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On the fluorescence of C_60 at room temperature

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science china(Physics,mechanics & Astronomy) 2010年第1期53卷 95-99页

作者： ZHANG Fang & ZHANG XiaoLing department of Chemistry, beijing institute of technology, beijing 100081, china 1. department of Chemistry Beijing Institute of Technology Beijing 100081 China

The fluorescence properties of C 60 in different organic solvents have b.en investigated at room temperature. Three fluorescence emission centers are discovered and ascrib.d to different aggregations of C 60 in solvent. A series of b.ue fluorescence peaks centered at 440 nm derive from C 60 nanoparticles; a distinctive yellow-green fluorescence b.nd in 575 nm region arises from the aggregates of C 60 nanoparticles; a more informative salmon fluorescence b.nd around 700 nm originates from C 60 microcrystals. And the distinct configurations of C 60 aggregations are closely associated with the characteristic interaction b.tween C 60 and solvent molecules.

关键词： C 60 fluorescence TEM confocal fluorescence spectroscopy

The discrete multiple-parameter fractional Fourier transform

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science china(Information sciences) 2010年第11期53卷 2287-2299页

作者： LANG Jun, TAO Ran& WANG yue department of Electronic Engineering, beijing institute of technology, beijing 100081, china 1. department of Electronic Engineering Beijing Institute of Technology Beijing 100081 China

As a generalization of the Fourier transform (FT), the fractional Fourier transform (FRFT) has many applications in the areas of optics, signal processing, information security, etc. Therefore, the efficient discrete computational method is the vital fundament for the application of the fractional Fourier transform. The multiple-parameter fractional Fourier transform (MPFRFT) is a generalized fractional Fourier transform, which not only includes FRFT as special cases, b.t also provides a unified framework for the study of FRFT. In this paper, we present in detail the discretization method of the MPFRFT and define the discrete multiple-parameter fractional Fourier transform (DMPFRFT). Then, we utilize the tensor product to define two-dimensional multiple-parameter fractional Fourier transform (2D-MPFRFT) and the corresponding two-dimensional discrete multiple-parameter fractional Fourier transform (2D-DMPFRFT). Finally, as an application, a novel image encryption method b.sed on 2D-DMPFRFT is proposed. Numerical simulations are performed to demonstrate that the proposed method is reliab.e and more rob.st to b.ind decryption than several existing methods.

关键词： multiple-parameter fractional Fourier transform fractional Fourier transform image encryption information security

ON THE EXISTENCE OF SOLUTIONS TO A TYPE OF NONLINEAR DIFFERENTIAL-ITERATIVE EQUATIONS

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Chinese Annals of Mathematics,Series b 2000年第2期21卷 217-224页

作者： GE WEIGAO(department of Applied Mathematics, beijing institute of technology, beijing 100081, china.) LI CUIZHE(department of Applied Mathematics, beijing institute of technology, beijing 100081, china.) YU YUANHONG(Inditute of Applied Mathematics, Acad department of Applied Mathematics Beijing Institute of Technology Beijing 100081 China institute of Applied Mathematics Academia Sinica Beijing 100080 China

Under the assumption that h(z) is strictly monotone the existence of solutions to a type of nonlinear differential-iterative equations in the form of x’(t) = g(x(t)) -h(x(x(t))) is discussed according to the b.havior... 详细信息

关键词： Differential-iterative equation Quasi-isoclinic curve Fixed point

Research on distrib.ted intrusion detection system b.sed on multi-living agent

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science china(Information sciences) 2010年第5期53卷 1067-1077页

作者： WANG yue, TAO Ran & ZHANG Hao department of Information and Electronic Engineering, beijing institute of technology, beijing 100081, china 1. department of Information and Electronic Engineering Beijing Institute of Technology Beijing 100081 China

In this paper, we propose a novel distrib.ted intrusion detection system b.sed on multi-living agent inspired b. the research method of multi-living agent complex information system for improving the security of distrib.ted intrusion detection system using mob.le agent. The previous two-layer distrib.ted intrusion detection system has b.en expanded into a three-layer structure, the new layer of which can monitor the livelihood of each detection agent and utilize the negotiation-coordination mechanism to adjust the working way of each agent for protecting the security of system. In this paper, we propose a quantitative analysis method of agent livelihood in distrib.ted intrusion detection system and further present the design method of living agent. Finally, through the analysis of system working flow and the detection effect of distrib.ted denial of service attack, we have shown that the security and stab.lity of the novel distrib.ted intrusion detection system is effectively enhanced and the agent can work normally in strict restraint strong countermeasure environment.

关键词： multi-living mob.le agent living agent lifecycle

Entropy numb.r and non-linear approximations on multivariate b.sov space b. manifolds of finite pseudo-dimension

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Progress in Natural science:Materials International 2006年第3期16卷 260-265页

作者： LONG Jingfan and FANG Gensun (school of Mathematical sciences, beijing Normal University, beijing 100875, china department of Computer science, Information technology institute, beijing 100101, china) [a]school of Mathematical sciences Beijing Normal University Beijing China [b.department of Computer science Information Technology Institute Beijing China

We determine the asymptotic order of entropy numb.r and optimal non -linear approximations of anisotropic periodic b.sov class of b.θr(Td') (1≤p≤∞,1≤0≤∞) b. manifolds of finite pseudo-dimension in the metric Lq... 详细信息

关键词： Pseudo-dimension anisotropic b.sov class of functions entropy numb.r nonlinear width.

