구조물-가진기 상호작용에 의한 공진주파수 변동에 대한 해석

한상보,Han, Sang-Bo 대한기계학회 1996 大韓機械學會論文集A Vol.20 No.7

The purpose of this paper is to investigate the influence of the exciter attached for the measurement of natural frequencies when extracting the frequency response functions of the test structure in experimental modal analysis. The procedure is first to model the attached exciter as an additional degree of freedom system and next to verify the suggested model by experimentally extracting the natural frequencies of the test structure with various values of exciter mass, stinger stiffness and attachment position of the exciter on the test structure. It is concluded that as additional degree of freedom system which includes the natural frequency of the exciter itself and axial stiffness of stinger should be considered to quantatively define the coupling effects of structure-exciter interaction on the measured natural frequencies. It is not the mass of the exciter itself but the coupling effect of the additional degree of freedom mass-spring system consisting of exciter body and armature coil that characterizes the natural frequency deviation. Therefore, when the natural frequency of this additional mass-spring system is outside of the test frequency range, the coupling effect of structure-exciter interaction can be minimized.

사이클로헥산을 이용한 다이아몬드 박막제작 연구

한상보(Sang-Bo Han),박상현(Sang-Hyun Park),박재윤(Jae-Youn Park),이승지(Seoung-Ji Lee),곽태영(Tae-Young Kwak) 대한전기학회 2009 대한전기학회 학술대회 논문집 Vol.2009 No.7

본 논문은 마이크로웨이브 플라즈마 프로세스에 의하여 사이클로헥산을 이용한 다이아몬드 박막 제작에 관한 산소유량 변화 및 파라메타 변화에 따른 분광분석 결과에 대하여 논하였다. 인가전력을 증가시킴에 따라서 수소원자의 H<SUB>α</SUB> 및 H<SUB>β</SUB>의 발광강도는 증가되는 반면에 CH(B-X) 발광강도는 일정하였으며, 헥산 유량을 증가시킴에 따라 CH(B-X) 라디칼의 발광강도가 증가되고, 산소유량을 증가시킴에 따라CH(B-X) 라디칼이 산소원자와의 결합에 의해 밀도가 감소하여 발광강도가 감소되었다. 그리고, 산소가 공급되지 않은 경우에는 비정질 또는 DLC 성분이 많이 함유된 결정성이 거의 없는 다이아몬드 박막이 성장 되었으며, 산소유량을 증가시킴에 따라서 결정 표면에 잔존하는 미결합 탄소성분들이 제거되면서 결정성이 향상됨을 알 수 있었다. 본 연구를 통하여 유기용매인 사이클로헥산을 이용하여 다이아몬드 박막이 성장됨을 확인할 수 있었다.

ADC 컨버터 내장형 고효율 BLDC 모터 개발 및 특성평가 연구

한상보(Sang-Bo Han) 한국전기전자학회 2019 전기전자학회논문지 Vol.23 No.4

본 논문은 ADC 컨버터 내장 단상 직입구동 20W BLDC 모터 개발 및 출력 특성에 대한 연구결과를 논하였다. PWM 인버터 스위칭을 통해 회전자를 구동시키고, 모터의 역기전력을 홀센서 위상각 신호보다 전기적으로 30° 앞서도록 위치시켜 최적의 스위칭 타임을 확보하도록 제작하였다. 특성평가의 주요한 결과로서 인버터 효율 최대 92[%], 시스템 효율 53.34[%]를 보였으며, 모터 효율은 57.85[%] 보였다. This paper discussed the research results on the development and output characteristics of single-phase direct drive 20W BLDC motor with ADC converter. It is designed to drive the rotor through PWM inverter switching and position the back electromotive force of the motor electrically 30° ahead of the hall sensor phase angle signal to ensure optimum switching time. As a major result of the characteristics evaluation, the maximum inverter efficiency was 92[%], the system efficiency was 53.34[%,] and the motor efficiency was 57.85[%].

