미기록 귀화식물: Plantago aristata (Plantaginaceae)

이정호,한동욱,이은주,박종욱,Lee, Jungho,Han, Dong Uk,Lee, Eun Ju,Park, Chong-Wook The Korean Society of Plant Taxonomists 2005 식물 분류학회지 Vol.35 No.2

절경이과의 Plantago aristata Michx.(국명신칭: 긴포꽃질경이)가 경기도 고양시 한강하구에 자라고 있는 것으로 처음 확인되었다. 이 귀화식물은 선형인 잎(길이 9-20 cm, 폭 5-8 mm), 긴 선형의 포(길이 약 2.5 cm), 큰 흰꽃(직경 4-6 mm)으로 다른 한반도 질경이속 식물들과 구별된다. 북미 원산인 본 종은 인근 국가인 일본과 중국에도 유입되어 퍼져나가고 있는 것으로 보고되어 있다. 확증표본은 서울대학교 석엽표본관(SNU)에 소장하였다. We reported that an alien species of Plantaginaceae, Plantago aristata Michx. from North America, grows at the Han-River estuary in Go-Yang City, Kyunggi Province. This species is easily distinguished from others in Korea by its linear leaves, cylindrical spikes with long linear bracts at base, and relatively large flowers of ca. 4-6 mm in diameter. We called the species as gin-po-ggot-jil-kyung-i as a local name. Plantago aristata is known to be very invasive and has been already introduced to Japan and China.

Vernier 신호 분석에서 자기상관함수 기반의 후처리를 이용한 주파수선 음향징표 특징 강화

이정호,배건성,Lee, Jungho,Bae, Keunsung 한국정보통신학회 2013 한국정보통신학회논문지 Vol.17 No.3

본 연구에서는 수동소나 신호의 분석에서 얻어지는 토널 성분, 즉, 주파수선의 하모닉 성분을 강화하는 새로운 방법을 제안하였다. 제안한 방법에서는, 먼저 스펙트럼의 일정 시간에 따른 주파수 빈별 평균값을 구하고, 평균값과의 차이를 이용하여 안정적인 주파수선과 불안정한 주파수선을 구별한다. 그런 다음 불안정한 주파수선에 자기상관함수와 S2PM을 적용하여 배경잡음을 줄이고 하모닉 성분을 강조하게 된다. 실제 어선에서 획득한 수중음향 데이터를 이용한 실험 결과를 분석하였고, 이를 통해 제안한 방법의 타당성을 검증하였다. In this paper, we propose a novel method to enhance the harmonic components from the frequency lines of the passive sonar signals. For this, we first separate the stable frequency lines from unstable ones using mean and difference of spectral bins in the vernier analysis. Then we emphasize the harmonic components using autocorrelation-based postprocessing, and enhance them by reducing the background noise with the split-window two pass mean algorithm. Experimental results for real underwater acoustic data are presented with our discussions.

운동량 플럭스 비의 변화에 따른 기체 중심 스월 동축형분사기의 기체 가진 동특성 연구

이정호 ( Jungho Lee ),박구정 ( Gujeong Park ),윤영빈 ( Youngbin Yoon ) 한국액체미립화학회 2015 한국액체미립화학회지 Vol.20 No.3

Combustion instability is critical problem in developing liquid rocket engine. There have been many efforts to solve this problem. In this study, the method was sought through the injector as part of these efforts to suppress combustion instability. If the injector can suppress the disturbance coming from the supply line as a kind of buffer it will serve to reduce combustion instability. Especially we target at gas propellant oscillation in gas-centered swirl coaxial injector. The phenomenon is simulated with acoustic excitation of speaker. The film thickness response at injector exit was measured by using a liquid film electrode. Also the response of spray to the disturbance was observed by high-speed photography. Gas-liquid momentum flux ratio and the frequency of feeding gas oscillation were changed to investigate the effect of these experimental parameters. The trend of response by varying these parameters and the cause of weak points was studied to suggest the better design of injector for suppressing combustion instability.

