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排序方式: 共有156条查询结果,搜索用时 15 毫秒
61.
Hayet Benzarouk Abdelaziz Drici Mounira Mekhnache Abdelaziz Amara Mouhamed Guerioune Jean Christian Bernède Hacen Bendjffal 《Superlattices and Microstructures》2012
In the present work we studied the influence of the dopant elements and concentration on the microstructural and electrochemical properties of ZnO thin films deposited by spray pyrolysis. Transparent conductive thin films of zinc oxide (ZnO) were prepared by the spray pyrolysis process using an aqueous solution of zinc acetate dehydrate [Zn(CH3COO)2·2H2O] on soda glass substrate heated at 400 ± 5 °C. AlCl3, MgCl2 and NiCl2 were used as dopant. The effect of doping percentage (2–4%) has been investigated. Afterwards the samples were thermally annealed in an ambient air during one hour at 500 °C. X-ray diffraction showed that films have a wurtzite structure with a preferential orientation along the (0 0 2) direction for doped ZnO. The lattice parameters a and c are estimated to be 3.24 and 5.20 ?, respectively. Transmission allowed to estimate the band gaps of ZnO layers. The electrochemical studies revealed that the corrosion resistance of the films depended on the concentration of dopants. 相似文献
62.
Mouhamed Moustapha Fall 《Nonlinear Analysis: Theory, Methods & Applications》2012,75(2):951-963
Let Ω be a smooth bounded domain in RN with N≥1. In this paper we study the Hardy-Poincaré inequalities with weight function singular at the boundary of Ω. In particular we give sufficient conditions so that the best constant is achieved. 相似文献
63.
64.
Ahmed O. H. El Nezhawy Mostafa M. Ramla Nagy M. Khalifa Mohamed M. Abdulla 《Monatshefte für Chemie / Chemical Monthly》2009,38(5):531-539
Abstract 4-Fluorobenzaldehyde was used for the preparation of 2-(4-fluorophenyl)thiazolidin-4-one derivatives which were allowed to
react with chloroacetonitrile and acrylonitrile to produce 3-(2-(4-fluorophenyl)-4-oxothiazolidine3-yl)acetonitrile and 3-(2-(4-fluorophenyl)-4-oxothiazoledine-3-yl)propanenitrile.
Biological evaluation of some of the compounds showed that many had promising antioxidant activity.
Graphical Abstract
相似文献
65.
Hatem A. Abdel-Aziz Bakr F. Abdel-Wahab Marwa A. M. Sh. El-Sharief Mohamed M. Abdulla 《Monatshefte für Chemie / Chemical Monthly》2009,140(4):431-437
Abstract The reaction of 1-[4-(piperidin-1-yl)benzylidene]thiosemicarbazide with hydrazonoyl chlorides afforded 1,3-thiazole derivatives.
Cyclization of two compounds of the latter 1,3-thiazole by means of bromine in the presence of sodium acetate at room temperature
gave 1,3-thiazolo[2,3-c]-1,2,4-triazole derivatives. The reaction of 2-cyano-3-(4-piperidin-1-ylphenyl)prop-2-enethioamide with hydrazonoyl chlorides
under reflux in ethanol in the presence of triethylamine yielded 1,3-thiazoles. Treatment of 3-oxo-3-(piperidin-1-yl)propanenitrile
with phenyl isothiocyanate in DMF, in the presence of KOH, at ambient temperature, resulted in the formation of 3-anilino-3-mercapto-2-(piperidin-1-ylcarbonyl)acrylonitrile
which was reacted with hydrazonoyl chlorides to yield the corresponding 1,3,4-thiadiazole derivatives. Some of the newly synthesized
compounds had significant anti-arrhythmic activity.
Graphical Abstract
相似文献
66.
