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Variable bit rate video traffic modeling by multiplicative multifractal model

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Journal of Systems Engineering and Electronics 2006年第1期17卷 75-79页

作者： Huang xiaodong zhou Yuanhua Zhang Rongfu Inst. of Image Communication and Information Processing Shanghai Jiaotong Univ. Shangha 200030 P. R. China

Multiplicative multifractal process could well modal video traffic. The multiplier distributions in the multiplicatire multifractal model for video traffic are investigated and it is found that Gaussian is not suitable for describing the multipliers on the small time scales. A new statistical distribution-symmetric Pareto distribution is introduced. It is applied instead of Gaussian for the multipliers on those scales. Based on that, the algorithm is updated so that symmetric pareto distribution and Gaussian distribution are used to model video traffic but on different time scales. The simulation results demonstrate that the algorithm could model video traffic more accurately.

关键词： multiplicative multifractal model video traffic network traffic model symmetric pareto distribution

Zircon U–Pb Geochronology and Petrogenesis of Early–Midlle Permian Arc–Related Volcanic Rocks in Central Jilin: Implications for the Tectonic Evolution of the Eastern Segment of Central Asian Orogenic Belt

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Acta Geologica Sinica(English Edition) 2020年第4期94卷 1207-1222页

作者： SHI Chenglong DING Xiaozhong LIU Yanxue zhou xiaodong NIE Lijun Institute of Geology Chinese Academy of Geological Sciences Beijing 100037China Survey of Regional Geological and Mineral Resource of Jilin Province Changchun 130022China

This paper presents age and geochemical data of a recently identified Late Paleozoic volcanic sequence in central Jilin Province, with aims to discuss the petrogenesis and to constrain the tectonic evolution of the Central Asian Orogenic Belt in this area. Firstly, the volcanic rocks have zircon U-Pb ages of 290–270 Ma. Secondly, they are characterized by(a) ranging in composition from the low-K tholeiite series to high-K calc-alkaline series;(b) enrichment in light rare earth elements and depletion of heavy rare earth elements, with negative Eu anomalies;and(c) negative Nb, Ta, and Ti anomalies. Finally, the volcanic rocks yield εHf(t) values of +7.1 to +17. These data suggest that the central Jilin volcanic rocks were possibly derived from predominant partial melting of a depleted lithospheric mantle that might have been modified by subducted slab–derived fluids. Combined with previous studies, the Late Paleozoic–Early Mesozoic magmatism in Central Jilin can be divided into two stages:(a) a volcanic arc stage(290–270 Ma) represented by low-K to high–K, tholeiite to calc–alkaline plutons and(b) a syn–collisional stage(260–240 Ma) represented by high-K calc–alkaline I-type granites. Furthermore, the timing and the tectonic setting of the above magmatic rocks show that the arc was probably produced by the northward subduction of the Paleo-Asian Ocean and that the final closure of the Paleo-Asian Ocean occurred prior to the Early Triassic.

关键词： volcanic rocks zircon U-Pb age tectonic evolution Paleo–Asian Ocean

Synthesis of silica powder with high pore volume by skeleton reinforcement

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Chinese Journal of Chemical Engineering 2022年第2期35卷 219-226页

作者： Hongwei Shan xiaodong zhou Hao Jiang Yanjie Hu Haibo Jiang Chunzhong Li Shanghai Engineering Research Center of Hierarchical Nanomaterials Key Laboratory for Ultrafine Materials of Ministry of EducationSchool of Chemical EngineeringEast China University of Science&TechnologyShanghai 200237China School of Materials Science and Engineering East China University of Science&TechnologyShanghai 200237China State Key Laboratory of Chemical Engineering School of Chemical EngineeringEast China University of Science&TechnologyShanghai 200237China

In this paper,a method composed of gelation of basic skeleton(first step)and skeleton reinforcement process(second step)was introduced to synthesize silica powder with high pore volume through the reaction between water glass and sulfuric *** organic solvents were involved in the entire preparation process and the final product was collected by spray *** effect of concentration of base solution,gelation point p H value and skeleton reinforcement time on the BET specific surface area and pore volume of the prepared silica powder were investigated *** results show that,a basic skeleton with good dispersibility and high porosity was obtained when the concentration of base solution was 0.1 mol·L^(-1) and the gelation p H value reached *** the basic skeleton grew into a more uniform porous structure after 30 min skeleton *** these optimum conditions,silica powder prepared by skeleton reinforcement method had a BET specific surface area of 358.0 m^(2)·g^(-1),and its pore volume reached 2.18 cm^(3)·g^(-1),which was much higher than that of prepared by skeleton-free method(1.62 cm^(3)·g^(-1))and by direct gelation method(0.31 cm^(3)·g^(-1)).