전압방정식과 적분 계산을 이용한 정지상태에서의 유도전동기 상호 인덕턴스 추정 방법

이정호(Jungho Lee),지진우(Jinwoo Ji),이상훈(Sanghoon Lee) 대한전기학회 2023 대한전기학회 학술대회 논문집 Vol.2023 No.5

엔진 연소시험 추진제 입구 온도센서 측정값 고찰

이정호(Jungho Lee),우성필(Seongphil Woo),전준수(Junsu Jeon),임지혁(Jihyuk Im),유병일(Byungil Yoo),김승한(Seunghan Kim),한영민(Yeoungmin Han) 한국추진공학회 2020 한국추진공학회 학술대회논문집 Vol.2020 No.11

완전 난류 충돌제트의 국소 및 평균 열전달 특성

이정호(Jungho Lee),김서현(Seo Hyun Kim),도규형(Kyu Hyung Do) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.10

The local and average heat transfer characteristics by a fully-turbulent jet were experimentally investigated for an axisymmetric submerged air jet impinging on normal to a heated flat plate. The heat transfer was measured by consecutively installed thermocouples beneath a heated flat surface. The experiment was performed at 9 different fully-turbulent jets and 6 different nozzle-to-plate spacings. The stagnation Nusselt number was significantly varied by the nozzle-to-plate spacing and was also correlated with the jet Reynolds number and the nozzle-to-plate spacing. The uncertainty analysis based on the ANSI/ASME PTC 19.1-2005 standard was additionally carried out to provide more quantitative heat transfer results.

액적 열전달 향상에 미치는 Dissolved 가스의 영향에 관한 연구

이정호(Jungho Lee),Jungho Kim,Kenneth T. Kiger 대한기계학회 2003 대한기계학회 춘추학술대회 Vol.2003 No.4

Droplet evaporation can be used to transfer large amounts of energy since heat is transferred across a thin<br/> liquid film. Spreading the drop over a larger area can enhance this heat transfer. One method of accomplishing<br/> this is to dissolve gas into the liquid. When the drop strikes the surface, a gas bubble nucleates and can grow<br/> and merge within the liquid, resulting in an increase in the droplet diameter. In this study, time and space resolved<br/> heat transfer characteristics for a single droplet striking a heated surface were experimentally investigated.<br/> The local wall heat flux and temperature measurements were provided by a novel experimental technique<br/> in which 96 individually controlled heaters were used to map the heat transfer coefficient contour on the<br/> surface. A high-speed digital video camera was used to simultaneously record images of the drop from below.<br/> The measurements to date indicate that significantly smaller droplet evaporation times can be achieved. The<br/> splat diameter was observed to increase with time just after the initial transient dies out due to the growth of<br/> the bubble, in contrast to a monotonically decreasing splat diameter for the case of no bubbles. Bursting of the<br/> bubble corresponded to a sudden decrease in droplet heat transfer.

우리나라 주요 침엽수종의 최적 경쟁지수 모형 선정

이정호 ( Jungho Lee ),이대성 ( Daesung Lee ),서영완 ( Yeongwan Seo ),최정기 ( Jungkee Choi ) 한국산림과학회(구 한국임학회) 2018 한국산림과학회지 Vol.107 No.2

