摘要:

The Stoner‐Wohlfarth model and the chain‐of‐spheres fanning model are used to calculate temperature dependence of the coercivity of acicular single‐domain particles by taking thermal effect into consideration. Coercivity of the particles is evaluated by summing up the contributions of shape anisotropy, magnetocrystalline anisotropy and magnetostrictive anisotropy. The coercivities of randomly assembled Fe3O4particles above the transition point (119°K) and below room temperature are calculated and compared with the published experimental data.

ISSN:0253-3839    

DOI:10.1080/02533839.1989.9677187

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The extreme value problem is related to the first excursion problem in random vibration analysis. In the present paper, Gumbel's order statistics and the asymptotic theory of statistical extremes are applied directly to the peak distribution function of a stationary random process in order to find the probability distribution of the extremal value within a certain time interval. The extreme value distribution of a random process obtained from this approach is compared with results from some classical methods. It is concluded that the present approach can be applied not only to a narrow‐band process but also to a wide‐band process for which the classical methods usually use several approximations to find the approximate results. The second part of this paper deals with the first excursion probability. A semi‐empirical formula based on results of the first part and a correlation time consideration are proposed. Three examples, which include a narrow‐band process, a wide‐band process and a uniformly modulated process, are studied. The results are compared favorably with either simulation results or those obtained from other methods.

ISSN:0253-3839    

DOI:10.1080/02533839.1989.9677188

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

In this paper, a model reduction method based on expanding the matrix fraction description (MFD) of a multi‐input multi‐output (MIMO) discrete system into bilinear block Routh canonical continued fractions is presented. Both the frequency‐domain and time‐domain reduced‐order modeling procedures of the method are given. An example is included to demonstrate the method.

ISSN:0253-3839    

DOI:10.1080/02533839.1989.9677189

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

In this paper, we are concerned with the stability robustness of characteristic polynomials with perturbed coefficients for linear discrete‐time systems. An upper bound on the allowable coefficient perturbation of a Schur polynomial with retaining stability is obtained. The proposed upper bound is directly formulated in terms of the polynomial under consideration and its value can be determined by numerical computation. We also provide a sufficient condition for the stability of interval polynomials.

ISSN:0253-3839    

DOI:10.1080/02533839.1989.9677190

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

ISSN:0253-3839    

DOI:10.1080/02533839.1989.9677191

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

ISSN:0253-3839    

DOI:10.1080/02533839.1989.9677176

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor