Chongqing Normal University is a public university in Chongqing, China, founded in 1954.CNU has more than 1,800 staff members and 13,000 full-time domestic and international graduate and undergraduate students. In addition there are more than 20,000 adult education and self-teaching students. Wikipedia.
Huang G.,Chongqing Normal University
Current Organic Chemistry | Year: 2012
The pseudotrisaccharide allosamidin 1 is a potent family-18 chitinase inhibitor, and it demonstrates biological activities against insects, fungi, and the Plasmodium falciparum life cycle. Compound 1 contains two N-acetylhexosamine residues with the unusual D-allo-configuration and a novel aminocyclitol (i.e. allosamizoline 2), joined by two β-(1→4) glycosidic bonds. Many traditional syntheses of compounds 1-2 and their analogues have been reported. Herein, recent development for the synthesis of compounds 1-2 and their analogues was reviewed. Donohoe and Rosa's approach to allosamizoline 2 involves a key-step ring-closing metathesis (RCM) to form the cyclopentene core followed by halocyclization to form the oxazoline unit. Rojas et al. reported that rhodium-catalyzed oxidative cyclization of glucal 3-carbamates led to oxazolidinone-protected mannosamine derivatives. Huang et al. described the solid-phase synthesis of allosamidin 1 and its analogues. The compound 1 and its analogues were obtained by iterative glycosylation reactions, catalytic hydrogenation, acetylation, and deacetylation, respectively. Withers and his co-workers' research shows that chitobiose and chitotriose thiazolines exhibit chitinase inhibition activity. In a word, the goal is to investigate the novel methods for the synthesis of allosamidin and its analogues, which is convenient for the discovery of allosamidin analogues with high activity. © 2012 Bentham Science Publishers.
Li X.,Chongqing Normal University
International Journal for Numerical Methods in Engineering | Year: 2011
The Galerkin boundary node method (GBNM) is a boundary only meshless method that combines an equivalent variational formulation of boundary integral equations for governing equations and the moving least-squares (MLS) approximations for generating the trial and test functions. In this approach, boundary conditions can be implemented directly and easily despite of the fact that the MLS shape functions lack the delta function property. Besides, the resulting formulation inherits the symmetry and positive definiteness of the variational problems. The GBNM is developed in this paper for solving three-dimensional stationary incompressible Stokes flows in primitive variables. The numerical scheme is based on variational formulations for the first-kind integral equations, which are valid for both interior and exterior problems simultaneously. A rigorous error analysis and convergence study of the method for both the velocity and the pressure is presented in Sobolev spaces. The capability of the method is also illustrated and assessed through some selected numerical examples. © 2011 John Wiley & Sons, Ltd.
Zhang S.,Chongqing Normal University
Engineering Analysis with Boundary Elements | Year: 2015
This paper proposes a new iterative algorithm for the numerical solution of the Signorini problem for Laplacian using the boundary element method. Since the Signorini boundary conditions are equivalent to a projection fixed point problem, the Signorini boundary conditions can be transformed into a sequence of Dirichlet boundary conditions in a simple iterative manner. Therefore, the algorithm only requires solving a sequence of problems with straightforward boundary conditions. We also investigate the convergence criteria of the algorithm. As the iteration process is given on the Signorini boundary of the domain, the boundary element method is especially suitable for the algorithm. Finally, the numerical results demonstrate the accuracy and validity of the algorithm. © 2014 Elsevier Ltd. All rights reserved.
Li X.,Chongqing Normal University
Engineering Analysis with Boundary Elements | Year: 2014
A new implementation of the boundary node method (BNM) is developed in this paper for two- and three-dimensional potential problems. In our implementation, here called the dual boundary node method (DBNM), the conventional BIE is applied on the Dirichlet boundary and the hypersingular BIE is applied on the Neumann boundary. The DBNM can apply the boundary conditions directly and easily. And the number of both unknowns and system equations in the DBNM is only half of that in the BNM, thus the computing speed and efficiency are higher. The present method is applicable to other BIEs-based meshless methods, such as the boundary cloud method, the boundary element-free method and the boundary face method, in which the used shape functions lack the delta function property. Some numerical examples are given to demonstrate the method. © 2014 Elsevier Ltd.
Rui W.,Chongqing Normal University
Nonlinear Dynamics | Year: 2014
It is well known that it is difficult to obtain exact solutions of some partial differential equations with highly nonlinear terms or high order terms because these kinds of equations are not integrable in usual conditions. In this paper, by using the integral bifurcation method and factoring technique, we studied a generalized Gardner equation which contains both highly nonlinear terms and high order terms, some exact traveling wave solutions such as non-smooth peakon solutions, smooth periodic solutions and hyperbolic function solutions to the considered equation are obtained. Moreover, we demonstrate the profiles of these exact traveling wave solutions and discuss their dynamic properties through numerical simulations. © 2014 Springer Science+Business Media Dordrecht.