연동펌프를 이용한 비료염 공급 관비재배기술 연구

김동억,이공인,김현환,우영회,이운용,강인철,Kim, D.E.,Lee, G.I.,Kim, H.H.,Woo, Y.H.,Lee, W.Y.,Kang, I.C. 국립한국농수산대학교 교육개발센터 2015 현장농업연구지 = Journal of practical agricultural resear Vol.17 No.1

This study was conducted to develop the fertigation system with a peristaltic hose pump and brushless DC motor. The fertigation system was consisted of sensor, main controller, motor control unit, peristaltic pump, water supply pump, control panel, and filter. The peristaltic pump discharges liquid by squeezing the tube with rollers. Rollers attached to the external circumference of the rotor compresses the flexible tube. The fluid is contained within a flexible tube fitted inside a circular pump casing. The developed fertigation system has no mixing tank but instead injects directly a concentrated nutrient solution into a water supply pipe. The revolution speed of the peristaltic pump is controlled by PWM (Pulse width modulation) method. When the revolution speed of the peristaltic pump was 300rpm, the flow rate of the 3.2, 4.8, 6.3mm diameter tube was 202, 530, 857mL/min, respectively. As increasing revolution speed, the flow rate of the peristaltic pump linearly increased. As the inner diameter of a tube larger, a slope of graph is more steep. Flow rate of three roller was more than that of four roller. Flow rate of a norprene tube with good restoring force was more than that of a pharmed tube. As EC sensor probe was installed in direct piping in comparison with bypass piping showed good performance. After starting the system, it took 16~17 seconds to stabilize EC. The maximum value of EC was 1.44~1.7dS/m at a setting value of 1.4dS/m. The developed fertigation system showed ±0.06dS/m deviation from the setting value of EC. In field test, Cucumber plants generally showed good growth. From these findings, this fertigation system can be appropriately suitable for fertigation culture for crops.

2023년 원자력기기 및 열유체 분야 연구동향

김동억 한국유체기계학회 2024 한국유체기계학회 논문집 Vol.27 No.2

광원과 양액이 상추 생육에 미치는 영향

김동억,김봉수,김현배,김관우,윤용철,최만권,김치호,김현태 경상대학교 농업생명과학연구원 2013 농업생명과학연구 Vol.47 No.3

In this study, targeted lettuce primarily planting in plant factory, LED irradiation time and nutrient composition was conducted to investigate the effect of the growth. Varieties of lettuce used for the analysis is 'Grand Rapids' lettuce. We cultivate the lettuce during five weeks, investigated the optimal nutrient supply methods and lettuce growth after seeding on 7, 14, 21, 27, 35 days, respectively. This finding represents that the Lettuce liquid of Yamajaki was the most pertinent culture liquid for cultivating Grand rapids. On the contrary, the minimum growth level was observed in use of Wondergrow Medium under experimental condition of 12 hr(on)/12 hr(off). 본 연구에서는 식물공장에서 주로 재배하는 상추를 대상으로 LED 조사 시간과 양액조성이 생장에 미치는 영향을 구명하기 위하여 수행하였다. 분석에 이용한 상추의 품종은 공시품종 청축면 상추이다. 상추는 분무경을 이용하여 5주간 재배하며, 정식 후 7, 14, 21, 27, 35일 경과 후 각각 생육조사 및 최적의 양액공급법에 대해 조사하였다. 조사 결과 청축면 상추에 가장 적절한 양액은 야마자키액이라고 판단하였으며, 광조건을 (12 hr(on)/12 hr(off))로 조절하거나 Wondergrow액으로 양액을 조성한 처리에서 생육이 가장 저조하였다.