본 연구는 국내 주요 침엽수종인 소나무, 잣나무, 낙엽송을 대상으로 거리종속 경쟁지수 모델 및 경쟁목 선정방법에 따른 최적 경쟁지수 모형을 선발하고, 수종별 간벌강도 및 입목밀도에 따른 경쟁지수 특성을 분석하고자 하였다. 사용자료는 강원도와 경상북도의 국유림 내 분포하는 소나무림, 잣나무림, 낙엽송림을 대상으로 각 2회씩 조사된 표준지 80개소의 총 240개 시험구 내 입목정보를 활용하였다. 경쟁지수가 산출된 입목 수는 수종별로 소나무 1126본, 잣나무 4093본, 낙엽송 3399본 이었다. 최적 경쟁지수 모형 선정을 위하여 흉고단면적 정수, 수고 및 지하고의 각도를 이용하여 경쟁목을 선정하는 방법을 고려하였으며, 기존 Lorimer, Martin-EK, Braathe, Heygi, Daniels 모델과 본 연구에서 제안한 Modified Daniels 모델까지 총 6가지 경쟁지수 모델을 비교하였다. 최적 모형 선정을 위한 상관분석 결과, 흉고단면적 정수 4 m²/ha를 이용한 경쟁목 선정방법과 Modified Daniels 경쟁지수 모델이 이용된 모형에서 가장 좋은 상관이 나타나 최종적인 모형으로써 경쟁지수가 산출되었다. 임분특성에 따른 경쟁지수를 파악한 결과, 소나무, 잣나무, 낙엽송 모두 간벌강도가 강할수록 입목밀도가 낮을수록 경쟁지수는 낮아지는 경향이 나타났다. This study was carried out to select the optimal method of competition index computation according to the competitor selection methods and distant-dependent competition index models, and to analyze the characteristics of competition indices in terms of thinning intensity and tree density targeting Pinus densiflora, Pinus koraiensis, and Larix kaempferi, which are the major coniferous species in Korea. Data was the re-investigated tree information from 240 permanent plots of 80 sites in the stands of P. densiflora, P. koraiensis, and L. kaempferi, which were located in the national forest of Gangwon and North Gyeongsang provinces. The number of subject trees with competition index calculated were 1126 trees for P. densiflora, 4093 trees for P. koraiensis, and 3399 trees for L. kaempferi. For the best competition index computation method, three kinds of competitor selection methods were considered: basal area factor, angle of height, angle of height to crown base. Also, six kinds of competition index models were compared: Lorimer, Martin-EK, Braathe, Heygi, Daniels, and Modified Daniels, which was developed in this study. Correlation coefficient was the best when the competitor selection method of basal area factor 4 m²/ha and the competition index model of Modified Daniels were used, and thus, it was selected as the best method for computing competition index. According to the best method by stand characteristics, competition index decreased in all species as thinning intensity was high and tree density was low.

Auto Section Control Module 개발 연구

이정호(Jungho Lee),강동규(Dongkyu Kang),유봉선(Bongsun Ryu) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

At present, the paradigm of the design and manufacturing process in the manufacturing industry is being changed rapidly. Also a new 3D Tooling Process is being prepared through the positive development of new technologies, including VM, to support ONE-STOP-PROCESS in the manufacturing process. Therefore, it is necessary to develop a new control module through a radical reform, including the conversion of Thinking and Method. In the end, Auto Section Control Module been developed by considering the effective user interface and the complete connection with CATIA V5. We can achieve high quality of stamping dies in the short time, and improve the manufacturing process of stamping die.

대용량 유량측정의 불확실성 해석

이정호(Jungho Lee),박상진(Sang-Jin Park),윤석호(Seok Ho Yoon) 한국유체기계학회 2008 유체기계 연구개발 발표회 논문집 Vol.2008 No.-

Measurement uncertainty of high flow rate has been estimated by a quantitative uncertainty analysis which is based on the ANSI/ASME PTC 19.1-1985 standards. The best way to reduce error in measuring flow rate was investigated for evaluating its measurement uncertainty. The representative methods for measuring high flow rate using venturi, flow nozzle and orifice were compared with their measurement characteristics. The main factor which affects the flow rate measurement was revealed to minimize the pressure loss in the flow. The major parameters for causing errors in flow rate measurement were the differential pressure and discharge coefficient, respectively and the additional parameters were turbulent intensity, flow swirling, degree of convergent angle, and change of static holes.