振动环境中非线性运输包装系统的混沌响应

对振动流通环境中非线性运输包装系统进行了仿真,并通过对系统运动的时间历程、相图、Poincare映射及功率谱等的分析,讨论了在确定性振动环境中系统的混沌动力学行为及其危害.

非线性TP的PSO求解

运输问题自提出后,人们因其在各个领域的广泛应用进行了大量研究。尤其是线型运输问题,已经设计出了多种有效解法,但它们均不能直接处理非线性运输问题。本文在经典粒子群算法PSO的基础上设计了新算法PSO-NLTP,它通过改进PSO的粒子飞行速度和飞行位置更新方程,及设计出负修复算子,既满足TP的约束条件,又扩大了搜索空间。针对经典PSO算法容易在局部最优解过早停止搜索的不足,我们添加了自适应的变异算子,以防止PSO-NLTP过早停止搜索。通过仿真实例证明,与遗传算法GA-NLTP和带惩罚策略的EP进行比较,PSO-NLTP能在较短的时间内找到更优解,结果验证了新算法的有效性。

大规模定制中顺序间歇过程批调度研究

间歇过程生产在大规模定制中占有重要地位,顺序间歇过程是一种常见的间歇过程,现有研究将顺序间歇过程调度分为需求分批与批次调度两步求解过程,忽略了它们之间相互制约、不可分割的内在联系,为了校正这种人为断裂,以获得真正意义上的最优化调度,提出了顺序间歇过程批调度问题.用α | β | γ法对顺序间歇过程批调度问题进行描述,给出了基本的作业属性、加工环境和批调度性能指标.针对基于完成时间的性能指标,提出了两个并行机间歇过程批调度问题,在分析了几个有用性质后,将两个问题分别等价为固定费用运输问题和非线性运输问题.

电力远距离输送分配优化设计模型分析

以某供电公司在电力远距离输送过程中需要解决的电力输送分配优化设计为例,为国家电网建设中电力远距离输送分配优化设计问题建立有效模型和求解方法。将电力输送分配优化设计问题归结为非线性固定费用运输问题,建立了相应的非线性规划数学模型,并利用Lingo软件求解。求解结果分析表明:电力远距离输送过程中输电线路电压在320 kV时供电公司营运总费用可达到最优,并计算出供电公司当输电线路电压为320 kV时各发电企业向所有用电城市分配电力时实际输送的电流值。

A Model of Car-Following with Adaptive Headway

The performances of a well-known GHR car-following model was investigated by using numerical simulations in describing the acceleration and deceleration process induced by the motion of a leading car. It is shown that in GHR model vehicle is allowed to run arbitrarily close together if their speed are identical,and it waves aside even though the separation is larger than its desired distance. Based on these investigations, a modified GHR model which features a new nonlinear term which attempts to adjust the inter-vehicle spacing to a certain desired value was proposed accordingly to overcome these deficiencies. In addition, the analysis of the additive nonlinear term and steady-state flow of the new model were studied to prove its rationality.

Nonlinear Mechanism of Bed Load Transport

From the group movement of the bed load within the bottom layer,details of the nonlinear dynamic characteristics of bed load movement are discussed in this paper.Whether the sediment is initiated into motion corresponds to whether the constant term in the equation is equal to zero.If constant term is zero and no dispersive force is considered,the equation represents the traditional Shields initiation curve,and if constant term is zero without the dispersive force being considered,then a new Shields curve which is much lower than the traditional one is got.The fixed point of the equation corresponds to the equilibrium sediment transport of bed load.In the mutation analysis,we have found that the inflection point is the demarcation point of breaking.In theory,the breaking point corresponds to the dividing boundary line,across which the bed form changes from flat bed to sand ripple or sand dune.Compared with the experimental data of Chatou Hydraulic Lab in France,the conclusions are verified.

Influence of wave and current on deep-sea mining transporting system

As a solution to the breaking of pipeline under high axial force,carbon fiber composite pipe with low density and high intensity is applied to deep-sea mining transporting system.Based on the fact that the transporting pipe is under the forces of gravity,inner liquid,buoyancy as well as hydrodynamic force,geometric nonlinear finite element theory has been applied to analyzing the transporting system.Conclusions can be drawn as follows.Under the interaction of waves and currents,node forces FX and FZ acted by the transporting pipe on the mining vehicle are less than 2 kN,which indicates that waves and currents have little influence on the spatial shape of the transporting pipe and the mining vehicle movement.On the other hand,the horizontal force acting on the mining ship could be as large as 106 830 N,which has great influence on the mining system.

