• 전기학회논문지P
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• 제52권4호
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• pp.148-153
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• 2003

In this paper, the low voltage 3V Sigma-Delta Digital Analog Converter(DAC) is designed for using in the transmitter of ADSL analog front-end. We have developed the CMOS DAC according to ANSI T1.413-2(DMT) standard specifications of the chip. The designed 4th-order DAC is composed of three block which are 1-bit DAC, 1st-order Switched-Capacitor filter and analog active 2nd-order Resistor-Capacitor(RC) filter. The HSPICE simulation of the designed DAC showing 65db SNR, is connected with 1.1MHz continuous lowpass filter. And also, we have performed the circuits verification and layout verification(ERC, DRC, LVS) followed by fabrication using TSMC 2-poly 5-metal p-substrate CMOS $0.35{\mu}m$ processing parameter. Finally, the chip testing has been performed and presented in the results.

• Asian-Australasian Journal of Animal Sciences
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• 제23권1호
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• pp.116-121
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• 2010

Long-chain polyunsaturated fatty acids (LC-PUFA) promote the development of brain and vision of the fetus, relieve inflammation, inhibit oral dysplasia of rumor cell, decrease the incidence of cardiovascular disease and regulate arrhythmia. ${\Delta}-6$ desaturase is the rate-limited enzyme in the desaturation process. This study reports the cloning, characterization and tissue expression of a ${\Delta}-6$ desaturase gene in the chicken. PCR primers were designed based on the predicted sequence of chicken ${\Delta}-6$ desaturase (accession number: XM421053) and used to isolate a cDNA fragment of 1,323 bp from chicken liver. Based on the 1,323 bp fragment an EST (BI390105) was obtained by BLAST. The EST and 5'nd of the 1,323 bp fragment were partially overlapped. Gene specific primers derived from the EST were used for amplification of the 5'nd. Another gene-specific primer derived from the 1,323 bp fragment was used for amplification of the 3'nd by 3'ACE. Then the three overlapping cDNA sequences obtained were assembled with DNAMAN software and a full-length ${\Delta}-6$ desaturase of 2,153 bp was obtained. The full-length cDNA contained an ORF of 1,335 bp with a 5'ntranslated region of 147 nucleotides followed by an ATG initiation codon. Stop codon TGA was at position 1,481-1,483 bp. The deduced amino acids shared an homology above 77% with bovine, mice, orangutan, rat and human. The protein sequence had three histidine-rich regions HDFGH (HisI region), HFQHH (HisII region) and HH (HisIII region), a cytochrome $b_{5}$-like domain containing a heme-binding motif and two transmembrane domains. Sequence analysis of the chicken genomic DNA revealed that the coding sequence of chicken ${\Delta}-6$ desaturase included 12 exons and 11 introns. Semi-quantitative RT-PCR showed that the ${\Delta}-6$ desaturase expression levels were in turn liver, spleen, pancreas, lung, breast muscle, heart, and abdominal fat. The expression of ${\Delta}-6$ desaturase in liver was significantly higher than that in breast muscle (p<0.01). The expression of ${\Delta}-6$ desaturase in lung was significantly higher than that in abdominal fat (p<0.01). This is the first clone of chicken ${\Delta}-6$ desaturase.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제38권1호
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• pp.14-19
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• 2012