토양 수분함량이 토마토 묘의 생육 및 항산화 효소에 미치는 영향

김동억,강정균,신윤아,홍순중,이운용,우영회,Kim, D.E.,Kang, J.K.,Shin, Y.A.,Hong, S.J.,Lee, W.Y.,Woo, Y.H. 국립한국농수산대학교 교육개발센터 2019 현장농업연구지 = Journal of practical agricultural resear Vol.21 No.2

본 연구는 토마토 육묘 시 생육과 묘소질에 영향을 줄 수 있는 요인 중에서 수분함량이 모종의 생육과 항산화효소 형성에 미치는 영향, 엽온의 변화에 대한 관찰을 수행하였다. 실험 방법은 토마토 모종을 관수한 상태의 무게가 50g, 40g, 30g가 되도록 관수를 하였고 각 묘 및 트레이의 무게를 시간마다 측정하였으며, 열화상 카메라를 이용하여 엽온을 측정하였고, 실험 후 각 묘의 항산화효소를 측정하여 스트레스 여부를 확인하였다. 실험 결과, 상토 무게의 변화는 주간 감소량 보다 야간의 감소량이 더 적은 것으로 나타났으며 각 묘의 무게별 감소량은 차이가 없는 것으로 나타났다. 또한 상토 무게에 따른 생육 변화도 차이가 없는 것으로 나타났다. 하지만 플라보노이드 및 항산화 효소는 상토 무게 50g에서 가장 높게 나타났다. 이는 근권부에 과습 상태가 장시간 지속되어 스트레스를 받은 것으로 판단되며, 추후 장시간 생육 변화, 실시간 환경 변화 조사 및 상토 종류에 따른 증발산량 조사가 필요할 것으로 사료된다.

웹과 스마트폰 기반의 온실 환경 제어 시스템 개발

김동억,이운용,강동현,강인철,홍순중,우영회,Kim, D.E.,Lee, W.Y.,Kang, D.H.,Kang, I.C.,Hong, S.J.,Woo, Y.H. 국립한국농수산대학교 교육개발센터 2016 현장농업연구지 = Journal of practical agricultural resear Vol.18 No.1

Monitoring and control of the greenhouse environment play a decisive role in greenhouse crop production processes. The network system for greenhouse control was developed by using recent technologies of networking and wireless communications. In this paper, a remote monitoring and control system for greenhouse using a smartphone and a computer with internet has been developed. The system provides real-time remote greenhouse integrated management service which collects greenhouse environment information and controls greenhouse facilities based on sensors and equipments network. Graphical user interface for an integrated management system was designed with bases on the HMI and the experimental results showed that a sensor data and device status were collected by integrated management in real-time. Because the sensor data and device status can be displayed on a web page, transmitted using the server program to remote computer and mobile smartphone at the same time. The monitored-data can be downloaded, analyzed and saved from server program in real-time via mobile phone or internet at a remote place. Performance test results of the greenhouse control system has confirmed that all work successfully in accordance with the operating conditions. And data collections and display conditions, event actions, crops and equipments monitoring showed reliable results.

인공광을 이용한 수경재배에서 배양액 농도가 상추의 생장과 배양액 양분 농도에 미치는 영향

김동억,이운용,허정욱,이공인,강동현,우영회,Kim, D.E.,Lee, W.Y.,Heo, J.W.,Lee, G.I.,Kang, D.H.,Woo, Y.H. 국립한국농수산대학교 교육개발센터 2017 현장농업연구지 = Journal of practical agricultural resear Vol.19 No.1

This study was conducted to investigate the effects of nutrient solution strength on growth and nutrient element concentrations in leaf lettuce (Lactuca sativa L. cv. 'Dduksum') by hydroponic culture under fluorescent lamp and LED. Leaf lettuce were grown in closed hydroponic cultivation systems supplied with 1/2, 1 and 2 strength of nutrient solution recommended by horticultural experiment station in Japan. The growth of 'Dduksum' was highest in the 2 strength of standard nutrient solution. The amount of nutrient element in the recycled nutrient solution was higher at 2, 1 and 1/2 strength of nutrient solution. The concentration of NO₃-N, Ca²⁺, Mg²⁺ in the recycled nutrient solutions increased in 1 and 2 strength of nutrient solution but that of NH₄-N decreased gradually in 1/2 and 1 strength of nutrient solution. The concentration of K, Ca, Mg in leaf lettuce was maintained in the normal range, whereas the concentration of phosphorous was 1.3 to 1.6%, which was higher than proper range. As the concentration of NH₄-N decreases gradually in all the treatments, it is necessary to raise the rate of NH₄-N or add it.

