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Numerical Simulation of Three-dimensional Heat and Mass Transfer in Spray Cooling of Converter Gas in a Venturi Scrubber

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Chinese Journal of Mechanical Engineering 2009年第5期22卷 745-754页

作者： lu tao wang kuisheng School of Mechanical and Electrical Engineering Beijing University of Chemical Technology Beijing 100029 China

In order to predict the pressure drop, collection efficiency, velocity, temperature and mole fraction of vapor in an industrial venturi scrubber with water spraying for converter gas cooling, a three-dimensional model of heat and mass transfer with phase change is established. The gas flow and liquid droplets are treated as a continuous phase with a Eulerian approach and as a discrete phase with a Lagrangian approach, respectively. The coupled problem of heat, force, and mass transfers between gas flow and liquid droplets is solved by a commercial computational fluid dynamics（CFD） package, FluENT. The numerical results show that the water injections have an important influence on the distributions of pressure, velocity, temperature, and mole fraction of vapor, especially for the spraying region in the throat. In the spraying region, the pressure drop is higher and the velocity is lower than in other regions due to the gas-droplet drag, while the temperature is lower because the droplet absorbs large amounts of heat from the high temperature gas and the mole fraction of vapor is higher due to the phase change of the liquid droplet. A number of cases with different Water-to-gas volume flow ratios and baffle openings were simulated. The dependence of pressure drop, velocity, temperature, mole fraction of vapor, and collection efficiency on both the water-to-gas volume flow ratio and baffle opening are analyzed. The good agreements between simulation results and experiment data of pressure drop, temperature, and collection efficiency validate the model. The model should facilitate optimization of the venturi scrubber design in order to give better performance with lower pressure drops and higher collection efficiency.

关键词： numerical simulation heat and mass transfer spray cooling converter gas venturi scrubber

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Distribution and mapping of temperate savanna in the sandy lands of eastern China

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Science China Earth Sciences 2025年第1期68卷 128-141页

作者： Xiaoya LI Feng wang tao DUAN Kaijie YANG Bin YANG Chunmei wang Xin TIAN Qi lu Institute of Ecological Conservation and Restoration Institute of Desertification StudiesChinese Academy of ForestryBeijing100091China Institute of Desertification Institute of Desertification StudiesChinese Academy of ForestryBeijing100091China Institute of Great Green Wall Bayan Nur015200China Satellite Application Centre for Ecology and Environment MEEBeijing100094China Institute of Microelectronics Chinese Academy of SciencesBeijing100029China Aerospace Information Research Institute Chinese Academy of SciencesBeijing100094China Institute of Forest Resource Information Techniques Chinese Academy of ForestryBeijing100091China

Savannas are distributed globally across various *** perform a significant socioeconomic role in regulating net primary productivity and the terrestrial carbon *** to the high spatial heterogeneity induced by the mixed distribution of trees and grasses,current global land-cover classification maps often classify savannas as forests or grasslands Temperate savannas in China cover a vast area,yet their spatial patterns and extent remain poorly *** study developed a novel remote sensing temperate savannas mapping method by integrating very high-resolution(VHR)unmanned aerial vehicle(UAV)and GF-6 satellite imagery based on the vegetation structure characteristics of temperate savannas using the FAO definition of *** and validation datasets were collected from VHR UAV imagery covering the main temperate savannah types with a ground area of 1818 *** fractional woody vegetation cover(FWVC)and fractional herbaceous vegetation cover(FHVC)in temperate savannas were estimated by integrating Classification and Regression Tree and Random Forest *** current distribution of temperate savannas in the Horqin and Otindag Sandy Lands of Eastern China was mapped to a unit area of 0.5 *** root-mean-square error(RMSE)values for the FWVC and FHVC models were 10.69%and 11.67%,and the R^(2)values were 0.66 and 0.63,*** assessment indicated that the new temperate savanna map had high identification accuracy,with a Kappa coefficient of 0.70,overall accuracy of 0.88,and average accuracy of *** savannas in the sandy lands of eastern China were primarily distributed in the northern Horqin Sandy Land the central and eastern regions of the Otindag Sandy Land,and the transition zone from the southern slopes of the Greater Khingan Mountains to the plains,covering a total area of 3.27×10^(6)*** main savannah types were elm,oak/maple,and shrub *** savannas were widely distributed in the Otindag Sandy Land a

关键词： Temperate savanna UAV imagery GF-6 Fractional woody vegetation cover Fractional herbaceous vegetation cover Machine learning

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Surface ligand-promoted heterogeneous CO_(2) catalysis

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Science China Chemistry 2025年第2期68卷 444-457页

