arm. In addition to these chromosomes a small supernumerary telocentric chromosome was seen in the eight clones. Sixtyeight bands were observed in the twentytwo chromosomes of complement and one band in the supernumerary chromosome. A pair of chromosome (L) did not show any band. The bnads on the chromosome. A pair of chromosome (L) did not show any band. The bands on the chromosomes were distributed in the centromere, secondary constriction and intercalary regions of arms. Of the twelve pairs of chromosomes ten pairs showed symmetric banding patterns in each, but two pairs (I and K) showed asymmetric banding patterns.

• Journal of the Korean Chemical Society
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• v.7 no.3
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• pp.197-202
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• 1963

The ${\alpha}-and\;{\beta}$-isomer of 4-nitroazoxybenzenes have been separated by liquid chromatography and their U.V. spectra were examined. The n${\to}{\pi}^{\ast}$ transition band of the compounds did not appear, likewise the cases of other compounds of the series. Transition band of the new isomer were as usual as those of other azoxy-compounds, whereas the ${\pi}{\to}{\pi}^{\ast}$ transition band of the other isomer which is reported in the literature shown peculier hypochromic shift and hypochromic effect. From the spectroscopic point of view it is very likely that the new isomer (m.p. $184-5^{\circ}C$) is ${\alpha}$-isomer and the other one (m.p. $152^{circ}C$) is ${\beta}$-isomer contrary to the literature.

• Bulletin of the Korean Chemical Society
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• v.23 no.10
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• pp.1404-1408
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• 2002

The resonance Raman spectra of trans-polyacetylene films doped heavily with electron donor (Na) and acceptor (HClO4) have been measured with excitation wavelengths between 488- and 1320-nm, and the relationships between the Raman excitation photon energies (2.54-0.94 eV) and its wavenumbers were discussed. We found the linear dependence of the Raman shifts with the exchanges of excitation photon energies. In particular, the Raman wavenumbers in the C=C stretching $(V_1$ band) showed a dramatic decrease with the increase in Raman excitation photon energies. In the case of acceptor doping, its change is larger than that of donor doping. The observed wavenumber (1255-1267 $cm^{-1}$) of the $V_2$ band (CC stretch) of Na-doped form is lower than that of the corresponding band (1290-1292 $cm^{-1}$) of its pristine trans-polyacetylene, whereas the contrary is the case for the HClO4 doped form (1295-1300 $cm^{-1}$). The origin of doping-induced Raman bands is discussed in terms of negative and positive polarons.