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Density functional study on the bimetallic Ti_mZr_n(n+m ≤ 5) clusters and their interactions with H_2

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Chinese Physics B 2018年第9期27卷 262-269页

作者： ge zhang Yong Sheng College of Materials Science and Engineering Sichuan UniversityChengdu 610065China

Equilibrium geometries, stabilities, and electronic properties of small TimZrn（n ＋ m ≤ 5） clusters were investigated using the density functional method. The ground states were determined, and it was found that the larger clusters and those consisting of more Zr atoms are more stable. The electronic properties of the clusters were discussed based on HOMO-LUMO gaps, vertical ionization potentials（VIP）, and vertical electron affinities（VEA）. Furthermore, we studied the interactions between those clusters and molecular hydrogen, and found that in all the cases dissociative chemisorptions occurred. According to the chemisorption energies, the pure Zr clusters are relatively more active towards H2 when compared with the others except Ti3Zr, which shows the highest activity. The magnetic moments of TimZrn and TimZrnH2 were also compared, and the results show that the hydrogenated clusters have the same or decreased total magnetic moments with respect to the bare clusters except for Ti3Zr2.

关键词： density functional theory bimetallic cluster hydrogen chemisorption

Energy estimation and coupling synchronization between biophysical neurons

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Science China(Technological Sciences) 2020年第4期63卷 625-636页

作者： WU FuQiang MA Jun zhang ge Department of Physics Lanzhou University of TechnologyLanzhou 730050China NAAM-Research Group King Abdulaziz UniversityJeddah 21589Saudi Arabia

Static charges can induce spatial electric field while moving charges can induce magnetic *** a result,continuous pumping and exchange of intercellular and extracellular Calcium,potassium and sodium of cells will generate time-varying magnetic field in the ***,the physical effect of electromagnetic induction in neural activities should be included in building biological *** the other hand,the occurrence of action potential and propagation of ions require energy consumption and supply,so the estimation of physical energy becomes *** on our memristive biophysical neuron model,the Hamilton energy function is obtained by using the Helmholtz’s theorem,and this energy is contributed by the electric field and magnetic field described by magnetic *** is found that this improved neuron model can present the main dynamical properties in neural activities,and it characterizes the lower threshold behavior and subthreshold oscillation during refractory *** external forcing current on an isolate is adjusted to calculate the firing patterns,energy function and mode transition,which shows the dependence of energy on electrical ***,magnetic coupling is triggered to modulate the phase synchronization between two identical neurons connected by electric synapse,respectively.

关键词： memristor energy magnetic field phase synchronization

Alignment between satellite and central galaxies in the EAGLE simulation:dependence on the large-scale environments

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Research in Astronomy and Astrophysics 2019年第12期19卷 287-297页

作者： Ming-ge zhang Yang Wang School of Physics and Astronomy Sun Yat-sen University

The alignment between satellite and central galaxies serves as a proxy for addressing the issue of galaxy formation and evolution, and has been investigated abundantly in observations and theoretical *** scenarios indicate that the satellites preferentially are located along the major axis of their central galaxy. Recent work shows that the strength of alignment signals depends on the large-scale environment in observations. We use the publicly-released data from EAGLE to figure out whether the same effect can be found in the associated hydrodynamic simulation. We found much stronger environmental dependency of alignment signals in the simulation. We also explore change of alignments to address the formation of this effect.

关键词： methods:statistical methods:theoretical galaxies:evolution galaxies:general cosmology:large-scale structure of Universe

N-doped carbon nanotube encapsulated nZVI as a high-performance bifunctional catalyst for oxidative desulfurization

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Particuology 2023年第10期81卷 109-118页

作者： ge zhang Fan Yang Wang Yang Yongfeng Li State Key Laboratory of Heavy Oil Processing China University of PetroleumBeijingChina Beijing NAURA Vacuum Technology Co. LtdBeijingChina

