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Enhanced photothermal dehydration of methanol over W_(18)O_(49)/Au/SAPO-34 catalysts with broadened light absorption

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Rare Metals 2024年第3期43卷 1139-1152页

作者： Ya-Qin Tang Meng-Xia Yan Chang-Qian Lu Shao-Yuan Li kui-xian wei Tao Qu Wen-HuiMa Yong-Nian Dai Kong-Zhai Li Da-Jun Luo Xue-Liang Zhang Yi-Ke Liu Faculty of Metallurgical and Energy Engineering Kunming University of Science and TechnologyKunming650093China School of Materials and Energy Engineering Guizhou Institute of TechnologyGuiyang550003China

Methanol-to-olefins(MTO)process is one of the most critical pathways to produce low carbon ***,the reaction is driven by thermal catalysis,which inevitably needs to consume large amounts of fossil *** a new technique to substitute for the fuel burning is urgent for MTO process to improve the industry prospects and ***,we report a novel W_(18)O_(49)/Au/SAPO-34(W/Au/S),a multifunctional photothermal catalyst for the MTO reaction.A high methanol conversion was achieved under xenonum(Xe)lamp irradiation,yielding methyl ether(ME)and ethylene as the main *** optimized W/Au/S catalysts showed ethylene yield as high as 250μmol in 60 min,which was 2.5 times higher than that of Au/*** physiochemical characterization revealed that the SAPO-34 molecular sieves were surrounded by Au and W_(18)O_(49)nanoparticles,which exhibited a strong localized surface plasmon resonance excitation around 540 nm and light absorption beyond 500 *** multifunctional catalysts showed a strong photothermal effect,arising from the broadened light absorption of Au and W_(18)O_(49)nanoparticles,leading to a temperature as high as 250℃on the surface of the *** study showed that the superior ethylene selectivity of W/Au/S catalysts was attributed to the moderating acidic sites of W_(18)O_(49)for methanol dehydration to *** research may provide new insight for designing heterostructures to improve photo-to-chemical conversion performance and is expected to accelerate progress toward the excellent multifunctional photothermal catalysts with broad light absorption for methanol activation and C-C bond formation.

关键词： Methanol conversion Ethylene Photothermal catalysis W_(18)O_(49) BrΦnsted-acid

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Separation and enrichment mechanism of C54–TiSi_(2) from hypoeutectic Ti–65 wt.%Si alloy during directional solidification via alternating electromagnetic fields

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Journal of Iron and Steel Research International 2021年第1期28卷 29-37页

作者： kui‑song Zhu Jing‑fei Hu Wen‑hui Ma kui‑xian wei Yong‑nian Dai The National Engineering Laboratory for Vacuum Metallurgy State Key Laboratory of Complex Nonferrous Metal Resources Clean UtilizationKunming University of Science and TechnologyKunming 650093YunnanChina College of Vanadium and Titanium Panzhihua UniversityPanzhihua 617000SichuanChina Key Laboratory for Nonferrous Vacuum Metallurgy of Yunnan Province Engineering Research Center for Silicon Metallurgy and Silicon Materials of Yunnan Provincial UniversitiesKunming University of Science and TechnologyKunming 650093YunnanChina

The effects of directional solidification parameters and the coupling of directional solidification parameters and alternating electromagnetic fields on separation and enrichment of the C54–TiSi2 phase were investigated in a directionally solidified hypoeutectic Ti–65 wt.%Si *** results indicated that by increasing the pull-down velocity at a given position within the ingot,the cooling rate,growth rate,and temperature gradient of ingot could be *** a pull-down velocity near 5μm/s,the temperature gradient,cooling rate,and growth rate decreased with increasing the thickness of the C54–TiSi2-rich *** fields enhanced mass transfer at pull-down velocities of 5,10,15,and 20μm/s,with resulting enriched layer thicknesses of 15,10,10,and 5 mm,*** increasing the percentage of Ti in the Ti–Si alloy from 25 to 35 wt.%,the thickness of the C54–TiSi2-rich layer was increased from 2.5 to 3.3 ***,the maximum C54–TiSi2 content obtained experimentally in this layer decreased from 92.06 to 79.49 mass%.

