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51.
Maryam Mohammadikish Fatemeh Davar Mohammad Reza Loghman-Estarki 《Journal of Cluster Science》2013,24(1):217-231
In this work, we report a facile hydrothermal method for the preparation of three dimensional hollow ZnS nanostructures, using Zinc bis(salicyle aldehitato), Zn(Sal)2, thioacetamide (TAA) and thioglycolic acid (TGA) as Zn2+, sulfur source and capping agent, respectively. The ZnS solid and hollow sphere was produced from the self-assembly of nanoparticles with diameters of 11 ± 2 nm with TGA and TGA, TAA, respectively. Furthermore, with changing zinc precursor from Zn(Sal)2 to zinc acetate [Zn(OAC)2], ZnS nanorods were obtained. The products were characterized by XRD, SEM, TEM, selected area electron diffraction, and FT-IR spectra. The influence of surfactant (Polyethylene glycol) on the morphology of the products was also investigated. Possible formation mechanism and optical properties of these architectures were also reported. 相似文献
52.
Hamid Reza Momenian Sousan Gholamrezaei Masoud Salavati-Niasari Behnam Pedram Farhang Mozaffar Davood Ghanbari 《Journal of Cluster Science》2013,24(4):1031-1042
In this work Mg(OH)2, Ca(OH)2, CaCO3, SrCO3 and BaCO3 nanoparticles were synthesized via a simple sonochemical reaction at room temperature. Nanoparticles were synthesized via a surfactant-free reaction solvent water. Nanostructures materials were characterized by scanning electron microscopy, X-ray diffraction and fourier transform infrared spectroscopy. The photocatalytic behavior of nanoparticles was evaluated using the degradation of a methyl orange aqueous solution under ultraviolet light irradiation. The results show that metal hydroxide and metal carbonate nanoparticles are promising materials with excellent performance in photocatalytic applications. 相似文献
53.
Mohammad Reza Islami Zahra Hassani Hassan Sheibani 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):2547-2554
Phthalimide or succinimide undergo a reaction with dialkyl acetylenedicarboxylates and triphenylphosphine to produce highly-functionalized stable heterocyclic phosphorus ylides in good yields in water-tetrahydrofuran (6:1). This methodology is of interest because of the use of water as solvent, thus minimizing the cost, operational hazards, and environmental pollution. 相似文献
54.
In this paper, we provide a new measure for evaluation of risk in financial markets. This measure is based on the return interval of critical events in financial markets or other investment situations. Our main goal was to devise a model like Value at Risk (VaR). As VaR, for a given financial asset, probability level and time horizon, gives a critical value such that the likelihood of loss on the asset over the time horizon exceeds this value is equal to the given probability level, our concept of Time at Risk (TaR), using a probability distribution function of return intervals, provides a critical time such that the probability that the return interval of a critical event exceeds this time equals the given probability level. As an empirical application, we applied our model to data from the Tehran Stock Exchange Price Index (TEPIX) as a financial asset (market portfolio) and reported the results. 相似文献
55.
Muhammad Ali Ehsan Muhammad Adil Mansoor Muhammad Mazhar Asif Ali Tahir Mazhar Hamid K. G. Upul Wijayantha 《应用有机金属化学》2012,26(9):493-498
A single molecular heterobimetallic complex, [Co2Ti(μ3‐O)(TFA)6(THF)3] (1) [TFA = trifluoroacetate, THF = tetrahydrofuran], was synthesized, structurally and spectroscopically characterized and implemented as a single‐source precursor for the preparation of CoTiO3–CoO composite thin films by aerosol‐assisted chemical vapour deposition (AACVD). The precursor complex was prepared by interaction of Co(OAc)2.4H2O [OAc = (CH3COO?)] with Ti(iso‐propoxide)4 in the presence of trifluoroacetic acid in THF, and was analysed by melting point, CHN, FT‐IR, single‐crystal X‐ray diffraction and thermogravimetric analysis. The precursor complex thermally decomposed at 480 °C to give a residual mass corresponding to a CoTiO3–CoO composite material. Good‐quality crystalline CoTiO3–CoO composite thin films deposited at 500 °C by AACVD and characterized through powder X‐ray diffraction and scanning electron microscopy/energy‐dispersive X‐ray spectroscopy show that the crystallites have a rose‐flower‐like morphology with an average petal size in the range of 2–6 µm. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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Reza Ghiasi 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2013,87(13):2231-2238
The density functional theory (DFT) is used to study the geometries, and electronic structures of triplet and singlet of borazyne and B-substituted of borazyne. The aromaticity of these systems is analyzed in the light of nucleus-independent chemical shift (NICS), average of two-center indices (ATI). These methods show increasing of aromaticity in deactivating groups. The relation between electron density in ring critical point (RCP) and NICS(1.0) is observed. The most important interaction in these molecules has been investigated by natural bonding orbital method (NBO). 相似文献
59.
Firouz Matloubi Moghaddam Zohreh Mirjafary Marjan Jebeli Javan Sara Motamen Hamid Saeidian 《Tetrahedron letters》2014
A mild and efficient tandem process for the synthesis of new highly substituted 2-pyrones starting from commercially available 2-arylacetic acids has been developed. The synthesis is based on the Knoevenagel condensation of 1,3-cyclohexadiones with various β-formyl-esters, followed by lactonization in the presence of nano ZnO (20 mol %). Moderate to high yields and readily available cheap starting materials are the key features of the present method. 相似文献
60.
Taher Niknam Mohammad Hassan Khooban Abdollah Kavousifard Mohammad Reza Soltanpour 《Nonlinear dynamics》2014,75(1-2):73-83
This study deals with the problem of controlling a class of uncertain nonlinear systems in the presence of external disturbances. To achieve this goal, a new Optimal Type-2 Fuzzy Sliding Mode Controller (OT2FSMC) is introduced. In the proposed controller, a novel heuristic algorithm, namely particle swarm optimization with random inertia weight (RNW–PSO), is employed. To achieve an optimal performance, the parameters of the proposed controller as well as the input and output membership functions are optimized simultaneously by RNW–PSO. The globally asymptotic stability of the closed-loop system is mathematically proved. Finally, this method of control is applied to the inverted pendulum system as a case study. Simulation results show the system performance is desirable. 相似文献