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Acta Mechanica Sinica 2011年第6期27卷 1001-1012页

作者： tao he he-Ming Wen Xiao-Jun Guo CAS Key Laboratory for Mechanical Behavior and Design of Materials University of Science and Technology of China 230027 Hefei China

A dynamic spherical cavity-expansion penetration model is suggested herein to predict the penetration and perforation of concrete targets struck normally by ogivalnosed *** dilatancy as well as compressibility of the material in comminuted region are considered in the paper by introducing a dilatant-kinematic relation.A procedure is first presented to compute the radial stress at the cavity surface and then a numerical method is used to calculate the results of penetration and perforation with friction being taken into *** influences of various target parameters such as shear strength,bulk modulus,density,Poisson＇s ratio and tensile strength on the depth of penetration are *** is shown that the model predictions are in good agreement with available experimental *** is also shown that the shear strength plays a dominant role in the target resistance to penetration.

关键词： Spherical cavity expansion Shear dilatancy Ogival-nosed projectile Concrete target Penetration Perforation

An Empirical Method for Prediction of Hypersonic Rarefied Flow-Field Structure

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Transactions of Nanjing University of Aeronautics and Astronautics 2017年第5期34卷 543-552页

作者： he tao Wang Jiangfeng College of Aerospace Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016 P.R. China

Numerical simulations are presented about the effects of gas rarefaction on hypersonic flow *** to the extremely difficult experiment,limited wind-tunnel conditions and high cost,most problems in rarefied flow regime are investigated through numerical methods,in which the direct simulation Monte-Carlo(DSMC)method is widely *** the unstructured DSMC method is employed *** around a vertical plate at a given velocity 7 500 m/s are *** gas rarefaction is judged by the free-stream Knudsen number(Kn),two vital factors are considered:molecular number density and the plate′s *** in which Kn varies from 0.035 to13.36 are *** characters in the whole rarefied regime are described,and flow-field structure affected by Knis ***,the dimensionless position D*of a certain velocity in the stagnation line is chosen as the marker of flow field to measure its *** flow-field tracing and least-square numerical method analyzing,it is proved that hypersonic rarefied flow field expands outward linearly with the increase of 1/*** empirical method is proposed,which can be used for the prediction of the hypersonic flow-field structure at a given inflow velocity,especially the shock wave position.

关键词： hypersonic rarefied flow Kn direct simulation Monte-Carlo(DSMC)mothod linear expansion flowfield prediction

Simple colorimetric detection of dopamine using modified silver nanoparticles

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Science China Chemistry 2016年第4期59卷 387-393页

作者： Sivakumar Palanisamy Xuehua Zhang tao he Key Laboratory of Nanosystem and Hierarchical Fabrication Chinese Academy of SciencesNational Center for Nanoscience and TechnologyBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Dopamine(DA) plays an important role in health and peripheral nervous systems. Colorimetric detection of DA has the advantage of color change and simplicity in operation and instrumentation. herein, we report a highly sensitive and selective colorimetric detection of DA by using two specific ligands modified Ag nanoparticles, where the DA molecules can make dual recognition with high specificity. The colloidal suspension of modified Ag nanoparticles was agglomerated after interacting with DA, while the color of Ag nanoparticles suspension changed from yellow to brown, arising from the interparticle plasmon coupling during the aggregation of Ag nanoparticles. The modified Ag nanoparticles suspension and agglomeration were confirmed by transmission electron microscope images. The optical properties behind the color change were thoroughly investigated by using UV-Vis and Raman techniques. The changes in p H, zeta potential, particle size and surface charge density by adding DA were also determined by using dynamic light scattering measurements. The detection limits of modified Ag probes for DA was calculated to be 6.13′10^(-6) mol L^(-1)(S/N=2.04) and the correlation co-efficient was determined to be 0.9878. Because of the simplicity in operation and instrumentation of the colorimetric method, this work may afford a feasible, fast approach for detecting and monitoring the DA levels in physiological and pathological systems.

关键词： dopamine detection Ag nanoprobe colorimetry dual molecular recognition sensitivity selectivity

Fast M-fold matching pursuit algorithm for image approximation

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Journal of Systems Engineering and Electronics 2009年第4期20卷 883-888页

作者： Gan tao he Yanmin Zhu Weile School of Electronic Engineering Univ. of Electronic Science and Technology of China Chengdu 610054 P. R. China.

