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1.
The robust stabilization problem for a class of uncertain linear time-delay systems containing sector saturating actuator
is considered in this paper. The uncertain time-delay systems under consideration are described by state differential equations
with time-varying unknown-but-bounded uncertain parameters and delayed state. The delay is assumed to be constant bounded
but unknown. The new criterion of delay-dependent robust stabilizability for uncertain time-delay systems is presented and
the corresponding robust memoryless state feedback controller is derived in terms of the solutions of several linear matrix
inequalities (LMIs). Numerical example is presented to illustrate the obtained results.
Project supported by the Natural Science Key Foundation of China (NSFC: 69934030) and the Excellent (Youth) Teacher for Teaching
and Research Award Foundation in Institutions of China. 相似文献
2.
A new algorithm is presented that generates developable Bézier surfaces through a Bézier curve called a directrix. The algorithm
is based on differential geometry theory on necessary and sufficient conditions for a surface which is developable, and on
degree evaluation formula for parameter curves and linear independence for Bernstein basis. No nonlinear characteristic equations
have to be solved. Moreover the vertex for a cone and the edge of regression for a tangent surface can be obtained easily.
Aumann’s algorithm for developable surfaces is a special case of this paper.
Project supported by the National Basic Research Program (973) of China (No. 2004CB719400), the National Natural Science Foundation
of China (Nos. 60373033 and 60333010) and the National Natural Science Foundation for Innovative Research Groups (No. 60021201),
China 相似文献
3.
In this paper, the axisymmetric general solutions of transversely isotropic magnetoelectroelastic media are expressed with
four harmonic displacement functions at first. Then, based on the solutions, the analytical three-dimensional solutions are
provided for a simply supported magnetoelectroelastic circular plate subjected to uniform loads. Finally, the example of circular
plate is presented.
Project supported by the National Natural Science Foundation of China (No. 10172075) and Ningbo Natural Science Foundation
for Young Scientist (No. 02J20102-13) 相似文献
4.
This paper discusses the application of the boundary contour method for resolving plate bending problems. The exploitation
of the integrand divergence free property of the plate bending boundary integral equation based on the Kirchhoff hypothesis
and a very useful application of Stokes' Theorem are presented to convert surface integrals on boundary elements to the computation
of bending potential functions on the discretized boundary points, even for curved surface elements of arbitrary shape. Singularity
and treatment of the discontinued corner point are not needed at all. The evaluation of the physics variant at internal points
is also shown in this article. Numerical results are presented for some plate bending problems and compared against analytical
and previous solutions.
Project(No: ZE0208) supported by the National Science Foundation of Zhejiang Province, China 相似文献
5.
General solutions for coupled three dimensional equations of piezoelectric media were used in this work to obtain some analytical
solutions for free vibration of piezoelectric annular plates. These solutions not only satisfy the governing equations at
every point in the concerned region but also satisfy the prescribed boundary conditions at every point on the boundaries.
Therefore, they are three-dimensional exact. Numerical results are finally tabulated.
Project (No. 10002016) supported by the National Natural Science Foundation of China 相似文献
6.
Pure bending of simply supported circular plate of transversely isotropic functionally graded material 总被引：3，自引：0，他引：3
LI Xiang-yu DING Hao-jiang CHEN Wei-qiu 《浙江大学学报(A卷英文版)》2006,7(8):1324-1328
INTRODUCTION In recent years, functionally graded materials (FGMs) have attracted more and more attention. Due to their continuously varying material properties in space on the macroscopic scale, FGMs, therefore, are usually superior to conventional fiber-matrix materi-als in mechanical behavior, especially for perform-ance under thermal loading. Now FGMs have been widely used in various fields including electronics, chemistry, optics, biomedicine, etc. Heretofore, volumes of literatu… 相似文献
7.
n-soliton-like solutions of three non-isospectral equations, the non-isospectral mKdV equation, the non-isospectral sine-Gordon equation and the non-isospeetral nonlinear Schroedinger equation were obtained by using the Hirota method. 相似文献
8.
Broadband phase shifters are mostly proposed and fabricated based on the scheme proposed by Shiffman, which uses a coupled line with far ends connected together and a uniform transmission line to give a differential phase shift. Based on the unique dispersion property of the composite right/left-handed (CRLH) metamaterial structure, a new configuration is presented in this paper for fabricating the broadband differential phase shifter, which employs a novel CRLH metamaterial structure as one of the differential phase-shift arms, instead of the conventional coupled line. The new circuit can achieve a phase shift of 90° in an operational bandwidth as broad as one octave and its phase deviations are quite small. An original design of the novel broadband phase shifter is presented, in which the artificial CRLH structure was implemented by microstrip quasi-lumped elements. Both the simulated and measured results of the 90° broadband differential phase shifter are presented. 相似文献
9.
For the non-conservative holonomic Hamiltonian systems in phase space, the definition and criteria of the form invariance of the generalized Hamilton canonical equations were given. The relations among the form invariance, Noether symmetry and Lie symmetry were studied. The theory of the form invariance for the conservative holonomical systems was worked out. An example was given to illustrate the results. 相似文献
10.
The bilinear Baecklund transformation (BT) provides a means of finding multisoliton solutions of some non-linear evolution equations, where Hirota‘s technique is used. In this paper, the bilinear BT for Toda lattice was modified and then some novel solutions of the Toda lattice was constructed through the modified BT. 相似文献
11.
