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김덕현(Dukhyun Kim),강동기(Donggi Kang),이형진(Hyoungjin Lee),조준현(Joonhyun Cho),정해영(Haeyoung Jung) 한국추진공학회 2016 한국추진공학회 학술대회논문집 Vol.2016 No.12
초소형 유도무기에 대한 개발 필요성이 부각되고 있는 상황에서 본 연구를 통해 초소형 열가소성 추진기관을 적용한 비행체를 개발함으로써 추후 실제 초소형 유도무기 추진기관 개발 가능성을 확인하고자 하였다. 추진기관 성능 분석을 통하여 초소형 추진기관의 요구 성능을 도출하였으며 요구조건을 만족하기 위한 저 연소속도 추진제 조성을 개발 및 공력 형상 설계를 수행하였다. 지상연소시험를 통하여 추진제 성능 및 추진기관의 성능을 확인하였고, 실제 비행 시험을 통해 성능 분석 결과와 일치하는 것을 확인함으로써 초소형 추진기관 개발 가능성을 확인하였다. In a situation that a needs of subminiature guided missile development is being magnified, an unguided missile appled thermoplastic propellant was developed to confirm a possibility of development on subminiature guided missile rocket motor. A requirement of rocket motor was derived by conducting performance analysis. A propellant composition having low burning rate was developed and an aerodynamic configuration design was conducted to satisfy the requirement. The performance of propellant and rocket motor was confirmed through ground firing test. The possibility of development subminiature rocket motor was confirmed by ascertaining the fact that the simulation results was in close agreement with the flight test results.
김미나(Mina Kim),이승길(Seungkil Lee),이용식(Yongsik Lee),조삼래(Samrae Cho),김덕현(Dukhyun Kim) 한국환경보건학회 2018 한국환경보건학회지 Vol.44 No.2
Objectives: This study was carried out to determine LD 50 of benzo[a]pyrene to decide the possibility to designate them as toxic substance on the Act on the Registration and Evaluation, etc. of Chemical Substances, and to suggest that they should be managed in what level on the Chemical Control Act. Methods: Based on the result of a preliminary study, 300 mg/kg was set as the middle dose. A highest dose of 2,000 mg/kg and a lowest dose of 50 mg/kg were selected based on the OECD TG 423. Benzo[a]pyrene was orally administered once to female and male SD rats at dose levels of 50, 300, 2,000 mg/kg (body weight). All animals were monitored daily for clinical signs and mortality over 14 days. Also testicular spermatid count, motility and etc. were examined as well. Results: Under the condition of this experiment, LD 50 of benzo[a]pyrene was assumed to be >2,000 mg/kg. In the lesion according to autopsy, there were no specific symptoms in the control and experimental groups. At 2,000 mg/kg, a decrease in the sperm motility was observed. Benzo[a]pyrene should be designated to be toxic substance as the material assumed to be reproduction-toxicity on the Act on the Registration and Evaluation, etc. of Chemicals. Therefore we should abide by legal procedures determined by Chemicals Control Act in treating it. Conclusion: Considering the significant result that sperm motility in the experimental group was inferior to that in the reference group, we suggest that benzo[a]pyrene be designated as a toxic substance.
김미나 ( Mina Kim ),이승길 ( Seungkil Lee ),조삼래 ( Samrae Cho ),김덕현 ( Dukhyun Kim ) 한국산업보건학회 (구 한국산업위생학회) 2018 한국산업보건학회지 Vol.28 No.1
Objectives: This study was performed to observe the toxicological changes caused by a single exposure to benzo[a]pyrene. Methods: Based on the results of a preliminary study, 300 mg/kg was set as the middle dose. A highest dose of 2,000 mg/kg and a lowest dose of 50 mg/kg were selected based on GHS guidelines. Benzo[a]pyrene was orally administered once to female and male SD rats at dose levels of 50, 300, and 2,000 mg/kg (body weight). All animals were monitored daily for clinical signs and mortality over 14 days. Hematological and biochemical values were examined as well. Results: There were neither dead animals nor significant changes in body weights during the experimental period. In addition, no differences were found between the control and treated groups in clinical sign, hematology, serum biochemical, and histopathological analysis. Conclusion: Compared with the control group, we could not detect any toxic alteration in all treated groups. These studies indicate that the acute toxicity of benzo[a]pyrene is relatively low.
