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RISS 인기검색어
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- 저자 : YUXING PENG (검색결과 3 건)
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PENG AN,FANG ZUO,XINHUA LI,YUANPENG WU,JUNHUA ZHANG,ZHAOHUI ZHENG,XIAOBIN DING,YUXING PENG 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2013 NANO Vol.8 No.6
A biomimetic and facile approach for integrating Fe3O4 and Au with polydopamine (PDA) was proposed to construct gold-coated Fe3O4 nanoparticles (Fe3O4@Au–PDA) with a core–shell structure by coupling in situ reduction with a seed-mediated method in aqueous solution at room temperature. The morphology, structure and composition of the core–shell structured Fe3O4@Au–PDA nanoparticles were characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD) and X-ray photoelectron spectrometry (XPS). The formation process of Au shell was assessed using a UV-Vis spectrophotometer. More importantly, according to investigating changes in PDA molecules by Fourier transform infrared spectroscopy (FTIR) and in preparation process of the zeta-potential data of nanoparticles, the mechanism of core–shell structure formation was proposed. Firstly, PDA-coated Fe3O4 are obtained using dopamine (DA) self-polymerization to form thin and surface-adherent PDA films onto the surface of a Fe3O4 "core". Then, Au seeds are attached on the surface of PDA-coated Fe3O4 via electrostatic interaction in order to serve as nucleation centers catalyzing the reduction of Au3+ to Au0 by the catechol groups in PDA. Accompanied by the deposition of Au, PDA films transfer from the surface of Fe3O4 to that of Au as stabilizing agent. In order to confirm the reasonableness of this mechanism, two verification experiments were conducted. The presence of PDA on the surface of Fe3O4@Au–PDA nanoparticles was confirmed by the finding that glycine or ethylenediamine could be grafted onto Fe3O4@Au–PDA nanoparticles through Schiff base reaction. In addition, Fe3O4@Au–DA nanoparticles, in which DA was substituted for PDA, were prepared using the same method as that for Fe3O4@Au–PDA nanoparticles and characterized by UV-Vis, TEM and FTIR. The results validated that DA possesses multiple functions of attaching Au seeds as well as acting as both reductant and stabilizing agent, the same functions as those of PDA.
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Jun Gu,Yuxing Peng,Hao Lu,Bobo Cao,Guoan Chen 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.10
Aiming at the complex fault signal components and difficulty in identifying the fault features of a hoist spindle device, this study proposes a method based on a filtering algorithm, Hilbert-Huang transform (HHT), energy entropy, and support vector machines (SVM). The filtering method is applied to the vibration signal under different fault conditions. Then, the Hilbert-Huang transform is applied to the noise-reduced signal. The empirical mode decomposition (EMD) method decomposes the noise-reduced vibration signal into a set of intrinsic mode functions (IMF). Then, the Hilbert transform (HT) calculates the envelope spectrum of the first few IMFs. Afterward, it evaluates and extracts the fault characteristic frequencies. Finally, the identification of different fault defect types is determined by combining the intrinsic modal energy entropy and SVM. The experimental results show that the method can accurately identify the faults in the rotor bearing system and is an effective fault signal processing method.
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Highly selective magnetic polymer particles via molecular imprinting
Xiaobing Wang,Guihua Qiu,Yi Ge,Wei Zheng,Lingmei Kong,Yajuan Xue,Bin Ren,YUXING PENG 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.11
Magnetic hydrophilic molecularly imprinted polymer (MIP) particles were successfully synthesized via an inverse suspension polymerization in silicone oil, by employing methacryloxypropyltrimethoxysilane(MPS)-modified Fe3O4 nanoparticles as magnetic particles, 2,4-dichlorophenoxyacetic acid (2,4-D) as template, hydroxyethyl methacrylate (HEMA) as hydrophilic monomer, and acetonitrile as high polar porogen. The synthesized magnetic hydrophilic MIP particles could be separated rapidly under an external magnetic field. About 94% transmittance of the particlewater suspension could be reached within 20 min by magnetic separation, whereas about 84% transmittance was achieved after at least 180min by sedimentation. The adsorption capacity of the particles was also studied in pure aqueous environments. These hydrophilic MIP particles had a higher selectivity for templates. Hydrophilic MIP particles took on a higher imprinting factor than hydrophobic MIP particles and 2,4-D were able to rebind hydrophilic MIP particles more easily than 4-Chorophenoxyacetic acid.
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