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The Multifractal Analysis of the Occupation Measure of a Lévy process

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Wuhan University Journal of Natural sciences 2000年第3期5卷 253-256页

作者： Hu Xiao\|yu institute of Applied Mathematics, chinese academy of sciences, beijing 100080, china chinese academy of sciences Institute of Applied Mathematics Beijing China (GRID:grid.9227.e) (ISNI:***)

We introduce the results on the multifractal structure of the occupation measures of a Brownian Motion, a stable process, a general subordinator and a stochastic process derived from random reordering of the Cantor se... 详细信息

关键词： occupation measure Levy process Brownian motion stable process subordinator

RECOVERY OF AMORPHOUS POLY(ETHYLENE TEREPHTHALATE)FILM UNIAXIALLY DRAWN JUST BELOW THE GLASS TRANSITION TEMPERATURE

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chinese Journal of Polymer Science 2000年第1期18卷 69-75页

作者： Nan-jian Sun Juan Yang De-yan Shen Ren-yuan Qian institute of Chemistry, chinese academy of sciences, beijing 100080, china chinese Acad Sci Inst Chem Beijing 100080 Peoples R China

Isothermal recovery in the macroscopic length of homogeneously deformed specimens of amorphous poly(ethylene terephthalate) (PET) film sample uniaxially drawn at 69 degrees C to the draw ratios lambda(0) = 1.26-2.20 were studied at temperatures around the glass transition temperature (T-g = 73 degrees C). Experimental results indicate that the length recovery look place in two distinct steps: a fast first step (fast relaxation) followed by a slow second step (slow relaxation). The relaxation processes were accompanied by the reversion of trans-conformers (1340 cm(-1)) to gauche, and the dichroic function of the 1340 cm(-1) band characterizing the segmental orientation along the chain direction decreased to a very low value at the end of the fast relaxation. This fact led us to assign the fast relaxation as the segmental orientation while the slow relaxation as relaxation of the global chain orientation. It was found that the slow relaxation follows a single exponential function, with relaxation times strongly dependent on the temperature resembling the glass transition process. The fast relaxation does not follow a single exponential decay, presumably a distribution of relaxation times is involved.

关键词： poly(ethylene terephthalate) uniaxial drawing recovery orientation

Pattern phenomena in an rf discharge dusty plasma system

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Science china(Physics,Mechanics & Astronomy) 2006年第5期49卷 588-596页

作者： HUANG Feng1,2, YE Maofu2 & WANG Long2 1. College of Science, china Agricultural University, beijing 100083, china 2. institute of Physics, chinese academy of sciences, beijing 100080, china 1. College of Science China Agricultural University Beijing 100083 China 2. institute of Physics Chinese Academy of Sciences Beijing 100080 China

Various dust patterns are observed in an rf discharge dusty plasma system. According to the dust growth process from small to large in size, the formation of different dust patterns can be divided into two stages: the small-particle stage (or dust cloud stage), and the large-particle stage (or dust crystal stage). The evolution relations between different dust patterns with gas pressure changing are investigated. Dust voids, dust acoustic waves and strong turbulence modes are presented at the small-particle stage. The self-organized dust lattices and dust clusters are investigated at the large-particle stage. The static structure of a dust lattice is characterized by means of the pair correlation function. Dust clusters formed by particles with different numbers and the regular evolution of the clusters with gas pressure are also investigated. The packing sequences of dust clusters are verified through two-dimensional confined molecular dynamics simulations.

关键词： dusty plasma dust patterns

Gasdynamic characteristics of toroidal shock and detonation wave converging

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Science china(Physics,Mechanics & Astronomy) 2005年第6期48卷 739-749页

作者： TENG Honghui1,2 & JIANG Zonglin2 1. Key Laboratory of High Temperature Gas Dynamics, institute of Mechanics, chinese academy of Sci- ences, beijing 100080, china 2. Graduate University of chinese academy of sciences, beijing 100039, china 1. Key Laboratory of High Temperature Gas Dynamics Institute of Mechanics Chinese Academy of Sciences 100080 Beijing China 2. Graduate University of chinese academy of sciences 100039 Beijing China

The modified CCW relation is applied to analyzing the shock, detonation wave converging and the role of chemical reactions in the process. Results indicate that the shock wave is strengthened faster than the detonation wave in the converging at the same initial Mach number. Euler equations implemented with a detailed chemical reaction model are solved to simulate toroidal shock and detonation wave converging. Gasdynamic characteristics of the converging are investigated, including wave interaction patterns, observable discrepancies and physical phenomena behind them. By comparing wave diffractions, converging processes and pressure evolutions in the focusing area, the different effects of chemical reactions on diffracting and converging processes are discussed and the analytic conclusion is demonstrated through the observation of numerical simulations.

