Singular potentials and double-force solutions for anisotropic laminates with coupled bending and stretching

Summary Exact solutions are obtained in the framework of the classical theory of laminates subjected to the action of normal moments, double forces, double moments or momentless double dipoles. Seven cases of such loads are considered and completed by considering the case of given transversal discontinuity of normal deflection. It is shown that, in contrast to the case of infinite straight dislocations in a pure in-plane problem, the energy of this eighth solution depends on the discontinuity orientation. Some numerical examples are presented. Besides the formal value, the obtained double-force and double-moment solutions, as well as dimensionless double dipoles, can be used to construct kernels of additional boundary integral equations (BIE). Due to the coupling phenomena in the BIE system for the region with a corner point, additional variable such as corner forces appear and require the mentioned equation. Received 22 June 1999; accepted for publication 6 March 2000     

Rigidity and regularity in group actions

Some new results on the rigidity of automorphism groups and the regularity of(?)-Neumann operator in group actions are presented.     

复合材料迭层板弯曲分步分析法

本文提出了一种用于分析复合材料迭层板弯曲的新方法。首先利用经典理论进行初步分析,之后,据所得横向剪力,设定横向剪切应变,再进一步分析。本文方法基本未知函数少,基本方程易解,计算精度较高。     

Anisotropy of a relict scalar field

It is shown that anisotropy of relict radiation can be caused by anisotropy of a relict scalar field, and large-scale structures of the relict scalar field can lead to large-scale structures of baryon matter. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 3–11, January, 2009.     

Flange earing and its control on deepdrawing of anisotropy circular sheets

The Hill's quadric anisotropy yield function and the Barlat-Lian anisotropy yield function describing well anisotropy sheet metal with stronger texture are introduced into a quadric-flow corner constitutive theory of elastic-plastic finite deformation suitable for deformation localization analysis. And then, the elastic-plastic large deformation finite element formulation based on the virtual power principle and the discrete Kirchhoff shell element model including the yield functions and the constitutive theory are established. The focus of the present research is on the numerical simulation of the flange earing of the deep-drawing of anisotropy circular sheets, based on the investigated results, the schemes for controlling the flange earing are proposed. Supported by NSFC(No. 19832020) and National Automobile Dynamic Simulation Laboratory of China.     

Ultrafast photo-induced turning of magnetization and its relaxation dynamics in GaMnAs

We report that,by linearly polarized pumping of different wavelengths,Kerr transients appear at zero magnetic field only in the case when GaMnAs samples are initialized at 3 K by first applying a 0.8 Tesla field and then returning to zero field.We find that,instead of magnetization precession,the near-band gap excitation induces a coherent out-of-plane turning of magnetization,which shows very long relaxation dynamics with no precession.When photon energy increases,the peak value of the Kerr transient incre...     

Near-Curie magnetic anomaly at the Ni/C interface observed by electron holography

We analyze with electron holography carried out in a transmission electron microscope the near-Curie behavior of magnetism at the edge of a Nickel thin film coated with Carbon. In-situ experiments with finely controlled variations of the sample temperature reveal an anomaly in the ferromagnetic to paramagnetic phase transition when the film temperature is a few degrees above the nominal Curie point. We interpret the anomaly as a strain-induced spin reorientation transition triggered by the differential thermal expansion of Carbon and Nickel. We present a model that quantitatively reproduces the main features of the observed signal. The model is developed in terms of an anisotropic, temperature dependent exchange coupling between the Nickel moments at the Carbon interface that favors their vertical alignment at low temperatures.     

Frequency responses of a linear laser with weakly coupled cavities containing a phase-anisotropic plate in the active part

On the basis of a general method for calculating linear weakly coupled anisotropic cavities, we obtain specific analytical expressions for the beat frequency between orthogonally polarized waves in a cavity that contains a phase-anisotropic plate in its active part. Experimental investigations are carried out. Good qualitative and quantitative agreement between theory and experiment is established. Belarusian State Polytechnic Academy, 65, F. Skorina Ave., Minsk, 220027, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 3, pp. 356–361, May–June, 1999.     

Power spectra and spatial pattern dynamics of a ring laser

Experimental measurements of power spectra of a single longitudinal and transverse mode ring dye laser are presented that reveal the critical slowing down of the laser near threshold. External pump noise serves as a probe of the frequency response of the dye laser. Detailed comparisons of the spectral characteristics with computer simulations and an approximate analytic theory are given. The dynamics of spatial pattern formation in a multimode dye laser is examined through measurements of first-passage-time distributions. A comparison of the experiments with computer simulations based on a simple theoretical model of the two-mode laser shows qualitative agreement. These measurements indicate that there are a variety of complex phenomena associated with the transverse mode pattern formation dynamics that need to be addressed theoretically and studied further experimentally.     

Dynamics of Ice Surfaces

The dynamics of faceted and partially faceted single crystal and polycrystalline ice are reviewed with an emphasis on the manner in which microscopic effects produce macroscopic shapes. Our understanding of the former is rooted in the basic kinetics common to all materials and our pursuit of the latter is largely motivated by the striking patterns exhibited in the natural environment when water changes phase to become ice.