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991.
Hossein Motavalli Amin Rezaei Akbarieh 《International Journal of Theoretical Physics》2010,49(9):2074-2079
We present a general construction for ladder operators for the special orthogonal functions based on Nikiforov-Uvarov mathematical
formalism. A list of creation and annihilation operators are provided for the well known special functions. Furthermore, we
establish the dynamic group associated with these operators. 相似文献
992.
Hossein Farajollahi Mehrdad Farhoudi Hossein Shojaie 《International Journal of Theoretical Physics》2010,49(10):2558-2568
We study longstanding problem of cosmological clock in the context of Brans–Dicke theory of gravitation. We present the Hamiltonian
formulation of the theory for a class of spatially homogeneous cosmological models. Then, we show that formulation of the
Brans–Dicke theory in the Einstein frame allows how an identification of an appropriate cosmological time variable, as a function
of the scalar field in the theory, can be emerged in quantum cosmology. The classical and quantum results are applied to the
Friedmann–Robertson–Walker cosmological models. 相似文献
993.
994.
Hossein Movasati 《The Ramanujan Journal》2008,17(1):53-76
In the present article we define the algebra of differential modular forms and we prove that it is generated by Eisenstein
series of weight 2, 4 and 6. We define Hecke operators on them, find some analytic relations between these Eisenstein series
and obtain them in a natural way as coefficients of a family of elliptic curves. The fact that a complex manifold over the
moduli of polarized Hodge structures in the case h
10=h
01=1 has an algebraic structure with an action of an algebraic group plays a basic role in all of the proofs.
相似文献
995.
Hossein Abbaspour 《Comptes Rendus Mathematique》2004,338(9):713-718
Let M be a connected, closed, oriented and smooth manifold of dimension d. Let LM be the space of loops in M. Chas and Sullivan introduced the loop product, an associative product of degree ?d on the homology of LM. In this Note we aim at identifying 3-manifolds with “non-trivial” loop products. To cite this article: H. Abbaspour, C. R. Acad. Sci. Paris, Ser. I 338 (2004). 相似文献
996.
Houshang Behravesh Mohammad Hossein Jafari 《数学物理学报(B辑英文版)》2007,27(2):297-300
The quantities c(G), q(G) and p(G) for finite groups were defined by H. Behravesh. In this article, these quantities for the alternating group An and the symmetric group Sn are calculated. It is shown that c(G) = q(G)=p(G) = n, when G = An or Sn. 相似文献
997.
Hossein Tavana Dietmar Appelhans Rong-Chuan Zhuang Stefan Zschoche Karina Grundke Michael L. Hair A. Wilhelm Neumann 《Colloid and polymer science》2006,284(5):497-505
Surface energetics of two fluorinated maleimide copolymers containing fluorinated side chain, i.e., poly(ethene-alt-N-(4-(perfluoroheptylcarbonyl)aminobutyl)maleimide) (ETMF) and poly(octadecene-alt-N-(4-(perfluoroheptylcarbonyl)aminobutyl)maleimide) (ODMF), are studied by contact angle measurements with 10 liquids consisting
of fairly bulky molecules. Because of the inertness of octamethylcyclotetrasiloxane (OMCTS) and decamethylcyclopentasiloxane
(DMCPS) molecules, their contact angles are used to determine the surface tension of the two polymers. It is found that other
liquids show specific interactions with the ETMF films, and their contact angles deviate from a smooth curve that represents
the surface tension of ETMF, i.e., 11.00 mJ/m2. On ODMF surfaces, only OMCTS and DMCPS yield useful contact angles. Other liquids either dissolve the polymer film or show
a slip-stick pattern. This finding is discussed in terms of interactions between segments of the polymer chains and the test
liquids. OMCTS and DMCPS are suggested as the appropriate probe liquids, meeting specific criteria necessary for the determination
of accurate surface tension of fluoropolymers. 相似文献
998.
The optimized geometries, molecular properties, and stabilities of new noble gas molecules, XXeOH (X = F, Cl, Br, and I), were studied using CCSD, MP2, CAM-B3LYP, and WB97XD methods and large basis sets. All XXeOH molecules showed equilibrium structures with Cs symmetry. The results also showed that some bonds in XXeOH could be presented as a typical ionic bond. An alteration in ion-pair character was observed for IXeOH, showing two OH ? and IXe + parts, while in other molecules, they could be presented as XeOH + and X ? . Two decomposition routes were proposed for these molecules that showed high exothermic reactions. However, despite their low thermodynamic stabilities, their decomposition rate constants were small and all molecules (except BrXeOH) had high kinetic stabilities, indicating the possibility for identification and characterization of these molecules. However, in addition to the calculation of their vibrational frequencies, NBO atomic charges, and hybridizations, the bonding properties of XXeOH molecules were studied by AIM calculations (to calculate electron densities, bond elipticities, and Laplacian of electron densities) and second-order intramolecular perturbation energies using NBO calculations. Moreover, the ease of formations and relative stabilities of XXeOH molecules were compared using heats of formations, Gibbs free energies of formations and isodesmic reactions. These calculations showed that the stability of XXeOH molecules was decreased from F to I. 相似文献
999.
Ab initio calculations were used to analyze the interactions between thiohypohalous acids (HSX; X = F, Cl, Br, I) and methylphosphine derivatives (PH n Me3?n , n = 0–3) at the MP2/aug-cc-pVDZ level of theory. Interaction of HSX with PH n Me3?n leads to both hydrogen bond (HSX–PH n Me3?n –HB) as well as halogen bond (HSX–PH n Me3?n –XB) complexes. Stabilities of both HB and XB complexes increase with basicity of the phosphines. However, HB complexes of a phosphine molecule with different HSX have the same order of stabilities, but XB complexes of heavier thiohypohalous acids are more stable. Electron densities of complexes were characterized with the atoms in molecules methodology. The charge transfer within dimers was analyzed by means of natural bond orbitals. 相似文献
1000.
1,3-Butadiyne, 1,3,5-hexatriyne, 1,3,5,7-octatetrayne, and 1,3,5,7,9-decapentayne are small oligomeric forms of acetylene. These oligomers participate in cyclization reactions to form ladder-like structures. Enthalpies, ?H, and Gibbs free energies, ?G, of the cyclization reactions were calculated employing MP2 and B3LYP methods. The calculated ?H and ?G were positive, and their variation versus carbon atoms number, n, was fitted in linear functions as ?H(n) = a+bn. The calculations were performed on the structures with carbon numbers up to 20. Also, consecutive cyclization reactions between acetylene molecules were studied. During these consecutive reactions, two different structures, zigzag-ladder-like and cyclic molecules with tetragonal rings, were produced. Among the cyclic structures, the hexagonal form was the most stable structure. The calculated ?H and ?G of formation of zigzag-ladder-like molecules were excellently fitted in linear functions. The obtained functions for ?H and ?G calculated by MP2 method are ?H(n) = 139.67?126.44n and ?G(n) = 80.987?75.684n, respectively. 相似文献