关键词： Ti–Si alloy Directional solidification Electromagnetic field Separation C54–TiSi2

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Boron removal from metallurgical-grade silicon by CaO–SiO_2 slag refining

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Rare Metals 2015年第7期34卷 522-526页

作者： kui-xian wei Hai-Fei Lu Wen-Hui Ma Yan-Long Li Zhao Ding Ji-Jun Wu Yong-Nian Dai The National Engineering Laboratory for Vacuum Metallurgy and State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization Kunming University of Science and Technology Key Laboratory for Nonferrous Vacuum Metallurgy of Yunnan Province and Engineering Research Center for Silicon Metallurgy and Silicon Materials of Yunnan Provincial Universities Kunming University of Science and Technology

Boron removal from metallurgical-grade silicon(MG-Si) using CaO–SiO2 slag was studied by employing a medium-frequency electromagnetic induction *** relationship between the optical basicity(K)of the CaO–SiO2 slag and the distribution coefficient of boron(LB) was ***, the local minimum and maximum LBvalues of 0.72 and 1.58 are obtained when K = 0.56 and K = 0.71, *** boron content in MG-Si decreases gradually with refinement time increasing, down to a minimum value of4.73 9 *** controlling step in the removal of boron from MG-Si is not the chemical reaction at the interface of the slag and ***, the controlling step is a diffusion mass transfer, in which boron impurities diffuse from molten silicon to the interface of the slag and silicon,or B2O3 formed by the chemical reaction diffuses from the slag–silicon interface to molten slag.

关键词： Metallurgical-grade silicon Boron removal Slag ref

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Recognition and rejection of foreign eggs of different colors in Barn Swallows

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Avian Research 2024年第3期15卷 374-378页

作者： kui Yan wei Liang Ministry of Education Key Laboratory for Ecology of Tropical Islands Key Laboratory of Tropical Animal and Plant Ecology of Hainan ProvinceCollege of Life SciencesHainan Normal UniversityHaikou571158China

Brood parasitic birds lay eggs in the nests of other birds,and the parasitized hosts can reduce the cost of raising unrelated offspring through the recognition of parasitic *** can adopt vision-based cognitive mechanisms to recognize foreign eggs by comparing the colors of foreign and host ***,there is currently no uniform conclusion as to whether this comparison involves the single or multiple threshold decision *** this study,we tested both hypotheses by adding model eggs of different colors to the nests of Barn Swallows(Hirundo rustica)of two geographical populations breeding in Hainan and Heilongjiang Provinces in *** showed that Barn Swallows rejected more white model eggs(moderate mimetic to their own eggs)and blue model eggs(highly non-mimetic eggs with shorter reflectance spectrum)than red model eggs(highly nonmimetic eggs with longer reflectance spectrum).There was no difference in the rejection rate of model eggs between the two populations of Barn Swallows,and clutch size was not a factor affecting egg *** results are consistent with the single rejection threshold *** study provides strong experimental evidence that the color of model eggs can has an important effect on egg recognition in Barn Swallows,opening up new avenues to uncover the evolution of cuckoo egg mimicry and explore the cognitive mechanisms underlying the visual recognition of foreign eggs by hosts.

关键词： Barn Swallow Egg color Hirundo rustica Multiple rejection threshold Single rejection threshold Visual recognition system

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Analysis of the breakage parameters of railway ballast based on the discrete element method

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2023年第3期24卷 257-271页

作者： Gan-zhong LIU Jia-cheng DAI Ping WANG Rong CHEN Hao LIU xian-kui wei MOE Key Laboratory of High-speed Railway Engineering Southwest Jiaotong UniversityChengdu 610031China School of Civil Engineering Southwest Jiaotong UniversityChengdu 610031China Amoy Transit Rail(AMTR) Xiamen MetroXiamen 361000China Railway Engineering Research Institute China Academy of Railway Sciences Corporation LimitedBeijing 100081China Shudao Investment Group Co.Ltd. Chengdu 610031China

During the service lives of ballasted tracks,the ballast experiences degradation,such as breakage and fragmentation,which reduces the stability of the *** breakage is directly related to the shapes,sizes,and stress states of *** key to solving this problem is to determine the breakage parameters of railway *** this study,through uniaxial compression and uniaxial shear tests,the factors associated with ballast breakage for a simple stress state were ***,a refined discrete element model of railway ballast was *** Box-Behnken method was used to design a simulation test,and a response surface method was used to obtain the optimal ballast breakage ***,the results of a direct shear test were compared with the simulation results to verify the correctness of the parameters and to study the shear resistance of the ballast *** results showed that for ballast particles with sizes of 22.4–63.0 mm,the characteristic stresses of compression and shear were not significantly affected by the size of the particles,but were greatly affected by their *** particular,long particles were more likely to *** the direct shear test,the cumulative ballast breakage ratio gradually increased to 13.97%.The optimal breakage parameters of the ballast determined by this approach have high application value in the management of ballasted tracks.