关键词： converging, CCW relation, shock wave, detonation wave.

Effects of bacterially produced precipitates on the metabolism of sulfate reducing bacteria during the bio-treatment process of copper-containing wastewater

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Science china Chemistry 2010年第12期53卷 2608-2615页

作者： SHENG YuXing,CAO HongBin,LI YuPing & ZHANG Yi National engineering Laboratory for Hydrometallurgical Cleaner Production Technology Key Laboratory of Green process and engineering,institute of process engineering,chinese academy of sciences,beijing 100190,china 1. National engineering Laboratory for Hydrometallurgical Cleaner Production Technology Key Laboratory of Green process and engineering Institute of Process Engineering Chinese Academy of Sciences Beijing 100190 China

A large volume of bacterially produced precipitates are generated during the bio-treatment of heavy metal *** composition of the bacterially produced precipitates and its effects on sulfate reducing bacteria (SRB) in copper-containing waste stream were evaluated in this *** elemental composition of the microbial precipitate was studied using electrodispersive X-ray spectroscopy (EDX),and it was found that the ratio of S:Cu was *** with the results of copper distribution in the SRB metabolism culture,which was analyzed by the sequential extraction procedure,copper in the precipitates was determined as covellite (CuS).The bacterially produced precipitates caused a decrease of the sulfate reduction rate,and the more precipitates were generated,the lower the sulfate reduction rate *** particle sizes of bacterially generated covellite were ranging from 0.03 to 2 m by particles size distribution (PSD) analysis,which was smaller than that of the SRB *** electron microscopy (TEM) analysis showed that the microbial covellite was deposited on the surface of the *** effects of the microbial precipitate on SRB metabolism were found to be weakened by increasing the precipitation time and adding microbial polymeric substances in later *** results provided direct evidence that the SRB activity was inhibited by the bacterially produced covellite,which enveloped the bacterium and thus affected the metabolism of SRB on mass transfer.

关键词： sulfate reducing bacteria covellite heavy metal wastewater

Periodicity and map for discovery of new ionic liquids

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Science china Chemistry 2006年第2期49卷 103-115页

作者： ZHANG Suojiang, SUN Ning, ZHANG Xiangping & Lü Xingmei Research Laboratory for Green Chemical engineering and Technology, institute of process engineering, chinese academy of sciences, beijing 100080, china Correspondence should be addressed to Zhang Suojiang 1. Research Laboratory for Green Chemical engineering and Technology Institute of Process Engineering Chinese Academy of Sciences Beijing 100080 China

There is virtually no limit in the number of ionic liquids. How to select proper ones or discover new ones with desirable properties in such a large pool of ionic liquids? It has become a bottleneck in the researches and applications of ionic liquids. Mendeleev’s periodic law states that the properties of the elements vary periodically. Whether the similar regularity exists among ionic or mo-lecular fragments of compounds is an interesting topic. In this work, we attempted to establish a pe-riodicity and draw a “map” of ionic liquids for providing definite guidance to discover, design, and se-lect the proper ionic liquids rather than trial-and-error. If a complete regularity of the system of ionic liquids can be finally established in the future, we are near an epoch in understanding the existing differences and the reasons for the similarity of the ions or molecular fragments.

关键词： ionic liquids molecular fragment periodicity map

How big are the Csorgo-Revesz increments of two-parameter Wiener processes?

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Science china Mathematics 2004年第6期47卷 894-907页

作者： WANG WenshengDepartment of Mathematics, Hangzhou Teacher’s College, Hangzhou 310012, china institute of Applied Mathematics, chinese academy of sciences, beijing 100080, china Dept. of Math. Hangzhou Teacher's Coll. Hangzhou 310012 China Inst. of Appl. Math. Chinese Acad. of Sci. Beijing 100080 China

In this paper, we prove a theorem on the set of limit points of the increments of a two-parameter Wiener process via establishing a large deviation principle on the increments of the two-parameter Wiener process.

