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211.
We summarize the recent effective field theory (EFT) studies of low-energy electroweak reactions of astrophysical interest, relevant to big-bang nucleosynthesis. The zero energy astrophysical S(0) factor for the thermal proton radiative capture by deuteron is calculated with pionless EFT. The astrophysical S(0) factor is accurately determined to be S(0)=0.243 eV·b up to the leading order (LO). At zero energies, magnetic transition M1 gives the dominant contribution. The M1 amplitude is calculated up to the LO. A good, quantitative agreement between theoretical and experimental results is found for all observables. The demonstrations of cutoff independent calculation have also been presented. 相似文献
212.
The effects of sample size on the galvanomagnetice properties of semimetal nanowires are theoretically investigated. Transverse magnetoresistance (TMR) ratios have been calculated within a Boltzmann Transport Equation (BTE) approach by specular reflection approximation. Temperature and radius dependence of the transverse magnetoresistance of cylindrical Bismuth nanowires are given. The obtained values are in good agreement with the experimental results, reported by Heremans et al. 相似文献
213.
The classical Mazur–Ulam theorem which states that every surjective isometry between real normed spaces is affine is not valid for non-Archimedean normed spaces. In this paper, we establish a Mazur–Ulam theorem in the non-Archimedean strictly convex normed spaces. 相似文献
214.
Mohammad Ali Zolfigol Maryam Kiany-Borazjani Majid M. Sadeghi Iraj Mohammadpoor-Baltork Hamid Reza Memarian 《合成通讯》2013,43(3):551-558
A combination of oxalic acid dihydrate and sodium nitrite in the presence of wet SiO2 was used as an effective oxidizing agent for the oxidation of dihydropyridines to their corresponding pyridine derivatives at room temperature with excellent yields. 相似文献
215.
Initial stress in rings is one of the destructive effects which is almost inevitable due to various reasons such as being subsystems of a shrink-fitted joint, imperfections in the manufacturing, assembly or misalignment of the supporting mounts, and unbalancing in rotating condition. So, in this paper we focus on the effect of the initial stress and its variation with time on the dynamics of the pre-stressed ring. For this purpose, the equation of motion for in-plane bending vibration of a thin ring is derived using Hamilton’s principle. It is assumed that the initial stress is due to the distributed radially time-varying pressure. By representing the dynamic initial stress in the coefficients of the equation of motion; the equation is converted to Mathieu’s equation. The strained parameters method has been used to obtain the stability regions of motion and transition curves. Furthermore, to validate the obtained stability regions, numerical solutions of the equation of motion and Floquet theorem are used in some selected values of the parameters of the initial stress (magnitude of static and dynamic components of the initial stress). The fourth-order Runge-Kutta algorithm is used for numerical analysis of the equation of motion. The results show that the parameters of initial stress have direct impact on the stability of dynamic response. The obtained results from theoretical and numerical methods which are notably consistent with each other demonstrate that the initial stress, which has been almost always neglected in dynamic models of the systems, has a significant effect on the dynamics of the system, and it may even lead to an unstable dynamic response, while the excitation frequency is far enough from resonance region. So this paper can present the other application of modal analysis to non-destructive measure of initial stress. 相似文献
216.
The synthesis of 2-amino-3-aryl-5-substituted thiophenes as anti-inflammatory agents catalyzed by KF-Al2O3 under microwave irradiation is reported. 相似文献
217.
J. J. Lim R. MacKenzie S. Sujecki M. Dumitrescu S. M. Wang M. Sadeghi G. Adolfsson J. Gustavsson A. Larsson E. C. Larkins 《Optical and Quantum Electronics》2008,40(14-15):1181-1186
In this work, we perform a multi-parameter design study to improve the performance of an uncooled directly modulated 1.3 μm GaInNAs ridge waveguide laser for high speed operation especially at high temperature. The static and dynamic performance of the improved design is analyzed using an accurate in-house 2D electro-opto-thermal laser simulator. The improved structure is shown to have a lower threshold current, higher thermal roll-over limit and higher modulation bandwidth—especially under high temperature operation. The improved structure also has a lower vertical beam divergence compared to a reference structure with a conventional design. 相似文献
218.
Many physical and scientific phenomena are modeled by nonlinear partial differential equations (NPDEs); it is difficult to
handle nonlinear part of these equations. Recently some analytical methods are applied to solve such equations. In this work,
modified Camassa–Holm and Degasperis–Procesi equation is studied. Adomian’s decomposition method (ADM) is applied to obtain
solution of this equation. The results are compared to those of homotopy perturbation method (HPM) and exact solution. The
study highlights the significant features of the employed method and its ability to handle nonlinear partial differential
equations. 相似文献
219.
Elahe Moazzen Nasser Daei Seyyedeh Mahdieh Hosseini Homeira Ebrahimzadeh Azam Monfared Mostafa M. Amini Omid Sadeghi 《Mikrochimica acta》2012,178(3-4):367-372
We have developed a technique for the solid-phase extraction of gold using various kinds of pyridine-functionalized nanoporous silica prior to its determination in various samples using FAAS. The effects of solution pH, sample and eluent flow rate, sample volume and of potentially interfering ions are compared. The limits of detections vary from 28 to 53?pg?mL?1. The accuracy and precision are between 99.8% and 98.3?% and 0.7 to 1.6?% (RSD), respectively. The method was successfully applied to several standard reference materials. Figure
A technique has been developed for the solid-phase extraction of gold using various kinds of pyridine-functionalized nanoporous silica prior to its determination in various samples using FAAS. 相似文献
220.
Karim Mahnam Amir Sadeghi Mehrdad Mohammadpour Afshin Fassihi 《Monatshefte für Chemie / Chemical Monthly》2012,12(6):19-27