排序方式: 共有150条查询结果,搜索用时 15 毫秒
141.
In this paper, we obtain exact soliton solutions of the modified KdV equation, inhomogeneous nonlinear Schrödinger equation and G(m, n) equation with variable-coefficients using solitary wave ansatz. The constraint conditions among the time-dependent coefficients turn out as necessary conditions for the solitons to exist. Numerical simulations for dark and bright soliton solutions for the mKdV equation are also given. 相似文献
142.
In this paper, we study the head-on collision between two dust-ion-acoustic (DIA) solitons in quantum electron-dust-ion plasma. Using the extended Poincaré–Lighthill–Kuo (PLK) method, we obtain the Korteweg–de Vries (KdV) equations, the phase shifts and the trajectories after the head-on collision of the two DIA solitons. We investigate the effect of quantum diffraction parameters for electrons and ions (H e, H i), the Fermi temperature ratio (σ) and the dust charged number density (n d0) on the phase shifts. Different values of μ?=?z d0(n d0/n i0) and μ d?=?z d0(m i/m d) are taken to discuss the effects on phase shifts, where z d0 denotes the dust charge number, n j0 represents the equilibrium number density and m j is the mass of the jth species (j?=?e, i, d for electrons, ions and dust particles, respectively). It is observed that the phase shifts are significantly affected by the plasma parameters. 相似文献
143.
SUMIT KUMAR UPADHYAY SHIV DATT KUMAR RAJA SRIDHARAN 《Proceedings Mathematical Sciences》2013,123(4):469-478
In this article we give a bound on the number of generators of a finitely generated projective module of constant rank over a commutative Noetherian ring in terms of the rank of the module and the dimension of the ring. Under certain conditions we provide an improvement to the Forster–Swan bound in case of finitely generated projective modules of rank n over an affine algebra over a finite field or an algebraically closed field. 相似文献
144.
This paper deals with the study of behaviour of G-associated ideals and strong Krull G-associated ideals with flat base change of rings and behaviour of G-associated ideals with short exact sequences over rings graded by finitely generated abelian group G. 相似文献
145.
In this paper, we report a new method to determine the effective atomic number, Z
eff, of composite materials for Compton effect in the γ-ray region 280–1115 keV based on the theoretically obtained Klein–Nishina scattering cross-sections in the angular range
50°–100° as well as a method to experimentally measure differential incoherent (Compton) scattering cross-sections in this
angular range. The method was employed to evaluate Z
eff for different inorganic compounds containing elements in the range Z = 1–56, at three scattering angles 60°, 80° and 100° at three incident gamma energies 279.1 keV, 661.6 keV and 1115.5 keV
and we have verified this method to be an appropriate method. Interestingly, the Z
eff values so obtained for the inorganic compounds were found to be equal to the total number of electrons present in the sample
as given by the atomic number of the elements constituting the sample in accordance with the chemical formula of the sample.
This was the case at all the three energies. 相似文献
146.
The projected shell model (PSM) calculations have been performed for the neutron-rich even–even 102?110Mo and odd—even 103?109Mo isotopes. The present calculation reproduces the available experimental data on the yrast bands. In case of even–even nuclei, the structure of yrast bands is analysed and electromagnetic quantities are compared with the available experimental data. The g-factors have been predicted for high spin states. For the odd-neutron nuclei, the structures of yrast positive- and negative-parity bands are analysed and found to be in reasonable agreement with the experiments for 103?107Mo. The disagreement of the calculated and observed plots for energy staggering quantity clearly establishes the occurrence of sizable triaxiality in 103,105Mo and also predicts a decrease in the quantum of triaxiality with increasing neutron number and angular momentum for odd mass neutron-rich Mo isotopes. 相似文献
147.
ANIRUDDHA KUMAR R B BHATT P G BEHERE MOHD AFZAL ARUN KUMAR J P NILAYA D J BISWAS 《Pramana》2014,82(2):237-242
Removal of a thin oxide layer from a tungsten ribbon and ThO2 particulates from zircaloy surface was achieved using a pulsed Nd:YAG laser. The removal mechanism of the oxide layer from the tungsten ribbon was identified as spallation or sublimation depending on the wavelength and fluence of the coherent radiation. The oxidized and cleaned surfaces were analysed by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDS) and atomic force microscopy (AFM). Laser-cleaned tungsten ribbons were used in a thermal ionization mass spectrometer (TIMS) to determine isotopic composition of neodymium atoms. The fundamental (1064 nm) and the third harmonic (355 nm) radiations were found to be the most effective in removing ThO2 particulates from the zircaloy surface. Decontamination efficiency was found to be critically dependent on the wavelength of the coherent radiation and number of exposures. The mechanism of cleaning of ThO2 particulates from the zircaloy surface at different wavelengths of the incident radiation has been explained qualitatively. 相似文献
148.