关键词： two-parameter Wiener process increment functional law of the iterated logarithm large deviation.

Ionization state of cosmic hydrogen by early stars and quasars

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Research in Astronomy and Astrophysics 2009年第6期9卷 665-681页

作者： Xiao-Chun Mao1,2 1 National Astronomical Observatories, chinese academy of sciences, beijing 100012, china 2 Graduate University of chinese academy of sciences, beijing 100049, china National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China Graduate University of chinese academy of sciences Beijing 100049 China

Cosmic hydrogen is reionized and maintained in its highly ionized state by the ultraviolet emission attributed to an early generation of stars and quasars. The Lyα opacity observed in absorption spectra of high-redshift quasars permits more stringent constraints on the ionization state of cosmic hydrogen. Based on density perturbation and structure formation theory, we develop an analytic model to trace the evolution of the ionization state in the post-overlap epoch of reionization, in which the bias factor is taken into account. For quasars, we represent an improved luminosity function by utilizing a hybrid approach for the halo formation rate that is in reasonable agreement with the published measurements at 2 ≤ z ≤ 6. Comparison with the classic Press-Schechter mass function of dark matter halos, we demonstrate that the biased mass distribution indeed enhances star formation efficiency in the overdense environment by more than 25 per cent following the overlap of ionized bubbles. In addition, an alternative way is introduced to derive robust estimates of the mean free path for ionizing photons. In our model, star-forming galaxies are likely to dominate the ionizing background radiation beyond z = 3, and quasars contribute equally above a redshift of z ～ 2.5. From 5 ≤ z ≤ 6, the lack of evolution in photoionization rate can thus be explained by the relatively flat evolution in star formation efficiency, although the mean free path of ionizing photons increases rapidly. Moreover, in the redshift interval z ～ 2 - 6, the expected mean free path and Gunn-Peterson optical depth obviously evolve by a factor of ～ 500 and ～50 respectively. We find that the relative values of critical overdensities for hydrogen ionization and collapse could be 430% at z ≈2 and 2% at z ≈6, suggesting a rapid overlap process in the overdense regions around instant quasars following reionization. We further illustrate that the absolute estimates of the fraction of neutral hydrogen computed fr

关键词： cosmology theory -- formation galaxies -- quasars general -- diffuse radiation -- intergalactic medium

A formal model of fair exchange protocols

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Science in china(Series F) 2005年第4期48卷 499-512页

作者： QING Sihan1,2,3 & LI Gaicheng1,2,3 1. engineering Research Center for Information Security Technology, institute of Software, chinese Aca- demy of sciences, beijing 100080, china 2. beijing Zhongke Ansheng Corporation of Information Technology, beijing 100080, china 3. Graduate School of the chinese academy of sciences, beijing 100039, china 1. engineering Research Center for Information Security Technology Institute of Software Chinese Academy of Sciences 100080 Beijing China 2. beijing Zhongke Ansheng Corporation of Information Technology 100080 Beijing China 3. Graduate School of the chinese academy of sciences 100039 Beijing China

Based on the study of existing fair exchange protocols, this paper sets up an accurate formal model by stepwise refinement. In the process of refinement an unreliable channel is employed to simulate an attack behavior. The model provides a novel formal definition of exchanged items, and presents the formal goals for fairness, accountability, etc., reflecting the inherent requirements for fair exchange protocols across-the-board. In order to check, prove, and design fair exchange protocols effectively and efficiently, the model puts forward a novel property of abuse-freeness which applies to all fair exchange protocols, gives a formal definition for trust strand of the third party, and presents general criteria of designing a secure and effective fair exchange protocol. Taking a typical fair exchange protocol as an example, this paper presents the analysis steps of fair exchange protocols appealing to our model. An unknown attack is uncovered. The analysis reveals the process of a complete attack, discovering deeper reasons for causing an attack. Finally, we modify the flawed protocol and the revised protocol ensures the desirable properties.

关键词： events local causal relation local temporal relation global relation exchanged item security goals.