关键词： Ballasted track Breakage parameters Discrete element method(DEM) Response surface

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Viscoacoustic generalized screen propagator in constant-Q model

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Petroleum Science 2024年第4期21卷 2356-2369页

作者： Zhong-kui Dai Jia-Chun You Xing-Guo Huang wei Liu College of Geophysics Chengdu University of Technology College of Instrumentation and Electrical Engineering Jilin University

When seismic waves propagate through the geological formation, there is a significant loss of energy and a decrease in imaging resolution, because of the viscoacoustic properties of subsurface medium. This profoundly impacts seismic wavefield propagation, imaging and interpretation. To accurately image the true structure of subsurface medium, the consensus among geophysicists is to no longer treat subsurface medium as ideal homogeneous medium, but rather to incorporate the viscoacoustic properties of subsurface medium. Based on the generalized screen propagator using conventional acoustic wave equation(acoustic GSP), our developed method introduces viscoacoustic compensation strategy, and derives a one-way wave generalized screen propagator based on time-fractional viscoacoustic wave equation(viscoacoustic GSP). In numerical experiments, we conducted tests on two-dimensional multi-layer model and the Marmousi model. When comparing with the acoustic GSP using the acoustic data, we found that the imaging results of the viscoacoustic GSP using the viscoacoustic data showed a significant attenuation compensation effect, and achieved imaging results for both algorithms were essentially consistent. However, the imaging results of acoustic GSP using viscoacoustic data showed significant attenuation effects, especially for deep subsurface imaging. This indicates that we have proposed an effective method to compensate the attenuated seismic wavefield. Our application on a set of real seismic data demonstrated that the imaging performance of our proposed method in local areas surpassed that of the conventional acoustic GSP. This suggests that our proposed method holds practical value and can more accurately image real subsurface structures while enhancing imaging resolution compared with the conventional acoustic GSP. Finally, with respect to computational efficiency, we gathered statistics on running time to compare our proposed method with conventional Q-RTM, and it is evid

关键词： One-way wave equation Viscoacoustic wave equation Generalized screen propagator Attenuation and dispersion effects

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Particle distributions in Lamb wave based acoustofluidics

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Nanotechnology and Precision Engineering 2024年第2期7卷 60-68页

作者： Chuanchao Zhang xian Chen wei wei Xuejiao Chen Quanning Li Xuexin Duan Key Laboratory of Precision Measuring Technology and Instruments College of Precision Instrument and Optoelectronics EngineeringTianjin UniversityTianjin300072China

Acoustic streaming enabled by a Lamb wave resonator(LWR)is efficient for particle trapping and enrichment in microfluidic ***,because Lamb waves combine the features of bulk acoustic waves and surface acoustic waves,the resulting acoustic streaming in the LWR occurs in multiple planes,and the particle flow behavior in this acoustofluidic system is largely *** here are numerical simulations and laboratory experiments conducted to investigate the boundary conditions for particle motion inside a microvortex induced by an *** dynamic capture,the particles’trajectories become orbital paths within an acoustic *** suspended particles encounter two distinct acoustic phenomena,i.e.,the drag force resulting from acoustic streaming and the acoustic radiation force,which exert forces in various directions on the *** the acoustic radiation force and the fluid drag force are dominant for large and small particles in a mixed solution,respectively,the large particles reside within the vortex while the small particles remain at its ***,when the acoustic radiation force is dominant for both types of particles,the distribution pattern is reversed.

