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Oxygen isotopic (^(17)O-^(18)O) heterogeneity in Archaean continental nucleus, north china Craton

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chinese Science Bulletin 1999年第24期44卷 2267-2269页

作者： liu jianzhong, ZHAnG Fuqin, li chunlai and WAnG Shijie {3. of geochemistry ,{3. , Guiyang 550002 , china {3. of Geophysics ,{3. , Beijing 100101 , china institute of geochemistry Chinese Academy of Sciences Guiyang China institute of Geophysics Chinese Academy of Sciences Beijing China

The oxygen isotopic data for amphibolites from Archaean continental nucleus, north china Craton indicate that ( i ) the evolving lines structured by the data are parallel to the geoselenic evolving line, which means that the parent materials of these continental nucleus o-riginated from solar matter; ( ii ) different intercepts for these evolving lines manifest that oxy-

关键词： north china Craton oxygen isotope (I7O-18O ) heterogeneity.

Regulation mechanism of EM parameters in natural ferrite and its application in microwave absorbing materials

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Science china(Technological sciences) 2006年第1期49卷 38-49页

作者： ZHEnG Yongchun1,2, WAnG Shijie2, FEnG junming2, li chunlai1, OUYAnG Ziyuan1,2, liu jianzhong1 & li Xiaobiao2 1. national Astronomical Observatories, chinese academy of sciences, Beijing 100012, china 2. State Key Laboratory of Environmental {3., institute of {3., chinese academy of sciences, Guiyang 550002, china national Astronomical Observatories Chinese Academy of Sciences Beijing China State Key Laboratory of Environmental geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang China

Electromagnetic (EM) parameters (ε ′, ε ″, μ ′, μ″ ) of several M2+Fe2O4 and Fe2O3.type natural ferrites with different geological occurrences are measured in this pa-per. The measurement results show that EM parameters of a magmatic-occurring natural ferrite is very different from other types occurring from sedimentary-metamorphic iron deposit, hydrothermal vein iron deposit, outer contact of magmatic iron deposit. It has potential to be used as magnetic absorbent in microwave absorbing materials. After min-eral separation and concentration, this magmatic-occurring natural ferrite was processed into type A ferrite absorbent. Type A natural ferrite absorbent is a kind of magnetic material with low dielectric constants, high magnetic conductivity and high EM loss. Its EM pa-rameters are ε ′ = 58.60, ε ″ = 10.0, μ ′ = 1.2-1.5, μ ″ = 1.0-1.2, respectively. In order to illuminate the regulation mechanism of EM parameters, we studied the chemical and mineral composition of type A ferrite absorbent. There is high concentration of natural impurities, which regulate the EM parameters of type A ferrite greatly. For comparison, the other types of natural ferrite, single-phase magnetite and two-phase iron minerals (ilmen-ite and magnetite), have few impurity. Thus regulation mechanism of EM parameters was absent in these ferrites. As a result, the regulation of EM parameters is advantageous to develop type A natural ferrite as excellent absorbent, lowers the reflectivity coefficients and enhances the absorbing efficiency of MAM made from it. Furthermore, the impurities in type A natural ferrite and its effects on EM parameters are very difficult to simulate in the synthesize ferrite. The carbonyl-iron powder is another kind of absorbent that is used ex-tensively in MAM. To compare the absorbing properties of these two absorbent, type A natural ferrite and carbonyl-iron powder were mixed with rubber and processed into mi-crowave absorbing sheets with the same procedures and tec

关键词： natural impure ferrite, complex permittivity, complex permeability, microwave absorbing materials.

Effect of rock mass structure and block size on the slope stability——Physical modeling and discrete element simulation

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Science china(Technological sciences) 2005年第Z1期48卷 1-17页

作者： li Shihai1, liAn Zhenzhong1,2 & j. G. Wang3.1. {3. of Mechanics, chinese academy of sciences, Beijing 100080, china 2. Graduate School, chinese academy of sciences, Beijing 100060, china 3. Tropical Marine Science {3., national University of Singapore, Singapore 119260 institute of Mechanics Chinese Academy of Sciences Beijing 100080 China Graduate School Chinese Academy of Sciences Beijing 100060 China Tropical Marine Science institute National University of Singapore Singapore 119260 Singapore

This paper studies the stability of jointed rock slopes by using our improved three-dimensional discrete element methods (DEM) and physical modeling. Results show that the DEM can simulate all failure modes of rock slopes with different joint configurations. The stress in each rock block is not homogeneous and blocks rotate in failure development. Failure modes depend on the configuration of joints. Toppling failure is observed for the slope with straight joints and sliding failure is observed for the slope with staged joints. The DEM results are also compared with those of limit equilibrium method (LEM). Without considering the joints in rock masses, the LEM predicts much higher factor of safety than physical modeling and DEM. The failure mode and factor of safety predicted by the DEM are in good agreement with laboratory tests for any jointed rock slope.

