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1.
Continuous control of chaos by self-controlling feedback   总被引:126,自引:0,他引:126  
Two methods of chaos control with a small time continuous perturbation are proposed. The stabilization of unstable periodic orbits of a chaotic system is achieved either by combined feedback with the use of a specially designed external oscillator, or by delayed self-controlling feedback without using of any external force. Both methods do not require an a priori analytical knowledge of the system dynamics and are applicable to experiment. The delayed feedback control does not require any computer analyses of the system and can be particularly convenient for an experimental application.  相似文献
2.
Quantum radiation of non-stationary Kerr-Newman-de Sitter black hole   总被引:9,自引:0,他引:9  
蒋青权  杨树政  李慧玲 《中国物理》2005,14(9):1736-1744
By introducing a new tortoise coordinate transformation, we investigate the quantum thermal and non-thermal radiations of a non-stationary Kerr--Newman--de Sitter black hole. The accurate location and radiate temperature of the event horizon as well as the maximum energy of the non-thermal radiation are derived. It is shown that the radiate temperature and the maximum energy are related to not only the evaporation rate, but also the shape of the event horizon, moreover the maximum energy depends on the electromagnetic potential. Finally, we use the results to reduce the non-stationary Kerr--Newman black hole, the non-stationary Kerr black hole, the stationary Kerr--Newman--de Sitter black hole, and the static Schwarzshild black hole.  相似文献
3.
Soliton interaction under the influence of higher-order effects   总被引:6,自引:0,他引:6  
In this paper, we present exact N-soliton solution by employing simple, straightforward Darboux transformation based on the Lax pair for Hirota equation, a higher-order nonlinear Schrödinger (HNLS) equation. As examples, one- and two-soliton solutions in explicit forms are given and their properties are also analyzed. A bound solution without interaction will be theoretically predicted if one can adjust frequency shift for each soliton appropriately. Further, we obtain the approximate eigenvalues by employing two-soliton solution and discuss analytically the interaction between neighboring solitons under the influence of the higher-order effects. It is shown that the combined effects of the higher-order effects can restrain the interaction between neighboring solitons to some extent. The results are proved by directly solving HNLS equation numerically.  相似文献
4.
同伦分析法在求解非线性演化方程中的应用   总被引:5,自引:0,他引:5       下载免费PDF全文
利用同伦分析法求解了(2+1)维改进的 Zakharov-Kuznetsov方程, 得到了它的近似周期解,该解与精确解符合很好. 结果表明,同伦分析法在求解高维非线性演化方程时, 仍然是一种行之有效的方法. 同时,还对该方法进行了一定的扩展, 经过扩展后的方法能够更方便地求解更多非线性演化方程的高精度近似解析解.  相似文献
5.
二维椭圆量子台球中的谱分析   总被引:5,自引:0,他引:5       下载免费PDF全文
研究了二维椭圆台球中的量子谱和经典轨道之间的对应关系.为尝试求解没有解析波函数和本征能量又不能分离变量的体系,采用了定态展开方法(expansion method for stationary states,简称EMSS)得到尽可能精确的数值解,这是闭合轨道理论被推广到计算开轨道的情况.比较了傅里叶变换谱和经典轨道,发现量子谱的峰位置与经典轨道的长度在可分辨的范围内符合得很好,这是半经典理论为经典与量子力学的联系提供桥梁作用的又一个例子.  相似文献
6.
Electron-lattice kinetics of metals heated by ultrashort laser pulses   总被引:5,自引:0,他引:5  
We propose a kinetic model of transient nonequilibrium phenomena in metals exposed to ultrashort laser pulses when heated electrons affect the lattice through direct electron-phonon interaction. This model describes the destruction of a metal under intense laser pumping. We derive the system of equations for the metal, which consists of hot electrons and a cold lattice. Hot electrons are described with the help of the Boltzmann equation and equation of thermoconductivity. We use the equations of motion for lattice displacements with the electron force included. The lattice deformation is estimated immediately after the laser pulse up to the time of electron temperature relaxation. An estimate shows that the ablation regime can be achieved. Zh. éksp. Teor. Fiz. 115, 149–157 (January 1999) Published in English in the original Russian journal. Reproduced here with stylistic changes by the Translation Editor.  相似文献
7.
Kinetics of reversible polymerization   总被引:4,自引:0,他引:4  
This paper extends the kinetic theory of irreversible polymerization (Smoluchowski's equation) by including fragmentation effects in such a way, that the most probable (equilibrium) size distribution from the classical polymerization theories is contained in our theory as the stationary distribution. The time-dependent cluster size distributionc k (a(t)) in Flory's polymerization modelsRA f andA f RB g , expressed in terms of the extent of reaction, has the same canonical form as in equilibrium, and the time dependence of(t) is determined from a macroscopic rate equation. We show that a gelation transition may or may not occur, depending on the value of the fragmentation strength, and, in case a phase transition takes place, we give Flory- and Stockmayer-type postgel distributions.Inspec numbers: 0550, 6460, 8235, 6475.  相似文献
8.
Elastic rod model of a supercoiled DNA molecule   总被引:4,自引:0,他引:4  
We study the elastic behaviour of a supercoiled DNA molecule. The simplest model is that of a rod-like chain, involving two elastic constants, the bending and the twist rigidities. Writing this model in terms of Euler angles, we show that the corresponding Hamiltonian is singular and needs a small distance cut-off, which is a natural length scale giving the limit of validity of the model, of the order of the double-helix pitch. The rod-like chain in the presence of the cut-off is able to reproduce quantitatively the experimentally observed effects of supercoiling on the elongation-force characteristics, in the small supercoiling regime. An exact solution of the model, using both transfer matrix techniques and its mapping to a quantum mechanics problem, allows to extract, from the experimental data, the value of the twist rigidity. We also analyse the variation of the torque and the writhe-to-twist ratio versus supercoiling, showing analytically the existence of a rather sharp crossover regime which can be related to the excitation of plectoneme-like structures. Finally we study the extension fluctuations of a stretched and supercoiled DNA molecule, both at fixed torque and at fixed supercoiling angle, and we compare the theoretical predictions to some preliminary experimental data. Received 1 April 1999 and Received in final form 4 January 2000  相似文献
9.
邓雪枫  陆子凤  张彦杰  刘益春 《光子学报》2002,31(12):1501-1504
研究了甲基橙(MO)偶氮染料掺杂聚乙烯醇(PVA)薄膜的光致双折射和全息光存储特性.利用YAG激光二倍频(532nm)作为写入光,He-Ne激光(632.8nm)作为读出光,考察了不同染料浓度薄膜的光致双折射,探讨了光致双折射和泵浦光功率的关系,并实现了全息光存储.阐明了MO/PVA光存储的物理机制.  相似文献
10.
Infinite conformal symmetry of critical fluctuations in two dimensions   总被引:3,自引:0,他引:3  
We study the massless quantum field theories describing the critical points in two dimensional statistical systems. These theories are invariant with respect to the infinite dimensional group of conformal (analytic) transformations. It is shown that the local fields forming the operator algebra can be classified according to the irreducible representations of the Virasoro algebra. Exactly solvable theories associated with degenerate representations are analized. In these theories the anomalous dimensions are known exactly and the correlation functions satisfy the system of linear differential equations.Professor A. B. Zamolodchikov was unable to attend the conference to present this invited paper personally.  相似文献
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