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751.
Jalilian Niloofar Ebrahimzadeh Homeira Asgharinezhad Ali Akbar Molaei Karam 《Mikrochimica acta》2017,184(7):2191-2200
Microchimica Acta - The authors describe the synthesis of a nanosorbent for fast magnetic solid phase extraction of trace levels of Ag(I), Au(III), Pd(II) and Pt(II). It consists of graphene oxide... 相似文献
752.
Solvent extraction of thorium from nitric acid solutions using di-N-butyl sulfoxide (DBSO) in xylene
Muhammad Haleem Khan Syed Moosa Hasany Akbar Ali Muhammad Ali Khan 《Journal of Radioanalytical and Nuclear Chemistry》1995,198(2):409-421
The extraction of thorium(IV) from nitric acid solutions by di-n-butyl sulfoxide (DBSO) in xylene has been investigated as a function of acid, extractant and the metal concentration. The effect of contact time and diverse ions on the extraction has been examined. Phosphate, fluoride, oxalate and perchlorate reduce the extraction to some extent. The extraction of other metal ions, especially impurities associated with thorium in ores, has been measured under optimised conditions selected for thorium extraction. Na(I), K(I), Ca(II), Sr(II), Mn(II), Fe(II), Ni(II), Zn(II), Pb(II), Al(III), Ti(IV) and Hf(IV) are not extracted. Among the stripping solutions employed for back-extraction, deionized water is found to be the best and more than 99% thorium can be back-extracted in three stages. The extracted species is supposed to be Th(NO3)4·2DBSO. The extraction is found to be almost independent of the thorium concentration in the range between 4.3·10–4–4.3·10–2M and inversely dependent upon the temperature. The values of thermodynamic functions H, G and S for extraction equilibrium have been evaluated to be –19.6±2.9 kJ·mole–1, –18.1±2.0 kJ·mole–1 and –5.0±2.9 J·mole–1·K–1, respectively. 相似文献
753.
Mohammad Akbar Ali Aminul H. Mirza Ray J. Butcher Paul V. Bernhardt Mohammad Rezaul Karim 《Polyhedron》2011,30(9):2237-1486
Condensation of di-2-pyridyl ketone with S-methyldithiocarbazate or S-benzyldithiocarbazate yields potentially bridging ligands of the form Py2CNNHC(S)SR; Hdpksme (R = Me; the di-2-pyridyl ketone Schiff base of S-methyldithiocarbazate) and Hdpksbz (R = Bz; the di-2-pyridyl ketone Schiff base of S-benzyldithiocarbazate). Complexation of these ligands with Cu(II) in a 1:1 M ratio leads to the formation of dinuclear complexes of the general formula [Cu(NNNS)X]2 (X = Cl−, NO3−, H2O). X-ray crystallographic structure determinations show that each ligand provides three donor atoms (NNS) in a meridional configuration to one metal, viz. one of the pyridine nitrogen atoms, the azomethine nitrogen atom and the thiolate sulfur, while the nitrogen atom of the second pyridyl group forms a bridge to another copper(II) ion within the dimer. The coordination geometry around each copper(II) ion is approximately square pyramidal, the basal plane of which is composed of one of the pyridine nitrogen atoms, the azomethine nitrogen atom and a chlorido, nitrato or aqua ligand. The apical position of the square pyramid is always occupied by the pyridine nitrogen atom of the second ligand. 相似文献
754.
Naser Montazeri Samad Khaksar Akbar Nazari Seyed Mohammad Vahdat 《Journal of fluorine chemistry》2011,132(7):450-5946
Pentafluorophenylammonium triflate (PFPAT) is used as an efficient catalyst in the von Pechmann condensation of phenols with β-ketoesters leading to the formation of coumarin derivatives. Short reaction times, easy and quick isolation of the products, excellent chemoselectivity, excellent yields and ease of catalyst recovery with consistent activity makes this protocol efficient and environmentally benign. 相似文献
755.
756.
Ali Akbar Mehrvarz Kamal Bahmanpour Reza Naghipour 《Algebras and Representation Theory》2014,17(4):1207-1215
The purpose of this paper is to give some equivalent conditions to the socle and Bass numbers’ conjectures which raised by Huneke in (Res Notes Math 2:93–108,). In addition, some results about certain Gorenstein ideals are included. 相似文献
757.
Communicated by 相似文献
758.
The improved F-expansion method is a rising approach to obtain new and broad-spectrum exact solutions to the nonlinear evolution equations in the field nonlinear sciences. In this study, the influential F-expansion method is used to extract the analytical solutions of the nonlinear Klein–Gordon equation with the aid of symbolic computation software Maple. We successfully establish the solutions in the form of hyperbolic, trigonometric and rational function structure. The derived solutions could be imperious and significant for narrating the physical phenomena in the real-world. For suitable values of the parameter involved in the solutions, we depict the 2D and 3D graphs of some obtained exact solutions. 相似文献
759.
In this work, we propose a high-order accurate method for solving the one-dimensional heat and advection–diffusion equations. We apply a compact finite difference approximation of fourth-order for discretizing spatial derivatives of these equations and the cubic C1-spline collocation method for the resulting linear system of ordinary differential equations. The cubic C1-spline collocation method is an A-stable method for time integration of parabolic equations. The proposed method has fourth-order accuracy in both space and time variables, i.e. this method is of order O(h4,k4). Additional to high-order of accuracy, the proposed method is unconditionally stable which will be proved in this paper. Numerical results show that the compact finite difference approximation of fourth-order and the cubic C1-spline collocation method give an efficient method for solving the one-dimensional heat and advection–diffusion equations. 相似文献
760.
Akbar Karimi Hadi Nobahari Patrick Siarry 《Computational Optimization and Applications》2010,45(3):639-661
A new hybrid optimization method, combining Continuous Ant Colony System (CACS) and Tabu Search (TS) is proposed for minimization
of continuous multi-minima functions. The new algorithm incorporates the concepts of promising list, tabu list and tabu balls
from TS into the framework of CACS. This enables the resultant algorithm to avoid bad regions and to be guided toward the
areas more likely to contain the global minimum. New strategies are proposed to dynamically tune the radius of the tabu balls
during the execution and also to handle the variable correlations. The promising list is also used to update the pheromone
distribution over the search space. The parameters of the new method are tuned based on the results obtained for a set of
standard test functions. The results of the proposed scheme are also compared with those of some recent ant based and non-ant
based meta-heuristics, showing improvements in terms of accuracy and efficiency. 相似文献