关键词： Acoustofluidics Lamb wave resonator Particle manipulation Microvortex

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Microstructure Evolution and Nanomechanical Behavior of Micro-Area in Molten Pool of Selective Laser Melting(CoCrNi)_(82)Al_(9)Ti_(9)High-Entropy Alloy

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Acta Metallurgica Sinica(English Letters) 2024年第6期37卷 1019-1033页

作者： Hong-wei Zhang Li-wei Lan Zhe-Yu Yang Chang-Chun Li Wen-xian Wang College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan030024China Ministry of Education Key Laboratory of Interface Science and Engineering in Advanced MaterialsTaiyuan University of TechnologyTaiyuan030024China Shanxi-Zhejiang University New Materials and Chemical Research Institute Taiyuan030032China

In this work,the phase evolution mechanism and nanomechanical properties of(CoCrNi))(82)Al_(9)Ti_(9)high-entropy alloy(HEA)prepared by selective laser melting(SLM)in the molten pool were *** HEA contains multiple primary elements and undergoes high-temperature gradient and rapid cooling during *** leads to significant inhomogeneity of nano-scale microstructure characteristics and instability of *** optimizing process parameters,the microstructure evolution at the optimal parameter volume energy density of 440 J/mm^(3)was studied.A phase transition from BCC to FCC occurred in the melt *** the micro-area of the melt pool results in a temperature rise and the combustion-induced loss of Al ***,the Ni element content increases significantly outside the melt *** process enhances the phase stability of FCC and facilitates phase ***,rapid cooling leads to the formation of distinctive ultrafine equiaxial crystals inside the melt pool,accompanied by the generation of intracrystalline needle-like nano-scale *** the melt pool,the accumulation of energy results in the formation of coarse ***,the nano-hardness inside the molten pool is remarkably high at 11.79 GPa,while the outside the molten pool is reduced to 9.58 *** the fracture toughness outside the melt pool also *** with inside the melt pool,the residual stress outside the melt pool changed from compressive to tensile stress and decreased from 603.28 to 322.84 MPa.

关键词： High-entropy alloys Selective laser melting Microstructure evolution Nanoindentation

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Hybrid vibration isolation optimization of a flexible manipulator based on neural network agent model

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Chinese Journal of Aeronautics 2024年第5期37卷 482-505页

作者： Yongxin ZHANG Liang LI Dingguo ZHANG wei-Hsin LIAO xian GUO School of Science Nanjing University of Science and TechnologyNanjing 210094China Department of Mechanical and Automation Engineering The Chinese University of Hong KongHong KongChina

Segmented Active Constrained Layer Damping(SACLD)is an intelligent vibration-damping structure,which could be applied to the sectors of aviation,aerospace,and transportation engineering to reduce the vibration of flexible ***,machine learning technology is widely used in the engineering field because of its efficient multi-objective *** dynamic simulation of a rotational segmental flexible manipulator system is presented,in which enhanced active constrained layer damping is carried out,and the neural network model of Genetic Algorithm-Back Propagation(GA-BP)algorithm is *** suppression and structural optimization of the SACLD manipulator model are studied based on vibration mode and damping *** modal responses of the SACLD manipulator model at rest and rotation are *** addition,the four model indices are optimized using the GA-BP neural network:axial incision size,axial incision position,circumferential incision size,and circumferential incision ***,the best model for vibration suppression is obtained.

关键词： Machine learning Vibration suppression Flexible manipulator Segmented active constrained layer damping Structural optimization

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Comprehensive analysis and mitigation strategies for safety issues of sodium-ion batteries

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Rare Metals 2024年第4期43卷 1343-1349页

作者： Tao wei Xiao-Ling xian Shi-Xue Dou wei Chen Shu-Lei Chou Institute for Carbon Neutralization College of Chemistry and Materials EngineeringWenzhou UniversityWenzhou325035China Wenzhou Key Laboratory of Sodium-Ion Batteries Wenzhou University Technology Innovation Institute for Carbon NeutralizationWenzhou325035China Zhejiang Key Laboratory of Carbon Materials College of Chemistry and Materials EngineeringWenzhou UniversityWenzhou325035China Institute for Superconducting and Electronic Materials Australian Institute for Innovative MaterialsUniversity of WollongongInnovation CampusWollongongNSW2522Australia

Sodium-ion batteries show great potential as an alternative energy storage system,but safety concerns remain a major hurdle to their mass *** paper analyzes the key factors and mechanisms leading to safety issues,including thermal runaway,sodium dendrite,internal short circuits,and gas *** promising solutions are proposed,such as high-safety electrode materials in the cathode and anode,high-safety electrolytes,and external battery management *** in also we emphasize the importance of selecting appropriate analysis methods and developing reliable failure models while suggesting advanced machine learning tools for *** a comprehensive approach,this study offers valuable recommendations to optimize materials and solutions for improving the safety of sodium-ion batteries.

关键词： Sodium-ion batteries Safety issues Thermal runaway Sodium dendrites

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