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천해에서 내부파로 인해 생성되는 잔향음에 의한 허위표적 신호 발생 가능성
이성춘,김선효,최지웅,강돈혁,박정수,박경주,Lee, Sung Chun,Kim, Sunhyo,Choi, Jee Woong,Kang, Donhyug,Park, Joung Soo,Park, Kyeongju 한국음향학회 2015 韓國音響學會誌 Vol.34 No.2
능동소나 시스템에서 천해 내부파에 의한 잔향음으로부터 유도될 수 있는 허위 표적 신호의 발생 가능성에 대하여 연구하였다. 내부파로부터 굴절된 하향 음선은 강한 해저면 잔향음 신호를 발생시켜 허위 표적 신호를 야기한다. 음원으로부터 송출된 음파는 3차원적으로 전파하므로, 2차원(r-z) 뿐만 아니라 수평방향에 대해서도 고려되어야 한다. 솔리톤(soliton)으로 구성된 내부파 모델링은 음원과 솔리톤간 거리 및 솔리톤의 수평폭과 같이 다양한 조건에서 수행되었다. 음원은 가변심도소나(VDS: Variable Depth Sonar)를 가정하여 모의 환경에서의 최소음속층에 위치시켰고, 음선 기반의 잔향음 모델을 이용하여 시간에 따른 잔향음 준위를 모의하였다. 결과적으로 음원과 솔리톤간 거리 및 솔리톤의 수평폭에 따라 여러 개의 허위표적 신호가 동시에 PPI(Plan Position Indicator) 전시기에 나타날 수 있음을 확인하였다. It is investigated that there exists the possibility of the false target signals induced by reverberation in an active sonar system due to the internal waves in shallow water. The rays down-refracted from the internal waves may generate strong bottom-reverberation signals, which can result in false target signals. Sound waves emitted from a source propagate 3-dimensionally. Therefore, the study of internal waves on the reverberation should be studied for azimuthal direction as well as 2-dimensional (r-z) plane. Internal-wave modelling was conducted, based on solitons which were predicted with the various conditions such as, the range of source-soliton, horizontal widths of soliton. Variable depth sonar (VDS) was assumed as a source, of which the depth was located in the minimum sound speed layer in a simulation environment. Finally, the simulation on the reverberation level with time was made based on ray-based reverberation model, and the results implied that several false-target signals could be displayed on the PPI(Plan Position Indicator) scope simultaneously with range from source to soliton, and the horizontal width of soliton.
이성춘(Sung Chun Lee),김완순(Wan Soon Kim) 한국원예학회 2012 원예과학기술지 Vol.30 No.4
This study was conducted to investigate the physiological and structural damages to cadmium (Cd) in Acorus calamus var. angustatus as a native aquatic species in Korea. In addition to the physiological responses such as plant growth, photosynthesis, and root activity, the structural damages in leaf and root tissues were observed through light and scanning electronic microscopy. The five-leaf plants were treated with different Cd concentrations 0, 10, 25, and 50 μM for 15 days. The plant damages to Cd were significant at 10-25 μM Cd physiologically and at 25-50 μM Cd structurally. The physiological damages in the shoot part (photosynthesis) started at 10 μM Cd whereas those in root part (root activity) were serious above 25 μM Cd. On the other hand, the structural damages began at 25 μM Cd in the leaf and root tissues similarly, but the plant tissue destruction was more serious in the roots than in leaves. Based on the plant physiological and structural damages, 10 μM was assumed to be the limited concentration for sustainable growth and landscaping ability in Acorus calamus var. angustatus to Cd.
자생 수생식물 노랑꽃창포와 창포의 카드뮴 축적 및 내성
이성춘(Sung Chun Lee),김완순(Wan Soon Kim) 한국원예학회 2011 원예과학기술지 Vol.29 No.5
This study was conducted to find out the cadmium (Cd) accumulation and tolerance of Iris pseudacorus and Acorus calamus as aquatic plants native to Korea for Cd removal in water. In the range of Cd concentration from 10 μM to 130 μM, the Cd lethal dose 50 (LD<SUB>50</SUB>) was 78.5 μM in I. pseudacorus and 47.6 μM in A. calamus. In I. pseudacorus, superoxide dismutase and peroxidase as antioxidants were relatively effective against oxidative stress caused by Cd, while catalase, superoxide dismutase, and polyphenolics were effective in A. calamus. The polyphenolics known as typical antioxidants were not detected in I. pseudacorus. In both species, the Cd accumulation in plants increased with the higher Cd concentration and the longer processing period. Also, the absorbed Cd was accumulated mainly in the roots. The amount of Cd accumulated in the shoot part was maximally 548.1 mg?kg<SUP>-1</SUP> (82.1% to Cd accumulated in the root part) in I. pseudacorus and 121.4 mg?kg<SUP>-1</SUP> (13.7%) in A. calamus, which implied that both species all were enough evaluated as Cd hyper-accumulators based on 0.01% or more Cd accumulation in the shoot. Especially I. pseudacorus showed outstanding ability to move well Cd into the shoots from the roots and high tolerance to Cd stress.
이성춘(Sung Chun Lee),이정식(Jeong Sik Lee),정순진(Sun Jin Jeong) 한국원예학회 2005 원예과학기술지 Vol.23 No.4
This experiment was conducted to find out the optimum number of bud and medium composition on plant survival and growth in division of Acorus calamus for mass propagation by evaluating two kinds of bud number, 1 and 3, and three kinds of mixed media, peat moss 1 + vermiculite 1 + perlite 1 (v/v/v), vermiculite 1 + perlite 1 (v/v), and peat moss 1 + perlite 1 (v/v). After 25 days from division date, the new root came out. Plant height and plant width, leaf number and new bud number were the best from 6 to 10 weeks from division in the mixed media of peat moss 1 + vermiculite 1 + perlite 1 and peat moss 1 + perlite 1 regardless of bud number at the division time. The survival was 100% in all plots. In the early plant growth, fresh and dry weight from division, plot of three buds were better than one bud, but plant growth was the best in the media of peat moss 1 + vermiculite 1 + perlite 1 and peat moss 1 + perlite 1 regardless of bud numbers.
플러그 셀의 크기 및 배지 조성에 따른 물억새의 발아율과 생장
이성춘(Sung Chun Lee),이정식(Jeong Sik Lee),정순진(Sun Jin Jeong) 한국원예학회 2005 원예과학기술지 Vol.23 No.3
This experiment was conducted to find out the optimum plug cell size and medium composition on germination and seedling growth of Miscanthus sacchariflorus for mass propagation. This study was evaluated in 3 plug cell sizes (128, 200, and 288) and 3 mixed media (peat moss 1 + vermiculite 1 + perlite 1 (v/v/v), vermiculite 1 + perlite 1 (v/v), and peat moss 1 + perlite 1 (v/v)). Seeds of Miscanthus sacchariflorus sowed on June 30, 2004. The germination percentage was highest at peat moss 1 + perlite 1 (v/v), 200 plug cell tray and the average germination percentage was below 50%. Seedling growth was excellent in the medium of peat moss 1 + perlite 1 (v/v). New branch from seedling was formed at peat moss 1 + perlite 1 (v/v) only.