국산 침엽수 5수종의 페놀계 고농도 붕산염 난연제 주입에 따른 연소특성 평가

구영모 ( Yeong-mo Koo ),최병훈 ( Byeong-hoon Choi ),강석구 ( Seog-goo Kang ) 한국목재공학회 2022 한국목재공학회 학술발표논문집 Vol.2022 No.2

This study compared the combustion characteristics of phenolic high-solidity poly-borate fire-retardant for five domestic species of softwood. The five domestic softwoods are Larix kaempferi Carrie (A), Pinus densiflora (B), Chamaecyparis obtuse (C), Abies holophylla (D), and Cryptomeria japonica (E). The prepared specimens were pressure-impregnated with a fire retardant for 1hr under the conditions of 13 bar and 70℃, and then the weight reduction rate according to the injection rate (WPG) for each species and the external radiant heat source (50 kW/㎡) was evaluated. The specific gravities of the five species were highest in the order of A > B> C > D > E. The injection rate (WPG), determined according to the porosity of wood and the difference between the early and late wood, was found to be inversely proportional to the specific gravity. In the 50 kW/㎡ radiant heat source, weight reduction by treatment with phenolic high-solidity poly-borate fire-retardant was the order of E > B > C > D > A. It is expected that there would be a delay effect on the spread of fire when injected wood was applied as a building material. Through this study, it is decided that it will be possible to contribute to increasing the utilization of domestic softwood and improving the fire safety through the development and commercialization of injection wood flame retardants and chemical treatment methods.

논문 : 정보처리 및 복합기술 ; CIFER(R)를 이용한 무인 헬리콥터의 동특성 분석 (2) -주파수 응답 해석-

배영환 ( Yeong Hwan Bae ),구영모 ( Young Mo Koo ) 한국농업기계학회 2011 바이오시스템공학 Vol.36 No.6

The aerial application using an unmanned helicopter has been already utilized and an attitude controller would be developed to enhance the operational convenience and safety of the operator. For a preliminary study of designing flight controller, a state space model for an RC helicopter would be identified. Frequency sweep flight tests were performed and time history data were acquired in the previous study. In this study, frequency response of the flight test data of a small unmanned helicopter was analyzed by using the CIFER software. The time history flight data consisted of three replications each for collective pitch, aileron, elevator and rudder sweep inputs. A total of 36 frequency responses were obtained for the four control stick inputs and nine outputs including linear velocities and accelerations and angular velocities in 3-axis. The results showed coherence values higher than 0.6 for every primary control inputs and corresponding on-axis outputs for the frequency range from 0.07 to 4 Hz. Also the analysis of conditioned frequency response showed its effectiveness in evaluating cross coupling effects. Based on the results, the dynamic characteristics of the model helicopter can further be analyzed in terms of transfer functions and the undamped natural frequency and damping ratio of each critical mode.

CIFER(R)를 이용한 무인 헬리콥터의 동특성 분석 (3) -전달함수 해석-

배영환 ( Yeong Hwan Bae ),구영모 ( Young Mo Koo ) 한국농업기계학회 2012 바이오시스템공학 Vol.37 No.3

Purpose: Aerial application of chemicals with an agricultural helicopter allows for precise and timely spraying and reduces working labor and pollution. An attitude controller for an agricultural helicopter would be helpful to aerial application operator. The objectives of this paper are to determine the transfer function models and to estimate the handling qualities of a bare-airframe model helicopter. Methods: Transfer functions of a model unmanned helicopter were estimated by using NAVFIT and DERIVID modules of the CIFER? program to the time history data of frequency sweep flight tests. Control inputs of the transfer functions were elevator, aileron, rudder and collective pitch stick positions and the outputs were resulting on-axis movements of the fuselage. Results: Minimum realization of the transfer functions for pitch rate output to elevator control input and roll rate output to aileron control input produced second order transfer functions with undamped natural frequencies around 3.0 Hz and damping ratios of 0.139 and 0.530, respectively. The equivalent time delays of the transfer functions ranged from 0.16 to 0.44 second. Sensitivity analysis of the proposed parameters allowed derivation of minimal realization of the transfer functions. Conclusions: Handling quality of the model helicopter was addressed based on the eigenvalues of the transfer functions, corresponding undamped natural frequencies with damping ratios. The equivalent time delays of the lateral-directional motion ranged from 0.16 to 0.44 second, longer than the 0.1 to 0.15 second requirement for well-controlled typical manned aerial vehicles.

