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Transition metal-doped heteropoly catalysts for the selective oxidation of methacrolein to methacrylic acid

Frontiers of Chemical Science and engineering 2016年第1期10卷 139-146页

作者： Yanxia Zheng Heng Zhang Lei Wang Suojiang Zhang Shaojun Wang School of Light Industry and Chemical engineering Dalian Polytechnic University Dalian 116034 China Beijing key laboratory of Ionic Liquids Clean Process Key Laboratory of Green Process and Engineering State Key Laboratory of Multiphase Complex Systems Institute of Process Engineering Chinese Academy of Sciences Beijing 100190 China School of Chemistry and Chemical engineering Qufu Normal University Qufu 273165 China

Heteropoly compounds with the general formula Cs1Mo.5X＋H3-o.5xP1.2MOllVO4o （M = Fe, Co, Ni, Cu or Zn） and CslCuyH3_2yP1.2MO11VO40 （y = 0.1, 0.3 or 0.7） were synthesized and then used as catalysts for the selective oxidation of methacrolein to methacrylic acid. The effects of the transition metals on the structure and activity of the catalysts were investigated. FTIR spectra showed that the transition metal-doped catalysts main- tained the Keggin structure of the undoped catalysts. X-ray diffraction results indicated that before calcination, the catalysts doped with Fe and Cu had cubic secondary structures, while the catalysts doped with Co, Ni or Zn had both triclinic and cubic phases and the Co-doped catalyst had the highest content of the triclinic form. Thermal treatment can decrease the content of the triclinic phase. NH3 temperature-programmed desorption and H2 tem- perature-programmed reduction results showed that the transition metals changed the acid and redox properties of the catalysts. The addition of Fe or Cu had positive effects on the activities of the catalyst which is due to the improvement of the electron transfer between the Fe or Cu and the Mo. The effects of the copper content on structure and catalytic activity were also investigated. The CSlCUo.3H2P1.2MO11VO40 catalyst had the best performance for the selective oxidation of methacrolein to methacrylic acid.

关键词： heteropoly compounds transition metals selective oxidation methacrolein

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Equivalent pipe algorithm for metal spiral casing and its application in hydraulic transient computation based on equiangular spiral model

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Journal of Hydrodynamics 2014年第1期26卷 137-143页

作者：彭小东杨朝晖刘善均鞠小明 State key laboratory of Hydraulics and Mountain River engineering Sichuan University Department of Water Resources of Guizhou Province

For the metal spiral casing of water turbines, a new equivalent pipe algorithm is developed based on the idea of equiangu-lar spiral. Prototype tests and computations are carried out to investigate the hydraulic transient characteristics. The computation re-sults by using the new model are in a good agreement with the prototype test data with respect to the maximum speed of the tur-bine-generator unit, the maximum water hammer pressure in the spiral casing and the maximum vacuum in the draft tube. The propo-sed method is a significant improvement over the conventional algorithm with the accuracy increased and the error reduced by about 3%.

关键词： equiangular spiral metal spiral casing equivalent pipe hydraulic transient

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Fabrication of low-resistance LaNi_xO_(3+δ) thin films for ferroelectric device electrodes

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Journal of Rare Earths 2018年第8期36卷 838-843页

作者： Mi Xiao Zebin Zhang Weikang Zhang Ping Zhang Kuibo Lan School of Electrical and Information engineering & key laboratory of Advanced Ceramics and Machining Technology of Ministry of Education Tianjin University

LaNiO3 thin films with different La/Ni ratios were deposited on Si substrates by sol-gel process. The electrical resistivities of LaNixO3＋δfilms with different La/Ni ratios were measured by four-probe ***（0.95）O3＋δthin film has the lowest resistivity. First-principle calculations show that LaNi（0.95）O3＋δhas the largest Ni-O-Ni bond angle and the shortest Ni-O bond length, which means LaNi（0.95）O3＋δhas the strongest metallic property, hence, the electrical resistivity is the lowest. Au/PZT（PbZr（0.52）Ti（0.48）O3）/LaNixO3＋δand Au/PZT/Pt ferroelectric capacitors were fabricated to evaluate LaNixO3＋δas a bottom electrode. It is shown that fatigue properties of PZT films can be significantly improved by using LaNixO3＋δinstead of Pt as the bottom electrode. The Ⅰ-Ⅴ test results of PZT films show that LaNi（0.95）O3＋δas bottom electrode can reduce the threshold voltages of PZT films, suggesting that La/Ni ratio in LaNixO3＋δas a large influence on the film properties.

