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A Theoretical Model of Arc Light Radiation Based on GTA Spectral Diagnosis

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Journal of Materials Science & Technology 2003年第Z1期19卷 99-100页

作者： Chenming XU Hongming GAO guangjun ZHANG Lin wu State Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 China State Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 China State Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 China State Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 China

An arc light radiation phenomenon in TIG welding process was studied through experiments and theoretical *** arc spectra were acquired under a variety of welding parameters from 200 nm to 1000 nm wavelength rangein TIG. The influence of welding parameters on the arc radiation was discussed. The radiation energy from linesemission mechanisms was calculated and the comparison was made with the one from the continuum emissionmechanisms. The result shows that the radiation energy from the line emission mechanisms is equal to the one fromthe background. Based on the experiments and analysis, a physical model of arc light radiation has been *** this model. the arc plasma was presumed to be in local thermal equilibrium (LTE) with light thinness *** Bolzmann distribution and Saha equation were applied to establish the arc light radiation model. This helps laythe foundation for further mathematical modeling of the arc light radiation.

关键词： Spectral diagnosis, Arc light radiation, Theoretical model, TIG

Reconstruction of Emission Coefficients for a Non-axisymmetric Coupling Arc Based on MALDONADO's Method

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Chinese Journal of Mechanical Engineering 2012年第4期25卷 781-785页

作者： XIONG Jun ZHANG guangjun HU Yutang wu Lin State Key Laboratory of Advanced Welding and Joining Harbin Institute of Technology Harbin 150001 China

The reconstruction of emission coefficient is a key factor for the calculation of temperature ***,most of the researches for determining arc plasmas are based on axisymmetric sources,little has been done to study non-axisymmetric arc *** order to reveal temperatures of a non-axisymmetric coupling arc,the distribution of emission coefficients must be reconstructed in *** this paper,the argon atomic line intensities of the coupling arc are obtained by using the imaging system that involves a high speed camera in conjunction with a neutral and a narrow-band *** converted programme between emission coefficients and emitted intensities is programmed based on MALDONADO＇s method.A displaced Gaussian model is used for evaluating the validity of the converted ***,the emission coefficients of a free burning arc are reconstructed by MALDONADO＇s method and an Abel inversion,respectively,and good agreement is ***,the emission coefficient profiles of the coupling arc are *** results show that the distribution of emission coefficient for the coupling arc is *** emission coefficient profile is similar to an ellipse,and the short axis of the ellipse is in the direction that the two electrodes are arranged *** peak temperature of the coupling arc is in the middle of both *** is a strong interaction between both arcs within the coupling *** proposed research solves difficulties for determining asymmetric arcs and enlarges the application scope of spectroscopic techniques.

关键词： non-axisymmetric coupling arc emission coefficient Twin-electrode TIG spectroscopy image

Catalytic Hydration of Aromatic Alkynes to Ketones over H-MFI Zeolites

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Chemical Research in Chinese Universities 2022年第1期38卷 173-180页

作者： ZHANG Yunzhe DAI Weili wu guangjun GUAN Naijia LI Landong School of Materials Science and Engineering Nankai UniversityTianjin 300350P.R.China

The hydration of alkyne represents the most straightforward and simplest route toward the synthesis of ketone. Herein, Brønsted acidic zeolites are explored as potential catalysts for the liquid-phase phenylacetylene hydration. The topology structure and Si/Al ratio are disclosed to be key factors controlling the catalytic activity of zeolites. Typically, H-MFI zeolite with a Si/Al molar ratio of 13 exhibits the highest catalytic activity, with turnover frequency of 6.0 h-1 at 363 K. Besides, H-MFI zeolite shows good catalytic stability and recyclability in the reaction of phenylacetylene hydration, and the substrate scope can be simply extended to other soluble aromatic alkynes. The reaction mechanism of phenylacetylene hydration is investigated by means of kinetic and spectroscopic analyses. The Markovnikov electrophilic addition of phenylacetylene by hydrated protons is established as the rate-determining step, followed by deprotonation and enol isomerization to derive acetophenone product.