정기연(Kiyeon Jeong),김덕현(Dukhyun Kim),이충희(Choonghee Lee),이형진(Hyoungjin Lee) 한국추진공학회 2016 한국추진공학회 학술대회논문집 Vol.2016 No.12
고체추진기관의 연속적인 추력조절에 적합한 핀틀 노즐에 대한 수치해석적 연구를 수행하였다. 핀틀 노즐은 핀틀과 노즐의 직경비에 따라 관통형과 비관통형으로 나뉘며, 본 연구에서는 핀틀 직경이 노즐 직경보다 큰 비관통형을 선택하였다. 노즐은 초음속 출구조건을 가지며 직선형인 conical과 곡선형인 bell 노즐을 비교하였다. 핀틀의 형상은 면적 변화부분이 1차 기울기 값을 가지는 형상을 선택하여 노즐 목의 변화가 선형적으로 변하도록 설계하였다. 수치해석은 STAR-CCM+ 10.06을 이용하여 수행하였으며 노즐과 핀틀의 형상 변화에 대한 노즐 내 유동변화, 추력의 변화를 비교하였다. Numerical simulations have been performed to investigate the proper nozzle shape for thrust control of pintle nozzle. The type of pintle nozzle was divided to through-type and non through-type from the ratio of pintle and nozzle diameter. the designed nozzle has supersonic exit condition, diverging section of nozzle has straight(conical nozzle) and curve(bell nozzle) shape respectively. the pintle shape was designed at negative first order gradient to linearize change of nozzle throat. STAR-CCM+ 10.06 was used to analysis the flow characteristics in the nozzle and variation of thrust.
두파장 스캐닝 라이다 시스템을 이용한 고해상도 미세먼지 질량 농도 산출
노영민 ( Youngmin Noh ),김덕현 ( Dukhyun Kim ),최성철 ( Sungchul Choi ),최창기 ( Changgi Choi ),김태경 ( Taegyeong Kim ),김가형 ( Gahyeong Kim ),신동호 ( Dongho Shin ) 대한원격탐사학회 2020 大韓遠隔探査學會誌 Vol.36 No.6
532와 1064 nm 두 파장 관측 채널을 구비하고 수평으로 360° 스캐닝 관측이 가능한 스캐닝 라이다 시스템을 개발하였다. 또한, 두 파장에서의 후방산란계수를 이용하여 미세먼지를 PM<sub>2.5-10</sub>(조대)와 PM<sub>2.5</sub>(미세)입자로 구분하는 분석도 개발하여 스캐닝 라이다 시스템의 데이터 분석에 적용하였다. 개발된 스캐닝 라이다를 이용한 울산 온산공단에서 관측에서 각각 22 - 110 μg/㎥과 7 - 78 μg/㎥의 분포를 보이는 PM<sub>10</sub>과 PM<sub>2.5</sub>의 질량 농도를 성공적으로 산출하였다. 분석된 결과는 라이다 관측 영역 주변에서 지상에서 측정된 질량농도와 유사한 값을 보였으며, 공장 등에서 배출되는 지점에서는 이 각각 80-110 μg/㎥과 60-78 μg/㎥의 고농도가 측정되는 사례를 확인하였다. A scanning lidar system has been developed. The system has two wavelength observation channels of 532 and 1064 nm and is capable of 360-degree horizontal scanning observation. In addition, an analysis method that can classify the measured particle as an indicator of coarse-mode particle (PM<sub>2.5-10</sub>) and an indicator of fine-mode particles (PM<sub>2.5</sub>) and calculate the mass concentration of each has been developed by using the backscatter coefficient at two wavelengths. It was applied to the data calculated by observation. The mass concentrations of PM<sub>10</sub> and PM<sub>2.5</sub>, which showed a distribution of 22-110 μg/㎥ and 7-78 μg/㎥, respectively, were successfully calculated in the Ulsan Onsan Industrial Complex using the developed scanning lidar system. The analyzed results showed similar values to the mass concentrations measured on the ground around the lidar observation area, and it was confirmed that high concentrations of 80-110 μg/㎥ and 60-78 μg/㎥ were measured at points discharged from factories, respectively.
손민(Min Son),김덕현(Dukhyun Kim),구자예(Jaye Koo) 한국추진공학회 2010 한국추진공학회 학술대회논문집 Vol.2010 No.5
터보펌프식 액체 로켓 엔진에 대해 AMESim을 이용하여 1-D 시스템을 구성하고 시동 과도 특성을 해석하였다. 액체산소와 RP-1을 추진제로 사용하는 개방형 사이클에 대해 해석을 수행하였으며, 초기 시동시 가스발생기의 연료 밸브 개방 및 가스발생기 점화 타이밍과 시동 안정성의 관계에 관한 결과를 얻었다. 이러한 연구를 바탕으로 터보펌프식 액체 로켓 엔진 시스템의 최적 설계를 위해 시동시 특성 및 시동 절차를 고려해야 함을 확인 하였다. One dimensional transient analysis was studied for turbopump-fed liquid propellant rocket engine(LRE) system in starting using AMESim. The effects of timing of gas generator fuel valve opening and gas generator ignition to start-up stability were researched for open cycle type system using LOX/RP-1 to propellants. Result show that the parameters and sequence on start-up should be considered to design optimized turbopump-fed LRE system.