作者： Zhe lu lu wang School of Science and Engineering The Chinese University of Hong KongShenzhenShenzhen 518172China

Heterogeneous CO_(2) catalysis towards the synthesis of high-value products provides a potent pathway for achieving carbon *** distinctive attributes of surface ligands allow for highly effective tuning of the kinetics and mechanisms to enhance CO_(2) conversion *** this review,the catalytic contributions of surface ligands from the view of structure modulation,mechanism modulation,mass transfer,and energy transfer were *** relationships between surface ligands and the performance of functionalized catalysts were further ***,the applications of hydrocarbon chain spacer,hydroxyl and amino as terminal,and SiOx ligand in thermal,photo,and photothermal CO_(2) conversion were *** examining the current limitations and advancements,we concluded with insights into potential future research directions that focus on the development of precisely tuned active sites for highly efficient CO_(2) conversion.

关键词： heterogeneous catalysis CO_(2) conversion surface ligands

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Synthesis and high frequency structure simulator electromagnetic simulation of hollow NC@CeO_(2)nanospheres for broad absorption bandwidth

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International Journal of Minerals,Metallurgy and Materials 2025年第3期32卷 678-688页

作者： Shuhao Yang Peiyan Zhao Xianyong lu Xiaoyuan Hao Yufan Wu Huiya wang tao Zhou Guangsheng wang Hangzhou International Innovation Institute Beihang UniversityHangzhou 311115China School of Chemistry Beihang UniversityBeijing 100191China School of Materials Science and Engineering Zhejiang Sci-Tech UniversityHangzhou 310018China School of Chemistry and Chemical Engineering Lingnan Normal UniversityZhanjiang 524048China

Recent progress in microwave absorption materials stimulates the extensive exploration of rare earth oxide ***,we report the synthesis of a hollow sphere-based carbon material compounded with rare earth *** N-doped carbon nano-spheres loaded ceria composites(H-NC@CeO_(2))were designed and prepared by the template method,combined with in-situ coating,pyrolysis and chemical *** controlling the loading content of H-NC@CeO_(2)and adjusting the impedance matching of the material,the H-NC@CeO_(2)/PS(polystyrene)composite exhibited a minimum reflection loss(RL)of-50.8 dB and an effective absorption band-width(EAB)of 4.64 GHz at a filler ratio of 20wt%and a thickness of 2 *** accordance with measured electromagnetic parameters,simulations using the high frequency structure simulator(HFSS)software were conducted to investigate the impact of the honeycomb structure on the electromagnetic wave performance of H-NC@CeO_(2)/*** calculating the surface electric field and the material’s bulk loss density,the mechanism of electromagnetic loss for the honeycomb structure was elaborated.A method for structural design and man-ufacturing of broadband absorbing devices was proposed and a broadband absorber with an EAB of 11.9 GHz was *** study presents an innovative approach to designing advanced electromagnetic(EM)wave absorbing materials with broad absorption band-widths.

关键词： rare earth oxides carbon matrix composites hollow structure electromagnetic simulation

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Ultrasonic humidifier aerosols:Observed high heavy metal enrichment and a new emission control method

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Journal of Environmental Sciences 2025年第2期148卷 298-305页

作者： tao Zhang Xiaohui lu Ruoyu Zhang Xinghua Jiang Shanye Yang Xiewen Ma Qianqian Gao Xiaofei wang Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention Department of Environmental Science and EngineeringFudan UniversityShanghai 200433China Shanghai Institute of Pollution Control and Ecological Security Shanghai 200092China

Ultrasonic humidifiers are commonly used in households to maintain indoor humidity and generate a large number of droplets or spray ***,there have been various health concerns associated with humidifier use,largely due to aerosols generated during ***,we investigated the size distribution,chemical composition,and charged fraction of aerosol particles emitted from commercial ultrasonic *** metals in water used for humidifiers were found to be highly enriched in the ultrasonic humidifier aerosols(UHA),with the enrichment factors ranging from 102 to *** enrichment may pose health concerns for the building occupants,as UHA concentrations of up to 106 particles/cm^(3) or 3 mg/m^(3) were ***,approximately 90%of UHA were observed to be electrically charged,for the first time according to our *** on this discovery,we proposed and tested a newmethod to remove UHA by using a simple electrical *** designed electrical field in this work can efficiently remove 81.4%of ***,applying this electrical field could be an effective method to significantly reduce the health risks by UHA.