Introduction: This study was conducted to evaluate ssrA expression resulting from adaptation of Escherichia coli (E. coli) to oral pathogens through signal exchange. Materials and Methods: Human cell lines Hep2 and HT29, wild-type E. coli (WT K-12), ssrA knock-out E. coli (${\Delta}K$-12), and Scleropages aureus (S. aureus) were used. A single culture consisting of Hep2, HT29, WT K-12, and ${\Delta}K$-12, and mixed cultures consisting of Hep2 and WT K-12, Hep2 and ${\Delta}K$-12, WT K-12 and S. aureus, ${\Delta}K$-12 and S. aureus, and Hep2, WT K-12, and S. aureus were prepared. For HT29, a mixed culture was prepared with WT K-12 and with WT K-12 and S. aureus. Total RNA was extracted from each culture with the resulting expression of ssrA, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-${\kappa}B$), and p53 was evaluated by Reverse transcription polymerase chain reaction (RT-PCR). Results: The expression of ssrA in a single culture of WT K-12 was lower than that observed in the mixed culture of WT K-12 with S. aureus. Greater ssrA expression was observed in the mixed culture of WT K-12 with Hep2 than in the single culture of WT K-12. The expression of NF-${\kappa}B$ was higher in the mixed culture of Hep2 with ${\Delta}K$-12 than that in the mixed culture of Hep2 with WT K-12, and was lowest in the single culture of Hep2. The expression of ssrA was higher in the mixed culture of WT K-12 with Hep2 and S. aureus than in the mixed culture of WT K-12 with Hep2. Conclusion: These results suggest that ssrA plays an important role in the mechanism of E. coli adaptation to a new environment.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.627-628
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• 2006

A low-voltage switched-capacitor $2^{nd}$-order $\Sigma\Delta$ modulator using full feed-forward is introduced. It has two advantages: the unity signal transfer function and reduced signal swings inside the $\Sigma\Delta$ loop. These features greatly relax the DC gain and output swing requirements for Op-Amp in the low-voltage $\Sigma\Delta$ modulator. Implemented by a 0.18-${\mu}m$ CMOS technology, the $\Sigma\Delta$ modulator satisfies performance requirements for WCDMA and CDMA2000 standards.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.697-700
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• 2001

In this paper, the structural and electrical properties of the Sr$_{1-x}$ Ca$_{x}$TiO$_3$ (0$\leq$x$\leq$0.2) (0$\leq$r$\leq$0.2)-based grain boundary layer ceramics were investigated by X-ray, SEM and V-I system. Increasing the Ca content, the average grain size and the lattice constant were decreased. The relative density of all specimens was >96%. The 2nd phase formed by thermal diffusing from the surface lead to a very excellent electrical properties, that is, $\varepsilon$$_{r}$>50000, tan$\delta$<0.05, $\Delta$C< $\pm$ 10%.\pm$ 10%.%.

• 한국광학회:학술대회논문집
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• 한국광학회 2000년도 제11회 정기총회 및 00년 동계학술발표회 논문집
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• pp.314-315
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• 2000

레이저 매질은 흡수된 여기 파워에 의해 매질 내부에서 열이 발생하고, 매질 표면을 따라 냉각이 진행되어 매질 내부에서는 불균일한 온도분포가 발생하게 된다.$^{[1,2]}$ 레이저 매질의 굴절율은 온도에 따라 변하기 때문에 열복굴절과 열렌즈 현상이 일어나 레이저 출력의 손실 및 빔질의 저하를 초래하게 된다.$^{[1,3]}$ 선형 편광 광선을 이용하는 고체 레이저는 레이저 매질을 브루스터각으로 가공하거나 공진기 내부쉐 브루스터판을 삽입한다. 따라서, 선형 편광 광선은 열복굴절에 의한 위상 지연으로 타원 편광이 되고, 타원 편광 광선의 s-성분은 브루스터판에서 반사를 일으키게 되어 레이저 출력의 손실을 일으키게 되므로 레이저 공진기를 구성하는데 있어서 정량적인 열영향의 해석이 필요하다$^{[1,2,5]}$ 열영향에 의한 위상 지연은 방위각 방향과 반지름 방향으로 각각 $\Delta$ $n_{\Phi}$, $\Delta$ $n_{r}$ 만큼 생긴 굴절율의 차이로 발생하고 다음과 같이 표현할 수 있다.$^{[1]}$ (중략)이 표현할 수 있다.$^{[1]}$ (중략)

• 한국세라믹학회지
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• 제43권12호
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• pp.758-763
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• 2006

Perovskites with nominal compositions $Ln_{0.8}Sr_{0.2}CoO_{3-\delta}$ (Ln=Gd, Nd, Pr, Sm, or Yb) were fabricated as cathode materials using a solid-state reaction method for low-temperature operating Solid-Oxide Fuel Cells (SOFCs). X-ray diffraction analysis and microstructure observation for the sintered samples were performed. The ac complex impedance was measured in the temperature range of $600-900^{\circ}C$ in air and fitted with a Solartron ZView program. The crystal structure, microstructure, electrical conductivity, and polarization resistance of $Ln_{0.8}Sr_{0.2}CoO_{3-\delta}$ were characterized systematically.