关键词： Water glass Silica powder High pore volume Skeleton reinforcement Spray drying

Geochronology, Geochemistry and Sr-Nd-Hf Isotopes of Early–Middle Triassic Adakitic Plutons in Central-eastern Jilin Province, NE China: Constraints on the Non-synchronous Closure of Paleo-Asian Ocean

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Acta Geologica Sinica(English Edition) 2022年第5期96卷 1615-1630页

作者： SHI Chenglong DING Xiaozhong zhou xiaodong NIE Lijun ZHANG Jibiao Institute of Geology Chinese Academy of Geological SciencesBeijing 100037China Survey of Regional Geological and Mineral Resurce of Jilin Province Changchun 130022China

The Changchun–Yanji suture zone(CYSZ) in NE China is considered as the suture between the North China Craton(NCC) and Central Asian Orogenic Belt(CAOB). The geochronology, geochemistry and Sr-NdHf isotopes of Early–Middle Triassic adakitic plutions from the CYSZ, are presented in this paper to discuss their petrogenesis and tectonic setting, as well as to constrain the timing and style of the Paleo-Asian Ocean's final closure. In Early Triassic, the Dayushan pluton(ca. 250 Ma) from western CYSZ has negative ε_(Nd)(t) values, bidirectional provenances(NCC and CAOB) of ε_(Hf)(t), which are formed in a collision tectonic setting. In contrast, in eastern CYSZ, the early Triassic samples in Liangshan(ca. 242 Ma) were high Mg~# values, positive ε_(Nd)(t), single provenances(CAOB) of ε_(Hf)(t) resulting from a subduction setting. In the Middle Triassic, the Atype granites in western CYSZ are found in previous studies representing a post-collisional extensional environment, whereas syn-collisional Lianyanfeng granites(ca. 237 Ma) in eastern CYSZ with low ISr and large scale ε_(Nd)(t) and ε_(Hf)(t) values from bidirectional provenances(NCC and CAOB), represent a collisional setting. The Paleo-Asian Ocean's occurred in a scissor-like fashion along the CYSZ during the Triassic period.

关键词： granitoids tectonic evolution Paleo-Asian Ocean Central Asian Orogenic belt

Sign-reversible valley-dependent Berry phase effects in 2D valley-half-semiconductors

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npj Computational Materials 2021年第1期7卷 1435-1441页

作者： xiaodong zhou Run-Wu Zhang Zeying Zhang Wanxiang Feng Yuriy Mokrousov Yugui Yao Centre for Quantum Physics Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement(MOE)School of PhysicsBeijing Institute of Technology100081 BeijingChina Beijing Key Lab of Nanophotonics&Ultrafine Optoelectronic Systems School of PhysicsBeijing Institute of Technology100081 BeijingChina College of Mathematics and Physics Beijing University of Chemical Technology100029 BeijingChina Peter Grünberg Institut and Institute for Advanced Simulation Forschungszentrum Jülich and JARA52425 JülichGermany Institute of Physics Johannes Gutenberg University Mainz55099 MainzGermany

Manipulating valley-dependent Berry phase effects provides remarkable opportunities for both fundamental research and practical ***,by referring to effective model analysis,we propose a general scheme for realizing topological magneto-valley phase *** importantly,by using valley-half-semiconducting VSi2N4 as an outstanding example,we investigate sign change of valley-dependent Berry phase effects which drive the change-in-sign valley anomalous transport characteristics via external means such as biaxial strain,electric field,and correlation *** a result,this gives rise to quantized versions of valley anomalous transport *** findings not only uncover a general framework to control valley degree of freedom,but also motivate further research in the direction of multifunctional quantum devices in valleytronics and spintronics.

关键词： Berry phase reversible

Modeling pyrolysis of charring material in fire

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Chinese Science Bulletin 2002年第5期47卷 425-429页

作者： Lizhong Yang Xiaojun Chen xiaodong zhou Qing’an Wang Weicheng Fan Univ Sci & Technol State Key Lab Fire Sci Hefei 230026 Peoples R China

A modified model of pyrolysis for charring materials in fire has been proposed in this note. In this model some special factors which show the effect on pyrolysis are considered, i.e. heat loss by convection and radiation caused by surface temperature rise and shrinkage of char surface are considered. Experimental device is designed specially for validating the reliability of the model. Effects of density of materials and heat radiation on pyrolysis of materials have also been investigated.

关键词： charring materials pyrolysis fire thermal radiation model.