질소-메탄올 혼합기체 중 대기압 방전에 따른 분광분석 연구

한상보(Sang-Bo Han),김종현(Jong-Hyun Kim),박재윤(Jae-Youn Park),정만길(Man-Gil Jung),구본국(Bon-Kook Koo) 대한전기학회 2013 대한전기학회 학술대회 논문집 Vol.2013 No.7

대기압 플라즈마 프로세스에 있어서 시간에 따른 화학종의 밀도변화 연구

한상보(Sang-Bo Han),박성수(Sung-Su Park),김종현(Jong-Hyun Kim),박재윤(Jae-Youn Park) 한국조명·전기설비학회 2013 조명·전기설비학회논문지 Vol.27 No.7

This study is to discuss simulation results with 51 principal chemical reactions in non-thermal plasma space under atmospheric pressure, and the ambient gas was mainly composed of oxygen and nitrogen molecules. The initial density of O and OH radicals under the ambient temperature of 300K is largely generated in comparison with other higher temperature, and the density of O radical decreased from 20㎲ according to increase the temperature. The initial density of OH radical seemed to decrease steeply at the initial stage. By increasing the initial density of H₂O molecules, O radical’s effect was few and the density of OH radical was largely generated about 2 times. In addition, ozone density was increased as increasing the density of O radical, but it was decreased as increasing the density of H₂O. In case of the temperature more than 300K, NO₂ tend to be removed, but NO was increased than the initial density.

전류 및 자속센서를 이용한 유도전동기 예방진단 알고리즘 개발에 관한 연구

한상보(Sang-Bo Han) 한국전기전자학회 2019 전기전자학회논문지 Vol.23 No.4

본 논문은 전류신호와 자속신호를 이용한 유도전동기 예방진단시스템을 개발하기 위한 머신러닝 알고리즘의 개발 및 적용 결과에 대하여 논하였다. 유도전동기의 결함 종류를 판별하기 위한 최적 특징추출단계를 통하여 총 29개의 특징을 도출하였다. 특히, 전류신호의 제7차 고조파 중심으로부터 사이드밴드까지의 주파수의 차이가 부하율 증가에 따라서 증가되는 경향을 이용하여 임의의 부하율 상태를 반영할 수 있는 알고리즘을 도출하였으며, KPCA 특징 축소 기법, k-NN 판단 알고리즘에 의한 분류 정확도를 조사한 결과, 약 84.6%의 분류 정확도를 보였다. This paper discussed the results of the development and application of the machine learning algorithm to the induction motor for the preventive diagnostic system using current and magnetic flux signals. The optimal 29 features were extracted for identifying faulted types of induction motor. In particular, any load rate was derived using the tendency of the difference value from the center of the 7th harmonic frequency to the sideband of the current signal, and the corresponding classification accuracy showed about 84.6% by the KPCA feature reduction technique and the k-NN determination algorithm.

Microwave Plasma Process에 의한 N-Hexane으로부터 다이아몬드 박막제작 및 특성

한상보(Sang-Bo Han),권태진(Tae-Jin Kwon),박상현(Sang-Hyun Park),박재윤(Jae-Youn Park),이승지(Seung-Ji Lee) 한국조명·전기설비학회 2011 조명·전기설비학회논문지 Vol.25 No.4

In this paper, the best conditions for the deposition of the high quality diamond thin-film from N-hexane as a carbon source in the microwave plasma process was carried out. Major parameters are the deposition time, flow rates of oxygen and hexane. The deposition time for the steady state thin-film was required more than 4[h], and the suitable flow rates of hexane and oxygen for the high-quality thin-film are 0.4[sccm] and 0.1~0.2[sccm], respectively. In addition, amorphous carbons such as DLC and graphite were grown by increasing the flow rate of hexane, and it decreased by increasing the flow rate of oxygen. Specifically, the growth rate is about 1.5[㎛h-1] under no addition of oxygen and it decreased about 60[%] as ca. 1.0[㎛h-1] with oxygen.