CIFER ^® 를 이용한 무인 헬리콥터의 동특성 분석 (III) - 전달함수 해석 -

배영환,구영모,Bae, Yeong-Hwan,Koo, Young-Mo 한국농업기계학회 2012 바이오시스템공학 Vol.37 No.3

Purpose: Aerial application of chemicals with an agricultural helicopter allows for precise and timely spraying and reduces working labor and pollution. An attitude controller for an agricultural helicopter would be helpful to aerial application operator. The objectives of this paper are to determine the transfer function models and to estimate the handling qualities of a bare-airframe model helicopter. Methods: Transfer functions of a model unmanned helicopter were estimated by using NAVFIT and DERIVID modules of the $CIFER^{(R)}$ program to the time history data of frequency sweep flight tests. Control inputs of the transfer functions were elevator, aileron, rudder and collective pitch stick positions and the outputs were resulting on-axis movements of the fuselage. Results: Minimum realization of the transfer functions for pitch rate output to elevator control input and roll rate output to aileron control input produced second order transfer functions with undamped natural frequencies around 3.0 Hz and damping ratios of 0.139 and 0.530, respectively. The equivalent time delays of the transfer functions ranged from 0.16 to 0.44 second. Sensitivity analysis of the proposed parameters allowed derivation of minimal realization of the transfer functions. Conclusions: Handling quality of the model helicopter was addressed based on the eigenvalues of the transfer functions, corresponding undamped natural frequencies with damping ratios. The equivalent time delays of the lateral-directional motion ranged from 0.16 to 0.44 second, longer than the 0.1 to 0.15 second requirement for well-controlled typical manned aerial vehicles.

Fusarium avenaceum에 의한 복숭아 신규 과실 썩음병 발생 보고

허아영(A Yeong Heo),구영모(Young Mo Koo),최영준(Young-Joon Choi),김상희(Sang Hee Kim),정규영(Gyu Young Chung),최형우(Hyong Woo Choi) 한국식물병리학회 2020 식물병연구 Vol.26 No.1

In July 2019, typical rot symptom was observed on peach fruits harvested from the fields at Andong, Korea. As the disease progressed, white and purple colored mycelial mat developed on the surface of the infected fruits. A causal pathogen was isolated from the infected fruit and cultured on potato dextrose agar media for identification. Fungal colonies on potato dextrose agar produced 3 pigments, including purple, yellow, and white colors. The isolate incited fruit rot symptoms on artificially inoculated peach fruits, from which the same fungus was isolated, fulfilling Koch’s postulates. Based on the morphological characteristics and sequence analysis of rDNA internal transcribed spacer, translation elongation factor 1-alpha, and β-tubulin, the causal agent of the disease was identified as Fusarium avenaceum. This study is the first report of fruit rot of peach fruits caused by Fusarium avenaceum in Korea.

논문 : 정보처리 및 복합기술 ; CIFER(R)를 이용한 무인 헬리콥터의 동특성 분석 (1) -조종기 제어 입력 데이터 획득을 위한 비행시험-

박희진 ( Hee Jin Park ),구영모 ( Young Mo Koo ),배영환 ( Yeong Hwan Bae ),오민석 ( Min Suk Oh ),양철오 ( Chul Oh Yang ),송명현 ( Myung Hyun Song ) 한국농업기계학회 2011 바이오시스템공학 Vol.36 No.6

Aerial spraying technology using a small unmanned helicopter is an efficient and practical tool to achieve stable agricultural production to improve the working condition. An attitude controller for the agricultural helicopter would be helpful to aerial application operator. In order to construct the flight controller, a state space model of the helicopter should be identified using a dynamic analysis program, such as CIFER(R). To obtain the state space a model of the helicopter, frequency-sweep flight tests were performed and time history data were acquired using a custom-built stick position transmitter. Four elements of stick commands were accessed for the collective pitch (heave), aileron (roll), elevator (pitch), rudder (yaw) maneuvers. The test results showed that rudder stick position signal was highly linear with rudder input channel signal of the receiver; however, collective pitch stick position signal was exponentially manipulated for the convenience of control stick handling. The acquired stick position and flight dynamic data during sweep tests would be analyzed in the followed study.