A simple and effective greedy algorithm for image approximation is proposed. Based on the matching pursuit approach, it is characterized by a reduced computational complexity benefiting from two major modifications. First, it iteratively finds an approximation by selecting M atoms instead of one at a time. Second, the inner product computations are confined within only a fraction of dictionary atoms at each iteration. The modifications are implemented very efficiently due to the spatial incoherence of the dictionary. Experimental results show that compared with full search matching pursuit, the proposed algorithm achieves a speed-up gain of 14.4-36.7 times while maintaining the approximation quality.

关键词： greedy algorithm image approximation matching pursuit

Rotational properties of the odd-Z transfermium nucleus ^(255)Lr by a particle-number-conserving method in the cranked shell model

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Science China(Physics,Mechanics & Astronomy) 2016年第7期59卷 25-32页

作者： Yu-Chun Li Xiao-tao he College of Material Science and Technology Nanjing University of Aeronautics and Astronautics Nanjing 210016 China

Experimentally observed ground state band based on the 1/2-[521] Nilsson state and the first exited band based on the 7/2-[514] Nilsson state of the odd-Z nucleus 255Lr are studied by the cranked shell model （CSM） with the paring correlations treated by the particle-number-conserving （PNC） method. This is the first time the detailed theoretical investigations are performed on these rotational bands. Both experimental kinematic and dynamic moments of inertia （f^（1） and ,f^（2） versus rotational frequency are reproduced quite well by the PNC-CSM calculations. By comparing the theoretical kinematic moment of inertia f（1） with the experimental ones extracted from different spin assignments, the spin 17/2- →13/2- is assigned to the lowest-lying 196.6（5） keV transition of the 1/2- [521 ] band, and 15/2→11/2- to the 189（1） keV transition of the 7/2- [514] band, respectively. The proton N = 7 major shell is included in the calculations. The intruder of the high-j low→lj15/2 （1/2-[770]） orbital at the high spin leads to band-crossings at hω = 0.20 （hω~=0.25） MeV for the 7/2-[514]ω= -1/2 （ω= ＋1/2） band, and at hω=0.175 MeV for the 1/2- [521 ] ω= - 1/2 band, respectively. Further investigations show that the band-crossing frequencies are quadrupole deformation dependent.

关键词： rotational band spin assignment band-crossing high-j orbital transfermium nuclei

High performance scalable image coding

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Journal of Systems Engineering and Electronics 2007年第4期18卷 795-800页

作者： Gan tao he Yanmin Zhu Weile chool of Electronic Engineering Univ. of Electronic Science and Technology of China Chengdu 610054 P. R. China

A high performance scalable image coding algorithm is proposed. The salient features of this algorithm are the ways to form and locate the significant clusters. Thanks to the list structure, the new coding algorithm achieves fine fractional bit-plane coding with negligible additional complexity. Experiments show that it performs comparably or better than the state-of-the-art coders. Furthermore, the flexible codec supports both quality and resolution scalability, which is very attractive in many network applications.

关键词： scalable image coding significant clusters list structure

Silicon isotope fractionation during the precipitation of quartz and the adsorption of H_4SiO_(4(aq))on Fe(Ⅲ)-oxyhydroxide surfaces

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Chinese Journal Of Geochemistry 2015年第4期34卷 459-468页

作者： Hong-tao he Yun Liu State Key Laboratory of Ore Deposit Geochemistry Institute of Geochemistry Chinese Academy of Sciences University of Chinese Academy of Sciences

Equilibrium Si isotope fractionation factors among orthosilicic acid(i.e.,H4 Si O4(aq)), quartz and the adsorption complexes of H4 Si O4(aq)on Fe(III)-oxyhydroxide surface were calculated using the full-electron wave-function quantum chemistry methods [i.e., B3LYP/6-311G(2df,p)]with a new cluster-model-based treatment. Solvation effects were carefully included in our calculations via water-droplet method combined with implicit solvent models(e.g., PCM).The results revealed that, if it is under equilibrium conditions,heavy Si isotopes would be significantly enriched in quartz in comparison to H4 Si O4(aq). However, most of the field observations suggested that quartz would have identical or even depleted d30 Si values compared to that of H4 Si O4(aq). To explain this discrepancy between the equilibrium calculation results and the field observations, the kinetic isotope effect(KIE) associated with the formation of amorphous silica,which usually is the precursor of crystalline quartz, was investigated using quantum chemistry methods. The KIE results showed that amorphous silica would be significantly enriched in light Si isotopes during its formation. Our equilibrium fractionation results, however, matched a special type of quartz(i.e., herkimer ‘‘diamond'') very well, due to its nearly equilibrated precipitation condition. Opposite to the case of precipitated quartz, a large equilibrium Si isotope fractionation(i.e.,-3.0 %) was found between the absorbed bidentate Si surface complexes(i.e.,2C [ Fe2O2Si(OH)2) and H4 Si O4(aq). This calculated equilibrium Si isotope fractionation factor largely differed from a previous experimental result(ca.-1.08 %). We found that the formation of transient or temporary surface complexes [e.g.,1V [ Fe2OSi(OH)3] may have accounted for the smaller net fractionation *** the equilibrium and kinetic Si isotope fractionation factors provided here, the distributions and changes of Si isotope compositions in the Earth's surface syste