Abdulla S.A.A. Al-Rizzo H.M. Cyril M.M. 《Antennas and Propagation, IEEE Transactions on》1988,36(1):114-126
Several windblown and dustfall samples were collected in the spring, summer, and autumn of 1984 at 20 m above the ground surface during severe sand and dust storms in the city of Baghdad, Iraq. The particle-size distribution (PSD) of the samples was determined using five different measurement techniques (hydrometer, pipette, sedimentation balance, optical microscope, and Coulter counter). The results showed that the cumulative weight techniques yield almost identical results for all the samples tested. The mode of the number distribution was found to occur at around 2 and 3.5 μm for the blowing and falling dust samples, respectively. A computer program was developed to describe the measured distributions by some analytical functions. It was found that the cumulative distributions can be well described by a third-degree polynomial and log-normal functions for particle diameters ranging from 1 to 100 μm. The attenuation α and phase shift β for a microwave signal were estimated for up to 37 GHz utilizing the measured PSD and for different particle moisture contents. It was concluded that at 37 GHz and for 10 m visibility, the upper bound for α and β were 0.7 dB/km and 26.5 degree/km for 20% particle-moisture content 相似文献
67.
Cyclodehydrohalogenation by terminal N1-C4 bond formation affords N-aryl-4-benzoyl-2-azetindinones from 3-benzoyl-3-bromopropionanilides in an unequivocal annelation process. 相似文献
68.
Aljowder OA 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2004,60(12):2837-2841
Raman spectra of the thiomolybdate ion in the compounds [Cu.NH4][MoS4] and X2[MoS4], where X=NH4+, Rb+ or Cs+, are reported and used to confirm the hypothesis presented in an earlier paper [J. Chem. Phys. 94 (1991) 5946], that there is solid state induced vibrational coupling between the nu1 and nu3 modes of tetrahedral ions. 相似文献
69.
Summary Cobalt(III) complexes of the typetrans-[Co(AA)2(ox)] (where AA = aminoacidato, gly = glycinato, sar = sarcosinato, DL-ala = DL-alaninato, L-ala = L-alaninato; ox = oxalate); [Co(L-val)2CO3] and DL-[Co(en)2sar]I2 where L-val = L-valinato, en = ethylenediamine) have been investigated for their bacterial activity againstEscherichia coli B using well-cultured techniques on EMB agar and in minimal glucose media. The activities decrease in the order:trans-(N)(+)K[Co(sar)2(ox)] >trans-(N)(+)K[Co(L-ala)2(ox)] >trans-(N)(–)K[Co (gly)2(ox)] >trans-(N)(+)K[Co(DL-ala)2(ox)] >trans-(N)(+)K[Co(gly)2(ox)] >trans(+)K[Co(DL-ala)2(ox)] >trans-K[Co(L-val)2CO3]. 相似文献
70.
Abd El-Galil E. Amr Nermien M. Sabry Mohamed M. Abdulla 《Monatshefte für Chemie / Chemical Monthly》2007,138(7):699-707
Summary. A series of pyridines, pyrimidinones, and oxazinones were synthesized as anti-inflammatory agents using citrazinic acid (2,6-dihydroxyisonicotinic
acid) as a starting material. Acryloyl pyridine was treated with cyanothioacetamide to give cyano pyridine-thione, which was
reacted with ethyl chloroacetate to yield the corresponding amino ester. The ester was hydrolysed to the sodium salt, which
was treated with acetic anhydride to afford 2-methyloxazinone, which was treated with ammonium acetate to afford 2-methylpyrimidinone
followed by methylation with methyl iodide to yield 2,3-dimethylpyrimidinone. In addition, the oxazinone derivative was reacted
with aniline or hydrazine hydrate to give 3-phenyl- or 3-aminopyrimidinones. The latter reacted with thiophene-2-carboxaldehyde
or phenylisothiocyanate to afford Schiff’s bases or thiosemicarbazides. 3-Aminopyrimidinone was treated with phthalic anhydride or 1,2,4,5-benzenetetracarboxylic
acid dianhydride or toluene-3,5-diisocyanate to afford the corresponding imide, bis-imide, and bis-semicarbazide derivatives. The pharmacological screening showed that many of these compounds have good anti-inflammatory
activity comparable to Prednisolone? as reference drug. 相似文献