Locating the equilibrium points of a predator–prey model by means of affine state feedback

A predator–prey model with prey-dependent functional response is considered. The set of all points in the positive quadrant of the state plane that can be made equilibrium points by means of an affine state-feedback control law is determined, and the values of the control parameters ensuring the desired equilibria are provided. It is shown how the asymptotic stability of the equilibrium points depends on simple geometric conditions. The problem of stabilizing unstable equilibrium points is also briefly discussed.     

论20世纪30年代后期国际金融体系转型——1936年美英法《三方货币稳定协议》及其启示

在当前国际金融体系因全球遭遇70年来最严重的金融和经济危机而面临巨大挑战之时,尤其是在当前国际金融协调机制正从G8向G20转化的过程中,深入研究1929年-1933年世界经济大危机之后,美欧主要金融大国的货币政策协调历史很有现实意义.1936年美英法<三方货币稳定协议>就是在30年代世界经济大危机之后达成的具有明显国际金融体系转型含义的协议.该协议及其附属协议中规定的国际汇兑安排将美元的黄金价格作为买卖通货的标准,这种安排实际上是一种非正式的"美元本位",它表明英国和法国开始接受美国主导的新的国际金融协调机制,显示了美元的"准霸权"地位,也为二战后国际金融的布雷顿森林体系作了铺垫.     

共振论与有机化合物的酸碱度

对于有机化合物的酸碱度问题 ,作者从共振论的观点出发 ,应用共振稳定作用原理 ,对某些有机物的酸碱性进行了分析和判断。     

木纳格葡萄籽中原花青素提取及稳定性的研究

主要研究了pH值、温度、金属离子及其它食品添加剂对原花青素稳定性的影响,实验结果表明,原花青素pH=2～6时降解缓慢,热稳定性较好;但在60℃以上温度时原花青素会受到一定影响;Cu2^2＋、Pb^2＋、Mn^2＋对原花青素影响较小,Fe^3＋和Sn^2＋对原花青素有破坏作用。     

Decentralized impulsive control for a class of uncertain interconnected systems

INTRODUCTIONWiththedevelopmentofscienceandtech-nology,thestructuresofcontrolsystemsaregettingmoreandmorecomplicated.Thiskindofsystemhasthecharacteristicoflargedimension,andin-terconnectionamongsubsystems.Generally,thiskindofsystemiscalledinterconnectedlargesystem.Thestudyofinterconnectedsystemsismotivatedbyquiteanumberofpracticalapplicationsrangingfrompowernetworks,transportation,aerospace,economics,management,andsoon.Thestrategiestocontrolinterconnectedsystemsaredividedintotwokinds:centr…     

污水资源化稳定塘中凤眼莲吸收富集铬规律及除铬效能

本文研究了铬在凤眼莲为资源化水生植物的稳定塘中的行为规律,指出凤眼莲提高稳定塘除铬效果的主要原因是它对水体水力学沉降条件的改善。     

Immobilization of heavy metals in sludge using phosphoric acid and monobasic calcium phosphate

The purpose of this research is to investigate the potential of pre-treatment with phosphoric acid(PA) and monobasic calcium phosphate(MCP) for the stabilization of heavy metals in sludge and its bottom ash.The tannery sludge samples were collected in Wenzhou,China and heavily contaminated with heavy metals,such as Pb,Cr and so on.The samples were pre-treated with PA or MCP.Then XRD and TCLP tests were adopted as the evaluating methods to characterize the Pb,Cr,Cu,Zn and Cd immobilization in the pre-treated sludge and its bottom ash.The results showed that this treatment effectively immobilized Pb and Cd in the sludge,lightly stabilized the metal Cu,and adversely,enhanced the leachability of Zn.After incineration at 900℃,Pb and Cr in the bottom ash of pre-treated sludge were significantly stabilized due to the formation of their highly thermostable phosphates and pyromorphite-like minerals during the incineration process.However,an increase of Cu and Zn solubility was observed which might be attributable to the acidification of sludge due to the addition of PA or MCP.     

高职院校学生专业思想引导初探--从专业角度谈班主任工作重心

高职院校学生是一个具有特殊性的群体。高职院校学生三年的高校生活，可以概括为三个时期：适应期、稳定期、成熟期。基本上以每一学年为一个时期，每个时期学生的特点不同，班主任的工作重心也应有所不同。     

Decentralized impulsive control for a class of uncertain interconnected systems

A great deal of stabilization criteria has been obtained from study of stabilizing interconnected systems. The results obtained are usually based on continuous systems by state feedback. In this paper, decentralized impulsive control is presented to stabilize a class of uncertain interconnected systems based on Lyapunov theory. The system under consideration involves parameter uncertainties and unknown nonlinear interactions among subsystems. Some new criteria of stabilization under impulsive control are established. Two numerical examples are offered to prove the effectiveness and practicality of the proposed method.     

广义离散时变系统的镇定

对于一类广义离散时变系统,通过Lyapunov方程的建立,给出了系统因果且渐近稳定的充分必要条件,基于这一结果,利用对应的Riccati方程进一步研究了系统的能稳定性问题,给出了系统能稳定的充分必要条件.最后,举例说明了所得结果的正确性.