용매 증발법에 의한 $Pb(Mg_{1/3}Nb_{2/3})O_3$ 분말 합성 및 유전 성질

이종필,이종국,강상구,김환,Lee, Jong-Pil,Lee, Jong-Kook,Kang, Sang-Gu,Kim, Hwan 한국세라믹학회 1996 한국세라믹학회지 Vol.33 No.1

Pb(Mg1/3Nb2/3)O3 powder with high purity chemical homogeniety and reactivity was prepared by solvent eva-poration of common solution. The common solution was fabricated using a Pb(NO3)2 Mg(NO)3 and NB solution which was prepared by dissolving NbC in H2O2 acquous solution. In precusor powder prepared by solvent evaporation method the synthetic temperature of Pb(Mg1/3 Nb2/3)O3 phase was lowered. And the formation of homogeneous Pb(Mg1/3Nb2/3)O3 phase was enhanced but the formation of pyrochlore phase was reduced. The dielectric constant of PMN ceramics from the synthesized powder was found to increase with both sintering temperature and excess MgO and subsequent analysis of the microstructures confirmed that this was due to an increase in grain size. The grain size dependence is explained as a consequence of low-permittivity grain boundaries.

50G/T급 FRP어선 건조 소개

이종필,Lee, Jong-Pil 선박안전기술공단 1980 漁船 Vol.5 No.-

3차원 펄스 레이다 시험용 타이밍 신호 발생기 구현

이종필,이일근,금현주,Lee, Jong-Pil,Rhee, Ill-Keun,Kim, Hyoun-Ju 한국전기전자학회 2005 전기전자학회논문지 Vol.9 No.2

본 논문에서는 3차원 레이다 시험용 타이밍신호 발생기를 개발하였다. 개발된 발생기는 모의표적신호에 고각 정보를 모의할 수 있는 기능을 갖추었고, 내부에 구상변조 기능을 가지고 있어 80MHz까지의 변조된 신호를 발생할 수 있다. 또한 기저대역신호를 외부에서 입력받아 중간주파수로 변환하는 과정을 보드 내에서 처리가 가능하므로 다양한 시험환경을 쉽게 구현할 수 있고 별도의 파형합성기가 필요 없어 저렴한 비용으로 레이다 시험장비 구성이 가능하다. 아울러 운용프로그램에 따라 쉽게 파라미터를 변경할 수 있는 충분한 메모리를 내장하고 있어 시험환경을 변경할 필요가 있을 때 시간 및 비용을 절감할 수 있다. This paper describes some major schemes for developing timing signal generator which can be used for testing of 3D radars. The developed generator has a function not only to simulate information on elevation angle for the simulated target signals but also to generate a modulated signal up to 80MHz. Because this generator has an internal modulating function instead of an external modulating function and has sufficient memory enough to change the parameters according to operating programs, it realization of various test-environments for testing a radar can be made with easy and with low expense.

FRP선 건조에 관하여

이종필,Lee, Jong-Pil 선박안전기술공단 1980 漁船 Vol.4 No.-

디스크형 압전변압기의 전극 면적비에 따른 구동 메카니즘에 관한 연구

이종필,채홍인,홍진웅,Lee, Jong-Pil,Chae, Hong-In,Jin, Woong-Hong 한국조명전기설비학회 2005 조명·전기설비학회논문지 Vol.19 No.5

본 연구에서는 직경이 50[mm], 두께가 4.5[mm]인 디스크형 압전 변압기의 구동부와 발전부의 전극 면적비를 각각 1.4:1, 2:1 및 3:1로 분할하여, 부하 저항을 변화(100${[\Omega]}\~70{[k\Omega]}$)시키면서 전기적 특성을 측정하고, 이를 토대로 한 압전변압기의 승압비에 관한 메카니즘을 정량적 및 정성적으로 해석하였다. In this study, a disk-type piezoelectric transformer was fabricated. Its diameter was 50[mm] and thickness was 4.5[mm]. The driving and generating electrode with their gap of 1[mm] were fabricated on the top surface. But the common electrode was fabricated on the whole bottom surface. The electrode surface ratio of driving and generating part on the top surface was the range of 1.4:1 to 3:1. We investigated the electrical characteristics with the variation of its thickness and the electrode surface ratio of driving and generating part in the range of load resistance of 100${[\Omega]}\~70{[k\Omega]}$.. Form the experimental results, their influence on the set-up voltage ratio were investigated quantitively and qualitatively.

새로운 통신전원용 3상 AC-DC Flyback 컨버터

이종필,최주엽,송중호,최익,김택용,윤태웅,Lee, Jong-Pil,Choi, Ju-Yeop,Song, Joong-Ho,Choy, Ick,Kim, Taek-Yong,Yoon, Tae-Woong 전력전자학회 1999 전력전자학회 논문지 Vol.4 No.2

본 논문에서는 우수한 출력전압 조절 기능과 높은 역률을 갖는 3상 AC-DC flyback 컨버터를 제안한다. 제안한 컨버터의 장점은 보통 부스트 형의 3상 컨버터에서 쓰이는 가격이 비싼 고전압, 대전류의 소자를 필요로 하지 않는다. 본 논문에서는 제어 목적으로 3상 AC-DC flyback 컨버터에 대해서 소신호 해석을 하였고 실험결과는 분석의 타당성을 확증한다. Three-phase AC-DC flyback converter with high power factor correction and tight regulation is presented in this p paper. The advantage of the proposed converter does not require expensive high voltage and high cun‘ent devices that a are normally needed in popular boost type 3-phase converter. In this paper the detailed small signal analysis of the m modular 3-phase AC-DC flyback converter is provided for control purposes and also experimental results are included t to confirm the validity of the analysis.

