Prediction of chaotic dynamics in sheared liquid crystalline polymers

A rheological model for rodlike polymers in the nematic liquid-crystalline phase is analyzed to characterize irregular dynamical response under pure shear flows. The model is studied with a continuation approach, and a period doubling scenario is detected. Time series generated via simulation are studied with nonlinear analysis tools to prove the existence of chaotic regimes.     

A quasi-one-dimensional model for cascade gasdynamic lasers

Applied Physics B - A quasi-one-dimensional model for cascade 16-μm gasdynamic lasers is developed. Based on this model, the effect of cavity parameters on the output pulse is studied. Also, a...     

Directed segregation in compartmentalized bi-disperse granular gas

A bi-disperse granular gas in an asymmetrical two-compartment system is studied experimentally. The presence of asymmetry within the range of our experimental parameters results in a directed segregated state and a directed clustering state. This deterministic system does not depend on the initial conditions. A modified flux model based on Lohse's flux model for bi-disperse granular gases is derived. The modified flux model explains qualitatively the experimental results.     

A sharp transition between a trivial 1D BTW model and self-organized critical rice-pile model

A one-dimensional model of a rice-pile is numerically studied for different driving mechanisms. We found that for a sufficiently large system, there is a sharp transition between the trivial behaviour of a 1D BTW model and self-organized critical (SOC) behaviour. Depending on the driving mechanism, the self-organized critical rice-pile model belongs to two different universality classes. Received 18 December 1998     

Critical Behaviors in a Stochastic Local Limited One-Dimensional Rice-Pile Model

A stochastic local limited one-dimensional rice-pile model is numerically investigated. The distributions for avalanche sizes have a clear power-law behavior and it displays a simple finite size scaling. We obtain the avalanche exponents τ_s=1.54±0.10, β_s=2.17±0.10 and τ_T=1.80±0.10, β_T=1.46±0.10. This self-organized critical model belongs to the same universality class with the Oslo rice-pile model studied by K. Christensen et al. [Phys. Rev. Lett. 77 (1996) 107], a rice-pile model studied by L.A.N. Amaral et al. [Phys. Rev. E 54 (1996) 4512], and a simple deterministic self-organized critical model studied by M.S. Vieira [Phys. Rev. E 61 (2000) 6056].     

A lattice Bhatnagar--Gross--Krook model for a class of the generalized Burgers equations

A new lattice Bhatnagar--Gross--Krook (LBGK) model for a class of the generalized Burgers equations is proposed. It is a general LBGK model for nonlinear Burgers equations with source term in arbitrary dimensional space. The linear stability of the model is also studied. The model is numerically tested for three problems in different dimensional space, and the numerical results are compared with either analytic solutions or numerical results obtained by other methods. Satisfactory results are obtained by the numerical simulations.     

Experimental study of color percolation in disordered macrosystems

The concentration dependence of the bulk resistivity for a dielectric-semiconductor-conductor three-component model system is studied. A geometrical technique for finding a percolation point in multi-component systems is suggested.     

The periodic solution to a delayed sea-air oscillator coupling model for the El Nifio-Southern Oscillation （ENSO）

A time-delay sea-air oscillator coupling model is studied. Using Mawhin＇s continuation theorem, the result on the existence of periodic solutions for the sea-air oscillator model is obtained.     

厄尔尼诺-南方涛动时滞海-气振子耦合模型

研究了一个时滞海-气振子模型.利用摄动理论和方法，得到了海-气振子模型解的渐近展开式. 关键词： 非线性 时滞 厄尔尼诺-南方涛动 海-气振子     

Coherent trapping of populations in a three-level two-mode model with multiphoton transitions

A two-mode three-level model of an atom with multiphoton transitions is studied taking into account detuning by the formalism of dressed states. Transition probabilities are calculated and quantum mechanical analogs of the Rabi frequencies are found. A possibility for the existence of coherent trapping of populations is shown in such a model and the coherent trapping states are found.     

Jamming Transition in Kinetically Constrained Models with Reflection Symmetry

A class of kinetically constrained models with reflection symmetry is proposed as an extension of the Fredrickson–Andersen model. It is proved that the proposed model on the square lattice exhibits a freezing transition at a non-trivial density. It is conjectured by numerical experiments that the known mechanism of the singular behaviors near the freezing transition in a previously studied model (spiral model) is not responsible for that in the proposed model.     

Model of new scalar bosons as the source of one-jet events at the\bar p p collider

A model involving color octet and singlet scalar bosons is studied as a possible candidate to account for the one-jet events with large missing transverse energy observed at the CERN protonantiproton collider. A distinguishing characteristic of this model, as compared to various models based on supersymmetry, is that the heavy particle being produced is assumed to be also the carrier of the missing momentum.     

电子准弹性散射宇称不守恒中的奇异夸克效应

采用相对论平均场模型，计算了１２Ｃ和４０Ｃａ的准弹性电子散射的字称不守恒不对称性Ａ．研究了核内奇异夸克成份对Ａ的影响。     

Heterogeneous precipitation on dislocations: effect of the elastic field on precipitate morphology

The shape of a coherent non-misfitting FeC precipitate formed from solute atoms that interact with a dislocation stress field was studied using kinetic Monte Carlo simulation on a rigid lattice. The system studied is a model for binary alloys with an interstitial alloying element similar to Fe–C. The interaction with the dislocation comprises both a short-range chemical term and a long-range deformation field. The effect of each of these terms on precipitate shapes for different C supersaturations was investigated. A simple analytical model is proposed to rationalize the results obtained in the atomistic simulations.     

赤道东太平洋SST的海-气振子模型

研究了一个海-气振子的非线性耦合系统的模型.利用变分迭代原理，首先构造了相应的一组泛函.其次选取其Lagrange乘子.再用广义变分迭代方法得到了海-气振子模型一组解的近似序列. 关键词： 海-气振子 非线性 耦合系统 厄尔尼诺模型     

两相流气相湍流双时间尺度耗散模型

本文提出了两相流气相湍流变动的双时间尺度耗散模型,包括气相耗散率的双时间尺度耗散模型和两相速度关联的双时间尺度各向异性耗散模型。用所提出封闭模型模拟了旋流数为0.47的气粒两相流动,发现所提出的湍流变动模型对气相脉动速度的预报结果比原有的单时间尺度模型的预报结果有明显的改进,但是颗粒尾涡的作用仍然需要进一步研究。     

Transient and Stationary Simulations for a Quantum Hydrodynamic Model

The transient and stationary characteristics of a one-dimensional quantum hydrodynamic model are comparatively studied for semiconductor charge transport in a resonant tunnelling diode. When the bias is not small, our numerical results show a deviation of the asymptotic transient solutions from the stationary ones. A dynamic instability accounts for such deviation. The stationary quantum hydrodynamic model is therefore unsuitable in general for simulating quantum devices.     

输电线非线性振动问题的同伦映射近似解

研究了一类输电线非线性振动的动力学模.利用同伦映射方法,得到了该模型的任意次精度的近似解. 关键词： 输电线 非线性振动 同伦映射 近似解