• Progress in Superconductivity
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• 제10권2호
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• pp.133-138
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• 2009

The $Nd_{1+x}Ba_{2-x}Cu_3O_{7-{\delta}}$(Nd123) superconductor exhibits high performance in high magnetic field and high temperature. We have studied phase stability for Nd123 under reduced oxygen partial pressure and various heat-treatment conditions. The main phase is Nd123 and some samples contain small amounts of Nd422 depending on the temperature and oxygen partial pressure. The decomposition temperature decreases with decreasing oxygen partial pressure from $1052^{\circ}C(P(O_2)$=150 Torr) to about $845^{\circ}C(P(O_2)$=0.1 Torr). The liquidus line was steeper temperature with decreasing oxygen partial pressure. In same condition of oxygen partial pressure, the region of stable Nd123 phase was formed at slightly higher temperature than the region of stable YBCO phase.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.603-606
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• 2004

ZnO varistor ceramics were fabricated with variation of addition of $Nd_2O_3$ amount and the sintering temperature was $l150^{/circ}C$. The average grain sizes were showed decreased from $13.8{\mu}m$ to $4.7{\mu}m$, and varistor voltages were increased from 398 V to 657 V by added amount of $Nd_2O_3$. Nonlinear coefficient a of all were with increasing the amount of $Nd_2O_3$ more than 60, in case of added on 0.1mol% $Nd_2O_3$ was 87. And leakage current were less than $1_{\mu}A$ with applied at 82% of varistor voltage. The clamping voltage ratio of the specimes added 0.1mol% $Nd_2O_3$ was 1.38 at applied 25A [$8/20{\mu}s$]. In the specimen added 0.1mol% $Nd_2O_3$, endurence of surge current and deviation of varistor voltage were 7000A/$cm^2$, $\Delta-2.08%$, respectively.

• 한국정보전자통신기술학회논문지
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• 제13권1호
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• pp.8-16
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• 2020

본 논문에서는 polymerase chain reaction (PCR) 응용에 적합한 저잡음 CMOS 이미지 센서에 사용되는 컬럼-패러럴 analog-to-digital converter (ADC) 어레이를 위한 cascaded-of-integrator feedforward (CIFF) 구조의 단일 비트 2차 델타-시그마 모듈레이터를 제안하였다. 제안된 모듈레이터는 CMOS 이미지 센서에 입사된 빛의 신호에 해당하는 픽셀 출력 전압을 디지털 신호로 변환시키는 컬럼-패러럴 ADC 어레이를 위해 하나의 픽셀 폭과 동일한 10㎛ 컬럼 폭 내에 2개의 스위치드 커패시터 적분기와 단일 비트 비교기로 구현하였다. 또한, 모든 컬럼의 모듈레이터를 동시에 구동하기 위한 주변 회로인 비중첩 클록 발생기 및 바이어스 회로를 구성하였다. 제안된 델타-시그마 모듈레이터는 110nm CMOS 공정으로 구현하였으며 12kHz 대역폭에 대해 418의 oversampling ratio (OSR)로 88.1dB의 signal-to-noise-and-distortion ratio (SNDR), 88.6dB의 spurious-free dynamic range (SFDR) 및 14.3비트의 effective-number-of-bits (ENOB)을 달성하였다. 델타 시그마 모듈레이터의 면적 및 전력 소비는 각각 970×10 ㎛2 및 248㎼이다.