Thermal Transport in One-Dimensional FPU-FK Lattices

Thermal transport in the FPU model with Kutta algorithm. The heat flux, local temperature profile, that temperature gradient scales behave as N-1 linearly. FK on-site potential is studied by using fourth-order Runge- and heat conductivity axe simulated and analyzed. It is found The divergence of heat conductivity ~ with system size N is in term of κ ∝ N^α with α = 0.44. It is shown that thermal transport is mainly dependent on the FPU nonlinear and the FK interactions.

重力波对中层顶区O_3及OH分布的影响

利用考虑了光化-动力耦合的重力波模式就重力波对大气化学成分分布的影响进行了计算, 着重研究了重力波通过非线性化学反应对大气化学成分分布的影响这一新的机制, 以O3和OH为例进行了计算. 研究表明, 重力波在传播过程中主要通过非线性化学反应引起中层顶区大气化学成分分布的变化, 其贡献可以超过湍流扩散和重力波引起的非线性输运.

Compound Method of Solving Logistics Routes Allocation

The logistics routes allocation discusses optimal routing from origin to destination through distribution center （DC） on condition that both transport and distribution cost should be taken into account. The problem can be solved by the iterative non-linear programming （INLP）, in which the transport cost and distribution cost are assumed to be linear and non-linear, respectively. The method works well in most situations. However, when the distribution cost predominates in the total cost, the method falls, and the solution given by the method is not a global minimum but a local minimum. Further study reveals that the INLP method is still a kind of transport routing method like vehicle routing problem （VRP）, and the failure of the method must happen when the distribution cost is a major one. On such a condition, further computation on other extreme points, which physically means forcing all routes to pass through one DC one by one, should be carried out. By comparing values on these extreme points, the global optimal solution can be got. The method has both theoretical and practical meaning. In theoretical field, it might force us to seek new method; in practice, it reminds us to do such kind of check when the transport distance is short and warehousing work is major that often happens in local consolidation center or de-vanning center.

Physiological Transportation of Casson Fluid in a Plumb Duct

This paper is devoted to a study of the peristaltic motion of a Casson fluid of a non-Newtonian fluid accompanied in a horizontai tube.To characterize the non-Newtonian fluid behavior,we have considered the Casson fluid model.Suitable similarity transformations are utilized to transform the governing partial differential momentum into the non-linear ordinary differential equations.Exact analytical solutions of these equations are obtained and are the properties of velocity,pressure and profiles are then studied graphically.

Peristaltic transport of pseudoplastic fluid in a curved channel with wall properties and slip conditions

Effects of wall properties and slip condition on the peristaltic flow of an incompressible pseudoplastic fluid in a curved channel are studied. Series solution of the governing problem is obtained after applying long wavelength and low Reynolds number approximations. The results are validated with the numerical solutions through the built-in routine for solving nonlinear boundary value problems via software Mathematica. The variations of different parameters on axial velocity are carefully analyzed. Behaviors of embedding parameters on the dimensionless stream function are also discussed. It is noted that the axial velocity and size of trapped bolus increases with an increase in slip parameter. It is also observed that the profiles of axial velocity are not symmetric about the central line of the curved channel which is different from the case of planar channel.

The Moser-Trudinger-Onofri Inequality

This paper is devoted to results on the Moser-Trudinger-Onofri inequality, or the Onofri inequality for brevity. In dimension two this inequality plays a role similar to that of the Sobolev inequality in higher dimensions. After justifying this statement by recovering the Onofri inequality through various limiting procedures and after reviewing some known results, the authors state several elementary remarks.Various new results are also proved in this paper. A proof of the inequality is given by using mass transportation methods(in the radial case), consistently with similar results for Sobolev inequalities. The authors investigate how duality can be used to improve the Onofri inequality, in connection with the logarithmic Hardy-Littlewood-Sobolev inequality.In the framework of fast diffusion equations, it is established that the inequality is an entropy-entropy production inequality, which provides an integral remainder term. Finally,a proof of the inequality based on rigidity methods is given and a related nonlinear flow is introduced.

Negative differential resistance in a molecular junction of carbon nanotube and benzene

We propose a novel molecular junction with single-walled carbon nanotubes as electrodes bridged by a benzene molecule, in which the electrodes are saturated by different terminations (C-, H- and N-). It is found that the different terminations at the carbon nanotube ends strongly affect the electronic transport properties of the junction. The current-voltage (I-V) curve of the N-terminated carbon nanotube junction shows a more striking nonlinear feature than that of the C- and H-terminated junctions at small bias. Moreover, the negative differential resistance behaviors can be observed significantly in the N-terminated carbon nanotube junction, whereas not in the other two cases.