완전-차동형 CMOS OTA들을 이용한 시뮬레이티드 플로팅 인덕터의 설계 및 응용

신희종,정원섭,Shin, Hee-Jong,Chung, Won-Sup 대한전자공학회 2001 電子工學會論文誌-SC (System and control) Vol.38 No.1

두 개의 완전-차동형 OTA들과 하나의 커패시터를 이용한 시뮬레이티드 플로팅 인덕터를 제안했다. 제안한 플로팅 인덕터의 동작 원리를 기술했고, 실험 결과들을 제시했다. 실험 결과들은 이론적인 예측과 실험적인 성능이 잘 일치한다는 것을 보였고, 제안한 플로팅 인덕터가 기존의 인덕터들보다 약 두 배 큰 Q 인수를 가진다는 것을 보였다. 제안한 인덕터의 3차 일립틱 저역-통과 여파기에 응용 역시 제시하였다. A simulated floating inductor using two fully-differential OTA's and a capacitor is presented. The theory of operation is described and experimental results are used to verify theoretical predictions. The results show close agreement between predicted behavior and experimental performance. The proposed floating inductor has about two times higher Q factor than conventional designs. The application of the inductor to a ladder type third order ellitic low pass filer is also presented.

갈근 추출물이 난소 적출로 비만이 유발된 Rat의 체중 변화와 유전자 발현에 미치는 영향

신희종,유정은,정은혜,유동열 대한한방부인과학회 2012 大韓韓方婦人科學會誌 Vol.25 No.3

Objectives: GG is the EtOH fraction of extract of Pueraria lobata. In this study,we aimed to elucidate a possibility that GG reduce obesity and obesity-derived complications such as cardiovascular and metabolic disease. Methods: The effects of GG on the estrogen-deficient obese rats and the level of gene expression in muscle of rats were investigated. Results: GG decreased body weight in obese rats with estrogen deficiency. GG increased leptin gene expression in obese rats with estrogen deficiency. GG decreased TNFa gene expression in obese rats with estrogen deficiency. And GG increased PPAR-gamma, PGC-1a, Prdx6, FDFT1, and ACC gene expression of those in obese rats. Conclusions: We conclude GG might reduce body weight and regulate gene expression of muscle in obese rats.

Synthesis of heteroatoms-doped carbon via one-step chlorination process for electrocatalysis

신희종,성영은 한국공업화학회 2020 한국공업화학회 연구논문 초록집 Vol.2020 No.-

The introduction of heteroatoms into carbon materials has been widely used to boost the surface reactivity of carbon materials. Unlike nitrogen extensively investigated, the influence of boron in the synthesis of porous carbon materials has not been comprehensively understood. In this study, we successfully synthesized the heteroatom (boron, nitrogen, and/or oxygen)-doped highly nanoporous carbon materials via the chlorination process of carbonitride-boride starting materials. Boron dopants paly the roles of carbon structure linkers, which are the keys to alter the characteristics of porous carbon. This enabled to produce carbon materials enriched with reactive sites responsible to oxidation stability and electrochemical properties. Oxygen-rich carbide-derived carbon and nitrogen-rich carbonitride-derived carbon materials were synthesized through the present chlorination method, and they show the enhanced oxygen reduction reaction (ORR) catalytic performance.

Electrocatalytic CO₂ reduction to C²⁺ products through hydrogen-assisted C-C coupling

신희종,성영은 한국공업화학회 2020 한국공업화학회 연구논문 초록집 Vol.2020 No.-

Electrocatalytic reduction of CO2 into fuels and chemicals is promising route for CO2 utilization. Copper catalysts have been reported that they have properties to produce valuable hydrocarbon (C2+ product; ethylene) and alcohols. The formation of *CHO intermediates for C2+ formation is the key factor to achieve high activity and selectivity for multielectronic CO2 reduction. Better control for C2+ production may be possible via the C-C bond construction between the intermediates, thus the coupling process should be promoted on reaction mechanisms. We will suggest some strategies to boost the water dissociation on the copper electrode surface with various metal oxide cocatalysts, which can enhace water activation, CO adsorption and hydrogenation of adsorbed *CO to *CHO intermediate that can readily undergo coupling.

