极点配置控制器设计的行为化方法

从互连控制的角度对系统的极点配置问题进行了研究，设计了一类（正则）极点配置控制器，并揭示了行为化方法下的互连控制与经典反馈控制之间的关系．

组合系统的行为化方法

在行为框架下研究线性微分组合系统的建模问题 .建立了 n个子系统串、并联组合系统的行为化模型 ,给出了其能控性、能观性的判别条件 .分析过程表明用行为化方法对组合系统的研究有着比传统方法更便捷、适用的模型类更广等优点 .

A User Participation Behavior Prediction Model of Social Hotspots Based on Influence and Markov Random Field

Hotspot topic trends can be captured by analyzing user attributes and historical behavior in social network. In this paper, we propose a user participation behavior prediction model for social hotspots, based on user behavior and relationship data, to predict user participation behavior and topic development trends. Firstly, for the complex factors of user behavior, three dynamic influence factor functions are defined, including individual, peer and community influence. These functions take timeliness into account using a time discretization method. Secondly, to determine laws of individual behavior and group behavior within a social topic, a hotspot user participation behavior prediction model is proposed and associated with the basic concepts of randora field and Markov property in information diffusion. The experimental results show that the model can not only dynamically predict the individual behavior, but also grasp the development trends of topics.

Corrosion behavior of hafnium in anhydrous isopropanol and acetonitrile solutions containing bromide ions

The corrosion behaviors of hafnium in Et4NBr isopropanol and acetonitrile(ACN)solutions were investigated usingelectrochemical measurements,ICP-AES and SEM techniques.Results revealed that the open circuit potential gets more positive dueto the increased passivity of the surface oxide film with increasing immersion time until it reaches a steady state value.Thepotentiodynamic anodic polarization curves did not exhibit an active dissolution region near corrosion potential due to the presenceof an oxide film on the electrode surface,which was followed by pitting corrosion.SEM images confirmed the existence of pits onthe electrode surface.Cyclic voltammetry and galvanostatic measurements allowed the pitting potential(φpit)and the repassivationpotential(φp)to be determined.φpit increased with increasing potential scanning rate but decreased with increasing temperature,Br-concentration and ACN concentration.The impedance spectra showed that the resistances of the solution and charge transferdecreased with the increase of ACN concentration.

Elastic Behavior of Polymer Chains

The elastic behavior of the polymer chain was investigated in a three-dimensional off-lattice model. We sample more than 109 conformations of each kind of polymer chain by using a Monte Carlo algorithm, then analyze them with the non-Gaussian theory of rubberlike elasticity, and end with a statistical study. Through observing the effect of the chain flexibility and the stretching ratio on the mean-square end-to-end distance, the average energy, the average Helmholtz free energy, the elastic force, the contribution of energy to the elastic force, and the entropy contribution to elastic force of the polymer chain, we find that a rigid polymer chain is much easier to stretch than a flexible polymer chain. Also, a rigid polymer chain will become difficult to stretch only at a quite high stretching ratio because of the effect of the entropy contribution. These results of our simulation calculation may explain some of the macroscopic phenomena of polymer and biomacromolecular elasticity.

GLOBAL ASYMPTOTIC STABILITY FOR A TWO-SPECIES DISCRETE RATIO-DEPENDENT PREDATOR-PREY SYSTEM

The dynamical behaviors of a two-species discrete ratio-dependent predator-prey sys- tem are considered. Some sufficient conditions for the local stability of the equilibria is obtained by using the linearization method. Further, we also obtain a new sufficient condition to ensure that the positive equilibrium is globally asymptotically stable by using an iteration scheme and the comparison principle of difference equations, which generalizes what paper [G. Chen, Z. Teng and Z. Hu, Analysis of stability for a discrete ratio-dependent predator-prey system, Indian J. Pure Appl. Math. 42（1） （2011） 1-26] has done. The method given in this paper is new and very resultful comparing with papers [H. F. Huo and W. T. Li, Existence and global stability of periodic solutions of a discrete predator--prey system with delays, Appl. Math. Comput. 153 （2004） 337-351; X. Liao, S. Zhou and Y. Chen, On permanence and global stability in a general Gilpin- Ayala competition predator prey discrete system, Appl. Math. Comput. 190 （2007） 500-509] and it can also be applied to study the global asymptotic stability for general multiple species discrete population systems. At the end of this paper, we present an open question.

Sodium dodecyl sulfate sensitized electrochemical method for subnanomole level determination of ortho-phenylphenol at a novel disposable electrode

The electrochemical behavior of ortho-phenylphenol （OPP） at a disposable electrode （an improved wax-impregnated graphite electrode） in the presence of sodium dodecyl sulfate （SDS） was studied for the first time. The results demonstrated that the electrocatalytic oxidation process of OPP was accompanied with two-charge-two-proton transference. The electronic transmission coefficient （a） and diffusion coefficient （DR） for OPP were calculated to be 0.8126 and 3.61× 10^-2 cm2/s, respectively. The electrochemical signal was apparently improved by SDS at the disposable electrode and the oxidative peaks current was proportional to the concentration of OPP over the range from 1.0 ×10^-9 to 4.0 × 10^-6 mol/L with the detection limit of 8.7× 10^-10 mol/L. This novel and highly sensitive method can be successfully applied to detect OPP in the orange rind sample.