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Stochastic resonance in surface catalytic oxidation of carbon monoxide induced by colored noise

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Science china Chemistry 2004年第2期47卷 106-112页

作者： GONG Yubing1,2, HOU Zhonghuai1 & XIN Houwen1 1. department of Chemical physics, university of Science and technology of china, Hefei 230026, china 2. department of physics, Yantai Teachers university, Yantai 264025, china department of Chemical physics University of Science and Technology of China Hefei China department of physics Yantai Teachers University Yantai China

The dynamical behavior of surface catalytic oxidation reaction of Pt(110)/CO+O2 modulated by colored noise, under the condition of specific temperature, has been investigated when the partial pressure of CO gas is near the supercritical Hopf bifurcation point. By computer simulation the oscillation and stochastic resonance induced by colored noise are observed. The influences of the intensity and correlation time of colored noise on stochastic resonance are discussed. The range of sensitivity of the system to the environmental fluctuation is analyzed.

关键词： colored noise, stochastic resonance, surface catalytic reaction of Pt(110)/CO+O2, supercritical Hopf bifurcation, signal-to-noise ratio (SNR).

Internal noise stochastic resonance in CO oxidation on nm-sized palladium particles

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Science china Chemistry 2005年第5期48卷 395-401页

Based on a stochastic mesoscopic model, the influence of internal noise on the oscillatory kinetics of the catalytic oxidation of CO on nm-sized palladium particles is studied, using the chemical Langevin equations, Poisson approximation algorithm, and exact stochastic simulation algorithm. The reaction rate oscillations are of stochastic nature due to considerable internal noise in such mesoscopic systems. It is found that the performance of the stochastic oscillations undergoes a maximum with the variation of internal noise level for a given CO partial pressure, which demonstrates the occurrence of internal noise stochastic resonance. This phe-nomenon implies that optimal internal noise would favor the reaction rate oscillation of CO oxi-dation on nm particles. Such a phenomenon is robust to the change of external parameters, such as CO pressures.

关键词： nanometer-sized palladium particles, surface catalytic CO oxidation, internal noise, stochastic resonance, chemical Langevin equation.

First-principles calculations on implanted TiO_2 by 3d transition metal ions

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Science china(physics,Mechanics & Astronomy) 2009年第6期52卷 838-842页

作者： HOU XingGang1,2, HUANG MeiDong1, WU XiaoLing2 & LIU AnDong2 1 department of physics, tianjin Normal university, tianjin 300387, china 2 Key Laboratory of Beam technology and Material Modification of Ministry of Education, Beijing Normal university, Beijing 100875, china department of physics Tianjin Normal University Tianjin China Key Laboratory of Beam technology and Material Modification of Ministry of Education Beijing Normal University Beijing China

3d transition metal (V, Cr and Fe) ions are implanted into TiO2 by the method of metal ion implantation. The electronic band structures of TiO2 films doped 3d transition metal ions have been analyzed by ab initio band calculations based on a self-consistent full-potential linearized augmented plane-wave method within the first-principle formalism. Influence of implantation on TiO2 films is examined by the method of UV-visible spectrometry. The results of experiment and calculation show that the optical band gap of TiO2 films is narrowed by ion implantation. The calculation shows that the 3d state of V, Cr and Fe ions plays a significant role in red shift of UV-Vis absorbance spectrum.

关键词： 3d transition metal ions implantation TiO2 FP-LAPW electronic structure

Irregular wavelet frames on L^2 (R^n)

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Science china Mathematics 2005年第2期48卷 277-287页

作者： YANG Deyun & ZHOU Xingwei department of Information & technology, Nankai university, tianjin 300071, china department of Mathematics, Nankai university, tianjin 300071, china department of Computer Science, Taishan College, Taian 271000, china department of Information & technology Nankai University Tianjin China department of Mathematics Nankai University Tianjin China department of Computer Science Taishan College Taian China

In this paper, we present the conditions on dilation parameter {sj}j that ensure a discrete irregular wavelet system to be a frame on L2(Rn), and for the wavelet frame we consider the perturbations of translation para... 详细信息

关键词： wavelet transform, frame, wavelet frame, irregular dilation.

Formation of bulk ferromagnetic nanostructured Fe_(40)Ni_(40)P_(14)B_6 alloys by metastable liquid spinodal decomposition

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Science china(Technological Sciences) 2009年第7期52卷 1919-1922页

作者： LI Qiang1,2 1 School of physics Science and technology, Xinjiang university, Urumqi 830046, china 2 department of physics, The Chinese university of HongKong, Shatin N.T., HongKong, china School of physics Science and technology Xinjiang University Urumqi China department of physics The Chinese University of HongKong Shatin N.T. HongKong China

Nanostructured Fe40Ni40P14B6 alloy ingots of 3―5 mm in diameter could be synthesized by a metastable liquid state spinodal decomposition method. For undercooling T> 260 K, the microstructure of the undercooled specimen had exhibited liquid state spinodal decomposition in the undercooled liquid state. The microstructure could be described as two intertwining networks with small grains dispersed in them. For undercooling T>290 K, the overall microstructure of the specimen changed into a granular morphology. The average grain sizes of the small and large grains are 30 nm and 80 nm, respectively. These prepared samples are soft magnets with saturation magnetization Bs 0.744 T.