关键词：同位素分馏 Fe(Ⅲ) 沉淀条件硅表面石英硅酸吸附过程量子化学计算方法

Catalytic asymmetric synthesis of 1,4-enynes

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Chinese Chemical Letters 2023年第8期34卷 18-27页

作者： Han-Yu Lu Zhi-tao he CAS Key Laboratory of Synthetic Chemistry of Natural Substances Shanghai Institute of Organic ChemistryUniversity of Chinese Academy of SciencesShanghai 200032China School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210China School of Chemistry and Materials Science Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China

1,4-Enyne units are ubiquitous skeletons in biologically active molecules and natural ***,they represent versatile building blocks for abundant downstream derivatizations via controllable modifications of both alkene and alkyne units ***,great efforts have been made to establish efficient protocols to achieve optically active 1,*** the enormous application potential of enantioenriched 1,4-enyne units but no related review on this topic has been described,here we aim to provide a comprehensive summary on the catalytic methods established for enantioselective constructions of these intriguing *** to the reaction types,this review is divided into five parts,including asymmetric allylic substitution,asymmetric propargylic substitution,asymmetric alkynylallylic substitution,asymmetric hydroalkynylation and asymmetric 1,2-addition of alkynes to conjugated imines or ketones.

关键词： 1,4-Enynes Catalytic reaction Asymmetric synthesis

Research Progress on the Electrical Properties of Gas Hydrate-bearing Sediments

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Acta Geologica Sinica(English Edition) 2023年第3期97卷 816-827页

作者： TAN Kui ZHANG Qi he tao Key Laboratory of Orogenic Belts and Crustal Evolution(Ministry of Education) School of Earth and Space SciencesPeking UniversityBeijing 100871China Beijing International Center for Gas Hydrate Peking UniversityBeijing 100871China

Electrical properties are important physical parameters of natural gas hydrate,and,specifically,resistivity has been widely used in the quantitative estimation of hydrate *** are three main methods to study the electrical properties of gas hydrate-bearing sediments:experimental laboratory measurements,numerical simulation,and resistivity *** measurements can be divided into three categories:normal electrical measurement,complex resistivity measurement,and electrical resistivity *** measurements show that the resistivity of hydrate-bearing sediment is affected by many factors,and its distribution as well as the hydrate saturation is not uniform;there is a distinct non-Archie *** numerical method can simulate the resistivity of sediments by changing the hydrate occurrence state,saturation,distribution,***,it needs to be combined with X-ray CT,nuclear magnetic resonance,and other imaging techniques to characterize the porous characteristics of the hydrate-bearing *** well logging can easily identify hydrate layers based on their significantly higher resistivity than the background,but the field data of the hydrate layer also has a serious non-Archie ***,more experimental measurements and numerical simulation studies are needed to correct the parameters of Archie’s formula.

关键词： resource exploration gas hydrate resistivity hydrate saturation numerical simulation well logging Archie's formula

C-di-GMP signaling and implications for pathogenesis of Mycobacterium tuberculosis

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Chinese Science Bulletin 2012年第34期57卷 4387-4393页

作者： CUI tao he ZhengGuo National Key Laboratory o.f Agricultural Microbiology Center for Proteomics Research College of Life Science and Technology HuazhongAgricultural University Wuhan 430070 China

C-di-GMP is a ubiquitous bacterial second messenger that regulates a wide range of bacterial physiological processes including biofilm formation, virulence, motility and cell differentiation. here, we have summarized our current knowledge on the upstream signaling factors and downstream effectors of c-di-GMP in addition to the interaction between c-di-GMP and eukaryotic organisms. New discoveries in these areas have enriched our understanding of the diversity of c-di-GMP signaling pathways and provide important clues for us to explore the roles of c-di-GMP signaling in human pathogens such as Mycobacterium tuberculosis.

关键词：结核病细菌生物膜发病信令信号通路结核分枝杆菌第二信使生理过程