Isolated ultrasmall Bi nanosheets for efficient CO_(2)-to-formate electroreduction

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Nano Research 2022年第2期15卷 1409-1414页

作者： Jinze Liu Yuhang Li Yating Wang Chuqian Xiao Miaomiao Liu xiaodong zhou Hao Jiang Chunzhong Li Key Laboratory for Ultrafine Materials of Ministry of Education Shanghai Engineering Research Center of Hierarchical NanomaterialsFrontiers Science Center for Materiobiology and Dynamic ChemistrySchool of Materials Science and EngineeringEast China University of Science&TechnologyShanghai 200237China School of Chemical Engineering East China University of Science&TechnologyShanghai 200237China

Electrochemical reduction of CO_(2) to valuable formate as liquid fuel is a promising way to alleviate the greenhouse *** edge active sites in bismuth(Bi)nanosheets play a critical role in the electrochemical reduction of CO_(2) into formate,which enable the operation of CO_(2) reduction with high cathodic energy efficiency,especially under large current densities of≥200 mA/cm^(2).However,the undesirable reconstruction of small Bi nanosheets into large nanosheets leads to the decreasing of edge active sites during *** we report stable isolated ultrasmall bismuth nanosheets-synthesized by in-situ electrochemical transformation of ligands covered bismuth vanadate-on silver nanowires as an efficient electrocatalyst for CO_(2)-to-formate *** cooperative electrocatalyst achieves a formate current density of 186 mA/cm^(2) and a cathodic energy efficiency of 75%for formate,which is the only best compared to the literature ***。Raman and morphologic measurements demonstrate that the excellent energy utilization of the electrocatalyst is originated from the rich edge active sites with Bi-O species of the ultrasmall Bi nanosheets.

关键词： bismuth CO_(2)reduction electrocatalysis formate ultrasmall nanosheets

Influence of Annealing Temperature on the Properties of TiO_2 Films Annealed by ex situ and in situ TEM

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Journal of Wuhan University of Technology(Materials Science) 2012年第6期27卷 1014-1019页

作者：彭堂超 XIAO Xiangheng REN Feng XU Jinxia zhou xiaodong MEI Fei 蒋昌忠 School of Physics and Technology Wuhan University Huazhong Institute of Electro-Optics-Wuhan National Laboratory for Optoelectronics School of Electrical&Electronic Engineer Hubei University of TechnologyWuhan 430068China

TiO2 thin films were deposited on quartz substrates by DC reactive magnetron sputtering of a pure Ti target in Ar/O2 plasma at room temperature. The TiO2 films were annealed at different temperatures ranging from 300 to 800 ℃ in a tube furnace under flowing oxygen gas for half an hour each. The effect of annealing temperatures on the structure, optical properties, and morphologies were presented and discussed by using X-ray diffraction, optical absorption spectrura, and atomic force microscope. The films show the presence of diffraction peaks from the （101）, （004）, （200） and （105） lattice planes of the anatase TiO2 lattice. The direct band gap of the annealed films decreases with the increase of annealing temperature. While, the roughness of the films increases with the increases of annealing temperature, and some significant roughness changes of the TiO2 film surfaces were observed after the annealing temperature reached 800 ℃. Moreover, the influences of annealing on the microstructures of the TiO2 film were investigated also by in situ observation in transmission electron microscope.

关键词： TiO2 films DC reactive magnetron sputtering anatase in situ TEM annealing

Simultaneous Fluorescence Detection of Mercury(Ⅱ) and Silver Ions Based on Rhodamine B Isothiocyanate and 5-Carboxyfluorescein-ss DNA Modified Probe

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Wuhan University Journal of Natural Sciences 2016年第6期21卷 499-504页

作者： CHEN Yinran MAO Kang zhou xiaodong SHEN Aiguo HU Jiming College of Chemistry and Molecular Sciences Wuhan University

A new fluorescence sensor is developed for simultaneous detection of Hg^2＋ and Ag^＋. During the detection process,Hg^2＋ forms complexes with the fluorescent dye rhodamine B isothiocyanate（RBITC） modified onto the surface of gold nanoparticles（Au NPs）,resulting in RBITC＇s displacement from the surface of Au NPs and the recovery of fluorescence. Meanwhile,Ag^＋ forms ＂C-Ag^＋-C＂ complex with C-rich 5-carboxyfluorescein（FAM）-ss DNA modified onto the surface of Au NPs,which keeps the fluorescent dye FAM close to the Au NPs and results in quench of fluorescence. The experimental results show a wide linear range and a good sensitivity. The limit of detection is 1.06 nmol/L for Ag^＋ and 0.48 nmol/L for Hg^2＋. This detection method is not only easy to operate but also efficient.

关键词： fluorescence sensor simultaneous detection metalions