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641.
The response characteristics and selectivity coefficients of an unmodified carbon paste electrode (CPEs) towards Ag+, Cu2+ and Hg2+ were evaluated. The electrode was used as an indicator electrode for the simultaneous determination of the three metal ions in their mixtures via potentiometric titration with a standard thiocyanate solution. A three-layered feed-forward artificial neural network (ANN) trained by back-propagation learning algorithm was used to model the complex non-linear relationship between the concentration of silver, copper and mercury in their different mixtures and the potential of solution at different volumes of the added titrant. The network architecture and parameters were optimized to give low prediction errors. The optimized networks were able to precisely predict the concentrations of the three cations in synthetic mixtures. 相似文献
642.
Abbas Ali Rostami Mohammad Javad Chaichi Mostafa Sharifi 《Monatshefte für Chemie / Chemical Monthly》2007,138(10):967-971
Summary. Density (ρ) and viscosity (η) values of the binary mixtures of DMP + 1-pentanol, 1-butanol, and 1-propanol over the entire range of mole fraction at 298.15 and 303.15 K were measured in atmospheric
pressure. The excess molar volume (V
E), viscosity deviations (Δη), and excess Gibbs energy of activation for viscous flow (G*E) were calculated from the experimental measurements. These results were fitted to Redlich–Kister polynomial equation to estimate the binary interaction parameters.
The viscosity data were correlated with equations of McAllister. The calculated functions have been used to explain the intermolecular interaction between the mixing components. 相似文献
643.
As a counterpart to best approximation in normed linear spaces, best coapproximation was introduced by Franchetti and Furi.
In this paper, we shall show that if M is a separable, coproximinal subspace of X satisfying some additional conditions, then L
1 (S, M) is coproximinal in L
1(S, X).
相似文献
644.
645.
646.
In this research, potassium permanganate in the presence of a catalytic amount of [bmim]Br under solvent free conditions is used as an efficient and chemoselective method for oxidative cleavage of some oximes to corresponding carbonyl compounds. This experiment was carried out in mild conditions without any further oxidation of aldehydes to corresponding acids. 相似文献
647.
In this paper a multiple strained layer structure with multiple quantum wells as a piezoelectric transducer is proposed for
generating and detecting nano ultrasound waves with nanometer wavelength and tera hertz frequency. By inducing femtosecond
optical pulses at this strained structure, internal piezoelectric field is changed. As a result longitudinal acoustic phonon
oscillations can be treated as nano acoustic waves. It could be noticed in simulated cases that detection of nano ultrasound
waves can be used in non destructive testing and high accuracy measurements with this structure. It is also shown that the
MQW structure design how influences in generated nano acoustic waves. 相似文献
648.
Jamshid Sabbaghzadeh Parvaneh Jafarkhani Siamak Dadras Mohammad Javad Torkamany 《Applied Physics A: Materials Science & Processing》2009,94(2):293-297
Synthesis of multi-wall carbon nanotubes in a 1473 K furnace using a copper vapor laser (CVL) is reported. The operating parameters
of this laser, i.e. a high fluence at the focal point and an extremely high frequency of 10 kHz, distinguished it from common
laser sources in the synthesis of CNTs. Therefore, the unexpected experimental findings, the formation of MWNTs instead of
the generally reported SWNTs, would be verified by these two notable parameters. Electron microscopy beside Raman spectroscopy
illustrates the presence of multi-wall carbon nanotubes in the resulting product. 相似文献
649.
Javad S. Z. Sabounchei Brian T. Heaton Jonathan A. Iggo Chacko Jacob Ivan S. Podkorytov 《Journal of Cluster Science》2001,12(1):339-348
A complete NMR study involving both 1D and 2D 13C-{103Rh} and 31P-{103Rh} HMQC measurements, on [Rh6C(CO)14(PPh3)]2- are reported and discussed, together with the multiple Rh quantum effects found for resonances associated with edge- and face-bridging CO's. As found in [Rh6C(CO)15]2-, the carbonyl ligands in [Rh6C(CO)14(PPh3)]2- undergo CO-intermolecular exchange with 13CO at different rates; for the edge-bridging CO's, the lower the value of 1J(Rh–CO), the faster the rate of intermolecular exchange with 13CO. 相似文献
650.
NiAl2O4 spinel nanocrystals were synthesized as mesoporous catalysts and were fully characterized using Fourier‐transform infrared spectroscopy (FT‐IR), X‐ray diffraction patterns (XRD), scanning electron microscopy (SEM), and Energy‐dispersive X‐ray spectroscopy (EDS). These nanocrystals catalyzed the synthesis of 2,3‐dihydroquinazolin‐4(1H)‐one derivatives via a one‐pot, three‐component condensation reaction of aromatic aldehydes, isatoic anhydride, and ammonium acetate or primary aromatic amine under microwave irradiation. By far, the most obvious advantages of the offered process are efficiency and recyclability of the catalyst as well as a significantly shorter reaction time. 相似文献