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Science China Chemistry 2013年第10期56卷 1478-1484页

作者： zhang zekai zhang BinHao LIU HuaYan CHEN YinFei Department of Industry Catalysis Zhejiang University of Technology

A series of Fe-Y zeolite catalysts with different Fe loading were prepared by ferrocene sublimation under solvent and wa- ter-free conditions. The dispersion, structure and morphology of the iron species on the Fe-Y catalysts were characterized by XRD, TEM and UV-Vis. The catalytic activities of Fe-Y samples were measured in selective catalytic redaction of NO with ammonia （NH3-SCR）. The results showed that the iron species on the HY zeolite support were mainly made up of isolated Fe3＋ ions, FexOy oligomers and a little amount of 〈 3 nm spherical Fe203 particles. Isolated Fe3＋ ions are predominating among all the Fe-Y catalysts. The sum of isolated Fe3＋ ions and FexOy oligomers took up more than 90% percent of total iron species on the Fe-Y till 10.0 wt% loading of Fe.

关键词： SCR NOx ferrocene Fe-Y water-free

Mayenite supported perovskite monoliths for catalytic combustion of methyl methacrylate

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Frontiers of Chemical Science and Engineering 2014年第1期8卷 87-94页

作者： zekai zhang Zhijian KONG Huayan LIU Yinfei CHEN College of Chemical Engineering and Materials Science Zhejiang University of Technology Hangzhou 310014 China

To improve their thermal stability, La0.8Sr0.2MnO3 cordierite monoliths are washcoated with mayenite, which is a novel Al-based material with the crystal structure of 12MO 7Al2O3 （M= Ca, Sr）. The monoliths are characterized by means of nitrogen adsorp- tion/desorption, scanning electron microscopy, and X-ray diffraction. Catalytic performances of the monoliths are tested for methyl methacrylate combustion. The results show that mayenite obviously improves both the physic- chemical properties and the catalytic performance of the monoliths. Because mayenite improves the dispersity of ***.2MnO3 and also prevents the interaction between La0.8Sr0.2MnO3 and cordierite or γ-A1203, both crystal structure and surface morphology of La0.8Sr0.2MnO3 phase can thereby be stable on the mayenite surface even at high temperature up to 1050 ℃. Under the given reaction conditions, La0.8Sr0.2MnO3 monolith washcoated with 12SrO. γ-A1203 shows the best catalytic activity for methyl methacrylate combustion among all the tested monoliths.

关键词： mayenite perovskite catalytic combustion,methyl methacrylate monolith

An Algebraic Multigrid-Based Physical Factorization Preconditioner for the Multi-Group Radiation Diffusion Equations in Three Dimensions

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Numerical Mathematics(Theory,Methods and Applications) 2023年第2期16卷 410-432页

作者： Xiaoqiang Yue zekai zhang Xiaowen Xu Shuying Zhai Shi Shu National Center for Applied Mathematics in Hunan Key Laboratory of Intelligent Computing&Information Processing of Ministry of EducationHunan Key Laboratory for Computation and Simulation in Science and EngineeringXiangtan UniversityXiangtan 411105China Laboratory of Computational Physics Institute of Applied Physics and Computational MathematicsBeijing 100094China School of Mathematical Sciences Huaqiao UniversityQuanzhou 362021China.

The paper investigates the robustness and parallel scaling properties of a novel physical factorization preconditioner with algebraic multigrid subsolves in the iterative solution of a cell-centered finite volume discretization of the threedimensional multi-group radiation diffusion *** key idea is to take advantage of a particular kind of block factorization of the resulting system matrix and approximate the left-hand block matrix selectively spurred by parallel processing *** spectral property of the preconditioned matrix is then *** practical strategy is considered sequentially and in ***,numerical results illustrate the numerical robustness,computational efficiency and parallel strong and weak scalabilities over the real-world structured and unstructured coupled problems,showing its competitiveness with many existing block preconditioners.

关键词： Radiation diffusion equations physical factorization preconditioning algebraic multigrid parallel and distributed computing

Acidity effects of Hβ zeolite on olefin alkylation of thiophenic sulfur in gasoline

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Journal of Natural Gas Chemistry 2008年第1期17卷 45-50页

作者： zekai zhang Dong Liu Xiangxue Zhu Haiwei Yu Shenglin Liu Longya Xu State Key Laboratory of Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 Liaoning China Dalian Petrochemical Corporations CNPC Dalian 116032 Liaoning China The Graduate University of Chinese Academy of Science Beijing 100049 China

Olefin alkylation of thiophenic sulfur process was carried out in model gasoline, using Hβ zeolites with different Si/Al2 ratios as catalysts. In particular, the influence of acid properties of Hβ zeolites on its catalytic ability for the thiophene alkylation, xylene alkylation and hexene oligomerization was investigated. The results showed that the acidity of the Hβ zeolite was increased with the decrease of Si/Al2 ratio, but its catalytic ability was not always increased. In fact, it reached the maximal catalytic ability at Si/Al2 ratio of 66, and under the reaction conditions of 60 ℃, 1.5 MPa, WHSV 3.0 h^-1 and time on stream 2 h. At the ratio, the conversion of thiophene, xylene, and oligomerized hexene were 96.6%, 2.7% and 2.8%, respectively. An optimal Si/Al2 ratio exists for the catalytic performance of Hβ zeolite. By investigating the coke deposition of the used Hβ zeolite catalysts, it has been found that the optimal Si/Al2 ratio is attributed to the combined effect of the carbocation activation capability and the hydrogen transformation capability of the Hβ zeolite catalyst.