Feedback Linearization Control of Grid-Interactive PWM Converters with LCL Filters

김동억,이동춘 전력전자학회 2009 JOURNAL OF POWER ELECTRONICS Vol.9 No.2

This paper proposes a feedback linearization control scheme of AC/DC PWM converters with LCL input filters using no damping resisters. Feedback linearization techniques use a transformation from nonlinear system models into equivalent linear models in a simpler form. The feedback linearization scheme in this work has cascade structures unlike usual feedback linearization, therefore it has an advantage that it is possible to limit the capacitor current to a certain level. The performance of the proposed controller is validated with simulation and experimental results.

동맥경화 분자영상

김동억,정상욱 대한의사협회 2009 대한의사협회지 Vol.52 No.2

Atherosclerosis is characterized by progressive accumulation of lipids and inflammatory cells within the artery wall. It is a diffuse systemic disease; however, some atherosclerotic plaques are more prone to rupture causing sudden thromboembolic vascular occlusions, while others are clinically silent. Therefore, to prevent such devastating vascular events as stroke or myocardial infarction, clinicians need to have smart tools to localize high-risk vulnerable plaques, which have been a huge challenge to date. Molecular imaging, which visualizes biologic processes at the cellular and molecular level, has a potential to assess plaque vulnerability and consequently identify high-risk patients prior to the development of the clinical events. In this review, we summarize important updates on the molecular imaging of atherosclerosis in the field of optical imaging, magnetic resonance imaging, positron emission tomography, and computerized tomography imaging.

C17.2 신경줄기세포 및 일차 신경줄기세포의 허혈 내성

김동억 대한뇌졸중학회 2006 Journal of stroke Vol.8 No.1

Background: It has not been studied whether neural stem cells (NCSs) have ischemic tolerance phenomenon, which could protect the cells when exposed to non-permissive environments. Methods: C17.2 neural precursor cells (NPCs) and freshly-isolated NPCs growing as neurospheres were used to study: (a) if NPCs survival rate could be decreased by exposing them to in vitro ischemia, and (b) if the survival rate could be improved by a preceding hypoxia of short duration. After a baseline experiment to verify that the cells have characteristics of NSCs, 30 min or 1 hour of ischemia was applied to the cells of the preconditioning-only group and ischemia-after-preconditioning group. Forty eight hours later, 12 or 24 hours of main ischemia was given to the cells of the ischemia-after-preconditioning group and ischemia-without-preconditioning group. Control group cells were incubated under normoxic conditions for equivalent durations. After 2 or 12 hours of reperfusion period, luciferase viability assays, lactate dehydrogenase release cytotoxicity assays, and annexin/propidium-iodide flow cytometry assays of apoptosis/necrosis were performed. Results: The C17.2-Luc NPCs and primary NPCs had well-established characteristics of neural stem cells. Intact NPCs were decreased in numbers after 12 or 24 hours of in vitro ischemia followed by 2 or 12 hours of reperfusion. The cell death rate could be reduced (20%~60%) by a preceding hypoxia of 30 min or 1 hour duration. The flowcytometry study suggested that the decreased rates of aopototic or apopto-necrotic deaths were responsible for the improved cell viability. Conclusions: In summary, this study demonstrated that the hypoxic preconditioning could protect NSCs against subsequent lethal ischemia.

The Life of Professor C. Miller Fisher: A Giant of Stroke Medicine

김동억 대한뇌졸중학회 2020 Journal of stroke Vol.22 No.3

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