정확한 Closed-Form 그린함수를 이용한 코플래너 도파로 불연속 해석

강연덕,송성찬,이택경 한국항행학회 2003 韓國航行學會論文誌 Vol.7 No.2

실수축 상의 적분 방법에 의한 정확한 closed-form 그린함수를 이용하여 코플래너 도파로의 불연속에 대한 공간영역 full-wave 해석을 하였다. MPIE(Mixed Potential Integral Eqution)를 풀기 위한 수치계산 방법으로는 삼각형 요소를 이용한 갤러킨 방법을 사용하였다. 경계면에서 삼각형 요소상의 기저함수로는 선형함수를 사용하였으며, 관측점과 전원점이 일치하는 특이점 근방의 적분 계산을 위해 면적분을 선적분 형태로 바꾸어 피적분 함수의 특이점이 사라지도록 하는 해석적인 방법을 사용하였다. 실수축 적분방법에 의한 그린함수를 이용함으로써 불연속에 대한 정확한 특성을 구하였다. By using accurate closed-form Green's functions obtained from real-axis integration method, the full-wave analysis of CPW discontinuities are performed in space domain. In solving MPIE(Mixed Potetial Integral Equation), Galerkin's scheme is employed with the linear basis functions on the truangular elements in air-dielectric boundary. In the singular integral arising when the observation point and source point coincides, the surface integral is transformed into the line integral and the integral is evaluated by regular integration. By using the green's function from the real-axis integration method, the discontinuities are characterized accurately.

세포외 기록용 차동증폭기

이강준,김현택 한국심리학회 한국심리학회지 생물 및 생리 Vol.5 No.1

단단위 활동(single unit activity: SUA) 및 다단위 활동(multiple unit activity: MUA)을 기록할 수 있는 증폭기를 소개한다. 증폭기는 최첨단 증폭기와 후단 증폭기로 분리되어 있으며 두 부분 모두에서 높은 동상신호 제거비를 얻기 위해 차동증폭회로가 사용되었다. 높은 입력임피던스를 얻기 위해 접합형 전계효과 트랜지스터가 사용되었다. 후단 증폭기에는 또한 여파기와 완충증폭기를 삽입하여 원하는 주파수대의 뉴런활동을 선별할 수 있도록 하였다. 본 증폭기는 고입력 임피던스, 저잡음, 광대역 증폭 특성을 지닌 기기로서, 금속 전극을 사용한 다단위 기록과 미세유리관 전극을 사용한 단단위 기록에서 만족한 성능을 보였다. An amplifier was designed for extracellular recording of unit activity. It consists of a head stage amplifier and a postamplifier. The head stage amplifier and the postamplifier have differential input circuits. The amplifier had a high common mode rejection ratio(CMRR), well-defined gains, a low noise character, and a wide dynamic range. Multiple unit activity(MUA) and single unit activity(SUA) could be recorded satisfactorily in animals with the chronically implanted metal electrode and with the acute micropipette electrode in the brain.

포기/비포기 시간비가 활성슬러지 floc의 특성에 미치는 영향

김강호,문병현,이택순,서규태 7개 국립대학교 환경연구 논문집 공동발행 위원회 2002 환경연구논문집 Vol.2 No.1

Many researches on SBR(Sequencing batch Biological Reactor) for the removal efficiency of contaminants and effects of operation mode in effluent have been conducted. However, little studies for the characteristic of biological floc affected by operation mode have been made. The purpose of this study is to compare the effect factors on the removal efficiency of nitrogen and phosphorus in SBR system. And also it is to look for new information on the size and characteristics of biological floc by changed aerobic/anaerobic time ratio. Results shown that the removal efficiency of organic matter, nitrogen and phosphorus was higher in the operation mode of higher aerobic/anaerobic time ratio. The floc size and fractal dimension produced in higher aerobic/anaerobic time ratio were larger. These result implied that the settling characteristics of floc could be produces in the operation mode of higher aerobic/anaerobic time ratio.

디지탈 통신 학습 시뮬레이터

송현교,김연구,이택희,강민구 호남대학교 정보통신연구소 1995 정보통신연구 Vol.4 No.-

본 논문에서는 실제 통신망에서 발생할 수 있는 데이타 전송과정을 컴퓨터상에 시뮬레이션하는 프로그램으로서, PC의 WINSOW 환경하에서 Visual-Basic을 활용하여 통신신호의 흐름과정을 하나의 화면에서 구현하도록 부호화와 변조파형을 표현하고 이 신호의 복조와 복호과정을 시뮬에이션한다. 아울러 통신채널에서 발생하는 랜덤오류를 제어하는 오류정정을 포함함으로서 통신이론을 이해하고 학습하는데 많은 도움이 될 수 있도록 통신신호에 대한 그래픽 처리에 목적을 둔다. In this thesis, the graphic signal for communication is presented in the WINDOW using `Visual-Basic'. All signals of PCM encoding/decoding and modulation/demodulation are processed in the same picture. Especially, error control schemes which are parity check, longiudinal redundancy check, cyclic redundancy check, are described for more reliable communication.

