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Preventing formation of intermetallic compounds in ultrasonic-assisted Sn soldering of Mg/Al alloys through pre-plating a Ni coating layer on the Mg substrate

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Journal of Magnesium and Alloys 2024年第2期12卷 726-741页

作者： Yingzong Liu Yuanxing Li Hui Chen Zongtao Zhu Key Laboratory of Advanced Technologies of Materials Ministry of EducationSchool of Materials Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031PR China

Magnesium and aluminum alloys are widely used in various industries because of their excellent properties,and their reliable connection may increase application of *** compounds(IMCs)affect the joint performance of Mg/*** this study,AZ31 Mg alloy with/without a nickel(Ni)coating layer and 6061 Al alloy were joined by ultrasonic-assisted soldering with Sn-3.0Ag-0.5Cu(SAC)*** effects of the Ni coating layer on the microstructure and mechanical properties of Mg/Al joints were systematically *** Ni coating layer had a significant effect on formation of the Mg_(2)Sn IMC and the mechanical properties of Mg/Al *** blocky Mg_(2)Sn IMC formed in the Mg/SAC/Al joints without a Ni coating *** content of the Mg_(2)Sn IMC increased with increasing soldering temperature,but the joint strength *** joint without a Ni coating layer fractured at the blocky Mg_(2)Sn IMC in the solder,and the maximum shear strength was 32.2 *** pre-plating Ni on the Mg substrate,formation of the blocky Mg_(2)Sn IMC was inhibited in the soldering temperature range 240–280℃and the joint strength ***,when the soldering temperature increased to 310℃,the blocky Mg_(2)Sn IMC precipitated again in the *** electron microscopy showed that some nano-sized Mg_(2)Sn IMC and the(Cu,Ni)_(6)Sn_(5)phase formed in the Mg(Ni)/SAC/Al joint soldered at 280℃,indicating that the Ni coating layer could no longer prevent diffusion of Mg into the solder when the soldering temperature was higher than 280℃.The maximum shear strength of the Mg(Ni)/SAC/Al joint was 58.2 MPa for a soldering temperature of 280℃,which was 80.7%higher than that of the Mg/SAC/Al joint,and the joint was broken at the Mg(Ni)/SAC ***-plating Ni is a feasible way to inhibit formation of IMCs when joining dissimilar metals.

关键词： Ultrasonic-assisted soldering Mg_(2)Sn Ni coating layer Shear strength

Photoinduced generation of alkyl and phthalimide nitrogen radicals from N-hydroxyphthalimide esters for the synthesis of benzophenone-type bioisosteres

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Science China Chemistry 2024年第10期67卷 3389-3396页

作者： Fei Li Jianyang Dong Huijuan Liao Jiayi Dang Xuechen Zhou Yuying Wang Chenya Wang Qin Jiang Gang Li Dong Xue Key Laboratory of Applied Surface and Colloid Chemistry Ministry of Education and School of Chemistry and Chemical EngineeringShaanxi Normal UniversityXi’an 710119China

N-Hydroxyphthalimide(NHPI)esters have emerged as powerful sources of alkyl radicals generated by single-electron transfer,but homolysis of NHPI ester to produce an alkyl radical and a phthalimide nitrogen radical is still in its *** this study,we developed a light-induced method for generation of alkyl and phthalimide nitrogen radicals from NHPI esters and subsequent reactions of the radicals with[1.1.1]propellane and aryl aldehydes for rapid generation of bicycle[1.1.1]pentane *** method does not require metals or photosensitizers,features a broad substrate scope(90 examples)and excellent functional group tolerance,and can be used for the functionalization of structurally complex natural products and *** investigations indicate that the reaction involves photoinduced homolytic cleavage of the Cs_(2)CO_(3)-NHPI ester complex to produce alkyl and phthalimide nitrogen radicals and subsequent hydrogen atom transfer between the phthalimide nitrogen radical and the aldehyde to generate an acyl radical.

