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1.
Satyawati S. Joshi Prajakta R. Patil Madhav S. Nimase P.P. Bakare 《Journal of nanoparticle research》2006,8(5):635-643
The electrochemical synthesis of alpha Fe2O3 nanoparticles was performed using quaternary ammonium salts viz. TPAB, TBAB and TOAB in an organic medium by optimizing current density and molar concentration of the ligand. The role of ligands in the formation of α phase, structure and magnetic properties was investigated in details. The effect of increasing chain length on the particle size confirmed that as the chain length increases from propyl to octyl, the particle size decreases. X-ray diffraction spectra of as prepared samples and TEM analysis confirmed the amorphous nature of iron oxide. TEM showed beads of iron oxide joined together with a size distribution in the range of 6–30 nm. The Mossbauer studies also support this observation that for the lowest particle size, the line width is broader which successively reduces with increase in particle size. Iron oxide capped with TOAB indicated superparamagnetic nature at room temperature. The resultant internal magnetic field of 506 mm/s due to hyperfine splitting clearly established the formation of α-Fe2O3 The infrared spectroscopy and pH measurements revealed the binding of tetra alkyl ligand with iron oxide. The IR spectra and the increase in basicity of as prepared samples confirmed the formation of hydrated iron oxide. Above 800°C the spectra indicated only iron oxide. Surface area obtained by BET method was 205 m2/g. 相似文献
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Udeochu U Jimerson T Vivoni A Bakare O Hosten CM 《The journal of physical chemistry. A》2007,111(17):3409-3415
A complete assignment of the Raman active modes of 1,10-phenanthroline-5,6-dione in the 100-4000 cm(-1) spectral region is reported. Intense well resolved spectra of solid phendione with high S/N are reported. Assignment of the normal modes with appropriate symmetry representation symbols was achieved by employing density functional theory calculations. Our calculations were modeled on results previously reported for phenanthroline. Results of the B3LYP calculations were consistent and established that phendione possess sixty fundamentals. 相似文献
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In this paper, based on the theory of stochastic differential equations, we study the outer synchronization between two different complex dynamical networks with noise coupling. The theoretical result shows that two different complex networks can achieve generalized outer synchronization only with white-noise-based coupling. Numerical examples further verify the effectiveness and feasibility of the theoretical results. Numerical evidence shows that the synchronization rate is proportional to the noise intensity. 相似文献
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Refat Moamen S. Altalhi T. Bakare Safyah B. Al-Hazmi Ghaferah H. Alam Kehkashan 《Russian Journal of General Chemistry》2021,91(5):890-896
Russian Journal of General Chemistry - Transition metals such as Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Zn(II), Cd(II), and Hg(II) have been reacted with gibberellic acid (HGA) to give novel... 相似文献
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C. E. Deshpande P. P. Bakare M. N. S. Murthy N. Y. Vasanthacharya P. Ganguly 《Journal of Chemical Sciences》1982,91(3):261-266
Magnetic susceptibility studies of Mn1-xMxO (M = Zn, x≤0.1; M = Mg, x≤0.12;M = Fe, x≤0.4) in the range 77 to 300 K are reported. The methods of preparation of Mn1-xMxO systems preclude the presence of trivalent ions. The M1-xFexO system shows anomalous behaviour aroundx = 0.2–0.3. The results are discussed in terms of competition between the nearest neighbour and the next-near-neighbour interactions,
dilution effects and cooperative effects of FeO6 octahedra. 相似文献
8.
P. P. Bakare S. K. Date Y. B. Khollam S. B. Deshpande H. S. Potdar S. Salunke-Gawali F. Varret E. Pereira 《Hyperfine Interactions》2006,168(1-3):1127-1132
Microwave–hydrothermal (MH) route was employed to synthesize various iron oxide phases in ultra-fine crystalline powders by using ferrous sulphate and sodium hydroxide as starting chemicals. All chemical reactions were carried out under identical MH conditions, namely, at 190°C, 154 psi, 30 min, by varying the molar ratio (MR) of FeSO4/NaOH in the aqueous solutions. The variation of MR has a dramatic effect on the crystallization behavior of various phases of iron oxides under MH processing conditions. For example, spherical agglomerates of Fe3O4 powder were obtained if MR equal to 0.133 (pH?>?10 sample A). On the other hand non-stoichiometric Fe3O4 powders (Sample B) were obtained for all higher MR of FeSO4/NaOH between 0.133 and 4.00 (6.6?2O3 powders (sample C) were produced. Fe57 Mössbauer spectra were recorded for all the three sets of samples at room temperature. In the case of sample B, temperature dependent Mössbauer spectra were recorded in the range of 77–300 K to understand the non-stoichiometric nature of Fe3O4 powders. All these results are discussed in the present paper. 相似文献
9.
Highly stable Fe1?δO:Al3+ system has been synthesized by checking the spontaneous disproportionation of FeO. The novel preparation route of incorporating non-magnetic trivalent Al3+ ions in the wustite lattice is followed for the preparation of solid solutions. X-ray diffraction (XRD), chemical analysis and Fe57 Mössbauer effect are used for the characterization. The hyperfine interaction parameters reported are characteristic of high spin Fe2+ state which confirmed the stabilization of FeO. 相似文献
10.
Rane S. Y. Gawali S. D. Kumbhar A. S. Padhye S. B. Bakare P. P. 《Journal of Thermal Analysis and Calorimetry》1999,55(1):249-258
Copper(II) complexes of lawsone (2-hydroxy-1,4-naphthaquinone, Lw) with variety of aqua ligation viz. Cu-1, [Cu(Lw)2(H2O)]2; Cu-2, [Cu(Lw)2(H2O)2] and Cu-3, [Cu(Lw)2(H2O)2]2 have been synthesized. The role of water as counter ligand on coordination propensity of redox active lawsone in naphthoquinone/naphthosemiquinone
(NQ/NSQ) forms is quantified by studies of pyrolytic reactions, using non-isothermal TG and DTA techniques, coupled with IR
studies. Mixed (NQ) (NSQ) ligation in Cu-1 and Cu-3 required energy of activation, Ea ∼67 kJ mol−1 of (NQ) and ∼41 kJ mol−1 of (NSQ). Comparable energies of aqua ligand (∼43 kJ mol−1) with NSQ ligand in Cu-1 and Cu-3, dictate charge distributions in lawsone coordinations. A large difference between Ea of aqua and p-NQ ligand indicates coordination of lawsone in its fully oxidised quinone form in Cu-2. From thermoanalytical
studies schematic oxidative decomposition mechanisms are proposed for Cu-1 and Cu-3. From pyrolytic reactions enthalpies are
estimated by DTA technique.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献