Elastic instability of a uniformly compressed annular plate with axisymmetric initial deflection

This paper presents a theoretical study of the elastic instability of a uniformly compressed, thin, circular annular plate with axisymmetric initial deflection. The dynamic version of the nonlinear Marguerre plate theory is used, and the linear free vibration problems around the axisymmetric finite deformation of the plate are solved by a finite difference method. By examining the frequency spectrum with various asymmetric modes, the critical compressive load under which the axisymmetric additional deformation of the plate becomes unstable due to the bifurcation buckling is determined, which is found to depend severely on the magnitude of the axisymmetric initial deflection.     

A Boundary Value Problem for an Infinite Elastic Strip with a Semi-infinite Crack

In this paper we study a boundary value problem for an infinite elastic strip with a semi-infinite crack. By using the single and double layer potentials this problem is reduced to a singular integral equation, which is uniquely solved in the Hölder spaces by the Fredholm alternative.     

ESR study of the molecular orientation and dynamics of stable organic radicals included in the 1‐D organic nanochannels of 2,4,6‐tris‐4‐(chlorophenoxy)‐1,3,5‐triazine

The molecular orientation and dynamics of the organic stable radicals such as 2,2,6,6‐tetramethyl‐1‐piperidinyl‐1‐oxyl (TEMPO) or 4‐hydroxy‐TEMPO (TEMPOL) included in the one‐dimensional (1‐D) organic nanochannels of 2,4,6‐tris‐4‐(chlorophenoxy)‐1,3,5‐triazine (CLPOT) were investigated by examining the inclusion compounds (ICs) diluted by the co‐inclusion of non‐radicals using ESR spectroscopy. Spectral simulation showed that the axial rotation of TEMPO or TEMPOL molecules is excited in the nanochannels with activation energies of 8 and 7 kJ mol^?1, respectively. The rotation axis was estimated to be tilted towards the principal x direction in the axis system of the g ‐tensor of the respective radicals. This is quite different from that for similar ICs in the nanochannels of tris(o‐phenylenedioxy)cyclotriphosphazene (TPP), in which the radicals are axially rotating around the principal axis y of the g‐tensor. The difference is attributed to the larger nanospace of the CLPOT nanochannels. Copyright © 2012 John Wiley & Sons, Ltd.     

Postgel properties in the statistical crosslinking of heterochains. I. Systems with N types of chains

The heterochain crosslinking model describes nonrandom crosslinking of polymer chains and is an extension of the classical Flory/Stockmayer gelation theory. We consider the postgelation relationship for the system consisting of N types of polymer chains, in which the probability that a crosslink point on an i‐type chain is connected to a j‐type chain is explicitly given by p_ij. The analytical solutions for the weight fraction of the sol, the number‐average and weight‐average molecular weights within the sol fraction, and the crosslinking density within the sol and gel fractions are derived for the systems, with each type of chain conforming to the Schulz–Zimm distribution. Illustrative calculations are shown for the systems consisting of two and three types of chains, and the obtained results agree with those from the Monte Carlo method. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 2333–2341, 2000     

Temperature dependence of terahertz radiation from n-type InSb and n-type InAs surfaces

The azimuthal angle dependence and the temperature dependence of terahertz (THz) radiation generated from n-type (111) InSb and n-type (111) InAs surfaces irradiated with ∼80 fs near-infrared laser pulses are investigated. The azimuthal angle dependence shows that the contribution of the difference-frequency mixing (DFM) is not dominant for both materials at the excitation density of ∼1 GW/cm². At an appropriate azimuthal angle, the radiation due to DFM is excluded from the total THz radiation and the temperature dependence of THz radiation due to the surge current is observed. The increase of THz radiation with decrease of the temperature is found to be much more pronounced for InSb than for InAs. The different temperature dependence can be attributed to the different radiation mechanisms dominant for both materials. Especially, the temperature dependence of the THz radiation from InSb is well explained by the photo-Dember effect. Received: 9 May 2000 / Revised version: 17 August 2000 / Published online: 5 October 2000