关键词： Phenylacetylene Catalytic hydration Zeolite Brønsted acid site H-MFI

Efficient nitric oxide capture and reduction on Ni-loaded CHA zeolites

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Green Energy & Environment 2024年第12期9卷 1857-1865页

作者： Bin Yue Jianhua Wang Shanshan Liu guangjun wu Bin Qin Landong Li School of Materials Science and Engineering Nankai UniversityTianjin300350China College of Chemistry Nankai UniversityTianjin300071China

As a prominent contributor to air pollution,nitric oxide(NO)has emerged as a critical agent causing detrimental environmental and health *** mitigate emissions and facilitate downstream utilization,adsorption-based techniques offer a compelling approach for direct NO capture from both stationary and mobile *** this study,a comprehensive exploration of NO capture under oxygen-lean and oxygenrich conditions was conducted,employing Ni ion-exchanged chabazite(CHA-type)zeolites as the ***,Ni/Na-CHA zeolites,with Ni loadings ranging from 3 to 4 wt%,demonstrate remarkable dynamic uptake capacities and exhibit exceptional NO capture efficiencies(NO-to-Ni ratio)for both oxygen-lean(0.17-0.31 mmol/g,0.32-0.43 of NO/Ni)and oxygen-rich(1.64-1.18 mmol/g)under ambient *** NH3 reduction methodology was designed for the regeneration of absorbents at a relatively low temperature of 673 *** insights into the NO_(x) adsorption mechanism were obtained through temperature-programmed desorption experiments,in situ Fourier transform infrared spectroscopy,and density functional theory *** is unveiled that NO and NO_(2) exhibit propensity to coordinate with Ni^(2+) via N-terminal or O-terminal,yielding thermally stable complexes and metastable species,respectively,while the low-temperature desorption substances are generated in close proximity to Na^(+).This study not only offers micro-level perspectives but imparts crucial insights for the advancement of capture and reduction technologies utilizing precious-metal-free materials.

关键词： Nitrogen oxides Capture Zeolite Lean/rich condition Adsorption mechanism

Zeolites for separation:Fundamental and application

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Journal of Energy Chemistry 2022年第8期31卷 288-303,I0008页

作者： Bin Yue Shanshan Liu Yuchao Chai guangjun wu Naijia Guan Landong Li Haihe Laboratory of Sustainable Chemical Transformations School of Materials Science and EngineeringNankai UniversityTianjin 300350China Frontiers Science Center for New Organic Matter&Key Laboratory of Advanced Energy Materials Chemistry of Ministry of Education College of ChemistryNankai UniversityTianjin 300071China

Material based emerging separation techniques are attracting more and more attention as alternatives to the traditional ones such as distillation and extraction,aiming to reduce energy consumption and pollutant *** to their structure characteristics,zeolites can act as versatile sieves and adsorbents for molecules and have been successfully applied in some very important separation ***,two major catalogues of zeolite separations,namely membrane separation and adsorptive separation,are discussed and their underlying mechanisms are *** the part of membrane separation,the synthesis strategies toward zeolite membranes are introduced and the uniformly-oriented zeolite membranes are *** the part of the adsorptive separation,the industrial and popular adsorptive separations with the corresponding zeolite adsorbents are ***,membrane separation relies on the molecular diffusion behavior within zeolites while adsorptive separation relies on the guest–host interaction in *** key challenges and misconceptions in zeolite separations are highlighted throughout the article.

关键词： Zeolite Membrane separation Adsorptive separation Molecular diffusion Guest-host interaction

Multifunctional heteroatom zeolites:construction and applications

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Frontiers of Chemical Science and Engineering 2021年第6期15卷 1462-1486页

作者： Qifeng Lei Chang Wang Weili Dai guangjun wu Naijia Guan Landong Li School of Materials Science and Engineering&National Institute for Advanced Materials Nankai UniversityTianjin300350China Key Laboratory of Advanced Energy Materials Chemistry of the Ministry of Education Nankai UniversityTianjin300071China

Multifunctional heteroatom zeolites have drawn broad attentions due to the possible synergistic effects in the catalytic *** achievements have been made on the synthesis,characterization and catalytic applications of multifunctional heteroatom zeolite,while a review on this important topic is still ***,current research status of multifunctional heteroatom zeolites is briefly summarized,aiming to boost further ***,the synthesis strategies toward heteroatom zeolites are introduced,including the direct synthesis and postsynthesis routes;then,the spectroscopic techniques to identify the existing states of heteroatom sites and the corresponding physiochemical properties are shown and compared;finally,the catalytic applications of multifunctional heteroatom zeolites in various chemical reactions,especially in one-step tandem reactions,are discussed.