关键词： phthalimide nitrogen radicals aryl aldehydes hydrogen atom transfer bicycle[1.1.1]pentane ketones bioisosteres

Spin-orbit torque effect in silicon-based sputtered Mn_(3)Sn film

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Chinese Physics B 2024年第10期33卷 394-399页

作者： Sha Lu Dequan Meng Adnan Khan Ziao Wang Shiwei Chen Shiheng Liang school of Physics Hubei UniversityWuhan 430062China Key Laboratory for Intelligent Sensing System and Security of Ministry of education Wuhan 430062China

Noncollinear antiferromagnet Mn_(3)Sn has shown remarkable efficiency in charge-spin conversion,a novel magnetic spin Hall effect,and a stable topological antiferromagnetic state,which has resulted in great interest from researchers in the field of spin-orbit *** research has primarily focused on the spin-orbit torque effect of epitaxially grown noncollinear antiferromagnet Mn_(3)Sn ***,this method is not suitable for large-scale industrial *** this study,amorphous Mn_(3)Sn films and Mn_(3)Sn/Py heterostructures were prepared using magnetron sputtering on silicon *** spin-torque ferromagnetic resonance measurement demonstrated that only the conventional spin-orbit torque effect generated by in-plane polarized spin currents existed in the Mn_(3)Sn/Py heterostructure,with a spin-orbit torque efficiency of ***,we prepared the perpendicular magnetized Mn_(3)Sn/CoTb heterostructure based on amorphous Mn_(3)Sn film,where the spin-orbit torque driven perpendicular magnetization switching was achieved with a lower critical switching current density(3.9×10^(7)A/cm^(2))compared to Ta/CoTb *** research reveals the spin-orbit torque effect of amorphous Mn_(3)Sn films and establishes a foundation for further advancement in the practical application of Mn_(3)Sn materials in spintronic devices.

关键词： spintronics noncollinear antiferromagnetism spin-orbit torque

Upgrading waste NO_(x) into amino acids via electrocatalysis on Co nanoparticles encapsulated in hollow carbon nanofibers

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Science China Chemistry 2024年第6期67卷 1946-1952页

作者： Jiahui Xian Kaixing Cai Peisen Liao Shihan Wang Guangqin Li Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of education LIFMIGCMESchool of ChemistrySun Yat-Sen UniversityGuangzhou510275China

Electrocatalytic conversion of waste nitrogen oxide(NO_(x))into value-added nitrogenous chemicals,especially amino acid,is an emerging strategy to alleviate NO_(x)***,this process suffers from the coexistence of multiple competitive reactions leading to complex product distribution and low efficiency,and thus the rational design and modulation of efficient catalysts remains a formidable ***,well-designed Co nanoparticles encapsulated in hollow carbon nanofiber(CoHCNF)were constructed to promote the amino acid electrosynthesis via dealing waste NO_(x)coupling with biomass-derived keto *** to the rapid reactant diffusion,electron transport and efficient contact with abundant accessible Co catalytic sites stemmed from the unique hollow nanotubular structure,Co-HCNF manifested impressive glycine synthesis performance in one-pot adopting NO as the nitrogen source with Faradaic efficiency(FE)of 41.7%and a corresponding yield rate of 222.3μmol h^(-1)as well as 120 h robust ***,it also demonstrates an excellent performance with the FE of 42.8%for NO_(3)~-solution as the nitrogen ***,this strategy displays a broad universality for the synthesis of other amino *** work not only highlights the importance of hollow-structuring electrocatalyst towards upgrading wasted NO_(x)species into amino acids,but also promotes the further development of electrosynthetic systems for high-valued N-containing organic chemicals.

关键词： electrocatalysis NO_(x)reduction amino acid porous materials hollow structure

Plasma-assisted ammonia synthesis under mild conditions for hydrogen and electricity storage:Mechanisms,pathways,and application prospects

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Frontiers in Energy 2024年第4期18卷 418-435页

作者： Feng GONG Yuhang JING Rui XIAO Key Laboratory of Energy Thermal Conversion and Process Measurement and Control of the Ministry of education School of Energy and EnvironmentSoutheast UniversityNanjing 210096China