FANG You-tong YAO Ying-ying 《浙江大学学报(A卷英文版)》2007,8(3):412-415
In this paper, a modified transient finite element (FE) algorithm for the performance analysis of magnetically levitated vehicles of electromagnetic type is presented. The algorithm incorporates the external power system and vehicle’s movement equations into FE model of transient magnetic field computation directly. Sliding interface between stationary and moving region is used during the transient analysis. The periodic boundaries are implemented in an easy way to reduce the computation scale. It is proved that this method can be used for both electro-motional static and dynamic cases. The test of a transformer and an EMS-Maglev system reveals that the method generates reasonable results at very low computational costs comparing with the transient FE analysis. 相似文献
12.
INTRODUCTION High data rate and high quality multimedia ser- vices are required in beyond third generation (B3G) and fourth generation (4G) mobile communications. Space-time coding scheme has been proposed (Tarokh et al., 1998; 1999) to achieve higher capacity and data rate. So far, most research on space-time coding assumed that accurate channel estimations are available at the receivers. However, accurate channel estimation is difficult and too many training symbols are required in a r… 相似文献
13.
Thermal-mechanical behavior of functionally graded thick plates, with one pair of opposite edges simply supported, is investigated based on 3D thermoelasticity. As for the arbitrary boundary conditions, a semi-analytical solution is presented via a hybrid approach combining the state space method and the technique of differential quadrature. The temperature field in the plate is determined according to the steady-state 3D thermal conduction. The Mori-Tanaka method with a power-law volume fraction profile is used to predict the effective material properties including the bulk and shear moduli, while the effective coefficient of thermal expansion and the thermal conductivity are estimated using other micromechanics-based models. To facilitate the implementation of state space analysis through the thickness direction, the approximate laminate model is employed to reduce the inhomogeneous plate into a homogeneous laminate that delivers a state equation with constant coefficients. The present solutions are validated by comparisons with the exact ones for both thin and thick plates. Effects of gradient indices, volume fraction of ceramics, and boundary conditions on the thermomechanical behavior of functionally graded plates are discussed. 相似文献
14.
Stabilization for a class of second-order switched systems with saturation constrains 总被引：1，自引：0，他引：1
This paper proposes a global stabilization method for a class of planar switched systems with input saturation constrains
by using a state feedback and switching strategy. This method is proved to be effective by analyzing the characteristics of
the trajectory of second-order linear systems with input saturation.
Project supported by the China Postdoctoral Science Foundation (Grant No.20070420643), the National Natural Science Foundation
of China (Grant No.60774059), and the Innovation Program of the Shanghai Municipal Science and Technology Commission (Grant
No.08DZ2272400) 相似文献
15.
A closed-loop algorithm to detect human face using color information and reinforcement learning is presented in this paper.
By using a skin-color selector, the regions with color “like” that of human skin are selected as candidates for human face.
In the next stage, the candidates are matched with a face model and given an evaluation of the match degree by the matching
module. And if the evaluation of the match result is too low, a reinforcement learning stage will start to search the best
parameters of the skin-color selector. It has been tested using many photos of various ethnic groups under various lighting
conditions, such as different light source, high light and shadow. And the experiment result proved that this algorithm is
robust to the varying lighting conditions and personal conditions.
Project supported by the National Natural Science Foundation of China (No. 60105003) and Zhejiang Provincial Natural Science
Foundation of China (No. 600025). 相似文献
16.
The symplectic approach proposed and developed by Zhong et al. in 1990s for elasticity problems is a rational analytical method, in which ample experience is not needed as in the conventional semi-inverse method. In the symplectic space, elasticity problems can be solved using the method of separation of variables along with the eigenfunction expansion technique, as in traditional Fourier analysis. The eigensolutions include those corresponding to zero and nonzero eigenvalues, The latter group can be further divided into α- and β-sets. This paper reformulates the form of β-set eigensolutions to achieve the stability of numerical calculation, which is very important to obtain accurate results within the symplectic frame. An example is finally given and numerical results are compared and discussed. 相似文献
17.
The authors give the solution to the problem of one-dimensional consolidation of double-layered ground with the use of the
differential quadrature method. Case studies showed that the computational results for pore-water pressure in soil layer agreed
with those of analytical solution; and that in the computational results for the interface of soil layer also agreed with
those of the analytical solution except for the small discrepancies during shortly after the start of computation. The advantages
of the solution presented in this paper are that compared with the analytical solution, it avoids the cumbersome work in solving
the transcendental equation for eigenvalues, and in the case of the Laplace transform solution, it can resolve the precision
problem in the numerical solution of long time inverse Laplace transform. Because of the matrix form of the solution in this
paper, it is convenient for formulating computational program for engineering practice. The formulas for calculating double-layered
ground consolidation may be easily extended to the case of multi-layered soils.
Project (No. RC9609) supported by the Zhejiang Provincial Natural Science Foundation of China 相似文献
18.
The elastic-plastic singular stress field near an interface edge of bounded linear hardening material is substantially as
same as that of bonded elastic materials whose Young's modulus and Poisson ratio are substituted by equivalent values, respectively.
Further investigation by the elasto-plastic boundary element method (BEM) on the stress field near the interface edge showed
that the stress field there can be divided into three regions: the domain region of the elastic-plastic singular stress field,
the transitional region and the elastic region. The domain region of the elastic-plastic singular stress becomes larger with
the increasing of the linear hardening coefficient. When the linear hardening coefficient decreases to a certain value, the
effective stress in most of the yield zone equals approximately the yield stress. The stress distribution in the elastic region
under small-scale yielding condition was also investigated.
Project (No. 19972060) supported by the National Natural Science Foundation of China. 相似文献
19.
Samarium and a catalytic amount of iodine were used to obtain functionalized cyclopentenes by reductive dimerization followed
by intramolecular cyclization of 1,1-dicyanoalkenes under mild conditions.
Preject (No. 20072033) supported by the National Natural Science Foundation of China, and Zhejiang Provincial Natural Science
Foundation of China 相似文献
20.
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