关键词： rock masses, slope stability, DEM simulation, block size effect, joints configuration effect, limit equilibrium method.

Dynamics and synchronization in a memristor-coupled discrete heterogeneous neuron network considering noise

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chinese Physics B 2024年第2期33卷 537-544页

作者：晏询李志军李春来 School of Automation and Electronic Information Xiangtan UniversityXiangtan 411105China School of Computer Science&School of Cyberspace Science Xiangtan UniversityXiangtan 411105China

Research on discrete memristor-based neural networks has received much ***,current research mainly focuses on memristor–based discrete homogeneous neuron networks,while memristor-coupled discrete heterogeneous neuron networks are rarely *** this study,a new four-stable discrete locally active memristor is proposed and its nonvolatile and locally active properties are verified by its power-off plot and DC V–I *** on two-dimensional(2D)discrete Izhikevich neuron and 2D discrete Chialvo neuron,a heterogeneous discrete neuron network is constructed by using the proposed discrete memristor as a coupling synapse connecting the two heterogeneous *** the coupling strength as the control parameter,chaotic firing,periodic firing,and hyperchaotic firing patterns are *** particular,multiple coexisting firing patterns are observed,which are induced by different initial values of the *** synchronization between the two heterogeneous neurons is discussed and it is found that they can achieve perfect synchronous at large coupling ***,the effect of Gaussian white noise on synchronization behaviors is also *** demonstrate that the presence of noise not only leads to the transition of firing patterns,but also achieves the phase synchronization between two heterogeneous neurons under low coupling strength.

关键词： heterogeneous neuron network discrete memristor coexisting attractors synchronization noise

CO observations of massive star forming regions at different evolutionary phases

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Science china(Physics,Mechanics & Astronomy) 2006年第5期49卷 626-640页

作者： CHEn Xi1,2, XU Ye1,3. SHEn Zhiqiang1,3.& li jingjing1,2 1. Shanghai Astronomical Observatory, chinese academy of sciences, Shanghai 20003., china 2. Graduate School of the chinese academy of sciences, Beijing 10003., china 3. joint institute for Galaxy and Cosmology, Shanghai Astronomical Observatory and the University of Science and Technology of china, Shanghai 20003., china Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai China Graduate School of the chinese academy of sciences Beijing China joint institute for Galaxy and Cosmology Shanghai Astronomical Observatory and the University of Science and Technology of China Shanghai China

The 12CO (j=1-0), 13.O (j=1-0) and C18O (j=1-0) emissions in 9 massive star forming regions, which are believed to be at different stages of massive star formation, were mapped with the 13.7 m millimeter wave telescope at Qinghai Station of Purple Mountain Observatory. Of the observed 9 sources, 13.O cores were detected in seven of them, and C18O cores in five of them. And only two sources associated with C18O cores and H2O masers showed the extended structures and strong outflows. This is the first detection of outflow associated with IRAS 22566+5828 in the observing field of S152/S153. The physical parameters of cores and outflows for these sources, derived from Local Thermal Equilibrium (LTE) analysis, are presented. These observing results suggest that the C18O cores will only appear when the gas density is high enough and the probability to have an outflow is very high when the clumps show the C18O and H2O maser simulta- neously.

关键词： star formation cloud core outflow H2O maser

neighbour effects on plant biomass and its allocation for forbs growing in heterogeneous soils

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journal of Plant Ecology 2024年第4期17卷 90-99页

作者： Yongjie liu Chunyan Ma Shiting liu Mingrui liu Hui {3. Mingxia Wang Guoe {3. Hans j.De Boeck Fujiang Hou Zhanhui Tang Zhenxin {3. State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems Key Laboratory of Grassland Livestock Industry InnovationMinistry of Agriculture and Rural AffairsCollege of Pastoral Agriculture Science and TechnologyLanzhou UniversityLanzhou 730020China School of Ecology and Environmental sciences Yunnan UniversityKunming 650091China Plant and Ecosystems(PLECO) Department of BiologyUniversity of AntwerpWilrijk B-2610Belgium State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration School of EnvironmentNortheast Normal UniversityChangchun 130117China Key Laboratory of Biodiversity and Environment on the Qinghai-Tibet Plateau Ministry of EducationLhasa 850011China