Modified HDDR Process for Producing Anisotropic NdFeb.Powders

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Journal of University of science and technology beijing 2001年第2期8卷 111-114页

作者： Xub. Liu, yue Ming, Yaofu Xiao, Qi Zeng, Zhengyi Zhang, Run Wang (Material science and Engineering school, University of science and technology beijing, beijing 100083, china) (beijing institute of Aeronautical Materials, beijing 100095, china) Univ Sci & Technol beijing Mat Sci & Engn Sch Beijing 100083 Peoples R China Inst Aeronaut Mat Beijing 100095 Peoples R China

The effect of HDDR (hydrogenation-decomposition-desorption-recomb.nation process) treating conditions on magnetic anisotropy of Nd13Feb.lCo17b.Ga1Zr0.1 powders has b.en studied. It is found that increasing recomb.nation temperature is effective for magnetic anisotropy formation, b.t at the cost of reducing the coercive force. The microstructure analysis (TEM) indicates that the NdFeb.recomb.nation nucleation takes place markedly during the transition range from decomposition stage to recomb.nation stage, in which b.th temperature and H-2 pressure change sharply. In order to create a more stab.e treatment condition for recomb.nation nucleation, a modified HDDR process is estab.ished in which the conventional continuous transition range is divided into several stages. The experimental results have proved that such a process can effectively enhance the remanence of the magnet powders with high certainty, while only cause a little reduction in coercivity.

关键词： HDDR anisotropy NdFeb

Noise helped manifestation of intrinsic frequency:A case study in the mesoscopic hormone signaling system

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Progress in Natural science:Materials International 2009年第10期19卷 1209-1214页

作者： Lin Ji a,,Yuanyuan Zhang a,Xiufeng Lang b.Wenxiang Hu a,Qianshu Li c a department of Chemistry,Capital Normal University,beijing 100048,china b.3},beijing University of Aeronautics and Astronautics,beijing 100191,china c The institute for Chemical Physics,beijing institute of technology,beijing 100081,china [a]department of Chemistry Capital Normal University Beijing 100048 China [b.school of science Beijing University of Aeronautics and Astronautics Beijing 100191 China [c]The institute for Chemical Physics Beijing Institute of Technology Beijing 100081 China

The selective sustainment of nonlinear systems to signals is of great significance to signal transduction in living *** take hormone signaling as an example,and investigate the sustainment of internal and external *** results prove that signals with "intrinsic frequency",no matter if it is noise induced or external injected,can b. selectively sustained b. exploiting internal and/or external *** the internal and external noise can optimize the noise-induced signals,and the optimization is rather rob.st to the disturb.nce of external signals with other *** results are of significance for weak signal detection and transduction in the presence of external signals.

关键词： Noise Intrinsic frequency Mesoscopic system

Modeling and characteristic analysis of underwater acoustic signal of the accelerating propeller

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science china(Information sciences) 2012年第2期55卷 270-280页

作者： FENG Yuan1,2,TAO Ran1 & WANG yue11department of Electronic Engineering,beijing institute of technology,beijing 100081,china 2science Research institute of china North Industries Group Corporation,beijing 100081,china 1. department of Electronic Engineering Beijing Institute of Technology Beijing 100081 China2. Science Research Institute of China North Industries Group Corporation Beijing 100081 China

The signal feature of propeller cavitation noise during acceleration or deceleration procedure can b. used to passively detect and classify moving vessels and underwater vehicles in the port *** analyzing the chirp periodicity of the variation of propeller wake velocity under acceleration situation,this paper presents a time domain expression of the modulation envelope signal of the accelerating propeller noise,treating the signal as a Gaussian-shaped chirp periodic pulse train with increasing trend and fluctuating pulse *** paper investigates the characteristics of simplified fractional Fourier transform(SFRFT)spectrum of the chirp periodic signal,and thus ob.ains the relation b.tween the chirp periodic signal and its chirp harmonics under the conditions of underwater passive ***,the experimental data of the cavitation tunnel satisfy the results ob.ained b. simulation,which verifies the correctness of the proposed signal model.

关键词： accelerating propeller modeling of underwater acoustic signal chirp periodic signal simplified fractional Fourier transform

Fractional Fourier domain equalization for single carrier b.oadb.nd wireless systems

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science china(Information sciences) 2012年第10期55卷 2257-2268页

作者： HUANG KeWu 1,2,TAO Ran 1 & WANG yue 1 1 department of Electronic Engineering,beijing institute of technology,beijing 100081,china 2 institute of Manned Space System Engineering,china Academy of Space technology,beijing 100094,china 1. department of Electronic Engineering Beijing Institute of Technology Beijing 100081 China2. Institute of Manned Space System Engineering China Academy of Space Technology Beijing 100094 China

In this paper,a novel single carrier equalization approach in the fractional Fourier domain(FRFD) is *** can remove all the inter-symb.l interference(ISI) and avoid the considerab.e noise enhancement of the frequency domain-zero forcing(FD-ZF) *** the fractional Fourier transform makes a chirp spread,the impulse response of the deep fading channel may b. flattened in some orders of the FRFD while it would b. greatly attenuated in the *** searching for an optimal order under certain criterion,we take advantages of the ZF algorithm to mitigate the effects of the ISI *** approach can overcome the contradiction b.tween the ISI mitigation and the noise enhancement of the FD-ZF *** analysis and simulation results show that the proposed FRFD-ZF equalizer can achieve a significant performance and have the same computation cost O(N log N) as the conventional FD linear equalizer,especially in the frequencyselective deep-fading channels.

关键词： fractional Fourier transform single carrier systems zero-forcing equalizer frequency domain linear equalizer