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Effect of trigger system on experimental dispersion characteristics of active surface wave testing

Earthquake Engineering and Engineering Vibration 2024年第2期23卷 311-318页

作者： Lin Shibin Jeramy c.Ashlock Zhu Liming Qin Zexiang Li bo Zhu Xingji Zhai changhai State Key Laboratory of Precision Blasting Jianghan UniversityWuhan 430056China Hubei Key Laboratory of Blasting Engineering Jianghan UniversityWuhan 430056China Department of civil Construction&Environmental EngineeringIowa State UniversityAmesIA 50010USA Wuhan Airport Road Development co. Ltd.Wuhan 430065China School of civil and Environmental Engineering Harbin Institute of TechnologyShenzhen 518055China Key Lab of Structures Dynamic Behavior and control of the Ministry of Education Harbin Institute of TechnologyHarbin 150090China Key Lab of Smart Prevention and Mitigation of civil Engineering Disaster of the Ministry of Industry and Information Technology Harbin Institute of TechnologyHarbin 150090China

A trigger system is typically employed in active seismic testing to trigger and synchronize multichannel surface wave data *** effect of the trigger system on the dispersion image of surface waves is empirically known to be negligible,however,theoretical explanation regarding the effect of the trigger system is *** study systematically examines the theory for surface wave dispersion analysis and proves that the effect of the trigger system on a dispersion image is negligible via a solid theoretical ***,based on the new theoretical explanation,an alternative method that uses only the relative phase difference between sensors to extract dispersion characteristics with better conceptual clarity is *** active surface wave testing cases are considered to validate the theory and *** results indicate that(1)an accurate trigger system is not necessary for surface wave data acquisition,and(2)it is unnecessary to assume that the impact point is the generation point of the surface waves for the experimental dispersion analysis.

关键词： site investigation surface waves data acquisition dispersion

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Simple preparation of c(cS)/g-c_(3)N_(4)/co carbon aerogel and its catalytic performance for ammonium perchlorate

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Defence Technology（防务技术） 2024年第3期33卷 186-196页

作者： Yujie Yan bo Jin Rufang Peng State Key Laboratory of Environment-friendly Energy Materials School of Materials Science and EngineeringSouthwest University of Science and TechnologyMianyang621010China

Biomass chitosan(cS)was used as a template,graphitic phase carbon nitride(g-c_(3)N_(4))with high nitrogen content and certain catalytic activity was used as a dopant,and nano-transition metal cobalt(co)was used as a catalytic center *** carbon aerogel(c(cS)/g-c_(3)N_(4)/co)with a three-dimensional network-like structure was prepared by assembling the three materials through experimental operations such as freeze-drying and high-temperature *** was demonstrated by scanning and transmission characterization that the cS in the carbon aerogel could provide more active sites for the cobalt nanoparticles,and the doping of graphite-phase carbon nitride as a template dispersed the cobalt nanoparticles and changed the conductivity of the *** investigate the catalytic effect of carbon aerogel on ammonium perchlorate(AP),it was investigated by differential thermal analyzer and TG thermal *** carbon aerogel was very effective in catalyzing AP,and the 10 wt% content of the catalyst reduced the AP pyrolysis peak from 703.9 to 595.5 *** to further investigate the synergistic effect of the three materials,further carbon aerogels such as c(cS)/co,g-c_(3)N_(4)/co were prepared and applied to catalyze AP,and the same ratio reduced the AP pyrolysis peak by 98.1℃ and 97.7℃.This result indicates a synergistic effect of the assembly of the three materials.

关键词： g-c_(3)N_(4) chitosan co Ammonium perchlorate Pyrolysis kinetics

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Access to High-Molecular-Weight Polyethylenes through High Temperature Ethylene Polymerization catalysed by Ethylene-Bridged ansa-(3-R-cyclopentadienyl)(Fluorenyl) Zirconocene complexes

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chinese Journal of Polymer Science 2024年第1期42卷 42-51,I0007页

作者： bo Li Haiyan Ma Jiling Huang Shanghai Key Laboratory of Functional Materials chemistry and Laboratory of Organometallic chemistry School of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai 200237China