Electrochemical Hydrogen Peroxide Production with Cobalt-based Single Atom Catalysts

신희종,유종석,현택환,성영은 한국공업화학회 2020 한국공업화학회 연구논문 초록집 Vol.2020 No.-

H₂O₂ is one of the most important fundamental chemicals in industries as well as energy and environmental applications. Typically, oxygen reduction on catalytic sites follows two pathways: 2e- reduction to hydrogen peroxide, and 4e- reduction to water, depending on the adsorption mode and related dissociation barrier of the O-O bond on the catalytic surface. In this study, we want to differentiate 2e- vs. 4epathway of ORR mechanism according to the metal center in metal-oxo intermediates in the implication of electric current generation via O-O bond breaking barrier. Interestingly, guided by first principles calculations, we find that the catalytic properties of Co-N4 moiety can be tailored by fine-tuning its surrounding atomic configuration, resembling the structure-dependent catalytic properties of metalloenzymes. We could synthesize single atom electrocatalysts comprising an optimized Co-N4 moiety incorporated in nitrogen-doped graphene for H₂O₂ production.

저전압 저전력 바이폴라 선형 트랜스컨덕터와 이를 이용한 OTA에 관한 연구

신희종,정원섭,Shin, Hee-Jong,Chung, Won-Sup 대한전자공학회 2000 電子工學會論文誌-SC (System and control) Vol.37 No.1

저전압 저전력 신호 처리를 위한 새로운 바이폴라 선형 트랜스컨덕터와 이것을 이용한 연산 트랜스컨덕턴스 증폭기를 제안한다. 이 트랜스컨덕터는 이미터 디제네레이션 저항을 갖는 npn 차동쌍과 이 차동쌍에 직렬로 연결된 pnp 차동쌍으로 구성된다. 이 구성에서 넓은 선형성과 온도 안정성을 위해 pnp 차동쌍의 바이어스 전류는 npn 차동쌍의 출력 전류를 사용하고 있다. 제안한 OTA는 선형 트랜스컨덕터와 세 개의 전류 미러를 갖는 트랜스리니어 전류 셀로 구성된다. 제안된 트랜스컨덕터는 종래의 그것과 비교하였을 때 우수한 선형성과 저전압 저전력 특성을 갖는다. 실험 결과, 50 ${\mu}S$의 트랜스컨덕턴스를 갖는 트랜스컨덕턴스가 공급 전압 ${\pm}$3V에서 입력 전압 범위가 -2V에서 +2V 사이에 ${\pm}$0.06% 보다 작은 선형 오차를 갖는다. 전력 소비는 2.44 mW이다. 25 ${\mu}S$의 트랜스컨덕턴스를 갖는 OTA 시작품을 바이폴라 트렌지스터 어레이를 가지고 만들었다. OTA의 선형성은 제안한 트랜스컨덕터와 같다. OTA 회로는 또한 0.5 S/A의 감도로 바이어스 전류 변화에따라 4-디케이드(decade)에 걸쳐서 선형적인 트랜스컨덕턴스를 갖는다. 1A novel bipolar linear transconductor and its application to operational transconductance amplifier(OTA) for low-voltage low-power signal processing is proposed. The transconductor consists of a npn differential-pair with emitter degeneration resistor and a pnp differential-pair connected to the npn differential-pair in cascade. The bias current of the pnp differential-pair is used with the output current of the npn differential-pair for wide linearity and temperature stability. The OTA consists of the linear transconductor and a translinear current cell followed by three current mirrors. The proposed transconductor has superior linearity and low-voltage low-power characteristics when compared with the conventional transconductor. The experimental results show that the transconductor with transconductance of 50 ${\mu}S$ has a linearity error of less than ${\pm}$0.06% over an input voltage range from -2V to +2V at supply voltage ${\pm}$3V. Power dissipation of the transconductor was 2.44 mW. A prototype OTA with a transconductance of 25 ${\mu}S$ has been built with bipolar transistor array. The linearity of the OTA was same as the proposed transconductor. The OTA circuit also exhibits a transconductance that is linearly dependent on a bias current varying over four decades with a sensitivity of 0.5 S/A.

