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5‐Amino‐4‐methyl‐2‐phenyl‐6‐substitutedfuro[2,3‐d]pyrimidines ( 2a‐c ) were reacted with 2,5‐dimethoxytetrahydrfuran to afford the pyrrolyl derivatives 3a‐c . Compound 3a was chosen as intermediate for the synthesis of poly fused heterocycles incorporated furopyrimidines moiety 4–11 . Some of the synthesized compounds were screened for their antibacterial and antifungal activities. 相似文献
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Balakin V Alexandrov VA Mikhailichenko A Flöttmann K Peters F Voss G Bharadwaj V Halling M Holt JA Buon J Jeanjean J LeDiberder F Lepeltier V Puzo P Heimlinger G Settles R Stierlin U Hayano H Ishihara N Nakayama H Oide K Shintake T Takeuchi Y Yamamoto N Bulos F Burke D Field R Hartman S Helm R Irwin J Iverson R Rokni S Roy G Spence W Tenenbaum P Wagner SR Walz D Williams S 《Physical review letters》1995,74(13):2479-2482
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Braverman Michael SH.; Stepanov Vladimir D. 《Bulletin London Mathematical Society》1994,26(3):283-287
Necessary and sufficient conditions for the boundedness of thediscrete Hardy operator of the form , from to when 0 < q < 1 <p , is given. 相似文献
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Anthony PL Arnold RG Band HR Borel H Bosted PE Breton V Cates GD Chupp TE Dietrich FS Dunne J Erbacher R Fellbaum J Fonvieille H Gearhart R Holmes R Hughes EW Johnson JR Kawall D Keppel C Kuhn SE Lombard-Nelsen RM Marroncle J Maruyama T Meyer W Meziani Z Middleton H Morgenstern J Newbury NR Petratos GG Pitthan R Prepost R Roblin Y Rock SE Rokni SH Shapiro G Smith T Souder PA Spengos M Staley F Stuart LM Szalata ZM Terrien Y Thompson AK White JL Woods M Xu J Young CC Zapalac G 《Physical review D: Particles and fields》1996,54(11):6620-6650
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Lung A Stuart LM Bosted PE Andivahis L Alster J Arnold RG Chang CC Dietrich FS Dodge WR Gearhart R Gomez J Griffioen KA Hicks RS Hyde-Wright CE Keppel C Kuhn SE Lichtenstadt J Miskimen RA Peterson GA Petratos GG Rock SE Rokni SH Sakumoto WK Spengos M Swartz K Szalata Z Tao LH 《Physical review letters》1993,70(6):718-721
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A.SH. Hussein Z. Hassan S.M. Thahab Abu Hassan M.A. Abid C.W. Chin 《Physica B: Condensed Matter》2011,406(6-7):1267-1271
We have studied the structural properties of undoped and Si-doped AlxGa1?xN/GaN/AlN on Si (1 1 1) substrate prepared by plasma-assisted molecular beam epitaxy (PA-MBE) using high-resolution X-ray diffraction (HR-XRD) and atomic force microscopy (AFM). In comparison with undoped AlGaN, the roughness and dislocation density on the surface of the AlGaN layer decrease with Si doping. Full width half maximum (FWHM) of the undoped and Si-doped samples were equal to 0.69° and 0.52°, respectively. This indicates that the Si doping improves the crystalline quality of the AlxGa1?xN layer compared with the undoped one. Raman scattering measurement reveals that the optical phonon modes of A1(LO) and E2(H) of the AlGaN show a one-mode and two-modes behavior, respectively. The Fourier-transform infrared reflectance (FTIR) investigation confirms the one-mode (two-mode) behavior of the LO (TO) phonon in our samples. This is in good agreement with Raman measurement. Finally, the barrier height (ΦB) of undoped and Si-doped AlxGa1?xN samples was found to be 0.86 and 0.74 eV, respectively. 相似文献
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Shahrokh Hosseini-Hashemi Mohammad Fadaee Hossein Rokni Damavandi Taher 《Applied Mathematical Modelling》2011
In this paper, exact closed-form solutions in explicit forms are presented for transverse vibration analysis of rectangular thick plates having two opposite edges hard simply supported (i.e., Lévy-type rectangular plates) based on the Reddy’s third-order shear deformation plate theory. Two other edges may be restrained by different combinations of free, soft simply supported, hard simply supported or clamped boundary conditions. Hamilton’s principle is used to derive the equations of motion and natural boundary conditions of the plate. Several comparison studies with analytical and numerical techniques reported in literature are carried out to demonstrate accuracy of the present new formulation. Comprehensive benchmark results for natural frequencies of rectangular plates with different combinations of boundary conditions are tabulated in dimensionless form for various values of aspect ratios and thickness to length ratios. A set of three-dimensional (3-D) vibration mode shapes along with their corresponding contour plots are plotted by using exact transverse displacements of Lévy-type rectangular Reddy plates. Due to the inherent features of the present exact closed-form solution, the present findings will be a useful benchmark for evaluating the accuracy of other analytical and numerical methods, which will be developed by researchers in the future. 相似文献
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Amirhossein Hajihosseini Farzaneh Maleki Gholam Reza Rokni Lamooki 《Chaos, solitons, and fractals》2011,44(11):1004-1019
A class of recurrent neural networks is constructed by generalizing a specific class of n-neuron networks. It is shown that the newly constructed network experiences generic pitchfork and Hopf codimension one bifurcations. It is also proved that the emergence of generic Bogdanov–Takens, pitchfork–Hopf and Hopf–Hopf codimension two, and the degenerate Bogdanov–Takens bifurcation points in the parameter space is possible due to the intersections of codimension one bifurcation curves. The occurrence of bifurcations of higher codimensions significantly increases the capability of the newly constructed recurrent neural network to learn broader families of periodic signals. 相似文献