Great efforts have been made to remove sulfur from fossil fuels to protect the *** proposed synthesis of high efficiency oxidation desulfurization(ODS)catalysts by encapsulating nano zero valent iron(nZVI)in self-catalyzed carbon *** synthetic strategy features facile hydrothermal and pyrolysis *** specific surface area,pore structure,and microstructure of the catalysts were characterized by series techniques,and the catalytic ability was evaluated by the reduction of sulfur after oxidation and *** optimized nZVI@CNT catalyst exhibits outstanding catalytic performance(within 120 min,the oxidative removal rate of DBT reached 96%)and enhanced stability(a 80%retention of initial performance after six cycles.),revealing the effective optimization and modulation between carbon nanotubes and iron *** excellent ODS activity originated from the defects of N-doped nanotubes as well as excellent particle dispersion and material transport capacity,which excites highly active free radicals with the assistance of H_(2)O_(2).In addition,the unique two-dimensional tube channel and mesoporous structure promoted the diffusion and transfer of reactants and electrons,leading to high density of active *** different experimental conditions confirmed that the material is a bifunctional catalyst integrating adsorption and *** work provides an creative ideas for the rational design and synthesis of advanced ODS catalysts for fuel oil.

关键词： Carbon nanotubes Oxidative desulfurization Dispersion Nanoscale zero valent iron

Cobalt(Ⅲ)hydride HAT mediated enantioselective intramolecular hydroamination access to chiral pyrrolidines

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Science China Chemistry 2024年第6期67卷 2002-2008页

作者： Qi Meng Tao Qin Huanran Miao ge zhang Qian zhang Jilin Province Key Laboratory of Organic Functional Molecular Design&Synthesis Department of ChemistryNortheast Normal UniversityChangchun130024China State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai200032China

Enantioenriched pyrrolidines and derivatives are ubiquitous substructures in compounds of importance to medicinal and biological ***,we report an efficient cobalt-catalyzed intramolecular asymmetric hydroamination reaction that produces chiral pyrrolidines with good to excellent yield and *** with previously reported radicalinvolved methodologies for enantioenriched pyrrolidines,these conditions feature two elegant versatilities,enabling(1)the use of cobalt-catalyzed hydrogen atom transfer(HAT)to generate organocobalt intermediates that bring radical reaction to organometallic chemistry,and(2)enantioselective intramolecular C-N bond forging through an S_(N)2-like displacement involving dynamic kinetic resolution(DKR).This approach provides a new alternative and efficient methodology for enantioselective radical-involved C-N bond construction that can be used in the synthesis of both chiral pyrrolidines and homologous nitrogen heterocycles.

关键词： asymmetric catalysis radical hydroamination cobalt catalysis hydrogen atom transfer

Radical cascade reactions of unsaturated C–C bonds involving migration

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Science China Chemistry 2019年第11期62卷 1476-1491页

作者： ge zhang Yang Liu Jinbo Zhao Yan Li Qian zhang Jilin Province Key Laboratory of Organic Functional Molecular Design&Synthesis Department of ChemistryNortheast Normal UniversityJilin 130024China State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China

During the past few years, with the rapid development of mild methods for the generation of radical species, great progress in radical cascade reactions of unsaturated C–C bonds has been made. Many radical cascade reactions involve functional groups migration, which leads structurally much more diverse, complex and valuable compounds not easily obtained through other methods. In this review, the recent achievements in unsaturated C–C bonds radical cascade reactions involving migration are summarized.

关键词： radical cascade reaction functional group migration unsaturated C–C bonds C-centered radicals N-centered radicals

Cardiac tissue-derived extracellular matrix scaffolds for myocardial repair:advantages and challenges

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Regenerative Biomaterials 2019年第4期6卷 185-199页

作者： Pawan KC Yi Hong ge zhang Department of Biomedical Engineering The University of AkronOlson Research CenterRoom 301L260 S Forge StreetAkronOH 44325USA Department of Bioengineering University of Texas at Arlington500 UTA BlvdRoom 240ArlingtonTX 76019USA