关键词： desulfurization alkylation acidity Hβ gasoline

Multi-scale simulation of diffusion behavior of deterrent in propellant

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Chinese Journal of Chemical Engineering 2023年第2期54卷 29-35页

作者： Pan Huang zekai zhang Yuxin Chen Changwei Liu Yong zhang Cheng Lian Yajun Ding Honglai Liu State Key Laboratory of Chemical Engineering Shanghai Engineering Research Center of Hierarchical NanomaterialsSchool of Chemical EngineeringEast China University of Science and TechnologyShanghai 200237China School of Chemistry and Molecular Engineering East China University of Science and TechnologyShanghai 200237China School of Chemistry and Chemical Engineering Nanjing University of Science and TechnologyNanjing 210094China

Concentration distribution of the deterrent in single-base propellant during the process of firing plays an important role in the ballistic properties of gun propellant in weapons. However, the diffusion coefficient calculated by molecular dynamics(MD) simulation is 6 orders of magnitude larger than the experimental values. Meanwhile, few simple and comprehensive theoretical models can explain the phenomenon and accurately predict the concentration distribution of the propellant. Herein, an onion model combining with MD simulation and finite element method of diffusion in propellants is introduced to bridge the gap between the experiments and simulations, and correctly predict the concentration distribution of deterrent. Furthermore, a new time scale is found to characterize the diffusion process. Finally, the time-and position-depended concentration distributions of dibutyl phthalate in nitrocellulose are measured by Raman spectroscopy to verify the correctness of the onion model. This work not only provides guidance for the design of the deterrent, but could be also extended to the diffusion of small molecules in polymer with different crystallinity.

关键词： Multi-scale simulation Diffusion Deterrent Propellant Onion model Molecular dynamics simulation

Pd/Hβ-zeolite catalysts for catalytic combustion of toluene:Effect of SiO_2/Al_2O_3 ratio

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Journal of Natural Gas Chemistry 2010年第4期19卷 417-421页

作者： zekai zhang Longya Xu Zhanlong Wang Yujuan Xu Yinfei Chen College of Chemical Engineering and Materials Science Zhejiang University of Technology Hangzhou 310014 Zhejiang China Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 Liaoning China

The effect of pure and high silica Hβ zeolites on the catalytic performance of toluene combustion over Pd/Hβ catalyst was *** and high silica β zeolites were prepared by direct synthesis procedures,then 0.1 wt% of palladium was impregnated on different Hβ zeolites via in-cipient wetness technique using palladium nitrate as the Pd *** Pd/Hβ catalysts were characterized by XRD,N2 adsorption/desorption,H2O adsorption,NH3-TPD,H2-TPR and XPS *** increasing the SiO2/Al2O3 ratio of β zeolite,the activity of the Pd/Hβ catalysts for toluene combustion increased clearly and the pure silica β zeolite supported Pd catalyst showed the best catalytic *** superior catalytic performance of Pd/β catalyst prepared from pure silica β zeolite was attributed to its high hydrophobicity and the preserving ability for PdO active species.

关键词： pure silica β zeolite PdO hydrophobicity toluene

Pulsar Candidate Classification Using a Computer Vision Method from a Combination of Convolution and Attention

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Research in Astronomy and Astrophysics 2023年第10期23卷 192-200页

作者： Nannan Cai Jinlin Han Weicong Jing zekai zhang Dejiang Zhou Xue Chen National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China School of Astronomy University of Chinese Academy of SciencesBeijing 100049China CAS Key Laboratory of FAST NAOCChinese Academy of SciencesBeijing 100101China Department of Physics Boston CollegeMassachusetts 02467USA

Artificial intelligence methods are indispensable to identifying pulsars from large amounts of *** develop a new pulsar identification system that utilizes the CoAtNet to score two-dimensional features of candidates,implements a multilayer perceptron to score one-dimensional features,and relies on logistic regression to judge the corresponding *** the data preprocessing stage,we perform two feature fusions separately,one for one-dimensional features and the other for two-dimensional features,which are used as inputs for the multilayer perceptron and the CoAtNet *** newly developed system achieves 98.77%recall,1.07%false positive rate(FPR)and 98.85%accuracy in our GPPS test set.

