45 research outputs found
Numerical Steady-State Solutions of Non-Linear DAE's Arising in RF Communication Circuit Design
No full textDunlavy, Danny; Joo, Sookhyung; Lin, Runchang; Marcia, Roummel; Minut, Aurelia; Sun, Jianzhong. (2001). Numerical Steady-State Solutions of Non-Linear DAE's Arising in RF Communication Circuit Design. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/3549
Discontinuous Galerkin least-squares finite element methods for singularly perturbed reaction-diffusion problems with discontinuous coefficients and boundary singularities
No full textIn this paper, a discontinuous Galerkin least-squares finite element method is developed for singularly perturbed reaction-diffusion problems with discontinuous coefficients and boundary singularities by recasting the second-order elliptic equations as a system of first-order equations. In a companion paper (Lin in SIAM J Numer Anal 47:89-108, 2008) a similar method has been developed for problems with continuous data and shown to be well-posed, uniformly convergent, and optimal in convergence rate. In this paper the method is modified to take care of conditions that arise at interfaces and boundary singularities. Coercivity and uniform error estimates for the finite element approximation are established in an appropriately scaled norm. Numerical examples confirm the theoretical results. © 2008 Springer-Verlag
A discontinuous Galerkin least-squares finite element method for solving coupled singularly perturbed reaction–diffusion equations
No full textA discontinuous Galerkin least-squares finite element method is proposed to solve coupled reaction–diffusion equations with singular perturbations. This method produces solutions without numerical oscillations when uniform meshes are used. Numerical examples are provided to demonstrate the efficiency of the method
Yangyin Runchang Decoction Improves Intestinal Motility in Mice with Atropine/Diphenoxylate-Induced Slow-Transit Constipation
No full textThis study assessed the efficacy and mechanism of action of Yangyin Runchang decoction (YRD) in the treatment of slow-transit constipation (STC). ICR mice were randomly divided into four groups (n=10/group) and treated with saline (normal control; NC), atropine/diphenoxylate (model control; MC; 20 mg/kg), or atropine/diphenoxylate plus low-dose YRD (L-YRD; 29.6 g/kg) or high-dose YRD (H-YRD; 59.2 g/kg). Intestinal motility was assessed by evaluating feces and the intestinal transit rate (ITR). The serum level of stem cell factor (SCF) and changes in interstitial cells of Cajal (ICCs) were also evaluated. Additionally, the expression of SCF and c-kit and the intracellular Ca2+ concentration [Ca2+]I were investigated. Fecal volume and ITR were greater in the L-YRD and H-YRD groups than in the MC group. The serum SCF level was lower in the MC group than in the NC group; this effect was ameliorated in the YRD-treated mice. Additionally, YRD-treated mice had more ICCs and elevated expression of c-kit and membrane-bound SCF, and YRD also increased [Ca2+]I in vitro in isolated ICCs. YRD treatment in this STC mouse model was effective, possibly via the restoration of the SCF/c-kit pathway, increase in the ICC count, and enhancement of ICC function by increasing [Ca2+]i.</jats:p
Discontinuous discretization for least-squares formulation of singularly perturbed reaction-diffusion problems in one and two dimensions
No full textIn this paper, we consider the singularly perturbed reaction-diffusion problem in one and two dimensions. The boundary value problem is decomposed into a first-order system to which a suitable weighted least-squares formulation is proposed. A robust, stable, and efficient approach is developed baaed on local discontinuous Galerkin (LDG) discretization for the weak form. Uniform error estimates are derived. Numerical examples are presented to illustrate the method and the theoretical results. Comparison studies are made between the proposed method and other methods. © 2008 Society for Industrial and Applied Mathematics
A DG Least-Squares Finite Element Method for Nagumo’s Nerve Equation with Fast Reaction: A Numerical Study
No full textChina-EU Energy Cooperation Roadmap 2020 _ Concept Note
No full textThe process for the definition of an Energy Cooperation Roadmap between the EU and China was officially initiated at the first meeting of the Energy Security Working Group held in Beijing in February 2013, following the China-EU Joint Declaration on Energy Security of May 2012 that stated the formal establishment of the relationships between China and the EU as energy consumers and strategic partners. This Concept Note on China-EU Energy Cooperation Roadmap 2020 has been elaborated by the Europe-China Clean Energy Centre (EC2) and it provides suggestions on cooperation goals and recommendations for a Roadmap to 202
L\u3csup\u3e∞\u3c/sup\u3e estimation of the LDG method for 1-d singularly perturbed convection-diffusion problems
No full textPointwise error estimates of the local discontinuous Galerkin (LDG) method for a one-dimensional singularly perturbed problem are studied. Several uniform L∞ error bounds for the LDG approximation to the solution and its derivative are established on a Shishkin-type mesh. Numerical experiments are presented
Contemporary Mathematics Derivative Superconvergence of Equilateral Triangular Finite Elements
No full textAbstract. Derivative superconvergent points under locally equilateral triangular mesh for both the Poisson and Laplace equations are reported. Our results are conclusive. For the Poisson equation, symmetry points are only superconvergent points for cubic and higher order elements. However, for the Laplace equation, most of superconvergent points are not symmetry points, which are reported for the first time in the literature. 1