A series of c1-symmetric ethylene-bridged ansa-(3-R-cyclopentadienyl)(fluorenyl) metallocene complexes(Zr: 1-5;Hf: 6) have been synthesized, characterized and investigated as catalyst precursors for the high temperature ethylene polymerization. Using methylaluminoxane(MAO) as the cocatalyst, zirconium complexes 1-5 bearing a bulky substituent on the 3-position of the cyclopendienyl ring showed high catalytic activities up to 1.48×10^(7) g PE·mol_(Zr)^(-1)·h^(-1) toward the polymerization of ethylene and afforded polyethylenes with high molecular weights(1.49×10^(5)-6.31×10^(5) g/mol), meanwhile exhibting great thermal stability at high temperatures up to 120 ℃ together with a long catalytic life time up to 2 h. By adopting low Al/Zr ratios, such as 125, polyethylenes with ultra high molecular weights up to 2.86×106 g/mol were obtained. It is worthy of noting that zirconium complexes 1-4 bearing a substituent with an aryl pendant showed temperature-dependent activities, which increased rapidly with the increase of polymerization temperature, thus weak interaction of the pendent aryl group with the cationic active center is proposed to account for the very low activities displayed at low temperatures. In contrast to zirconocene complexes 1-5, hafnocene complex 6 only displayed very low catalytic activities toward the polymerization of ethylene and afforded polyethylenes with molecular weights ten times smaller than those obtained by zirconocene complexes 1-5. Zirconocene complexes 1-5 were also able to catalyse the polymerization of propylene at high temperatures, but only afforded waxes with low molecular weights.

关键词： ansa-Metallocene Ethylene Propylene Polymerization High temperature

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Deflagration and detonation induced by shock wave focusing at different Mach numbers

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chinese Journal of Aeronautics 2024年第2期37卷 249-258页

作者： Zezhong YANG Jun cHENG bo ZHANG School of Aeronautics and Astronautics Shanghai Jiao Tong UniversityShanghai 200240China

Shock wave focusing is an effective way to create a hot spot or a high-pressure and hightemperature region at a certain place,showing its unique usage in detonation initiation,which is beneficial for the development of detonation-based *** flame propagation behavior after the autoignition induced by shock wave focusing is crucial to the formation and self-sustaining of the detonation *** this study,wedge reflectors with two different angles(60°and 90°)and a planar reflector are employed,and the Mach number of incident shock waves ranging from 2.0 to 2.8 is utilized to trigger different flame propagation *** pressure transducers and the high-speed schlieren imaging system are both employed to investigate the shock-shock collision and ignition *** results reveal a total of four flame propagation modes:deflagration,DDT(Deflagration-to-Detonation Transition),unsteady detonation,and direct *** detonation wave formed in the DDT and unsteady detonation mode is only approximately 75%-85%of the chapman-Jouguet(c-J)speed;meanwhile,the directly induced detonation wave speed is close to the c-J *** waves,which are strong evidence for the existence of detonation waves,are discovered in *** usage of wedge reflectors significantly reduces the initial pressure difference ratio needed for direct detonation *** also provide a practical method for differentiating between detonation and deflagration modes,which involves contrasting the speed of the reflected shock wave with the speed of the theoretically nonreactive reflected shock *** findings should serve as a reference for the detonation initiation technique in advanced detonation propulsion engines.

关键词： Deflagration Detonation Hydrogen Ignition Shock wave focusing

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Layer Hall effect induced by hidden Berry curvature in antiferromagnetic insulators

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National Science Review 2024年第2期11卷 15-23页

作者： Rui chen Hai-Peng Sun Mingqiang Gu chun-bo Hua Qihang Liu Hai-Zhou Lu X.c.Xie Shenzhen Institute for Quantum Science and Engineering and Department of Physics Southern University of Science and Technology(SUSTech) International Quantum Academy Institute for Theoretical Physics and Astrophysics University of Würzburg School of Electronic and Information Engineering Hubei University of Science and Technology Guangdong Provincial Key Laboratory of computational Science and Material Design Southern University of Science and Technology Shenzhen Key Laboratory of Quantum Science and Engineering International center for Quantum Materials School of PhysicsPeking University collaborative Innovation center of Quantum Matter cAS center for Excellence in Topological Quantum computation University of Chinese Academy of Sciences

The layer Hall effect describes electrons spontaneously deflected to opposite sides at different layers, which has been experimentally reported in the MnBi2Te4thin films under perpendicular electric fields. Here, we reveal a universal origin of the layer Hall effect in terms of the so-called hidden Berry curvature, as well as material design principles. Hence, it gives rise to zero Berry curvature in momentum space but non-zero layer-locked hidden Berry curvature in real space. We show that, compared to that of a trivial insulator, the layer Hall effect is significantly enhanced in antiferromagnetic topological insulators. Our universal picture provides a paradigm for revealing the hidden physics as a result of the interplay between the global and local symmetries, and can be generalized in various scenarios.