Ammonia,with its high hydrogen storage density of 17.7 wt.%(mass fraction),cleanliness,efficiency,and renewability,presents itself as a promising zero-carbon ***,the traditional Haber−Bosch(H−B)process for ammonia synthesis necessitates high temperature and pressure,resulting in over 420 million tons of carbon dioxide emissions annually,and relies on fossil fuel *** contrast,dielectric barrier discharge(DBD)plasma-assisted ammonia synthesis operates at low temperatures and atmospheric pressures,utilizing nitrogen and hydrogen radicals excited by energetic electrons,offering a potential alternative to the H−B *** method can be effectively coupled with renewable energy sources(such as solar and wind)for environmentally friendly,distributed,and efficient ammonia *** review delves into a comprehensive analysis of the low-temperature DBD plasma-assisted ammonia synthesis technology at atmospheric pressure,covering the reaction pathway,mechanism,and catalyst system involved in plasma nitrogen *** from current research,it evaluates the economic feasibility of the DBD plasmaassisted ammonia synthesis technology,analyzes existing dilemmas and challenges,and provides insights and recommendations for the future of nonthermal plasma ammonia processes.

关键词： plasma catalysis nitrogen fixation ammonia synthesis hydrogen storage catalyst carbon neutralization

Conductive and stable polyphenylene/CNT composite membrane for electrically enhanced membrane fouling mitigation

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Frontiers of Environmental Science & Engineering 2024年第1期18卷 35-47页

作者： Huijuan Xie Haiguang Zhang Xu Wang Gaoliang Wei Shuo Chen Xie Quan Key Laboratory of Industrial Ecology and Environmental Engineering(Ministry of education) School of Environmental Science and TechnologyDalian University of TechnologyDalian 116024China

Nanocarbon-based conductive membranes, especially carbon nanotube (CNT)-based membranes, have tremendous potential for wastewater treatment and water purification because of their excellent water permeability and selectivity, as well as their electrochemically enhanced performance (e.g., improved antifouling ability). However, it remains challenging to prepare CNT membranes with high structural stability and high electrical conductivity. In this study, a highly electroconductive and structurally stable polyphenylene/CNT (PP/CNT) composite membrane was prepared by electropolymerizing biphenyl on a CNT hollow fiber membrane. The PP/CNT membrane showed 3.4 and 5.0 times higher electrical conductivity than pure CNT and poly(vinyl alcohol)/CNT (PVA/CNT) membranes, respectively. The structural stability of the membrane was superior to that of the pure CNT membrane and comparable to that of the PVA/CNT membrane. The membrane fouling was significantly alleviated under an electrical assistance of −2.0 V, with a flux loss of only 11.7% after 5 h filtration of humic acid, which is significantly lower than those of PP/CNT membranes without electro-assistance (56.8%) and commercial polyvinylidene fluoride (PVDF) membranes (64.1%). Additionally, the rejection of negatively charged pollutants (humic acid and sodium alginate) was improved by the enhanced electrostatic repulsion. After four consecutive filtration-cleaning cycle tests, the flux recovery rate after backwashing reached 97.2%, which was much higher than those of electricity-free PP/CNT membranes (67.0%) and commercial PVDF membranes (61.1%). This study offers insights into the preparation of stable conductive membranes for membrane fouling control in potential water treatment applications.

关键词： Polyphenylene CNTs Membrane Electro-assistance Membrane fouling mitigation

Experimental studies of H_(2)/Ar plasma in a cylindrical inductive discharge with an expansion region

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Chinese Physics B 2024年第10期33卷 321-330页

作者： Shi-Bo Li Si-Yu Xing Fei Gao You-Nian Wang Key Laboratory of Materials Modification by Laser Ionand Electron Beams(Ministry of Education)School of PhysicsDalian University of TechnologyDalian 116024China

