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1.
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
2.
3.
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
4.
5.
Kinetics and Mechanism of Dehydrochlorination of 3‐Chloro‐1,5‐diarylformazans and Their Mass Spectra
In aqueous dioxane containing triethylamine the title 3‐chloroformazans 1 are converted into the corresponding 1,4‐bis(arylazo)‐3,6‐diaryl‐1,2,4,5‐tetrazines 3 via head‐to‐tail dimerization of the intitially formed 1,3‐dipolar ions 2. The kinetics of triethylamine‐catalyzed dehydrochlorination of 1 in 70% dioxane at 27°C and ionic strength of 0.1 were studied. The rate data were linearly correlated with enhanced Hammett substituent constants σx? and an overall ρ value of 0.2 was determined for the variation of the N‐aryl substituent. These results were interpreted in terms of a two‐step mechanism. Also, the mechanisms of the unimolecular fragmentation of 1 and 3 in the mass spectrometer are discussed. 相似文献
6.
7.
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
8.
Abdelwahed R. Sayed 《Tetrahedron letters》2010,51(34):4490-4493
Efficient syntheses of 1,3,4-thiadiazoles and bis-thiadiazoles by the reaction of hydrazonoyl halides with carbonothioic dihydrazide are reported. In addition, 1,2,4-triazolo[3,4-b][1,3,4]thiadiazole is obtained via oxidative cyclization of bis-(substituted methylene)carbonothioic dihydrazone. 相似文献
9.
Metal/superconductor/semiconductor (Ag/Hg-1212/CdSe) hetero-nanostructures have been fabricated using pulse-electrodeposition
technique and are characterized by X-ray diffraction (XRD), full-width at half-maximum (FWHM) and scanning electron microscopy
(SEM) studies. The junction capacitance of Ag/Hg-1212, Hg-1212/CdSe and Ag/Hg-1212/CdSe heterojunctions is measured in dark
and under laser irradiation at room temperature. The nature of the junction formed and built-in-junction potentials were determined.
The increase in carrier concentration across the junction due to photo-irradiation has been observed. 相似文献
10.
One of the innovative technological directions for the high-temperature superconductors has been persued by fabricating the
heteroepitaxial multilayer structures such as superconductor-semiconductor heterostructures. In the present investigation,
metal/superconductor/semiconductor (Ag/Tl-2223/CdSe) hetero-nanostructures have successfully been fabricated using dc electrodeposition
technique and were characterized by X-ray diffraction (XRD), full-width at half-maximum (FWHM) and scanning electron microscopy
(SEM) studies. The measurement of junction capacitance as a function of biasing voltage was used for the estimation of junction
built-in-potential (V
D) and to study the charge distribution in a heterojunction. The Mott-Schottky plots were measured for each junction in dark
and under the photo-irradiation. The effect of laser irradiation on C-V characteristics of hetero-nanostructure has been studied. 相似文献