Asymmetry Of Boundary Conditions Research Articles

Local influence of boundary conditions on a confined supercooled colloidal liquid

We study confined colloidal suspensions as a model system which approximates the behavior of confined small molecule glass-formers. Dense colloidal suspensions become glassier when confined between parallel glass plates. We use confocal microscopy to study the motion of confined colloidal particles. In particular, we examine the influence particles stuck to the glass plates have on nearby free particles. Confinement appears to be the primary influence slowing free particle motion, and proximity to stuck particles causes a secondary reduction in the mobility of free particles. Overall, particle mobility is fairly constant across the width of the sample chamber, but a strong asymmetry in boundary conditions results in a slight gradient of particle mobility.

Inherent Continuous, Hysteretic Free and Memorized Gray Scale of FLC Display Cells Based on Bi- and Multistability Effects

Ferroelectric liquid crystal (FLC) mixtures with high spontaneous polarization (Ps > 50 nC/cm 2 ) possessing ferroelectric domains [1] exhibit a multistability effect which has been known for more than 10 years [2, 3]. Any light transmission level can be memorized in the effect after the driving voltage is switched off. The multistability effect is responsible for three new electrooptical modes with continuous, memorized and reversible gray scale. Depending on the asymmetry in boundary conditions and crystallooptical parameters of the cell, these modes differ among themselves under the shape of the gray scale curve that can be either S (double or single) or V-shaped. Origin of the phenomenon is under consideration here.

Stability analysis of dynamic ratcheting in elastoplastic systems

This paper deals with the stability and the dynamics of a harmonically excited elastic perfectly plastic asymmetrical oscillator. The hysteretical system is written as a nonsmooth, forced autonomous system. The dimension of the phase space can be reduced using adapted variables. It is shown that asymmetry of boundary conditions (forcing term) and material asymmetry lead to an equivalent system for this simple structural case. The forced vibration of such an oscillator is treated by a numerical approach by using time locating techniques. Stability of the limit cycles is analytically investigated with a perturbation approach. The boundary between elastoplastic shakedown and dynamic ratcheting is given in closed form. It is shown that the divergence rate is strongly correlated to the internal asymmetry of the oscillator.

Kinetic simulation on ion acoustic wave in gas discharge plasma with convective scheme

In a one-dimensional plasma-sheath system representing a concave quasistationary electric potential typical of a negatively charged system, oscillations of ion are simulated by the aid of a convective scheme useful for weakly ionized plasma, and are theoretically investigated. The frequency spectra of the ion current through a cathode reveal to us that two modes of ion acoustic waves are dominant; a high and a low frequency mode. By deriving a linear differential equation with a dissipation and an ion flow, and taking for granted the sheath width and the distribution of ion flow velocity, the dispersion relation for a finite length system can be calculated. The simulation results, such as the reinforcement of the low frequency mode and the suppression of the high frequency mode, are satisfactorily corroborated by the linear theory. The instabilities of the waves are caused by the asymmetry of boundary conditions and by the dissipative effect.

The effect of asymmetry of boundary conditions on the properties of acoustic superlattices

The effect of asymmetry of boundary conditions on the acoustic properties of an acoustic superlattice transducer is studied theoretically. The resonance frequency is influenced by the thickness unequality of the positive and negative domains. This may be used to tailor the property of the ASL transducer.

Modal analysis of continuous rotor-bearing systems

Modal analysis is applied to continuous rotor systems with various boundary conditions which include isotropic and anisotropic natural boundary conditions. The rotor includes the effects of rotary inertia and gyroscopic moment. In particular, the whirl speeds and mode shapes, backward and forward, of a rotating shaft are obtained as spin speed and boundary conditions vary, and the unbalance responses are calculated by using modal analysis. The effects of asymmetry in boundary conditions on the system dynamic characteristics are also investigated.