Abstract Based on Brownian dynamics simulations we study the collective behavior of a two-dimensional system repulsively interacting colloidal particles, where each particle is propelled by repulsive feedback force with time delay τ . Although pair interactions are purely isotropic observe spontaneous, large-scale alignment velocity vectors. This phenomenon persists for long times and occurs in...

Abstract: This paper is concerned with a two species Leslie-Gower predator-prey system with time delay. By regarding the delay τ as the bifurcation parameter, the stability of positive equilibrium and Hopf bifurcations are investigated. Furthermore, the direction of Hopf bifurcations and the stability of bifurcating periodic solutions are determined by applying the norm form theory and the cent...

Stability of linear delayed systems subjected to digital control is analyzed. These systems can typically be written in the form ẋ(t) = Ax(t) + Bx(t− τ) + Cx(tj−1) , t ∈ [tj , tj+1) , where tj = j∆t with ∆t being the sampling period for the digital controller. The point-delay term x(t−τ) is assumed to be inherently present in the governing equation of the uncontrolled system, while the term x(t...

In this paper, we will establish some new oscillation criteria for the second-order superlinear neutral delay dynamic equation of Emden-Fowler type [ a(t)(y(t) + r(t)y(τ(t))) ]∆ + p(t) |y(δ(t))| signy(δ(t)) = 0, on a time scale T; here γ > 1, a(t), r(t), τ(t), p(t) and δ(t)real-valued positive functions defined on T. Our results in the special case when T = R, improve the oscillation results fo...

We apply hp-cloud method to the radial Dirac eigenvalue problem. The difficulty of occurrence of spurious values among the genuine eigenvalues is treated. The method of treatment is based on assuming hp-cloud Petrov-Galerkin scheme to construct the weak formulation of the problem which adds a consistent diffusivity to the variational formulation without deforming the equation. The size of the a...

Binary and ternary 5-bit programmable dispersion matrix is built to control a two-channel receives beamformer at 1550 nm. Phase measurements for the delay configurations along with beam-patterns at RF frequencies 0.2-1 GHz are presented. 1INTRODUCTION Many RF and microwave systems, such as high-resolution phased-array antennas and signal processing electronics, require true-time delay (TTD) pha...

This lab had two objectives. First, we wished to image a variety of fluorescing single photon sources using a confocal microscopy setup. Second, we wished to detect photon antibunching using a Hanbury Brown & Twiss setup in at least one of the samples. We were able to successfully image samples of Single Walled Carbon Nanotubes, Nanodiamonds, Gold Nanoparticles, and Colloidal CdSe Quantum Dots,...

The Thouless formula G = (e 2 /h)(E c /∆) for the two-probe dc con-ductance G of a d-dimensional mesoscopic cube is re-analysed to relate its quantum capacitance C Q to the reciprocal of the level spacing ∆. To this end, the escape timescale τ occurring in the Thouless correlation energy E c = ¯ h/τ is interpreted as the time constant τ = RC Q with RG ≡ 1, giving at once C Q = (e 2 /2π∆). Thus,...