关键词： layerHall effect hidden Berry curvature antiferromagnetic insulator axion insulator, quantum transport

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Recovery of Li, Ni, co and Mn from spent lithium-ion batteries assisted by organic acids: Process optimization and leaching mechanism

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International Journal of Minerals,Metallurgy and Materials 2024年第3期31卷 518-530页

作者： Liuyi Ren bo Liu Shenxu Bao Wei Ding Yimin Zhang Xiaochuan Hou chao Lin bo chen School of Resources and Environmental Engineering Wuhan University of TechnologyWuhan 430070China State Environmental Protection Key Laboratory of Mineral Metallurgical Resources Utilization and Pollution control Wuhan University of Science and TechnologyWuhan 430081China Zhejiang New Era Zhongneng Recycling Technology co. LtdShaoxing 312000China Shenzhen Water Planning&Design Institute co. LtdShenzhen 518000China

The proper recycling of spent lithium-ion batteries(LIBs)can promote the recovery and utilization of valuable resources,while also negative environmental effects resulting from the presence of toxic and hazardous *** this study,a new environmentally friendly hydro-metallurgical process was proposed for leaching lithium(Li),nickel(Ni),cobalt(co),and manganese(Mn)from spent LIBs using sulfuric acid with citric acid as a *** effects of the concentration of sulfuric acid,the leaching temperature,the leaching time,the solid-liquid ratio,and the reducing agent dosage on the leaching behavior of the above elements were *** parameters were optimized using response surface methodology(RSM)to maximize the recovery of metals from spent *** maxim-um recovery efficiencies of Li,Ni,co,and Mn can reach 99.08%,98.76%,98.33%,and 97.63%.under the optimized conditions(the sulfuric acid concentration was 1.16 mol/L,the citric acid dosage was 15wt%,the solid-liquid ratio was 40 g/L,and the temperature was 83℃ for 120 min),*** was found that in the collaborative leaching process of sulfuric acid and citric acid,the citric acid initially provided strong reducing cO_(2)^(-),and the transition metal ions in the high state underwent a reduction reaction to produce transition metal ions in the low ***,citric acid can also act as a proton donor and chelate with lower-priced transition metal ions,thus speeding up the dissolution process.

关键词： spent lithium-ion batteries leaching response surface methodology sulfuric acid citric acid

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Selective N-Methylation of N-Methylaniline with cO_(2) and H_(2) over cu/In_(2)O_(3) catalyst

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chinese Journal of chemistry 2024年第3期42卷 276-282页

作者： Huan Zheng bo Qian Lin He State Key Laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhouGansu730000 China University of chinese Academy of Sciences Beijing100049 China

N-Methylation of amines with cO_(2) and H2 is a potential approach for cO_(2) utilization because N-methylated amines can be used as solvents and organic intermediates. In_(2)O_(3)-supported cu (cu/In_(2)O_(3)) acts as an effective heterogeneous catalyst for N-methylation reaction of N-methylaniline (MA) with cO_(2) and H_(2),showing higher N,N-dimethylaniline (DMA) selectivity than other supported cu catalysts. On one hand,the dispersion of cu can be improved by the defective In_(2)O_(3) support. On the other hand,In_(2)O_(3) support is active in the dissociative adsorption of cO_(2) through c—O bond breaking. In addition,the H_(2) dissociation ability of In_(2)O_(3) can also be enhanced by cu. The combination of cu and In_(2)O_(3) is effective in the activation of cO_(2),the adsorption of intermediate N-methylformanilide (MFA),the hydrogenation of MFA to DMA and the prohibition of c—N bond cleavage side reactions,thereby enhancing the reaction rate of MA conversion and the selectivity to DMA.

