• Journal of electromagnetic engineering and science
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• 제9권2호
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• pp.98-104
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• 2009

An InGaP/GaAs MMIC LC VCO designed with Harmonic Noise Frequency Filtering(HNFF) technique is presented. In this VCO, internal inductance is found to lower the phase noise, based on an analytic understanding of phase noise. This VCO directly drives the on-chip double balanced mixer to convert RF carrier to IF frequency through local oscillator. Furthermore, final power performance is improved by output amplifier. This paper presents the design for a 1.721 GHz enhanced LC VCO, high power double balance mixer, and output amplifier that have been designed to optimize low phase noise and high output power. The presented asymmetric inductance tank(AIT) VCO exhibited a phase noise of -133.96 dBc/Hz at 1 MHz offset and a tuning range from 1.46 GHz to 1.721 GHz. In measurement, on-chip down-converter shows a third-order input intercept point(IIP3) of 12.55 dBm, a third-order output intercept point(OIP3) of 21.45 dBm, an RF return loss of -31 dB, and an IF return loss of -26 dB. The RF-IF isolation is -57 dB. Also, a conversion gain is 8.9 dB through output amplifier. The total on-chip down-converter is implanted in 2.56${\times}$1.07 mm$^2$ of chip area.

• Transactions on Electrical and Electronic Materials
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• 제13권1호
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• pp.43-46
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• 2012

Organic solar cell devices were fabricated using poly[9-(1-octylnonyl)-9H-carbazole-2.7-diyl]-2.5-thiophenediyl-2.1.3-benzothiadiazole-4.7-diyl-2.5-thiophenediyl] PCDTBT/ [6,6]-phenyl $C_{71}$ butyric acid methyl ester (PC71BM) active layer deposited by spin coating. Moreover, the relationship between solar cell performance and buffer layer thickness was investigated by spin coating speed and AFM imaging of the buffer layer surface. The performance of the organic solar cell with spin-coated active layer was then evaluated, and the power conversion efficiency of the solar cell was determined to be > 5%.

• ETRI Journal
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• 제46권2호
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• pp.323-332
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• 2024

Receiver and transmitter monolithic microwave integrated circuit (MMIC) multifunction chips (MFCs) for active phased-array antennas for Ka-band satellite communication (SATCOM) terminals have been designed and fabricated using a 0.15-㎛ GaAs pseudomorphic high-electron mobility transistor (pHEMT) process. The MFCs consist of four-channel radio frequency (RF) paths and a 4:1 combiner. Each channel provides several functions such as signal amplification, 6-bit phase shifting, and 5-bit attenuation with a 44-bit serial-to-parallel converter (SPC). RF pads are implemented on the bottom side of the chip to remove the parasitic inductance induced by wire bonding. The area of the fabricated chips is 5.2 mm × 4.2 mm. The receiver chip exhibits a gain of 18 dB and a noise figure of 2.0 dB over a frequency range from 17 GHz to 21 GHz with a low direct current (DC) power of 0.36 W. The transmitter chip provides a gain of 20 dB and a 1-dB gain compression point (P1dB) of 18.4 dBm over a frequency range from 28 GHz to 31 GHz with a low DC power of 0.85 W. The P1dB can be increased to 20.6 dBm at a higher bias of +4.5 V.

• 한국토양비료학회지
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• 제46권2호
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• pp.105-111
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• 2013

Lysobacter capsici YS215의 특성 및 뿌리혹선충 방제에 미치는 영향을 조사하였다. YS1215의 생육은 배양 6일째 최고였으며, 생육에 따른 chitinase와 gelatinase의 활성은 각각 3일째와 5일째에 가장 높은 활성을 보였다. YS1215 배양액이 선충 피해 방제와 식물 생장에 미치는 영향을 조사해 본 결과, 5주째 식물 지상부 생체중 및 건조중에서 배양액 반량구에서 가장 높게 나타났지만, 9주째에는 미생물 배양액, 미생물 배양액 반량구 및 배지액 처리구에서 차이를 보이지 않았다. 하지만 9주째 미생물 배양액, 미생물 배양액 반량구 및 배지액 처리구가 물처리구 보다 높게 나타났다. 지상부 길이에서는 미생물 배양액 반량구 처리구가 가장 높았다. 선충 피해 방제에 있어서 난낭수, 뿌리혹수 및 토양내 유충수에서 각각 농약 처리구에서 가장 낮게 나타났으나, 미생물 배양액 처리구와의 유의적 차이는 보이지 않았다. 미생물 배양액 처리구는 미생물 배양액 반량구 및 물 처리구와는 유의적 차이가 있는 것으로 조사되었다. 그러므로 다양한 분해효소를 생성하는 L. capsici YS1215의 뿌리혹선충방제에 대한 충분한 가능성과 가치가 있다고 사료된다.

