• 자연과학논문집
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• 제11권1호
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• pp.137-142
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• 1999

미국 J.C. Raulston 식물원에는 한국자생 조경수목 36과 110종 3품종이 재배되고 있다. 이중 때죽나무 'Emerald Pagoda'는 1985년 미국 국립식물원 식물탐사팀과 J.C. Raulston이 소흑산도에서 채집한 우리나라 자생종으로 미국내에서 감상가치가 매우 뛰어난 것으로 평가받고 있다. J.C. Raulston은 이 때죽나무를 'Sohuksan'이라고 명명하였다가 'Emerald Pagoda'로 개칭하였는데 미국으로 수화물에 보관하여 도입하였다. 또한 아왜나무를 진도에서 채집하였는데, 이것은 지금도 'Chindo'라는 품종으로 불리고 있으며 미국내 동남부 지방의 조경에 적응성이 높고 감상가치가 높아 대량번식 및 보급 중에 있다.

• Journal of Biosystems Engineering
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• 제36권1호
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• pp.15-22
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• 2011

An experimental variable rate nursery sprayer was developed to adjust application rates for canopy volume in real time. The sprayer consisted of two vertical booms integrated with ultrasonic sensors, and variable rate nozzles coupled with pulse width modulation (PMW) based solenoid valves. A custom-designed microcontroller instructed the sensors to detect canopy size and occurrence and then controlled nozzles to achieve variable application rates. A spray delivery system, which consisted of diaphragm pump, pressure regulator and 4-cycle gasoline engine, offered the spray discharge function. Spray delay time, time adjustment in spray trigger for the leading distance of the sensor, was measured with a high-speed camera, and it was from 50 to 140 ms earlier than the desired time (398 ms) at 3.2 km/h under indoor conditions. Consequently, the sprayer triggered 4.5 to 12.5 cm prior to detected targets. Duty cycles of the sprayer were from 20 to 34 ms for senor-to-canopy (STC) distance from 0.30 to 0.76 m. Outdoor test confirmed that the nozzles were triggered from 290 to 380 ms after detecting tree canopy at 3.2 km/h. The spray rate of the new sprayer was 58.4 to 85.2% of the constant application rate (935 L/ha). Spray coverage was collected at four areas of evergreen canopy by water sensitive papers (WSP), and ranged from 1.9 to 41.1% and 1.8 to 34.7% for variable and constant rate applications, respectively. One WSP area had significant (P < 0.05) difference in mean spray coverage between two application conditions.