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991.
Yong-Hong Lan Liang-Liang Wang Cai-Xue Chen Ding Lei 《Journal of Optimization Theory and Applications》2017,174(1):197-209
This paper presents an optimal sliding mode output tracking control scheme for a class of fractional-order uncertain systems. Firstly, an augmented fractional-order system, composed of the original system and the external system, is constructed to transform the optimal output tracking issue into the design problem of linear quadratic regulator. The optimal tracking control problem for the nominal augmented fractional-order system is then studied. Secondly, the fractional-integral sliding mode controller is introduced to robustify the augmented fractional-order system, which satisfy the matching conditions. As a result, the original system output can track the external system output trajectory effectively even the uncertainties exist. Finally, the developed design techniques are applied to the tracking control of fractional-order permanent magnet synchronous motor. The simulation results demonstrate the validity of this approach. 相似文献
992.
Chunxiao Ding Yun Sun Yuanguo Zhu 《Mathematical Methods in the Applied Sciences》2017,40(14):5079-5094
A new mathematical model included an exposed compartment is established in consideration of incubation period of schistosoma in human body. The basic reproduction number is calculated to illustrate the threshold of disease outbreak. The existence of the disease free equilibrium and the endemic equilibrium are proved. Studies about stability behaviors of the model are exploited. Moreover, control measure assessments are investigated in order to seek out effective control interventions for anti‐schistosomiasis. Then, the corresponding optimal control problem according to the model is presented and solved. Theoretical analyses and numerical simulations induce several prevention and control strategies for anti‐schistosomiasis. At last, a discussion is provided about our results and further work. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
993.
利用分子动力学计算机模拟方法研究了稠密流体中双原子分子的振动弛豫问题,证实了双原产分子的振动弛豫速率随着其非谐性的增大而加快,同时,其速率也随其质量因子的变大而加速。 相似文献
994.
弥散型核燃料元件热应力的计算模拟 总被引:2,自引:0,他引:2
针对弥散型燃料板的具体形状,选择了一种能够反映其实际变形特征的三维代表性体积单元作为研究对象;利用有限元法对其热力耦合行为进行了弹塑性分析,研究了热应力在燃料和基体中的分布特征. 相似文献
995.
GENERAL SOLUTION OF PLANE PROBLEM OF PIEZOELECTRIC MEDIA EXPRESSED BY "HARMONIC FUNCTIONS 总被引:4,自引:0,他引:4
I.IntroductionBecauseofthecouplingcharacteristicbetweenthemechanicaldeformationandthee1ectricaleffect,piezoelectricmaterialshavebeenwidelyusedintransducersandsmartstructures.Moreandmoreattentionshavebeenpaidonsuchmaterials,andgreatadvanceshavebeenmadeinva… 相似文献
996.
Energy relaxation processes initiated by sudden heating of the vibrational degree of freedom were studied with molecular dynamical
method. A unit cell of bee structure containing 128 diatomic molecules with periodic boundary conditions was considered. Compound
Morse potential was assumed as the atom-atom interactions. It was found that the logarithra of the equilibration time depends
linearly upon a factorf
21 which is proportional to the frequency ratio of the intra- and inter-molecular vibrations.
The project is supported by the National Natural Science Foundation of China. 相似文献
997.
用三维光弹法测定了轴表面横向半椭圆裂纹的应力强度因子,并分析计算了应力强度因子修正系数,结果表明,应力强度因子的分布型式对加载条件和裂纹几何不敏感;修正系数对裂纹深度呈现对称分布趋势,仅取决于裂纹几何参数。 相似文献
998.
心脏与血管的相互影响 总被引:2,自引:0,他引:2
心脏与血管的相互影响早就引起生理学家们的兴趣,但其在临床医学上的广泛应用则是近几年的事.这主要归功于两大生物力学成就,一是应甩泵功能曲线和时变弹性元描述心脏功能,另一是应用输入阻抗来描述血管功能.本文系统地总结和评述了20多年来国际上关于心脏与血管相互影响的研究发展概况. 相似文献
999.
Jianhua?XieEmail author Wangcai?Ding E. H.?Dowell L. N.?Virgin 《Acta Mechanica Sinica》2005,21(4):402-410
This paper addresses the problem of Hopf-flip bifurcation of high dimensional maps. Using the center manifold theorem, we obtain a three dimensional reduced map through the projection technique. The reduced map is further transformed into its normal form whose coefficients are determined by that of the original system. The dynamics of the map near the Hopf-flip bifurcation point is approximated by a so called ‘‘time-2τ2 map’’ of a planar autonomous differential equation. It is shown that high dimensional maps may result in cycles of period two, tori T1 (Hopf invariant circles), tori 2T1 and tori 2T2 depending both on how the critical eigenvalues pass the unit circle and on the signs of resonant terms’ coefficients. A two-degree-of-freedom vibro-impact system is given as an example to show how the procedure of this paper works. It reveals that through Hopf-flip bifurcations, periodic motions may lead directly to different types of motion, such as subharmonic motions, quasi-periodic motions, motions on high dimensional tori and even to chaotic motions depending both on change in direction of the parameter vector and on the nonlinear terms of the first three orders.The project supported by the National Natural Science Foundation of China (10472096)The English text was polished by Ron Marshall. 相似文献
1000.