排序方式: 共有31条查询结果,搜索用时 46 毫秒
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Nezhad MR Alimohammadi M Tashkhourian J Razavian SM 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2008,71(1):199-203
An indirect colorimetric method is presented for detection of trace amounts of hydroquinone (1), catechol (2) and pyrogallol (3). The reduction of AuCl4(-) to Gold nanoparticles (Au-NPs) by these phenolic compounds in the presence of cetyltrimethylammonium chloride (CTAC) produced very intense surface plasmon resonance peak of Au-NPs. The plasmon absorbance of Au-NPs allows the quantitative colorimetric detection of the phenolic compounds. The calibration curves derived from the changes in absorbance at lambda = 568 nm were linear with concentration of hydroquinone, catechol and pyrogallol in the range of 7.0 x 10(-7) to 1.0 x 10(-4)M, 6.0 x 10(-6) to 2.0 x 10(-4)M and 6.0 x 10(-7) to 1.0 x 10(-4)M, respectively. The detection limits were 5.3 x 10(-7), 2.5 x 10(-6) and 3.2 x 10(-7)M for the hydroquinone, catechol and pyrogallol, respectively. The method was applied satisfactorily to the determination of phenolic compounds in water samples and pharmaceutical formulations. 相似文献
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H-point standard addition method (HPSAM) is suggested as a simple and selective method for the determination of semicarbazide and hydrazine. The reduction of Cu2+ to Cu+ by semicarbazide and hydrazine in the presence of neocuproine (Nc) and the subsequent complex formation between Cu+ and Nc produced a sensitive spectrophotometric method for indirect determination of semicarbazide and hydrazine. The difference in the rate of reduction of Cu2+ with semicarbazide and hydrazine in cationic micellar media is the basis of this method. Semicarbazide can be determined in the range of 0.5-3.75 μg ml−1 with satisfactory accuracy and precision in the presence of excess hydrazine. The proposed method was successfully applied to the simultaneous determination of semicarbazide (0.5-3.75 μg ml−1) and hydrazine (0.5-5 μg ml−1) and also to the selective determination of semicarbazide in the presence of hydrazine in several synthetic mixtures containing different concentration ratios of semicarbazide and hydrazine. 相似文献
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Rashidi Saman Hormozi Faramarz Sarafraz Mohammad Mohsen 《Journal of Thermal Analysis and Calorimetry》2021,143(3):1833-1854
Journal of Thermal Analysis and Calorimetry - Boiling process is a highly efficient mechanism of heat transfer, which has an important role in industrial and domestic sectors. In this process, a... 相似文献
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Influences of simultaneous utilization of pin channel and copper–water nanofluid on performance of plate-fin heat exchangers were experimentally explored and compared with results obtained for the base fluid flow inside a plain channel. Experimental results clearly indicate that compared with the plain channel, the pin channel significantly improves the thermal-hydraulic performance of the plate-fin heat exchanger, about 38%. In addition, the heat transfer coefficient as well as pressure drop are increased by using the nanofluids instead of the base fluid. Noticeable average performance factor of 1.65 is obtained for the simultaneous utilization of pin channel and nanofluid inside the plate-fin heat exchanger. 相似文献
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In topological quantum computation, quantum information is stored in states which are intrinsically protected from decoherence, and quantum gates are carried out by dragging particlelike excitations (quasiparticles) around one another in two space dimensions. The resulting quasiparticle trajectories define world lines in three-dimensional space-time, and the corresponding quantum gates depend only on the topology of the braids formed by these world lines. We show how to find braids that yield a universal set of quantum gates for qubits encoded using a specific kind of quasiparticle which is particularly promising for experimental realization. 相似文献
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Khodabakhsh Niknam Abdollah Deris Farhad Panahi M. Reza Hormozi Nezhad 《Journal of the Iranian Chemical Society》2013,10(6):1291-1296
An efficient heterogeneous palladium catalyst system has been developed based on immobilization of Pd nanoparticles on silica-bonded N-propylpiperazine sodium N-propionate (SBPPSP) substrate. SBPPSP substrate can stabilize the Pd nanoparticles effectively so that it can improve their stability against aggregation. In addition, grafted piperazine species on to the silica backbone prevent the removing of Pd nanoparticles from the substrate surface. Transmission electron microscopy (TEM) of catalyst is shown the size of Pd nanoparticles, also it confirmed by particle size analyzer which shown the average size of 21 nm for Pd. The catalytic activity of these catalysts was investigated in the Sonogashira reaction. The catalyst could be recycled several times without appreciable loss in catalytic activity. 相似文献
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Azadi Mostafa Hosseinirad Elham Hormozi Faramarz Rashidi Saman 《Journal of Thermal Analysis and Calorimetry》2020,140(4):1883-1895
Journal of Thermal Analysis and Calorimetry - In this numerical work, a second law analysis is carried out for the nanofluid flow and heat transfer in the mini-channel with finned surface. The... 相似文献
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Rashidi Saman Hormozi Faramarz Sarafraz Mohammad Mohsen 《Journal of Thermal Analysis and Calorimetry》2021,143(3):1815-1832
Journal of Thermal Analysis and Calorimetry - Boiling process can be widely used in different industrial applications. In this two-phase heat transfer, the latent heat of vaporization of a liquid... 相似文献
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Ali Akbar Ashkarran Azam Iraji?zad Seyed Mohammad Mahdavi Mohammad Mahdi Ahadian Mohammad Reza Hormozi?Nezhad 《Applied Physics A: Materials Science & Processing》2009,96(2):423-428
The microstructural (XRD and SEM) and dielectric behavior of Pb(Zr0.54Ti0.46)O3 (PZT 54/46) ceramic system with donor (La, Nb and La+Nb) doping was studied. For all Nb-doped PZT samples, only one (tetragonal) phase was found, which confirms the compositional
shifts near the morphotropic phase boundary. For La- and La+Nb-doped samples, there are two (rhombohedral and tetragonal)
phases. Dielectric characteristic behavior (1/ε) for La- and La+Nb-doped PZT was associated with two-phase transitions: Ferro–Ferro at low temperature and Ferro–Para at Curie temperature.
For Nb-doped samples, only one phase transition is observed, which indicates the presence of a single ferroelectric phase. 相似文献