재발 또는 불응성 비호즈킨 림프종 환자에서 CDME 구제항암화학요법 후 고용량 항암화학요법 및 자가말초혈액 조혈모세포이식의 효과

김세형,한강원,배상병,김찬규,이남수,이규택,박성규,원종호,홍대식,박희숙 순천향의학연구소 2004 Journal of Soonchunhyang Medical Science Vol.10 No.1

Background and objectives : The long-term survival in patients with non-Hodgkin's lymphoma (NHL) after conventional dose chemotherapy is about 35% and the rest of the patients tend to have relapse. So, in relapsed or refractory NHL, we compared the outcome of patients undergoing high-dose chemotherapy with autologous peripheral blood stem cell transplantation(APBSCT) with only salvage chemotherapy of cisplatin, dexamethasone, mitoxantrone, and etoposide(CDME). Materials and methods : From June 1993 to December 1999, 25 patients with relapsed or resistant NHL were treated with CDME regimen as salvage chemotherapy. Twelve patients were received four cycles of CDME chemotherapy, and 13 patients were received high-dose chemotherapy with APBSCT following two cycles of CDME chemotherapy. Results : The median follow-up duration was 12.8 months(range:4-68). The overall response rate was 41.7% (complete response rate 25%, partial response rate 16.7%) in 12 patients with CDME only. Thirteen patients who were treated with high-dose chemotherapy with APBSCT achieved 61.5% complete response rate and 15.4% partial response rate, with an overall response rate of 76.9%. The estimated 3-year progression-free survival rate was significantly higher among patients who received high-dose therapy than patients who received CDME only(41.5% vs 20.0%, p<0.05). And, 3-year overall survival rate was significantly higher among patients who received high-dose therapy(51.3% vs 25.0%, p <0.05). Conclusions : In relapsed or refractory NHL, CDME chemotherapy is an effective salvage chemotherapy and allow peripheral blood stem cell collection. Also, high-dose chemotherapy with APBSCT following CDME is superior to CDME salvage chemotherapy only.

태양광 발전시스템을 위한 계통 연계형 PWM 인버터의 변조지연 보상

성낙규,한경희,강승욱,이승환,유택빈 明知大學校 産業技術硏究所 1995 産業技術硏究所論文集 Vol.14 No.-

Since the residential load is an AC load, while the output of solar cell is a DC power, the photovoltaic system needs the DC/AC converter to utilize solar cell and must provide the sinusoidal wave current and voltage, at unity power factor in the case of driving to interact with utility line. PWM modulator must do stable modulation even though it contains the disturbance like a distortion and noise, and it needs compensation method, because there is a timing interval between sampling points and carrier waves, while the synchronous signal is controlled by the micro processor. In this paper, we maximaze output of solar cells which is propotional to variation of insolation, using single phase PWM voltage source inverter, and we can drive in high power factor with utility line by control and compensation method which is concerned with synchronous signal distortion and modulation delay, using low pass filter and phase shifter.

Characterization of antimicrobial resistance and class 1 integrons found in <i>Escherichia coli</i> isolates from humans and animals in Korea

Kang, Hee Young,Jeong, Young Sook,Oh, Jae Young,Tae, Sung Ho,Choi, Chul Hee,Moon, Dong Chan,Lee, Won Kil,Lee, Yoo Chul,Seol, Sung Yong,Cho, Dong Taek,Lee, Je Chul Oxford University Press 2005 The Journal of antimicrobial chemotherapy Vol.55 No.5