SHRAWAN KUMAR 《Transformation Groups》2014,19(4):1051-1148
The classical Hermitian eigenvalue problem addresses the following question: What are the possible eigenvalues of the sum A + B of two Hermitian matrices A and B, provided we fix the eigenvalues of A and B. A systematic study of this problem was initiated by H. Weyl (1912). By virtue of contributions from a long list of mathematicians, notably Weyl (1912), Horn (1962), Klyachko (1998) and Knutson–Tao (1999), the problem is finally settled. The solution asserts that the eigenvalues of A + B are given in terms of certain system of linear inequalities in the eigenvalues of A and B. These inequalities (called the Hom inequalities) are given explicitly in terms of certain triples of Schubert classes in the singular cohomology of Grassmannians and the standard cup product. Belkale (2001) gave a smaller set of inequalities for the problem in this case (which was shown to be optimal by Knutson–Tao–Woodward). The Hermitian eigenvalue problem has been extended by Berenstein–Sjamaar (2000) and Kapovich–Leeb–Millson (2009) for any semisimple complex algebraic group G. Their solution is again in terms of a system of linear inequalities obtained from certain triples of Schubert classes in the singular cohomology of the partial ag varieties G/P (P being a maximal parabolic subgroup) and the standard cup product. However, their solution is far from being optimal. In a joint work with P. Belkale, we define a deformation of the cup product in the cohomology of G/P and use this new product to generate our system of inequalities which solves the problem for any G optimally (as shown by Ressayre). This article is a survey (with more or less complete proofs) of this additive eigenvalue problem. The eigenvalue problem is equivalent to the saturated tensor product problem. We also give an extension of the saturated tensor product problem to the saturated restriction problem for any pair G ? ? of connected reductive algebraic groups. In the appendix by M. Kapovich, a connection between metric geometry and the representation theory of complex semisimple algebraic groups is explained. The connection runs through the theory of buildings. This connection is exploited to give a uniform (though not optimal) saturation factor for any G. 相似文献
149.
SUBALA MONDAL SUMON RAY ANIMESH CHATTOPADHYAY DEBABRATA NANDI ROSHNI SARKAR ALAK KUMAR GHOSH 《国际化学动力学杂志》2014,46(10):587-596
The kinetics of the interactions between three sulfur‐containing ligands, thioglycolic acid, 2‐thiouracil, glutathione, and the title complex, have been studied spectrophotometrically in aqueous medium as a function of the concentrations of the ligands, temperature, and pH at constant ionic strength. The reactions follow a two‐step process in which the first step is ligand‐dependent and the second step is ligand‐independent chelation. Rate constants (k1 ~10?3 s?1 and k2 ~10?5 s?1) and activation parameters (for thioglycolic acid: ΔH1≠ = 22.4 ± 3.0 kJ mol?1, ΔS1≠ = ?220 ± 11 J K?1 mol?1, ΔH2≠ = 38.5 ± 1.3 kJ mol?1, ΔS2≠ = ?204 ± 4 J K?1 mol?1; for 2‐thiouracil: ΔH1≠ = 42.2 ± 2.0 kJ mol?1, ΔS1≠ = ?169 ± 6 J K?1 mol?1, ΔH2≠ = 66.1 ± 0.5 kJ mol?1, ΔS2≠ = ?124 ± 2 J K?1 mol?1; for glutathione: ΔH1≠ = 47.2 ± 1.7 kJ mol?1, ΔS1≠ = ?155 ± 5 J K?1mol?1, ΔH2≠ = 73.5 ± 1.1 kJ mol?1, ΔS2≠ = ?105 ± 3 J K?1 mol?1) were calculated. Based on the kinetic and activation parameters, an associative interchange mechanism is proposed for the interaction processes. The products of the reactions have been characterized from IR and ESI mass spectroscopic analysis. A rate law involving the outer sphere association complex formation has been established as 相似文献
150.
KASTHURIAH Maddali UMA RAVI SANKAR Arigala SIVA KUMAR Bitragunta SURESH REDDY Cirandur NAGA RAJU Chamarthi 《中国化学》2009,27(2):408-412
A few new seven-membered phosphorus heterocyclic compounds and bis-phosphonates (5a—5g, 5f’, 5g’, 9 and 10) were prepared by the reaction of 4-bromo dioxaphosphepin (2) with various Grignard reagents followed by their oxidation with H2O2. All the compounds were thoroughly characterized by elemental analysis, IR, 1H, 13C, 31P NMR and mass spectral data. Their antimicrobial activity was evaluated and some of them possess significant activity. 相似文献