关键词： (stars:)pulsars:general methods:data analysis techniques:image processing

Catalytic combustion of VOCs on Pt/CuMnCe and Pt/CeY honeycomb monolithic catalysts

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Journal of Rare Earths 2018年第12期36卷 1272-1277页

作者： Anming Zhu Ying Zhou Yue Wang Qiulian Zhu Huayan Liu zekai zhang Hanfeng Lu Innovation Team of Air Pollution Control College of Chemical Engineering Institute of Catalytic Reaction Engineering Zhejiang University of Technology

The metal oxides CuMnCe and CeY washcoats on cordierite were prepared using an impregnation method, and then used as support for the active Pt component to prepare the Pt/CuMnCe and Pt/CeY monolithic catalysts for the deep oxidation of VOCs. In comparison with the Pt/CeY, CuMnCe, and CeY monolithic catalysts, the Pt/CuMnCe monolithic catalyst shows an excellent performance for toluene,ethyl acetate,and n-hexane oxidation and the Tis low to 216, 200 and 260 ℃,respectively. The active components Pt/PtO and CuMnCe result in a better synergetic interaction, which promote the catalyst reducibility, increase the oxygen mobility, and enhance the adsorption and activation of organic molecules.

关键词： Catalytic combustion Volatile organic compounds Monolithic catalysts Pt catalyst Cu-Mn-Ce mixed oxides

A multifunctional electrolyte additive for zinc-ion capacitors with low temperature resistant and long lifespan

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Journal of Energy Chemistry 2024年第7期94卷 477-485页

作者： Ming Sun zekai zhang Shuqing Fu Yifan zhang Ruoyu Wang Hongchun Mu Cheng Lian Wenqiang Wang Gengchao Wang Shanghai Engineering Research Center of Hierarchical Nanomaterials Shanghai Key Laboratory of Advanced Polymeric MaterialsSchool of Materials Science and EngineeringEast China University of Science and TechnologyShanghai 200237China State Key Laboratory of Chemical Engineering Shanghai Engineering Research Center of Hierarchical NanomaterialsFrontiers Science Center for Materiobiology and Dynamic Chemistryand School of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai 200237China State Key Laboratory of Molecular Engineering of Polymers Department of Macromolecular ScienceFudan UniversityShanghai 200438China

Aqueous zinc-ion capacitors (ZICs) are considered as potential candidates for next generation electrochemical energy storage devices due to their high safety and low ***,the existing aqueous ZICs usually have the problems of zinc dendrite growth and unsatisfactory performance at low ***,an erythritol (Eryt) additive with inhibition of zinc dendrites and anti-freezing capability was introduced into the *** experimental characterization and theoretical calculation confirm that the Eryt adsorbed on the surface of zinc anodes regulates the deposition orientation of Zn^(2+) and inhibits the formation of *** also reconstructs the solvation structure in the electrolyte to reduce water activity,enabling the electrolyte to have a lower freezing point for operation at low *** the assistance of Eryt,the Zn||Zn symmetric cell exhibits a long cycle life of 2000 h,while the ZIC assembled with activated carbon (AC) cathode and zinc anode (Zn||AC) maintains a capacity retention of 98.2% after 30,000 cycles at a current density of 10 A g^(-1)(even after 10,000 cycles at-20°C,the capacity retention rate reached 94.8%.).This work provides a highly scalable,low-cost and effective strategy for the protection of the anodes of low-temperature aqueous ZICs.

关键词： Zinc-ioncapacitors Electrolyte additive Dendrite-free Freeze-resistant electrolyte

Molecular rotaxane shuttle-relay accelerates K^(+)/Cl^(-) symport across a lipid membrane

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Science China Chemistry 2023年第8期66卷 2300-2308页

作者： Kai Ye zekai zhang Zexin Yan Shihao Pang Huiting Yang Xiaonan Sun Can Liu Linyong Zhu Cheng Lian Chunyan Bao Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering Feringa Nobel Prize Scientist Joint Research CenterFrontiers Science Center for Materiobiology and Dynamic ChemistryInstitute of Fine ChemicalsSchool of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai200237China State Key Laboratory of Bioreactor Engineering Shanghai Frontiers Science Center of Optogenetic Techniques for Cell MetabolismSchool of PharmacyEast China University of Science and TechnologyShanghai200237China

Synthetic molecules that can mediate the coupled transport of Cl^(-) with K^(+) and/or Na+across the lipid bilayers have aroused great interest due to their potential as a novel therapeutic strategy by disrupting cellular ion *** on the structural advantages of molecular rotaxanes,we herein show that two rotaxane-based transporters[2]R and[3]R induce coupled K^(+)/Cl^(-) channel transport by introducing Cl^(-) recognition sites in the thread and K^(+) binding group in the wheel,*** welldesigned molecular structures allow the insertion of unimolecular rotaxanes into the lipid bilayer,thus achieving effective ion transport by means of thermodynamically controlled movement and driven by the difference in ion concentration inside and outside the *** addition,the use of a three-component rotaxane can accelerate ion transport through a cooperative shuttlerelay mechanism in which two wheels move along the thread in the lipid membrane,thereby enabling[3]R to have higher ion transport *** work represents a major advance in the use of rotaxane molecules to accomplish more complex and effective tasks.

关键词： K^(+)/Cl^(-)symport molecular rotaxane artificial ion channel ion-pair recognition