The exact partition function of the two-dimensional nearest neighbour Ising model pertaining to s... more The exact partition function of the two-dimensional nearest neighbour Ising model pertaining to square lattices is derived for N sites in the case of a non-vanishing magnetic field.When the magnetic field is zero,the partition functions estimated from the present analysis are identical with those arising from Onsager's exact solution.
The interfacial behavior of thallium ions on polycrystalline silver electrodes is analyzed using ... more The interfacial behavior of thallium ions on polycrystalline silver electrodes is analyzed using cyclic voltammetric and chronocoulometric and impedance studies. The specificity associated with bromide ions leading to the anion-induced adsorption of the thallium complex is pointed out and the stoichiometry of the thallium complex is deduced.
ABSTRACT Silver dendritic structures have been prepared using constant potential deposition on in... more ABSTRACT Silver dendritic structures have been prepared using constant potential deposition on indium tin oxide (ITO) electrodes from an aqueous solution of AgNO3 and KNO3 without any surfactants or structure directing agents. The applied potential is shown to be a crucial factor in the formation of dendrites. Depending upon the magnitude of the applied potentials, morphologies vary from polygons to dendrites. The shape evolution of the silver dendrites has been investigated by varying the deposition time and metal precursors. The mechanism of formation of dendrites is interpreted using the diffusion limited aggregation (DLA) model. The fractal dimensions of the dendrites calculated using the box counting algorithm are in agreement with those predicted by the DLA model. The Ag dendrites coated ITO electrodes exhibit excellent electrocatalytic activity toward oxidation of hydrazine in alkaline medium. The sensing of hydrazine is carried out with amperometry, where from the limit of detection and linear calibration range is deduced as 0.5 μM and 100–1700 μM respectively. The effect of ascorbic acid, urea, ethanol, glucose, K+, Cl−, Br− and I− ions as possible interfering agents in the detection of hydrazine is analyzed.
The efficacy of silver-deposited glassy carbon electrode for the determination of lead ions at th... more The efficacy of silver-deposited glassy carbon electrode for the determination of lead ions at the sub-nanomolar concentration ranges is investigated. The silver nanoparticles are electrodeposited on glassy carbon electrode using chronoamperometry and the electrode surface is characterized using SEM. Lead ions are detected in the region of underpotential deposition. The analysis is performed in square wave mode in the stripping voltammetry without the removal of oxygen. The detection limit of 10 pM has been obtained with a constant potential of -0.7 V during the electrodeposition step for a period of 50s. The interference of surfactants in the detection of lead ions is also studied.
... modelling V SUDHA and MV SANGARANARAYANAN* Department of Chemistry, Indian Institute of Techn... more ... modelling V SUDHA and MV SANGARANARAYANAN* Department of Chemistry, Indian Institute of Technology Madras, Chennai 600 036, India e-mail: mvs@chem.iitm.ac.in MS received 28 January 2005; revised 6 May 2005 ... Page 2. V Sudha and MV Sangaranarayanan 208 ...
ABSTRACT The electrochemical behaviour of thyroxine (T4) is analysed using the disposable screen-... more ABSTRACT The electrochemical behaviour of thyroxine (T4) is analysed using the disposable screen-printed carbon electrode (SPCE) in the neutral phosphate buffer solution with cyclic voltammetric technique. The Differential Pulse Voltammetry and Chronoamperometry were employed for sensing of T4. The lowest detection limit of 3 nM was obtained from the differential pulse voltammetric method without preconditioning. The Density Functional Theoretical study of T4 was performed to elucidate the mechanism of oxidation. The analysis of the commercial pharmaceutical samples indicates the validity of the proposed method.
The exact partition function of the two-dimensional nearest neighbour Ising model pertaining to s... more The exact partition function of the two-dimensional nearest neighbour Ising model pertaining to square lattices is derived for N sites in the case of a non-vanishing magnetic field.When the magnetic field is zero,the partition functions estimated from the present analysis are identical with those arising from Onsager's exact solution.
The interfacial behavior of thallium ions on polycrystalline silver electrodes is analyzed using ... more The interfacial behavior of thallium ions on polycrystalline silver electrodes is analyzed using cyclic voltammetric and chronocoulometric and impedance studies. The specificity associated with bromide ions leading to the anion-induced adsorption of the thallium complex is pointed out and the stoichiometry of the thallium complex is deduced.
ABSTRACT Silver dendritic structures have been prepared using constant potential deposition on in... more ABSTRACT Silver dendritic structures have been prepared using constant potential deposition on indium tin oxide (ITO) electrodes from an aqueous solution of AgNO3 and KNO3 without any surfactants or structure directing agents. The applied potential is shown to be a crucial factor in the formation of dendrites. Depending upon the magnitude of the applied potentials, morphologies vary from polygons to dendrites. The shape evolution of the silver dendrites has been investigated by varying the deposition time and metal precursors. The mechanism of formation of dendrites is interpreted using the diffusion limited aggregation (DLA) model. The fractal dimensions of the dendrites calculated using the box counting algorithm are in agreement with those predicted by the DLA model. The Ag dendrites coated ITO electrodes exhibit excellent electrocatalytic activity toward oxidation of hydrazine in alkaline medium. The sensing of hydrazine is carried out with amperometry, where from the limit of detection and linear calibration range is deduced as 0.5 μM and 100–1700 μM respectively. The effect of ascorbic acid, urea, ethanol, glucose, K+, Cl−, Br− and I− ions as possible interfering agents in the detection of hydrazine is analyzed.
The efficacy of silver-deposited glassy carbon electrode for the determination of lead ions at th... more The efficacy of silver-deposited glassy carbon electrode for the determination of lead ions at the sub-nanomolar concentration ranges is investigated. The silver nanoparticles are electrodeposited on glassy carbon electrode using chronoamperometry and the electrode surface is characterized using SEM. Lead ions are detected in the region of underpotential deposition. The analysis is performed in square wave mode in the stripping voltammetry without the removal of oxygen. The detection limit of 10 pM has been obtained with a constant potential of -0.7 V during the electrodeposition step for a period of 50s. The interference of surfactants in the detection of lead ions is also studied.
... modelling V SUDHA and MV SANGARANARAYANAN* Department of Chemistry, Indian Institute of Techn... more ... modelling V SUDHA and MV SANGARANARAYANAN* Department of Chemistry, Indian Institute of Technology Madras, Chennai 600 036, India e-mail: mvs@chem.iitm.ac.in MS received 28 January 2005; revised 6 May 2005 ... Page 2. V Sudha and MV Sangaranarayanan 208 ...
ABSTRACT The electrochemical behaviour of thyroxine (T4) is analysed using the disposable screen-... more ABSTRACT The electrochemical behaviour of thyroxine (T4) is analysed using the disposable screen-printed carbon electrode (SPCE) in the neutral phosphate buffer solution with cyclic voltammetric technique. The Differential Pulse Voltammetry and Chronoamperometry were employed for sensing of T4. The lowest detection limit of 3 nM was obtained from the differential pulse voltammetric method without preconditioning. The Density Functional Theoretical study of T4 was performed to elucidate the mechanism of oxidation. The analysis of the commercial pharmaceutical samples indicates the validity of the proposed method.
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