• 한국전자파학회논문지
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• 제22권11호
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• pp.1034-1046
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• 2011

본 논문에서는 X-대역에서 GaN HEMT 소자의 로드-풀 측정을 통한 40 W급 전력증폭기 모듈의 설계, 제작을 보였다. 전력증폭기의 설계에 적용하기 위한 능동 소자로, 최근 발표된 TriQuint사의 GaN HEMT 소자를 선정하였다. 로드-풀 측정 시스템의 임피던스 튜너의 임피던스 범위 제한으로 인하여, 시험치구 내에 사전-정합 회로를 구성하였다. 사전-정합 회로가 포함된 로드-풀 측정을 통해 최적 입 출력 임피던스를 도출하기 위하여, 사전-정합 회로의 2-포트 S-파라미터가 필요하며, 이의 새로운 추출 방법을 제안하였다. 이와 같이 결정된 사전-정합 회로의 S-파라미터를 반영한 로드-풀 측정을 통해 도출된 최적 입 출력 임피던스는 데이터 시트와 근접한 결과를 주며, 이를 통해 측정의 타당성을 확인하였다. 전력증폭기의 정합 회로는 도출된 최적 임피던스로부터 EM co-simulation을 이용하여 설계하였다. 제작된 전력증폭기는 15${\times}$17.8 $mm^2$으로 소형의 크기를 가지며, 10 usec의 펄스 폭, 10 % duty의 펄스 입력 및 드레인 스위칭 상태에서, 9~9.5 GHz 대역 내 출력은 46.7~46.3 dBm, 전력 이득은 8.7~8.3 dB, 효율은 약 35 %의 특성을 보인다.

• Journal of Microbiology and Biotechnology
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• 제17권12호
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• pp.2018-2026
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• 2007

A bacterium, Pseudomonas aeruginosa BM114, capable of accumulating a blend of medium-chain-length (MCL)- and short-chain-length (SCL)-polyhydroxyalkanoic acid (PHA), was isolated. Salicylic acid (SA), without being metabolized, was found to specifically inhibit only the accumulation of MCL-PHA without affecting cell growth. An addition of 20 mM SA selectively inhibited the accumulation of MCL-PHA in decanoate-grown cells by 83% of the control content in one-step cultivation, where overall PHA accumulation was inhibited by only ${\sim}11%$. Typically, the molar monomer-unit ratio of the PHA for 25 mM decanoate-grown cells changed from 46:4:25:25 (=[3-hydroxybutyrate]:[3-hydroxycaproate]: [3-hydroxyoctanoate]:[3-hydroxydecanoate]) at 0 mM SA (dry cell wt, 1.97 g/l; PHA content, 48.6 wt%) to 91:1:4:4 at 20 mM SA (dry cell wt, 1.85 g/l; PHA content, 43.2 wt%). Thus, the stimulation of SCL-PHA accumulation was observed. Growth of P. aeruginosa BM114 on undecanoic acid also produced a PHA blend composed of 47.4% P(3HB-co-3-hydroxyvalerate) and 52.6% P(3-hydroxyheptanoate-co-3-hydroxynonanoate-co-3-hydroxyundecanoate). Similar to the case of even-carboxylic acids, SA inhibited the accumulation of only MCL-PHA, but stimulated the accumulation of SCL-PHA. For all medium-chain fatty acids tested, SA induced a stimulation of SCL-PHA accumulation in the BM114 strain. SA could thus be used to suppress only the formation of MCL-PHA in Pseudomonas spp. accumulating a blend of SCL-PHA and MCL-PHA.

• Bulletin of the Korean Chemical Society
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• 제33권9호
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• pp.3061-3070
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• 2012

Novel 2-hexylthieno[3,2-b]thiophene-containing conjugated molecules have been synthesized via a reduction reaction using tin chloride in an acidic medium. They exhibited good solubility in common organic solvents and good self-film and crystal-forming properties. The single-crystalline objects were fabricated by a solvent slow diffusion process and then were employed for fabricating field-effect transistors (FETs) along with thinfilm transistors (TFTs). TFTs made of 5 and 6 exhibited carrier mobility as high as 0.10-0.15 $cm^2V^{-1}s^{-1}$. The single-crystal-based FET made of 6 showed 0.70 $cm^2V^{-1}s^{-1}$ which was relatively higher than that of the 5-based FET (${\mu}=0.23cm^2V^{-1}s^{-1}$). In addition, we fabricated organic photovoltaic (OPV) cells with new 2-hexylthieno [3,2-b]thiophene-containing conjugated molecules and methanofullerene [6,6]-phenyl C61-butyric acid methyl ester ($PC_{61}BM$) without thermal annealing. The ternary system for a bulk heterojunction (BHJ) OPV cell was elaborated using $PC_{61}BM$ and two p-type conjugated molecules such as 5 and 7 for modulating the molecular energy levels. As a result, the OPV cell containing 5, 7, and $PC_{61}BM$ had improved results with an open-circuit voltage of 0.90 V, a short-circuit current density of 2.83 $mA/cm^2$, and a fill factor of 0.31, offering an overall power conversion efficiency (PCE) of 0.78%, which was larger than those of the devices made of only molecule 5 (${\eta}$~0.67%) or 7 (${\eta}$~0.46%) with $PC_{61}BM$ under identical weight compositions.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.154.2-154.2
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• 2016

