입내 분산형 Al₂O₃/Ag 나노복합체의 제조와 특성

천승호,한인섭,히데오 아와지,Cheon, Sung-Ho,Han, In-Sub,Awaji, Hideo 한국세라믹학회 2007 한국세라믹학회지 Vol.44 No.4

Alumina/silver ($Al_2O_3/Ag$) nanocomposites with Ag content up to 9 vol% were prepared from nanopowder by soaking method using ${\gamma}-Al_2O_3$ of needle type and spark plasma sintering (SPS). The mechanical properties of specimens were investigated three-point flexural strength and toughness as a function of the Ag contents. The maximum flexural strength of the alumina/silver nanocomposite was 850 MPa for the 1 vol% composite, and also higher than monolith alumina as about 800 MPa at 3, 5, and 7 vol% Ag contents. Fracture toughness by single edged V-notch beam (SEVNB) was $4.05MPa{\cdot}m^{1/2}$ for the 3 vol% composite and maintained about $4.00MPa{\cdot}m^{1/2}$ at 5, and 7 vol% Ag content. Microstructure of fracture surface for each fracture specimens was observed. Due to the inhibition effect of alumina grain growth, the average grain size of nanocomposites depends on the content of Ag nano particles. The fracture morphology of nanocomposite with dislocation (sub-grain boundary) by silver nano-particles of second phases in the alumina matrix also showed transgranular fracture-mode compare with intergranular of monolith alumina. Thermal conductivity of specimens at room temperature was about 40 W/mK for the 1 vol% Ag content.

대전시 유통 과실류의 농약 잔류 실태 및 위해성 평가

한국탁,박혜진,이규승,김일중,김규섭,조성민 한국환경농학회 2002 한국환경농학회지 Vol.21 No.4

대전시 노은 도매 시장에 서 채취한 과실류와 6종의 농약잔류량을 조사한 후 이에 대한 위해성 평가를 실시하였다. 전체 120건 분석시료 중 70.8%가 농약 성분이 검출되었고 그중 1.67%가 잔류허용기준치을 초과하여 검출되었다. 검출 비율이 높은 시료는 사과, 복숭아, 포도 등이었다. 검출된 성분에서 살충제는 유기인계, 합성 pyrethroid계, 유기염소계가 비슷한 비율로 검출되었고, 살균제에서는 특히 procymidone(dicarboximide계)과 chlorothalonil(유기염소계)의 검출비율이 높았다. 검출빈도가 높은 성분은 chlorothalonil, chlorpyrifos, fenvalerate, procymidone, deltamethrin, EPN의 순이었다. 위해성을 평가하기 위해서 각 농작물에 대한 농약의 추정섭취량과 ADI를 비교한 결과, 추정섭취량의 비율이 1.221%이하로 나타나 그 영향이 매우 낮은 것으로 판단되었다. 이것은 농약 잔류 허용기준치를 초과한 농작물인 복숭아에서 chlorothalonil, EPN에 대해서도 동일한 결과를 나타내었다. Pesticide residues in some fruits collected at Noeun wholesale market, Daejeon were surveyed and assessed its risk. In 120 samples, the detection rate of pesticide was 70.8% and the rate exceed MRL was 1.67%. Highly detection rate of commodities was apple, peach and grape. Organophosphorus, organochlorine and pyrethroid insecticide were found with similar rate relatively, but most of fungicides were procymidone(dicarboximides) and chlorothalonil(organochlorine). The order of detected pesticide were chlorothalonil, chlorpyrifos, fenvalerate, procymidone, deltamethrin and EPN. In order to assess risk, estimated intake amount of each pesticide was compared to ADI. Although some peach were exceed MRL, the total amount and uptake pesticides was less than 1.22% comparing to ADI.