关键词： LaNiO3 Thin film Sol-gel Electrical property First-principle calculation Rare earths

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Unusual one-way edge state in acoustic gyroscopic continuum

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Science China(Physics,Mechanics & Astronomy) 2019年第1期62卷 76-82页

作者： XiaoMing Zhou YuChen Zhao key laboratory of Dynamics and Control of Flight Vehicle Ministry of Education and School of Aerospace Engineering Beijing Institute of Technology

Unusual one-way edge states have been observed in composite structures composed of periodic lattices loaded with ***, we provide a continuum-mechanics understanding to the one-way edge state by formulating surface state equations of acoustic gyroscopic mediums with Hermite mass density tensor. We discover that the unidirectional edge effect arises from nontrivial off-diagonal components of Hermite densities, which causes the symmetric breaking of surface wave propagation towards forward and backward directions. Theoretical predictions on the velocity and decay length of surface waves coincide excellently with numerical simulations. The unidirectional edge state in a two-interface gyroscopic medium is also *** to the rotational symmetry in geometry, the unidirectional edge state on one interface is able to prevent itself from the coupling to surface waves on the other interface regardless of the slab thickness. With these anomalous effects, surface waves residing on gyroscopic mediums can flow around the edge defects without back-scatterings, or can be split into two beams of equal energy magnitudes. Our findings may make a bridge that would help to reach the design of non-reciprocal composite materials via an effective medium approach.

关键词： gyroscopic medium one-way edge state quantum Hall effect

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Catalyst-free multicomponent polymerization of sulfonyl azide,aldehyde and cyclic amino acids toward zwitterionic and amphiphilic poly(N-sulfonyl amidine)as nanocatalyst precursor

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Science China Chemistry 2022年第9期65卷 1798-1806页

作者： Erli Tian Ming Li Wangze Song Nan Zheng State key laboratory of Fine Chemicals School of Chemical EngineeringDalian University of TechnologyDalian 116024China

Polymers with metal coordination ability are outstanding precursors of nanocatalysts,attracting numerous attention in nanocatalysis *** has been rarely reported for the poly(N-sulfonyl amidines)as macromolecular ligands for ***,a catalyst-free multicomponent polymerization(MCP)strategy is developed to facilely prepare a library of amphiphilic poly(Nsulfonyl amidines)with zwitterionic properties starting from disulfonyl azide,hydrophilic dialdehyde and cyclic amino acids including proline and pipecolinic *** or additives can be thorougly avoided through this *** the obtained polymers have well-defined structures,high yields and weight-average molecular weights(M_(w)s,up to 99,300 g/mol).The unique zwitterionic property,amphiphilicity and Cu(Ⅰ)coordination ability of the obtained poly(N-sulfonyl amidines)endow them to form the polymer-Cu(Ⅰ)complexes as *** nanocatalysts exhibit high catalytic efficiency in aqueous Cucatalyzed azide-alkyne cycloaddition(CuAAC)reaction at a low Cu(Ⅰ)loading of 50 *** with a high ratio of polymers to Cu(Ⅰ)have also been demonstrated with Cu(Ⅰ)stabilization *** work provides a“green”MCP method toward zwitterionic and amphiphilic poly(N-sulfonyl amidines),and highlights their unique potentials for nanocatalysis.

关键词： multicomponent polymerization zwitterion catalyst-free nanocatalysis poly(N-sulfonyl amidines)

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TOPOLOGICAL STRUCTURES OF VORTEX AND HELICITY ANALYSIS

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Acta Mechanica Sinica 1998年第3期14卷 208-214页

作者：黄永念苏卫东 State key laboratory for Turbulence Research Department of Mechanics and Engineering SciencePeking UniversityBeijing 100871China

The topological structures of the vortex filaments and vortex tubes with an exact solution of a straight spiral vortex tube are discussed. It is found that there are some confusions about the calculation of the helicity of a knotted vortex filament and some linked vortex filaments by using different methods. How to unify these methods is explained and the right results are given. (Edited author abstract) 5 Refs.

关键词： topological structure vortex filament helicity knot and link

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Multiscale frictional behaviors of sp^(2) nanocrystallited carbon films with different ion irradiation densities

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Friction 2021年第5期9卷 1025-1037页

作者： Zelong HU Xue FAN Cheng CHEN Institute of Nanosurface Science and engineering Guangdong Provincial Key Laboratory of Micro/Nano Optomechatronics EngineeringCollege of Mechatronics and Control EngineeringShenzhen UniversityShenzhen 518060China

sp^(2) nanocrystallited carbon films with large nanocrystallite sizes,smooth surfaces,and relative high hardness were prepared with different ion irradiation densities regulated with the substrate magnetic coil current in an electron cyclotron resonance plasma sputtering *** multiscale frictional behaviors were investigated with macro pin‐on‐disk tribo‐tests and micro nanoscratch *** results revealed that,at an ion irradiation density of 16 mA/cm^(2),sp^(2) nanocrystallited carbon film exhibits the lowest friction coefficient and good wear resistant properties at both the macroscale and *** film sliding against a Si_(3)N_(4) ball under a contact pressure of 0.57 GPa exhibited a low friction coefficient of 0.09 and a long wear life at the ***,the film sliding against a diamond tip under a contact pressure of 4.9 GPa exhibited a stable low friction coefficient of 0.08 with a shallow scratch depth at the *** is suggested that sp^(2) nanocrystallites affect the frictional behaviors in the cases described *** the macroscale,the contact interface via the small real contact area and the sp^(2) nanocrystallited transfer layer dominated the frictional behavior,while the sp^(2) nanocrystallited structure in the film with low shear strength and high plastic resistivity,as well as the smooth surface morphology,decided the steady low nanoscratch properties at the *** findings expand multiscale tribological applications of sp^(2) nanocrystallited carbon films.