마이크로웨이브 플라즈마 CVD 프로세스에 의해 증착된 다이아몬드 박막의 원자 결합구조에 관한 연구

한상보(Sang-Bo Han) 대한전기학회 2019 전기학회논문지 Vol.68 No.12

In this paper, the effects of carbon source and oxygen flow rates on the growth of high-quality polycrystalline diamond thin-film by MPECVD process and the interatomic binding characteristics by boron doping were investigated. As the N-hexane flow rate increases, the peak near 285.7eV on the high binding energy due to the carbon-carbon double bond (π bond) increases, and the crystallinity was reduced such as the decrease of the peak of single bond (σ defect). By supplying oxygen, the sp3 peak, which is a diamond carbon-carbon bond, was evident and the crystallinity was increased. In addition, the valence band electron distribution of the diamond film with high crystallinity was peaked at about 8.7eV, and the bandgap was found to be between 5.2 and 5.5eV.

Blumlein 펄스파워 전원개발 및 방전특성 평가

한상보(Sang-Bo Han),박상현(Sang-Hyun Park) 한국조명·전기설비학회 2010 조명·전기설비학회논문지 Vol.24 No.10

This paper discussed the theoretical simulation results for developing the blumlein pulsed power source and showed the circuit configuration and the discharge characteristics of the realistic manufactured pulsed power system. In the simulation, the output voltage characteristics at a load resistor showed the general impulse shape when the impedance of a single coaxial cable is matched with the that of a load resistor. In addition, it is confirmed that output values of the pulsed power can be easily controlled by the duplication of coaxial cables and the pulsed waveform showed the general impulse characteristics. Specifically, the inception discharge voltage in the gap distance of 5[㎜] between needle and plane electrodes is about 20[㎸] and which is lower than about 29[㎸] in 9[㎜] due to the difference of the reaching time of the inception voltage. Therefore, this paper showed that the output voltage of the blumlein pulsed power source can be easily controlled.

레이져 유기형광법을 이용한 펄스 배리어 방전 공간에서의 NO분자에 대한 시․공간적 밀도변화 측정

한상보(Sang-Bo Han) 한국조명·전기설비학회 2010 조명·전기설비학회논문지 Vol.24 No.5

본 논문은 대기압 펄스 배리어 방전을 이용하여 NO 가스를 무해한 물질로 환원시키기 위하여 방전공간에서의 NO 분자의 생성 및 제거과정에 대하여 레이져 유기형광법을 이용하여 시?공간적인 밀도변화를 측정 및 분석하였다. 사용된 펄스 배리어 방전리액터는 진전속도가 2.7×10?[㎧]인 1차 스트리머가 음극표면에 도착한 이후에 2차 스트리머가 양극 부근에 발생되었다. 그리고, 펄스 레이져에 의하여 NO 분자만을 효율적으로 상위준위로 여기시키기 위하여 Nd:Yag 및 염료 레이져를 복합하여 226[㎚]의 자외광을 방전공간으로 도입하였으며, NO 분자만을 A²Σ? ← X²Ⅱ(0.0)으로 여기시키고, 여기된 분자들이 낮은 준위 A²Σ? → X²Ⅱ(0,2),(0,3)로 복귀됨에 따라 방출되는 주요한 형광신호를 측정하였다. NO 분자의 시?공간적 변화 측정결과로부터 NO 가스를 효율적으로 제거하기 위해서는 산소농도를 가능한 2 [%]이하로 낮추고, 2차 스트리머 진전에 의해서 충분하게 방전공간에서 NO 환원반응을 유발할 수 있도록 제어하는 것이 필요하다고 판단된다. This paper tried to find out NO generation and removal mechanisms in the space of the atmospheric pulsed barrier discharge using laser induced fluorescence method, which is a very effective approach to the measurement of spatio-temporal density of specific molecules. The propagation velocity of the primary streamer reaches about 2.7×10?[㎧] and the secondary streamer is produced in the vicinity of positive electrode after the primary streamer finished. In this work, pulse Nd:Yag and Dye lasers are used for generating the specific wavelength of 226[㎚], which is possible to excite NO molecules into A²Σ? ← X²Ⅱ(0.0) and fluorescence signals as the transition of A²Σ? → X²Ⅱ(0,2),(0,3) is measured. For the effective removal of NO molecules in the plasma discharge process, the lower oxygen contents are needed and the influence of secondary streamer for the reduction mechanism of NO molecules is important.