초고속 InGaAsP광 변조기 설계에 관한 연구

한상국,한섭 연세대학교 산업기술연구소 1997 논문집 Vol.29 No.1

최근 광 증폭기의 개발로 광통신에서 광전력의 크기는 조절이 가능하나 전송속도를 크게하기 위해서는 광 변조시 발생하는 처핑을 최소화 해야 한다. 본 논문에서는 10Gbit/s급 광통신 시스템을 위한 광 흡수 변조기를 설계하고 그 특성을 고찰하였다. 흡수층 구조는 대역폭, 구동전력 대 소광비 효율, 그리고 편광손실을 모두 고려하여 결정하여야 한다. 1.46㎛ 밴드갭 파장을 갖는 흡수층의 경우 10dB/V이상의 소광비와 10GHz이상의 대역폭, 그리고 20dB 소광비에서 1.75dB이하의 편광손실을 얻을 수 있었다. Recently, the development of optical amplifier allows the optical power control in optical communication system. But still the minimum chirped lightwave signals during optical modulation are required for high data rate optical transmission systems. This paper describes the design of electroabsorption modulators for 10Gbit/s optical communication systems, and analyzes its operating characteristics. The bandwidth, the extinction ratio per unit voltage and the polarization loss were considered simultaneously to obtain the optimum absorption layer structure. The modulation efficiency over 10dB/V, the bandwidth over 10GHz and the polarization loss of 1.75dB at 20dB extinction were achieved with an absorption layer of 1.46㎛ bandgap.

신경망과 TDL 구조에 의한 신호예측

이호섭,김태원,최한고,이상재 金烏工科大學校 1997 論文集 Vol.18 No.-

Neural networks have the potential in the adaptive prediction of nonstationary time series by virtue of the distributed nonlinearities and the learnings ability. This paper describes the adaptive prediction using the cascade combination of nonlinear and linear modulus. Recurrent neural networks (RNNs) and conventional tapped-delay-line (TDL) filter are used as the nonlinear and linear models respectively. For the relative comparison of prediction performance, the proposed predictor was compared with the RNN-based predictor. Simulation results show that the proposed predictor with smaller number of system weights performs better than the RNN-based predictor. We also found that it was well applicable for the prediction of the time series which contains large variations of signal amplitude.

융기 및 테일보이드 폐합효과를 고려한 실드터널의 거동해석

진치섭,한상중 釜山大學校生産技術硏究所` 1998 生産技術硏究所論文集 Vol.54 No.-

실드 터널공법은 연약지반이나 붕괴성 지반에 매우 유리한 터널공법이므로 날로 그 사용이 증대되고 있다. 실드터널을 유한요소법으로 해석할 경우에는 초기 융기와 테일 보이드 폐합에 의한 효과를 고려하여야 한다. 본 연구에서는 Mohr-Coulomb 항복기준을 적용하여 개발한 2차원 탄·점소성 유한요소 프로그램을 이용하여 실드터널의 융기 및 테일보이드 폐합효과를 고려한 해석을 하였으며, 지반교란에 따른 장기거동은 고려하지 않았다. 해석 대상은 N-2 터널로서 실드 막장에서의 압력이 다른 2개의 계측라인에 대하여 계측치와 비교하였다. 융기, 테일보이드 폐합 및 세그먼트 설치 후의 지반거동에 대한 해석결과가 계측치와 유사한 형상을 나타내고 있으므로, 막장압력의 변화에 따른 융기조절로 지반거동에 대한 시공관리를 할 수 있을 것이다. The use of shield is increasing day by day, because it is advantageous tunneling method to the soft and collapsible ground. In case of analyzing shieldfunnel by FEM, behavior of ground due to initial heaving and tail void closure must be considered. In this paper 2 dimensional elasto·viscoplastic finite element analysis program was made using Mohr-Coulomb yield criterion for the shield tunnel considering effects of initial heaving and tail void closure, but not considered long term behavior of ground due to disturbance. The object of analysis was N-2 Tunnel, the numerical values were compared with the measured values that the bulkhead earth pressure is different in 2 instrumentation lines. Since the results of analysis are similar to the measured behavior of ground for heaving, tail void closure and liner installation, therefore the control of construction for the ground behavior can be made by the control of heaving due to variation of bulkhead earth pressure.