Decellularized extracellular matrix(dECM)derived from myocardium has been widely explored as a nature scaffold for cardiac tissue engineering *** dECM offers many unique advantages such as preservation of organ-specific ECM microstructure and composition,demonstration of tissue-mimetic mechanical properties and retention of biochemical cues in favor of subsequent ***,current processes of dECM decellularization and recellularization still face many challenges including the need for balance between cell removal and extracellular matrix preservation,efficient recellularization of dECM for obtaining homogenous cell distribution,tailoring material properties of dECM for enhancing bioactivity and prevascularization of thick *** review summarizes the recent progresses of using dECM scaffold for cardiac repair and discusses its major advantages and challenges for producing biomimetic cardiac patch.

关键词： myocardial infarction decellularized extracellular matrix scaffold cardiac tissue engineering

Electron beam surface heating-diffusion bonding:An effective joining method for aluminum alloy metal-matrix composite with high SiC volume

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Journal of Materials Science & Technology 2021年第29期88卷 109-118页

作者： Guoqing Chen Qianxing Yin Jian Cao ge zhang Gongbo Zhen Binggang zhang State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin150001China

As a novel method to reduce the temperature during electron beam welding,and to subsequently inhibit interfacial reaction between SiC and Al matrix,the electron beam surface heating-diffusion bonding is proposed for joining SiC particle reinforced aluminum alloy metal-matrix composite of 45 vol.%SiC/2024 *** defocused electron beam was used to heat the base metal surface,and the simultaneous pressure was applied to the butt surface to achieve *** base metals were successfully joined by *** maximum temperature of the whole joint was effectively decreased to less than 650°*** Gibbs free energy change of interfacial reaction was calculated,meaning a positive value reaching 218 kJ/mol and a consequently prominent inhibitory effect on the formation of brittle Al_(4)C_(3)that was proved by microstructural *** tensile strength for the bonded joint was increased by 35%compared to that for ordinary welded *** the TC4 layer was added,TiC strengthening particles were formed with the deficiency of Al_(4)C_(3),corresponding to the significantly increased tensile strength of 63%of base metal(154 MPa).

关键词： 45 vol.%SiC/2024 Al Electron beam surface heating-diffusion bonding Interfacial reaction inhibition Gibbs free energy change

Rayleigh-Taylor instability under multimode perturbation:Discrete Boltzmann modeling with tracers

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Communications in Theoretical Physics 2022年第11期74卷 180-198页

作者： Hanwei Li Aiguo Xu ge zhang Yiming Shan Laboratory of Computational Physics Institute of Applied Physics and Computational MathematicsBeijing 100088China HEDPS Center for Applied Physics and TechnologyCollege of EngineeringPeking UniversityBeijing 100871China State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China Energy Resources Engineering Department Stanford University367 Panama StStanfordCA 94305-2220United States of America

The two-dimensional Rayleigh-Taylor Instability(RTI)under multi-mode perturbation in compressible flow is probed via the Discrete Boltzmann Modeling(DBM)with *** distribution of tracers provides clear boundaries between light and heavy fluids in the position ***,the position-velocity phase space offers a new perspective for understanding the flow behavior of RTI with intuitive geometrical *** effects of viscosity,acceleration,compressibility,and Atwood number on the mixing of material and momentum and the mean nonequilibrium strength at the interfaces are investigated separately based on both the mixedness defined by the tracers and the non-equilibrium strength defined by the *** mixedness increases with viscosity during early stage but decreases with viscosity at the later ***,compressibility,and Atwood number show enhancement effects on mixing based on different *** the system relaxes from the initial state,the mean non-equilibrium strength at the interfaces presents an initially increasing and then declining trend,which is jointly determined by the interface length and the macroscopic physical quantity *** conclude that the four factors investigated all significantly affect early evolution behavior of an RTI system,such as the competition between interface length and macroscopic physical quantity *** results contribute to the understanding of the multi-mode RTI evolutionary mechanism and the accompanied kinetic effects.

关键词： Rayleigh-Taylor instability multi-mode perturbation Discrete Boltzmann modeling tracers non-equilibrium effects kinetic modeling