关键词： Ultrasonic humidifier aerosols Water-to-Air transfer Heavy metal Enrichment factor Electrical field

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Phase-transfer-shuttle generated in situ enables novel SN1-type fluorination of sulfonium ylide with hydrofluoric acid

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Science China Chemistry 2025年第2期68卷 641-648页

作者： Yisa Xiao Rui wang Zhaoxuan Xu Qunchao Zhao Renyi Pang tao Dong Long lu Qilong Shen Key Laboratory of Fluorine and Nitrogen Chemistry and Advanced Materials Shanghai Institute of Organic ChemistryUniversity of Chinese Academy SciencesChinese Academy of SciencesShanghai 200032China

The development of a nucleophilic fluorination protocol using hydrofluoric acid as the fluoride source represents a long-sought goal in the field of organofluorine *** report herein the realization of such a reaction that employed alkyl-substituted sulfonium ylides as the *** key to the success of the protocol was attributed to two factors:First,as a Brϕnsted base,the ylide was able to be protonated by HFaq,thus serving as a phase-transfer shuttle generated in situ to bring F−from aqueous phase to the organic phase promoting desolvation of fluoride ***,after protonation,a sulfonium salt,a good leaving group,was generated and subsequent attacked by the fluoride to afford the alkyl *** investigation indicates that the reaction occurs via an SN1 *** of the nature of the cationic intermediate in the reaction,two attractive rearrangement-fluorination approaches including 1,2-aryl migration fluorination and ring-expansion fluorination were disclosed.

关键词： SN1 fluorination hydrofluoric acid sulfonium ylide cation rearrangement

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Synthesis of ordered mesoporous crystalline boron phosphate scaffold with double diamond surface structure

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Science China Chemistry 2025年第2期68卷 590-600页

作者： Chao wang Wen-Duo lu Jiao wang Shunai Che An-Hui lu lu Han School of Chemical Science and Engineering Tongji UniversityShanghai 200092China State Key Laboratory of Fine Chemicals Liaoning Key Laboratory for Catalytic Conversion of Carbon ResourcesSchool of Chemical EngineeringDalian University of TechnologyDalian 116024China School of Chemistry and Chemical Engineering Frontiers Science Center for Transformative MoleculesState Key Laboratory of Metal Matrix CompositesShanghai Key Laboratory for Molecular Engineering of Chiral DrugsShanghai Jiao Tong UniversityShanghai 200240China

Ordered mesoporous materials have received great attention due to their well-defined pore structures and potential applications in catalysis,adsorption,separation,drug delivery,*** various compositions of mesoporous solids have been successfully prepared,the preparation of crystalline non-metallic oxyacid salts with ordered mesoporosity remains a major ***,we report the synthesis of a mesoporous solid acid crystalline boron phosphate(BPO_(4))catalyst with a bicontinuous shifted double diamond(SDD)hyperbolic surface *** BPO_(4) scaffold was obtained by synergistic selfassembly in a mixed solvent of water and tetrahydrofuran using the diblock copolymer poly(ethylene oxide)-block-polystyrene as template and phosphoric acid and orthoboric acid as inorganic *** structure consists of two sets of diamond networks adjacent to each other with a mesostructural scale tetragonal symmetry(space group I4_(1)/amd)with unit cell parameters of a=80 nm and c=113 nm,which affords the scaffold a specific surface area of 44 m^(2)/*** a solid acid catalytic material,the SDD BPO_(4) scaffold exhibited excellent catalytic activity at room temperature with a conversion of furfural to 2-(dimethoxymethyl)furan over 70%and can be reused after recovery without serious loss of *** the propane oxidative dehydrogenation reaction,SDD BPO_(4) demonstrated high olefin productivity and selectivity while maintaining high reaction *** study provides ideas for the preparation of ordered mesoporous crystalline catalytic materials and demonstrates their potential for practical applications.

关键词： boron phosphate mesoporous material self-assembly block copolymer catalyst

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Unraveling the complex interactions between plasmonic Ag nanoparticles and biomolecules for enhancing molecular chirality

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Science China Chemistry 2025年第2期68卷 543-551页

作者： Chen wang Yunlong tao Qingqing Cheng Dandan lu Chuang Liu Guizeng Yang Xuehao Sun Lichao Sun Qingfeng Zhang College of Chemistry and Molecular Sciences Hubei Key Laboratory of Electrochemical Power SourcesWuhan UniversityWuhan 430072China Suzhou Institute of Wuhan University Suzhou 215123China

Plasmonic nanostructures have been widely employed to enhance the chiral light-matter interactions for chirality sensing owing to their intriguing optical ***,a quantitative understanding of the correlation between enhanced molecular chirality and plasmonic properties in plasmonic nanoparticle-molecule complexes remains a challenge yet to be *** we demonstrate the complex interactions between Ag nanoparticles and biomolecules that generate distinct plasmonic circular dichroism signals ranging from UV to visible *** deliberately changing the surface coverage of chiral molecules,the geometry of Ag nanoparticles,and the aggregation states of the complexes,three distinct underlying mechanisms were found to be intertwined and hybridized for enhancing circular dichroism *** further employed the chiral plasmonic nanoparticle-molecule complexes to quantify the enantiomeric purity of cysteine and explore their possible applications in other chiral *** insights gained from this work shed light on the underlying mechanisms dictating the enhanced circular dichroism signals of chiral plasmonic nanoparticle-molecule complexes.

