نتایج جستجو برای: symmetry

تعداد نتایج: 85546  

In this paper, we will obtain first integral, integrating factor and λ-symmetry of third-order ODEs u ⃛=F(x,u,u ̇,u ̈). Also we compare Prelle -Singer (PS) method and λ-symmetry method for third-order differential equations.In this paper, we will obtain first integral, integrating factor and λ-symmetry of third-order ODEs u ⃛=F(x,u,u ̇,u ̈). Also we compare Prelle -Singer (PS) method and λ-symmetry m...

As it is well known, symmetry plays a crucial role in the theoretical physics. On other hand, the Noether symmetry is a useful procedure to select models motivated at a fundamental level, and to discover the exact solution to the given lagrangian. In this work, Noether symmetry in f(T) theory on a spatially homogeneous and anisotropic Bianchi type I universe is considered. We discuss the Lagran...

The paper is devoted to an application of Lie group theory to differential equations. The basic infinitesimal method for calculating symmetry group is presented, and used to determine general symmetry group of some differential equations. We include a number of important applications including integration of ordinary differential equations and finding some solutions of partial differential equa...

Symmetry or asymmetry of the business cycle is an important issue in order to select the behavior patterns and prediction of macroeconomic fluctuations. Factors such as oil prices, the financial crisis, uncertainty, the delay on learning, etc., Can cause lack of symmetry in the cycle. Decomposition of the business cycle by wavelet transform, which is strong instrument for processing data, and r...

To understand the mechanism of superconductivity in unconventional super onductors is one of the big challenges in the field of superconductivity. Based on the BCS theory, there is a direct relation between the pairing mechanism and the symmetry of the order parameter. Therefore, identification of the structure of the superconducting gap or the order parameter provides key information on the pa...

‎In this work‎, ‎a regular polygon with $n$ sides is described by a periodic (circular) sequence with period $n$‎. ‎Each element of the sequence represents a vertex of the polygon‎. ‎Each symmetry of the polygon is the rotation of the polygon around the center-point and/or flipping around a symmetry axis‎. ‎Here each symmetry is considered as a system that takes an input circular sequence and g...

Elham Behshad, Mohsen Mohammadzadeh,

In recent years, some investigations have been carried out to examine the assumptions like stationarity, symmetry and separability of spatio-temporal covariance function which would considerably simplify fitting a valid covariance model to the data by parametric and nonparametric methods. In this article, assuming a Gaussian random field, we consider the likelihood ratio separability test, a va...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور - دانشکده علوم پایه 1387

چکیده ندارد.

Fullerene chemistry is nowadays a well-established field of both theoretical and experimental investigations‎. This study considers the symmetry of small fullerenes cage C24 and C28‎. ‎Using PM3 program for C24 and C28 fullerenes, Oh and Td symmetry were confirmed, respectively‎. ‎ The mentioned algorithm to compute the automorphism group of these fullerenes with connectivity and geometry of th...

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