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지수창함수를 사용한 임팩트햄머 실험에서 주파수응답함수의 왜곡과 개선책
안세진,정의봉 한국소음진동공학회 2003 한국소음진동공학회 논문집 Vol.13 No.5
Exponential window function Is widely used In impact hammer testing to reduce leakage error as well as to get a good S/N ratio. The larger its decaying rate is, the more effectively the leakage errors are reduced. But if the decay rate of the exponential window is too large, the FRF is distorted. And the modal parameters of the system can not be exactly identified by modal analysis technique. Therefore, it is a difficult problem to determine proper decay rate in impact hammer testing. In this paper, amount of the FRF distortion caused by exponential window is theoretically uncovered. A new circle fitting method is also proposed so that the modal parameters are directly extracted from impulse response spectrum distorted by the exponential-windowed impulse response data. The results by the conventional and proposed circle fitting method are compared through a numerical example.
안세진,이탁기 한국해양공학회 2019 韓國海洋工學會誌 Vol.33 No.6
Recently, researchers in Korea and abroad actively have conducted research activities using the ARAON, a Korean icebreaking research vessel. The ARAON regularly conduct research activities in the Arctic and Antarctic waters every year. The icebreaking mode, which can be either continuous breaking or ramming, is determined by the conditions of the ice and the ice-covered waters. When the icebreaker encounters thick sea ice or an ice ridge, ramming is used. At that time, the speed of the ship generally is slower than that of continuous icebreaking. In this study, the ice load signal at the time of repetitive ramming during ARAON’s 2012 Antarctic research voyage was analyzed. The time history of the ice load signal and the change in the speed of the ship used in ramming were compared with these values during continuous icebreaking.
안세진,SHANMUGAMMANIVANNAN,서예지,김규원 대한화학회 2019 Bulletin of the Korean Chemical Society Vol.40 No.6
Electrochemically deposited standing platinum (Pt) nanoplates were fabricated on gold (Au) substrate assisted by the amine functionalized silane and L-glutamic acid (LG) as nucleating and structure directing agents, respectively. Various win over factors responsible for the electrodeposition of the Pt nanoplates was methodologically analyzed. The treatment time with the thiol functionalized silane (M) and the role of LG were found to be decisive for the demonstration of Pt nanoplates display at the Au substrate. Plausible growth mechanism was proposed for the vertical growth and random orientation of the Pt nanoplates. Constructed Pt nanoplates displayed substrate were applied as a sensor platform toward the nitrite ion detection; improved performance was noted than that of the controlled experiments. Furthermore, sensor platform had exhibited recent selectivity toward the nitrite ions from the mixture of possible interferences.
안세진,정의봉,황대선 한국소음진동공학회 2002 한국소음진동공학회 논문집 Vol.12 No.9
The rigid body properties of a structure may be estimated easily if the mass-line of the structure could be taken exactly. However, the exact mass-line nay be hard to be obtained exactly in experiments. The mass line value can be read from the mass line in frequency response function. However, the mass lines in the frequency response function sometimes show the fluctuation with frequency, and it cannot be read correctly. In this paper, the wavelet transform is applied to obtain the good mass line value. The mass line calculated by using wavelet transform has unique value and showed in the range of fluctuated values of frequency response function. The rigid body properties obtained by wavelet transform also showed better results than those by fourier transform.