排序方式: 共有93条查询结果,搜索用时 15 毫秒
51.
Naseri N Yousefi M Moradlou O Moshfegh AZ 《Physical chemistry chemical physics : PCCP》2011,13(10):4239-4242
The physical and photoelectrochemical properties of the anodized ZnO-TiO(2) thin films were investigated in this study. Impedance spectroscopy revealed a decrease in charge transfer resistance and Tafel plots determined enhancement of about 200 times in the exchange current (i(0)) after anodization at high positive potential. It was found from XPS analysis that after applying the potential of 5 V to the ZnO-TiO(2) photoelectrode, the lattice oxygen (O(2-)) in the thin film is oxidized to molecular oxygen and then, cations such as Zn(2+) can be solved in the basic electrolyte and passed to the solution. Moreover, according to AFM analysis it was observed that the surface of the samples has been grooved by applying anodic voltage resulting in an increase of effective surface of the film. A mechanism for describing the significant enhancement in the photoresponse of the anodized layer is proposed. 相似文献
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Hajizadeh Alireza Bahramian Ahmad Reza Seifi Azadeh Naseri Iman 《Journal of Sol-Gel Science and Technology》2015,74(1):220-226
Journal of Sol-Gel Science and Technology - New carbon aerogels were prepared using Novolac sol as precursor. The elaboration process and the structural characterizations of these porous carbon... 相似文献
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Carson Chu Ali Naseri Tirthankar Mitra Mehran Dadsetan Anton Sediako Murray J. Thomson 《Proceedings of the Combustion Institute》2021,38(2):2525-2532
The relationship between soot surface growth, soot nanostructure and reactant temperature (Tr) in a coflow diffusion ethylene flame was investigated with multiple experimental techniques. The Tr was raised by heating the coflow air. Three cases, with 300K, 473K, and 673K Tr, respectively, were studied. Laser-induced Incandescence revealed that increasing Tr promotes soot formation. Although soot primary particle diameter (dp) also increases with Tr, the increase in dp slows down after 473K Tr, suggesting that there is a deceleration in soot surface growth. Transmission Electron Microscopy (TEM) imaging showed that increased Tr promotes soot aggregation and yields larger and more mature primary particles. The assessment of the Selected Area Electron Diffraction (SAED) patterns indicated that, at 673K Tr, there is a growth of lattice planes. Raman spectroscopy revealed further structural details. By assessing the band intensity ratios, soot for the Tr of 673K has more curved nanostructures. The deceleration of soot surface growth may be explained by surface aging, which is characterized by an increase in curved nanostructures. 相似文献
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Mahshid Manouchehri Shahram Seidi Mohammad Taghi Naseri Ahmad Rouhollahi 《Journal of separation science》2022,45(2):594-601
In the present research, a blended polyacrylamide-chitosan hydrogel was synthesized. For the first time, the prepared sorbent was efficiently employed in a hydrogel-based spin-column setup as a promising format. The proposed method was applied for monitoring the trace amounts of ketoconazole, clotrimazole, and miconazole in blood samples. Effective adsorption and desorption parameters were optimized using a central composite design and the one-variable-at-a-time method. Under the optimal conditions, the calibration curves were linear in the range of 15.0–1000.0, 1.0–1000.0, and 2.0–1000.0 ng mL–1 for ketoconazole, clotrimazole, and miconazole, respectively, along with intra- and interday precision less than 8.4%. Limits of detection were obtained between 0.2 and 5.0 ng mL–1. The preconcentration factors were found in the range of 5.9–7.8. The introduced method was successfully applied for micro-solid-phase extraction of trace amounts of target antifungal drugs in blood samples, followed by liquid chromatography-tandem mass spectrometry. Satisfactory relative recoveries of 94.5–103.5% were obtained, implying method reliability. Overall, the proposed method provides good accuracy and repeatability, high reusability, and good applicability to determine antifungal drugs in complex biological matrices. 相似文献