关键词： zeolite multifunctional active sites heteroatom characterization catalysis

A novel approach to design microwave medium of negative refractive index and simulation verification

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Chinese Science Bulletin 2007年第4期52卷 433-439页

作者： CAO YunJian WEN guangjun wu KaiMin XU XinHe School of Communication and Information Engineering University of Electronic Science and Technology of China Chengdu 610054 China

In this paper, a novel approach is presented to synthesize microwave medium of negative refractive index by incorporating metallic wire array with negative effective permittivity into the host media such as ferrimagnet-YIG (yttrium iron garnet) applied by external magnetic field whose permeability is negative. We have designed the composite medium having negative refractive index in C/X band frequencies, analyzed and simulated its electromagnetic (EM) properties by use of EM EDA package based on time-domain finite integration method. The simulation results show that: ① the effective permittivity of the designed metallic wire array is negative in the frequency range from 7.02 GHz to 9.80 GHz; ② the permeability of YIG substrate immersed into an external magnetic field is negative in the frequency range from 5.22 GHz to 8.14 GHz; ③ EM wave can pass through the composite medium synthesized by the above designed metallic wire array and YIG substrate, and ④ the negative refraction behavior occurs on the interface between the composite medium and the normal material with positive refractive index in 7.51―8.13 GHz frequency range, in which the effective permittivity of the metallic wire array and the permeability of YIG substrate are negative simultaneously. The full wave simulation has demonstrated that the effective refractive index of the designed composite medium is indeed negative and ascertained that the proposed approach to design microwave medium with negative refractive index is viable.

关键词：铁氧磁材料铁磁材料负折射率微波介质设计模拟验证电磁性质

Zeolite-encaged mononuclear copper centers catalyze CO2 selective hydrogenation to methanol

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National Science Review 2023年第7期10卷 134-141页

作者： Yuchao Chai Bin Qin Bonan Li Weili Dai guangjun wu Naijia Guan Landong Li Key Laboratory of Advanced Energy Materials Chemistry of Ministry of Education College of Chemistry Nankai University CAS Key Laboratory of Science and Technology on Applied Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences School of Materials Science and Engineering Nankai University

The selective hydrogenation of CO2to methanol by renewable hydrogen source represents an attractive route for CO2recycling and is carbon *** catalysts with high activity and methanol selectivity are being vigorously pursued,and current debates on the active site and reaction pathway need to be ***,we report a design of faujasite-encaged mononuclear Cu centers,namely Cu@FAU,for this challenging *** methanol space-time-yield（STY） of 12.8 mmol gcat-1h-1and methanol selectivity of 89.5% are simultaneously achieved at a relatively low reaction temperature of 513 K,making Cu@FAU a potential methanol synthesis catalyst from *** zeolite-encaged mononuclear Cu centers as the destined active sites,the unique reaction pathway of stepwise CO2hydrogenation over Cu@FAU is *** work provides a clear example of catalytic reaction with explicit structure-activity relationship and highlights the power of zeolite catalysis in complex chemical transformations.

关键词： CO2 hydrogenation zeolite methanol catalysis mononuclear copper

Optimizing zeolite stabilized Pt-Zn catalysts for propane dehydrogenation

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Journal of Energy Chemistry 2021年第6期30卷 92-98,I0003页

作者： Linjun Xie Yuchao Chai Lanlan Sun Weili Dai guangjun wu Naijia Guan Landong Li School of Materials Science and Engineering&National Institute for Advanced Materials Nankai UniversityTianjin 300350China Key Laboratory of Advanced Energy Materials Chemistry of Ministry of Education Nankai UniversityTianjin 300071China

Propane dehydrogenation(PDH)provides an alternative route to non-petroleum based propylene and eligible catalysts with good overall performance are still being ***,we report the construction of zeolite stabilized Pt-Zn catalysts Pt-Zn/Si-Beta for *** results from transmission electron microscopy(TEM),ultraviolet-visible(UV-vis)and Fourier transform infrared(FTIR)spectroscopy reveal that highly-dispersed Zn species are stabilized by the silanols from zeolite framework dealumination,which then act as the anchoring sites for Pt *** close contact between Pt-Zn species and the electronic interaction thereof make Pt-Zn/Si-Beta robust PDH *** optimized conditions,a high propylene production rate of 4.11 molmol_(Pt)^(-1)s^(-1),high propylene selectivity of 98% and a sustainable deactivation rate of~0.02 h^(-1)can be simultaneously achieved at 823 *** deposition is not the key reason for the catalytic deactivation,while the loss of Zn species and the resulting aggregation of Pt species under high temperatures are responsible for the irreversible deactivation of Pt-Zn/Si-Beta catalyst in PDH reaction.

关键词： Propane dehydrogenation Zeolite Pt-Zn/Si-Beta Deactivation