스프레드시트와 Green 정리를 이용한 철근 콘크리트 단주의 해석 및 설계

진치섭,한상중,엄장섭,이승훈 釜山大學校生産技術硏究所 1998 生産技術硏究所論文集 Vol.55 No.-

구조물 설게에서, 압축과 2축 휨을 동시에 받는 기둥 설계를 자주 접하게 된다. 이러한 부재의 해석과 설계는, 모멘트 평형에 따른 여러 변수들의 값을 동시에 구하기 위하여 반복적인 작업이 필요하기 때문에 많은 시간을 요구한다. 본 연구에서는 압축과 2축 휨을 받는 철근 콘크리트 단주를 해석 및 설계할 수 있는 컴퓨터 프로그램 COL2를 개발하였다. 프로그램 COL2는 스프레드시트 프로그램 중의 하나인 엑셀을 이용한 사용자 위주 환경의 프로그램으로 개발되었다. Green정리를 사용하여 임의 형상의 역학적 특성을 계산하였다. In structural design, columns subjected to combined compression and biaxial bending are frequently encountered. The analysis and design of such members, are both time consuming and demanding because an iterative procedure is reuqired in order to simultaneously evaluate a number of variables to achieve moment equilibrium. A computer program COL2 is developed to analyze and design reinforced concrete short columns subjected to combined compression and bizxial bending in this study. The program COL2 has been developed for user-friendly environment using MS-Excel one of the spreadsheets program. The mechanical properties of generic shapes was calculated by Green's theorem.

LabVIEW를 이용한 전력품질 분석기술 교육용 웹기반 e-learning 시스템 구현

홍상은,심필섭,한장이 순천향대학교 부설 산업기술연구소 2005 순천향 산업기술연구소논문집 Vol.11 No.2

In this paper, we focused on the implementation of e-learning system for training of power distribution operators in Power Company. And also this paper presents Web-based system for electric power quality analysis based on the LabVIEW approach to enhance streaming of live data and to facilitate the interaction on the PC platform The recent growth in the use of impactive nonlinear loads, electronic and medical devices with sensitiveness to power quality has caused many power quality problems and power supply-and-demand problem. Therefore, the proposed system can also support the solution tool for field operators in the various power quality problems.

Lactobacillus casei YIT9018로부터 분리ㆍ정제한 Whole Peptidoglycan의 In Vitro 항종양활성

金昌漢,李明燮,高時煥,朴相瑨,朴圭炫,白永振 건국대학교 생명과학연구원 1995 생명과학지 Vol.2 No.-

In vitro antitumor activity of whole peptidoglycan(WPG) purified from Lactobacillus casei YIT9018 was examined by clonogenic assay. WPG had antitumor activity against five human tumor cell lines and three mouse tumor cell lines. Antitumor activity of WPG against human tumor cell lines such as A-427, SKMES-1, SF-188, FARROW and RAJI was observed at 300, 1,000, 600, 800 and 900㎍/ml concentration, respectively. Antitumor activity of WPG against mouse tumor cell lines such as 3LL, S-180 and P388 was observed at 100, 500 and 1,000㎍/ml concentration, respectively.

Lactobacillus casei YIT 9018로부터 분리·정제한 Cell Wall Skeleton의 In Vitro 항종양 활성

金昌漢,李明燮,高時煥,朴相瑨,高明秀,白永振 건국대학교 1995 學術誌 Vol.39 No.2

In vitro antitumor activity of cell wall skeleton(CWS) purified from Lactobacillus casei YIT 9018 was examined by clonogenic assay. CWS had antitumor activity against six human tumor cell lines and three mouse tumor cell lines. Antitumor activity of CWS against human tumor cell lines such as A-427, SKMES-1, SF-188, FARROW, RAJI and HEP-2 was observed at 300,800,400,700,900 and 1,000μg/ml concentration, respectively. Antitumor activity of CWS against mouse tumor cell lines such as 3LL, S-180 and P388 was observed at 50,500 and 900μg/ml concentration, respectively. Key words : Lactobacillus casei YIT 9018, Cell Wall Skeleton, Antitumor Activity, Clonogenic Assay

인지기능과 사건관계 전위

이성훈,이종섭,한은선,유계준 大韓神經精神醫學會 1990 신경정신의학 Vol.29 No.4

Event related potential(ERP) were measured in thirty one normal controls(32.9±6.3 in average age), while two kinds of stimuli, frequent and infrequent stimuli were given with an instruction(for counting infrequent stimuli), without an instruction. The amplitudes on N1, P2, P3 were significantly higher with infrequent stimuli than with frequent stimuli in ignoring condition. In instructed condition, the significantly higher amplitudes in P1, N1, P3 components were noted with infrequent stimuli than with frequent stimuli. The amplitude of P3 increased most prominently in an attending condition comparing to an ignoring condition. Good performers of this task showed significantly higher amplitudes in N1 and P3 than bad performers.