The electrical parameters of H_(2)/Ar plasma in a cylindrical inductive discharge with an expansion region are investigated by a Langmuir probe,where Ar fractions range from 0%to 100%.The influence of gas composition and pressure on electron density,the effective electron temperature and the electron energy probability functions(EEPFs)at different spatial positions are *** driver region,with the introduction of a small amount of Ar at 0.3 Pa,there is a rapid increase in electron density accompanied by a decrease in the effective electron ***,the shape of the EEPF transitions from a three-temperature distribution to a bi-Maxwellian distribution due to an increase in electron-electron ***,this phenomenon resulting from the changes in gas composition vanishes at 5 Pa due to the prior depletion of energetic electrons caused by the increase in pressure during hydrogen *** EEPFs for the total energy in expansion region is coincident to these in the driver region at 0.3 Pa,as do the patterns of electron density variation between these two regions for differing Ar *** 5 Pa,as the discharge transitions from H_(2)to Ar,the EEPFs evolved from a bi-Maxwellian distribution with pronounced low energy electrons to a Maxwellian distribution in expansion *** evolve may be attributed to a reduction in molecular vibrational excitation reactions of electrons during transport and the transition from localized electron dynamics in hydrogen discharge to non-localized electron dynamics in argon *** order to validate the experimental results,we use the COMSOL simulation software to calculate electrical parameters under the same *** evolution and spatial distribution of the electrical parameters of the simulation results agree well with the trend of the experimental results.

关键词： inductively coupled plasma transmission and distribution energy distribution functions

Surfactant-metal-organic framework complexes and their derivatives:advances in electrocatalysis

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Science China Chemistry 2024年第10期67卷 3209-3222页

作者： Yining Liu Mengying Wang Zuozhong Liang Haoquan Zheng Key Laboratory of Applied Surface and Colloid Chemistry Ministry of EducationSchool of Chemistry and Chemical EngineeringShaanxi Normal UniversityXi’an 710119China

Metal-organic frameworks(MOFs)and their derivatives received more and more attention due to the diverse morphologies,rich porous structures,and tunable metal active sites,which have been widely used in energy-related electrocatalytic ***,a class of compounds with hydrophilic and hydrophobic portions in the molecular structure,are able to modulate the properties of liquid and solid *** play a crucial role in controlling the shape and size of MOFs,which helps optimize electrocatalytic performance,especially in improving the exposure and accessibility of catalytic active *** this review,we first outline the types and applications of ***,we describe the interface modulation and reaction mechanism of different surfactants during the forming of MOFs and their ***,we discuss the current applications of surfactant-modified MOFs and their derivatives in *** review provides a better understanding of surfactantassistant structure regulation and electrocatalytic activity study of MOFs and their derivatives.

关键词： metal-organic frameworks surfactants interface modulation electrocatalysis

Discharge mode and particle transport in radio frequency capacitively coupled Ar/O_(2)plasma discharges

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Chinese Physics B 2024年第9期33卷 451-460页

作者： Zhuo-Yao Gao Wan Dong Chong-Biao Tian Xing-Zhao Jiang Zhong-Ling Dai Yuan-Hong Song Key Laboratory of Materials Modification by Laser Ionand Electron Beams(Ministry of Education)School of PhysicsDalian University of TechnologyDalian 116024China

Simulations are conducted on capacitively coupled Ar/O_(2)mixed gas discharges employing a one-dimensional fluid coupled with an electron Monte Carlo(MC)*** research explores the impact of different O_(2)ratio and pressures on the discharge characteristics of Ar/O_(2)*** a fixed Ar/O_(2)gas ratio,with the increasing pressure,higher ion densities,as well as a slight increase in electron density in the bulk region can be *** discharge remains dominated by the drift-ambipolar(DA)mode,and the flux of O(3P)at the electrode increases with the increasing pressure due to higher background gas density,while the fluxes of O(1D)and Ardecrease due to the pronounced loss *** the increasing proportion of O_(2),a change in the dominant discharge mode from a mode to DA mode can be detected,and the O_(2)-associated charged particle densities are significantly ***,Ar+density shows a trend of increasing and then decreasing,while for neutral fluxes at the electrode,Arflux decreases,and O(3P)flux increases with the reduced Ar gas proportion,while trends in O(1D)flux show slight *** evolution of the densities of the charged particle and the neutral fluxes under different discharge parameters are discussed in detail using the ionization characteristics as well as the transport ***,more comprehensive understanding of Ar/O_(2)discharge characteristics in this work will provide a valuable reference for the industry.

关键词： Ar/O_(2) mixed gas discharges electron dynamics transport of charged and neutral particles