排序方式: 共有19条查询结果,搜索用时 31 毫秒
1.
N. Foroughifar A. Mobinikhaledi M. Amrollahi M. Zendehdel 《Applied magnetic resonance》2004,26(4):483-488
C(2)-H exchange incis-[(en)2Co(HIm)(enH)]Br4 (Im, imidazole; en, ethylenediamine) was studied over a pD range of 9.4 to 10.2 at 60°C where thecis-[(en)2Co(Him)(enH)]4+ andcis-[(en)2Co(HIm)(en)]3+ are the species present in significant concentrations.Cis-[(en)2Co(HIm)(enH)]4+ has pKa1 7.86 and pKa2 9.82 with pKa1 corresponding to coordinated enH ionization and pKa2 to ImH ionization. The kinetic data may be interpreted in terms of an intramolecular H-D exchange mechanism, where the “dangling”-ND2CH2CH2ND2 group acts as a base to remove the imidazole C(2)-H proton from the coordinated DIm moiety. 相似文献
2.
M. MolaeiE. Saievar Iranizad M. MarandiN. Taghavinia R. Amrollahi 《Applied Surface Science》2011,257(23):9796-9801
We have synthesized CdS nanocrystals (NCs) by a microwave activated method. CdSO4 and Na2S2O3 were used as the precursors and thioglycolic acid (TGA) was used as capping agent molecule. The aqueous synthesis was based on the heat sensitivity of Na2S2O3. In this method, microwave irradiation creates the activation energy for dissociation of Na2S2O3 and leads to the CdS NCs formation. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses demonstrated hexagonal phase CdS NCs with an average size around 3 nm for sample prepared at 5 min irradiation time. A band gap range of 3.38-2.89 eV was possible only by increasing the microwave irradiation time, corresponding to a 2.7-3.7 nm size. Photoluminescence (PL) spectra showed a white emission between 400 and 750 nm. The best attained PL quantum yield (QY) of the NCs was about 10%. Synthesized NCs were used as emissive layer in a light emitting device (LED) with ITO/PEDOT:PSS/PVK/CdS-NCs/AL structure. Turn on voltage of fabricated device was about 7 V. The CIE color coordinate of the LED at (0.34, 0.43) demonstrated a near white light LED with an emission on green-yellow boundary of white. 相似文献
3.
Mohammad Ali Amrollahi Zohreh Kheilkordi 《Journal of the Iranian Chemical Society》2016,13(5):925-929
A convenient and direct approach has been developed for the preparation of bis(indole) derivatives by one-pot four-component condensing of indole, aldehydes and active methylene compounds in the presence of 12-tungstophosphoric acid in aqueous media under silent and ultrasound methods. The remarkable advantages are the simplicity of the experimental procedures, short reaction times and high yields with the green aspects by avoiding toxic catalysts and solvents. 相似文献
4.
Hamzavi Seyedeh Fazileh Jamili Shahla Yousefzadi Morteza Mashinchian Moradi Ali Amrollahi Biuki Narges 《Molecular diversity》2020,24(4):985-995
Molecular Diversity - In this work, we reported a facile synthesis of Pt nanoparticles (NPs) on proline-functionalized cross-linked chitosan particles to catalyze the reduction of R-NO2 to R-NH2 in... 相似文献
5.
In recent years, the modi?cation of metal oxides with noble metals to decrease the loading amount of expense of noble metal catalyst and amend the stability of nanocatalyst in chemical reactions has attracted signi?cant attention. Here in this study, the urchin-like double-shelled Pd–PdO/ZnO hollow sphere is successfully prepared by using a simple hydrothermal method and carbon sphere as a hard template. The structure of the catalyst was confirmed by using field-emission scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, energy-dispersive X-ray spectroscope, and BET. The total amount of palladium particles on ZnO was determined by induced coupled plasma analysis. The prepared catalyst gave high catalytic activity for the Suzuki reaction of aryl halides to afford biphenyls under milder conditions. Furthermore, the stability and reusability of catalyst were investigated, and all of the data proved that urchin-like double-shelled Pd–PdO/ZnO hollow sphere could be recycled five times without marked loss of activity. 相似文献
6.
In this paper, we present the result of TiN nanocrystalline deposition on SS316L, using a 4 kJ plasma focus (PF) device for 10, 20, and 30 focus shots. The effect of different number of focus shots on micro-structural changes of thin film is characterized by field emission scanning electron microscope. Existence of grains in different size confirms the formation of TiN nanocrystals on the surface of SS316L substrate. X-ray diffraction (XRD) reveals the formation of a nanocrystalline titanium nitride coating on the surface of SS316L samples. The crystalline size of TiN obtained from XRD data is strongly dependent on the number of focus shots. Thickness of the elements found on the surface of the treated sample that obtain by Rutherford backscattering spectroscopy (RBS) analysis is in the range of 150×1015?200×1015 atoms/cm2. All the existence elements in the coated samples are identified by Particle Induced X-ray Emission (PIXE) spectra. Investigation on the corrosion resistance of TiN coatings was performed using an electrochemical potentiodynamic polarization. Our results suggest that TiN nanocrystalline implantation with proper ion fluences using PF can significantly improve the corrosion resistance of SS316L. 相似文献
7.
S. Goudarzi S.M. Sadat Kiai N. Morshedian A. Nasiri R. Amrollahi 《Czechoslovak Journal of Physics》2005,55(1):45-53
The results of an experimental investigation of neutron emission characteristics in the Filippov-type plasma focus facility Dena (90 kJ, 25 kV, 288 µF) with D2 + %1 Kr as working gas are presented. From the experimental results, one can conclude that both thermonuclear and nonthermonuclear mechanisms are always present in neutron production, but their contributions to the total neutron yield are strongly dependent on the initial pressure and discharge voltage. It has been found that at constant discharge voltages and low pressures the beam—target interaction mechanism plays an important role in the neutron production and with increasing the pressure, its role decreases and the importance of thermonuclear mechanism increases. Also at constant pressures, the contribution of beam—target interaction mechanism in neutron production decreases with increasing the discharge energy. The value of the index in the empirical neutron yield scaling law Yn I E/2 was found to be about 3.82. 相似文献
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9.
D. Shahabi M. A. Amrollahi A. A. Jafari 《Journal of the Iranian Chemical Society》2011,8(4):1052-1057
The oxidative conversion of 1,4-dihydropyridines to give the corresponding pyridine derivatives in excellent yields was easily effected using the catalytic amount of NaI in combination with H2O2 (30%) as a green external oxidant. The process is highly green wherein the solid products are easily filtered out after the addition of ice-water to the reaction mixture. This non-transition metal catalyst is cost-effective, affords simple work-up and easy separation of the product. 相似文献
10.
Shirin Shayegh Hojjat Amrollahi Bioki Mahmood Borhani Zarandi Narjes Kabiri Samani Alireza Rahnamanic 《Polymer Science Series B》2017,59(5):616-623
Hybrid polyaniline based composites incorporating zinc sulfide nanoparticles have been synthesized by using chemical oxidation technique. Morphological and optical properties of the nanocomposite were characterized by scanning electron microscopy, Fourier transform infrared and UV–Vis spectroscopy measurement. The results were compared with pure polyaniline. The characteristic FTIR peaks of polyaniline were found to shift to lower wave-number in nanocomposite. The band gap of nanocomposites increases and the refractive index of the nanocomposites decreases with increasing content of ZnS nanoparticles. These results showed the interaction between ZnS nanoparticles and polyaniline. 相似文献