关键词： nanomaterials magnetic materials solidification bulk nanostructured alloy Fe40Ni40P14B6 metastable liquid spinodal decomposition

The phase transition and classification of critical points in the multistability chemical reactions

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Communications in Nonlinear Science and Numerical Simulation 2000年第1期5卷 36-43页

作者： Chunhua ZHANG Fugen WU Chunyan WU and Fa OU department of physics, Guangdong university of technology, Guangzhou510090, china department of Applied physics, South china university of technology, Guangzhou 510641, china department of physics Guangdong University of Technology Guangzhou 510090 China department of Applied physics South China University of Technology Guangzhou 510641 China

In this paper, we study the phase transition and classification of critical points in multistability chemical reaction systems. Referring to the spirit of Landau's theory of phase transitions, this paper deals with the varied transitions and critical phenomena in multistable chemical systems. It is demonstrated that the higher the order of the multistability, the wider the variety of phase transitions will be. A classification scheme of critical points according to the stability criterion and the thermodynamic potential continuity is suggested. It is useful for us to study critical phenomena especially in the non-equilibrium systems including the multi-Stable chemical ones.

关键词： nonlinear chemistry non-equilibrium phase transition critical points

Transition prediction of a hypersonic boundary layer over a cone at small angle of attack——with the improvement of e^N method

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Science china(physics,Mechanics & Astronomy) 2009年第1期52卷 115-123页

作者： SU CaiHong1 & ZHOU Heng1,2 1 department of Mechanics, tianjin university, tianjin 300072, china 2 Liu-Hui Center of Applied Mathematics, Nankai university and tianjin university, tianjin 300072, china department of Mechanics Tianjin University Tianjin China Liu-Hui Center of Applied Mathematics Nankai University and Tianjin University Tianjin China

The problem of transition prediction for hypersonic boundary layers over a sharp cone has been studied in this work. The Mach number of the oncoming flow is 6, the cone half-angle is 5°, and the angle of attack is 1°. The conventional e N method is used, but the transition location so obtained is obviously incorrect. The reason is that in the conventional method, only the amplifying waves are taken into account, while in fact, for different meridians the decay processes of the disturbances before they begin to grow are different. Based on our own previous work, new interpretation and essential improvement for the e N method are proposed. Not only the amplification process but also the decay process is considered. The location, where by linear stability theory, the amplitude of disturbance wave is amplified from its initial small value to 1%, is considered to be the transition location. The new result for transition prediction thus obtained is found to be fairly satisfactory. It is also indicated that for the calculation of base flow, boundary layer equations can be used for a small angle of attack. Its computational cost is much smaller than those for DNS.

关键词： angle of attack cone transition eN method

Quantum statistical entropy corresponding to cosmic horizon in five-dimensional spacetime

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Science china(physics,Mechanics & Astronomy) 2008年第2期51卷 140-146页

作者： ZHAO Ren1,2 & ZHANG ShengLi1 1 department of Applied physics, Xi’an Jiaotong university, Xi’an 710049, china 2 department of physics, Shanxi Datong university, Datong 037009, china department of Applied physics Xi’an Jiaotong University Xi’an China department of physics Shanxi Datong University Datong China

The generalized uncertainty relation is introduced to calculate the quantum statis-tical entropy corresponding to cosmic horizon. By using the new equation of state density motivated by the generalized uncertainty relation, we discuss entropies of Bose field and Fermi field on the background of five-dimensional spacetime. In our calculation, we need not introduce cutoff. There is no divergent logarithmic term in the original brick-wall method. And it is obtained that the quantum statistical en-tropy corresponding to cosmic horizon is proportional to the area of the horizon. Further it is shown that the entropy corresponding to cosmic horizon is the entropy of quantum state on the surface of horizon. The black hole's entropy is the intrinsic property of the black hole. The entropy is a quantum effect. In our calculation, by using the quantum statistical method, we obtain the partition function of Bose field and Fermi field on the background of five-dimensional spacetime. We provide a way to study the quantum statistical entropy corresponding to cosmic horizon in the higher-dimensional spacetime.

关键词： quantum statistical entropy generalized uncertainty relation high-dimensional spacetime

Laser glazing study of Co-based alloy and Ni-Nb-Cr alloy coating

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Chinese Journal of Lasers 1994年第4期B3卷 377-384页

作者： TIAN Nailiang(department of Applied physics,tianjin Institute of Science and technology, tianjin 300191,china)YANG Yongqiang(department of Mechanics, tianjin Institute of Textile Science and technology,tianjin 300160, china) tianjin Inst of Science and Technology Tianjin China

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关键词： Metallic glass cladding layer Co-based