Advances in EMAT Technology and Applications

López, Borja; Ali, S.

doi:10.32548/2020.me-04141

Cited by 3 publications

(1 citation statement)

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“…Electro-Magnetic Acoustic Transducer (EMAT) technology, laser ultrasound and air-coupled ultrasound are currently three widely used noncontact ultrasonic detection methods. EMAT technology is suitable for thickness measurement and defect characterization of various metal pipes or plates, and can be applied under high-temperature conditions [ 8 ]. The low energy conversion efficiency, the short distance between the coil and the tested structure limit the application and development of related technologies, and the material to be tested is required to have good conductivity or ferromagnetism [ 9 ].…”

Section: Introductionmentioning

confidence: 99%

Noncontact Damage Topography Reconstruction by Wavenumber Domain Analysis Based on Air-Coupled Ultrasound and Full-Field Laser Vibrometer

Hui

Liang

Rui

et al. 2021

Sensors

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Noncontact ultrasonic detection technology is an effective method to detect damage in time. This paper proposes a noncontact damage detection system based on air-coupled ultrasound and full-field laser vibrometer, which realizes the excitation of relatively single-mode guided waves and the wavefield automatic detection. The system performance is verified through experiments, and the experimental wavenumber is consistent with the theoretical dispersion characteristics of the Lamb wave in the A0 mode. Based on this system, the topography reconstruction algorithms, including the Wavenumber Filtering Algorithm and Spatial Wavenumber Algorithm, were tested and compared with the aluminum alloy plate and the carbon fiber reinforced polymer plate. The results show that, based on the air-coupled ultrasound and full-field laser vibrometer detection system, the Spatial Wavenumber Algorithm has better imaging error and contrast, and the damage edge detection is smoother.

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Section: Introductionmentioning

confidence: 99%

Noncontact Damage Topography Reconstruction by Wavenumber Domain Analysis Based on Air-Coupled Ultrasound and Full-Field Laser Vibrometer

Hui

Liang

Rui

et al. 2021

Sensors

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Research Progress of Suzuki-Miyaura Cross-Coupling Reaction Mechanism

Zhang¹,

Yang²,

Guo³

et al. 2021

Chinese Journal of Organic Chemistry

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During the past several decades, Suzuki-Miyaura cross-coupling reaction has emerged and flourished as one of the most remarkable and practical methods to construct C-C bond. The substrates, organoboronic compounds, are usually more stable, less toxic and easier to obtain compared with other metal or metalloid alternatives. Suzuki-Miyaura cross-coupling reaction possesses extraordinary merits of demonstrated efficiency, broad functional group compatibility and mild reaction conditions. It has been the premier method to construct C-C bond for organic synthetic chemists and has been widely applied in the industrial syntheses. The rapid development of Suzuki-Miyaura cross-coupling reaction is accompanied with the progress of mechanism studies. It is well accepted that the catalytic cycle of Suzuki-Miyaura cross-coupling reaction contains three main steps: oxidative addition of organic halides to Pd catalysts, transmetalation between oxidative addition intermediates and organoboronic compounds, and reductive elimination from transmetalation intermediates to form C-C bond along with regenerating Pd catalysts. However, these three main steps can be influenced by diverse reaction conditions, and different reaction pathways may occur within each single step. Furthermore, beyond the oxidative addition and transmetalation intermediates, other transient but crucial intermediates may exist. To figure out these issues and discover more insights into Suzuki-Miyaura cross-coupling reaction, numerous researchers have designed and conducted systematic investigations. Herein, the recent progress of mechanism studies is summarized and discussed. The steps of oxidative addition, transmetalation and reductive elimination are discussed in detail. Moreover, a brief introduction of transition-metal-free and base-free Suzuki-Miyaura cross-coupling reactions which show more possibilities of the reaction mechanism is given. Besides summary of precedent research works, our opinions about future development of the mechanism studies are also given. Although breakthroughs have been made in the mechanism studies, further investigations are needed to bring comprehensive knowledge of this reaction and help us further optimize the reaction conditions.

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Recent Advances in Hydrochlorination of Alkenes

Wang¹,

Yang²

2021

Chinese Journal of Organic Chemistry

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Organochlorides have been widely used in medicine, pesticides, materials and other fields. In addition, organochlorides are also important synthetic building blocks. They have participated in a variety of reactions, such as free radical reactions, substitution reactions and cross-coupling reactions. The hydrochlorination of olefins is one of the most direct and efficient methods for the synthesis of organochlorides, and remakable breakthroughs have been made in the past thirty years. The research progress of olefin hydrochlorination in the past three decades is introduced. According to whether metal catalysis is involved, it is mainly classified into two categories: metal-free alkene hydrochlorination and metal-catalyzed alkene hydrochlorination. Different type of hydrochlorination reactions and related mechanisms are summarized. In addition, the future development direction of alkene hydrochlorination is prospected.

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Advances in EMAT Technology and Applications

Cited by 3 publications

References 0 publications

Noncontact Damage Topography Reconstruction by Wavenumber Domain Analysis Based on Air-Coupled Ultrasound and Full-Field Laser Vibrometer

Noncontact Damage Topography Reconstruction by Wavenumber Domain Analysis Based on Air-Coupled Ultrasound and Full-Field Laser Vibrometer

Research Progress of Suzuki-Miyaura Cross-Coupling Reaction Mechanism

Recent Advances in Hydrochlorination of Alkenes

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