흡수눈물점플러그 사용 후 Keratograph를 이용한 안구 표면의 변화 연구

신희종,박창현,나경선,김현승 대한안과학회 2018 대한안과학회지 Vol.59 No.1

Purpose: The aim of our study was to evaluate short-term changes in corneal surface status via Keratography in dry eye patients after placement of an absorbable collagen plug (UltraPlug™; Surgical Specialties Corporation, Reading, PA, USA). Methods: Patients (n = 20 eyes, 20 subjects) diagnosed with dry eye were recruited for this prospective, 1-month clinical trial. The lacrimal puncta were blocked using absorbable collagen plugs. We evaluated clinical parameters and symptoms 1 month later. We assessed visual acuity, the score on the Ocular Surface Disease Index (OSDI) questionnaire, and keratographic tear meniscus height (TMH) and tear break-up time (TBUT) (K5M; Oculus Optikgerate GmbH, Wetzlar, Germany). We also measured TBUT classically, the corneal fluorescein staining score, and the Schirmer test result. Results: Significant improvements in the corneal staining and OSDI scores were observed 1 month after treatment (p = 0.006, p = 0.001, respectively), but no significant differences in the keratographic TMH and TBUT, the classical TBUT, or the Schirmer test data was observed (all p > 0.05). Conclusions: Blocking of the lacrimal punctum with an absorbable collagen plug effectively improved clinical symptoms and objective indicators in dry eye patients, the corneal staining score and OSDI scores improved significantly. However, no significant improvements in keratographic TMH and TBUT were observed; this was of concern. Longer-term studies with more patients are required. 목적: 안구건조증 환자를 대상으로 Collagen absorbable plug를 사용하여 눈물점 폐쇄 전과 후의 Keratograph를 이용한 단기간 안구표면 변화에 대하여 알아보고자 한다. 대상과 방법: 안구건조증 환자 20명 20안을 대상으로 Collagen absorbable plug인 UltraPlug™ (Surgical Specialties Corporation, Reading, PA, USA)를 사용하기 전과 일주일 후에 각각 교정시력, Ocular Surface Disease Index (OSDI) score, Keratograph (K5M; Oculus Optikgerate GmbH, Wetzlar, Germany)를 통한 눈물띠 높이 및 눈물막파괴시간, 형광색소 염색을 이용하여 측정한 눈물막파괴시간 및 각막상피병증검사, 쉬르머검사를 비교해 보았다. 결과: 흡수성 눈물점마개를 통한 눈물점 폐쇄 전후에 형광색소 염색을 이용하여 측정한 각막상피병증검사, OSDI score에 있어서 유의한 차이를 보였으나(p-value=0.006, p-value=0.001, 각각), 형광색소 염색을 이용하여 측정한 눈물막파괴시간, 쉬르머검사, Keratograph 를 이용한 눈물띠 높이 및 눈물막파괴시간 결과에서는 유의한 차이가 없었다(p-value >0.05). 결론: 각막상피병증검사 결과 및 OSDI score가 유의하게 호전된 것을 통해 흡수성 눈물점마개는 안구건조증 증상 호전에 있어 효과가 있는 것으로 보인다. 그러나 이번 연구에서 알아보고자 했던 주요 관심사 중 하나인 Keratograph를 이용해 측정한 눈물띠 높이 및 눈물막파괴시간을 통해서는 유의하게 호전된 것을 확인할 수 없었다. 추후 더 많은 환자들의 장기간 경과 관찰을 통해 결과에 대한 보완이 필요할 것으로 보인다.

Ezra Pound의 언어관 : 그 내재적 모순의 필연성과 그 의의

신희종 한국현대영어영문학회 1996 현대영어영문학 Vol.40 No.1

Porous titanium nitride nanotubes as high performance catalyst supports for the oxygen reduction reaction

신희종,김형일,정동영,최원용,성영은 한국공업화학회 2014 한국공업화학회 연구논문 초록집 Vol.2014 No.1

We designed a non-carbon TiN nanotube to be used as a support for Pt in facilitating the oxygen reduction reaction. The catalyst exhibited high activity and stability when compared with conventional Pt/C catalysts. The accelerated durability test (ADT) revealed that the novel supporting material can dramatically enhance the durability of the catalyst and maintain the electrochemically active surface area (ECSA) of Pt. The experimental data verified the strong metal/support interaction between Pt nanoparticles (NPs) and the TiN NTs support. The surface of the TiN NTs can be described as being similar to the shape of a human spine, which may function as a shield for recapturing and preventing Pt atoms from dissolving into the electrolyte. This new approach opens a reliable path for designing various TiN nanotubes as catalyst supports for a wide range of applications in energy conversion processes.

실험계획법을 이용한 텔레매틱스 HMI 평가에 관한 연구

신희종(Heejong Shin),유시복(Sibok Ryu),우진명(Jinmyung Woo),천환규(Hwankyu Chun),이장일(Jangil Lee),서명원(Myungwon Suh) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11

Recently, telematics devices have been used for driver’s safety and convenience .Telematics market including navigation is getting bigger and bigger. However, traffic accident from using telematics equipment is also increasing. Drivers may lose glance using navigation, and driver’s workload will also grow by driver’s distraction. This thesis is base on the study about the influence on the driver’s workload according to combination of display by DOE(design of experiment). The main object of this thesis is measuring the workload according to the telematics usage by HMI (Human Machine Interface) in the virtual reality. The result of these experiments is that workload when driver used navigation was different with a style of text type. Also, it confirmed the significant result from the statistics analysis.