Focal plants are considerably affected by their neighbouring plants,especially when growing in heterogeneous soils.A previous study on grasses demonstrated that soil heterogeneity and species composition affected plant biomass and above-and belowground allocation *** now tested whether these findings were similar for *** forb species(*** anglica,limonium bicolor and Suaeda glauca)were grown in pots with three levels of soil heterogeneity,created by alternatively filling resource-rich and resource-poor substrates using small,medium or large patch *** compositions were created by growing these forbs either in monocultures or in *** showed that patch size×species composition significantly impacted shoot biomass,root biomass and total biomass of forbs at different ***,at the pot scale,shoot biomass,root biomass and total biomass increased with increasing patch *** the substrate scale,shoot biomass and total biomass were higher at the large patch size than at the medium patch size,both in resource-rich and resource-poor ***,at the community scale,monocultures had more shoot biomass,root biomass and total biomass than those in the two-or three-species *** results differ from earlier findings on the responses of grasses,where shoot biomass and total biomass decreased with patch size,and more shoot biomass and total biomass were found in resource-rich than resource-poor *** further elucidate the effects of soil heterogeneity on the interactions between neighbour plants,we advise to conduct longer-term experiments featuring a variety of functional groups.

关键词： biomass allocation neighbour effect patch size soil heterogeneity shoot biomass

Plastic deformation behavior of a Cu-10Ta alloy under strong impact loading

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Defence Technology（防务技术） 2024年第2期32卷 368-382页

作者： Ping Song jianghai liu Wenbin li Yiming li Research institute of Chemical Defense Academy of Military ScienceBeijing102205China Ministerial Key Laboratory of ZnDY Nanjing University of Science and TechnologyNanjing210094China

In this work,a Cu-10Ta alloy with a copper to tantalum mass ratio of 9:1 is prepared using powder metallurgy *** properties of the alloy,including density,microstructure,melting point,and constant-volume specific heat,are *** the split Hopkinson pressure bar(SHPB)and flyerplate impact experiments,the relationship between equivalent stress and equivalent plastic strain of the material is studied at temperatures of 298-823.K and under strain rates of 1×10^(-3.-5.2×10^(3.s^(-1),and the Hugoniot relationship at impact pressures of 1.46-17.25 GPa and impact velocities of 108-942 m/s is *** of the Cu-10Ta microstructure that occurs during high-strain-rate impact is *** indicate that the Cu-10Ta alloy possesses good thermal stability,and at ambient temperatures of up to 50%its melting point,stress softening of less than 15%of the initial strength is observed.A modified j-C constitutive model is employed to accurately predict the variation of yield strength with strain *** strong impact,the copper phase is identified as the primary source of plastic deformation in the Cu-10Ta alloy,while significant deformation of the high-strength tantalum particles is less ***,the longitudinal wave speed D is found to correlate linearly with the particle velocity u upon strong *** reveals that the sound speed and spallation strength of the alloy increase with increasing impact pressure.

关键词： Cu-10Ta SHPB Plastic deformation Flyer impact Hugoniot relationship

SEVAR: a stereo event camera dataset for virtual and augmented reality

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Frontiers of Information Technology & Electronic Engineering 2024年第5期25卷 755-762页

作者： Yuda DOnG Zetao CHEn Xin HE lijun li Zichao SHU Yinong CAOl junchi FEnG Shijie liu {3. li jianyu WAnG Hangzhou institute for Advanced Study University of Chinese Academy of SciencesHangzhou 310024China Shanghai institute of Technical Physics Chinese Academy of SciencesShanghai 200083China University of chinese academy of sciences Bejing 100049China Yongjiang Laboratory Ningbo 130021China

Event cameras,characterized by their low latency,large dynamic range,and extremely high temporal resolution,have recently received increasing *** features make them particularly well-suited for virtual/augmented reality(VR/AR)*** facilitate the development of three-dimensional(3.)perception and navigation algorithms in VR/AR applications using event cameras,we introduce the Stereo Event camera dataset for Virtual and Augmented Reality(SEVAR),which comprises a wide variety of head-mounted indoor sequences,including scenarios with rapid motion and a large dynamic range.

关键词： mounted dynamic camera

Recent Beijing Spectroscopy (BES) results

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Science china(Physics,Mechanics & Astronomy) 2008年第6期51卷 567-576页

作者： li WeiGuo institute of High Energy Physics, chinese academy of sciences, Beijing 100049,{3. institute of High Energy Physics Chinese Academy of Sciences Beijing China

Recent experimental results from Beijing Spectroscopy (BES) are reviewed, including the hadron spectroscopy from j/ψ decays, and a number of new states are found or confirmed, including σ, κ, X(183.), ωφ threshold enhancement in j/ψ→γωφ, a broad resonance in j/ψ→K + K ? π 0, decay studies of ψ(2S) and χ Cj , as well as the results of ψ(3.70) non-D $ \bar D $ decays. The current status of BEPCII/BESIII, the major upgrade of BEPC/BESII, is also reported.

关键词： Beijing Spectroscopy hadron spectroscopy charm physics BEPCII