In this work, we introduce a solution-processed CdS interlayer for use in inverted bulk heterojunction (BHJ) solar cells, and compare this material to a series of standard organic and inorganic cathode interlayers. Different combinations of solution-processed CdS, ZnO and conjugated polyelectrolyte (CPE) layers were compared as cathode interlayers on ITO substrates to construct inverted solar cells based on $PTB7:PC_{71}BM$ and a $P3HT:PC_{61}BM$ as photoactive layers. Introduction of a CdS interlayer significantly improved the power conversion efficiency (PCE) of inverted $PTB7:PC_{71}BM$ devices from 2.0% to 4.9%, however, this efficiency was still fairly low compared to benchmark ZnO or CPE interlayers due to a low open circuit voltage ($V_{OC}$), stemming from the deep conduction band energy of CdS. The $V_{OC}$ was greatly improved by introducing an interfacial dipole (CPE) layer on top of the CdS layer, yielding outstanding diode characteristics and a PCE of 6.8%. The best performing interlayer, however, was a single CPE layer alone, which yielded a $V_{OC}$ of 0.727 V, a FF of 63.2%, and a PCE of 7.89%. Using $P3HT:PC_{61}BM$ as an active layer, similar trends were observed. Solar cells without the cathode interlayer yielded a PCE of 0.46% with a poor $V_{OC}$ of 0.197 V and FF of 34.3%. In contrast, the use of hybrid ZnO/CPE layer as the cathode interlayer considerably improved the $V_{OC}$ of 0.599 V and FF of 53.3%, resulting the PCE of 2.99%. Our results indicate that the CdS layer yields excellent diode characteristics, however, performs slightly worse than benchmark ZnO and CPE layers in solar cell devices due to parasitic absorption below 550 nm. These results suggest that the hybrid inorganic/organic interlayer materials are promising candidates as cathode interlayers for high efficiency inverted solar cells through the modification of interface contacts.

• 발명하는 사람들
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• 46호
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• pp.1-16
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• 2006

'2006 대한민국 여성 발명품 박람회' 개최/'발명의 달 5월' 행사 풍성히 열려/'제12회 여성발명 우수사례 발표회' 열려/;꽃꽃이 용기' 출원동향 급격히 늘어나/특허청 '소멸특허정보 서비스' 제공한다/김열 특허청 차장 승진 임명/BM 특허 출원, 개인은 줄고 기업은 늘고/5월부터 특허료, 우선심사신청료 인하/현장 스케치/특허청과 한국전력 기술.특허정보 공유 양해각서 체결/독일과 '장미전쟁', 한국 승리/'제34회 제네바 국제발명전'에서 전원 수상 기록/국제 특허 전문가 한 자리에 모였다/특허청, 해외지재권 침해 소송비용 지원/국가연구 개발사업 지원하는 'R&D 특허센터' 출범/'특허 고객 고층 해결 안방 서비스' 개시/한국특허정보원, 다양한 캠페인 통해 사회공헌 활동/특허청, 과학기술 전문인력 50명 특별채용/'특허기술이전 박람회' 개최/취업 위해 일본 기업에 IT특허 기술 유출/부조리 신고자에 포상금 지급/역사 속의 발명품/하루 10분 발명교실/특허Q&A/'주부에서 발명가로, 필요에 의해 발병이 시작됐습니다'/여주초등학교 발명교실/아이디어 착상 및 발명 기법/여성 발명 활동 더욱 장려해야/무리에의 마가린/세계 상표제도 더욱 가까워져/특허청,'아시아 특허정보 허브'로 급부상/'2006 발명 특허 페스티벌' 개최/지리적 명칭, 신문제호 상표등록 안된다/리빙 아이디어/특허기술사업화에 3천89척원 지원/'찾아가는 심사 서비스' 대리인 사무소까지 확대/문화콘텐츠 식별체계 첫 선 보여/한국여성발명협회 회원사 발명품 가이드/

• 한국자기학회지
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• 제9권5호
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• pp.234-238
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• 1999

각종 microwave용 통신기기 소자 및 고주파용 memory 소자로 사용하기 위해서 각형비가 크고 보자력이 작은 lithium ferrite를 개발하고 물리적인 특성을 조사하기 위하여 Li0.48-0.5xBi0.02Ni0.04ZnxFe2.46-0.5xO4의 조성식을 갖는 시편을 제조하였다. ZnO을 첨가하여 변화시킴에 따라 잔류자기(Bm)가 증가하고 보자력(Hc)이 낮아졌으나 각형비 R은 감소하였다. 105$0^{\circ}C$에서 소결한 시편의 경우 R=0.82, Hc=1.8Oe로 나타났고 110$0^{\circ}C$에서 소결한 시편의 경우 R=0.75 및 Hc=1.70Oe인 값을 얻었다. Tc는 463$^{\circ}C$로 측정되었고 주변온도 변화에 대한 Br값의 변화가 매우 안정된 0.09~0.11 값으로 나타났다.