페놀계 고농도 붕산염 난연제처리 파티클보드의 물리·기계적 성능

최병훈 ( Byeong-hoon Choi ),구영모 ( Yeong-mo Koo ),강석구 ( Seog-goo Kang ) 한국목재공학회 2022 한국목재공학회 학술발표논문집 Vol.2022 No.2

This study was conducted to analyze the effect of phenolic high solidity borate flame retardant on the physical and mechanical properties of particle boards. The flame retardant was applied as 3, 7, 11 and 15% of the total dry weight of the particles, respectively. The resin content was 12%, and the target density was set at 0.7g/㎤. In order to verify the physical and mechanical properties of the particle board, an experiment was conducted according to KS F 3104. In addition, in order to evaluate the performance of the flame-retardant, a test using a 45° meckel burner was performed in accordance with KS F 2819. Results show that the flame- retardant performance increased as the amount of treatment increased, and all of the treated materials passed the flame-retardant performance standards of the fire department. Physical and mechanical properties increased with treatment rate up to 7%, and decreased at higher treatment rates. Therefore, the most appropriate treatment was determined to be 7%. The properties of the particle board manufacturednin the laboratory have been verified, and it is decided that it is necessary to study the product applied to the production process.

버섯 폐배지의 연료화 및 품질개선을 위한 반탄화 최적화 연구

이창구 ( Chang-goo Lee ),최병훈 ( Byeong-hoon Choi ),구영모 ( Yeong-mo Koo ),강석구 ( Seog-goo Kang ) 한국목재공학회 2022 한국목재공학회 학술발표논문집 Vol.2022 No.2

This study was conducted as part of the purpose of realizing the fuelization and quality improvement using spent mushroom substrate through a torrefaction pretreatment. Conditions of torrefaction pretreatment were performed at temperatures of 250, 350, and 450°C and reaction times of 600, 1,200, and 1,800s, respectively. In order to confirm the fuel characteristics were conducted to proximate analysis and higher heating value. As the experimental materials, to determine the tendency of spent mushroom substrate according to the cultivation period of Letinula edodes, the products discarded after harvesting 2, 4, 6 and 8 cycles were used. As a result, higher heating value and content of fixed carbon has been increased and contents of moisture content and ash has been decreased the more torrefaction pretreatment for temperature and time increased. Furthermore, the results of calculating the energy yield through the higher heating value and the mass yield, it found that most suitable for molded charcoal of the manufacturing a conditions of 1,200-1,800s of 350°C in this study.

3축 가속도 센서를 이용한 이동 물체의 자세각 측정

양철오(Chul-Oh Yang),이대성(Dae-Sung Lee),오민석(Min-Suk Oh),박희진(Hee-Jin Park),구영모(Young-Mo Koo),배영환(Yeong-Hwan Bae),송명현(Myung-Hyun Song) 대한전기학회 2010 대한전기학회 학술대회 논문집 Vol.2010 No.7

3축 가속도 센서를 이용해 이동하는 물체의 자세각을 측정할 때 물체의 이동으로 가속도가 발생하므로 이로 인한 오차가 발생한다. 본 연구에서는 이동하는 물체의 가속도에 의한 측정 오차를 줄일 수 있는 물체의 자세각 측정 방법을 제안하였다. 직선 운동하는 리니어 스테이지에 가속도 센서를 고정시켜 실험함으로써, 종래의 방법과 제안한 방법에 의한 측정 결과를 비교하였다.