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RISS 인기검색어
- 검색키워드
- 저자 : Yuanbo Xu (검색결과 5 건)
- 무료
- 기관 내 무료
- 유료
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Yuanbo Xu,Zongyan Cai,Xiaoyan Cai,Kai Ding 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.6
Previous research has shown that minimum entropy deconvolution (MED) is an effective technique for detecting impulse-like signals, such as the bearing fault and gear fault signals. However, some problems still exist in this technique. With the aim of overcoming these limitations, in this paper, an enhanced MED called multipoint optimal minimum entropy deconvolution adjusted (MOMEDA) is proposed. MOMEDA can succeed in detecting multiple impulses. Unfortunately, according to some simulations and real tests in this work, the results of applying this technique to the fault signals directly were grudgingly acceptable but not very satisfactory, especially under a harsh working condition. This means that MOMEDA is a little sensitive to intensive background noise and vibration interference. To overcome this drawback, a novel mode decomposition method, named time-varying filtering for empirical mode decomposition (TVFEMD), is applied to adaptively eliminate background noise and vibration interference prior to using MOMEDA. According to this proposed method, the weak bearing fault features can be identified clearly. The proposed approach is utilized in bearing fault detection of a spur gearbox and the results show its superiority and effectiveness.
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Xu, Jun,Dong, Fengshou,Liu, Xingang,Li, Jing,Li, Yuanbo,Shan, Weili,Zheng, Yongquan Korean Chemical Society 2011 Bulletin of the Korean Chemical Society Vol.32 No.12
A method based on ethyl acetate extraction and gas chromatography with tandem mass spectrometry was developed for determining tetraconazole residues in fruits and vegetables. A 10 g homogenized sample was mixed with 10 mL ethyl acetate, shaken vigorously for 3 min, stored at $-20^{\circ}C$ for 15 min, and then vortexed vigorously for 1 min; 1 g NaCl and 4 g anhydrous $MgSO_4$ were added. The clean-up was carried out by applying dispersive solid-phase with 150 mg $MgSO_4$and 50 mg primary secondary amine. Three precursor product ion transitions for tetraconazole were measured and evaluated to provide the maximum degree of confidence. Average recoveries in fruits and vegetables at three levels (0.005, 0.05 and 0.5 mg/kg) ranged from 85.53% to 110.66% with relative standard deviations ($RSD_r$) from 1.3% to 17.5%. The LODs ranged from 0.002 to 0.004 ${\mu}g$/kg, and LOQs ranged from 0.006 to 0.012 ${\mu}g$/kg. This method was also applied to determine tetraconazole residue in cucumber dissipation experiment under field conditions. The half-lives of tetraconazole in cucumber were in the range of 2.1-3.1 days.
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Kun Wu,Yuanbo Xu,Na Yang,Liang Zhao 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.3
Fault signals measured from a damaged rolling bearing usually exhibit amplitude modulation (AM)-frequency modulation (FM) properties. For this kind of signal, the demodulation technique is an effective and common method. In the demodulation techniques, a variety of energy operator (EO) tools have been available due to high computational efficiency and self-adaptability to transient signals. Hence, an alternative energy measure is proposed in this work. The new demodulation technique is achieved by combining a multiresolution higherorder symmetric difference sequence with the envelope-derivative operator (EDO). The multiresolution higher-order symmetric envelope-derivative operator (MHOS-EDO) can extract the weak bearing fault characteristics in a harsh environment without any pre-filtering. Especially in the presence of vibration interferences, its unique energy transformation can eliminate the influence of vibration interferences, so that the vibration interferences will no longer appear in the energy spectrum. Through simulation and practical experiments, the superiority of MHOS-EDO in dealing with noise and interfering components is demonstrated. Meanwhile, the comparison results reveal that the MHOS-EDO outperforms some previous EO and some other bearing fault identification methods.
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Yongquan Zheng,Jun Xu,Fengshou Dong,Xingang Liu,Jing Li,Yuanbo Li,,Weili Shan 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.12
A method based on ethyl acetate extraction and gas chromatography with tandem mass spectrometry was developed for determining tetraconazole residues in fruits and vegetables. A 10 g homogenized sample was mixed with 10 mL ethyl acetate, shaken vigorously for 3 min, stored at −20 oC for 15 min, and then vortexed vigorously for 1 min; 1 g NaCl and 4 g anhydrous MgSO4 were added. The clean-up was carried out by applying dispersive solid-phase with 150 mg MgSO4 and 50 mg primary secondary amine. Three precursor product ion transitions for tetraconazole were measured and evaluated to provide the maximum degree of confidence. Average recoveries in fruits and vegetables at three levels (0.005, 0.05 and 0.5 mg/kg) ranged from 85.53% to 110.66% with relative standard deviations (RSDr) from 1.3% to 17.5%. The LODs ranged from 0.002 to 0.004 μg/kg, and LOQs ranged from 0.006 to 0.012 μg/kg. This method was also applied to determine tetraconazole residue in cucumber dissipation experiment under field conditions. The half-lives of tetraconazole in cucumber were in the range of 2.1-3.1 days.
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Yan Wang,Lichen Gu,Yuanbo Xu 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.3
The bearing fault signal is a kind of weak signal, so it is easy to be submerged by background noise. As such, signature extraction is facing a great challenge; hence, an effective signature extraction method plays an essential role in bearing fault extraction. In this paper, a new method for bearing fault detection based on an alternative analytic energy operator and sparse Bayesian step-filtering (SBSF) was applied. The SBSF technique can remove much background noise from the raw signal and enhance the characteristics related to the bearing fault. Besides, it has also a high calculation efficiency. Afterward, an improved analytic energy operator, the symmetric high-order analytic energy operator (SHO-AEO), which is an enhanced demodulation technique that outperforms the conventional demodulation technique, was applied to detect bearing fault signatures from filtered signals. The proposed energy measure is formed using the original signal, its Hilbert transform, and its high-order derivatives. Unlike traditional energy operators, it includes the information of the real and imaginary parts of the analytic signal. As a demodulation technique, it is also tailored to extract both the amplitude and frequency modulations from the filtered signal. Furthermore, compared with the previous energy operators, it provides better anti-noise capability. Hence, the proposed fault detection method of combining the SHO-AEO and SBSF not only has high computational efficiency but also provides much better noise handling potential. Through simulated and real tests, this proposed method is demonstrated to be robust against various noise levels and to detect the bearing fault signature.
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