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21.
A general analytical expression has been deduced for the I/E response of the square wave voltammetry corresponding to ion transfer processes in systems with two liquid/liquid polarized interfaces. This expression has been evaluated through the experimental study of a series of quaternary ammonium cations and metal chloro complex anions. We have found that systems with two liquid/liquid polarizable interfaces present the striking advantage that the difference between peak potentials of square wave voltammograms of cations and anions with similar standard ion transfer potential is much greater than in systems with a single polarizable one. 相似文献
22.
Joaquín A. Ortuño Carmen Serna Angela Molina Encarnación Torralba 《Electroanalysis》2009,21(21):2297-2302
Square wave voltammetry (SWV) with a solvent polymeric membrane ion sensor has been applied to study the ion transfer of several ionic liquid cations, from water to a poly(vinyl chloride) membrane plasticized with 2‐nitrophenyl octyl ether. The study has mainly been focused on dialkylimidazolium and alkylpyridinium cations. The experimental voltammograms obtained are in good agreement with the theoretical predictions. The standard ion transfer potentials of the ionic liquid cations have been obtained and the values found have been used to draw some conclusions on the relationship between structure and lipophilicity. Also, a relationship between the toxicity and the ion transfer potentials of dialkylimidazolium homologues has been found. 相似文献
23.
M.C. Torralba J.A. Campo E. Pinilla M.R. Torres 《Journal of organometallic chemistry》2006,691(4):765-778
Two types of Pd-complexes containing the new N,N′-ligands 2-[3-(4-alkyloxyphenyl)pyrazol-1-yl]pyridine (pzRpy; R = C6H4OCnH2n+1, n = 6 (hp), 10 (dp), 12 (ddp), 14 (tdp), 16 (hdp), 18 (odp)) (1-6), namely c-[Pd(Cl)2(pzRpy)] (7-10) and c-[Pd(η3-C3H5)(pzRpy)]BF4 (11-16), have been synthesised and characterised by different spectroscopic techniques. Those members of the second type containing the largest chains (R = ddp 13, tdp 14, hdp 15, odp 16) have been found to have liquid crystal properties showing smectic A mesophases. By contrast, neither the free ligands pzRpy nor their related c-[Pd(Cl)2(pzRpy)] complexes exhibited mesomorphism. The new synthesised metallomesogens are mononuclear complexes with an unsymmetrical molecular shape as deduced from the X-ray structures of c-[Pd(η3-C3H5)(pzRpy)]BF4 (R = hp, 11; dp, 12). Both compounds, which are isostructural, show a distorted square-planar environment on the palladium centres defined by the allyl and the bidentate pzRpy ligands. The crystal structure reveals that both the counteranion and the pzRpy ligand function as a source of hydrogen-bonding and intermolecular π?π contacts resulting in a 2D supramolecular assembly. 相似文献
24.
Galvan E. Torralba A. Franquelo L.G. 《Industrial Electronics, IEEE Transactions on》1996,43(6):655-660
A common method in adjustable speed drives uses an incremental shaft encoder and an electronic circuit for velocity estimation. The usual method of counting pulses coming from the encoder in a fixed period of time produces a high-precision velocity estimate in the high-speed range. High precision in the low-speed range can be achieved measuring the elapsed time between two successive pulses coming from the encoder. In this paper, a mixed method that combines the best of the two previously mentioned approaches has been implemented using a simple electronic circuit based on one field-programmable gate array (FPGA) and one read-only memory (ROM) 相似文献
25.
J.A. Galán R.G. Carvajal F. Muñoz A. Torralba J. Ramírez-Angulo 《Analog Integrated Circuits and Signal Processing》2003,37(3):275-280
This letter presents a new low-voltage class-AB differential linear OTA. The proposed transconductor uses a novel scheme based on two cross-coupled class-AB pseudo-differential pairs biased by a Flipped Voltage Follower [1]. The transconductor has been designed using a 0.8 m CMOS technology to operate at 2 V supply voltage with only 260 W of quiescent power consumption. Simulation results show 90 MHz bandwidth with more than two decades of transconductance tuning range. 相似文献
26.
Torralba A. Carvajal R.G. Jimenez M. Munoz F. Ramirez-Angulo J. 《Electronics letters》2006,42(3):152-154
A new, simple, low-voltage class-AB unity-gain buffer is presented. The proposed approach combines use of floating-gate transistors with the flipped voltage follower to create a compact topology. Experimental results are provided that prove the proposed approach. 相似文献
27.
The transfer of the protonated forms of heptylamine, octylamine, decylamine, procaine and procainamide facilitated by dibenzo-18-crown-6 from water to a solvent polymeric membrane has been investigated by using cyclic square wave voltammetry. The experimental voltammograms obtained are in good agreement with theoretical predictions. The values of the standard ion transfer potential, complexation constant and diffusion coefficient in water have been obtained from these experiments, and have been used to draw some conclusions about the lipophilicity of these species and the relative stability of the organic ammonium complexes with dibenzo-18-crown-6. The results have been compared with those provided by linear sweep voltammetry. Calibration graphs were obtained with both techniques. An interesting chronoamperometric method for the determination of the diffusion coefficient of the target ion in the membrane has been developed and applied to all these protonated amines. 相似文献
28.
Torralba A. Martinez-Heredia J.M. Carvajal R.G. Ramirez-Angulo J. 《Electronics letters》2002,38(25):1616-1617
A linear tunable CMOS transconductor is proposed which uses a new low-voltage supercascode transistor to provide a high output resistance. Using a standard 0.8 /spl mu/m CMOS technology, simulation results are provided that show the operation of the proposed transconductor with a 1.2 V peak-to-peak differential input signal and 1.5 V supply voltage. The proposed transconductor features a high linearity and more than 100 MHz bandwidth. 相似文献
29.
30.
Felix Loeffler Christopher Schirwitz Jenny Wagner Kai Koenig Frieder Maerkle Gloria Torralba Michael Hausmann F. Ralf Bischoff Alexander Nesterov‐Mueller Frank Breitling 《Advanced functional materials》2012,22(12):2503-2508
Biofunctionalization of surfaces in a microarray format has revolutionized biological assay applications. Here, a microarray system based on a microelectronic chip is presented that allows for a versatile combinatorial in situ molecule synthesis with very high density. Successfully demonstrating an application for peptide array synthesis, the method offers a compact approach, high combinatorial freedom, and, due to the intrinsic alignment, high and reproducible precision. Patterning the chip surface with different microparticle types which imbed different monomers, several thousand different molecule types can be simultaneously elongated layer‐by‐layer by coupling the particle imbedded monomers to the molecules growing on the chip surface. This technique has the potential for a wide application in combinatorial chemistry, as long as the desired monomeric building blocks are compatible with the chemical process. 相似文献