<P><I>Objectives</I>: Antimicrobial resistance and class 1 integrons found in <I>Escherichia coli</I> isolates from humans and animals in Korea were characterized.</P><P><I>Methods</I>: <I>E. coli</I> isolates were examined for susceptibility to antimicrobial agents. Integrase genes were amplified. Gene cassette regions for classes 1 and 2 integrons were amplified and sequenced. Conjugal transfer and Southern hybridization were performed to determine the genetic localization of class 1 integrons. The clonal relationship of <I>E. coli</I> isolates carrying an identical cassette array was analysed by PFGE.</P><P><I>Results</I>: Commensal <I>E. coli</I> isolates from animals were highly resistant to commonly used antimicrobial agents such as tetracycline, sulfamethoxazole, streptomycin, ampicillin and carbenicillin. Integrons were most prevalent in commensal <I>E. coli</I> isolates from poultry (44%), followed by clinical isolates from humans (33%), commensal isolates from swine (23%) and humans (13%). <I>dfrA17-aadA5</I>, <I>dfrA12-orfF-aadA2</I> and <I>aadA1</I> were found most frequently in <I>E. coli</I> isolates from humans, poultry and swine, respectively. Class 1 integrons were mostly located in conjugative plasmids. <I>E. coli</I> isolates carrying an identical cassette array were phylogenetically unrelated.</P><P><I>Conclusions</I>: The use of antibiotics is strongly associated with antimicrobial resistance. <I>E. coli</I> isolates from different sources may select a specific gene cassette by antibiotic selective pressure, which results in differences in class 1 integrons. The horizontal transfer of class 1 integrons through conjugative plasmids seems to be responsible for wide dissemination of a particular type of class 1 integron.</P>

Regional Analysis of Chemical Vapor Deposition Using Direct Simulation Monte Carlo Method

Kang-In Lee(이강인),Hyun-Taek Lee(이현택),Jang-Yeob Lee(이장엽),Sung-Hoon Ahn(안성훈) (사)한국CDE학회 2015 한국 CAD/CAM 학회 학술발표회 논문집 Vol.2015 No.하계

Shallow groundwater system monitoring on controlled CO2 release sites: a review on field experimental methods and efforts for CO2 leakage detection

Kang-Kun Lee,Seung Hyun Lee,Seong-Taek Yun,Sung-Wook Jeen 한국지질과학협의회 2016 Geosciences Journal Vol.20 No.4

Carbon dioxide capture and sequestration (CCS) is a promising alternative for reduction of greenhouse gas emission. However, injected CO2 in deep formation has potential to leak into a shallow aquifer. Thus, although it is challenging, development of detection technologies in a shallow aquifer region is essential to assure the long term safety of a CCS project. Recently, field scale experiments were carried out around the world to identify CO2 leakage and to investigate effects on groundwater quality in shallow aquifers. From the literature, 8 controlled CO2 release test sites and 9 experimental cases were identified. In those sites, CO2 was artificially injected around the shallow aquifer region as CO2-infused groundwater phase or gas phase for identifying environmental effects caused by CO2 injection. This paper reviews the hydraulic heterogeneity, mineral compositions, monitoring systems, and environmental parameters required for leakage detection at each site. For constructing a controlled test bed, inclined wells, horizontal wells, and multiple injection wells were identified as reliable injection components. It was also identified that the injected CO2 migration and its effects were monitored through the constructed monitoring networks. The previous operation cases show that continuous monitoring of pH, electrical conductivity (EC), Ca and Mg concentrations is the most basic and important factor for leakage detection. Trace elements and isotopes were also widely used to determine the CO2 leakage. The Korea CO2 Storage Environmental Management (K-COSEM) research center is going to construct an environmental impact test (EIT) facility for developing CO2 leakage detection methods in a shallow aquifer region in Korea. The challenging issues will include the fate and transport of CO2 from the fractured zone to the saturated zone and to the unsaturated soil. Based on the lessons learned from the previous tests, environmental monitoring technologies will be developed through the analysis of the time series data of hydrogeochemical parameters for the planned EIT facility in Korea.

한국인에서 발생한 섬유층판 간세포암 1예

이석호,조재원,이규택,강인구,최규완,백승운,이종균,고광철,이종철,박철근,이준혁,오영륜 대한소화기학회 1998 대한소화기학회지 Vol.32 No.1

Fibrolamellar hepatocellular carcinoma (FLHCC) is a distinct variant of ordinary hepatocellular carcinoma (HCC) and is very rare in the Orient. Contrary to ordinary HCC, the FLHCC has very good prognosis and usually occurs in adolescents and young adults without sexual preference. In addition, it is rarely associated with liver cirrhosis and hepatitis B virus. The FLHCC presents a high resectability rate. Most cases of FLHCC have been reported in the Western countries and only nine cases have been reported in the Orient. We present here a case of FLHCC observed in a 48 year old man. The patient had no subjective symptoms when the tumor was revealed by ultrasonography. The patient had many ch'arateristics of FLHCC (i.e,, no association with HBV or HCV, normal range of alphafetoprotein, no evidence of cirrhosis). However, he was older than average-aged patient with FLHCC. The tumor was removed by right antero-inferior segmententomy of the liver and diagnosed as FLHCC. To our knowledge, this report is the fast case in Korea.