关键词： chiral plasmonics plasmonic circular dichroism nanoparticle-molecule complexes Ag nanoparticles chirality sensing

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Platinum modification of metallic cobalt defect sites for efficient electrocatalytic oxidation of 5-hydroxymethylfurfural

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Journal of Energy Chemistry 2025年第2期101卷 463-473页

作者： Haoyu Zhan Baixue Cheng Yankun lu Danning Xing Xingshuai Lv Huining Huang Thomas Frauenheim tao wang Peng Zhou State Key Laboratory of Bio-fibers and Eco-textiles College of Materials Science and Engineering Collaborative Innovation Center of Shandong Marine Biobased Fibers and Ecological Textiles Institute of Marine Biobased Materials Qingdao University Shandong Institute of Advanced Technology College of Chemistry and Chemical Engineering Ocean University of China Tianjin Key Laboratory of Advanced Functional Porous Materials Institute for New Energy Materials & Low-Carbon Technologies School of Materials Science and EngineeringTianjin University of Technology School of Science Constructor University Beijing Computational Science Research Center College of Chemistry and Molecular Engineering Qingdao University of Science and Technology

Co3O4possesses both direct and indirect oxidation effects and is considered as a promising catalyst for the oxidation of 5-hydroxymethylfurfural（HMF）.However,the enrichment and activation effects of Co3O4on OH-and HMF are weak,which limits its further *** defect engineering can regulate the electronic structure,optimize the adsorption of intermediates,and improve the catalytic activity by breaking the symmetry of the material,which is rarely involved in the upgrading of *** this work,we prepare Co3O4with metal defects and load the precious metal platinum at the defect sites（PtVco）.The results of in-situ characterizatio ns,electrochemical measurements,and theoretical calculations indicate that the reduction of Co-Co coordination number and the formation of Pt-Co bond induce the decrease of electron filling in the antibonding orbitals of Co *** resulting upward shift of the d-band center of Co combined with the characteristic adsorption of Pt species synergically enhances the enrichment and activation of organic molecules and OH species,thus exhibiting excellent HMF oxidation activity(including a lower onset potential（1.14 V） and 19 times higher current density than pure Co3O4at 1.35 V).In summary,this work explores the adsorption enhancement mechanism of metal defect sites modified by precious metal in detail,provides a new option for improving the HMF oxidation activity of cobalt-based materials,broadens the application field of metal defect based materials,and gives an innovative guidance for the functional utilization of metal defect sites in biomass conversion.

关键词： Adsorption enhancement Biomass upgrading Coordination environment Electrocatalysis Metallic defect

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No-go guide for the Hubble tension:Late-time or local-scale new physics

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Science China(Physics,Mechanics & Astronomy) 2025年第2期68卷 73-85页

作者： lu Huang Shao-Jiang wang wang-Wei Yu CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of Sciences(CAS)Beijing100190China Asia Pacific Center for Theoretical Physics(APCTP) Pohang37673Korea Max-Planck-Institut für Gravitationsphysik(Albert-Einstein-Institut) HannoverD-30167Germany Leibniz Universität Hannover Hannover30167Germany

The standard model of modern cosmology might be cracked by the recent persistent hot debate on the Hubble-constant(H_(0))tension,which manifests itself as the sound-horizon(r_(s))tension or absolute-magnitude(M_(B))tension if deeming the origin of the Hubble tension from modifying the early or late Universe,*** this study,we achieve a fully model-independent constraint(fitting a model-independent global parameterization to a model-independent inverse distant ladder with a modelindependent high-redshift calibration)on late-time models with strong evidence against homogeneous new physics over theΛ-cold-dark-matter(ΛCDM)*** using this model-independent constraint to calibrate sufficiently local supernovae with corresponding late-time models extrapolated below the homogeneity scale,we find surprisingly that,although both H_(0)tension and MB tension are absent in our local Universe,a combination of H_(0)and M_(B)as the intercept a B of the magnitude-redshift relation exhibits 3~7σtension even for theΛCDM *** aBtension seems to call for local-scale inhomogeneous new physics disguised as local observational systematics.

关键词： Hubble constant inverse distance ladder local Universe

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