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The security of a secure quantum sealed-bid auction protocol using quantum secure direct communication based on GHZ states [M. Naseri, Opt. Commun. 282 (2009) 1939] is reexamined. It is shown that the protocol does not complete the task of a sealed-bid auction fairly. It is shown that a dishonest bidder can obtain all the other one’s secret bids by two special types of attack, i.e., double Controlled NOT attack or using fake entangled particles. Furthermore, a simple possible improvement of the protocol is proposed. 相似文献
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We consider the spin-1/2 Heisenberg chain with alternating spin exchange in the presence of additional modulation of exchange on odd bonds with period 3. We study the ground state magnetic phase diagram of this hexamer spin chain in the limit of very strong antiferromagnetic (AF) exchange on odd bonds using the numerical Lanczos method and bosonization approach. In the limit of strong magnetic field commensurate with the dominating AF exchange, the model is mapped onto an effective XXZ Heisenberg chain in the presence of uniform and spatially modulated fields, which is studied using the standard continuum-limit bosonization approach. In the absence of additional hexamer modulation, the model undergoes a quantum phase transition from a gapped phase into the only one gapless Lüttinger liquid (LL) phase by increasing the magnetic field. In the presence of hexamer modulation, two new gapped phases are identified in the ground state at magnetization equal to [Formula: see text] and [Formula: see text] of the saturation value. These phases reveal themselves also in the magnetization curve as plateaus at corresponding values of magnetization. As a result, the magnetic phase diagram of the hexamer chain shows seven different quantum phases, four gapped and three gapless, and the system is characterized by six critical fields which mark quantum phase transitions between the ordered gapped and the LL gapless phases. 相似文献
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S. A. Beyramabadi H. Eshtiagh-Hosseini M. R. Housaindokht S. Shirzadi A. Morsali M. A. Naseri 《Journal of Structural Chemistry》2013,54(6):1055-1062
A new Schiff base ligand N,N′-bis(2,4-dihydroxybenzylidene)-1,2-diaminobenzene [=H2L] and its Cu(II) complex [Cu(L)] are synthesized and characterized by IR, UV-Vis, NMR, mass spectrometry and elemental analysis. Also, the computational prediction of optimized geometries, IR spectra and NMR chemical shifts is performed using the density functional theory (DFT) method. The DFT optimized geometry of the ligand is not planar, so the three benzene rings are located in separate planes. The phenolic protons are engaged in the intramolecular hydrogen-bonding interactions. In the optimized geometry of the square comlex, dianionic L2? acts as a tetradentate ligand, which occupies four coordination positions in the N, N, O?, O? manner. The consistency between the calculated and experimental results confirms the validity of the optimized structures for the H2L ligand and its Cu complex. 相似文献
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H. Eshtiagh-Hosseini S. A. Beyramabadi M. Mirzaei A. Morsali A. R. Salimi M. A. Naseri 《Journal of Structural Chemistry》2013,54(6):1063-1069
In this work, a 3,3′-dihydroxy-4,4′-[1,2-cyclohexanediyl-bis(nitrilomethylidyne)]-bis-phenol [=H2L] Schiff-base ligand and its Mn(II) complex [Mn(L)(H2O)2] are newly synthesized and characterized by elemental analysis, IR and NMR spectroscopies. Also the geometry optimizations, assignment of the IR bands and NMR chemical shifts are computed using the density functional theory (DFT) method. The DFT optimized geometry of the ligand is not planar; each of the cyclohexane and two benzene rings are located in separate planes. The phenolic protons are engaged in the intramolecular-hydrogen-bonding interactions with azomethine nitrogen atoms. In the optimized geometry of the octahedral Mn2+ complex, the dianionic L2? acts as a tetradentate ligand in the N, N, O?, O? manner, where the coordinating atoms occupy the four equatorial positions. The two axial positions are occupied by two H2O ligands. The theoretical and experimental results are in good agreement, confirming the validity of the optimized geometries for the H2L ligand and its Mn complex. 相似文献