평면파를 이용한 초음파 합성 송신 집속 기법의 해석

이종필,송재희,송태경,Lee, Jong Pil,Song, Jae Hee,Song, Tai-Kyong 한국음향학회 2014 韓國音響學會誌 Vol.33 No.3

본 논문에서는 평면파 합성 송신집속 방법의 모델을 제시하고 수학적 해석을 통해 그 특성을 분석하였으며 일반적인 구형파 기반의 집속 방법과 비교하였다. 이를 통하여 평면파를 이용한 합성 송신집속 방법은 거리에 따라 주엽의 폭이 변하지 않는 비회절 빔을 발생함을 확인하였다. 또한 그레이팅 로브의 발생을 억제하며 원하는 주엽 폭을 얻기 위한 평면파 합성 방법, 그리고 비회절 특성이 유지되는 영역을 효과적으로 확장시킬 수 있는 방법을 제시하였다. 제안된 방법과 해석결과들을 컴퓨터 모의실험을 통해 검증하였다. In this paper, we present a general model for synthetic transmit focusing method using plane waves (STF-PW) of which the properties are investigated through mathematical analysis and compared with those of the conventional focusing method. The analysis results show that STF-PW produces non-diffracting beams in the sense that their main lobe widths do not change with depth. We also present a method for synthesis of plane waves to obtain a desired main lobe width while preventing grating lobe generation and a method for broadening the region over which the non-diffracting property is maintained. The proposed model and analysis results were validated through computer simulations.

분말야금 스테인리스 스틸의 산화특성에 미치는 조성 및 조직변화의 영향

이종필,홍지현,박동규,안인섭,Lee, Jong-Pil,Hong, Ji-Hyun,Park, Dong-Kyu,Ahn, In-Shup 한국분말야금학회 2015 한국분말재료학회지 (KPMI) Vol.22 No.1

As well-known wrought stainless steel, sintered stainless steel (STS) has excellent high-temperature anti-corrosion even at high temperature of $800^{\circ}C$, and exhibits good corrosion resistance in air. However, when temperature increases above $900^{\circ}C$, the corrosion resistance of STS begins to deteriorate and dramatically decreases. In this study, the effects of phase and composition of STS on high-temperature corrosion resistances are investigated for STS 316L, STS 304 and STS 434L above $800^{\circ}C$. The morphology of the oxide layers are observed. The oxides phase and composition are identified using X-ray diffractometer and energy dispersive spectroscopy. The results demonstrate that the best corrosion resistance of STS could be improved to that of 434L. The poor corrosion resistance of the austenitic stainless steels is due to the fact that $NiFe_2O_4$ oxides forming poor adhesion between the matrix and oxide film increase the oxidation susceptibility of the material at high temperature.

STS 316L 소결체의 부식 저항 특성에 미치는 금속산화물 첨가의 영향

이종필,홍지현,박동규,안인섭,Lee, Jong-Pil,Hong, Ji-Hyun,Park, Dong-Kyu,Ahn, In-Shup 한국분말야금학회 2015 한국분말재료학회지 (KPMI) Vol.22 No.4

As wrought stainless steel, sintered stainless steel (STS) has excellent high-temperature anti-corrosion even at high temperature of $800^{\circ}C$ and exhibit corrosion resistance in air. The oxidation behavior and oxidation mechanism of the sintered 316L stainless was reported at the high temperature in our previous study. In this study, the effects of additives on high-temperature corrosion resistances were investigated above $800^{\circ}C$ at the various oxides ($SiO_2$, $Al_2O_3$, MgO and $Y_2O_3$) added STS respectively as an oxidation inhibitor. The morphology of the oxide layers were observed by SEM and the oxides phase and composition were confirmed by XRD and EDX. As a result, the weight of STS 316L sintered body increased sharply at $1000^{\circ}C$ and the relative density of specimen decreased as metallic oxide addition increased. Compared with STS 316L sintered parts, weight change ratio corresponding to different oxidation time at $900^{\circ}C$ and $1000^{\circ}C$, decreased gradually with the addition of metallic oxide. The best corrosion resistance properties of STS could be improved in case of using $Y_2O_3$. The oxidation rate was diminished dramatically by suppression the peeling on oxide layers at $Y_2O_3$ added sintered stainless steel.

과도안정도 해석을 위한 지능형 부하모델의 새로운 접근법

李鍾弼(Jong-Pil Lee),林裁尹(Jae-Yoon Lim),池平植(Pyeong-Shik Ji) 대한전기학회 2008 전기학회논문지 P Vol.57 No.2

The field of load modeling has attracted the attention since it plays an important role for improving the accuracy of stability analysis and power flow estimation. Also, load modeling is an essential factor in the simulation and evaluation of power system performance. However, conventional load modeling techniques have some limitations with respect to accuracy for nonlinear and composite loads. Thus, precision load modeling technique and reasonable application method is needed for more accurate power system analysis. In this paper, we develop an intelligent load modeling method based on neural network and application techniques for power system. The proposed method makes it possible to effectively estimate the load model for nonlinear models as well as linear models. Reasonable application method is also proposed for stability analysis. To demonstrate the validity of the proposed method, various experiments are performed and their results are presented.