关键词： N-Methylation cO_(2) cu/In_(2)O_(3) Supported catalysts Heterogeneous catalysis

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Plasma spray coating on interconnector toward promoted solid oxide fuel cells and solid oxide electrolysis cells

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Frontiers in Energy 2024年第3期18卷 390-398页

作者： Junwen cAO Yun ZHENG Wenqiang ZHANG bo YU Institute of Nuclear and New Energy Technology(INET) Collaborative Innovation Center of Advanced Nuclear Energy TechnologyTsinghua UniversityBeijing 100084China Department of chemical Engineering University of WaterlooWaterlooOntario N2L 3G1Canada Institute of New Energy Materials and Engineering School of Materials Science and EngineeringFuzhou UniversityFuzhou 350108China

Interconnector is a critical component to construct solid oxide cells (SOcs) stack. Oxidation of metallic interconnectors and cr poisoning caused by oxidation are important factors that lead to long-term performance degradation of SOcs. coating on the interconnector surface is an important approach to inhibit the oxidation and cr migration of the interconnector. Herein, (La0.75Sr0.25)0.95MnO3–δ (LSM) and Mn1.5co1.5O4 (McO) are used to fabricate the coatings of interconnector. Two advanced thermal spray technology, atmospheric plasma spraying (APS) and low-pressure plasma spray (LPPS), are adopted for the coating preparation. The electrochemical performance, rising and cooling cycle stability, and cr diffusion inhibition performance of the coatings are tested and evaluated. The result indicates that McO can generate more uniform and denser coatings than LSM. In addition, McO coatings prepared by LPPS shows the best electrochemical performance, rising and cooling cycle stability, and cr diffusion inhibition. The initial area specific resistance (ASR) is 0.0027 Ω·cm2 at 800 °c. After 4 cooling cycle tests, the ASR increases to 0.0032 Ω·cm2 but lower than other samples. Meanwhile, the relative intense of cr at the interface of SUS430 with McO coatings fabricated by LPPS is lower than that of McO fabricated by APS after 4 rising and cooling cycle operations, showing more favorable cr diffusion inhibition performance.

关键词： interconnector coating plasma spray electrochemical performance cr diffusion inhibition solid oxide cells(SOcs)

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Forced boiling of nonazeotropic immiscible mixture in a supercapillary microchannel array for ultra-high heat flux removal with chip junction temperature below 85℃

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Science china(Technological Sciences) 2024年第5期67卷 1364-1380页

作者： SUN bo BAO Yuchen TIAN Tong LI Ji School of Engineering Science University of Chinese Academy of SciencesBeijing100049China Laboratory of Advanced Thermal Management Technologies School of Engineering ScienceUniversity of Chinese Academy of SciencesBeijing100049China

In this study,a structure-optimized two-phase microchannel heat sink with sintered submicron nucleation sites was developed and *** copper-based microchannels had a rectangular cross-section with an equivalent hydraulic diameter of 222μ*** subcooled flow boiling characteristics were comprehensively compared between pure HFE-7100 and a non-azeotropic,immiscible binary mixture of HFE-7100 and water,considering heating areas of 1 and 5 cm^(2).The total heating power input to the test section were 100–1500 and 250–3000 W for a 1 and 5 cm^(2)heat source,respectively,with a flow rate ranging from 50 to150 L/*** to pure HFE-7100,the non-azeotropic immiscible binary mixture of HFE-7100/water in the sintered porous microchannels exhibited a much higher overall heat transfer coefficient and lower power *** maintain the junction temperature of a high power electronic chip below 85℃,the proposed supercapillary microchannel heat sink could effectively dissipate the heat flux of 1275 W/cm^(2)over 1 cm^(2)heat source and 500 W/cm^(2)over 5 cm^(2)heat *** addition,the volume ratio of the binary mixture strongly influence the two-phase flow heat transfer *** optimal volume ratio exist in terms of the thermal resistance–pumping power minimization(HFE-7100:water=2:8 is recommended in this study).The findings of this investigation on the flow boiling properties of non-azeotropic immiscible mixtures help fill a gap in the related field.

关键词： microchannel sintered powder coating submicron nucleation cavities nonazeotropic immiscible ultra-high heat flux

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Heterocatalytic ethylene methoxycarbonylation via a pseudo-hydride pathway over Pt_(1)/MoS_(2)

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Science china chemistry 2024年第8期67卷 2427-2428页

作者： bo-Hang Zhao Bin Zhang Institute of Molecular Plus Department of ChemistrySchool of ScienceTianjin UniversityTianjin 300072China

Ethylene (c2H4) methoxycarbonylation (EMc) with cO and methanol (cH3OH) to methyl propanoate (MP) is industrially important due to its 100% atom efficiency [1].However, the heavy reliance on homogeneous Pd-based catalysts and strong acid media over commercial EMc processes still causes economic and environmental concerns [2]. At present, supported single-atom catalysts (SAcs) can serve as bridges for accessing homogeneous catalysts in traditional heterogeneous catalytic processes.

关键词： processes. catalytic hydride

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