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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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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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SHUbarICHI NOSÉ 《Molecular physics》2013,111(1):191-198
A molecular dynamics simulation method which can generate configurations belonging to the canonical (T, V, N) ensemble or the constant temperature constant pressure (T, P, N) ensemble, is proposed. The physical system of interest consists of N particles (f degrees of freedom), to which an external, macroscopic variable and its conjugate momentum are added. This device allows the total energy of the physical system to fluctuate. The equilibrium distribution of the energy coincides with the canonical distribution both in momentum and in coordinate space. The method is tested for an atomic fluid (Ar) and works well. 相似文献
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Timothy R. Totsch Victoria L. Stanford Oleksander Klep Mary K. Burdette Benjamin Grant Stephen H. Foulger Gary M. Gray 《Journal of polymer science. Part A, Polymer chemistry》2020,58(13):1825-1842
Linear polyphosphonates with the generic formula –[P(Ph)(X)OR′O]n– (X = S or Se) have been synthesized by polycondensations of P(Ph)(NEt2)2 and a diol (HOR′OH = 1,4-cyclohexanedimethanol, 1,4-benzenedimethanol, tetraethylene glycol, or 1,12-dodecanediol) followed by reaction with a chalcogen. Random copolymers have been synthesized by polycondensations of P(Ph)(NEt2)2 and mixture of two of the diols in a 2:1:1 mol ratio followed by reaction with a chalcogen. Block copolymers with the generic formula –[P(Ph)(X)OR′O](x + 2) –[P(Ph)(X)OR′O](x + 3)– (X = S or Se) have been synthesized by the polycondensations of Et2N[P(Ph)(X)OR′O](x + 2)P(Ph)NEt2 oligomers with HOR′O[P(Ph)(X)OR′O](x + 3)H oligomers followed by reaction with a chalcogen. The Et2N[P(Ph)(X)OR′O](x + 2)P(Ph)NEt2 oligomers are prepared by the reaction of an excess of P(Ph)(NEt2)2 with a diol while the HOR′O[P(Ph)(X)OR′O](x + 3)H oligomers are prepared by the reaction of P(Ph)(NEt2)2 with an excess of the diol. In each case the excess, x is the same and determines the average block sizes. All of the polymers were characterized using 1H, 13C{1H}, and 31P{1H} NMR spectroscopy, TGA, DSC, and SEC. 31P{1H} NMR spectroscopy demonstrates that the random and block copolymers have the expected arrangements of monomers and, in the case of block copolymers, verifies the block sizes. All polymers are thermally stable up to ~300°C, and the arrangements of monomers in the copolymers (block vs. random) affect their degradation temperatures and Tg profiles. The polymers have weight average MWs of up to 3.8 × 104 Da. 相似文献
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The attenuation of the reflected light from a polystyrene (PS) polymerized crystalline colloidal array (PCCA) is achieved through the electrochemical switching of the electrochromic material polyaniline-poly(2-acrylamido-2-methyl-1-propanesulfonicacid) (PANI-PAMPS). For this purpose, layered electrochromic devices (ECDs) were fabricated that employed a PS PCCA film, acting as both a reflecting substrate and polymeric electrolyte, and the conducting polymer PANI-PAMPS, which served as the electrochromic layer. The resulting ECDs exhibited the attenuation of reflectance peak at the stop band position of the PCCA with a 3% of reflectance contrast ratio. 相似文献
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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
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Robust polymer colloidal crystal photonic bandgap structures 总被引:1,自引:0,他引:1
Foulger SH Kotha S Sweryda-Krawiec B Baughman TW Ballato JM Jiang P Smith DW 《Optics letters》2000,25(17):1300-1302
New polymeric matrices are presented that embed organic colloidal crystalline arrays (CCA's) into mechanically stable photonic bandgap structures. We achieved these new matrices either by dispersing polystyrene CCA's with high molecular weight hydrophilic polymer [poly(ethylene glycol); (PEG)] or through in situ polymerization of hydrophilic monomers (acrylamide and acrylate functional PEG variants) about the CCA. CCA-dispersed PEG matrices exhibited strong red opalescence with a narrow peak at 614 nm and were sufficiently rigid to withstand repeated mechanical deformation. Visible photonic bandgaps also were observed from free-standing CCA composites with cross-linked poly(N, N-dimethylacrylamide) matrices. The results demonstrate the technological potential for robust organic photonic crystals. 相似文献