关键词： macro‐tribology micro‐tribology sp^(2)nanocrystallite carbon film ion irradiation density

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Spatiotemporal sectioning of two-photon fluorescence ellipsoid with a CsPbBr_(3) nanosheet

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Nano Research 2021年第11期14卷 4288-4293页

作者： Yizhi Zhu Jinping Chen Qiannan Cui Heng Guo Zhuxin Li Zengliang Shi Chunxiang Xu State key laboratory of Bioelectronics School of Biological Science and Medical EngineeringSoutheast UniversityNanjing210096China

Two-photon fluorescence (TPF) ellipsoid formed by a focused femtosecond laser into luminescent media serves as a fundamental pixel for TPF spatiotemporal imaging. Visualizing spatiotemporal evolution of the TPF ellipsoid itself in a selected luminescent medium is important for correctly reconstructing and interpreting spatiotemporal information of imaged targets. Here, we report a new spatiotemporal sectioning technique with a luminescent CsPbBr_(3) nanosheet and visualize the spatiotemporal evolution of TPF ellipsoid along the axial direction. Time-resolved axial lengths of TPF ellipsoids turn out to broaden nonlinearly with a turning point at about 600 ps. By comparison experiments, observed phenomena are attributed to photocarrier trapping and TPF photon recycling processes within CsPbBr_(3) nanosheets. The spatiotemporal sectioning technique is expected to be widely applicable, which will ignite a plethora of investigations and applications utilizing TPF ellipsoid.

关键词： spatiotemporal sectioning two-photon fluorescence ellipsoid CsPbBr_(3)nanosheet photocarrier trapping photon recycling

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Strain engineering of Pt-based electrocatalysts for oxygen reaction reduction

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Frontiers in Energy 2024年第2期18卷 241-262页

作者： Zeyu WANG Yanru LIU Shun CHEN Yun ZHENG Xiaogang FU Yan ZHANG Wanglei WANG State key laboratory of Solidification Processing Atomic Control and Catalysis Engineering LaboratorySchool of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China State key laboratory of Oral and Maxillofacial Reconstruction and Regeneration National Clinical Research Center for Oral DiseasesShaanxi Key Laboratory of StomatologyDepartment of Dental MaterialsSchool of StomatologyThe Fourth Military Medical UniversityXi’an 710032China Institute of New Energy Materials and engineering School of Materials Science and EngineeringFuzhou UniversityFuzhou 350108China key laboratory of Marine Chemistry Theory and Technology(Ministry of Education) College of Chemistry and Chemical EngineeringOcean University of ChinaQingdao 266100China

Proton exchange membrane fuel cells(PEMFCs)are playing irreplaceable roles in the construction of the future sustainable energy ***,the insufficient performance of platinum(Pt)-based electrocatalysts for oxygen reduction reaction(ORR)hinders the overall efficiency of *** the surface strain of catalysts is considered an effective way to tune their electronic structures and therefore optimize catalytic *** this paper,insights into strain engineering for improving Pt-based catalysts toward ORR are elaborated in ***,recent advances in understanding the strain effects on ORR catalysts are comprehensively ***,strain engineering methodologies for adjusting Ptbased catalysts are comprehensively ***,further information on the various challenges and potential prospects for strain modulation of Pt-based catalysts is provided.

关键词： strain engineering Pt-based catalysts oxygen reduction reaction(ORR) catalytic performance proton exchange membrane fuel cells(PEMFCs)

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The heat transfer optimization of conical fin by shape modification

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Chinese Journal of Chemical engineering 2016年第8期24卷 972-978页

作者： Jiansheng Wang Xiao Wang key laboratory of Efficient Utilization of Low and Medium Grade Energy MOE School of Mechanical Engineering Tianjin University

In present work, a stepping optimization algorithm is proposed for the geometric optimization of conical fin, and the heat transfer rate of the fin is treated as the objective function in the optimization algorithm. The conical fin is divided into finite elements which have different generatrix slopes, and the geometry of the conical fin is finally determined by ensuring that every divided element can maintain the maximum heat transfer rate. Based on the actual condition of every element of the fin, the heat conduction equation is solved step by step. The present result shows that the optimized conical fin has more heat transfer quantity and higher fin efficiency compared with those of some typical fins. Furthermore, the theoretical feasibility and the error analysis of present optimization algorithm have been performed as well.

关键词： Fin Optimization Heat transfer Stepping optimization algorithm

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